As you can see, the B vitamins are essential for an astonishing array of life functions. Fortunately, most of us will get all of the B vitamins we need by eating a well-balanced diet. Some people swear by a B-complex supplement every day, but based on the wide variety of foods containing these vitamins, a supplement may not be necessary.
Researchers from the Hope Heart Institute say that up to 30 percent of people over age 50 have lost the ability to absorb adequate vitamin B12 from meat or dairy products. Other people need only 2.4 mg. a day -- the amount found in three ounces of beef -- but researchers recommend that older Americans eat fortified cereal or grains or take a daily vitamin supplement. (If you need extra calories and protein, a supplement drink, containing all the appropriate vitamins, is an alternative.) Check the chart below for a quick, but thorough, look at the basics of the B-complex vitamins:
|Recommended Daily Allowance (RDA)* in mg (B12 is in µg)||Food Sources||Importance||When You Take Too Much||When You Take Too Little|
|Thiamine (B1)||I=0.3-0.4; C=0.7-1.0; A=1.0-1.5||cereal, bread, meat, rice, yeast, corn, nuts||carbohydrate metabolism, nervous system||none known||beriberi (anemia, paralysis), movement & memory effects|
|Riboflavin (B2)||I=0.4-0.5; C=0.8-1.2; A=1.2-1.8||grains, milk, meat, eggs, cheese, peas||maintains skin, mucous membranes, eyes, nerve sheaths||None known||skin & oral problems, anemia|
|Niacin (B3)||I=5-6; C=0.8-1.2; A=1.2-1.8||meat, milk, eggs, fish, legumes, potatoes||healthy skin, nerves & GI tract, metabolism of food||flushing, itching, cramps, nausea, skin eruptions||pellagra (diarrhea, dermatitis, dementia)|
|Pyridoxine (B6)||I=0.3-0.6; C=1.0-1.4; A=1.4-2.0||organ meats, brown rice, fish, butter, soybeans||metabolism of food, amino acids||nerve damage||skin & nerve damage, confusion, mouth irritation|
|Folic acid (B9)||I=25-35; C=50-100; A=150-180||yeast, liver, green vegetables, whole grain cereal||DNA, hemoglobin synthesis, formation of blood cells, protein metabolism||convulsions, disrupted zinc absorption||anemia, mouth irritation, poor growth|
|Pantothenic acid||N/A; made by our intestines||meats, legumes, whole-grain cereals||breakdown of carbohydrates, lipids, amino acids||diarrhea||none known|
|Biotin||N/A; made by our intestines||beef liver, egg yolk, brewer's yeast, mushrooms||functions as coenzyme in caroboxylation reactions||none known||scaly dermatitis|
|B12||I=0.3-0.5; C=0.7-1.4; A=2.0||liver, meat, eggs, poultry, milk||metabolism of food, blood cell formation, DNA synthesis||none known||pernicious anemia, mouth irritation, brain damage|
*I=infant; C=child; A=adult. Please note that vitamin ranges account for differences in age and gender. Some of the vitamins should be increased during pregnancy and for lactating mothers.
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