Longevity Briefs: The Best Diets For Longevity

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Longevity briefs provides a short summary of novel research in biology, medicine, or biotechnology that caught the attention of our researchers in Oxford, due to its potential to improve our health, wellbeing, and longevity.

The problem: When it comes to diet and longevity, we tend to overcomplicate things by focussing disproportionately on micronutrients like vitamins, minerals and antioxidant compounds. While these are undoubtedly important, it is likely that the greatest benefits come from the most simple dietary practices, which mostly boil down to eating less and eating more plants. With that being said, estimating the impact of diet on human longevity is hard because putting a group of people on a strict diet and following them up until they die isn’t really feasible. In this article, researchers attempt to review the evidence that is available and paint a picture of what a good diet for health and longevity should look like.

The discovery: Researchers found that calorie restriction (reduced calorie intake without malnutrition) was associated with improvement in biomarkers of health and longevity. The longest trial of calorie restriction lasted 2 years. In that trial, participants reduced their calorie intake by 12% and benefited from reduced blood pressure, reduced blood sugar, and other improvements in markers thought to be relevant to ageing. Unfortunately, 2 years isn’t long enough to determine whether calorie restriction reduces mortality. There is very clear evidence that weight gain is associated with more mortality and age-related diseases, but of course calorie intake is not the only factor that governs body weight.

Risk of age related diseases for a 5kg increase in weight, for young to middle aged adults. Changes in risk are expressed as odds ratios, which means the ratio of disease incidence in people who gained weight relative to those who did not. A ratio of 1 means no significant change. A ratio of 1.2 means a 20% increase in disease risk for a 5kg weight increase.
*Diet strategies for promoting healthy aging and longevity: An epidemiological perspective*

Researchers also found that both the balance and source of macronutrients (fat, protein and carbohydrates) were associated with longevity:

Consumption of trans and saturated fatty acids is associated with higher mortality, while unsaturated fatty acids are associated with reduced mortality.
High consumption of animal-based proteins is associated with greater mortality while consumption of plant-based protein is not.
Low carbohydrate diets are associated with improved biomarkers of ageing (such as reduced blood sugar), but only if carbohydrates are replaced with plant-based fat and protein.
Consumption of polyphenol-rich foods such as coffee, tea, extra virgin olive oil and blueberries is associated with improved biomarkers of ageing as well as health benefits like improved cognitive function and cardiovascular health.

Change in total mortality according to the percentage of total calories derived from different types of fat.
*Diet strategies for promoting healthy aging and longevity: An epidemiological perspective*

The implications: Putting this all together, a slightly calorie restricted diet with a focus on plants, especially those rich in polyphenols, seems to be a good baseline for a longevity-optimised diet. As noted by the authors, the Mediterranean, Nordic, Okinawan and vegetarian diets all fit the bill and are all associated with higher life expectancy and reduced risk of age-related disease. However, we shouldn’t forget that diet is only one piece of the puzzle and that a healthy diet synergises with other healthy practices. There is evidence that both exercise and good quality sleep can enhance the benefits gained from a healthy diet.