Skinny gene raises risk of diseases

An international team from 72 institutions in 10 countries has found that the link is particularly strong in men, meaning those with washboard stomachs may not be quite as healthy as they think, the ‘Daily Mail’ reported.

For their research, the scientists compared the genetic codes of more than 75,000 people with the ratio of fat to muscle in their bodies. This revealed an extremely common gene called IRS1 to be linked to leanness. But while people are used to hear about  many health benefits of being thin, IRS1 seemed to buck the trend. Those with the gene had higher levels of dangerous blood fats and found it harder to process sugar, say the scientists.

This put them at a 20 per cent higher risk of developing heart disease and type-2 diabetes — the form that develops in middle age and is often blamed on obesity. As the gene is only linked to lower levels of fat stored just below the skin, known as subcutaneous fat, it may be that people who have IRS1 stash theirs elsewhere.

If fat is wrapped around the heart, liver or other organs it could lead to life-threatening conditions, says the team.  Lead scientist Dr Ruth Loos of the MRC Epidemiology Unit in Cambridge, said: “People, particularly men, with a specific form of the gene are more likely to be lean and to develop heart disease and type-2 diabetes.

“In simple terms, it is not only overweight individuals who can be predisposed for these diseases, and lean individuals shouldn’t make assumptions that they are healthy based on their appearance.”

The scientists suggested that the effects may be more pronounced in men because they store less fat than women, and could be more sensitive to changes in its distribution. Professor Nick Wareham, the unit’s director, added: “The research will provide new insights into  why not all lean people are healthy and, conversely, why not all overweight people are at risk of metabolic diseases.” Experts have welcomed the findings published in the latest edition of the ‘Nature Genetics’ journal.

Prof Jeremy Pearson of the British Heart Foundation said: “These results reinforce the idea that it is not just how fat you are, but where you lay down fat that’s particularly important for heart risk. Fat stored internally is worse for you than fat stored under the skin.”  So it’s not the size but gene that really matters.