Metformin (brand names Glucophage, Glucophage XR, Fortamet, Riomet, Glumetza, and others) is a popular and highly effective oral diabetes drug used to help manage Type 2 diabetes. This drug works by lowering the amount of glucose made by the liver and by making the body’s cells more sensitive to insulin. Metformin also has some other beneficial effects in that it may help lower blood lipid, or fat, levels (cholesterol and triglycerides) and can, in some people, promote a small amount of weight loss. Metformin can be used with other diabetes pills and with insulin. Side effects of taking metformin are relatively rare, the most common being bloating, nausea, and diarrhea, all of which are temporary. Some people shouldn’t take metformin, including people with kidney disease, liver disease, or congestive heart failure, for example, because of an increased risk of a potentially fatal condition called lactic acidosis. In recent years, there’s been some concern over the risk of vitamin B12 deficiency in people who take metformin.
Vitamin B12 (also known as cyanocobalamin or cobalamin) plays many important roles in the body, such as keeping your blood cells and nervous system in tip top shape. There’s also some evidence that vitamin B12 may help prevent heart disease and possibly even Alzheimer disease (the jury is still out on this one). This vitamin is found primarily in animal foods, such as beef, seafood, eggs, and dairy products, which is why some vegetarians are at risk for a B12 deficiency. Elderly people are often at risk for deficiency as well, due to problems with absorption from the gastrointestinal tract. Symptoms of B12 deficiency include certain types of anemia, neuropathy, memory loss, confusion, and even dementia. So, why would taking metformin possibly put you at risk for a B12 deficiency? According to some studies, between 10% and 30% of people who take metformin on a regular basis have some evidence of decreased B12 absorption. Researchers aren’t quite sure why this happens. In a study recently published in the October 9 issue of the journal Archives of Internal Medicine,155 Chinese people with Type 2 diabetes taking metformin were identified as having a B12 deficiency, regardless of factors such as age or body weight.
The study found that the longer a person had been taking metformin and the higher his daily dose of the drug, the greater his risk of developing B12 deficiency. The authors of the study advocate consideration of vitamin B12 deficiency screening for people who take metformin. While this screening isn’t routine, it’s worth it to have a talk with your health-care provider to see if you’re at risk for deficiency, especially if you’ve been taking metformin for several years or take a high dose. Also, if you have any of the symptoms of B12 deficiency mentioned above, particularly those related to neuropathy (numbness, pain, or tingling in your hands or feet), be sure to let your physician know. He or she can check the level of vitamin B12 in your blood. Vitamin B12 deficiency can be treated with either oral, injected, or inhaled forms of B12. Some people, such as strict vegetarians or the elderly, may need to take supplements or receive injections on a regular basis. B12 is found in most multivitamin supplements, so it doesn’t hurt to take a multivitamin as a safeguard.
However, avoid taking a B12 supplement unless your doctor has prescribed them. Too much vitamin B12 may be harmful, and B12 can also interact with certain medicines. Always let your health-care team know about all medicines and supplements that you’re taking at each visit.Vitamins are vital, and we should always take more, right? Everyone needs to get a minimum amount of vitamin B12. But taking too much vitamin B12 can make your acne worse, and even trigger breakouts when you have clear skin. On the other hand, certain acne medications can cause a deficiency of vitamin B12 that leads to pernicious anemia, without administration of additional B12. Vitamin B12 has the most complex chemical structure of all the vitamins. It consists of an organic molecule organized around a central atom of cobalt. There are three forms of B12 the body can use, all of them known as cobalamin, after the cobalt in the vitamin. Cyanocobalamin is the form of B12 found in supplements. It is used in supplements because it is easy to make, and the body can easily convert it into the methylcobalamin and 5-deoxyadenosyl cobalamin it actually uses in enzymes.
One of the enzymes the body makes with vitamin B12 is involved in detoxifying a substance called homocysteine. The other of the enzymes of the body makes with vitamin B12 is essential for the production of hemoglobin, the iron-rich protein that the blood uses to transport oxygen. Without enough vitamin B12, it is possible to develop a form of anemia known as pernicious anemia, in which the body has enough iron but cannot use it to make hemoglobin for red blood cells. Some people who use retinoid drugs for acne need B12 injections to prevent high homocysteine. Retinoid drugs applied directly to the skin, such as topical tretinoin and Renova, don’t have this effect. Retinoid drugs taken as a pill, however, can interfere with the action of an enzyme called cystathionine-beta-synthase. This enzyme converts homocysteine, which can inflame arteries, into a harmless form. Taking more B12 compensates for the poor performance of the enzyme and helps prevent cardiovascular complications.
Just one injection usually is enough. Many people who get vitamin B12 injections for pernicious anemia, on the other hand, break out in a very particular kind of acne. Injections of vitamin B12 don’t cause one or two pimples to break out. Injections of vitamin B12 often cause massive numbers of identical pimples to break out all over the face. It is easy to identify this kind of acne as due to vitamin injections because all the pimples will look the same. If you need vitamin B12 injections, however, you are almost certainly taking them to correct a condition that is even more serious than acne. The good news about vitamin B12 excess and acne is that the blemishes go away about two weeks after the last B12 injection, even if you do not do anything to treat them. If you have brown, black, or Asian skin, you will probably get a better long-term result if you do nothing for acne caused by B12 injections, because most acne treatments for blemishes that are this extensive will leave brown spotting on the skin.
The amount of vitamin B12 you get in a “complete B” vitamin supplement is not enough to make your skin out. Neither is it enough to treat pernicious anemia (that requires injections), but it will help prevent both high homocysteine and pernicious anemia. If you are not using any oral medications for treating acne, you do not need extra B12 for fighting acne. Nonetheless, there are many situations in which taking supplemental vitamin B12 is a very good idea. If you take a proton pump inhibitor such as lansoprazole (Prevacid) or omeprazole (Prilosec), the drugs may reduce the amount of acid in your stomach to the point it cannot release vitamin B12 from food, although there is enough stomach acid to dissolve vitamin B12 from supplements. Deficiency conditions usually take several years to develop. The H2-receptor antagonists such as cimetidine (Tagamet), famotidine (Pepsid), and ranitidine (Zantac) can also interfere with the release of vitamin B12 from food, but their effects are not as severe.
The diabetes medication metformin (Glucophage, Glucophage XR) binds vitamin B12 to calcium. If you use metformin, as tens of millions of type 2 diabetics do every day, then taking your vitamin B12 supplement within two hours before or after eating dairy products will not do you any good. And taking the antibiotic Neomycin by mouth can also interfere with the absorption of vitamin B12. There is no evidence that creams and lotions or any other kind of topical skin care products containing vitamin B12 have any special value in treating acne. There is a little evidence that vitamin B12 creams may help psoriasis. There is also a product that contains an anti-irritant known as licochalcone with vitamin B12 for treating eczema in children, although the product is currently only available in Thailand. A study done about 30 years ago found that vitamin B12 is involved in the immune system’s response to staph infections, but no follow-up research confirmed the initial observations. On the other hand, there is no evidence that creams or lotions or any other kind of topical skin care products containing vitamin B12 make acne worse.