Meat may play an unexpected role in helping people reach 100

Longevity pioneers like Bryan Johnson are going to extreme lengths in the quest for immortality, but for those of us who hope to reach 100 with less commitment, dietary tweaks are typically the first port of call. Going plant-based is often recommended, but now a study in China has revealed that most centenarians there eat meat, which may be particularly helpful for those who are underweight.

Meat is a rich source of certain amino acids that seem to affect a signalling molecule called mTOR, which contributes to the ageing process. Multiple studies suggest that cutting back on meat, or eliminating it, can promote longevity, as well as reduce the risk of conditions like heart disease. On the other hand, plant-based diets have been linked to an increased incidence of fractures and malnutrition.

Such issues could be especially problematic for older people, who tend to have weaker bones and recover poorly after surgery, says Kaiyue Wang at Fudan University in Shanghai. To better understand the link between diet and longevity, Wang and her colleagues gathered data from a centralised Chinese health database on people older than 65.

Pulling from the profiles, the researchers investigated the database’s 5203 participants, who were at least 80 years old in 1998 and were free of cardiovascular disease, diabetes and cancer. Of these, about 80 per cent said they were meat-eaters, while the others said they ate plant-based diets of mostly vegetables and grains, but also sometimes non-meat animal products.

The researchers observed that the meat eaters were more likely to reach 100 than their vegetarian, pescatarian and vegan counterparts. However, this was only statistically significant when they took body weight into account.

Of the vegetarians who had a body mass index below 18.5 (defined as being underweight) in 1998, 24 per cent reached 100, compared with nearly 30 per cent of the underweight meat eaters, with the odds seeming to rise further if they reported eating meat every day. The same trend wasn’t found for people of a heavier weight.

A meat-rich diet has been linked to obesity, but research also supports animal proteins for building stronger muscles and bones, which may be particularly helpful for people who are underweight, says Wang.

Still, eating plenty of vegetables is very important, with the researchers also finding that longevity was generally higher among the participants who reported consuming any amount every day.

“Older adults may face distinct nutritional challenges,” says Wang. “Our study suggests that dietary recommendations for the oldest-old should emphasise balance and nutritional adequacy, rather than strict avoidance of animal foods, especially for underweight older adults.”

The results may not apply to other parts of the world where people have different diets. However, “the underlying biological mechanisms related to nutrition and ageing are likely universal”, says Wang.

James Webster at the University of Oxford says the findings “shouldn’t alone change the way people eat”. His team’s previous work associating vegetarianism with an increased risk of hip fracture led to some assumptions that such diets might be unhealthy. But Webster points out that multiple papers have stressed the benefits of a vegetarian diet, particularly when it comes to health.

Both vegetarian and meat-based diets can be healthy or unhealthy, depending on their nutritional quality, says Webster. “It is important to understand what nutrients are needed for a balanced, healthy lifestyle,” he says. This includes eating plenty of whole grains, fruits and vegetables, while minimising salt, sugar and saturated fats.

“Ultimately, more evidence is needed before we can be confident in saying which diet is better for living longer, but we should look at the bigger picture when thinking about dietary patterns,” says Webster.