Do Vegetarians Live Longer?

What Are The Health Benefits Of A Vegetarian Diet?

Author: Dr. Stephen Chaney

“Vegetarians don’t live longer, it just seems that way.” Many of you have probably heard that joke, but is it true? Are vegetarians healthier? Do vegetarians live longer? Is meat going to kill you? Let’s take a deep dive into the pros and cons of vegetarianism.

What Is Vegetarianism?

Vegetarianism encompasses a wide range of diets. At one extreme is the vegan diet. Vegans eat only plant derived foods. They don’t eat fish, meat, milk, eggs, or honey. It also goes without saying they eat only whole foods (whole grains, plant proteins, and fruits & vegetables) and avoid things like sodas, sugary foods, junk foods, and convenience foods. The most extreme form of veganism, popularized by such recent movies as “Eating You Alive” and “What the Health,” also eliminates all oils. This keeps fat at <10% of total calories.

To avoid confusion, I will refer to this as a “very low fat vegan diet.” I will use the term “vegan diet” to refer to the more common veganism that includes vegetable oils in the diet. The vegan diet is still 100% plant based. It is also still relatively low in fat, generally in the 20-30% range. Since the fat comes from plants, it is predominantly the healthy monounsaturated and polyunsaturated fats.

Lacto-ovo vegetarians add low fat dairy foods and eggs to a plant based diet. The Ornish diet is a modified lacto-ovo vegetarian diet that also eliminates all oils and keeps fat at <10% of calories. Pesco-vegetarians add fish to a plant based diet, and semi-vegetarians add limited amounts of meat to a plant based diet.

Can Vegetarian Diets Reverse Atherosclerosis?

Let me start with studies on the very low fat vegan and Ornish diets. In addition to the diet, both programs emphasize regular exercise and stress reduction practices. Adherents to both plans generally achieve a serum total cholesterol of 150 or less. The Ornish diet and lifestyle program was designed to reduce the risk of cardiovascular disease, and it has been very well studied from that perspective. In studies of patients with severe atherosclerosis (clogged arteries) for periods of up to 5 years, the Ornish program results in a significant reduction in the degree of atherosclerosis (unclogs the arteries), inflammation, cardiac events (heart attack, stroke, etc.), and cardiac deaths (H.S. Dod et al, American Journal of Cardiology, 105: 362-367, 2010 ). Studies with the very low fat vegan diet are more limited, but suggest that it also reverses atherosclerosis and reduces cardiac deaths (C.B. Esselstyn et al, Journal of Family Practice, 63: 356-364, 2014 ).

Before moving on to other forms of vegetarianism, let me make the point that these are the only diets that have been shown to actually reverse atherosclerosis. That is a big deal.

The Seventh-Day Adventist Studies

Perhaps the largest group of studies on the health effects of vegetarians has been conducted on the Seventh-day Adventist population located in Southern California. Seventh-day Adventists believe that “God calls us to care for our bodies, treating them with the respect a divine creation deserves.” The Adventist church advocates a vegan diet consisting of legumes, whole grains, nuts, fruits, and vegetables. However, it allows personal choice, so a significant number of Adventists choose lacto-ovo vegetarian, pesco-vegetarian, or semi-vegetarian diets.

That diversity has not only allowed studies of the Adventist population to not only compare a vegetarian diet to the standard American diet of the non-Adventist population living in the same area, but also to compare the various forms of vegetarian diets. There are dozens of published studies and several reviews on this topic. I will cite only the most recent review here (L.T. Le and J. Sabate, Nutrients, 6: 2131-2147, 2014 ), but I will provide a complete list in my upcoming book.

This and other reviews have concluded that vegetarians weigh less, have less inflammation, have lower cholesterol levels and have lower risk of diabetes, heart disease, and hypertension than non-vegetarians. When we compare the various forms of vegetarianism, vegan diets appear to offer somewhat greater protection against obesity, hypertension, diabetes, and cardiovascular mortality than lacto-ovo and semi-vegetarian diets. The health benefits of vegetarian diets also seem to be somewhat greater for men than for women. One might speculate that might be because the average American male has a worse diet than the average American female. So, when men adopt a vegetarian diet, it may represent a greater improvement.

The reviews also looked at the nutritional adequacy of vegetarian diets. Vegetarian diets in general are very rich in antioxidants, most B vitamins, and polyphenols. Nutrients of concern for vegan diets are vitamin B12, vitamin D, calcium, iron, zinc, and long chain omega-3 fatty acids. Of those, vitamin B12 and long-chain omega-3 fatty acids are the ones most likely to require supplementation. Adequate levels of the other nutrients can be achieved by a well-designed vegan diet.

I would add protein to the list. Don’t misunderstand me. It is possible to get adequate protein on a vegetarian diet that includes beans and other legumes as a protein source. However, vegan advocates have been telling people they get all the protein they need from broccoli and other vegetables. That is incredibly bad advice, especially for seniors who are likely to suffer from sarcopenia (age related loss of muscle mass). Broccoli only provides 3 grams of protein per serving. You would need 15 servings to meet the protein RDA for women and almost 19 servings for men. Unfortunately, I often run across seniors who think they are getting all the protein they need from green salads and steamed vegetables. The bad advice from vegan advocates may be condemning them to unnecessary frailty in their old age.

What about the health claims of the low carbohydrate diets? Most of those “health benefits” are inferred from changes in blood parameters that occur over the first few weeks or months someone adopts those diets. There are no long-term data showing that low carbohydrate diets reduce the prevalence of diabetes, heart disease or cancer. Moreover, the few studies that compare low carbohydrate and vegetarian diets suggest the vegetarian diet is superior. For example, a recent study (M. Miller et al, Journal of the American Dietetic Association, 109: 713-717, 2009 ) compared the Atkins diet (the granddaddy of the low carb diets) with the Ornish diet. People on the low-fat Ornish diet had significantly lower LDL-cholesterol, apoB, and C-reactive protein (a marker of inflammation) and had better arterial function than people on the high fat Atkins diet.

What about the original question. Do vegetarians live longer? The answer isn’t clear. The Adventist Health Studies have reported that Adventist men live 6-7 years longer and Adventist women live ~4 years longer than their non-Adventist neighbors. However, the Adventist population may have other characteristics that contribute to their longevity. I will cover that in the section on “Blue Zones” in my upcoming book. In contrast, a very recent Australian study(S. Mihrshahi et al, Preventive Medicine, 97: 1-7, 2017 ) concluded that all-cause mortality was virtually identical for vegetarians and non-vegetarians. However, the authors of this study speculated that vegetarians in Australia have become less healthy in recent years because they are now consuming more high-sugar, processed “vegetarian” foods. Remember what I said about “Big Food Inc.” not being your friend.

What Does This Mean For You?

There are a few simple take-home messages from the research on the various forms of a vegetarian diet:

The Ornish diet and the very low fat vegan diet are the only diets shown to reverse atherosclerosis. If you have serious heart disease and would like to minimize your reliance on drugs and surgery, you should consider them. You will, of course, want to let your doctor know what you are doing.
Vegetarians are leaner and significantly healthier than non-vegetarians.
Vegans are slightly healthier than lacto-ovo and semi-vegetarians, but even vegetarians who include some dairy, eggs & meat in a primarily plant-based diet are much healthier than most Americans.
Vegetarians may not live longer, but they do live healthier longer.

There are also several subtle, but equally important, implications from these studies:

You can forget the claims you must be a vegan purist to obtain any health benefits from vegetarianism.If you watch movies like “Eating You Alive” or “What the Health”, you are led to believe you will suffer terrible health consequences if you add any dairy, eggs, or meat to a vegan diet. In fact, the evidence for reversing atherosclerosis is stronger for the Ornish diet, which is a lacto-ovo-vegetarian diet, than it is for a pure vegan diet. For several other health outcomes, the vegan diet is slightly more effective, but both lacto-ovo-vegetarian and semi-vegetarian diets are much healthier than the standard American diet.
Vegetarian diets are whole food diets.If you start adding in processed and convenience foods, even if they are labeled “vegan,” you are likely to lose all the health benefits of a vegetarian diet.
You can forget claims that you get all the protein you need from vegetables like broccoli. That is incredibly bad advice which is likely to condemn seniors to unnecessary frailty in old age.
You can forget the claims that you must avoid carbs at all costs. The proponents of the low carb diets will tell you that recommendations to limit fat are based on a lie. They tell you that fat is good for you and carbs will cause you to gain weight, increase inflammation, and increase your risk of diabetes, heart disease, and cancer. You are told to avoid grains and any other foods containing carbohydrate, including some fruits and vegetables. The “danger” of carbohydrates is only true for the refined grains, sugary sodas and junk foods in the standard American diet. Vegetarian diets emphasize whole grains, fruits and vegetables. They are high in carbohydrate and low in fat, and they reduce weight, inflammation, diabetes, heart disease, and some cancers.
You can forget most claims of weight loss. Most low carb diets tout rapid initial weight loss. Unfortunately, most of that weight comes back a year or two later. Only vegetarian diets are associated with lower weight over a period of many years.

In summary, a pure vegan diet is probably the healthiest form of vegetarianism, but it is difficult to follow. Vegetarian diets that are primarily plant based, but contain small amounts of dairy, eggs, or meat are also very healthy, and may be easier for the average American to follow.

The Bottom Line

Vegetarianism encompasses a wide range of diets. The standard vegan diet is entirely plant-based. There is a very low fat version of the vegan diet that also eliminates all oils. Lacto-ovo-vegetarian diets include some dairy and eggs. Semi-vegetarian diets include some meat. The Ornish diet is a very low fat version of the lacto-ovo-vegetarian diet.

There are a few simple take-home messages from the research on the various forms of a vegetarian diet:

The Ornish diet and the very low fat vegan diet are the only diets shown to reverse atherosclerosis.
Vegetarians are leaner and significantly healthier than non-vegetarians.
Vegans are slightly healthier than lacto-ovo– and semi-vegetarians, but even vegetarians who include some dairy, eggs & meat in a primarily plant-based diet are much healthier than most Americans.
In a head to head comparison, the Ornish diet was significantly healthier than the Atkins diet.
Vegetarians may not live longer, but they do live healthier longer.

There are also several subtle, but equally important, implications from these studies:

You can forget the claims you must be a vegan purist to obtain any health benefits from vegetarianism. Primarily plant-based diets with small amounts of dairy, eggs or meat are also very healthy.
Vegetarian diets are whole food diets. If you start adding in processed and convenience foods, even if they are labeled “vegan,” you are likely to lose all the health benefits of a vegetarian diet.
You can forget claims that you get all the protein you need from vegetables like broccoli. That is incredibly bad advice which is likely to condemn seniors to unnecessary frailty in old age.
You can forget the claims that you must avoid carbs at all costs. That is only true for the refined grains, sugary sodas and junk foods in the standard American diet. Vegetarian diets are high in carbohydrate, low in fat, and very healthy.
You can forget most claims of weight loss. Only vegetarian diets are associated with lower weight over a period of many years.

For more details, read the article above.

These statements have not been evaluated by the Food and Drug Administration. This information is not intended to diagnose, treat, cure or prevent any disease.