Can a plant-based diet really reduce biological age?

A plant-based diet could lower biological age in as little as eight weeks, according to a recent study published in BMC Medicine.

The diet intervention trial, which involved 21 pairs of identical twins, compared the effects of a vegan or plant-based diet versus an omnivorous diet on biological age estimates, a tool used to gauge both overall health and the risk of age-related diseases such as heart disease and Alzheimer’s.

Biological age was calculated by measuring DNA methylation levels, a type of epigenetic chemical change that influences gene expression without altering DNA and which has been linked to ageing in earlier studies.

According to researchers at Stanford Prevention Research Center and epigenetic testing lab TruDiagnostic, only those twins following a vegan diet showed significant reductions in their epigenetic age using this metric, while their sibling on an omnivorous diet did not.

In fact, those following a vegan diet saw a decrease in the biological age across five organ systems, including the heart, hormonal, liver inflammatory and metabolic systems.

‘Exact mechanism’ unclearThe study’s authors have said the ‘surprising’ results show diet can have a more rapid impact on epigenetic health than previously thought, with many previous trials examining the effects after several months.

And though, they say, more research is needed to understand exactly what elements of a plant-based diet make the biggest difference, it’s likely that a higher-than-average consumption of fruits, vegetables, whole grains, legumes, nuts and seeds could be a key contributing factor.

Vegan diets typically include a lower intake of calories, saturated fat and processed foods, they point out, alongside higher fibre consumption, antioxidants and phytochemicals. This combination promotes a lower BMI and overall body fat, healthier gut microbiome and reduced inflammation – all which have been linked to the risk of age-related diseases.

‘The exact mechanism of how these diets are providing benefits might turn out to be through multiple different pathways in the body but the fact that they are providing benefits is very clear to us,’ said Raghav Sehgal, a PhD candidate in Computational Biology and Bioinformatics at Yale University, scientific advisor at TruDiagnostic, and Director of Bioinformatics at the Healthy Longevity Clinic.

Missing out long-term impact Other experts have urged caution in interpreting the results of the study, however.

“This is a small study conducted in twins one of whom was allocated to a vegan diet and the other to a mixed diet for two months,” says Tom Sanders, professor emeritus of nutrition and dietetics at King’s College London. “Measurement of some biological markers of ageing such as telomere length and methylation of DNA were made. The report found some difference which might be favourable in terms of ageing for vegans.

“However, this assertion does not consider the fact that micronutrient deficiencies often take years to exert harmful effects,” he points out. “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. Long-term observational studies of vegans also find adverse effects on bone density that is probably caused by very low calcium and marginally adequate protein intakes.”

In fact, though studies have shown a lower risk of heart disease and type 2 diabetes among those in middle age following a plant-based diet, older vegans “seem more likely to suffer from muscle loss, low bone density and neurological disorders which have a significant impact on the quality of life. Indeed, life-expectancy does not differ in vegans compared with those who select mixed diets.”

The findings don’t unequivocally prove that a vegan diet is healthier than an omnivorous or mixed diet, adds Dr Duane Mellor, dietitian and spokesperson for the British Dietetic Association. “The changes due to the diet could be down to the vegan group eating more plants. “The key for any diet with or without animal products is that it is made up of a wide range of foods, including vegetables, fruits, nuts, seeds, beans, peas and lentils with wholegrain and if you want to consume them moderate amounts of meat and dairy.”

Sourced From: BMC Medicine
‘Unveiling the epigenetic impact of vegan vs. omnivorous diets on aging: insights from the Twins Nutrition Study (TwiNS)’
Published on: 29 July 2024
Doi: https://doi.org/10.1186/s12916-024-03513-w
Authors: V. B. Dwaraka, L. Aronica, N. Carreras-Gallo, J. L. Robinson, T. Hennings, M. M. Carter, M. J. Corley, A. Lin, L. Turner, R. Smith, T. L. Mendez, H. Went, E. R. Ebel, E. D. Sonnenburg, J. L. Sonnenburg & C. D. Gardner