Blood clots cause heart attacks and strokes. About every 40 seconds someone in the United States suffers a stroke, and every 25 seconds someone suffers a cardiac event, according to the 2011 heart disease and stroke statistics published by "Circulation." Factors that increase your risk for suffering a stroke include high blood pressure, high cholesterol, obesity and smoking.
Blood Clots
Ischemic strokes, caused by blood clots, account for 87 percent of all strokes, according to the American Heart Association. Niacin may improve two conditions that contribute to blood clots: high cholesterol and atherosclerosis, more commonly referred to as hardening of the arteries. But the National Institutes of Health halted a niacin study in May 2011 because initial results showed no improvement in heart attack rates and a higher incidence of strokes among niacin users.
Niacin Sources and Uses
Niacin occurs naturally in a number of foods, including tuna, beef and nuts. Tryptophan, found in foods such as poultry and eggs, also converts to niacin in your bloodstream. A healthy diet includes about 14 mg to 16 mg of niacin daily -- enough to help you metabolize carbohydrates, fats and protein in your diet and promote eye, skin and liver health. You can purchase over-the-counter niacin supplements in strengths of up to about 250 mg. Doctors may prescribe niacin in much higher doses -- 500 mg to 2,000 mg -- to improve cholesterol and reduce hardening of the arteries.
Niacin and Cholesterol
Niacin taken in high doses can help lower your low-density lipoprotein -- LDL or "bad" cholesterol -- and elevate your high-density lipoprotein -- HDL or "good" cholesterol. Niacin can also help lower triglycerides. LDL cholesterol and triglycerides can clog your arteries, increasing your risk of blood clots. HDL cholesterol pulls triglycerides and LDL cholesterol out of your bloodstream. Improved cholesterol numbers protect you against heart attacks and strokes, but the NIH study casts doubt on the protective effects of niacin.
Risks
Participants in the NIH study either took statins, a cholesterol-lowering drug, alone or in combination with 2,000 mg of niacin. Niacin proved more effective in lowering triglycerides and raising HDL cholesterol than statins alone. But this improvement did not prove beneficial. Participants in the study who took both niacin and statins suffered as many heart attacks -- and more strokes -- as participants who took only statins. Other side effects of taking niacin in high doses include stomach ulcers and liver disease. Some persons who take niacin also experience skin flushing, a reddening and burning sensation in their face and chest.
References
- "Circulation"; Heart Disease and Stroke Statistics: 2011 Update; Véronique L. Roger, M.D. etal; December 2010
- American Heart Association; About Stroke: Types of Stroke
- CBC News; Niacin Trial For Heart Disease Stopped Early; May 27, 2011
- National Institutes of Health: NIH Halts Clinical Trial on Combination Cholesterol Treatment; May 26, 2011
- University of Maryland Medical Center: Vitamin B3 (Niacin)
- Medline Plus: Niacin and Niacinamide (Vitamin B3)
