HDL, or "good" cholesterol, isn't as protective for people with type 2 diabetes as it is for healthier people, according to new research.
But the good news is that niacin, a B vitamin, can help restore HDL's benefit in diabetics.
High-density lipoprotein is considered the body's good cholesterol because it carries "bad" LDL cholesterol out of the arteries and back to the liver, where it is eliminated.
High HDL levels are thought to lower the risk of heart disease, perhaps becasue they increase the vessels' ability to expand and repair damage to the vessel lining.
But in people with diabetes, HDL may be less protective, suggests the research in this week's issue of Circulation.
Researchers at the University Hospital Zurich and the Medical School of Hannover in Germany compared the vessel-protecting action of HDL on 10 healthy adults and 33 patients with type 2 diabetes and metabolic syndrome (a condition that includes having low levels of HDL).
They found that HDL's ability to help blood vessels repair themselves and to dilate was "substantially impaired" in the diabetic patients compared with the healthy people.
The researchers then prescribed the diabetic patients either 1,500 milligrams of extended-release niacin a day, or a placebo pill. Niacin, a member of the family of B vitamins, has been shown to raise HDL cholesterol while also reducing LDL and triglyceride levels.
All of the diabetics were also taking statins to lower their bad cholesterol.
After three months on the medication, patients taking the niacin had increased HDL levels, and markedly improved protective functions of HDL in laboratory testing, as well as improved vascular function.
While the results were encouraging, the researchers say because of how small the study was, more research is needed to determine if niacin should be recommended for diabetic patients.
