Yes, vitamin B-12 – and all of the B vitamins – play an important role in digestion. They help you convert carbohydrates to sugar so your body can use them for energy and help you metabolize proteins and fats. This doesn't mean you should take large doses of vitamin B-12 in the hope of boosting your metabolism. Some people will benefit from taking vitamin B-12 supplements, but talk to your doctor before taking this or any other kind of dietary supplement.
To break down fats and carbs in your diet, you need about 2.4 mcg – micrograms – of vitamin B-12 in your daily diet. Pregnant and nursing women need more and infants, and children need it in amounts relative to their body weight – about 0.4 mcg up until age 6 months, 0.5 mcg for 7 to 12 months, 0.9 mcg from age 1 to 3, 1.2 mcg from age 4 to 8 and 1.8 mcg from 9 to 13. In addition to helping you metabolize food, vitamin B-12 helps your body produce red blood cells and promote proper nervous system function. Children need vitamin B-12 to grow and develop and may experience muscle weakness if they don't get enough vitamin B-12.
If your diet includes eggs, dairy products, meat, poultry and shellfish, you probably get all of the vitamin B-12 you need to break down fats and carbs. A large egg contains 0.45 mcg of vitamin B-12, virtually all of it in the yolk. An 8 oz. glass of non-fat milk contains 1.23 mcg of vitamin B-12, and a 3 oz. serving of beef tri-tip roast contains just over 1 mcg of vitamin B-12. Vegans can obtain vitamin B-12 from beans, green leafy vegetables and some fortified breakfast cereals but may not get enough from these sources to meet their needs.
More than 1 in 30 adults older than 51 in the United States suffer from vitamin B-12 deficiency, according to the Centers for Disease Control and Prevention. People with untreated pernicious anemia – caused by the inability to absorb vitamin B-12 – may need to take a vitamin B-12 supplement as may people who've undergone stomach surgery. Vegans may not get enough vitamin B-12 in their diets. Pregnant women deficient in vitamin B-12 may pass the deficiency to their children, especially if they breastfeed them.
If you want to break down fats and carbs to achieve weight loss, exercise provides a healthy way to speed the process. Exercise can help burn fats and carbs as well as improve your cholesterol levels. If you think you need more vitamin B-12 than your diet affords, talk to your doctor about taking supplements. Signs of vitamin B-12 deficiency include fatigue, sadness, shortness of breath, loss of vision and heart palpitations.
- University of Maryland Medical Center; Vitamin B-12; Linda Vorvick, M.D.: March 14, 2009
- Centers for Disease Control and Prevention; Learn More About Vitamin B-12 Deficiency; Aug. 3, 2009
- National Heart, Lung and Blood Institute; What is Pernicious Anemia?; April 2011
- United States Department of Agriculture Nutrient Database