Even modest weight gain harms blood vessels

Mayo Clinic researchers found that healthy young people who put on as little as 9 pounds of fat, specifically in the abdomen, are at risk for developing endothelial cell dysfunction. Endothelial cells line the blood vessels and control the ability of the vessels to expand and contract.

For the study, which was published in this week's Journal of the American College of Cardiology, researchers recruited healthy Mayo Clinic volunteers with a mean age of 29 years. They were tested for endothelial dysfunction by measuring the blood flow through their arm arteries. The volunteers were assigned to either gain weight or maintain their weight for eight weeks, and their blood flow was tested. The weight-gainers then lost the weight and were tested again.

Among those who gained weight in their abdomens (known as visceral fat), even though their blood pressure remained healthy, researchers found that the regulation of blood flow through their arm arteries was impaired due to endothelial dysfunction. Once the volunteers lost the weight, the blood flow recovered. Blood flow regulation was unchanged in the weight-maintainers and was less affected among those who gained weight evenly throughout their bodies.

The researchers note that physicians should know that the location of fat is important. Greater attention should be given to the circumference of a patient's waistline, not just their body mass index (BMI). The study was funded by the National Institutes of Health.