Do Vegetarians and Vegans Need a Vitamin B-12 Supplement?
- By Karen Moss, RDN
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- 06 Jun, 2018
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Hello VV Spotters! In my last nutrition post we talked about protein needs for vegetarians and vegans. For this post, let’s look at another nutrient that is important to pay attention to in the vegetarian and vegan (VV) diet: Vitamin B-12. Vitamin B-12 is an essential micronutrient that is needed for normal neurological function and to make red blood cells and DNA. Vegetarians, and vegans in particular, can be at risk for inadequate vitamin B-12 intake. Let’s talk about why that is.
Ever heard any of these before? B-12 can be made by bacteria in the mouth or the gut, so vegans don’t need a supplement…Don’t wash your vegetables and you can get B-12 from the soil left on them...I can get enough B-12 from fermented foods, nori, spirulina, or chlorella algae....These are myths and let’s set the record straight today with evidence-based information to help you decide if you need a B-12 supplement.
Food sources
Vitamin B-12 is not found in foods of plant origin. It is only found in animal sources where it is made either in the animal’s intestines or through it’s own diet. Therefore, fish, poultry, meat, eggs, and dairy foods are all good sources of B-12. Though it is true that our own small intestines can make some B-12, it is not enough to rely on to prevent deficiency. Vitamin B-12 from sources such as fermented foods, seaweeds, algae, or organic produce is either not supported by research or do not provide reliable amounts of B-12. This debunks the myths mentioned at the beginning of the blog and if you’d like to read more about it click here for research presented by Jack Norris, a health expert in the vegan community.
Because B-12 occurs naturally in animal foods only, fortified plant sources of B-12 are where those eating VV need to look for sources. Some examples include ready to eat cereals, meat analogues, soymilk, nutritional yeast, and protein bars. Be sure to check the label of foods when looking for fortified sources since not all types of these products are fortified and the amounts used in fortified products may change over time.
The Recommended Dietary Allowances of B-12 for a healthy adult is 2.4 mcg/day. If you’re a vegetarian that consumes dairy and eggs, you are more likely to get enough B-12. If you are a more strict vegetarian, or vegan especially, then you need to be sure to include fortified food sources and/or supplements.
Deficiency
Now that we’ve talked about sources of B-12, you can see how those who consume a VV diet could be at risk for deficiency. So what does B-12 deficiency look like?
"Vitamin B12 deficiency is characterized by megaloblastic anemia, fatigue, weakness, constipation, loss of appetite, and weight loss. Neurological changes, such as numbness and tingling in the hands and feet, can also occur. Additional symptoms of vitamin B12 deficiency include difficulty maintaining balance, depression, confusion, dementia, poor memory, and soreness of the mouth or tongue. The neurological symptoms of vitamin B12 deficiency can occur without anemia, so early diagnosis and intervention is important to avoid irreversible damage. During infancy, signs of a vitamin B12 deficiency include failure to thrive, movement disorders, developmental delays, and megaloblastic anemia."-Office of Dietary Supplements vitamin B-12 Fact Sheet
Another myth out there is that it takes years to become deficient in B-12. When someone becomes vegan, it is true that they likely have enough B-12 stored in their liver to prevent a severe deficiency for many years, however the beginning markers of B-12 deficiency can actually be found after only a few months. Therefore, you can imagine how vitally important it is for a pregnant or nursing VV mother to ensure adequate B-12 intake, so that her infant does not develop deficiency since the child will have no such reserves at birth. Untreated B-12 deficiency in a baby could result in permanent neurological damage, so be sure to consult a doctor or pediatrician about supplementation if you are pregnant, nursing, or feeding your child a VV diet. Older adults are also at an increased risk of deficiency since it is common as we age for the stomach to make less acid, making absorption of B-12 a problem. Other GI disorders can put one at risk as well.
Studies have shown that vegans who did not supplement with B-12 showed higher levels of homocysteine, a byproduct of protein metabolism, that when elevated is associated with increased risk of dementia, heart disease, and stroke.
Folate or folic acid, which VV eaters tend to get high levels of in their diet, can actually mask a B-12 deficiency by correcting anemia, but not fixing and maybe even exacerbating neurological damage. It is not recommended for healthy adults to consume more than 1,000 mcg/day of folic acid a day.
It is a good idea for all VV eaters to talk to their doctors about testing their B-12 status.
Supplements
Most supplements come in the form of cyanocobalamin. Other forms you may see are methylcobalamin and hydroxocobalamin. Good news is that the form of B-12 used in supplements and fortified foods is made by bacteria and is not sourced from animals (but always be sure to check the other ingredients in the supplement to ensure it is vegan if that’s your goal). No one form of B-12 has been shown to be more bioavailable or better absorbed than others. Absorption depends more on the body’s ability to absorb it. In fact, a healthy adult who takes a 500 mcg supplement probably only absorbs about 10 mcg of it. Sublingual tablets or lozenges are not superior, so don’t be fooled by any marketing saying it is. Intramuscular injections by prescription can be used for severe deficiency or for those with malabsorption issues.
Take home recommendations from the Vegetarian Nutrition Dietetic Practice Group:
-If you are a vegetarian, especially a vegan, you should ingest a reliable vitamin B12 source, such as fortified foods or supplements.
-Ask your doctor if your vitamin B12 level should be checked on an annual basis.
-Regularly use foods fortified with vitamin B12 and/or take vitamin B12 supplements.
-Ensure your vitamin B12 is adequate prior to becoming pregnant, during pregnancy, and while breastfeeding.
-Older vegetarians, especially vegans, may need higher doses of B12 due to age-related absorption problems.
-Higher doses may be needed for individuals who are already deficient.
Learn more about this topic by perusing the sources for this post. Thanks for reading!
Sources:
Position of the Academy of Nutrition and Dietetics: Vegetarian Diets. Melina, VesantoCraig, WinstonLevin, Susan et al. Journal of the Academy of Nutrition and Dietetics , Volume 116 , Issue 12 , 1970 – 1980.
