Restricting your diet to plant-based foods may reduce your biological age, at least that’s what a study suggests.
Researchers at Stanford University in California who analyzed pairs of twins found that those who ate a vegan diet for two months had fewer signs of aging in their DNA compared to those who maintained an omnivorous diet.
But independent experts have warned that the findings may not be all they seem and that cutting out animal products could leave us suffering from a range of deficiencies in the long term.
They highlighted a number of factors and flaws in the study that could explain or influence the findings.
Critically, they also said other studies have shown that vegans enjoy no increase in life expectancy compared to omnivores.
While eating more vegetables has a host of benefits, giving up meat, fish, eggs and dairy products could put you at risk of long-term nutritional deficiencies, warns Tom Sanders, emeritus professor of nutrition and dietetics at King’s College London.
Professor Tom Sander, an expert in nutrition and dietetics at King’s College London, was one of the experts who pointed out problems with the study’s findings on veganism reducing biological ageing.
He noted that the study’s relatively short follow-up time of just two months could not account for the damage that prolonged veganism could cause to the body.
“For example, unless a vegan diet is supplemented with vitamin B12, a vitamin B12 deficiency develops, causing chronic and often insidious damage to the nervous system,” he said.
‘Long-term observational studies in vegans also find adverse effects on bone density, likely caused by very low calcium and marginally adequate protein intakes.’
Vitamin B12 is necessary to maintain both the blood and nervous system healthy.
It is abundant in meat, fish and dairy products, meaning most people don’t need to worry about it, but vegans may be at risk of deficiency.
On the other hand, calcium, of which dairy products are a rich source, is vital for maintaining healthy bones and teeth and a lack of it can lead to brittle bones.
Professor Sander added that the deficiencies were of particular concern to older vegans, who could suffer serious health problems as a result of their diet.
“While observational studies indicate that vegan diets may have favorable health effects in midlife, such as a lower risk of cardiovascular disease and type 2 diabetes, this is not the case for older vegans who appear more likely to suffer from muscle loss, low bone density and neurological disorders that have a significant impact on quality of life,” she said.
He added that other work had shown that vegans did not appear to enjoy any increase in overall longevity compared to omnivores.
“Life expectancy does not differ between vegans and those who opt for mixed diets,” he said.
Dr Duane Mellor, a dietitian and spokesman for the British Dietetic Association, added that it was important to remember that other aspects of the study could be behind the observed reductions in biosupport in participants who followed a vegan diet.
“Although the study compared a vegan diet with an omnivorous diet, these diets were not completely matched, with vegan participants consuming on average around 200 kcal less per day, resulting in an average weight loss of 2 kg,” she said.
Researchers at Stanford University in California found that volunteers who ate a vegan diet for just eight weeks had fewer signs of aging compared to those who followed an omnivorous diet.
‘It is possible that a reduction in energy intake could have potentially altered the way the participants’ DNA was modified.
‘Another important consideration was that the vegan group was asked to eat twice as many servings of vegetables, more fruit, and more legumes, nuts and seeds than the omnivore group.
‘This was partly to replace meat, eggs and dairy products, but this would mean that fibre intake, as well as vitamin and mineral intake, would likely be different between the groups, which could also partly explain the reported differences.’
He added that the omnivorous cohort in the study group was also asked to eat a substantial amount of meat, which could potentially exaggerate the differences.
‘Omnivores were asked to eat between 6 and 8 oz (175 and 225 g) of meat per day, which seems like a lot compared to UK recommendations, although this was total meat and not just red meat – 70 to 90 g per day.
Overall, Dr Mellor said the changes seen in participants’ DNA were “theoretical” and not directly linked to longer life.
She advised: ‘The key to 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 whole grains and if you want to consume them moderate amounts of meat and dairy.
‘If you do not wish to consume animal products, then you should include in your diet alternative sources of nutrients including iodine, iron, calcium and vitamins B12 and D, as well as a source of omega-3 fatty acids.’
Professor Sanders says older vegans are more likely to suffer from muscle loss, low bone density and neurological disorders (file image)
The findings of the new study, published in the journal BMC Medicine, are based on a small study of 21 pairs of identical twins aged 39.
One pair of each set of twins was given a vegan diet, while the other was given an omnivorous diet.
At the end of the study, researchers observed decreases in estimates of biological age based on levels of DNA methylation, a type of chemical modification to DNA used to estimate biological age.
Biological aging refers to the deterioration in the functioning of the body’s tissues and cells or, in other words, the appearance of the body.
This is opposed to chronological age, which is the number of years a person is.
Previous research has reported that increased DNA methylation levels are associated with aging.
The authors of the new study, Varun Dwaraka of epigenetic testing company TruDiagnostic Inc. and Christopher Gardner of Stanford University in California and their colleagues, also acknowledged that their findings had limitations.
They said it was unclear to what extent differences between couples could be attributed to differences in diet.
WHAT SHOULD A BALANCED DIET LOOK LIKE?
The average woman is advised to consume 2,000 a day to maintain a healthy weight and one-third of the 2,500 recommended for the typical man.
• Eat at least 5 servings of a variety of fruits and vegetables every day. Fresh, frozen, dried and canned fruits and vegetables all count.
• Base meals on potatoes, bread, rice, pasta or other starchy carbohydrates, ideally whole grains.
• 30 grams of fiber per day: This is the same as eating all of the following: 5 servings of fruits and vegetables, 2 whole grain crackers, 2 thick slices of whole wheat bread, and one large baked potato with skin.
• Eat some dairy products or dairy alternatives (such as soy drinks) and choose lower-fat and lower-sugar options.
• Eat some legumes, fish, eggs, meat and other proteins (including 2 portions of fish per week, one of which should be fatty)
• Choose unsaturated oils and creams and consume in small quantities.
• Drink 6 to 8 cups/glasses of water a day.
• Adults should consume less than 6 g of salt and 20 g of saturated fat for women or 30 g for men per day.
Fountain: NHS Healthy Eating Guide