B complex refers to the eight vitamers that constitute the B vitamin group. Vitamers are sub-types of vitamins that have similar and related functions, but different molecular structure. B vitamins all play important roles in cellular metabolism and energy production, but also contribute to digestion, immunity and red blood cell synthesis. In supplemental form, they can be taken individually or as a complete B complex. The daily requirements of the B vitamins vary dramatically, with women's levels being slightly higher than men's during pregnancy and lactation.
Vitamin B-1
Vitamin B-1, or thiamine, is needed for the break-down of complex sugars and amino acids. Dietary Reference Intake, or DRI, for women for all ages is 1.1 mg daily, although that increases to 1.4 mg if pregnant or lactating, as cited by the Institute of Medicine. Thiamine deficiency leads to beriberi, which causes mood disturbances, impaired senses and limb pain.
Vitamin B-2
Vitamin B-2, or riboflavin, is used in the metabolism of fats, ketone bodies, carbohydrates and proteins. The DRI for women of all ages is 1.1 mg daily, although that increases to 1.4 mg if pregnant and 1.6 mg if lactating. The DRI is the minimum daily amount of a nutrient to prevent deficiency symptoms in up to 98 percent of people, as cited in "Contemporary Nutrition."
Vitamin B-3
Vitamin B-3, or niacin, is needed for DNA repair and the production of sex-related steroid hormones. The DRI for women of all ages is 14 mg daily, but increases to 18 mg if pregnant and 17 mg if lactating. Too much niacin can lead to flushing, or vasodilation of the skin, which includes redness, itching and mild burning around the face and neck.
Vitamin B-5
Vitamin B-5, or pantothenic acid, is needed to synthesize coenzyme-A, proteins, carbohydrates and fats. It is considered the best vitamin for stress. The DRI for women of all ages is 5 mg daily, although that increases to 6 mg if pregnant and 7 mg if lactating. Deficiency is rare, but can cause facial acne and tingling in the limbs.
Vitamin B-6
Vitamin B-6, or pyridoxine, is required for amino acid metabolism and to release glucose from stored glycogen. B-6 is the main vitamin involved in energy production, as cited in "Advanced Nutrition and Human Metabolism." The DRI for women between the years of 19 and 50 is 1.3 mg daily, although that increases to 1.5 mg for those older than 50, and 1.9 mg if pregnant and 2 mg if lactating. Deficiency leads to microcytic anemia, depression and high blood pressure.
Vitamin B-7
Vitamin B-7, or biotin, is necessary for cell growth, the production of fatty acids and the metabolism of amino acids. The DRI for women of all ages is 30 micrograms daily even if pregnant, although that increases to 35 micrograms if lactating. Deficiency does not usually cause symptoms in adults.
Vitamin B-9
Vitamin B-9, or folic acid, is required to make and repair DNA, which is important during periods of rapid cell division and growth. The DRI for women of all ages is 400 micrograms daily, although that increases to 600 micrograms if pregnant and 500 micrograms if lactating. Deficiency in adults results in anemia, whereas deficiency in pregnant women can lead to neural tube birth defects, such as spina bifida, as cited in "Human Biochemistry and Disease."
Vitamin B-12
Vitamin B-12, or cobalamin, is also required to make DNA and to help maintain healthy nerve and red blood cells. The DRI for women of all ages is 2.4 micrograms daily, although that increases to 2.6 micrograms if pregnant and 2.8 micrograms if lactating. Deficiency results in macrocytic anemia, peripheral neuropathy, short-term memory loss and other issues with cognition.
References
- Institute of Medicine: Dietary Reference Intake: B-Vitamins
- "Contemporary Nutrition"; Gordon M. Wardlaw; 2010
- "Advanced Nutrition and Human Metabolism: 5th Edition"; Sareen S. Gropper and Jack L. Smith; 2009
- "Human Biochemistry and Disease"; Gerald Litwack; 2008
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