Vitamins B1 (thiamine), B6 and B12 are important to the functioning of the nervous and immune systems. Vitamins B1 and B6 help convert carbohydrates and other nutrients into glucose. Vitamin B6 also helps regulate mood and cognitive functioning by stabilising blood-sugar levels and by promoting synthesis of the neurotransmitters serotonin and dopamine. Vitamins B12 and B6 are essential to the production of red-blood cells, which deliver oxygen throughout the body. Because the body cannot store B vitamins (except for B12), you need to consume B-rich foods on a regular basis.
Food Sources for Vitamin B1
Adding an ounce of wheat germ to your breakfast cereal will provide 35 per cent of your daily B1 needs. Serve that meal with orange juice, and you'll add another 18 to 20 per cent. Sources containing about 10 per cent of the RDA for B1 include a serving of lentils or other cooked beans, raw sunflower seeds, peas, butternut squash, fresh oranges and brown rice. A slice of whole-grain bread contributes about 5 per cent of your daily needs.
Food Sources for Vitamin B6
One serving of potatoes, bananas or most types of beans can help you meet about a third of your daily B6 requirement. A helping of chicken, pork or fortified oatmeal provide about one-fifth to one-quarter. You can meet an additional 10 to 15 per cent of your B6 needs by consuming one serving of roast beef, rainbow trout, sunflower seeds, tomato juice, salmon, avocado, tuna, butternut squash, blackstrap molasses or wheat bran. Peanut butter and other nuts per serving contain about 8 per cent of the RDA for B6.
Food Sources for Vitamin B12
Clams, trout, salmon, tilapia and beef are excellent sources of B12, providing 70 per cent or more of your daily requirement. A can of tuna contains about 35 per cent of the RDA for this vitamin. Vegetarians can get all the B12 they need from dairy and eggs--a serving of milk or yoghurt meets 20 per cent of your daily B12 needs. Two eggs contain about the same. Many breakfast cereals are also B12-fortified.
Vegan Sources for Vitamin B12
The Vegetarian Society's website recommends that vegans take a vitamin B12 supplement or consume B12-fortified soy milk, breakfast cereals or margarine. Seaweed and fermented soybean products are not a reliable source of vitamin B12 as was previously thought, according to the website. Vegans can also help meet their B12 needs with Red Star nutritional yeast, which has been shown to contain active B12, according the Vegetarian Resource Group website. Nutritional yeast can be purchased as flakes or powder. It is often used to add a cheesy texture and taste to vegan soups, stews, casseroles and pasta dishes.
Deficiency symptoms include fatigue, weakness and neurological problems. Because B6 and B12 are important to red-blood-cell function, deficiencies in these vitamins may result in a type of anaemia similar to iron-deficient anaemia, according to the NIH website. People who frequently drink alcohol may need to consume greater amounts of B1 and B6 because alcohol consumption hinders absorption and increases excretion of these vitamins.