The B Vitamins Reviewed - Part 2

Tweet

Pantothenic acid forms a large part of the coenzyme A molecule. Coenzyme A is essential for the chemical reactions that generate energy from carbohydrates, fats, and proteins. Pantothenic acid, in the form of coenzyme A, is needed for the synthesis of cholesterol and the synthesis of steroid hormones such as melatonin. Coenzyme

A is also needed for the synthesis of acetylcholine, a neurotransmitter. Heme, a component of hemoglobin, cannot be synthesized without coenzyme A. In addition, the liver requires coenzyme A in order to metabolize a number of drugs and toxins.

Pantothenic acid deficiency is very rare and seen only in cases of severe mal- nutrition. Pantothenic acid is found in many common foods and average diets arethought to have an adequate amount of it. Pantothenic acid is also made by the normal bacteria that live in the colon.

Healthy sources of pantothenic acid include whole grains, nuts and seeds, nutritional yeast, sweet potatoes, legumes, mushrooms, tomatoes, and broccoli.

The adequate daily intake is 5 mg.

The terms folate and folic acid are both used for this water-soluble B vitamin. Folic acid is the form normally used in vitamin supplements and in fortifying food. Folic acid is readily converted to folate in the body. Folic acid is rarely found in food or in the human body. On the other hand, folates are found in food in many naturally-occurring forms. Folates are the metabolically active forms in the human body. RDA: adults, 400 mcg; pregnant women, 600 mcg.

Vitamin B6 is unusual as a B vitamin in that it is so extensively stored  in muscle tissue. Glucose is stored as glycogen in muscle tissue to provide energy on-site and when it is first needed. Vitamin B6 is depleted by alcohol drinking. Alcohol is broken down to acetaldehyde in the body. Elevated homocysteine in the blood is an indicator that there is increased risk of cardiovascular disease. Vitamin B6 is needed to remove homocysteine from the blood by converting homocysteine to cysteine. RDA for men is 1.7 mg and for women 1.5 mg.

Vitamin B12 is unusual for a vitamin in that it contains cobalt. The name, cobalamin, derives from “cobal” from the word cobalt plus “amin” from the word vitamin (cobalamin). One function of vitamin B12 is to convert homocysteine to methionine. One of the active forms of cobalamin, methylcobalamin, converts homocysteine using an enzyme that also requires folate. The other active form of vitamin B12, deoxyadenosyl cobalamin, has an important role in the production of energy from proteins and fats.

Vitamin B12 is one of the nutrients required for the synthesis of hemoglobin, the oxygen-carrying pigment in blood. Vitamin B12 is needed for DNA synthesis in the rapidly dividing cells of the bone marrow. Lack of vitamin B12 or folate can lead to the production of large, immature, hemoglobin-poor red blood cells. This can result in pernicious anemia. RDA: men and women, 2.4 mcg.