I have talked and written about the China Study extensively, but that study alone does not tell the complete story of the health impacts of vegan and vegetarian diets. With the Vegan Health Study, however, we have quite a bit of information on the subject to contend with.
In my view, the PETA point of view is clearly biased (and it pains me to see celebrities advertise their slogans). Unfortunately, PETA is the main source of information for a lot of vegans and vegetarians. They have converted millions and done a lot to define debates about health in their terms. The other day in my school’s staff lounge at lunch, when eating burritos wrapped in collard greens instead of tortillas, I was asked, “Are you a vegetarian? That looks like something a vegetarian would eat.” I digress.
The benefits
The advantages of the vegan diet are clear. If processed carbs (sugar, white flour, etc.) are avoided and vegetables are consumed organic, cardiovascular disease, type 2 diabetes, certain types of cancer, genito-urinary disorders, high toxicity, certain auto immune disease, certain inflammatory disorders, gastrointestinal diseases, macular degeneration, and cataracts can all be prevented or improved1.
This makes sense. The vegan diet has the potential to be extremely catabolic and alkalizing, which is in stark contrast to the highly anabolic and acidifying Western diet, high in sugar and meat and low in raw vegetables. Anabolic diets are building diets; catabolic diets are restorative. Anabolic diets work great for many high performance athletes or people with fast metabolisms—something most of us clearly are not. For someone who has been doing poorly on an acidic diet for decades, an alkalizing diet is going to be soothing and restorative.
Extending this idea, the specific diseases that the Vegan Health Study shows to be helped by a vegan diet are the very diseases that will be caused in some people by the anabolic, acidifying Western diet. I am not surprised at all that veganism works in these situations, and the weight of these benefits should not be underestimated.
The disadvantages
The study shows that vegans face an entirely different set of problems.
B12 deficiencies are virtually guaranteed if quality supplements are not taken1. B12 deficiency can lead to artery damage, neurological disorders, birth defects with B12 deficient pregnant mothers, failure to thrive among breast feeding children of B12 deficient mothers, impaired intellectual development among B12 deficient children, and the development of macrocytic anemia, a blood system disorder1. The study recommends at least 2000 mcg of methylcobalamin B12 per week; I think taking 1000 mcg of methylcobalamin B12 daily in concert with a whole foods multivitamin with minerals would be adviseable1. The cheaper and more widely available cyanocobalamin form of B12 is poorly utilized by the body.
If vegans do not get high amounts of sunshine, vitamin D deficiencies become likely. Although vitamin D2 can be found in fortified foods and multivitamin, it is completely different molecularly from vitamin D3, the form found in animal foods and in our own bodies1,2. I never recommend vitamin D2.
There are also mineral problems. Vegan diets are often high in fiber, which can inhibit mineral absorption1. Plant foods are often low in iodine, magnesium, and zinc1. Calcium cannot be utilized without adequate vitamin D levels, so calcium deficiencies are common1. Iron is often poorly absorbed1. Deficiencies in calcium, magnesium, zinc, boron, manganese, vitamin D, or vitamin K can lead to osteoporosis1.
Vegan diets also lead to essential fatty acid deficiencies, particularly in the omega 3 fatty acids EPA and DHA1. This can lead to depression, weight gain, dry skin, low energy, compromised brain function in children, cardiovascular disease, cancer, diabetes, osteoporosis, schizophrenia, immune and inflammatory disorders including asthma, and lupus1. ALA (the form of omega 3 fatty acids found in plant foods) can be converted into to EPA and DHA (found only in animal foods), but at low conversion rates2. Some people are basically unable to convert ALA into EPA or DHA2. This problem is increased when high amounts of omega 6 fatty acids are consumed in concert with the omega 3’s (the ratio between the two is more important than the quantity of either one)1.
Most vegans get enough protein, but most also don’t get enough of particular amino acids1. Some of these amino acids are not made by the body (and are thus called essential), while others can be synthesized in the body. Without adequate amino acid intake, the body is constantly stressed to come up with the amino acids. For example, cysteine and methionine deficiencies—common among vegans—lead to poor carnitine production; carnitine is necessary for metabolizing fats for energy1.
Vegans who consume refined carbohydrates, trans fats, or insufficient fiber generally have elevated triglycerides and cholesterol and high blood pressure1. Refined sugar consumption is also correlated with aging in vegans1.
Recommendations
Vegans must eat primarily whole plant foods, minimize refined carbohydrates, consume healthy fatty acids (such as algae-derived DHA and hemp or flax seed), consume adequate trace minerals, take a methylcobalamin B12 supplement, limit refined salt intake, take a quality whole foods multivitamin, and get sunshine for vitamin D (remember that vitamin D2 is probably not going to cut it)1.
The adequate time of sunshine needed changes from person to person. People with a light complexion might only need five minutes per day to make enough vitamin D; people with a dark complexion may need an hour or more. Spending as much time as possible in the sun without sunscreen before getting burnt is advisable. Clearly, burning needs to be avoided at all costs, but unfortunately, many sunscreens block the forms of UV rays that are most beneficial. Also, according to Dr. Mercola, vitamin D absorption is a 24 hour process than can be inhibited if one showers with soap right after spending time in the sun.
Adequate protein consumption is vital. Vegetarian sources of proteins are all deficient in one amino acid or another; the trick is to consume proteins at each meal that compliment each other and leave no amino acid out3. Corn and beans together create a complete protein. More examples can be found in Diet for a Small Planet by Frances Moore Lappe. Supplementation with a protein powder containing all of the amino acids would be advisable.
One final caveat that must be discussed is that of metabolism. The science is clear: some people oxidize their foods more quickly or slowly than others. This means that some people (fast oxidizers) need more protein and fats in order to have sustained and stable energy after meals, while other people (slow oxidizers) need more carbohydrates to achieve the very same goal. The vegan diet is in almost every instance going to be a high carbohydrate diet, and this is going to cause fast oxidizers to be hungry, feel irritable, gain weight, etc. When making significant dietary changes, care should be taken to ensure that the new diet improves energy levels, mood stability, bowel health, and well being.
1. Vegan Health Study (http://www.vnv.org.au/site/index.php?option=com_content&task=view&id=193&Itemid=67)
2. Fallon, Sally. (2001). Nourishing Traditions. Washington, DC: NewTrends Publishing, Inc.
3. Lappe, Frances Moore. (1991). Diet for a Small Planet. New York: Ballantine Books.
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