Eight-week vegan diet linked to lower biological age, study finds

Going vegan for eight weeks was found to be linked to lowering biological age, according to a study published in the journal BioMed Central (BMC) Medicine. Researchers looked at the molecular effects of the plant-based diet that abstains from consuming animal food products, such as dairy. The diet largely includes eating fruits and vegetables, along with grains, beans and nuts.

The researchers, including those at Stanford University, US, found that consuming the plant-based diet was related with changes in how a gene expressed itself, or gene behaviour, without changing the DNA itself. Specifically, they looked at DNA methylation, known to be able to "turn off" or "silence" a gene, thereby not allowing it to express itself.

Higher levels of DNA methylation is associated with a higher biological age. It is one of the epigenetic processes, which affect the behaviour of a gene by altering its environment.

For eight weeks, the team followed 21 pairs of adult identical twins -- one half of each pair consumed an omnivorous diet, including meat, eggs and dairy, while the other consumed a vegan one. Identical twins share a significant amount of their genetic makeup.

On average, the participants were aged 40 years and had a body mass index (BMI) in the overweight category. About 77% of the group were women.

After eight weeks, the researchers observed a 'younger' heart, liver, inflammatory and metabolic system among the participants consuming the vegan diet. These changes were not seen in those eating the omnivorous diet.

However, the authors cautioned that the extent to which these changes could be attributed to their diets was unclear.

They noted that on average, the individuals on the vegan diet lost two kilograms more compared to those on the omnivorous diet. The results suggest that the weight loss could have contributed to lowering of the biological age in the vegan group, the researchers said.

Reacting to the study, Tom Sanders, a professor emeritus of Nutrition and Dietetics at King's College London, and not involved in the study, said that the findings might be favourable for vegans in terms of ageing.

However, the diet can come with micronutrient deficiencies, which often take years to exert harmful effects, Sanders said. "For example, unless a vegan diet is supplemented with vitamin B12 they develop vitamin B12 deficiency that causes chronic and often insidious damage to the nervous system," Sanders said.

Long-term studies of vegans also find adverse effects on bone density, probably caused by very low calcium and barely adequate protein intakes, Sanders said.