Are vegetarian diets healthy?

Food has been one of the past decade’s biggest celebrities.

It’s not just star chefs, food so artfully presented it could hang in a gallery and the enchanting Food Network that have been grabbing our attention--there’s also a rising and keen interest in the impact food choices have on our health and the health of our environment. What and how we eat has evolved from a simple nourishment act to a lifestyle, ethical and self defining evaluation--and with choices come questions.

As a lifetime vegetarian, I get many comments and questions about vegetarianism and health and my personal choice, so I'd like to get back to a post I wrote earlier and discuss the current understanding of the health impact of vegetarian diets and where I stand.

Let’s start with a few common definitions--these definitions of course fall short of describing the full range of dietary practices of those who restrict animal products from their plate, and there are many variations not covered by these rather simplistic definitions.

Vegetarians exclude meat and fish from their diet but do eat dairy and eggs. Vegans exclude all animal products, including meat, fish, dairy and eggs. The terms “vegetarian” and “vegan” are not interchangeable from the nutritional science point of view; the two diets are quite dissimilar. This discussion is about vegetarians and not vegans.

Vegetarians choose to abstain from meat for a variety of reasons, ranging from health advantages and environmental priorities, to ethical and cultural considerations. This post is mainly about the health aspects of going vegetarian.

Are vegetarian diets nutritionally complete?

Simply stated--yes!

It’s now proven that a healthy, varied vegetarian diet is nutritionally adequate, doesn’t lead to any deficiencies of macro or micro nutrients and needs no supplementation.

Contrary to popular myth protein isn’t a problem for vegetarians.
Plants--especially pulses (peas, beans and lentils), nuts, seeds and grains--have plenty of protein. Plant proteins do not have all essential amino acids in every bite and are therefore considered incomplete proteins. However, we now know that incomplete proteins can be stored in the body for many days to be combined with other incomplete proteins. Since different plant foods together contain all essential amino acids, it doesn’t matter if the proteins are complete or incomplete and it’s also no longer recommended to bother with combining those different proteins in the same meal.

Contrary to common belief, the risk of iron-deficiency anemia is no larger for vegetarians than it is for omnivores.

Are vegetarians healthier?

A recent paper by Gary E. Fraser in the American Journal of Clinical Nutrition provides a balanced summery of the current science.

As you can imagine, studying large vegetarian cohorts is no easy task. There are a few such large cohorts. The California Adventists have been studied since 1958 and the study’s ongoing. The Seventh-day Adventist church is a Christian denomination that observes Saturday as the day of worship, but it’s also known for promoting a “healthy message,” including a vegetarian diet and avoidance of alcohol, caffeinated drinks, tobacco (they’ve been denouncing smoking for 150 years, well ahead of the medical community) and illegal drugs. Not all Adventists are vegetarian, so the effect of vegetarianism can be isolated within the Adventists. Other large study cohorts include the Health Food Shoppers’ Study and the Oxford Vegetarian Study both from the UK, and the German Heidelberg Vegetarian Study.

Fraser finds consistency in outcomes of vegetarian lifestyles across studies for the following considerations:

• Coronary heart disease is clearly lower for vegetarians. A combined analysis of these cohorts shows that non-vegetarians have 32% higher heart disease mortality than do vegetarians.

• Total LDL cholesterol is lower in vegetarians.

• Vegetarians are thinner than non-vegetarians.

• The risk of diabetes and hypertension is probably lower for vegetarians across studies.

Where Fraser finds inconsistent results is in the incidence of colon cancer. There’s general agreement from studies of non-vegetarians that red meat consumption increases the risk of colon cancer. The Adventists studies show that vegetarian Adventists indeed have a lower incidence of colon cancer, but the EPIC-Oxford study doesn’t show that vegetarians fare any better than the general British population. This of course demands explanation and further study.

Is the evidence suggesting health benefits from a vegetarian diet compelling enough to convince a meat lover to quit all meat? I doubt it.

One might argue--and I'll concur--that although there are studies that show a correlation between vegetarian lifestyles and lower incidence of several chronic diseases, the evidence is far from conclusive, and there are many confounders in the study of a self-selected group such as vegetarians. And although the evidence to support a diet rich in fruits and veggies and whole grains is convincing, there isn’t great proof that consuming quality meat in moderation is harmful.

I believe that most traditional diets, based on mostly plant food have proven themselves over time to be healthful. Indeed, people can thrive on many different diet regimens. The one diet that’s proving to be detrimental to health is our current Western diet of highly processed foods, fast foods and junk.

One hallmark of the American diet is very high consumption of animal products and especially meat (about half a pound of meat a day). What’s even worse is that most of those animal products come from animals raised in feedlots on a diet that’s unnatural to them (grains and even animal by-products, instead of grass, in the case of cows) and regimens of antibiotics and hormones.

So what’s my story?

My dad turned vegetarian when, as a kid, he saw a chicken slaughtered. When I was a teeny toddler my dad told me where meat comes from. He also told me that almost everyone eats meat, but he thinks animals do have a desire to live, show attachment to their young and do experience suffering.

I was convinced and never tasted meat. I am concerned about animal welfare, and I think cruelty to animals—expressed in the extreme in feedlots and industrial slaughterhouses—has reached a point in which most people would be appalled if they actually saw where their meat comes from.

I admit it…for me it’s easy. I have no desire to eat meat and don’t even think of it as food, because I don't have a habit of eating it.

This is my anecdotal proof that what you feed your kids when they're young has a profound impact on their eating habits. I haven’t gone any further than my dad did with animal welfare--I live with no small amount of hypocrisy myself. I do eat cheese and eggs. I’ll try to buy from producers that raise their animals in a humane and sustainable way, but I do realize that it's very difficult to give up foods you enjoy, were raised on and are part of your tradition. I don’t think I’d likely give up dairy completely, even if there were evidence that abstaining from it might benefit my health somewhat. After all, there’s risk everywhere; avoiding risk to the point of not enjoying yourself is risky too.

Every diet is characterized by which foods are eaten, not only by what’s excluded. At this point I think there’re plenty of reasons for everyone to eat more fruits and veggies and eat less animal products; it may turn out that the health benefits seen in vegetarians have more to do with what they eat, and not what they exclude.

There’s much more to talk about concerning vegetarian lifestyles, and I haven’t even touched on the environmental reasons to avoid meat, which are pretty compelling.

I welcome your perspectives.

Dr. Ayala
Related post: Eating green for our planet

Posted as part of Breastfeeding Moms Unite's Vegetarian Foodie Friday.