Your cells need only tiny amounts of vitamin B12, but that little bit is essential. This hardworking vitamin helps to make DNA, form red blood cells, and keep nerves functioning properly. Not getting enough B12 can lead to fatigue, weakness, loss of appetite, nerve problems, and anemia. It can also cause cognitive problems, such as confusion and dementia. Studies show that vegans, who consume no animal products, are likely to have low blood levels of vitamin B12. Vegan children and adults need to get B12 from supplements or fortified foods. Anyone with digestive problems could have problems absorbing sufficient B12. Older adults are also at risk for vitamin B12 deficiency. With age, the intestine is less able to absorb the vitamin. Excess alcohol consumption causes a significant drop in B12 levels. Older adults may benefit from consuming fortified foods, taking an oral supplement, or getting B12 injections. How Much Do You Need? According to the Institute of Medicine, the recommended dietary allowance (RDA) for vitamin B12 varies with age: Age 0–6 months: 0.4 micrograms (mcg) Age 7–12 months: 0.5 mcg Age 1–3 years: 0.9 mcg Age 4–8 years: 1.2 mcg Age 9–13 years: 1.8 mcg Age 14 years and older: 2.4 mcg Where Can You Get B12? Vitamin B12 occurs naturally only in animal foods. These include meat, fish, poultry, eggs, milk, and milk products. Here are some natural sources of this vitamin: Beef liver, 3 ounces, 70.7 mcg Clams, 3 ounces, 15.8 mcg Sardines, 3 ounces, 7.6 mcg Salmon, 3 ounces, 4.8 mcg Rainbow trout, 3 ounces, 3.5 mcg Tuna, canned, 3 ounces, 2.5 mcg Ground beef, 3 ounces, 2.4 mcg Lamb, 3 ounces, 2.3 mcg Vanilla milkshake, 11 ounces, 1.6 mcg Rice drink, unsweetened, 8 ounces, 1.5 mcg Cottage cheese, low-fat, 1 cup, 1.4 mcg Whole milk, 1 cup, 1.1 mcg Pork loin, 3 ounces, 0.5 mcg Cheese, American, 1 ounce, 0.4 mcg Egg, one medium, 0.4 mcg Chicken, 3 ounces, 0.3 mcg Ice cream, vanilla, ½ cup, 0.3 mcg You can also get B12 from fortified foods, vitamin supplements, and nutritional yeast products. Many ready-to-eat breakfast cereals are fortified with vitamin B12. They provide about 1.5 to 6 mcg per serving. Some rice and soy beverages are also fortified with B12. As for supplements, the amount of vitamin B12 they contain varies. Nutritional yeast is grown for its nutritional value. It is not a live yeast like baking yeast. A tablespoon or two of nutritional yeast flakes stirred into a beverage or food will meet your daily B12 needs. Read Nutrition Labels Check the nutrition facts panel of fortified foods and dietary supplements to find out how much vitamin B12 they contain. Instead of showing the exact amount of B12, the label will state the percentage of the daily value (DV) that one serving provides. For example, a label that states “Vitamin B12 - 25% DV” means that one serving has 25% of your daily need. Key Takeaways Not getting enough vitamin B12 can lead to fatigue, weakness, appetite loss, nerve problems, anemia, and cognitive problems. Vitamin B12 occurs naturally only in animal foods: meat, fish, poultry, eggs, milk, and milk products. You can also get B12 from fortified foods, vitamin supplements, and nutritional yeast products