Adequate B-12 intake is vital for neurological function, normal blood formation and cellular processes, like making new DNA and RNA. Your vitamin B-12 recommendation changes throughout your younger years, but as an adult, it remains the same. The only time you need more is if you are pregnant or breastfeeding. Meeting your recommended intake is important, since a deficiency can be dangerous to your health.
Children between 4 and 8 years of age need 1.2 micrograms of daily B-12, which increases to 1.8 micrograms through the age of 13. As a teenager or adult of either gender, you need 2.4 micrograms of vitamin B-12 from the age of 14 and all throughout adulthood, says the Office of Dietary Supplements. Women, however, sometimes need more. During pregnancy, you'll need to increase your B-12 intake to 2.6 micrograms and then to 2.8 micrograms while you are breastfeeding.
Several types of over-the-counter supplements, including multivitamins and vitamin B complex pills, provide as much as 100 percent of your vitamin B-12 recommendation. Vitamin B-12 is unlikely to cause adverse health effects in healthy individuals, so there is no toxic level established. Your body can only absorb a small amount at a time, resulting in minimal, if any, problems with toxicity. Even if you take a 500-microgram B-12 supplement, your system only absorbs roughly 10 micrograms, explains the Office of Dietary Supplements. Any leftover B-12 flushes out with urine. If you think you need to take a B-12 supplement, check with your health care provider first, to ensure it doesn't interact negatively with your other medications.
Ideally you should get enough B-12 from your diet that you do not need to take supplements. Seafood, fish, meat, poultry, eggs and dairy are some of your best options for high levels of B-12. Clams are loaded with B-12, providing more than 80 micrograms in a 3-ounce cooked serving. Three ounces of broiled trout offer about 5.5 micrograms, while the same amount of salmon has nearly 5 micrograms. You'll get approximately 1.4 micrograms from 3 ounces of cooked beef sirloin and 1.3 micrograms from the same amount of roasted turkey. One whole egg offers around .6 micrograms, most of which is in the yolk. If you're not a big fan of meat, have a bowl of fortified breakfast cereal in the morning. Most cereals provide as much as 100 percent of your daily B-12 needs, along with other nutrients.
Vitamin B-12 naturally binds with protein in foods. Hydrochloric acid in your stomach has to free B-12 molecules before it can bind with the protein called intrinsic factor and absorb through intestinal walls. As you age, your body doesn't produce as much stomach acid and B-12 can't get into a free state. Your body automatically excretes some of the B-12 you consume, sometimes resulting in a deficiency. In some cases, pernicious anemia, an autoimmune disorder, destroys the lining of your stomach, causing low levels of hydrochloric acid and intrinsic factor, further decreasing B-12 concentrations. Having a B-12 deficiency leads to megaloblastic anemia, a condition that forces red blood cells to be larger than normal. These cells have a hard time properly distributing oxygen throughout your body, making you feel extremely weak. In severe cases, you'll experience neurological symptoms, like numbness, tingling, confusion and poor balance.
Melodie Anne Coffman specializes in overall wellness, with particular interests in women's health and personal defense. She holds a master's degree in food science and human nutrition and is a certified instructor through the NRA. Coffman is pursuing her personal trainer certification in 2015.