Vitamins are a group of substances that are needed for normal cell function, growth, and development. There are 13 essential vitamins:

• Vitamin A (retinol, retinal, 4 carotenoids)
• Vitamin C (ascorbic acid)
• Vitamin D (D3 - Cholecalciferol, D2 - Ergocalciferol)
• Vitamin E (tocopherols, tocotrienols)
• Vitamin K (phylloquinone, menaquinones)
• Vitamin B1 (thiamine)
• Vitamin B2 (riboflavin)
• Vitamin B3 (niacin)
• Vitamin B5 (pantothenic acid)
• Vitamin B6 (pyridoxine, pyridoxal, pyridoxamine)
• Vitamin B7 (biotin)
• Vitamin B9 (folic acid)
• Vitamin B12 (cyanocobalamin)

Fat-soluble vitamins are stored in the body's fatty tissue: vitamins A, D, E, K. 

Water-soluble vitamins - the body must use almost all water-soluble vitamins right away - vitamins B1, B2, B3, B5, B6, B7, B9 and C.
Vitamin B12 is the only water-soluble vitamin that can be stored in the liver for many years.

Vitamin B3 (Niacin or nicotinic acid) raises the levels of high-density lipoprotein cholesterol (HDL) by about 30% to 35%. Niacin was associated with a significant reduction in cardiovascular events and possible small but non-significant decreases in coronary and cardiovascular mortality.

Vitamin B3, Niacin, nicotinic acid, helps to convert food into energy and is essential for healthy skin, blood cells, brain, and nervous system. It is one of 8 B vitamins. It is water-soluble, which means it is not stored in the body. It has 2 other forms, niacinamide (nicotinamide) and inositol hexanicotinate, which have different effects. 

Niacin occurs naturally in food and can also be made by your body from the amino acid tryptophan, with the help of B6. 

It is rare for anyone in the developed world to have a Vitamin B3 deficiency; alcoholism is the main cause of it in the US.

Recommended daily amount: 14 - 16 mg.

Example sources: whole grains, mushrooms, peanuts and other legumes. 

Fruits (100 g) : 

1. Peaches or Apricots, dried - Niacin: 4 mg 
2. Avocados, raw or Dates, medjool  - Niacin: 2 mg 

Seeds (100 g):

1. Rice bran, crude - Niacin: 34 mg 
2. Sesame flour - Niacin: 13 mg 
3. Sunflower seed kernels, dried - Niacin: 8 mg