Reducing calorie intake may slow the ageing process

Eating around 12 percent less appears to slow the acquisition of epigenetic markers associated with ageing in humans, according to new research.

Previous studies on worms, flies and mice have all shown that calorie restriction can extend healthy lifespan, but this has been much harder to test in humans, for ethical and practical reasons. Instead, researchers looked at epigenetic markers associated with ageing, specifically DNA methylation in blood samples.

'Humans live a long time, so it isn't practical to follow them until we see differences in ageing-related disease or survival,' said senior author Dr Daniel Belsky from Columbia University in New York.
'Instead, we rely on biomarkers developed to measure the pace and progress of biological aging over the duration of the study.'

DNA methylation refers to natural modifications to the surface of DNA that alter gene expression. Methylation patterns can be influenced by several factors, including age, ethnicity and diet.

The study, published in Nature Aging, used algorithms to look at DNA methylation associated with ageing, and the pace at which they were acquired.

Around 200 healthy participants aged between 21-50 with BMIs between 22-27.9 took part in the CALERIE clinical trial. They were randomly assigned to the calorie restriction group, who aimed to eat 25 percent less than normal, or the control group who normally. The 128 participants in the calorie restriction group achieved an average calorie restriction of 12 percent after 24 months.

Researchers analysed blood DNA methylation patterns of the trial participants after 12 and 24 months. The pace at which the age-associated signatures were acquired was 2-3 percent slower in the calorie restriction group than the controls. Furthermore, the members of the calorie restriction group who achieved greater calorie restriction (over 10 percent) showed a slower pace of change than those who did not.

Although the changes seen were small, study authors suggested that wider application of calorie restriction could have 'profound effects on population health', and suggested the use of methylation biomarkers could be applicable to studies of other dietary approaches such as intermittent fasting.

'Our findings are important because they provide evidence from a randomised trial that slowing human ageing may be possible, ' said co-lead author, Dr Calen Ryan.

Dr Duane Mellor from Aston University who was not involved in the study called the research 'interesting', but said: 'It is important to be cautious and not encourage especially older adults just to reduce their food intake to slow ageing … Maintaining a healthy weight, being physically active and eating a varied and healthy diet with enough protein is known to reduce the risk of falls.'