Fasting – is that what you’re really doing?


Run a search on the word “fasting” and you will undoubtedly get back hundreds of results, most of which will lead you to websites loaded with a mix of information ranging from half truths to excursions into the absurd.  So, what’s the deal with fasting?  Is it good, bad, or somewhere in between?

The fasting state

Abstinence from food for 18 to 48 hours is called the “fasting state” (1). During the fasting state, glycogen (stored carbohydrate) is depleted and amino acids from muscle protein break down to provide fuel for gluconeogenesis (production of glucose by the liver in the absence of carbohydrate intake) and the body enters a state of ketosis.  (If you thought only low carb diets promoted ketosis, you may want to look at fasting and starvation as something a bit more extreme than low-carb, in that they are both “no-carb”.) Large amounts of nitrogen are lost through urine to keep up with the body’s high rate of muscle protein breakdown and glucose synthesis by the liver (1).

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The starvation state

Abstinence from food for more than 48 hours is called the “starvation state” (1).  While a 24 hour fast is generally a good idea every now and then, starving oneself is not.  So, to be clear:  if you’re abstaining from food for more than 48 hours you are not fasting – you are starving your body of important nutrients.

When fasting turns into starvation, fat stores become the main suppliers of energy as the body tries to hang on to important proteins (enzymes, antibodies, hemoglobin).  Fatty acid levels in the blood increase sharply and the brain and skeletal muscles adapt to using ketones for energy.  The more fat deposits a person has, the longer s/he can survive – in theory.  In practice, the detrimental effects of starvation on the immune system leave people susceptible to infections which, in the absence of protein in the diet, can lead to death.

Purposeful starvation

Most people undertaking a fast, do so for more than 48 hours, which means they are actually engaging in starvation.  On purpose.  I don’t know how long such people keep up this feat, but I suspect most do not run out of fat stores by the time they start eating again.  Thus, they are in no danger of starving to death.  However, there are side effects to starving oneself.

Fasting and starvation rob the body of essential amino acids (EAA), essential fatty acids (EFA), and essential vitamins and minerals (1).  They’re called “essential” for a reason.  We can not produce them ourselves, so, we must get them from food.  If you think you can overcome this problem by juicing while you’re abstaining from food, I hope to relieve you of such fantasies in the next sections.

Juicing

Juicing entails the removal of pulp and nutrient rich skins from fruits and vegetables. As a result, some essential vitamins and minerals, as well as most of the fibre are lost.  This is no big deal if you enjoy the products of juicing as part of an adequate diet, but if you are relying on juice to get you all the nutrients your body needs as you forego solid foods, you are far from reaching your goal.

Protein intake is significantly limited, meaning you’re very likely to experience the side effects of continuously robbing your body of essential amino acids.  I use the word “likely” because, in theory, if you consume enough juice, you will eventually meet your EAA needs.  In practice, this is virtually impossible, since the amount of juice needed would be of astronomical proportions.  Limiting amino acids, particularly lysine, methionine and tryptophan would keep your body from producing adequate amounts of proteins (antibodies, enzymes, hormones, etc.).  The longer you keep it up, the longer your body has to make do with robbing muscles of their proteins to compensate for self-imposed limitations.

Leptin

Our stomachs and adipose cells under the skin secrete a hormone called leptin.  Its job is to keep track of how much fat we store and to suppress appetite after eating by stimulating the release of melanocyte stimulating hormone (MHS) (1).  In addition, leptin alters immune system function.  Fasting decreases basal leptin levels in the body.  Since inducing starvation in human subjects is considered unethical, we can only extrapolate what happens to starving people based on animal models and the study of malnourished persons or those suffering from eating disorders such as anorexia nervosa (2,3).  The effects of leptin imbalances during fasting and starvation are visible in as little as two days in animal models, with immune system suppression occurring at just 48 hours (4).  It should come as no surprise if, during a bout of starvation (water “fasts”) or adhering to a liquid diet yielding inadequate essential nutrients (particularly protein), people succumb to viral, bacterial or fungal infections, among other things.  All it takes is to be in the right place at the right time (in other words, exposure).

Other stuff

In a surprising turn of events, researchers in Israel found that some of their initially obese test subjects, who had no prior diabetic symptoms, developed diabetes after a course of very low calorie dieting (5).  This may have been the result of insulin resistance which usually occurs during early stages of starvation.  The subjects were not starving, but the low caloric intake may have mimicked starvation enough to lead to insulin resistance.

One day fasts and alternate day fasting

This I can support.  There is a fair amount of evidence that one day fasts and alternate day fasting have a number of benefits ranging from weight loss and maintenance to decreased risk of some cancers and cardiovascular disease (see my post on caloric restriction).  Although the most likely to be beneficial, alternate day fasting is the toughest of the two in terms of adherence.  Most people get tired of it within a week or two, many much sooner.  Alternate day fasting results in lowered caloric intake which, as I mentioned in a previous post, has been linked to higher quality of life and possibly longevity.

Finally…

If you’re abstaining from food for more than two days, you are not fasting. You are starving.  I suggest you stop.  If you are engaging in one day fasts or alternate day fasts, more power to you.  If you think juicing while fasting or starving is enough to keep all bodily functions operating properly, you are kidding yourself.  Juicing is the equivalent of a very low calorie diet which is to say, you’re not getting essential nutrients and you’re setting yourself up for infections, weight re-gain after the regimen is over and possibly other issues not readily visible.

I did not touch on the claim that fasts of any kind or starvation of any length act as a way to detoxify the body or liver because I already covered it here.

References

  1. Gropper SS, Smith JL, Groff JL.  Advanced Nutrition and Human Metabolism, 5th Ed. CA: Wadsworth; 2009.
  2. Marcos A, Varela P, Toro O, Lopez I, Nova E, Madruga D, Casas J, Morande G.  Interactions between nutrition and immunity in anorexia nervosa: a 1 year follow-up study.  Am J Clin Nutr, 1997;66(2):485S-490S.
  3. Lord GM, Matarese G, Howard JK, Baker RJ, Bloom SR, Lechler RI. Leptin modulates the T-cell immune response and reverses starvation-induced immunosuppression. Nature 1998;394:897–901.
  4. Faggioni R, Moser A, Feingold KR, Grunfeld C. Reduced leptin levels in starvation increase susceptibility to endotoxic shock. Am J Pathol, 2000;156(5): 1781-1787.
  5. Koffler M, Kisch ES.  Starvation diet and very low calorie diets may induce insulin resistance and overt diabetes mellitus. J Diabetes Complications, 1996;10(2):109-12.
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The skinny on healthy skin


Your skin is your largest organ.  On average, this amounts to about 2 square meters of surface and roughly 3 to 4 kilograms of mass. It helps protect you against potentially harmful substances, extreme temperatures and the Sun’s ultraviolet light. In turn, the skin’s three layers – the epidermis, dermis, and subcutis – depend on you to keep them healthy.  This means taking precautions to avoid the Sun’s damage and meeting your nutritional requirements on a regular basis.

Eat right

Aside from scheduling regular visits to the dermatologist, avoiding direct Sun light for extended periods of time, and wearing Sun screens (hats, long sleeves, umbrellas, lotions), you can make sure you consume a healthy diet which includes vitamins A, B, C, E and omega-3 fatty acids.

Vitamin A

Vitamin A refers to three compounds (retinol, aldehyde, and retinoic acid) called retinoids.  Plants contain carotenoids which are metabolized by the body to form retinoids, the most important of which is B-carotene.  About 50% to 80% of vitamin A in the body is stored in the liver.  The rest is spread out among the lungs, kidneys, adipose tissue and a number of specialized cells throughout the body (1).

Known by most people as being crucial for good vision, vitamin A also plays a role in cell function, growth, development and differentiation (and, thus, is important in keeping our skin healthy), immune function, reproduction and a number of systemic functions, such as gene expression.

The RDA for adults is 700-900 RAE (retinol activity equivalents) which translates into 700-900 mcg of retinol or 8,400-10,800 mcg of B-carotene per day, depending on gender and pregnancy status (1).

  • 1 small sweet potato = 7,374 RAE (about ten times the RDA, or 88,488 mcg of B-carotene)
  • 1 cup raw carrots = 5,553 RAE
  • 1 cup of cooked broccoli = 725 RAE
  • 2 medium tomatoes = 860 RAE
  • 1 cup cooked spinach = 6,882 RAE
  • 1 cup cantaloupe = 1,625 RAE

Given the abundance of carotenoids in the plant world, particularly in the orange and red fruits and vegetables category, it is relatively easy to meet our daily requirements.

Supplementation with vitamin A is contraindicated in the absence of a known deficiency and without medical supervision.  Although readily available in our food supply, vitamin A may be poorly absorbed by some individuals who suffer from pancreatic or liver disease or who lack fat and/or zinc in their diets. On the flip side, vitamin A toxicity is serious business. Regular consumption of vitamin A at 100 times or more the RDA may lead to liver disease, skin disorders, higher incidence of bone fractures (including hip) and lung cancer among smokers (1).

B vitamins

B vitamins, in particular niacin, help keep skin healthy.  Niacin is essential for energy production and metabolism.

Niacin in most plants and grains is covalently bound with peptides and carbohydrates that are not released during digestion. However, alkaline hydrolysis (the addition of water and alkali) makes niacin bioavailable (the Central American tradition of soaking grains in lime water before cooking is, thus, more than just a dietary preference as it serves an important purpose). Niacin is also synthesized from tryptophan (an essential amino acid) with moderate efficiency (60 mg of tryptophan yield 1 mg of niacin) (1).

Ready to eat cereals have the highest niacin content (up to 26 mg per serving, depending on brand).  Mushrooms, peanuts, coffee, breads and pasta all yield enough niacin to meet daily recommendations from just one serving.  Current DRI for adults is anywhere from 2 – 18 mg depending on age and gender (1).

Vitamin C

Vitamin C, aka ascorbic acid, is involved in many electron transport reactions, some of which are involved in collagen synthesis.  Collagen is a fibrous protein found primarily in connective tissue, cartilage, bone, teeth, skin and tendons.  Needless to say, it is important for maintaining healthy skin.  Lucky for us, vitamin C is abundant in most fruits and vegetables, making it relatively easy to meet daily requirements (15 to 120 mg per day depending on age and gender)(1).  In spite of this, vitamin C is one of the most commonly overconsumed supplements in the US and Canada. I can only guess that its popularity rests with the misguided belief that it prevents or cures the common cold.

Too much of this good thing may result in GI disturbances, an increased risk of some cancers (whereas, normal intake has the opposite effect), slight oxaluria, and false-positive urinary glucose test results (1).

Vitamin E

Vitamin E is the most important fat soluble antioxidant in the cell as it protects cell membranes from free radical activity.  It depends on other nutrients and enzymes to do its job, particularly copper, zinc, riboflavin and manganese.

Vitamin E is measured in terms of a-tocopherol equivalents (a-TE) of which adults need about 15 mg per day.

Tocopherols (and tocotrienols) are only synthesized in plants.  The average American, and to a lesser extent, the average Canadian, consumes most of his/her vitamin E in the form of vegetable oil even though healthier sources abound.  One ounce of almonds yields a whopping 7.33 mg (more than three times the amount found in one tablespoon of canola oil)(1).

Omega-3 fatty acids

There are three types of omega-3 fatty acids:  a-linolenic acid (ALA), eicosapentaenoic acid (EPA), and docosahexanoic acid (DHA).  Of these, ALA is an essential fatty acid (EFA), meaning it can not be synthesized by the human body, so, we must get it from food. Humans can desaturate and elongate ALA into EPA and DHA as needed, thus, it is important to include ALA in the diet on a regular basis (1).

The conversion rate of ALA to EPA and DHA is relatively low in persons who consume fish.  However, in vegetarians and vegans, the conversion rate is significantly higher, which explains the similarity of EPA and DHA levels between these groups and their meat-eating cohorts (2).  It is not necessary for vegetarians or vegans to supplement with EPA and DHA as long as they consume a healthy diet that meets their nutritional needs.  In all groups, conversion rates of ALA to EPA and DHA are higher in women (3).

EFA deficiency is rare and occurs primarily among newborns and infants.  Even in developing countries, where food is scarce, EFA deficiency is very low most likely because the most commonly consumed type of fat in such areas is usually vegetable based (vegetable fat is a good source of ALA)(4).

Water

Lastly, stay hydrated inside and out.  Rather than smother your skin with lotion (which can actually draw moisture out of the skin), use a water bottle set on “mist” instead.  Obviously, this may not be the thing to do at the office, but while you’re outdoors or at home, opt for water.  It doesn’t cost anything and it is better for your skin than most other topical applications.

REFERENCES

  1. Mahan LK, Escott-Stump S. Krause’s Food and Nutrition Therapy. MO: Saunders-Elsevier; 2008.
  2. Welch AA, Shakya-Shrestha S, Lentjes MAH, Wareham NJ, Khaw KT. Dietary intake and status of n-3 polyunsaturated fatty acids in a population of fish-eating and non-fish-eating meat-eaters, vegetarians, and vegans and the precursor-product ratio of a-linolenic acid to long-chain n-3 polyunsaturated fatty acids: results from the EPIC-Norfolk cohort. Am J Clin Nutr, 2010;92:1040-51.
  3. Burdge GC. Metabolism of a-linolenic acid in humans. Prostaglandins, leukotrienes and essential fatty acids, 2006;75(3):161-8.
  4. The Merck Manual for Health Care Professionals. Available at: http://www.merckmanuals.com/professional/nutritional_disorders/undernutrition/essential_fatty_acid_deficiency.html  Accessed: August 9, 2012.

The role of exercise in weight loss


Regular exercise can help lower the risk of cardiovascular disease, improve bone density and muscle tone, maintain a healthy weight, improve hemoglobin A1c levels, work wonders against psychological stress and anxiety, lessen arthritis pain and lower the risk of Alzheimer’s disease (1,2,3,4).  It will not, however, make you lose weight (5).

Surprised?

You shouldn’t be.  Think about it:  you can consume 500 calories (a slice of cheesecake or a 10 oz Margarita) in just a few minutes, but it takes an adult of 150 lbs over two hours of fast paced walking, or over one hour of vigorous running, to burn the same amount (1).  If you wish to burn more than 500 calories, to lose weight (as opposed to simply burning off the added calories), it will take an additional hour or so to create the desired negative balance. If the Margarita and the cheesecake slice were both a part of your after dinner indulgence, you’re looking at over 1,000 calories (making up half the daily caloric requirement for most healthy adults) that you must make disappear just to maintain your current weight.

In other words, you can’t outrun your mouth.  Or, to be fair, you can’t outrun your mouth if you have a life which includes a job, commute to work, a household to maintain, child care or other such activities as part of your daily routine.  There simply isn’t enough time in the day to compensate (with exercise) for added calories.  Maybe you can pull it off once in a while but most of the time, it’s a bit of a stretch.

If you have a reasonably healthy body mass index (BMI), regular exercise, which includes endurance as well as weight bearing activities, will go a long way toward keeping all your bits and parts in tip-top shape and your weight in a healthy range.  You will also run a significantly lower risk of gaining unwanted pounds.

You may be wondering:  if regular exercise can have such a positive effect on the body, why even mention that it falls short in terms of weight loss?

BECAUSE…

When you operate under the assumption that working hard at the gym is going to yield equally impressive results on the bathroom scale, you may be deeply disappointed with the outcome, which, in turn, may translate into disillusionment and very likely, a defeatist attitude.   “Nothing I try works” is a phrase I hear frequently from people who busted their butts at the gym for months, five days a week or more, only to see trivial changes in weight, sometimes, almost against all reason, on the plus side.  That all this work has improved their overall endurance is of little comfort when their pant/dress size has not changed for the better.

It’s not a matter of not having worked out hard enough, or long enough, or regularly enough.  It’s a matter of focusing on the wrong approach then feeling helpless when, after all the time and effort invested in it, the approach fails.

In a trial published in the Journal of American Medical Association in 2003, researchers monitored the weight fluctuations of 184 overweight women participating in various levels of physical activities over the course of 12 months (2).  The women were divided into four groups:

  • vigorous intensity / high duration exercise
  • moderate intensity / high duration exercise
  • moderate intensity / moderate duration exercise, and
  • vigorous intensity / moderate duration exercise.

All the participants benefited from varying levels of improvement in cardiovascular fitness by the end of the trial.   There was no significant difference in terms of weight loss between women at the high end of the intensity/duration exercise spectrum and those at the low end.  High intensity workouts lasting longer periods of time did not yield an advantage, in terms of weight loss, over moderate intensity and moderate duration regimens.

Similarly, the authors of a 2007 study looking at the effects of exercise on cardiovascular fitness divided 464 previously sedentary overweight and obese women participants into four groups: a no-exercise control group or one of three groups in which they expended 4, 8 or 12 calories per kilogram of weight, per week, for a period of six months by engaging in various intensities and durations of physical activity (5). Upon completion of the study, the authors found graded dose response changes in heart fitness across all levels of exercise, but no significant changes in weight.  Exercise alone, regardless of intensity or duration, did not amount to a hill of beans in terms of weight loss, even when routines were maintained for as long as six months.

Several factors account for these somewhat counterintuitive outcomes including increased hunger (and, thus, food consumption) as a result of vigorous exercise, a tendency for people to relax their calorie counting on the days they work out (or they think they can indulge today because they are going to work out tomorrow), the notion that they deserve a reward (read: chocolate lava cake) for all the hard work they’ve completed, and a host of other physiological and psychological factors.  These studies are mere drops in a virtual ocean of evidence that weight loss occurs in the wake of dietary changes, rather than as a result of vigorous exercise routines (6).  “Ah, but muscle weighs more than fat!” you might say, “so, no change in weight doesn’t necessarily mean no change in body size!”  True, but the overwhelming evidence suggests the lack of improvement is not specific to weight, but to overall measurements as well, whenever exercise routines are the only intervention. If study participants ended the trials several dress sizes smaller but weighing the same, there would be no point to having this discussion.

That being said, regular physical activity not only helps keep the weight off, but helps protect against a great number of diseases of affluence (cardiovascular disease, diabetes).  As such, it is an important part of any healthy lifestyle (7,8).

If you are trying to lose weight, it is important to focus on making permanent changes  to your dietary habits.  Popular fad diets don’t work in the long run and exercise alone is not going to help you reach your goals.  There is a sense of helplessness that accompanies the generally disappointing outcomes of making uninformed weight loss regimen choices.  You  may end up feeling as though nothing you try works, therefore, there’s no sense in trying.

A healthy diet that focuses on plant based foods goes a long way toward normalizing caloric intake, body weight and metabolic markers with or without the help of an exercise regimen (9,10).  Talk to a dietitian and/or qualified nutrition counsellor and get the help you need to make permanent lifestyle changes.  Some gyms have dietitians on staff whose services are included in your gym membership.  Work on your dietary habits/choices, and the rest will follow.  It is easier and healthier to watch your caloric intake than to fight an uphill battle while trying to  compensate for added calories by working out.

REFERENCES

  1. Centers for Disease Control and Prevention, Division of physical activity and obesity.  Why is physical activity important? 2012. Available at:  http://www.cdc.gov/healthyweight/physical_activity/  Accessed June 2, 2012.
  2. Jakicic JM, Marcus BH, Gallagher KI, Napolitano M, Lang W.  Effect of exercise duration and intensity on weight loss in overweight, sedentary women – a randomized trial.  JAMA 2003; 290(10): 1323-1330.
  3. Church TS, et al. Effects of aerobic and resistance training on hemoglobin A1c levels in patients with type 2 diabetes.  JAMA 2010; 304(20): 2253-2262.
  4. Scarmeas N, et al. Physical activity, diet, and risk of Alzheimer’s disease.  JAMA 2009; 302(6): 627-637.
  5. Church TS, Earnest CP, Skinner JS, Blair SN. Effects of different doses of physical activity on cardiorespiratory fitness among sedentary overweight or obese postmenopausal women with elevated blood pressure. JAMA 2007; 297(19):2081-2091.
  6. Rock CL, Flatt SW, Sherwood NE, Karanja N, Pakis B, Thomson CA.  Effect of a free prepared meal and incentivized weight loss program on weight loss and weight loss maintenance in obese and overweight women.  JAMA 2010; 304(16): 1803-1811.
  7. Hankinson AL, et al.  Maintaining a high physical activity level over 20 years and weight gain. JAMA 2010; 304(23): 2603-2610.
  8. Lee I, Djousse L, Sesso HD, Wang L, Buring JE.  Physical activity and weight gain prevention.  JAMA 2010; 303(12): 1173-1179.
  9. Newby PK, Tucker KL, Wolk A. Risk of overweight and obesity among semivegetarian, lactovegetarian, and vegan women. AJCN, 2005; 81: 1267-74.
  10. Vergnaud A, et al.  Meat consumption and prospective weight change in participants of the EPIC-PANACEA study.  AJCN 2010; 92: 398-407.

To spit or not to spit…


Candida albicans is a fungus which, along with thousands of other species of fungi and bacteria, lives symbiotically within the human body (1).  Proper Th1 (a type of lymphocyte) response of the immune system keeps its numbers in check as it goes about its daily business rendering it virtually incapable of producing infection or disease in the healthy host (1).  In immune suppressed persons, such as HIV patients or persons taking immunosuppressant medications, invasive growth may occur.

Candidal infections usually take over warm and moist areas of the body such as underarms, oral and genital areas.  Itching and irritation accompanied by rashes, blisters or painful cracks in the corners of the mouth (in the case of oral thrush), as well as discharge that resembles cottage cheese (in the case of vaginal infection) are the most common signs (2).  In rare cases, usually as a result of significantly depressed immune system function, the infection may spread to other areas of the body, and can affect the organs and blood (2). In such cases, symptoms are more severe, usually painful, with or without fever, and, if the infection is in the blood and spreads to the brain it can cause significant disruptions in mental function. Infections of this magnitude are usually life threatening (2).

Candidiasis affecting the skin, oral and/or genital cavities is treated with over the counter or prescription medications for a few days or a couple of weeks, whereas, infections affecting organs and the blood require hospitalization and intravenous medications as they can be fatal.

Infections affecting organs and the blood (aka “systemic infections”) occur primarily in hospital settings among patients undergoing immune system suppression (usually in the wake of transplant surgery or auto-immune disease/disorder treatment) (3).  The infection tends to recur several times during the first six months following surgery or immune system suppression treatment (4).  Its signs and symptoms are generally severe and require aggressive interventions.   Even so, death occurs in more than 1 out of 2 infected patients (3).  The good news is that infection rates hover around 2.9 per 100,000 people in Canada and anywhere between 6 and 10 per 100,000 people in the USA (depending on geographical region studied), making systemic candidiasis infections relatively rare (3).

ALTERNATIVE MEDICINE TAKE ON THIS

A surprising number of websites and their authors (who often also publish books on the subject or sell their own brands of remedies) may tell you that C. albicans is the leading cause of afflictions too many to list here, ranging from general fatigue and brain fog to asthma and obesity.  It takes over the body, organs, and blood, they claim, but keeps its population in check somehow, thus, remaining undetected by conventional methods, because, they say, physicians do not, or pretend to not, have the necessary technology.  However, they tell us that if we spit in a glass of water and watch what the saliva does over the course of 20 minutes, we can detect the infection ourselves. Of course, everyone’s saliva is going to do something similar (or exactly the same) to what is described in this so-called “test”, rendering it less than useless.

Whatever your symptoms, C. albicans is generally considered to be the main culprit and changing your diet (which almost always includes taking whatever supplement the website author is peddling) is the remedy of choice.  Science based medicine is often seen as having an agenda that keeps it from diagnosing and treating the infection.  Assuming the diagnosis and treatment would involve trading money for services / tests / medications rendered, this agenda must involve something far more valuable than mere dollars.  Whatever it is, its value exceeds the potential windfall that treating nearly 90% of the population (the number of people afflicted by C. albicans systemic infection, according to the “treatment” promoting websites – a far cry from the less than 0.0003% actually documented by the Canadian Journal of Infectious Diseases) would provide (3).

REALITY CHECK

C. albicans, in the absence of a normal immune system response, will do what any pathogen will do:  it will spread relatively quickly until something stops it.  That something is usually medical intervention that restores immune system function and/or attacks the fungus itself.  When no intervention takes place, infection spreads unchecked and death soon occurs.  This process does not take years- or decades-worth of suffering from nebulous afflictions.  An out of control infection acts relatively quickly, its signs and symptoms don’t beat around the bush, and even with the best of care and prompt intervention, odds of survival are not good.

REFERENCES

  1. Kosonen J, Rantala A, Little CH, Lintu P, Harjamaki PR, Georgiou GM, Cone RE, Savolainen J.  Increased levels of Candida albicans Mannan-specific T-cell-derived antigen binding molecules in patients with invasive candidiasis. Clinical and Vaccine Immunology, 2006;13(4):467-474.
  2. Molero G, Diez-Orejas R, Navarro-Garcia F, Monteoliva L, Pla J, Gil C, Sanchez-Perez M, Nombela C.  Candida albicans: genetics, dimorphism and pathoginicity. Internatl Microbiol,  1998;1:95-106.
  3. Bow EJ, Evans G, Fuller J, et al.  Canadian clinical practice guidelines for invasive candidiasis in adults. Can J Infect Dis Med Microbiol, 2010;21(4):e122-e150.
  4. Danovich GM, Handbook of Kidney Transplantation, Philadelphia, PA: Lippincott Williams & Wilkins; 2010:269.

Protein powders and shakes


A few decades ago, protein powders used to lurk in gyms and so-called “health” food stores. They were stacked neatly on shelves amidst colourful ads that lured would-be buyers with images of famous bodybuilders and athletes whose physiques few of them would ever match. In those days, their primary targets were body builders. Claims varied, but most brands promised increased muscle gain that, according to the ads, run of the mill, food derived protein could not possibly provide.

Today, protein powders have escaped the confines of gyms and health food stores and have become ubiquitous on food market shelves, in pharmacies, and virtually anyplace else food, supplements, or pharmaceuticals are sold. Their user base has changed dramatically to include athletes (professional sports people who are not bodybuilders), recreational athletes (sport hobbyists and/or fitness enthusiasts), and lifestyle users (consumers who think protein powders are healthy snacks and/or will help them lose weight)(1). Vegetarian and vegan consumers of protein powders tend to fall in the last two categories and are likely to believe the powders, or other similar supplements, are necessary to meet their daily protein needs. Some users claim they “feel better” and have more energy when they consume protein powders, while others simply believe that without their daily dosage, their muscles would vanish into thin air.

ENERGY

“The extra protein gives me energy!” is a claim I hear surprisingly often. It is surprising because protein is a lousy source of energy. It is a last resort the body will tap when it runs out of its preferred fuel (particularly during exercise): glycogen (aka stored carbohydrate)(2). You may have heard of athletes engaging in something called “carb-loading” before events. This consists of consuming a higher ratio of carbohydrates to help the body handle the energy requirements of extended activity, particularly if the event involves increasing pace and effort to beat the competition (3). The more intense the exercise, the more carbohydrate the body burns. Consuming carbs before and during exercise helps athletes keep up the pace. In fact, a high carbohydrate diet increases endurance time three-fold when compared to a high protein diet (3). Once glycogen runs out, so does your energy and ability to keep going. Similarly, failing to replenish your glycogen stores after exercise, will impair your ability to recover and achieve your training goals.

During periods of extended low intensity exercise, such as walking, fat becomes an important source of energy, more so if you engage in regular exercise. The more you train, the more your body uses fat for energy when you are resting or performing less strenuous activities. As you pick up the pace, your body switches back to using glycogen.

Image source:  McArdle et al. – Sports and Exercise Nutrition, 3rd Ed., Chapter 5, Macronutrient Metabolism in Exercise and Training, page 157 (3).

In a nutshell, if you’re looking for extra energy, put away the protein powder and have some healthy carbs instead.

MORE MUSCLE

Muscle growth occurs as the result of training, not from the overconsumption of protein. There is only so much protein the body will use before it stores the excess away. Protein powders are digested faster than food derived protein, making protein available for muscle repair in a more expedited manner. “Aha!” you might say, “so, they ARE good for something!” Well, not really. In the long run, the end result is about the same – except, perhaps, for your wallet.

Studies looking at the effects of supplementation and strength training combined show insignificant or no difference between placebo and control groups (2,4).  In their 2009 joint position paper on nutrition and athletic performance, the American Dietetic Association, Dietitians of Canada, and the American College of Sports Medicine concluded the following (5):

“Current evidence indicates that protein and amino acid supplements are no more or no less effective than food when energy is adequate for gaining lean body mass. Although widely used, protein powders and amino acid supplements are a potential source for illegal substances such as nandrolone, which may not be listed on the ingredient label.”

In other words, as long as you meet your body’s protein requirements, it doesn’t make much difference if you’re getting the protein fast, from a powder, or slower, from food. What matters most is timing (6). Consumption of protein and carbohydrate containing foods immediately after training is far more important if you want to see results. The sooner you eat, the better. Letting as little as two hours pass after a workout without eating will lead to a lot of disappointment on your part if you’re looking to build muscle mass (7).

PRE-, DURING and POST-EXERCISE NUTRITION

For best results in terms of performance and overall health (the latter is sometimes overlooked when people consider a plan of action in the short term), remember that supplements are not a replacement for healthy food choices.

Eat breakfast, consume the appropriate amount of calories for your body (don’t forget to eat healthy fats), stay hydrated and be sure to eat before and after exercise. If you like coffee or tea, you may be surprised to know that caffeine is an effective ergogenic aid, particularly in racing events, but also in short term, high intensity events, if consumed one hour before exercise (8,9). If you’ve given up coffee and tea because you think it will hinder your performance, dehydrate you, or interfere with electrolyte balance, you may want to reconsider your choice (8,9,10).

While studies on the effects of protein restriction on performance have yielded inconclusive results, the same is not true when it comes to carbohydrate restriction which has been shown to be detrimental (11,12). The importance of carbohydrate consumption after workouts can not be overemphasized. The aforementioned position paper on nutrition and athletic performance provides the following guidelines for performance athletes (5):

  • Carbohydrate recommendations for athletes range from 6-10 g/kg (2.7-4.5 g/lb) body weight per day depending on extent and duration of exertion (5).
  • Protein recommendations for endurance and strength trained athletes range from 1.2-1.7 g/kg (0.5-0.8 g/lb) body weight per day. The authors stress that food sources can easily meet requirements and supplementation is not necessary (5).
  • Fat intake should range from 20%-35% of total energy intake. Note that consuming less than this will not improve performance (5).
  • Before exercise, a meal or snack “should provide sufficient fluid to maintain hydration, be relatively low in fat and fiber to facilitate gastric emptying and minimize gastrointestinal distress, be relatively high in carbohydrate to maximize maintenance of blood glucose, be moderate in protein, be composed of familiar foods, and be well tolerated by the athlete.”(5)
  • During exercise, it is important to replace fluid losses and “provide carbohydrates (approximately 30-60 g per hour) for maintenance of blood glucose levels.”(5)
  • After exercise, “a carbohydrate intake of ~1.0-1.5 g/kg (0.5-0.7 g/lb) body weight during the first 30 minutes and again every 2 hours for 4 to 6 hours will be adequate to replace glycogen stores. Protein consumed after exercise will provide amino acids for building and repair of muscle tissue.”(5)

To put things in perspective, let’s consider the nutritional requirements of a 160 pound male professional soccer player:

Calories: approx. 4,000 per day
Protein: approx. 110 grams per day, or 11% of daily calories
Carbs: approx. 640 grams per day, or 64% of daily calories
Healthy Fats: approx. 111 grams per day, or 25% of daily calories

Notice that although 110 grams of protein per day represents quite a bit more than the amount of protein recommended for weekend athletes or sedentary persons, this amount does not represent a higher percentage of daily calories. In other words, it is not added (or supplemented) protein.

BOTTOM LINE

If the only way you are meeting your protein requirements is by supplementing with protein powders, there is something wrong with your diet. It should not be difficult to meet the recommended 10% to 15% of your daily calories in the form of protein. In fact, I would be very surprised if this is the case, given the abundance of food varieties available in North America. In the unlikely event you are not getting enough protein or the necessary ratios of essential amino acids, tweaking your diet will be better for your health (and for your wallet) in the long run than starting a protein supplementation habit.

REFERENCES

  1. Overview of the Sports Nutrition Market—Food, Beverages and Supplements, 2010; ISSN 1920-6593 Market Analysis Report, AAFC No. 10745E.
  2. Maughan RJ. Nutrition in Sport – Volume VII of the Encyclopedia of Sports Medicine. MA: Blackwell Science, Inc.; 2000.
  3. McArdle WD, Katch FI, Katch VL. Sports and Exercise Nutrition, 3rd Ed. MD: Lippincott Williams & Wilkins; 2009.
  4. Williams AG, van den Oord M, Sharma A, Jones DA. Is glucose/amino acid supplementation after exercise an aid to strength training? Br J Sports Med, 2001;35:109-113.
  5. Nutrition and athletic performance. Journal of the American Dietetic Association, 2009; 109(3):509-527.
  6. Poole C, Wilborn C, Taylor L, Kerksick C. The role of post-exercise nutrient administration on muscle protein synthesis and glycogen synthesis. Journal of Sports Science and Medicine, 2010;9:354-363.
  7. van Essen M, Gibala MJ. Failure of protein to improve time trial performance when added to a sports drink. Med Sci Sports Exerc. 2006;38:1476-1483.
  8. Cox GR, Desbrow B, Montgomery PG, Anderson ME, Bruce CR, Macrides TA, Martin DT, Moquin A, Roberts A, Hawley JA, Burke LM. Effect of different protocols of caffeine intake on metabolism and endurance performance. Journal of Applied Physiology, 2002:93:990-999.
  9. Paluska SA. Caffeine and exercise. Current Sports Medicine Reports, 2003;2:213-219.
  10. Bell DG, McLellan TM. Effect of repeated caffeine ingestion on repeated exhaustive exercise endurance.  Medicine & Science in Sports & Exercise, 2003; DOI: 10.1249/01.MSS.0000079071.92647.F2
  11. Knechtle B, Knechtle P, Mrazek C, Senn O, Rosemann T, Imoberdorf R, Ballmer P. No effect of short-term amino acid supplementation on variables related to skeletal muscle damage in 100 km ultra-runners – a randomized controlled trial. Journal of the International Society of Sports Nutrition, 2011;8:6.
  12. Ivy JL, Res PT, Sprague RC, Widzer MO. Effect of a carbohydrate-protein supple- ment on endurance performance during ex- ercise of varying intensity. Int J Sport Nutr Exerc Metab. 2003;13:382-395.

Do detox plans work?


Short answer? No.

“But I feel better after a detox!” you might say.

Of course you do. You’ve avoided junk food and other unhealthy foods for several days or weeks. Your body is thrilled. This does not mean you’ve rid yourself of unwanted substances.

Detox claims

Various so-called “detox” products and diets claim to accomplish many different things (sometimes all at once), the most common of which tend to revolve around boosting the immune system, increasing energy, and/or promoting weight loss. The one claim they all have in common, as evidenced by the presence of the words “detox” and/or “cleanse” in their selected names, is that such diets or products will rid your body of some (or all) toxins that have accumulated in various tissues over the years.

The product being touted, be it a pill, shake, drink, diet, skin pad, or electronic contraption, is supposed to locate the silent killers in your body and escort them out via urine, faeces, or sweat. Together, these products and services amount to a multibillion dollar industry worldwide that dupes people into spending money that would be better spent on learning how to eat healthy, well rounded diets and engaging in more physical activities on a regular basis.

Dosage

We inhale, ingest, and absorb (through the skin) hundreds of different chemicals every day. Whether or not these chemicals are toxic to us depends on dosage, either at the time of exposure, or after years of accumulation in the body. I can’t stress this point enough: dosage is everything and any chemical, natural or man made, from ascorbic acid to zinc, can be toxic if enough of it is absorbed or accumulated. Heck, water can kill you if you drink too much at once.

It is very unlikely that any food item purchased in industrialized nations such as the US and Canada contains toxic doses of any chemical given that our food supply is fairly well controlled. Sure, there may be a mishap now and then, but this is the exception, not the rule. Thus, it is the slow accumulation of small amounts of unwanted chemicals in the body that detox and cleansing programs usually target, but fail to actually remove.

What happens to all the unwanted stuff we take in?

Except in cases of overdose (poisoning), harmful chemicals are usually blocked from harming the body by natural barriers such as the gastrointestinal (GI) system, lungs, and skin (1). Those which sometimes break through these barriers are excreted with the help of the liver, kidneys, and lymphatic system (more than half the tissue of which surrounds the digestive tract)(1). These systems work together to eliminate threats to the body and do a great job of it in the absence of disease – if cirrhosis is present, for example, the liver will have a hard time doing its job. Thus, unless you have been diagnosed with something which directly involves these systems, most substances that pose a threat to your health will be eliminated with or without any added help (1).

Although some of the chemicals commonly used to control pests in our food supply stick around the body for a while, they generally do so in insignificant doses, or for less time than it is necessary for them to cause significant harm. There are some exceptions, of course, such as persistent organic pollutants (POPs). You may have heard of POPs as the “dirty dozen”. These include DDT and other chemicals that were predominantly used in manufacturing of various items, as well as in food production (particularly as pesticides), a few decades ago when we didn’t know any better. Their use has been outlawed in most countries, with some limited use (such as the use of DDT to fight malaria) still allowed in certain circumstances. Although they are no longer in use today, they are still around in our environment, left over from their heyday. If present in your body, no diet, shake, pill, foot pad, foot bath, colon irrigation, or any other means of so-called “detoxification” method is going to help you rid yourself of them. You simply have to wait them out and hope they aren’t doing too much damage while they’re camping out in your body. Most will, eventually, surpass their respective points of half-life and begin to slowly disappear on their own before you do.

If you are concerned about the presence of pesticides, herbicides, fungicides, fumigants, hormonal growth promoters, anthelmintics (used to control internal parasites in farm animals), and antibiotics in your food, then, a change in mind-set is needed: rather than looking for ways to “cleanse” yourself of these things, look, instead, for ways to avoid exposure to them in the first place. If you smoke and agree that smoking is bad for your health, do you look for things that can help your lungs cope with your habit, or do you concentrate instead on ways to help yourself quit smoking?

Which foods contain the most unwanted substances?

Animal foods. If you’re veg*an, you have very little to worry about since the amount of unwanted chemicals you ingest by consuming non-organic, conventional plant foods pales in comparison to what you would be ingesting if you were eating animals.

Animals are higher on the food chain than plants and their products. The higher up the food chain we go, the higher the concentrations of unwanted substances we find. For instance, predatory fish (i.e. tuna, salmon, sword fish) have higher concentrations of mercury in their flesh than plant eaters (i.e. sardines). Such harmful substances accumulate primarily in muscle tissue and organs (some set up camp in fatty tissues). The less animals you eat, the less likely it is you will ingest and accumulate questionable chemicals in meaningful amounts. Of course, regardless of dietary choices, we must still breathe and live surrounded by plastics and other man made materials, so, resistance to exposure is… well… futile.

What about the sludge sticking to the inside of my intestines? Will diet or colonic irrigation get rid of that?

There is no sludge. I will happily state otherwise (and eat my husband’s hat) if anyone can show me footage from a colonoscopy that shows this sludge hanging out inside the colon or anywhere else in the GI tract for that matter.

How can I boost or stimulate my liver, kidneys, lymphatic system?

You can’t. You can avoid taxing them unnecessarily (for instance, don’t drink alcohol to excess), but you can’t “boost” them into performing beyond their limitations. If their performance is diminished, medical intervention is very likely needed, since this implies something is wrong (kidney disease, liver disease).

Bottom line

Don’t waste your money and don’t torture yourself with bad tasting concoctions or invasive and uncomfortable procedures. Your body “detoxes” itself just fine and the stuff it can’t get rid of on its own is not going to be removed by special diets, products, or visits to the local colonic irrigation shop. Avoid exposure within reason, eat less, or no animal products, and save the stress for things that truly are worth worrying about… like healthcare reform.

References

  1. Mahan LK, Escott-Stump S. Krause’s Food and Nutrition Therapy. MO: Saunders-Elsevier; 2008.
  2. Lasky T, Sun W, Kadry A, Hoffman MK. Mean total arsenic concentrations in chicken 1989 – 2000 and estimated exposures for consumers of chicken. Environmental Health Perspectives, 2004:112(1):18-21.
  3. Leeman WR, Van Den Berg KJ, Houben GF. Transfer of chemicals from feed to animal products: the use of transfer factors in risk assessment. Food Additives and Contaminants, 2007:24(1):1-13.

Physician nutrition training – throwing the baby out with the bathwater


It is a little known fact that most medical doctors (MD’s) in the United States (and probably Canada) know little more about nutrition than the average person, regardless of the latter’s occupation.  During the 70's – 80's, a handful of medical schools provided some semblance of nutrition training.  In the 90's, as the roles of diet and lifestyle in the development and treatment of disease became more known, the number of medical schools providing nutrition education to would-be physicians went up slightly.  Today, that number is back down to pre-1980 levels, with most schools failing to provide the recommended 25 hours of nutrition training (which is comparable to a three day workshop on the subject (1,2,3).

From:  Nutrition education in US medical schools: latest update of a national survey. Academic Medicine (5).

This would be a non-issue if family physicians, pediatricians, and a host of other specialists would refrain from giving nutrition advice and, instead, refer their patients to registered dieticians.  However, a survey of primary care practitioners reveals that over two thirds of respondents provide dietary counseling to patients, in spite of glaring gaps in knowledge and training of the practitioners themselves (4).

In February 2011, in California, a handful of physicians gave testimony to support the introduction of a senate bill which would require that medical doctors complete seven continuing education credits (CEC’s), on nutrition and lifestyle behavior, by the year 2016.  In May of the same year, the bill passed, but not before the required seven credits were crossed off (what is left of the bill can be viewed here).  A shame, one might say, given the astronomical amount of tax and insurance dollars spent every year on lifestyle diseases (e.g. heart disease, stroke, type 2 diabetes, and a number of cancers).


But is increasing nutrition education of future and/or practicing physicians an appropriate solution? At a time when med student and/or physician burnout rates are at an all time high, probably not.  They have enough on their collective plate as it is.

BECOMING A PHYSICIAN

Requirements:

  • 4 years of university to earn a BS or BA with emphasis on basic science +
  • 4 years of medical school to earn a medical degree (MD) +
  • 3 – 7 years of graduate medical education which involves entering a residency program (e.g. 3 years for family practice, 5 years for general surgery, etc.) +
  • 1 – 3 years in a fellowship program should the new MD desire to become highly specialized in a particular field such as oncology or gastroenterlogy +
  • Passing the licensure exam and recertification exams on a regular basis after that +
  • Ongoing CECs from various medical arenas.

All of this amounts to barely enough time to cover the required material.

IS THE ADDITION OF NUTRITION TRAINING REALISTIC?

When and how, in scaling that mountain of education and clinical practice, is a future physician supposed to include the amount of nutrition education that would place him/her on par with a registered dietitian or, harder still, a CNS?  The first requires a four year bachelor’s degree in dietetics, of which 2.5 years concentrate on nutrition topics alone, and six months of clinical practice.  Adding nearly three years of nutrition education to an already extended MD program is absurd.  More so if trying to achieve a CNS level of education in this field, which requires a graduate degree in nutrition and 2,000 hours of practice.  It can be done, as some MDs sporting CNS credentials will attest, but how necessary is it to go to such great lengths, when registered/certified nutrition professionals are but a referral away?

On the other hand, simply taking basic nutrition courses over the course of those 11+ years of schooling (which, some medical schools do provide) or earning the recommended CECs in this domain after becoming a physician, doesn’t even begin to cover the tip of the nutrition information iceberg that might be of some use in terms of chronic disease or developmental nutrition (e.g. paediatrics, gerontology) management. Moreover, given that most physicians are spread too thin and can only spend a short amount of time on individual patient visits, how much quality nutrition advice can they provide under such circumstances? My guess is not much beyond that of which most patients are already aware. Nutrition advice is joined at the hip with behavioral modification counseling, both of which take time – and time is a luxury most physicians can not afford these days.

REFERRALS TO NUTRITION PROFESSIONALS

There isn’t enough time, or money, for that matter, to properly educate physicians about nutrition to the extent that they may counsel patients beyond what the patients already know.  That’s why the medical community saw fit to train nutrition professionals, such as RDs and CNSs, instead.  Most, however, rarely see a referral outside hospital walls.

The answer is not additional nutrition coursework for physicians. Instead, let’s introduce mandatory medical school courses and CECs for practicing physicians on how to recognize those instances in which referrals to nutrition specialists are necessary.  Furthermore, regulations should be in place requiring physicians to make dietician or CNS referrals instead of offering what amounts to sub-par, and often times erroneous, nutrition advice.

BABY, BATHWATER

This lack of initiative in terms of recognizing the need for, and providing, referrals has led some people (particularly those who tend to mistrust the medical community as a whole) to discount science based medicine altogether and jump ship to the alternative medicine side, in some cases with disastrous results.

In doing so, they are throwing the baby out with the bathwater.  Ditching one’s family physician over something s/he is not supposed to know about in the first place does not make a whole lot of sense, but to some patients it seems like the right thing to do when faced with a physician who is handing out incorrect information about nutrition.  They assume the doc may advise them poorly even when dealing in his/her own area of expertise.  Sometimes, this line of thought evolves into conspiracy theories about the medical profession that are well into tin hat territory.

BOTTOM LINE

Let physicians do what they are trained to do, but require they complete coursework on how to recognize those instances in which nutrition referrals are necessary, as well as any psychological factors that may keep referrals from happening in the first place.

REFERENCES

  1. Bruer RA, Schmidt RE, Davis H. Nutrition counselling – should physicians guide their patients? Am J Prev Med. 1994;10(5):308-11.
  2. Adams KM, Linderll KC, Kohlmeier M, Zeisel SH. Status of nutrition education in medical schools. Am J Clin Nutr, 2006;83(4):941S-944S.
  3. Flynn M, Sciamanna C, Vigilante K. Inadequate physician knowledge of the effects of diet on blood lipids and lipoproteins. Nutrition Journal, 2003;2:19.
  4. Kushner, R.F., Barriers to providing nutrition counselling by physicians: a survey of primary care practitioners, Preventive Medicine, 1995 Nov;24(6):546-52.
  5. Adams KM, Kohlmeier M, Zeisel SH.  Nutrition education in US medical schools: latest update of a national survey. Academic Medicine, 2010;85(9):1537-1542.

Lab meat – a healthier alternative?


Over the last decade, news stories featuring the advent of lab meat technology and its pink and pasty results have been peppering the virtual landscape, showing up in places like NBC, Forbes and a number of other news outlets.  It seems the lab grown burger is now ready for production, and, at some point in the future, for sale in your local stores and restaurants.  It has been touted as a way to improve diets in emerging economies by introducing cheaply produced meat on their markets, but is it any healthier than its traditionally produced counterpart?

WHAT’S IN IT?

Lab grown meat is cultivated from animal cells, so, in the case of hamburger, the cells come from a cow.  Unlike conventional meat, lab meat can be produced with far less fat, but not without the use of growth hormones, seeing how it has to grow quickly in order to be profitable (1).  Since lab meat is real animal flesh, haem iron is present, as is the increased risk for cardiovascular disease and bowel cancer it represents (see my earlier post on iron).  Producers are going out of their way to make sure this type of iron is included in the final product since they see any deviation from the real thing as a downside in terms of marketing (1).

No mention has been made regarding the presence of neu5gc in non-human mammals, nor of any possibility that lab meat can be produced without it (2). This is unfortunate given this molecule’s effects on the human body include a chronic state of low grade inflammation (for as long as meat and dairy are consumed),   involvement in arteriosclerosis, cancer progression, and the facilitation of hemolytic ureic syndrome, among other things (3,4,5). “Neu5Gc is present both in endothelium overlying plaques and in subendothelial regions, providing multiple pathways for accelerating inflammation” in arteriosclerosis (3).

Neu5gc is a sialic acid present on cell surfaces of all mammals with the exception of humans. We do not produce it, but we have antibodies which, to the surprise of its discoverers, are unable to fight it off completely (4).  When found setting up camp in our bodies it is there because we ingested it (5).  It is the only known non-human dietary molecule that becomes incorporated onto human cell surfaces  even after the immune system responds against it.  The immune response to the ever-present molecule sets off a repeating cycle wherein the resulting chronic inflammation helps tumours grow even as antibody response is boosted.  But it isn’t all bad news. All this research into what is now known as the “meat eater’s molecule” has yielded one surprising result:  aggressively boosting antibody response against it may help fight the tumours it helps produce in the first place (4).  Of course, staying away from eating the meat of four legged creatures, natural or lab made, would be the easiest way to avoid this whole cycle.

Lastly, animal protein is animal protein regardless of whether it comes from a slaughtered animal or artificially maintained animal cells.  Recent evidence suggests animal protein may increase cardiovascular disease risk in healthy men after controlling for confounders such as saturated fat (7).  Potential manufacturers have considered introducing plant protein into their final product but canned the idea as fears this may raise allergy issues for consumers prevailed (1).

BOTTOM LINE

Lab meat will give the environment and farm animals a break, to be sure, but, aside from containing less fat than conventional animal products, daily consumption will yield many of the same risk factors as conventional, organic, or wild caught meats.

REFERENCES

  1. Datar I, Betti M. Possibilities for an in vitro meat production system.  Innovative Food Science and Emerging Technologies, 2010;11:13-22.
  2. Varki A. Uniquely human evolution of silica acid genetics and biology. PNAS, 2010;107(2):8939-8946.
  3. Pham T, Gregg CJ, Karp F, Chow R, Padler-Karavani V, Cao H, Chen X, Witzum JL, Varki N, Varki A.  Evidence for a novel human-specific xeno-auto-antibody response against vascular endothelium. Blood, 2009;114(25):5225-35.
  4. Hedlund M, Padler-Karavani V, Varki N, Varki A. Evidence for a human-specific mechanism for diet and antibody-mediated inflammation in carcinoma progression.  PNAS, 2008;105(48):18936-41.
  5. Lofling JC, Paton AW, Varki NM, Paton JC, Varki A.  A dietary non-human silica acid may facilitate hemolytic-uremic syndrome.  Kidney Int., 2009;76(2):140-144.
  6. Varki N, Varki A. Diversity in cell surface silica acid presentations: implications for biology and disease.  Laboratory Investigation, 2007;87:851-7.
  7. Preis SR, Stampfer MJ, Spiegelman D, Willett WC, Rimm EB.  Dietary protein and risk of ischemic heart disease in middle-aged men. Am J Clin Nutr, 2010;92:1265-72.

The protein myth


There are a number of food myths currently in circulation, some of which have been around for decades.  They generally revolve around particular micro- and macro-nutrients, their sources, and/or their imaginary abilities to cure us of all sorts of ailments ranging from the common cold to cancer.  Among these, we find the “protein myth” which, in a nutshell, states that protein from animal foods is superior because it contains all essential amino acids.

WHAT ARE PROTEINS?

Proteins are the most complex of the three macro-nutrients. They are composed of long chains of amino acids and, in some cases, include other components that are strung together in complicated formations consisting of carbon, hydrogen, oxygen, and nitrogen.  Every cell in the human body contains protein. It is a major part of the skin, muscles, organs, glands and all body fluids, except bile and urine.  Proteins in the body act as enzymes (catalysts), messengers (hormones), structural elements, immunoprotectors (immunoglobulins or antibodies), transporters, buffers, fluid balancers, or receptors on cell surfaces.  They also play a role in cell adhesion, storage of minerals in the body, and as conjugated proteins (glycoproteins) (1).

Three types of amino acids fold into acid chains to form proteins.  They are:

Essential or indispensable amino acids

  • Essential amino acids cannot be made by the body. As a result, they must come from the foods we eat.
  • They are: histidine (infants only), isoleucine, leucine, lysine, methionine, phenylalanine, threonine, tryptophan, and valine.

Nonessential amino acids

  • “Nonessential” means that our bodies produce an amino acid, even if we don’t get it from the foods we eat.
  • They include: alanine, asparagine, aspartic acid, and glutamic acid.

Conditional amino acids

  • Conditional amino acids are usually not essential, except in times of illness and stress, and are made in the body.
  • They include: arginine, cysteine, glutamine, tyrosine, glycine, ornithine, proline, and serine.

The chains are held together by hydrogen bonds, and, sometimes, by ionic bonds, depending on how the chain is folded (i.e. positive and negative ions face each other), by van deer Waals dispersion forces, or by sulphur bridges.

HOW MUCH PROTEIN DO WE NEED?

Although the human body contains a large amount of protein, it does not need to consume large amounts to maintain itself.  According to the World Health Organization (WHO), the average adult needs to consume approximately 60 grams of protein per day (0.8 grams per kilogram of body weight or 10 to 15% of total calories (assuming daily caloric needs are met) (2). As far as amino acids are concerned, we do not need to consume all of the essential amino acids at every meal, but getting a balance of them over the course of a 24 to 48 hour period is important.

PLANT vs ANIMAL PROTEIN

Plants produce/contain all of the essential amino acids because they can not get them from their environment by consuming other living organisms (the exception being carnivorous plants such as the Venus Fly plant which “eats” insects).  The amino acid profile of each plant varies – for instance, beans are high in lysine, while grains are low in it, but both contain it.  There is no such thing as a plant that lacks one or more amino acids (3). It is surprising, and disappointing, to see that, in spite of all we have learned about nutrition in the past couple of decades, the notion that plants lack certain amino acids persists (often in places one would least expect to find such false assumptions).

It is not necessary to consume animal products to meet essential amino acid needs, as long as the diet includes plant foods from all the food groups and caloric needs are met. Keep in mind, there is enough protein in plants to grow elephants and Panda bears. Contrary to popular belief, animals don’t make the essential amino acids we require. They ingest them by consuming plants (or one another).

The terms “complete” and “incomplete” proteins, when referring to protein foods, are no longer considered accurate or useful, and educators are encouraged to abstain from using them in the classroom (4).  Such terms are misleading and can create confusion since “incomplete” proteins are often described as “lacking” one or more essential amino acids.  This, of course, is not true and can be easily verified by looking up the amino acid content of plant foods using the USDA National Agricultural Library Nutrient Database.

From Young and Pellet’s review on plant proteins in relation to human protein and amino acid nutrition – click on image for larger version (5).

Should you, for whatever reason, want to include so-called “complete” proteins in one single meal, you may consume any of the following:

  • Soy, or
  • Eggs, or
  • Dairy, or
  • Legumes + Grains (e.g. peanut butter sandwich, burrito), or
  • Legumes + Nuts  (e.g. lentils and cashews), or
  • Legumes + Seeds (e.g. hummus)

In a review of plant based diets and their adequacy in meeting amino acid needs, Millward concludes:  “it is clear that meat-free, largely plant-based diets available in developed countries can supply protein in the amount and quality adequate for all ages” (6).  Similarly, the American Dietetic Association (ADA), in its position paper on vegetarian diets, states the following:  “Plant protein can meet protein requirements when a variety of plant foods is consumed and energy needs are met. Research indicates that an assortment of plant foods eaten over the course of a day can provide all essential amino acids and ensure adequate nitrogen retention and use in healthy adults; thus, complementary proteins do not need to be consumed at the same meal(7).

In the same paper, the ADA further adds:  “Vegetarian diets are often associated with a number of health advantages, including lower blood cholesterol levels, lower risk of heart disease, lower blood pressure levels, and lower risk of hypertension and type 2 diabetes. Vegetarians tend to have a lower body mass index (BMI) and lower overall cancer rates. Vegetarian diets tend to be lower in saturated fat and cholesterol, and have higher levels of dietary fiber, magnesium and potassium, vitamins C and E, folate, carotenoids, flavonoids, and other phytochemicals. These nutritional differences may explain some of the health advantages of those following a varied, balanced vegetarian diet” (7).

Animal protein, on the other hand, has been associated with cardiovascular disease and cancer, even after confounders such as saturated fat have been taken into account (8,9).

A VEGETARIAN MENU

To illustrate the ease with which amino acid requirements are met on a meat-free diet, let’s look at a modest sample menu for a 170 lbs man in his 30’s.  The selection is modest on purpose, and not representative of the wide variety of plant based foods consumed by the average vegetarian or vegan.

Breakfast:

2 scrambled eggs (or, for vegans an equivalent amount of tofu scramble)
2 pieces of toast with margarine
1 glass of orange juice

Snack:

1 avocado

Lunch:

1 Frozen bean burrito, microwaved
1 Small salad (1 cup of shredded lettuce, 1 sliced tomato, with dressing)
6 oz. soy milk

Snack:

1/2 cup pistachio nuts

Dinner:

1 bowl vegetarian stew (peas, tomatoes, green beans, carrots, onions, parsnip, olive oil, seasonings)
1 cup mashed potatoes
1 tomato
2 slices of bread
1 small slice of cherry pie

Amino acid requirements for our subject:          Amino acid content of selected  menu:In this example, the vegetarian menu meets and surpasses the amino acid requirements of our hypothetical man.

Evidence that plant based diets can meet all of our essential amino acid needs abounds (1,3,4,5,6,7,9,10).  Yet, the myth persists.  Education, particularly in the medical community, is key to putting this silliness to rest.

REFERENCES

  1. Gropper SS, Smith JL, Groff JL. Advanced Human Nutrition, 5th Ed. 2009;179-182.
  2. World Health Organization. Nutrition Health Topics – Population nutrient intake goals for preventing diet-related chronic diseases. Available at: http://www.who.int/nutrition/topics/5_population_nutrient/en/index.html  Accessed February 21, 2012.
  3. Mangels R, Messina V, Messina M. The Dietitians’s Guide to Vegetarian Diets, 3rd Ed. 2011;65-83.
  4. Millward DJ.  The nutritional value of plant-based diets in relation to human amino acid and protein requirements. Proc Nutr Soc, 1999;58:249-260.
  5. Young VR, Pellett PL.  Plant proteins in relation to human protein and amino acid nutrition.  Am J Clin Nutr, 1994;59:1203S-12S.
  6. U.S. National Library of Medicine National Institutes of Health – Medline Plus Fact Sheets.  Protein in the diet. Available at:  http://www.nlm.nih.gov/medlineplus/ency/article/002467.htm  Accessed February 21, 2012.
  7. Position of the American Dietetics Association:  Vegetarian Diets. Journal of the ADA, 2009;109(7):1266-82.
  8. Preis SR, Stampfer MJ, Spiegelman D, Willett WC, Rimm EB.  Dietary protein and risk of ischemic heart disease in middle-aged men. Am J Clin Nutr, 2010;92:1265-72.
  9. Fontana L, Klein S, Holloszy JO. Long-term low-protein, low-calorie diet and endurance exercise modulate metabolic factors associated with cancer risk. Am J Clin Nutr, 2006;84:1456-62.
  10. Millward DJ, Fereday A, Gibson NR, Pacy PJ.  Human adult amino acid requirements: leucine balance evaluation of the efficiency of utilization and apparent requirements for wheat protein and lysine compared with those of milk protein in healthy adults. Am J Clin Nutr, 2000;72:112-21.