How Does Body Fat Raise Heart Disease Risk?
Study Finds Inflammatory Proteins Produced by Fat Could Play a Role
March 29, 2005 -- Excess fat -- especially around the waist -- could prompt
If so, fat may not be idle. Instead, it might act like an unwelcome extra organ that pushes people toward heart disease, a leading killer of U.S. men and women.
"It is well known that obesity affects nearly one-third of adults in the U.S. and is closely linked with heart disease," says researcher Tongjian You, PhD, in a news release.
"While we don't fully understand the link between obesity and heart disease, our study suggests that inflammatory proteins produced by fat itself may play a role," says You, who works at Wake Forest University's medical school.
Just what is fat up to, and how does it work? The verdict isn't in yet. But here's what the latest study found.
Fat may produce inflammatory proteins and slash levels of inflammation-fighting proteins, says the study. That can set the stage for
a group of risk factors linked to higher risk of heart disease and diabetes.
Symptoms of metabolic syndrome include excess body fat (particularly around the waist), high blood pressure, high triglycerides (blood fats), low levels of HDL ("good") cholesterol, and increased levels of blood sugar. At least three of those symptoms are required for diagnosis.
The details of the fat-inflammation connection aren't clear yet. Meanwhile, the study suggests that there's more to fat than what scales and mirrors reveal.
The small study offers a snapshot of belly fat and inflammation. Participants were 20 obese or overweight, postmenopausal women aged 50-70. Much of their excess fat was in the waist and belly.
The researchers focused on several fat and blood-derived proteins that cause or curb inflammation.
Higher belly fat accompanied lower levels of the hormone leptin, which is thought to decrease appetite. The women also had lower levels of adiponectin, which fights inflammation.
Higher levels of the inflammatory proteins were linked to increased levels of blood sugar -- a sign of insulin resistance.
On the flip side, higher levels of the anti-inflammatory proteins went along with a better ability to handle blood sugar.
Trouble With Metabolic Syndrome
Eight women were diagnosed with metabolic syndrome. Their levels of adiponectin were 32% lower than the women without metabolic syndrome.
"This suggests that low production of adiponectin in subcutaneous fat is linked with an elevated risk of heart disease," says You in the news release.
The researchers say the findings amount to associations, not a smoking gun. They're hoping to learn if medications, exercise, and diet can help.
It's not clear yet if inflammatory proteins subside with weight loss, but getting in shape is universally recommended for better health. See a doctor first for tips on safe, effective diet and fitness plans.
The study is due to appear in the April issue of the American Journal of Physiology -- Endocrinology and Metabolism.