Many vegetarians, vegans and the elderly have a difficult time consuming their recommended daily allowance of vitamin B-12. It's rare for people in the United States to be severely deficient in vitamins B-1, B-6 or B12, but a diet that doesn't provide you with your required intake may make you more likely to develop certain medical problems.
Vitamin B-1 is also known as thiamin. Your body needs vitamin B-1 to break down the fats, protein and carbohydrates that you consume into adenosine triphosphate, or ATP, the primary form of energy used by your cells. Vitamin B-1 also supports the health and function of your immune and nervous systems. If your diet doesn't provide you with enough vitamin B-1, you may be more likely to develop cataracts. A man needs about 1.2 milligrams of vitamin B-1 each day, while a woman should have 1.1 milligrams.
Like vitamin B-1 -- and all of the other of the eight members of the B vitamin family -- vitamin B-6 aids in energy metabolism. Also known as pyridoxine, vitamin B-6 is required for the synthesis of mood-influencing hormones such as norepinephrine and serotonin. Not getting enough vitamin B-6 may increase your chance of mood disorders, such as depression. Vitamin B-6 helps regulate your body's level of homocysteine, an amino acid whose presence is linked to an increased risk of heart disease. A diet rich in vitamin B-6 may lower your chance of developing rheumatoid arthritis and age-related macular degeneration. Women who lack vitamin B-6 may have more severe premenstrual syndrome symptoms. All adults need at least 1.3 milligrams of vitamin B-6 daily.
Anyone who is age 19 years or older needs 2.4 micrograms of vitamin B-12, or cobalamin, each day. Vitamin B-12 aids in the production of red blood cells, DNA, RNA and an immune compound known as S-adenosylmethionine, or SAMe, that regulates mood. Along with vitamin B-6, vitamin B-12 lowers your homocysteine levels, which may decrease your risk of heart disease. If you don't get enough vitamin B-12, you may be more likely to develop anemia, and women with a vitamin B-12 deficiency may face a greater risk of breast cancer. Adequate vitamin B-12 may play a role in preventing male infertility, says the University of Maryland Medical Center.
Foods naturally rich in vitamin B-1 include whole grains, like whole-wheat bread or brown rice; beans, peas and lentils; and lean pork. Vitamin B-6 is found in high concentrations in salmon, bananas, potatoes and poultry. Vitamin B-12 can only be found in meat, seafood, poultry and dairy products. If you eat little or no animal products, you can get all three B vitamins from fortified foods like ready-to-eat breakfast cereal, though you may need to also take a dietary supplement. Don't begin supplementing with any vitamins until you've spoken to your doctor.