Q. Can you get enough vitamin b3 from food and diet?
A.Most niacin, or vitamin B3 is found in many foods, and your body is able to manufacture its own niacin from tryptophan, an amino acid in protein, so most people are not vitamin b3 deficient, unless they have an extremely poor diet. However, those who abuse alcohol or are vegetarian or vegan may want to take a niacin supplement—alcohol inhibits vitamin B3 absorption, and diets that lack protein are probably niacin deficient.

Q.What are the food sources of Niacin?
A.Niacin (also known as vitamin B3) is found in:
Dairy products, Eggs, Enriched breads and cereals, Fish, Lean meats, Legumes, Nuts, Poultry.

Q.What is niacin?
A. Niacin (nicotinic acid) is a B vitamin that's used by your body to turn carbohydrates into energy. Niacin also helps keep your nervous system, digestive system, skin, hair and eyes healthy. That's why niacin is often a part of a daily multivitamin, though most people get enough niacin from the food they eat. You may see niacin labeled in different ways. As part of a multivitamin or supplement, it's often just referred to as niacin. When it's used as a treatment to increase your HDL cholesterol or correct a niacin deficiency, it's sold in higher doses that are prescribed by your doctor. It's not possible to get enough niacin from the food you eat to increase your HDL cholesterol. 

Q.What are the dietary sources for Niacin?
A.The best food sources of vitamin B3 are found in beets, brewer's yeast, beef liver, beef kidney, fish, salmon, swordfish, tuna, sunflower seeds, and 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.

Q.What are the possible interactions of niacin with other medications?
A.If you are currently taking any of the following medications, you should not use niacin without first talking to your health care provider.
Antibiotics, Tetracycline -- Niacin should not be taken at the same time as the antibiotic tetracycline because it interferes with the absorption and effectiveness of this medication. All vitamin B complex supplements act in this way and should be taken at different times from tetracycline.
Aspirin -- Taking aspirin before taking niacin may reduce flushing from niacin, but take it only under your doctor's supervision.
Anti-seizure Medications -- Phenytoin (Dilantin) and valproic acid (Depakote) may cause niacin deficiency in some people. Taking niacin with carbamazepine (Tegretol) or mysoline (Primidone) may increase levels of these medications in the body.
Anticoagulants (blood thinners) -- Niacin may make the effects of these medications stronger, increasing the risk of bleeding.
Blood Pressure Medications, Alpha-blockers -- Niacin can make the effects of medications taken to lower blood pressure stronger, leading to the risk of low blood pressure.
Cholesterol-lowering Medications -- Niacin binds the cholesterol lowering medications known as bile-acid sequestrants and may make them less effective. For this reason, niacin and these medications should be taken at different times of the day. Bile-acid sequestrants include colestipol (Colestid), colesevelam (Welchol), and cholestyramine (Questran).