Niacin Plus Exercise: A Heart-Healthy Combo?

Healthnotes Newswire (September 18, 2008)—Niacin and aerobic exercise can each separately help to lower blood fats called triglycerides. A study in the American Journal of Clinical Nutrition recently explored how these therapies might work together to promote heart health in people with the metabolic syndrome.

The metabolic syndrome is a group of risk factors for cardiovascular disease and type 2 diabetes, including abdominal obesity (tummy fat), insulin resistance (poor ability of the body to respond to fluctuations in blood sugar), low HDL (“good”) cholesterol, high blood pressure, and high triglycerides. When a person has three or more of these factors, they are said to have the metabolic syndrome, which affects an estimated 50 million Americans.

A two-pronged approach to treating the metabolic syndrome

The new study investigated the combined effects of niacin and aerobic exercise in 15 men with the metabolic syndrome. The study consisted of three parts:

• During the first, the men ate a high-fat meal only (control), containing 100 grams of fat;

• in the second part, the men exercised for about 50 minutes, one hour before a high-fat meal;

• in the third part, they took extended-release niacin in increasing dosages for six weeks (up to 1,500 mg per day) and then exercised for 50 minutes, one hour before a high-fat meal.

Blood levels of triglycerides and insulin were measured to assess the response to these therapies.

Compared with the control, triglyceride levels were 32% lower after the high-fat meal that was preceded by exercise. This effect lasted for up to six hours. While niacin lowered fasting triglyceride levels by 37%, niacin plus exercise did not decrease triglyceride levels immediately following the high-fat meal, suggesting that niacin canceled out the positive effect of exercise on after-meal triglyceride levels.

“While these results would appear to promote the use of one intervention over the other, it is important to note that a number of recent investigations provide evidence that niacin has important direct vascular anti-inflammatory properties which have not been observed with exercise alone,” said Dr. Eric Plaisance, the study’s lead author. “I would recommend a combination of exercise and niacin for patients with the metabolic syndrome; not only to reduce fasting and postprandial triglycerides, but also to directly reduce the vascular inflammatory cascade that is so prevalent in this population.”

A potential drawback to niacin therapy is that it can decrease insulin sensitivity; this effect was not seen when niacin was combined with exercise, suggesting that exercise can help offset the negative effects of niacin on blood sugar.

(Am J Clin Nutr 2008;88:30–7)