FAQ: Health professionals

A. Vegans who eat a well-structured plant-based diet based on whole foods do not have any problem getting enough vitamins, minerals, and in fact, all nutrients needed for health.  In fact, in the U.S., our health issues are not a result of nutritional deficiencies, but rather nutritional excesses; we eat too much fat, too much protein, too many calories.  Doctors rarely see deficiency conditions in our well-fed (one could argue over-fed) population.

Calcium needs are easily met on a well-structured, plant-based diet too.  Calcium needs are actually quite low – only 400-500 mg per day.  An orange has about 100 mg of calcium and a sweet potato has 90 mg.

Vitamin D, in my opinion, should be re-classified as a hormone rather than a vitamin because, unlike vitamins, the body produces vitamin D in response to sunlight exposure.   An excerpt from my latest book, Solving America’s Healthcare Crisis, on vitamin D discusses the common misunderstandings about healthy vitamin D levels, the relationship of vitamin D to disease conditions, and the advisability of supplementation.

Many health care practitioners continue to insist that lower vitamin D levels are related to the development of conditions ranging from depression to cancer.  It is true that people with many diseases do seem to have lower blood levels of vitamin D.  Are these lower levels the cause of these conditions?

This does not seem to be the case.  Animal protein consumption results in an increase in the production of insulin-like growth factor (IGF-1), which can cause abnormal cell proliferation, or cancer. As mentioned earlier, the consumption of animal protein also interferes with the body’s ability to convert the storage form of vitamin D to its active form.   It may be that lower vitamin D levels are not the cause of cancer, but simply markers for dietary patterns that increase the risk of cancer significantly.  In other words, low vitamin D levels may be correlated to cancer incidence, but not be the cause of cancer.

The aforementioned Institute of Medicine’s committee agreed, stating that claims that lower vitamin D levels cause disease   “are not supported by the available evidence.”  The committee found that these claims were based on observations and that there has been no credible research establishing a cause and effect relationship.

Other studies do not support a link either. Researchers at the National Cancer Institute measured the vitamin D levels of 17,000 people.  Ten years after the study began, 536 people had died of cancer.  There was no correlation between vitamin D levels and the risk of dying of cancer.[i]

Another study, the RECORD trial, involved 5,292 patients who were enrolled through 21 health centers in England and Scotland.  The participants were randomized to receive 800 IU of vitamin D, 1000 mg calcium, both, or placebo; and then followed for 24-62 months.  The study was conducted to assess the relationship between vitamin D deficiency and insulin production, and to determine if insulin production could be increased with vitamin D supplementation.

The researchers found no evidence that supplementation with vitamin D, either alone or with calcium, prevented the development of diabetes or reduced medication levels for diabetics.[ii]

Michael Hollick, M.D., Ph.D., is a highly respected researcher and an expert on vitamin D.  He is a professor of medicine and physiology, and formerly of dermatology, at Boston University School of Medicine, and (until 2000) chief of endocrinology, metabolism and nutrition.

According to Dr. Hollick, oral supplementation is an inefficient way to increase vitamin D levels.  Dr. Hollick instead recommends sun exposure.  He says that just 10-15 minutes in the sun is the equivalent of taking between 15,000 and 20,000 IU’s of vitamin D, but without the potential for toxicity that is becoming more common as people take larger doses of it orally.[iii]

There is a difference between vitamin D synthesized from the sun and vitamin D taken orally, since there are additional photoproducts made in response to sun exposure that are not in the supplement form of vitamin D.  That means that it is important to enable the body to make vitamin D rather than to supplement with it.

As is the case with so many isolated nutrients, there are risks associated with taking vitamin D supplements.  For example, men may increase their risk of prostate cancer by taking vitamin D supplements.[iv]

And vitamin D supplements given to women were shown to increase their “bad” LDL cholesterol by 4.1% and reduce their HDL/LDL ratio by 10.5%.[v]  Supplements and fortified milk have caused toxic effects in some people.[vi]

And the Institute of Medicine report concurred, stating that supplementation leading to higher levels of vitamin D can increase the risk of fracture, disease, and all-cause mortality.  The committee also wrote that while studies were not conclusive, that vitamin D supplements were not a good idea in the absence of proven benefit.  The committee found evidence “challenging the concept that ‘more is better.’

In conclusion, the current body of research does not support the idea that most people are deficient in vitamin D; that lower vitamin D levels are the cause of disease; or that supplementation is safe or effective. 

Sunlight exposure and dietary excellence™ are the best ways to insure adequate blood levels of vitamin D.

Aside from obesity related diseases like T2 diabetes and heart disease are there any other conditions helped by a plant-based diet? 

All conditions can be made better with a well-structured plant-based diet.  The extent to which they can be made better varies depending on how long the person has suffered with a disease and medications that have been taken.  The reason we can make this statement with a great deal of assurance is that the leading cause of degenerative diseases is poor dietary choices.  When the food improves, the condition improves too.

Diabetics are often told to eat a diet high in animal protein in order to control blood sugar levels.  While this strategy works in the short-term, it leads to long-term health issues such as coronary artery disease and kidney failure.  Additionally, even the leanest animal foods have a high fat content, and fat intake is counter-productive for improving the health of diabetics. Diabetics are prone to store more fat in their cells, and increased fat storage leads to increased insulin resistance.  A better option is to adopt a plant-based diet for arresting or reversing type 2 diabetes.

Dr. James Anderson at the University of Kentucky has used dietary intervention on both type 1 and type 2 diabetics.  In one study, he placed 25 type 1 and 25 type 2 diabetics on a whole-foods, plant-based diet high in both carbohydrate and fiber.  After just three weeks, the type 1 diabetics were able to lower their insulin requirements by 40% and their cholesterol dropped by 30%.   Twenty-four out of twenty-five type 2 diabetics were able to completely discontinue their insulin medication in only a few weeks.[vii]

Dr. Neal Barnard, President of the Physicians’ Committee for Responsible Medicine, has also been conducting research using diet to reverse or stop the progression of type 2 diabetes for many years.  He has presented his findings at Continuing Medical Education (CME) conferences, published numerous articles in medical journals, and developed an entire division within PCRM to educate diabetics and their families about diet and diabetes.

Dr. Barnard’s studies have compared diabetics following a low-fat vegan diet that does not limit the consumption of calories, carbohydrate, or portion sizes, with patients following a diet based on the American Diabetes Association’s guidelines.  His research consistently shows that patients lose more weight, are able to significantly reduce or even eliminate medications, and show significant improvements in A1C levels (a marker for average blood sugar levels during the previous 2-3 months) after only a few weeks.  Additionally, patients following the vegan diet experience rapid drops in blood cholesterol levels, which is significant since most diabetics die from cardiovascular disease.

(references)

[viii]  [ix][i] Freedman, D.Michal, et al, “Prospective Study of Serum Vitamin D and Cancer Mortality in the U.S.,” J Natl Canc Inst Oct 30 2007; 99(21):1594-1602; doi 10:1093[ii] Avenell, A, Cook J, MacLennan G, McPherson G.  “Vitamin D Supplementation and Type 2 Diabetes: A Substudy of a Randomised Placebo-controlled Trial in Older People.” Ageing. 2009;38(5):606-609.[iii] Alternative Therapies May/June 2008 vol 14 no [iv] Tuohimaa P, Tenkanen L, Ahonen M, Lumme S,  et al. “Both high and low levels of blood vitamin D are associated with a higher prostate cancer risk: a longitudinal, nested case-control study in the Nordic countries.”  Int J Cancer. 2004 Jan 1;108(1):104-8.[v] Heikkinen AM, Tuppurainen MT, Komulainen M, et al.   “Long-term vitamin D3 supplementation may have adverse effects on serum lipids during postmenopausal hormone replacement therapy.”  Eur J Endocrinol 1997;137:495-502.[vi] Jacobus CH, Holick MF, Shao Q, Chen TC, Holm IA, Kolodny JM, Fuleihan GE, Seely EW.  “Hypervitaminosis D associated with drinking milk.” N Engl J Med. 1992 Apr 30;326(18):1173-7[vii] Anderson JW. “Dietary fiber in nutrition management of diabetes.”  In: G. Vahouny, V and D Kritchevsky (eds), Dietary Fiber: Basic and Clinical Aspects.” Pp.343-360. New York: Plenum Press,1986.[viii] Neal Barnard, M.D. et al, “A Low-Fat Vegan Diet Improves Glycemic Control and Cardiovascular Risk Factors in a Randomized Clinical Trial in Individuals With Type-2 Diabetes.”  Diabetes Care 29:1777-1783 1006 DOI: 10.2357/dc06-0606[ix] Neal Barnard, M.D. et al, “Changes in Nutrient Intake and Dietary Quality Among Participants With Type 2 Diabetes Following a Low-Fat Vegan Diet or a Conventional Diet for 22 Weeks.” J Am Dietetic Assoc. October 2008 vol 108  #10;1636-1645