Food Nutrients - Vitamins - Vitamin B

This is actually a group of vitamins comprising 8:

• Vitamin B1 (Thiamine)
• Vitamin B2 (Riboflavin)
• Vitamin B3 (Niacin)
• Vitamin B6 (Pyridoxine)
• Pantothenic Acid 
• Biotin
• Folic Acid
• Vitamin B12

What does it do? Vitamin B1 is needed to process carbohydrates, fat, and protein. Every cell of the body requires vitamin B1 to form ATP—the fuel the body runs on. Nerve cells require vitamin B1 in order to function normally.
Where is it found? Wheat germ, whole wheat, peas, beans, so-called enriched flour, fish, peanuts, and meat are all good sources of vitamin B1.
Who is likely to be deficient? Deficiency is most commonly found in alcoholics, people with malabsorption conditions, and those eating a very poor diet.
How much is usually taken? While ideal levels are somewhat uncertain, one study reports that the healthiest people eat more than 9 mg per day. The amount found in many multivitamin supplements (20–25 mg) is more than adequate.
Can i take too much? Vitamin B1 is nontoxic, even in very high amounts.
Are there any interactions with other nutrients? Vitamin B1 works hand in hand with vitamin B2 and B3. Therefore, nutritionists usually suggest that vitamin B1 be taken as part of a B-complex vitamin or other multivitamin supplement.

Vitamin B2 (Riboflavin):

What does it do? Vitamin B2 is needed to process amino acids and fats, activate vitamin B6 and folic acid, and help convert carbohydrates into ATP, the fuel the body runs on. Under some circumstances, vitamin B2 can act as an antioxidant.
Where is it found? Dairy, eggs, and meat contain significant amounts of vitamin B2. Leafy green vegetables and whole and so-called enriched grains contain some vitamin B2.
Who is likely to be deficient? Vitamin B2 deficiency can occur in alcoholics. Also, a deficiency may be more likely in people with cataracts or sickle cell anemia.
How much is usually taken? Ideal levels remain unknown, but the recommended daily allowance might be higher than necessary. Vegans (vegetarians who eat no dairy or eggs) generally consume less than 1 mg per day of vitamin B2, yet they do not usually show any signs of deficiency. The amounts found in many multivitamin supplements (20–25 mg) are more than adequate.
Are there any side effects or interactions? At supplemental and dietary levels, vitamin B2 is nontoxic.
Vitamin B2 works with vitamins B1, B3, and B6; consequently

Vitamin B3:

What does it do? The body uses vitamin B3 in the process of releasing energy from carbohydrates. It’s needed to form fat from carbohydrates and to process alcohol. The niacin form of vitamin B3 also regulates cholesterol, though niacinamide does not.
Vitamin B3 comes in two basic forms—niacin (also called nicotinic acid) and niacinamide (also called nicotinamide). A variation on niacin, called inositol hexaniacinate, is also available in supplements. Because it has not been linked with any of the usual niacin toxicity in scientific research, inositol hexaniacinate is sometimes prescribed by European doctors for those who need high doses of niacin.
Where is it found? The best food sources of vitamin B3 are peanuts, brewer’s yeast, fish, and meat. Some vitamin B3 is also found in whole grains.
Who is likely to be deficient? Pellagra, the disease caused by a vitamin B3 deficiency, is rare in Western societies. Symptoms include loss of appetite, skin rash, diarrhea, mental changes, beefy tongue, and digestive and emotional disturbance.
How much is usually taken? In part because it is added to white flour, most people probably get enough vitamin B3 from their diets; however, 10–25 mg of the vitamin can be taken as part of a B-complex or multivitamin supplement.
Are there any side effects or interactions? Niacinamide is almost always safe to take, although rare liver problems have occurred at doses in excess of 1,000 mg per day. Niacin, in amounts as low as 50–100 mg, may cause flushing, headache, and stomachache in some people.
Vitamin B3 works with vitamin B1 and B2 to release energy from carbohydrates. Therefore, these vitamins are often taken together in a B-complex or multiple vitamin supplement (although most B3 research uses niacin or niacinamide by itself).

What does it do? Vitamin B6 is the master vitamin in the processing of amino acids—the building blocks of all proteins and some hormones. Vitamin B6 helps to make and take apart many amino acids and is also needed to make serotonin, melatonin, and dopamine. Vitamin B6 also aids in the formation of several neurotransmitters and is therefore an essential nutrient in the regulation of mental processes and possibly mood. To some extent, vitamin B6 lowers homocysteine levels—a substance that has been linked to heart disease, stroke, osteoporosis, and Alzheimer’s disease.
Where is it found? Potatoes, bananas, raisin bran cereal, lentils, liver, turkey, and tuna are all good sources of vitamin B6.
Who is likely to be deficient? Vitamin B6 deficiencies, although very rare, cause impaired immunity, skin lesions, and mental confusion. A marginal deficiency sometimes occurs in alcoholics, patients with kidney failure, and women using oral contraceptives.
How much is usually taken? The most common supplemental intake is 10–25 mg per day; however, higher amounts (200–500 mg per day) may be recommended for certain conditions.
Are there any side effects or interactions? Although side effects from vitamin B6 supplements are rare, at very high levels (200 mg or more per day) this vitamin can eventually damage sensory nerves, leading to numbness in the hands and feet as well as difficulty walking. Vitamin B6 supplementation should be stopped if any of these symptoms begin to develop.
Pregnant and lactating women should not take more than 100 mg of vitamin B6.

What does it do? Pantothenic acid, sometimes called vitamin B5, is involved in the Kreb’s cycle of energy production and is needed to make the neurotransmitter acetylcholine. It is also essential in producing, transporting, and releasing energy from fats.
Where is it found? Liver, yeast, and salmon have high levels of pantothenic acid, but most other foods, including vegetables, dairy, eggs, grains, and meat also provide some pantothenic acid.
Who is likely to be deficient? Pantothenic acid deficiencies may occur in people with alcoholism but are generally believed to be rare.
How much is usually taken? Most people do not need to supplement with pantothenic acid. However, the 10–25 mg found in many multivitamin supplements might improve pantothenic acid status, as so-called primitive human diets provided greater amounts of this nutrient than is found in modern diets. Most cholesterol researchers using pantethine have given people 300 mg three times per day (total 900 mg).
Are there any side effects or interactions? Toxicity has not been reported at supplemental doses. Very large amounts of pantothenic acid (several grams per day) can cause diarrhea.
Pantothenic acid works together with vitamins B1, B2, and B3 to help make ATP—the fuel bodies run on.

What does it do? Biotin, a water-soluble B vitamin, acts as a coenzyme during the metabolism of protein, fats, and carbohydrates.
Where is it found? Good dietary sources of biotin include organ meats, oatmeal, egg yolk, soy, mushrooms, bananas, peanuts, and brewer’s yeast. Bacteria in the intestine produce significant amounts of biotin, which is probably available for absorption and use by the body.
Who is likely to be deficient? A dietary deficiency of biotin, however, is quite uncommon, even in those consuming a diet low in this B vitamin. Nonetheless, if someone eats large quantities of raw egg whites, a biotin deficiency can develop, because a protein in the raw egg white inhibits the absorption of biotin.
How much is usually taken? Researchers have estimated that 30 mcg per day appears to be an adequate intake for adults. Typically, consumption from a Western diet has been estimated to be 30–70 mcg per day. Larger amounts of biotin (8–16 mg per day) may be supportive for diabetics by lowering blood glucose levels and preventing diabetic neuropathy.Biotin in the amount of 2.5 mg per day strengthened the fingernails of two-thirds of the individuals with brittle nails, according to one clinical trial.
Are there any side effects or interactions? Excess intake of biotin is excreted in the urine; no toxicity symptoms have been reported.

Folic Acid:

What is it?
Folic acid is a water-soluble B vitamin that is also known as PGA (pteroylglutamic acid). The precise term for folic acid from food sources is folate. Folacin is another term that is often used to refer to folic acid.
What does it do?
Folic acid plays an important role in cell division and growth by acting as a co-enzyme that transports carbon from one compound to another during amino acid metabolism and nucleic acid synthesis. By preventing damage to cellular DNA, folic acid may reduce the risk of colon polyps, colorectal cancer and cervical cancer. During pregnancy, folic acid can be vital to healthy fetal growth.
Where do you get it?
Folic acid is found in many types of foods, particularly:

• liver
• yeast
• green leafy vegetables
• legumes
• orange juice
• oranges
• cereals
• breads
• wheat germ

The following chart lists some good sources of folic acid.

Because folic acid is not a very stable vitamin, about half the amount that comes from food is easily lost during cooking, processing, meal preparation and storage. To preserve it, use quick-cook methods (such as steaming in very little water), avoid overcooking vegetables, and eat raw fruits and vegetables frequently.
How much do we need?
If your diet includes five to nine servings of fresh fruits and vegetables and at least six servings of breads and cereals, you are probably getting enough folate to avoid a deficiency of folic acid. Nevertheless, most experts agree that folic acid supplements in the amount of 400 micrograms are beneficial. If you are likely to become pregnant or are a strict dieter, you should take a multivitamin with 400 micrograms of folic acid daily or eat cereals rich in folate.
People with folic-acid deficiencies risk adverse effects that include:

• impaired cell division
• adverse effect on growth in rapidly growing tissues
• clinical depression, especially melancholia, as well as less responsiveness to anti-depressants such as fluoxetine (Prozac)

Is it safe?
Generally, yes; there has been no upper limit established for the safe consumption of folic acid.

What is it?
Vitamin B12 is a water-soluble vitamin which is linked up with small peptides, or protein-like compounds, when it occurs in foods. When food gets to the stomach, the B12 and peptides are split by enzymes, and the B12 joins up with a special protein called intrinsic factor (IF) that is manufactured in the stomach. Vitamin B12 from food cannot get into the body unless it is hooked up to IF. Pernicious anemia results when the body does not make enough IF.
What does it do?
Vitamin B12 is needed to:

• produce normal red blood cells
• prevent megaloblastic anemia
• maintain myelin coating in the spinal cord, peripheral nerves and optic nerve
• synthesize RNA and DNA
• promote normal growth in children
• use fat and protein from foods effectively
• help slow the progression from HIV-positive status to AIDS
• prevent homocysteine accumulation, a risk factor in heart disease

Where do you get it?
Vitamin B12 is found in:

• beef, poultry, fish and dairy products
• fortified cereals, fruit juice, soy and bread products
• organ meats, such as liver and kidney
• egg yolks
• crab, oyster, salmon and herring

Fruits and vegetables contain no vitamin B12. Anything that grows in soil does not contain B12. Bacteria, fungi and algae can produce it, but plants cannot. Animals cannot produce vitamin B12 either; we get it from animal sources where it was already produced by bacterial synthesis. Our own small intestines have bacteria that make vitamin B12, but it is not absorbed.
How much do we need?
The Recommended Daily Allowance, or RDA, is 2.4 micrograms a day. The average adult diet in the U.S. provides about four to eight micrograms a day.
Certain groups are especially at risk for vitamin B12 deficiency.

• Some people over age 50 make less gastric acid and pepsin in their stomachs and therefore do not absorb enough vitamin B12 from food. This is called atrophic gastritis.
• Older people have an overgrowth of bacteria in their stomachs. The bacteria that are usually killed by stomach acid compete for the vitamin B12 that is available and take it for their own use.
• The elderly and strict vegetarians should eat fortified cereals and soy foods, or take a supplement, to get enough vitamin B12. If you are in either of these categories, be careful not to rely on label amounts of vitamin B12 in foods such as tempeh; this number represents not only vitamin B12, but also some analogs of it which are not absorbed.

Is it safe?
Up to levels of about 100 micrograms, vitamin B12 seems to be safe when taken orally. It is only beneficial in larger amounts for people with deficiencies.