Do You Need a Vitamin B12 Supplement If You’re Taking a GLP-1?

WHILE GLP-1 MEDS have been game changers for weight management, they’ve also introduced some challenges for people looking to lose weight. They reduce appetite and help you feel satisfied sooner, but that can make it more challenging to get all the nutrients your body needs.One of the nutrients GLP-1 users may get less of is Vitamin B12. On social media, people discussing life on GLP-1s often bring up eating more foods high in B12 or recommending B12 supplements when complaints of side effects like fatigue and headaches come up.Here’s what you need to know about vitamin B12 and GLP-1s along with how to make sure you’re getting enough.Why Vitamin B12 Is Important to the Body VITAMIN B12, ALSO known as cobalamin, is an essential vitamin that cannot be produced by the body. It must come from food or supplements, says internist Jennifer Chung, MD.Vitamin B12 supports several important bodily functions. It’s involved in the production of red blood cells, creation of DNA, and maintenance of a healthy nervous system. The demand for vitamin B12—the recommended daily intake of vitamin B12 for most adults is 2.4 micrograms—doesn’t go away even when you’re consuming fewer calories.What Happens When Vitamin B12 Levels Are Too Low?WHEN VITAMIN B12 levels drop too low, the effects can range from fatigue and weakness to more serious symptoms. Dr. Chung says this might involve anemia, which is a lack of healthy red blood cells to carry oxygen throughout the body, tingling or numbness in the hands and feet, and problems with balance or memory. If vitamin B12 deficiency persists, you may run the risk of permanent nerve damage.Do GLP-1s Cause a Vitamin B12 Deficiency?TAKING A GLP-1 doesn’t automatically mean you’ll develop a B12 deficiency. It’s more of an indirect effect.“GLP-1 medications are not known to reduce absorption of vitamin B12, unlike metformin, which interferes with the binding of vitamin B12 in the gastrointestinal tract,” explains Dr. Chung. “Instead, nutrient deficiencies with GLP-1 medications arise from a combination of eating less food, eating less dietary variety, delayed gastric emptying, and rapid weight loss.”The common side effects people experience while taking a GLP-1—nausea, vomiting, diarrhea, and constipation—may also contribute to not getting enough vitamins like B12.Do People on a GLP-1 Need a Vitamin B12 Supplement?DOCTORS SAY A vitamin B12 supplement is worth considering for GLP-1 users, but it’s not a requirement.“Several medical societies recommend that GLP-1 users consider supplementation with vitamin D, calcium, B12, and a multivitamin to reduce micronutrient deficiencies, but there is no universal recommendation,” says Dr. Chung.Todd Worley, MD, bariatric surgeon and obesity medicine specialist at Houston Methodist Willowbrook Hospital, says the primary goal is to get enough of this essential nutrient through food.B12 is found in a variety of animal-based foods, including beef, poultry, salmon, tuna, trout, eggs, clams, and dairy products. You can also find a comprehensive list of B12-rich foods here.If a reduced appetite is making you unable to stomach enough food, then it’s time to consider a supplement. Another reason to consider a supplement is if you follow a plant-based or vegan diet.Jacqueline Vernarelli, PhD, nutrition scientist at Sacred Heart University, says that unfortified plant foods aren’t a reliable source of the nutrient since vitamin B12 is primarily in animal-based foods. As a result, she recommends regularly incorporating B12-fortified foods, such as certain breakfast cereals and plant-based milks, to help meet your daily intake.Two Factors That Also Increase the Risk of Vitamin B12 Deficiency AGE AND SOME gastrointestinal conditions can also make it harder for your body to absorb the vitamin. “Conditions that reduce stomach acid increase with age, and stomach acid is needed to release vitamin B12 from protein in food so it can be absorbed,” says Dr. Chung. Guys might start feeling the effects of vitamin B12 deficiency in their 50s.How to Know If Your GLP-1 Is Making You Vitamin B12 DeficientA B12 DEFICIENCY can be difficult to recognize because symptoms often develop gradually and may overlap with other issues. For example, you may attribute fatigue to not eating enough overall when it’s actually because you’re low on B12.Dr. Chung recommends talking with the physician who prescribed your GLP-1 about any changes you’re feeling. They may recommend blood tests to check your B12 levels.If blood tests confirm a B12 deficiency, your doctor may recommend dietary changes or a supplement.Oral B12 supplements in capsule, tablet, or liquid form are often the first line of defense, with a common daily dose of 1,000 micrograms, says Dr. Chung. The reason supplements have larger doses than the recommended daily intake is because the body only absorbs a portion of the vitamin. Intramuscular B12 injections are also an option, but Dr. Worley says those are usually reserved for folks with absorption problems or more significant B12 deficiencies.The right dose and form of B12 supplementation will depend on your individual needs. There’s no one-size-fits-all approach. Above all, Dr. Chung recommends being proactive and planning meals with enough B12 sources and keeping tabs on any signs of potential deficiencies. Losing weight shouldn’t mean sacrificing good health.Andi Breitowich is a freelance writer who covers health, fitness, relationships, beauty, and smart living. She is a graduate of Emory University and Northwestern University's Medill School of Journalism. Her work has appeared in Women's Health, POPSUGAR, Food & Wine, What To Expect, Cosmopolitan, Men's Health, and elsewhere. As a former collegiate pole vaulter, she loves all things fitness and has yet to meet a group workout class she doesn't like.