The Internet is littered with tales of people claiming to have overdosed on vitamin B12, or saying that they suffered various unpleasant symptoms as a result of taking B12 supplements. But the fact is, vitamin B12 is not toxic. If you’re an average, healthy person, you don’t need to worry about negative consequences from taking B12. Vitamin B12 Is Not Toxic Some vitamins are dangerous in large quantities. For example, too much vitamin A will kill you (which is why you should never eat polar bear liver!), and high concentrations of vitamins D, E and K are also harmful. But these vitamins are fat-soluble, so they build up inside your body. Vitamin B12 is not fat-soluble; So any excess B12 in your body is simply excreted out in urine. There have been various scientific studies where test subjects were given extremely high doses of vitamin B12 (often several thousand times the RDA) for extended periods of time (months or years). None of this research suggested that these large quantities of B12 were in any way dangerous – there were no adverse effects.
Hydroxocobalamin (a vitamer of B12) is used to treat cyanide poisoning, most commonly as a result of smoke inhalation. This is generally done by intravenously administering 5mg of B12 (the RDA is 2.4mcg!), and the procedure is sometimes repeated less than an hour afterwards. There would be no reason for anyone to ever take more than this amount of B12, and it doesn’t harm the patients – in fact it often saves their lives. Many national health authorities don’t bother giving an upper limit to the amount of vitamin B12 that is safe to take, because as far as anyone knows, there is no upper limit. The US Food and Nutrition Board is just one of many national organisations that take this approach. The quantities of B12 found in food are tiny compared to what you can find in B12 supplements, so there’s certainly no risk of overdosing from your diet alone. Basically, unless you take more B12 than scientists have ever even considered, you won’t overdose. And even if you did take more, you’d probably still be fine.
Despite not being toxic, it is possible to be allergic to vitamin B12 (or cobalt, a key building block of B12). However, it should be pointed out that vitamin allergies are exceptionally rare. If you have an allergic reaction to a dietary supplement, the chances are that it’s not a vitamin causing the problem, but a different ingredient. Either way, you should seek treatment immediately. For the unfortunate few who are allergic to B12, symptoms may include: Vitamin B12 is known to interact with a number of different medications – you can take a look at our article on medical interactions for more information. You should also be wary of taking B12 supplements if you suffer from any of these conditions: The B12 Deficiency Alternative The point is that you shouldn’t be put off taking B12 supplements by the risk of overdose, toxicity or allergic reactions. Unless you fall into one of the very small and well-defined categories outlined above, you have absolutely nothing to fear.
For the vast majority of people, it would be far better to take more than the RDA of vitamin B12 than to take too little. Not getting enough B12 can lead to vitamin B12 deficiency. This is a serious and unpleasant illness, and everyone should try to minimise their risk of suffering from it. Unfounded fears do nothing but stop people from taking supplements that would probably make them healthier and happier in the long run. If you’d like some advice on choosing a supplement, please take a look at our Choosing a B12 Supplement and Recommended B12 Supplements pages. Alternatively, check out the Amazon products below to see what’s popular with our readers right now! From top to bottom, images are courtesy of cooldesign, imagerymajestic, Mister GC, and jk1991, all at FreeDigitalPhotos.net.After a study was released that reported nearly 40 percent of Americans might be deficient in B12, advocates of vitamin injections seemed to come out of the woodwork! They claim that they can benefit serious conditions, including cancer, macular degeneration, Parkinson's disease, fibromyalgia and depression.
They also say the injections are helpful for preventing illness too. Well-known TV physician, Dr. Oz, went as far as describing them as "cutting edge." The B12 vitamin is an essential micronutrient that affects the development and maintenance of red blood cells, nerve cells, and normal myelination, or the covering, of nerve cells. It also aids in the production of DNA and RNA, and the production of neurotransmitters. So, while B12 injections may be popular, are they something you should really consider? First of all, if you look at closer at the numbers reported by the Framingham Offspring Study that's often cited, you'll see that it actually found 39 percent of people had B12 levels that were in the "low normal" range -- and that's well above the accepted level of deficiency. In reality, the actual numbers of those who suffer from a shortage of B12 are closer to just 1.5 to 15 percent. Most of us get enough through foods like poultry, fish, milk, eggs and fortified products.
Of course, that's not to say that no one should be concerned about low B12 levels. Those who have celiac disease, vegans, vegetarians and people who drink a lot of alcohol, are truly susceptible due to absorption problems and/or diet choices. Please note -- all of the above symptoms are also symptoms of other medical conditions. While there is an established medical role for injectable vitamins like these, it's certainly not an energy-boosting cure-all! The best way to get your B12 is through a variety of healthy foods, including organic, free-range eggs, shellfish, dairy products, wild-caught salmon and other fatty fish like mackerel and tuna. Vitamin infusions are really a marketing creation if anything. They may give you the illusion that you're doing something good for your health, but selling unproven treatments like these without good scientific evidence is really only benefiting those who are making money off people who just want to feel better. If you do fall for the craze, B12 isn't a vitamin that builds up toxicity like some others when taken in excess, which means you're unlikely to experience many negative side effects, other than the damaging effect on your wallet, of course.