Formula Medical Group
Apple Valley, CA

James Krider, MD

   any search words
   all search words

Vitamin B complex - Niacin, thiamine, riboflavin, B6, B12, folacin, and biotin

What is vitamin B complex?

Vitamin B complex refers to combinations of B vitamins. Specifically the vitamins included in B complex are: thiamine (B1, riboflavin (B2), niacin (nicotinamide or nicotinic acid), folacin (folic acid), vitamin B6 (pyridoxine), and vitamin B12. Biotin may also be included.

The B vitamins are all water soluble. The body can store enough to last months or even years, but ideally, they should be replenished on a daily basis.

Why are B vitamins important to nutrition?

Each of the B vitamins is essential to maintaining health, and each serves different functions. These include:

  • Niacin. This helps build body fat, enables body cells to take up oxygen and give off carbon dioxide, and assists in the burning of carbohydrates for energy. This vitamin also promotes healthy skin, nerves, and digestive organs
  • Thiamine. This is part of a coenzyme that promotes the body's breakdown and use of carbohydrates. Thiamine also is essential for DNA and RNA, which carry the genetic code. This vitamin also promotes appetite and normal function of the nervous system.
  • Biotin. This is produced by intestinal bacteria and helps make blood cells, maintain skin, and metabolize fatty acids and amino acids.
  • Riboflavin. This helps cells use oxygen, and it also promotes good vision and healthy skin.
  • Folacin. This promotes protein metabolism and red blood cell formation.

Good sources of B vitamins

  • Liver and other organic meats.
  • Meat, poultry, and fish.
  • Dairy products.
  • Vegetables and grains.
A varied diet provides all the B vitamins.

A varied diet provides all the B vitamins.

  • Vitamin B 6. This promotes fat and protein metabolism and helps transform the amino acid tryptophan into niacin.
  • Vitamin B 12. This helps make nucleic acids, assists in normal red cell development, and helps maintain nerve cells.

How much of the B vitamins do I need?

The recommended dietary allowance (RDA) for these vitamins for adults and children over 4 years old is:

  • Thiamine, 1.5 milligrams.
  • Riboflavin, 1.7 milligrams.
  • Niacin, 20 milligrams.
  • Folacin, 0.4 milligrams.
  • Vitamin B6, 2.0 milligrams.
  • Vitamin B12, 6 micrograms.
  • Biotin, not established, but no more than a few micrograms a day.

What happens if I don't get enough of the B vitamins?
Deficiency of one or another of the B vitamins can result in a variety of illnesses, depending upon which of the individual vitamins is lacking. These include:

  • Thiamine. Retarded
    growth; tissue wasting;
    mental confusion; depression; swelling of body tissues due to fluid retention. Severe deficiency can produce beriberi.
  • Riboflavin. Erosions on the corneas of the eyes and cracks around the mouth.
  • Niacin. Sores on the skin and in the gastrointestinal tract; loss of appetite; weakness; irritability; dizziness. A severe deficiency can produce the disease pellagra.
  • Folacin. Red tongue, diarrhea, fatigue, and weakness.
  • Biotin. Dry skin, anemia, elevated cholesterol.
  • Vitamin B6. Irritability, muscle twitches, skin problems around the eyes, kidney stones, anemia.
  • Vitamin B12. Tremors, loss of appetite, weight loss, burning tongue, fatigue, and nervous system symptoms. Severe deficiency causes pernicious anemia.

What happens if I get too much vitamin B?
You may not suffer any ill effects, since these vitamins are quickly washed out of the body. But overconsumption of niacin, in the form of nicotinic acid, can produce facial flushing, headache, and cramps.

Should I take vitamin B complex?
Probably not, since you are unlikely to need all of the B vitamins that one of these products contains. The people who are at high risk of depletion of several or more of these vitamins are alcoholics and people who are starving or eating only nutritionally poor food. They would be better advised to spend their money on food rather than vitamin pills. Supplements of folacin, but not the other B vitamins, are recommended for women who are pregnant or nursing. People with pernicious anemia will need lifelong vitamin B12 injections.

Advice about vitamin B complex

If you are eating a varied diet you do not need to take vitamin B complex. These pills often are promoted as antiess vitamins, but there is no evidence that they relieve stress.

Many vegetables and grains are high in B vitamins.
Many vegetables and grains are high in B vitamins.
This article was last reviewed December 20, 2005 by Dr. James Krider.
Reproduced in part with permission of Home Health Handbook.

Printer Friendly Page

Return to Nutrition