It would be nice if that were true I guess; that veganism was somehow the 'fountain of youth'. It's something that I've seen repeated a lot by both vegetarians and vegans, as well as on some 'green living' websites. In this post I'll go through the studies that have been done on vegetarians, vegans and how long they live, as well as look at some of the possible reasons for the findings.
Most of what I've seen said online seems to be based on a study by Fraser (1999). In this study, vegetarian Seventh-day Adventists were found to live about 2.5-3.2 years longer than their non-vegetarian counterparts. This study is not the only one to show such a link. A meta-analysis of 7 studies found that mortality rates were 9% lower in vegetarians (Huang et al 2012). Kendler's (2003) book review of “Vegetarian nutrition” stated that five out of six studies showed people with low meat intakes having lower mortality rates. This does not mean that the same results will be found for vegan diets, although vegans were included amongst the vegetarians in the studies that were analysed. There are also other factors at play beyond diet that may influence the outcomes of these studies, such as smoking. Kendler (2003) mentioned that 'several' studies controlled for factors such as smoking, alcohol consumption and physical activity and still got similar results though. This means that there may, in fact, be a link. However, none seemed to go into processed foods versus whole foods, which may also have an effect.
A 2013 study by Rohrmann et al indicated that high red meat consumption and high processed meat consumption were both linked with higher mortality rates. However, consumption of chicken flesh seemed to have no such association. Links between red meat consumption and increased chance of death are not uncommon and are usually due to a higher chance of cardiovascular disease (heart problems), diabetes and cancer (Cross 2012; Pan et al 2012). By reducing the amount of red meat eaten however, it seems that these effects can be managed. There are differences in how different kinds of meat effect a person's health, which are also influenced by the amount of meat consumed. Then again, a study that involved 17, 611 people indicated no mortality rate association with meat consumption, no matter the type of meat (Kappeler, Eichholzer & Rohrmann 2013).
Another meta-analysis of a few studies indicated no or little difference between mortality rates of vegetarians (including vegans) and “health conscious” non-vegetarians (Ginter 2008). It was suggested that it was the higher consumption of antioxidants and healthy foods, along with a lower overall consumption, that was the cause for the longevity that is talked about (Ginter 2008). The study on Seventh-day Adventists (Fraser 1999) also leant towards this conclusion; “It is important to note that vegetarians may have lower disease risk because of their lack of meat consumption, but it is equally possible that this protection could be due to increased consumption of fruits, vegetables, or nuts. Upon multivariate analysis, the latter often appeared to be the case.”
Genetics may play a part in longevity (Perls & Terry 2003), as might calorie restriction (Omodei & Fontana 2011; Roth & Polotsky 2012). Yet another study has indicated that there are no significant lifestyle factor differences between people who live longer (BMI, exercise, alcohol consumption and calorie intake) (Rajpathak et al 2011).
The link between longevity and diet seems rather complex, with a variety of factors coming in to play. There is evidence to support the idea that vegetarians (and, maybe, vegans) live longer than non-vegetarians. There is, however, also a small amount of evidence of no difference between the groups. It seems that a variety of things, such as calorie restriction, genetics and the protective properties of plant-based foods, might be the reason that people on vegetarian or vegan diets appear to live longer. It may be that small amounts of unprocessed meat can be eaten with a healthy diet and lifestyle while maintaining the same length of life as a vegetarian or vegan with a healthy lifestyle. There seems to be some conflicting evidence, but also some strong trends. It is definitely an interesting subject and I look forward to reading more studies.
A big thank you to my friends for proof-reading my posts.
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