Eating a vegan diet for just TWO months may reduce a person's biological age and help them lose weight, scientists say

Eating a vegan diet for just eight weeks may reduce a person's biological age and help them lose weight, a study suggests.

Volunteers who were restricted to just plant-based foods also achieved decreases in the ages of the heart, hormone, liver, and inflammatory and metabolic systems.

However, these changes were not seen in participants whose diet included meat, eggs, and dairy, according to researchers at Stanford University, California.

Those who ate a vegan diet over the course of the study lost two kilograms more on average than those who did not.

However, this is likely due to them consuming 200 fewer calories a day in the meals provided over the first four weeks.

Experts say the weight loss could have contributed to the observed differences in biological age between the two groups, rather than the nature of the food itself.

Some suggest that, long-term, a vegan diet may result in nutritional deficiencies and may not suit all ages.

The findings, published in the journal BMC Medicine, are based on a small study of 21 pairs of identical twins aged 39, half of whom ate a vegan diet, while the other sibling ate an omnivorous diet.

By the end of the study, the researchers observed decreases in biological age estimations based on levels of DNA methylation - a type of chemical modification of DNA that is used to estimate biological age.

Biological aging refers to the decline in functioning of tissues and cells in the body, as opposed to chronological age.

Previous research has reported that increased DNA methylation levels are associated with aging.

However, Varun Dwaraka, of epigenetic testing company TruDiagnostic Inc, and Christopher Gardner of Stanford University, California, and colleagues, said it is unclear how much the differences between the pairs can be attributed to the differences in diet.

Further research is needed to investigate the relationship between diet, weight and aging, in addition to the long-term effects of vegan diets, they add.

Tom Sanders, Professor emeritus of Nutrition and Dietetics, King's College London, who was not involved in the study, said the research found some difference in terms of aging for vegans, but does not consider the fact that vitamin and mineral deficiencies often take years to appear.

He added that research also suggests a vegan diet may not be good for the health of older people.

Professor Sanders said: 'Although observational studies indicate that vegan diets may have favourable effects on health in middle age (such as a lower risk of cardiovascular disease and type 2 diabetes), this is not the case in older vegans who 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.' 

Dr Duane Mellor, dietitian and spokesman for British Dietetic Association, said that although the study compared a vegan diet to an omnivorous diet, these diets were not entirely matched in terms of calories.

He added: 'It is possible that a reduction in energy intake could potentially have altered how the participants' DNA was changed.' 

Dr Mellor highlighted the vegan group were asked to eat twice the number of portions of vegetables, more fruit and more legumes, nuts and seeds than the omnivore group, which also could in part explain the differences reported.