First of all, it is absolutely essential for vegans and anyone eating a diet of predominantly plant foods to get their B-12 from a supplement or several servings of fortified foods (foods with added B-12) daily. There are no plant foods that are reliable sources of B-12 and vegans that choose to forgo supplements or fortified foods are putting themselves at serious risk. So what kind of supplement and how much is recommended?
The most reliable form of B-12 is cyanocobalamin. Many supplements contain methylcobalamin instead (or a different form) but we lack sufficient evidence to support the efficacy of these alternative forms, so look for cyanocobalamin. Most adults can meet their B-12 needs with one 2,500 mcg supplement per week or else a smaller daily dose of 250 mcg. Because everyone (including non-vegans) loses some ability to absorb B-12 as we age, adults over the age of 65 should consider taking a larger daily dose of 1,000 mcg. Ideally, choose a chewable, sublingual, or liquid supplement and take it on an empty stomach. If you prefer you can instead ensure you are eating 3 or more servings of B-12 fortified foods every day. Fortified foods to look for include plant-based milks, nutritional yeast and some breakfast cereals, but not all of these products are fortified so it is important to check the labels and look for at least 25% DV. In some relatively rare cases of severe malabsorption it may be necessary to take B-12 injections but only if recommended by your doctor for a persistent deficiency.
If you have been vegan for some time and have not been taking B-12 supplements, it is recommended to start immediately, but also ask your doctor about screening for deficiency. Deficiency of B-12 can take some time to develop and there are often no symptoms early on, but the eventual consequences can be serious and irreversible. If you do have any symptoms of B-12 deficiency, including unexplained numbness in hands, legs or feet, a swollen or inflamed tongue, walking difficulties such as staggering or balance issues, cognitive difficulties such as memory loss, or anemia it is recommended to seek screening for B-12 deficiency to ensure you are correcting the deficiency appropriately and as soon as possible. Rather than testing your blood level of B-12, which has been shown to miss cases of deficiency, ask your doctor about a urine test for methylmalonic acid (MMA), which is more reliable. If you are not having any symptoms and are new to a plant-based diet, simply start taking a regular reliable dose of B-12; screening is not necessary in that case.
Why do some vegans choose not to supplement? Some feel that a plant-based diet is natural and supplements are not natural. Some have been given misleading information about potential plant sources of B-12. Some are concerned that taking a supplement signals something lacking in their diet. It’s important to consider that our “unnatural” modern ways of living have changed our need for supplementation for optimal health, regardless of the diet we choose. At some point in human history it may have been possible to get adequate B-12 without eating animal foods. Soil bacteria do contain B-12, however the current conditions of our soil and the more sanitized lifestyles that we live, make it currently impossible to rely on bacterial contamination as a source. A vegan or plant-based lifestyle has enormous benefits for animals, for our health and for the planet, and we shouldn’t let the lack of availability of one nutrient stop us from choosing such a lifestyle. But if we want to be successful with a plant-based lifestyle long-term, supplemental B-12 is necessary, cheap and easy.
ABOUT THE AUTHOR:
Rebecca Aslam, MS, RD, LDN is a dietitian who has been working in clinical practice in a variety of settings for more than seven years. She is a life-long follower of a plant-based diet. She enjoys working with individuals and groups to facilitate behavior change and to educate on healthy, sustainable eating habits.