Eating an abundance of fruits and vegetables is associated with a host of health benefits, but is going meatless really the best way to increase your odds of living a long life? In this article, I will discuss data on longevity which compares the lifespans of vegetarians and non-vegetarians. Read on to learn more about what the data has to say about which group is more likely to die from cancer, cardiovascular disease, and other causes of death, and how important diet really is if your goal is to live to 100 years (and beyond!). If you prefer to listen to the article, click here.
Is cutting out meat the path to the fountain of youth? Spoiler: maybe not.
I will focus on three sources of data:
The Adventist Health Study 2, which was done in the United States,
The European Prospective Investigation into Cancer and Nutrition (EPIC) Oxford study, which was done in the United Kingdom, and
Research on the Blue Zones, which is not a rigorous research study like the first two, but includes observational findings from 5 areas around the world where people live unusually long.
Topic 1: The Adventist Health Study (AHS) 2
This research study is an example of what is called a longitudinal study or a cohort study. This study design is beneficial for trying to understand differences in health outcomes for conditions that can take decades to develop, such as cancer and cardiovascular disease. These studies are very costly and time intensive on the part of both the researchers and the research participants, but the fruits of several years' worth of data collection are worth it. To carry these studies out, researchers basically gather up a large number of people and follow then for several years, periodically having the study subjects come into the research center for data collection. For outcomes where the subjects may not be able to come in themselves, such as in cases of death, large databases like the ones provided by the Centers for Medicare and Medicaid are used to gather follow-up data from willing research participants.
Fun fact: some of these cohort studies last so long that the researchers die before the final results are published!
Recruitment for the AHS-2 took place from 2002-2007 in the United States and Canada. The 70,000 study participants were all members of the Seventh-day Adventist community. These men and women were followed for about 6 years, and based on their diet, they were placed into one of five categories: non-vegetarians, semi-vegetarians (people who ate meat at least once per month), pesco-vegetarians (vegetarians who eat fish - although their inclusion in the club is debatable), lacto-ovo–vegetarians (vegetarians who eat dairy and eggs), and vegans. After controlling for other variables which can affect mortality like education and smoking, the researchers found that compared to non-vegetarians, when grouped together, vegetarians did generally outlive meat-eaters. But don’t celebrate just yet, my fellow vegetarians – there is more to this research story.
Interestingly, when the cohort was split into males and females, the results differed. Vegetarian men still were found to live longer than non-vegetarian men, but vegetarian women were not found to outlive their meat-eating counterparts. There are a number of potential explanations for why women did not seem to enjoy the same benefits as men from following a vegetarian diet, but I will save that for another article.
Sorry, ladies.
The researchers also looked at mortality from several specific causes based on the type of vegetarian diet that a person followed. This is where the findings get even more interesting. Using non-vegetarians as the comparison group for vegans, lacto-ovo vegetarians, pesco-vegetarians, and semi-vegetarians, pesco-vegetarians actually fared the best for several outcomes; they had lower rates of death from ischemic heart disease and all-cause mortality, which is just a catch-all term for dying in general. Both pesco-vegetarians and vegans fared best for the outcome of non-cardiovascular and non-cancer deaths, such as deaths from kidney failure or infectious disease. Lacto-ovo and semi-vegetarians did not fare better than omnivores for any cause of death. So basically, pesco-vegetarians were the only group of vegetarians that consistently had lower rates of death from any given cause when compared to non-vegetarians.
Go ahead, order that second plate of sushi.
When the researchers again divided the dataset by sex, they found that men who followed a vegan, lacto-ovo, or pescatarian diet died less often from cardiovascular disease than men who didn't. Veganism was also beneficial for reducing the risk of death from ischemic heart disease and all-cause mortality, while being a pescatarian was protective against all-cause mortality and other non-heart, non-cancer related deaths. For women, the only protective association found was for pesco-vegetarians, who were less likely than omnivores to die from ischemic heart disease. Vegan, lacto-ovo vegetarian, and semi-vegetarian women had similar lifespans to non-vegetarian women.
Vegetarian women did not fare better than non-vegetarian women for mortality related to infectious disease, neurological conditions, respiratory illness, renal failure, or illnesses of the endocrine system. Vegetarian men on the other hand did fare better than men who ate meat on the latter two outcomes. No associations between diet and cancer mortality were found in this study.
All in all, it seems that while various forms of vegetarianism were protective against mortality particularly for men, less strict vegetarianism, specifically pesco-vegetarianism was especially beneficial for women.
There better be some fish outside the frame, dad.
Topic 2: European Prospective Investigation into Cancer and Nutrition (EPIC) Oxford Study
Over in the United Kingdom, researchers have also been looking at how mortality outcomes may differ depending on diet type. There are two studies from the 80s and 90s whose data was combined to test this association: The Oxford Vegetarian Study and The European Prospective Investigation into Cancer and Nutrition, commonly shortened to EPIC-Oxford study.
Researchers looked at outcomes for over 60,000 people and placed people into four categories: regular meat eaters (people who ate meat 5 or more times per week), low meat eaters (those who ate meat less than 5 times per week), fish eaters, vegetarians, and vegans. They found that fish-eaters were the only group with significantly fewer deaths from malignant cancer, and that low meat eaters were the only ones who died less from respiratory diseases. Vegans and vegetarians did not die less often than non-vegetarians from ischemic heart disease or cardiovascular disease, but they were protected against malignant pancreatic cancer.
In 2017, a meta-analysis was published wherein researchers put together data from several different studies that each looked at several health outcomes for vegans and vegetarians. What is a meta-analysis, you ask? Well, a meta-analysis is a fancy and complex way of pooling together large amounts of data on the same topic in order to generate more statistical power and increases the chances of detecting any significant associations in the dataset – if there are any to be found.
Pooling together the research that has been done on the relationship between diet and causes of death, the researchers were able to conclude that there is an overall trend that favors lower mortality for vegans and vegetarians, but in most cases, the results were not statistically significant. This means that the mortality outcomes for non-vegetarians were generally no different from those of vegetarians.
Enjoy that chicken - including some meat in your diet may actually be good for you.
Taken together, the results of these extensive scientific studies suggest that strict vegetarianism is not necessarily associated with a longer lifespan.
Topic 3: The Blue Zones
Lastly, let’s look at data from the Blue Zones. Unlike the AHS-2 and the EPIC-Oxford studies, the findings from the Blue Zones did not come as a result of rigorous research and data analysis. Rather, this data is purely observational in nature. Still, it is worth taking a closer look at.
First, what are the Blue Zones? They are five locations in the world with an unusually high number of centenarians, or people who make it to their 100th birthday. These five locations are: Okinawa, Japan, Sardinia, Italy, Nicoya, Costa Rica, Ikaria, Greece, and Loma Linda, California.
The work done to assess what makes these people live so long by Gianni Pes, Michel Poulain, and Dan Buettner implies that there are a total of nine factors which these communities all have in common that help them to live long, healthy lives:
These factors are:
Having a sense of community
Moving about naturally, i.e. not going to the gym, but incorporating movement into their day to day lives
Having a purpose in life
Putting loved ones first
Being surrounded by people with similar goals and values
Having wine in the evening
Following the 80% rule, which means that they stop eating when they feel 80% full
Having stress management routines
And having a mostly plant-based diet
Community is a huge factor when it comes to living long in the Blue Zones.
Notice that I said a mostly plant-based diet. People living in the Blue Zones all have a tendency to eat less meat than your average Westerner, but they are not exclusively vegetarian. In Okinawa, Japan, people traditionally eat a diet rich in plant foods with small quantities of pork and fish. In Sardinia, Italy, it is customary to eat small amounts of meat, fish, and poultry, and to have lots of sheep and goat milk. In Nicoya, Costa Rica, small amounts of meat are customarily consumed as well. In Ikaria, Greece, meat and fish make up a little over 10% of their Mediterranean-style diet. Finally, the Adventists of Loma Linda, California, which are the same group from the AHS-2 study, are about 50% vegetarian, and 50% non-vegetarian.
Across nations, meat intake was limited on average to a little over 1 serving per week. On a personal note, this is something that my mother loves to remind us of from her childhood in Antigua, and that I have heard other older folks of different nationalities say; just a few decades ago, meat used to be a special food that was eaten once a week, as it was expensive and in some cases, involved sacrificing one’s own animal. Could it be that the secret to living longer and healthier lives lies in eating less meat as our parents and grandparents did, rather than cutting it out completely? The implications of such a cultural shift could benefit not only our health, but that of the planet too. What do you think?
If you had to slaughter your meat in order to eat it, would you eat meat every day?
Conclusion
Altogether, the data suggests that vegetarians do not necessarily outlive non-vegetarians. For women in particular, eating some amount of fish may be better than abstaining from meat completely.
It is also important to remember that living into old age is a matter not just of what you eat, but also of the many other lifestyle choices that you make which contribute to the quality of your life. To this end, I really like the Japanese concept of Ikigai, which is about finding a personal meaning for your life based on what you are passionate about, what you can be paid for, what you are good at doing, and what the world needs.
If you learned anything new or think that someone you care about could benefit from this information, share this article, and subscribe to the blog for regular updates on commonly asked nutrition questions.
References:
Dinu, M., Abbate, R., Gensini, G. F., Casini, A., Sofi, F. (2017). Vegetarian, Vegan Diets and Multiple Health Outcomes: A Systematic Review with Meta-analysis of Observational Studies. Critical Reviews in Food Science and Nutrition, 57(17):3640-3649. doi: 10.1080/10408398.2016.
Orlich, M. J., Singh, P. N., Sabaté, J., Jaceldo-Siegl, K., Fan, J., Knutsen, S., Beeson, W. L., Fraser, G. E. (2013). Vegetarian Dietary Patterns and Mortality in Adventist Health Study 2. JAMA Internal Medicine, 173(13):1230-8. doi: 10.1001/jamainternmed.2013.6473.
Appleby, P. N., Crowe, F. L., Bradbury, K. E., Travis, R. C., Key, T. J. (2015). Mortality in Vegetarians and Comparable Nonvegetarians in the United Kingdom. American Journal of Clinical Nutrition, 103(1):218-30. doi: 10.3945/ajcn.115.119461.
The Blue Zones Story - Blue Zones. (2015). Blue Zones. https://www.bluezones.com/
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