Are animal products essentially for a healthy and long human life?

Purpose of review: Plant-based diets are associated with better health and longevity. Veganism is a strict form of vegetarianism, which has gained increasing attention in recent years. This review will focus on studies addressing mortality and health-span in vegans and vegetarians and discuss possible longevity-enhancing mechanisms.

Recent findings: Studies in vegans are still limited. Epidemiologic studies consistently show lower disease rates, such as lower incidence of cancer and cardiovascular disease, but mortality rates are comparable with rates in vegetarians and occasional meat eaters. Reasons for following strict vegan diets differ, which may affect diet quality, and thus health and life-span. New insights into some characteristics of veganism, such as protein restriction or restriction in certain amino acids (leucine or methionine) show potentially life-span-enhancing potential. Veganism improves insulin resistance and dyslipidemia and associated abnormalities. Gut microbiota as mediator of dietary impact on host metabolism is more diverse in vegans and has been suggested to be a health-promoting factor. Vegan diets do not fulfill the requirements of children, pregnant women or old individuals who should receive adequate supplements.

Summary: There is substantial evidence that plant-based diets are associated with better health but not necessarily lower mortality rates. The exact mechanisms of health promotion by vegan diets are still not entirely clear but most likely multifactorial. Reasons for and quality of the vegan diet should be assessed in longevity studie

As previous chapters demonstrated, vegans have a lower risk of many diseases and have a higher intake of protective plant foods so it follows that their overall longevity should be above the average age. Orlich et al. (2013) investigated dietary patterns and mortality rates in a large American and Canadian population. They found that vegans had 15 per cent lower all-cause mortality compared with meat-eaters.

In another large study, this time of a Spanish population, the authors looked at dietary patterns and many types of food in particular in relation to mortality (Martínez-González et al., 2014). They found that people whose diets contained the most fruit, vegetables, nuts, cereals, pulses, olive oil and potatoes and minimal amounts of animal fats, eggs, fish, dairy products and meats or meat products had significantly lower mortality. In fact, people whose diets were the most plant-based had mortality rates 41 per cent lower than the rest of the population. That means that over the course of the study, people whose diets were mostly vegan were healthier and much fewer of them died compared to the rest of the population.

And finally, the EPIC study that included more than 450,000 participants to study their dietary habits and mortality came to a similar conclusion (Leenders et al., 2014).  People consuming more than 570 g of fruits and vegetables a day had lower risks of death from diseases of the circulatory, respiratory and digestive system when compared with participants consuming less than 250 g a day. In more detailed analyses, raw vegetable consumption was showing an even stronger association with lower mortality rates.

The overall message is clear - these studies agree that vegans live longer, healthier lives.