Niacin

Niacin

What is it?

• Niacin (Vitamin B3) is a water-soluble vitamin. It plays a role in the break-down and metabolism of proteins, fatty acids, and carbohydrates.

How does it work in the body?

• Niacin is essential in the conversion of carbohydrates to glucose. It also aids in the production of sex and stress hormones.

What is it used for?

• Niacin can be used to lower LDL and triglycerides. When supplementing niacin, research has shown that those with heart disease may have slowed progression of atherosclerosis and lower risk for heart attack or stroke. Niacin may raise blood sugar but have positive effects on the amount of fat in the blood; therefore, more research is needed on niacin supplementation for diabetics. Niacin is associated with lower risk of cataracts and Alzheimer's disease. Although more research is needed, applying topical niacin can possibly improve skin conditions.

Dosage:

• RDA: 16 mg/day in adult males 14 years and older. 14 mg/day for females 14 years and older.

• Multiple resources show variable doses between 1 and 3 g/day can be effective on lowering lipids for adults.

• For high levels of LDL, 3000 mg/day of niacin supplementation has shown effectiveness.

• With regular release niacin, it is recommended to start at 350 mg once daily with dinner and increase every week until therapeutic dose is reached. For extended release, it is recommended to start at 500 mg x 4 weeks (taken at night time) and adjust by 500 mg or less every 4 weeks to a max of 2000 mg/day.

• Pellagra treatment for pediatrics: regular release 50-300 mg/day for 3-4 weeks.

• Excessive intake is excreted by the kidneys, no toxicity levels have been found.

Evidence for or against its different uses:

• Skin: A randomized, double blind control trial studied the effects of topical niacin on facial photoaging. The 50 adults included in this study, applied 5% niacinamide twice daily for 12 weeks. At the end of 12 weeks, there were significant improvements in facial appearance.

• CVD: Research has shown that niacin is one of the most useful agents to help manage dyslipidemia. The coronary drug project demonstrated that niacin supplementation had similar effects to statins for reduction in cardiovascular disease and mortality. In a 3-year trial, treatment of coronary disease with simvastatin and niacin showed clinical and measurable benefits.

• A review and meta-analysis of randomized controlled trials concluded that niacin improves endothelial function.

• DM: A randomized control trial looked at the effect of niacin on lipid profiles and glycemic control in individuals with diabetes. Niacin usage showed significant improvements in HDL-C and LDL-C. Glucose levels were modestly increased. This study concluded that niacin can be safely used for patients with diabetes.

Safety concerns/side effects:

• Niacin supplementation can lead to flushing, pruritus, paresthesias, and nausea.

• Niacin supplementation is contraindicated in adults with significant liver dysfunction/disease, stomach ulcers, or kidney disease. Therefore, caution should be taken when supplementing niacin in those with excessive alcohol intake.

Interactions with medications:

• Niacin should not be taken with antibiotic tetracycline as it interferes with the absorption of the drug.

• Niacin may enhance some anticoagulants, resulting in a greater risk of bleeding.

• Niacin can enhance blood pressure medications, resulting in lower blood pressure levels.

• Diabetics taking niacin should monitor blood sugar levels as it can be increased.

• Aspirin can be used as an agent to decrease niacin flush.

• Alcohol can increase side effects when taken with niacin (flushing, hepatotoxicity).

• Bile acid sequestrants should be taken separately from niacin as they may decrease absorption.

• Niacin should be avoided with use of simvastatin due to risk of rhabdomyolysis.