Niacin

Also known as Vitamin B3

Vitamin B3

The B vitamins niacin (nicotinic acid) and niacinamide (nicotinamide) are commonly known as preventives of pellagra , which in 1912 was shown by American medical researcher Joseph Goldberger to result from a dietary deficiency. Niacin was first synthesized in 1867. The amino acid tryptophan is the precursor of niacin. Niacin and niacinamide function in the biochemistry of humans and other organisms as components of the two coenzymes nicotinamide adenine dinucleotide (NAD) and nicotinamide adenine dinucleotide phosphate (NADP); these operate in many enzyme-catalyzed oxidation and reduction reactions. The deficiency state in humans causes skin disease, diarrhea, dementia, and ultimately death. The deficiency state in dogs analogous to pellagra in humans is called blacktongue disease. Lean meats, peanuts and other legumes, and whole-grain or enriched bread and cereal products are among the best sources of niacin. The recommended daily dietary allowance for adults is 16 to 19 mg niacin equivalents (60 mg of dietary tryptophan to 1 mg of niacin) for men and 13 to 14 mg for women.

• Vasodilator (dilates blood vessels)
• Carbohydrate metabolism (converts food to energy)
• Cellular metabolism
• Tissue respiration
• Contituent of two coenzymes involved in oxidation-reduction reactions
• Coenzyme of electron transfer system
• Dehydrogenase reactions
• Oxidation to product ATP (NAD+)
• Biosynthesis of fatty acids, steroids, etc. (NADP+)
• Healthy skin
• Healthy nervous system

Deficiency symptoms:

• Pellagra
• Skin and gastrointestinal lesions
• Diarrhea
• Scaly dermatitis
• Stomatitis
• Skin rash
• Nervous disorders
• Mental disorders
• Dementia
• Memory loss
• Irritability
• Insomnia
• Weakness

What is Vitamin B3?

Niacin is part of a group of vitamins called B complex. There are eight B vitamins all together and they were at one time thought to be just one vitamin.

Research has shown that they are indeed all slightly different in structure.

The other seven B vitamins that make up B Complex are:

• B12
• Folic acid
• Riboflavin
• Biotin
• Pyridoxine
• Pantothenic acid
• Thiamine

They share similar characteristics; they are all water-soluble, they are all essential in enabling the body to use energy from food and they are all vital for the production of normal tissue.

Niacin is a white powder that is water-soluble and is the toughest of all the B vitamins making it more resistant to destruction than the others. Vitamin B3 or niacin (as it is called), comes in two basic forms: one is called nicotinic acid and the other is called nicotinamide (nicotinamide is also called niacinamide).

They both perform pretty much the same functions but it is nicotinic acid that has an ability that nicotinamide/niacinamide doesn't; nicotinic acid has the ability to lower cholesterol levels although it does produce some side-effects that are not found with nicotinamide/niacinamide. Those who need high dosages of niacin are often prescribed inositil hexaniacinate.

Why is it needed?

Needed to maintain a healthy skin, gastrointestinal tract and a healthy nervous system.

It is used by the body in the process of releasing energy from carbohydrates.

It is needed to form fat from carbohydrates and break down alcohol, it is involved in over 200 enzymatic reactions in the body.

Where is it found?

Peanuts, brewer's yeast, and meat contain the most niacin. A small amount of this vitamin can be found in whole grains too.

What happens if you are deficient?

A lack of this vitamin can affect every cell in the body. It is carried in the blood and found in all the tissues with the greatest concentrations found in the liver, kidneys, heart, brain and muscle.

Pellagra is a disease caused by a deficiency in both niacin and tryptophan with symptoms including dermatitis, dementia, loss of appetite, beefy tongue, emotional problems, sun-exposed skin becomes very dark.

Generalised weakness and fatigue are also symptoms of deficiency.

What conditions has it been used to treat?

Primary:

• Depression - used in conjunction with the amino acid tryptophan. It is reported to enhance the effect of tryptophan and maintains adequate levels of the neurotransmitter, serotonin.
• Alcohol withdrawal (niacinamide)
• High cholesterol and high triglycerides - both known to be involved with development of coronary artery disease. Nicotinic acid is used, yet the side effects when taking large doses do not always make it a popular choice with patients. (Refer to side-effects and contraindications)

Secondary:

• Cataracts (niacinamide)
• Diabetes (niacinamide)
• Painful menstruation
• Raynaud's disease
• Osteoarthritis
• Acne

How much is normally taken?

The RDA is 19 mg per day and most people get this amount from their diets. Those who supplement with B-Complex vitamins or multivitamins usually take in 25 mg of the vitamin which is more than enough.

It can have an adverse effect on the liver at doses in excess of 1,000 mg per day.

Are there any contraindications or side effects?

Flushing of the skin and intense itching are experienced by those who are take hundreds of milligrams and those who take doses in the thousands of milligrams range run the risk of liver damage.

Jaundice is usually the first sign with yellowing of the skin and eyes.

Other symptoms include headache, nausea, dizziness, vomiting, decreased blood pressure and diarrhoea.

All these side-effects are reversed if the dose is reduced.

Taken within the RDA there appear to be no side-effects.