London, 4 November (IBNS): Some genetic variations associated with obesity actually prevent type 2 diabetes, heart attack and stroke.
Experts believe that where people store excess fat in the body, be it in the middle or around the liver, is genetically determined.
Exactly where extra fat is stored depends on insulin resistance and the risk of diabetes and other diseases.
Now, 14 new genetic variants that determine where the body stores excess fat have been identified by scientists across Europe, including Brunel University London and the University of Exeter. And surprisingly, some genetic factors that increase obesity reduce the metabolic risk.
"Where fat is stored is more important than the actual amount of fat in terms of diabetes risk or other consequences," said Professor Alex Blakemore, a geneticist at Brunel.
"There are some genetic factors that increase obesity, but paradoxically reduce the metabolic risk. It has to do with where on the body the fat is stored. Directly under the skin is better than the organs or especially in the liver.
The team examined UK biobank data from more than 500,000 people between the ages of 37 and 73 years. They used MRI scans (magnetic resonance imaging) on the waist to compare where they had stored extra fat, whether they showed signs of type 2 diabetes, heart attack and stroke risk.
They found 14 genetic variations or changes in the DNA molecule associated with higher body mass index (BMI) but lower risk of diabetes, lower blood pressure, and lower risk of heart disease. The study in the journal Diabetes has shown that people who carry these genetic factors are safely stored under the skin with increasing weight and thus have less fat in their major organs such as the liver, pancreas and kidneys.
"There are many overweight or obese individuals who do not bring the expected metabolic disease risks associated with a higher BMI," said Drs. Hanieh Yaghootkar from the University of Exeter Medical School. "Meanwhile, some lean or normal-weight individuals develop diseases like type 2 diabetes.
"Since a large proportion of many populations are overweight or obese, our findings will help understand the mechanisms that delay or prevent overweight or obese individuals from developing unwanted metabolic effects such as type 2 diabetes, heart disease, and hypertension."