If you are vegan or are planning to become one, chances are that you’ve been warned of a possible vitamin B12 deficiency. Since the vitamin is found chiefly in animal food, deficiency is scarily prevalent in people who shun any form of animal food.
Risk factors for vitamin B12 deficiency due to poor absorption include:
- Stomach or intestinal disorders
- Long-term use of antacids and proton pump inhibitors
Nearly 40% of the American population suffers from low or near-deficient levels of B12, and vegetarianism has caused severe B12 deficiency in countries like India, Mexico, parts of Central and South America, and Africa.1 2 For men aged 19–50 years, a daily intake below 2 mcg can cause a deficiency, whereas for women anything below 2.4 mcg is problematic.
While the richest sources of B12 are animal foods like liver, clams, oysters, mussels, milk, eggs, fish, beef, lamb, and pork, there’s some hope for vegans too. Here’s a look at the vegan sources of vitamin B12.
1. Nutritional Yeast
Depending on the brand, nutritional yeast packs up to 24 mcg of vitamin B12 per tablespoon.3 It is also rich in vitamins B1, B2, B3, and B6. You could sprinkle nutritional yeast over popcorn, add it to pasta sauces, or stir it into soups.
2. Fortified Breakfast Cereal
Fortified breakfast cereals are one of the most readily available sources of vitamin B12 for vegans, containing as much as 6 mcg vitamin B12 per serving, depending on the brand.4 Studies have proven that consumption of fortified cereal for breakfast or supper can increase the levels of vitamins B12, B1, B6, folate, and iron.5
3. Fortified Plant-Based Milk
Consuming fortified plant-based milk is a good way to get 50% of your B12 requirements in, depending on the brand. It is also rich in calcium, vitamin B2 and helps increase body weight and folate or vitamin B9 in children.6 Vegan or vegetarian mothers who have adequate B12 stores need not worry about their babies’ vitamin B12 fix for the first 6 months. Babies will get it from breastmilk alone.7 Once breastfeeding stops, the nutrient gap can be filled with fortified soy, oat, flaxseed, pistachio, almond, or coconut milk.
4. Fortified Rice
Irrespective of how it is cooked, fortified rice is a good source of B12.8 It has been proven that rice fortified with multiple micronutrients, including B12, improved the B12 levels in Indian school children. As B12 is involved in the process of energy production in the body, this significantly improved their physical performance.9
5. White Button Mushroom
Recent research has found traces of vitamin B12 in the outer skin of white button mushrooms.10 One cup of raw white mushrooms contains up to 0.03 mcg of the vitamin.11 Hence, while white button mushrooms might not be the primary source of the vitamin, you could incorporate them into your diet to vary your sources. However, you need to be especially careful since cooking destroys the water-soluble B vitamins. The best way to retain the B12 content is to steam the mushrooms.
Seaweed, Nori, Tempeh, And Yeast May Not Help
Yeast, nori, seaweed, or tempeh and miso may contain the inactive form of vitamin B12, which may interfere with absorption of active B12 in the body.
Although alternative sources of B12 like seaweed, fermented soy products like tempeh and miso, and yeast have been identified, whether they are reliable sources of this vitamin is debatable. This is because there are active and inactive forms of this vitamin in foods and the inactive form can actually interfere with vitamin B12 absorption in the body. And these vegan sources were found to be lacking in active vitamin B12.12
If you cannot include the above-mentioned food items in your diet due to taste preferences, allergies, or availability issues, go for fortified food or B12 supplements.
Your body can’t absorb all the B12 available in supplements. And the higher the dose, lower the absorption.
Vitamin B12 is available singly or in multivitamin pills. It is recommended that vegans, vegetarians, and pregnant women target 6 to 30 mcg B12 daily through fortified foods and supplements. Adults above 50 are advised to take 100 to 400 mcg B12 supplements since aging decreases the rate of absorption.13 In a study conducted in older men to see if supplements improved B12 intake, it was found that 80% of the users met the estimated average requirement (EAR) of the vitamin through supplements.14
Vitamin B12 is also available as injections, which can help pernicious anemia patients who cannot absorb the vitamin when it is administered orally. Oral sprays or sublingual tablets (to be placed under the tongue) may also help as they do not need to be digested.
Take B12 In Small And Frequent Doses
Your body absorbs vitamin B12 from food in a number of steps. To put it simply, first, stomach acid separates the B12 from food proteins. Then the free B12 binds to a protein called intrinsic factor (IF). This combined form is then absorbed in your small intestine. A very low percentage, about 1%, gets absorbed through passive diffusion. So essentially, the rate of absorption depends on the amount of IF secreted by your stomach.
It is estimated that only 56% of 1 mcg vitamin B12 gets absorbed at a time. So though vitamin B12 from supplements is available in a free form, absorption may be only slightly better than from foods. Taking above 2 mcg B12 at a time exceeds the intrinsic factor’s binding capacity and decreases the rate of absorption. In fact the higher the dose, lower the degree of absorption.15 16
So you should get your B12 from supplements in small but frequent doses. However, adults above 50 are advised to take high doses of supplements so that the amount absorbed through passive diffusion is significant.
Can You Overdose On Vitamin B12?
Since vitamin B12 is water soluble, it is flushed out of the body through urine. And until recently, a vitamin B12 overdose wasn’t known to have any adverse or serious side effects. However, now, studies suggest that long-term vitamin B12 supplementation can increase the risk of colorectal cancer and lung cancer (particularly in smokers) in men.17 18
That apart, very high B12 concentrations (most likely > 1,000 pmol/L) in the blood can lead to acne-like skin problems in some people.19 It may also cause serious damage to optic nerves in people with Leber’s disease.20 So try to work with your diet, add in fortified food and supplements for your B12 requirement and stay healthy. Also, ask your doctor about B12 supplementation if you have abnormal levels of red blood cells in your body, are pregnant, or are on other medications
[expert_opinion expertname=’kimberlylackey’ opinion=”B-12 sublingual and injectable supplements are the way to provide optimal B-12 levels. Bypassing the gut to absorb the nutrient is the quickest way to boost these levels. Having optimal B-12 levels is non-negotiable for a healthy immune system.”]
|↑1||McBride, Judy. “B12 deficiency may be more widespread than thought.” United States Department of Agriculture (2000).|
|↑2||Stabler, Sally P., and Robert H. Allen. “Vitamin B12 deficiency as a worldwide problem.” Annu. Rev. Nutr. 24 (2004): 299-326.|
|↑3||Full Report (All Nutrients): 45067042, PREMIUM NUTRITIONAL YEAST SEASONING, UPC: 074305066054. United States Department Of Agriculture.|
|↑4||Vitamin B12- Fact Sheet. NIH.|
|↑5||Powers, Hilary J., Mark Stephens, Jean Russell, and Marilyn H. Hill. “Fortified breakfast cereal consumed daily for 12 wk leads to a significant improvement in micronutrient intake and micronutrient status in adolescent girls: a randomized controlled trial.” Nutrition Journal15, no. 1 (2016): 69.|
|↑6||Kuriyan, Rebecca, Prashanth Thankachan, Sumithra Selvam, Maria Pauline, K. Srinivasan, Shilpa Kamath-Jha, Sophie Vinoy, Situn Misra, Yvonne Finnegan, and Anura V. Kurpad. “The effects of regular consumption of a multiple micronutrient fortified milk beverage on the micronutrient status of school children and on their mental and physical performance.” Clinical Nutrition 35, no. 1 (2016): 190-198.|
|↑7||Vegan Infants & Toddlers. Vegan Health.|
|↑8||Wieringa, Frank T., Arnaud Laillou, Christophe Guyondet, Vincent Jallier, Regina Moench‐Pfanner, and Jacques Berger. “Stability and retention of micronutrients in fortified rice prepared using different cooking methods.”Annals of the New York Academy of Sciences 1324, no. 1 (2014): 40-47.|
|↑9||Thankachan, Prashanth, Jee Hyun Rah, Tinku Thomas, Sumithra Selvam, Vani Amalrajan, Krishnamachari Srinivasan, Georg Steiger, and Anura V. Kurpad. “Multiple micronutrient-fortified rice affects physical performance and plasma vitamin B-12 and homocysteine concentrations of Indian school children.” The Journal of Nutrition 142, no. 5 (2012): 846-852.|
|↑10||Koyyalamudi, Sundar Rao, Sang-Chul Jeong, Kai Yip Cho, and Gerald Pang. “Vitamin B12 is the active corrinoid produced in cultivated white button mushrooms (Agaricus bisporus).” Journal of agricultural and food chemistry57, no. 14 (2009): 6327-6333.|
|↑11||Vitamin B12 in Vegetarian Diets. Oregon State University.|
|↑12||Reed Mangels. Vitamin B12 in the Vegan Diet. The Vegetarian Resource Group.|
|↑13||Vitamin B12. Oregon State University.|
|↑14||Sebastian, Rhonda S., et al. “Older adults who use vitamin/mineral supplements differ from nonusers in nutrient intake adequacy and dietary attitudes.” Journal of the American Dietetic Association 107.8 (2007): 1322-1332|
|↑15||Vitamin B12. NIH.|
|↑16||Herbert, Victor. “Recommended dietary intakes (RDI) of vitamin B-12 in humans.” The American journal of clinical nutrition 45, no. 4 (1987): 671-678.|
|↑17||Ishihara, Junko, Tetsuya Otani, Manami Inoue, Motoki Iwasaki, Shizuka Sasazuki, Shoichiro Tsugane, and Japan Public Health Center-based Prospective Study Group. “Low intake of vitamin B-6 is associated with increased risk of colorectal cancer in Japanese men.” The Journal of Nutrition 137, no. 7 (2007): 1808-1814.|
|↑18||Brasky, Theodore M., Emily White, and Chi-Ling Chen. “Long-term, supplemental, one-carbon metabolism–related vitamin b use in relation to lung cancer risk in the Vitamins and Lifestyle (VITAL) cohort.” Journal of Clinical Oncology 35, no. 30 (2017): 3440-3448.|
|↑19||Arora, Megha K., Shashi Seth, and Surabhi Dayal. “Homocysteine, folic acid and vitamin B12 levels in females with severe acne vulgaris.” Clinical Chemistry and Laboratory Medicine 50, no. 11 (2012): 2061-2063.|
|↑20||Vitamin B12. University Of Maryland Medical Center.|