Less meat, More life

Vegetarians outlive non-vegetarians by several years.  The result may be largely (or entirely) due to lower weight, and higher consumption of fresh vegetables and fruits, rather than to an adverse effect of meat per se.   Vegans have an even greater advantage than vegetarians who eat dairy and eggs, and again vegan weight trends even lower than other vegetarians.  It goes without saying that in this context a longer life goes hand-in-hand with a healthier life. Rates of diabetes, heart disease, and selected cancers are much lower in vegetarians, and yet lower in vegans.  

 

I have been a vegetarian since 1973, motivated (now) by years of habit and (then) by a hypnotic suggestion from my first yoga teacher.  One evening, about five months into my discovery of yoga, I was lying on the floor in savasana (deep relaxation) when the revered and beloved voice of my teacher suggested to the class that perhaps we might find our practice leading us to eat less meat.  I was startled awake, and sat bolt upright.  In previous weeks, she had suggested cutting back coffee and alcohol and TV and marijuana (this was Berkeley!) and cigarettes—it all went down smoothly because I had never been attracted to any of those things.  But what could she be thinking, classing meat with intoxicants and mind-altering drugs?  I had never questioned that a diet that was ultra-high in protein would keep me strong and healthy.  The phrase “new age hocum” hadn’t been invented yet, but those are just the words for which my mind was searching.

Six weeks later, I was a vegetarian.  My teacher’s hypnotic suggestion awakened my discomfort with surrogate killing of animals.  It had nothing to do with science.  Now there is evidence linking low meat consumption with longevity, but much less was known 40 years ago, and even that was unknown to me.  I became aware that I was uncomfortable eating animals, and I have never looked back.

Years later, I raised my two daughters to eat whatever they wanted to eat, and was secretly delighted when, as pre-teens, they each decided that (though they enjoyed the taste of meat), it was too unsettling for them to think of the animal who died to become their meal.  Both daughters have maintained their vegetarianism into adulthood, though everything else about them has changed.

As a public health advocate, I have been very cautious about suggesting vegetarianism to anyone.  I am still wary that my own habits and emotions may be affecting my judgment.  But more studies than ever support the role of vegetarianism in a life extension plan, and prompted by a recent ScienceDaily article, I’ll look at vegetarian diets in this week’s column.

 

Seventh Day Adventist Study

Studying the long-term consequences of a vegetarian diet is complicated by the fact that vegetarians are far from a random sample.  There are a lot more women than men, more liberals than conservatives, more environmental awareness, more health-consciousness, more propensity to exercise among vegetarians [2012 Gallup poll].  More surprisingly, vegetarianism is associated with fewer years of education, and there are a lot more Baby Boomer vegetarians than among younger generations.

41% of Seventh Day Adventists call themselves vegetarians, compared to 5% of Americans generally.  This makes SDA an ideal population to a study the effects of a vegetarian diet holding other factors fairly constant.  Vegetarianism among SDA cuts across racial and socio-economic divisions.

Consistent with past studies, the SDA study gave vegetarians 3 extra years of life.  Note that SDA men already live 7 years longer than other Americans (4½ years for women).  So the vegetarian advantage in SDA studies is on top of a large head start.  7 years is big! comparable to the difference between Japan (world’s highest life expectancy) and Mexico (representative of the worldwide average, outside Africa which is shockingly low) [Wikipedia list]

Benefits were reported for for heart disease (especially) and selective cancers, cancers of the digestive tract in particular.  Past studies have found that cardiovascular mortality is 24% lower among vegetarians.

Gary Fraser, an MD-PhD cardiologist at SDA-affiliated Loma Linda University, has written a great deal on the health benefits of vegetarian diets.  Here is a chart from his 2009 review of SDA and other data:

 

Diet group BMI rel incidence
of Diabetes
rel incidence
of Hypertension
Nonvegetarian 28.26 1.00 1.00
Semivegetarian 27.00 0.72 0.77
Pescovegetarian 25.73 0.49 0.62
Lactoovo-vegetarian 25.48 0.39 0.45
Vegan 23.13 0.22 0.25

Look at the diabetes rates for vegans compared to non-vegarians – only 1 / 5th as high!  Diabetes contributes to all the diseases of old age.

But look at the first column, BMI.  Non-vegetarians in the study had BMI of more than 28, compared to 25 – 26 for vegetarians and 23 for vegans.  Differences of this order could easily account for the entire 3 year life expectancy advantage [Oxford study, 2009].  There are theoretical reasons why vegetable protein might be helpful in modulating the metabolism in ways that keep weight down and insulin sensitivity up.

The vegetarian advantage appears in a much reduced incidence of early death, most apparent between ages 50 and 60.  (For younger decades, the death rate for both vegetarians and meat eaters is too low to make much difference, and at older ages, the advantage of vegetarianism is gradually overtaken by genetic and other factors affecting longevity.)

Findings about the advantage of fruit and (especially) green vegetable consumption should come as no surprise.  More interesting is a paper from the SDA study devoted just to nuts.  Eating a lot of nuts contributed to a lower risk of obesity and, to a lesser extent, metabolic syndrome.  Peanuts were not as helpful as other nuts.  Personally, I find that nuts are a convenient and tasty component of a low-carb vegetarian diet.

 

The Bottom Line

If you are inclined to a vegetarian diet for poliitcal or environmental or philosophic or religious reasons, then by all means enjoy the satisfaction of knowing that you are doing your body a favor, and your diet is conducive to health and longevity.  If your diet includes meat, keep in mind that the most important things you can do are to keep your weight down and expand on vegetables, nuts and fruits, with leafy greans at the top of the list.  If you are contemplating a change, I suggest that you try a vegetarian eating style for a week or even for a day at a time as a way to expand your culinary horizons and explore how it feels to you.

11 thoughts on “Less meat, More life

  1. @Josh,

    I copy below the most updated list I’ve found on life expectancy. It’s from 2014 and the OMS. Life expectancy of women in my country is the 2nd in the world. I don’t have current data from US, but from older data it could be about 3 to 4 years more than American women. Needless to say, women here are not vegetarian, and if I’ve read your data properly (no sure) they enjoy a life expectancy comparable to SDA women

    Again, not sure if I’ve read you data well. If so, my point here is that life expectancy in US is awful for a developed country, comparing anything decent with that baseline will produce much better results, and that makes me feel unsure about the conclusion of promoting vegetarianism for life extension. Japanase women are not vegetarian either, and outlive SDA women.

    http://www.who.int/mediacentre/news/releases/2014/world-health-statistics-2014/en/

    Men Women
    Rank Country Life expectancy Rank Country Life expectancy

    1 Iceland 81.2 1 Japan 87
    2 Switzerland 80.7 2 Spain 85.1
    3 Australia 80.5 3 Switzerland 85.1
    4 Israel 80.2 4 Singapore 85.1
    5 Singapore 80.2 5 Italy 85
    6 New Zealand 80.2 6 France 84.9
    7 Italy 80.2 7 Australia 84.6
    8 Japan 80 8 Republic of Korea 84.6
    9 Sweden 80 9 Luxembourg 84.1
    10 Luxembourg 79.7 10 Portugal 8

    • Yes – Spain is doing very well, and I agree that low life expectancy in the USA is a scandal. There are many factors that go into life expectancy of a country, including genetics, culture, and quality of medical care in addition to diet. I read the studies as saying that vegetarian diets help in keeping weight down, and thereby add to life expectancy. The important thing is to eat lots of greens, rather than to avoid meat absolutely.

    • @Santiago:

      I don’t think that such national statistics do anything to refute the results of the Seventh Day Adventists Study or allow any conclusions regarding the effect of a vegetarian diet on health. The avarage life expectancy for a nation depends on a multitude of factors, diet being only one of them. In order to compare the effects of a vegetarian vs. an omivorous diet, you ideally want to have a study cohort or collective as homogenous as possible with diet being the only significant difference. There has been no other study done in nutritional epidemiology coming so close to that ideal as the Seventh Day Adventists Study. Consider that the Adventists live in closed communities and share a very similar lifestyle dominated by their religious belief, except that some of them choose to eat a vegetarian diet for religious reasons and some do not. Hence there is much less confounding from other factors – which are hard if not impossible to fully control for – than in general population studies, let alone international comparisions (e.g. people eating a vegetarian diet tend to be better educated, have a higher social status and to be overall more health-conscious; poeple in country A eat much less meat than people in country B, but they are also much poorer, have an inferior health care system, etc.).

  2. problem with vegetarism is that dementia rate is 100 percent higher.

    this may account for lower death rate 50-60 but as dementia sets in , higher death rate if older.

    they become the vegetables they eat a lot.

  3. Why do vegetarians live a few more years than meat-eaters? It might actually be quite simply lower calorie intake, some vegetarian meals do indeed have a very low calorie intake(eg: cabbage) and supposedly they burn more calories to digest then they actually supply, and meat is obviously a very compressed food in terms of the high number of calorie per volume measure it contains.

  4. Calorie restriction extends life expectancy. By restricting fats, carbohydrates and proteins separately in scientific studies, we find the increase is due to restricting protein, not fats nor carbohydrates. We can further separate proteins into some 20 amino acids. When we do that, we find that restricting the amino acid methionine causes the increase in life expectancy. Methionine is on average twice as high in meat as in vegetables. So a vegan diet is similar to a calorie restricted diet, in that it restricts methionine. One could also add to the effect by simply eating less food.
    This is the reason I am a vegan; and for no other reason.

    • I’ve written why I don’t think it’s so simple, Jerry.
      http://joshmitteldorf.scienceblog.com/2013/05/13/could-cutting-this-one-nutrient-make-you-live-longer/

      ** In animal experiments, methionine restriction only has an effect when you start to get very, very low in methionine. With calorie restriction, the benefit is linear. Every increment of calorie restriction results in about the same increment in life extension. But with methionine restriction you get no effect, no effect, no effect, and all of a sudden – bam! major life extension when methionine is down at just a few percent of ad lib levels.

      ** The CR benefit is mediated through insulin signaling. Since carbs stimulate a bigger insulin spike than fats and protein, low-carb diets can offer some of the benefit of CR.

      • interesting, but shouldn’t there be a stopping point when you are not eating enough calories to live ? I am in the process of changing my diet and I am going to try and hit the lowest possible BMI, before I am considered underweight that is roughly 18.5 . For my height 5 ft 4 inches that would be around 111 lbs.

  5. Again, south indians have amongst highest rate of diabetes in the world compared to their north indian counterparts who eat more meat, and of course we are talking about hundreds of millions of people. Of course most are allowed dairy but many abstain from lactose due to intolerance. Although not all South indians are strictly lacto-vegan , most likely they eat less meat and more carbs (ie,contrast south indian restaurant menus with north indian).

    Of course this may be different for difference races and diet may effect different races, but a meat advocate can easily inversely argue statistics in their favor also.

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