Questions Raised About Vegetarian Diets

I have previously highlighted the nutritional attributes of meat (and there are many). I appreciate that not everyone wants to eat meat. Some don’t like to eat it, and some will not eat it on moral, ethical, animal-welfare, or religious grounds.

I have no objection to any of this. I just think for those of us who do eat meat, it’s not a bad thing to know just how nutritious and potentially health-giving this food can be, despite conventional wisdom on nutrition.

I also believe that it’s not a bad thing for vegetarians to be aware that the omission of meat and fish from the diet can put them at risk of certain nutritional deficiencies.

These were highlighted in an article published in December in the journal Nutrition in Clinical Practice. This article specifically highlights the fact that vegetarian diets tend to be low in vitamin B12, vitamin D, omega-3 fatty acids, calcium, iron, and zinc. It also recommends the use of supplements and fortified foods to provide “a useful shield against deficiency.”

This article goes on to claim, however, that vegetarians have reduced rates of death from ischemic heart disease and decreased incidence of hypertension, stroke, Type 2 diabetes, and certain cancers than do nonvegetarians. I hear these claims for vegetarian eating a lot, but do they stand up to scrutiny?

The idea that vegetarians enjoy a health advantage over omnivorous eaters is based on the findings of epidemiological studies. These studies may show an association between vegetarianism and improved health, but that does not mean the vegetarianism is causing the improved health.

It is possible that any apparent benefits to health that appear to come from vegetarianism may come not from the absence of meat and fish from the diet, but from other factors associated with vegetarian living, such as a reduced tendency to smoke and healthier exercise habits.

These so-called confounding factors need to be taken into consideration in order to make a fair assessment of the relative merits of vegetarian and nonvegetarian diets. Some researchers have attempted to make a more accurate assessment of the benefits (or otherwise) of vegetarian eating by taking into account these confounding factors.

In one study published in September 1996 in the British Medical Journal, researchers attempted to counteract any confounding factors by focusing only on individuals who shopped in health food stores. The idea is that all of these individuals are generally health-conscious, whether they are vegetarian or not. This allows a fairer appraisal of the impact of vegetarian or nonvegetarian eating.

This study found that compared to the general population, death rates in vegetarians and nonvegetarians were significantly lower than in the general population, which supports the notion that health-food shoppers are a generally health-conscious bunch. However, overall risk of death in vegetarians and nonvegetarians was the same.

In another study, published in June 1993 in the British Medical Journal, vegetarians were asked to recruit their friends and family into the study. Doing this was thought to help ensure that all individuals in the study were similarly health-conscious.

Again, this study found that vegetarians and nonvegetarians had risk of deaths lower than that of the general population. However, again, death rates for vegetarians and nonvegetarians were essentially the same.

Another bit of research, published in Public Health Nutrition in January 2007, compared vegetarians and nonvegetarians and undertook a quite detailed analysis of the dietary habits of some 56,000 individuals. This study yet again found that the overall risk of death in vegetarians was not lower than in nonvegetarians.

And what about the claim that vegetarian diets are better for the heart? None of these studies found any evidence for this contention either.

So the plain facts show that, overall, there is no broad health advantage to be had from eating a vegetarian diet. In other words, while individuals may not be keen to eat flesh foods on moral, ethical, or religious grounds, there does not appear to be a good argument for vegetarianism on grounds of health.


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