Vitamin B3 (Niacin)

Vitamin B3 is one of 8 B vitamins. It is also known as niacin (nicotinic acid) and has 2 other forms, niacinamide (nicotinamide) and inositol hexanicotinate, which have different effects from niacin.

All B vitamins help the body convert food (carbohydrates) into fuel (glucose), which the body uses to produce energy. These B vitamins, often referred to as B-complex vitamins, also help the body use fats and protein. B-complex vitamins are needed for a healthy liver, healthy skin, hair, and eyes, and to help the nervous system function properly. 

Niacin also helps the body make various sex and stress-related hormones in the adrenal glands and other parts of the body. Niacin helps improve circulation, and it has been shown to suppress inflammation. All the B vitamins are water-soluble, meaning that the body does not store them.

You can meet all of your body's needs for B3 through diet. It is rare for anyone in the developed world to have a B3 deficiency. In the U.S., alcoholism is the main cause of vitamin B3 deficiency. 

Symptoms of mild B3 deficiency include

~ Indigestion

~ Fatigue

~ Canker sores

~ Vomiting

~ Poor circulation

~ Depression

High cholesterol

Niacin, but not niacinamide, has been used since the 1950s to lower elevated LDL (bad) cholesterol and triglyceride (fat) levels in the blood. However, side effects can be unpleasant and even dangerous. High doses of niacin cause: 

~ Flushing of the skin
~ Stomach upset (which usually subsides within a few weeks)
~ Headache
~ Dizziness
~ Blurred vision
~ An increased risk of liver damage

A time-release form of niacin reduces flushing. But long-term use is associated with liver damage. In addition, niacin can interact with other cholesterol-lowering medicines. You should not take niacin at high doses without your doctor's supervision.

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.

In another study, 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.

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

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 disease, kidney disease, or stomach ulcers should not take niacin supplements. Those with diabetes or gallbladder disease should do so only under the close supervision of their doctors. 

Stop taking niacin or niacinamide at least 2 weeks before a scheduled surgery. 

Niacin and niacinamide may make allergies worse by increasing histamine. 

People with low blood pressure should not take niacin or niacinamide because they may cause a dangerous drop in blood pressure. DO NOT take niacin if you have a history of gout. 

People with coronary artery disease or unstable angina should not take niacin without their doctor's supervision, as large doses can raise the risk of heart rhythm problems. 

Taking any one of the B vitamins for a long period of time can result in an imbalance of other important B vitamins. For this reason, you may want to take a B-complex vitamin, which includes all the B vitamins.