A clinical trial of oat bran and niacin in the treatment of hyperlipidemia.
BACKGROUND
Previous studies have demonstrated the lipid-lowering potential of wax-matrix controlled-release forms of nicotinic acid, but questions have been raised about the risks associated with long-term use. This report describes a 38-week trial that was designed as a follow-up to a shorter 16-week clinical trial of wax-matrix controlled-release niacin. The present study also tested the hypothesis that niacin (1500 mg/d) and oat bran (56 g/d [2 oz/day]) may have a synergistic effect on improving serum lipid levels.


METHODS
Ninety-eight subjects began the following protocol: oat bran alone (6 weeks), oat bran plus niacin (6 weeks), and niacin alone (32 weeks). Blood lipids, blood chemistries, nutritional variables, and side-effect profiles were monitored throughout the study. Sixty-nine (70%) subjects completed the trial taking the full dose of niacin (1500 mg/d); 8 subjects completed the trial taking a reduced dose of niacin (average 906 mg/d); 11 discontinued taking any niacin because of either intolerable side effects (n = 7) or liver enzyme abnormalities (n = 4).


RESULTS
Generally, oat bran-niacin synergism was not found. Only 10% of subjects who completed the study showed greater than expected lipid improvement on combination therapy. From baseline to the end of the final phase, significant reductions (P less than .05) occurred for total cholesterol (-10%) and low-density lipoprotein cholesterol (-16%). High-density lipoprotein cholesterol rose significantly at the end of the oat bran plus niacin phase, but returned to near baseline by the end of the study. The liver enzymes alkaline phosphatase, lactate dehydrogenase, and aspartate aminotransferase all showed a tendency to rise throughout the study.


CONCLUSIONS
The results of this 38-week trial suggest that the relatively inexpensive wax-matrix form of niacin is effective and reasonably well tolerated. Approximately 8% of subjects were unable to continue taking niacin because of side effects, and 4% discontinued taking niacin because of liver enzyme elevations. A small group of subjects (10%) experienced greater than expected lipid improvements (synergism) on combined oat-bran and niacin therapy. Liver function monitoring with long-term use of niacin is warranted.
Keenan
J M
JM
Department of Family Practice and Community Health, University of Minnesota, MN.
Wenz
J B
JB
Ripsin
C M
CM
Huang
Z
Z
McCaffrey
D J
DJ
D000328:Adult; D000368:Aged; D003692:Delayed-Action Preparations; D004359:Drug Therapy, Combination; D002523:Edible Grain; D005260:Female; D006801:Humans; D006949:Hyperlipidemias / Q000097:blood / Q000628:therapy*; D008074:Lipoproteins / Q000097:blood; D008297:Male; D008875:Middle Aged; D009525:Niacin / Q000008:administration & dosage* / Q000009:adverse effects
D003692:Delayed-Action Preparations; D008074:Lipoproteins; D009525:Niacin