A study published in the journal BioMed Central (BMC) Medicine found that following a vegan diet for eight weeks is associated with a reduction in biological age. The researchers examined the molecular impact of a plant-based diet that excludes animal products, including dairy. This diet primarily consists of fruits, vegetables, grains, beans, and nuts.
Researchers, including a team from Stanford University in the US, discovered that following a plant-based diet was associated with changes in gene expression or behaviour, without altering the DNA itself. They focused on DNA methylation, a process known to "turn off" or "silence" a gene, preventing it from expressing.
Higher levels of DNA methylation are 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 research team observed 21 pairs of adult identical twins. In each pair, one twin followed an omnivorous diet, including meat, eggs, and dairy, while the other followed a vegan diet. Identical twins share a considerable portion of their genetic makeup. The participants were, on average, 40 years old and had a body mass index (BMI) in the overweight range. Approximately 77 per cent of the group were women.
After eight
weeks, researchers noted that participants on a vegan diet exhibited a 'younger' heart, liver, as well as improved inflammatory and metabolic systems. These improvements were not observed in those following an omnivorous diet. Nonetheless, the authors warned that it was uncertain how much of these changes could be directly linked to their diet.
The researchers observed that, on average, individuals following the vegan diet lost two kilograms more than those on the omnivorous diet. They suggested that this weight loss might have played a role in the reduction of biological age in the vegan group.
Tom Sanders, a professor emeritus of Nutrition and Dietetics at King's College London who was not involved in the study, commented that the results could be beneficial for vegans in relation to ageing. However, he cautioned that the vegan diet might lead to micronutrient deficiencies, which can take years to manifest their adverse effects.
"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.