Thanks to its role in energy metabolism, vitamin B12 is often touted as a weight-loss and energy-boosting aid. B12 is an essential water-soluble vitamin found in a variety of foods, including fish, shellfish, red meat, poultry, eggs, many breakfast cereals and dairy products. It helps maintain healthy nerve and red blood cells, and is also needed to make DNA, according to the Mayo Clinic. Vitamin B12 deficiency can lead to anemia, fatigue, weakness, neurological changes (including numbness and tingling in the hands and feet), difficulty maintaining balance, depression and confusion, among other conditions, according to the National Institutes of Health. Get tested to see whether your body is breaking Vitamin B12 down properly. About 50 percent of the U.S. population cannot metabolize vitamin B12 properly due to a genetic glitch, says nationally known nutritionist and bestselling author Ann Louise Gittleman, Ph.D. “It’s a very individual thing,” Gittleman says.
“You need to figure out if you are deficient or have too much of it. If your body is not breaking it down properly, you’ll need a supplement that will help your body utilize this important nutrient. Prepare for a B12 test by making sure you don't eat or drink anything for six to eight hours prior to the test, according to the NIH’s Office of Dietary Supplements. B12 levels are analyzed via a blood test. Tell your health care provider about all medicines you are taking, including over-the-counter and herbal medication. Drugs that may affect test results include colchicine, neomycin, para-aminosalicylic acid and phenytoin (Dilantin), according to the agency. When you get your results, check to see if your values are normal. Normal values are 200 to 900pg/mL (picograms per milliliter). Normal value ranges may vary slightly among different laboratories That's why it's important to talk to your doctor about what your specific test results mean, according to the agency.
Make sure you don't take too much B12. There is no identified tolerable upper intake level, or UL, for vitamin B12 due to its low potential for toxicity, according to NIH. However, “I wouldn’t go over the recommended daily allowance. I wouldn’t err on the side of too much or too little,” Gittleman says. The RDA for B12 is 2.4mcg per day for adults. Those who need supplements can get them via injection or as supplements in pill, sublingual or liquid form. Learn to add the foods you eat into your daily allotment if you choose to take a supplement, Gittleman advises. “I’d factor in any foods I eat, such as beef, that are a rich source,” she says. Structure your diet to get enough B12 without taking supplements. According to the Mayo Clinic, a day's supply of vitamin B12 can be obtained by eating one chicken breast plus one hard-boiled egg plus 1 cup plain low-fat yogurt, or 1 cup milk plus 1 cup raisin bran. It is important not to try to self-diagnose a vitamin deficiency.
You can find selected sources of vitamin B 12 on the Dietary Supplement Fact Sheet published by the National Institutes of Health Office of Dietary Supplements (see Resources). Which Foods Contain B12? What Causes Low B12 Levels? The Best Method to Increase Vitamin B12 Levels Adverse Reactions to Vitamin B12 Shots What Is the Normal Intramuscular Dose of Vitamin B12? Vitamin B12 Drug Side Effects How Often Can You Inject B12? Are There Weight-Loss Benefits of Vitamin B12? How to Give B12 IM Injections Vitamin B12 Shots Vs. Pills The Best Places to Give Vitamin B12 Injections Symptoms of Low B12 Sublingual Vitamin B12 vs. Injectable B12 How Fast Will B-12 Work? Symptoms of Vitamin B-12 DeficiencyThe below doses are based on scientific research, publications, traditional use, or expert opinion. Many herbs and supplements have not been thoroughly tested, and safety and effectiveness may not be proven. Brands may be made differently, with variable ingredients, even within the same brand.
The below doses may not apply to all products. You should read product labels, and discuss doses with a qualified healthcare provider before starting therapy.Recommended dietary amounts (RDAs) are 2.4 micrograms daily for ages 14 years and older, 2.6 micrograms daily for pregnant females, and 2.8 micrograms daily for breastfeeding females. Those over 50 years of age should meet the RDA by eating foods reinforced with B12 or by taking a vitamin B12 supplement. A doctor and a pharmacist should be consulted for use in other indications. For canker sores, sublingual (under the tongue) vitamin B12 has been given daily for six months. For claudication, a total daily dose of 1.5 milligrams of vitamin B12 was taken by mouth in divided doses of 0.5 miligrams three times daily for six months. For vitamin B12 deficiency, 125-2,000 micrograms of cyanocobalamin has been taken by mouth daily for up to 2.5 years or longer. Five hundred micrograms of sublingual (under the tongue) vitamin B12 has been used daily for up to four weeks.
The following doses have been given intravenously (through the veins): 1,000 micrograms of intramuscular cobalamin once daily for 10 days (after 10 days, the dose was changed to once weekly for four weeks, followed by once monthly for life); 1,000 micrograms of intramuscular cyanocobalamin given on days 1, 3, 7, 10, 14, 21, 30, 60, and 90 of treatment. For vitamin B12 deficiency caused by long-term PPI therapy, cyanocobalamin nasal spray has been used for eight weeks. The exact dosage is unclear. One study tested intranasal vitamin B12 replacement therapy (500 micrograms weekly). For prevention of anemia, the following doses have been taken by mouth: 2-10 micrograms of vitamin B12 daily combined with iron and/or folic acid for up to 16 weeks; 100 micrograms of vitamin B12 every other week plus daily folic acid and/or iron for up to 12 weeks. For mental performance, the following doses have been taken by mouth: 0.05-1 milligram vitamin B12 taken daily for four weeks to 5.4 years;
10 micrograms or 50 micrograms of cyanocobalamin daily for one month; and one milligram of cyanocobalamin weekly for four weeks. One 1,000 microgram vitamin B12 injection has been used daily for five days, followed by one 1,000 microgram injection monthly for five months. Additionally, 1000 microgram injections have been used weekly for four weeks or monthly for six months. For cyanide poisoning, an intravenous (IV) infusion of five grams of hydroxocobalamin (up to 20 grams) has been used. For depression, one milligram of cyanocobalamin, through intramuscular injections, was used weekly for four weeks. For hereditary sideroblastic anemia, 100 micrograms of intramuscular vitamin B12 has been used monthly, with or without daily folic acid, for up to four months. Recommended dietary amounts (RDAs) are lacking for all age groups; therefore, adequate intake (AI) levels have been used instead. The RDAs and AI levels of vitamin B12 are as follows: for infants 0-6 months old, 0.4 micrograms (AI);