Eat Yourself Fitter: is a vegetarian diet healthier than eating meat?

People adopt a vegetarian diet for a variety of reasons - concern for the environment, economic and world hunger concerns, compassion for animals, belief in nonviolence, food preferences, health, religious beliefs. I want to consider the health consequences of vegetarian diets: are vegetarians deficient in certain nutrients or do they, in fact, live longer than their meat-eating fellow humans?  Perhaps a more important question is this: can we humans get all the nutrition we need for non-animal sources?  Is the slaughter of animals a necessity or a choice?

 Human beings have been eating meat throughout recorded history and beyond. Indeed, meat is identified alongside fish, eggs and beans as an important source of protein in a healthy diet as recommended by those charged with protecting the nation’s health. It is a rich source of nutrients central to human health which are less readily found in a meat-free diet, including zinc, calcium, iron, ω-3 fatty acids, and vitamins D and B12.

Vitamin B12 is of particular significance as the only food sources for it are animal-based.  Deficiency in vitamin B12 is linked to anaemia, nerve damage, heart disease and pregnancy complications. 

For a strict vegetarian or vegan, vitamin B12 needs to be added to their diet through fortified foods and supplements, just as is recommended for everyone over the age of fifty regardless of whether they eat meat. However, one study found that 92% of vegans and 47% of lacto-ovo vegetarians were deficient in this critical nutrient. One study even found an association between vegetarian diet and three chronic diseases: allergies, cancers and mental illness.

Having considered these drawbacks to a meat-free diet, perhaps it is surprising to read that vegetarians live longer. Several years longer, according to one well-publicised study which found vegetarians within its sample had a 12% lower risk of dying over the study than meat-eaters. Although pesco-vegetarians came out on top in the life length stakes, the study found that a range of vegetarian diets, from vegan to those who eat eggs and dairy products, appear to be healthier than those “dominated by processed foods and meats”.

These results, although startlingly, reflect many others which have found that vegetarians tend to have lower total and LDL cholesterol, lower blood pressure and lower body mass index (BMI), all of which are associated with longevity and a reduced risk for many chronic illnesses. Vegan and vegetarian diets also protect against obesity and the risk of type 2 diabetes.

However, this does not necessarily mean that a vegetarian diet in itself causes the attendant health benefits.  Studies showing these benefits for vegetarians are frequently accused of healthy user bias – this argument basically suggests that, 

“People who engage in one behavior that is perceived as healthy are more likely to engage in other behaviors that are healthy”.  

The implication is that vegetarians are more likely to exercise regularly and to eat fruit and vegetables, while at the same time less likely to engage in unhealthy activities such as smoking, excessive drinking, etc., than the populations to which they are being compared.  They are also likely to remove refined sugar, refined grains, trans fats and many processed foods for their diet.  Although the vegetarians have better health, like the study showing an association with allergies, mental illness and cancers, the available data cannot prove that omitting meat from their diet caused these differences.

  

The healthy user bias criticism seems to be gain credibility from a study of vegetarians and non-vegetarians who were health store customers (and therefore assumed to be equally likely to exhibit behaviours conducive to good health) which failed to find a significant difference in the longevity of these two groups, or the instance of heart disease or stroke. However, the scientists who conducted the study acknowledged that “The validation study suggested that subjects' diets did change during the first few years of follow up in respect to vegetarian diet” and that “Changes in dietary habits would be expected to result in underestimation of any associations found.”  This could be why the study initially found a significant link between health benefits and a vegetarian diet, but on follow up ten years later, this link had fallen to a level deemed statistically insignificant.

What can we conclude from this often contradictory information?  Is a vegetarian diet healthier than those including meat, or do those stereotypes of pale, nutrient-deficient lettuce-munchers hold water?  There are people ready to champion the cause of superior vegetarian health, while others are equally passionate in arguing the benefits of eating meat. The nutritional advantages of meat are easily compensated for in a healthy vegetarian or even vegan diet, and that word “healthy” is key:  all the health benefits associated with a vegetarian diet – longer life, lower risk of heart disease, obesity and type 2 diabetes, etc – are dependent on a varied and well-balanced range of food and nutrients being consumed.  It is possible to eat a vegetarian diet as unhealthy as any meat-dominated one, just as it is possible to eat very healthily and still include meat.  Indeed, for optimal health, many nutritionists seem to favour a well-balanced diet including some fish, poultry and even a small amount of unprocessed red meat, if only because such a diet requires less attention to nutrition than vegetarianism and is therefore easier to manage.  A good example of this is the ‘Mediterranean diet’, rich in legumes, nuts, fruits, vegetables and whole grains, as well as olive oil, seafood and moderate wine consumption, but very little red meat.

So, a vegetarian diet is one of the healthiest, but seems to share much of its benefits with other healthy, balanced eating plans which require less effort. If you are looking only to improve your health, perhaps a diet including some unprocessed meat and fish might be an easier choice, especially if you really can’t live without the occasional juicy steak or the thought of never again eating fresh-grilled sardines is just insufferable.  However, if you have other reasons for deciding to cut animal-based food out of your diet, you can be confident that your health would not be adversely affected by even a well-planned vegan diet.  To quote Adam Blais of the ‘Debunking Nutrition’ website,

“If we lived in a world where supplements were not available and we had to rely on our present food supply, then advising vegans to consume animal products might make more sense from a nutritional standpoint. However, based on the current reality and the scientific literature, a well-educated vegan can follow a whole foods plant-based diet without fear of any nutrient deficiencies.”

The idea of needing to take nutritional supplements alongside one’s food may not sound appealing, but it is the reality of life for many people over the age of fifty, regardless of their preferred diet.  As to the question regarding whether there is a nutritional necessity for humans to eat meat and other foods derived from animals, perhaps it would be helpful if a large association of health professionals and nutritionists reviewed all the data available and came to an official position on the matter. Luckily for us, the Dieticians of Canada and the Academy of Nutrition and Dietetics (formerly known as the American Dietetic Association) have done exactly that:

“Well-planned vegan and other types of vegetarian diets are appropriate for all stages of the life cycle, including during pregnancy, lactation, infancy, childhood, and adolescence.”