-Atherosclerosis and heart disease
In one study, men with existing heart disease slowed down the progression of atherosclerosis by taking niacin along with colestipol. They experienced fewer heart attacks and deaths, as well.
people with heart disease and high cholesterol who took niacin along with simvastatin (Zocor) had a lower risk of having a first heart attack or stroke. Their risk of death was also lower. In another study, men who took niacin alone seemed to reduce the risk of having a second heart attack, although it did not reduce the risk of death.
-Diabetes
In type 1 diabetes, the body's immune system mistakenly attacks the cells in the pancreas that make insulin, eventually destroying them. Niacinamide may help protect those cells for a time. More research is needed.
Researchers have also looked at whether high-dose niacinamide might reduce the risk of type 1 diabetes in children at risk for the disease. One study found that it did. But another, larger study found it did not protect against developing type 1 diabetes. More research is needed.
The effect of niacin on type 2 diabetes is more complicated. People with type 2 diabetes often have high levels of fats and cholesterol in the blood. Niacin, often along with other medications, can lower those levels. However, niacin may also raise blood sugar levels, which is particularly dangerous for someone with diabetes. For that reason, if you have diabetes, you should take niacin only under the direction of your doctor, and you should be carefully monitored for high blood sugar.
-Osteoarthritis
One preliminary study suggested that niacinamide may improve arthritis symptoms, including increasing joint mobility and reducing the amount of non-steroidal anti-inflammatory drugs (NSAIDs) needed. More research is needed.
researchers are also studying the use of vitamin B3 in treating:
ADHD
Migraines
Dizziness
Depression
Motion sickness
Alcohol dependence
Dietary Sources
The best food sources of vitamin B3 are:
Beets
Brewer's yeast
Beef liver
Beef kidney
Fish
Salmon
Swordfish
Tuna
Sunflower seeds
Peanuts
Bread and cereals are usually fortified with niacin. In addition, foods that contain tryptophan, an amino acid the body coverts into niacin, include poultry, red meat, eggs, and dairy products.
Available Forms
Vitamin B3 is available in several different supplement forms:
Niacinamide
Niacin
Inositol hexaniacinate.
Niacin is available as a tablet or capsule in both regular and timed-release forms. The timed-release tablets and capsules may have fewer side effects than regular niacin. However, the timed-release versions are more likely to cause liver damage. Regardless of which form of niacin you are using, doctors recommend periodic liver function tests when using high doses (above 100 mg per day) of niacin.
How to Take It
Generally, high doses of niacin are used to control specific diseases. Such high doses must be prescribed by a doctor who will increase the amount of niacin slowly, over the course of 4 to 6 weeks. Take niacin with meals to avoid stomach irritation.
Daily recommendations for niacin in the diet of healthy individuals are:
Pediatric
Infants, birth to 6 months: 2 mg (adequate intake)
Infants, 7 months to 1 year: 4 mg (adequate intake)
Children, 1 to 3 years: 6 mg (RDA)
Children, 4 to 8 years: 8 mg (RDA)
Children, 9 to 13 years: 12 mg (RDA)
Boys, 14 to 18 years: 16 mg (RDA)
Girls, 14 to 18 years: 14 mg (RDA)
Adult
Men, 19 years and older: 16 mg (RDA)
Women, 19 years and older: 14 mg (RDA)
Pregnant women: 18 mg (RDA)
Breastfeeding women: 17 mg (RDA)
Precautions
Because of the potential for side effects and interactions with medications, you should take dietary supplements only under the supervision of a knowledgeable health care provider. Side effects may include diarrhea, headache, stomach discomfort, and bloating.
High doses (50 mg or more) of niacin can cause side effects. The most common side effect is called "niacin flush," which is a burning, tingling sensation in the face and chest, and red or flushed skin. Taking an aspirin 30 minutes prior to the niacin may help reduce this symptom.
At very high doses, used to lower cholesterol and treat other conditions, liver damage and stomach ulcers can occur. Your doctor will regularly check your liver function through a blood test.
People with a history of liver dise