Vitamin B12 is linked to everything from properly functioning red blood cells to a healthy nervous system to the creation of new DNA. If you don't get enough of the vitamin, it can cause a wide variety of symptoms and health problems that interfere with your quality of life.
While it's best to get vitamin B12 from foods whenever possible, supplements can help you meet your needs, especially if you have an underlying condition that interferes with the way you absorb the vitamin. While there are some forms of B12 pills and supplements that are generally considered better than others, always work with your doctor to make the best choice for you.
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About Vitamin B12 Deficiency
Vitamin B12 deficiency, a condition in which you don't have enough B12 in your body, is a common nutritional problem, according to a report published in the Journal of Pharmacology and Pharmacotherapeutics in March 2017. Because vitamin B12 is involved in so many functions, a deficiency can produce lots of different symptoms that affect your whole body. Possible symptoms of a B12 deficiency include:
- Soreness of the mouth and tongue
- Decreased appetite
- Weight loss
- Numbness and tingling in the hands and feet
- Poor memory
Although a B12 deficiency can develop simply due to a lack of the vitamin in your diet, certain factors also increase your risk. As you age, your stomach produces less acid, which is necessary for proper digestion and absorption of the vitamin.
Some people also have a condition called pernicious anemia, where their body doesn't make enough of a protein called intrinsic factor, which is vital for B12 absorption. If you don't have enough acid or intrinsic factor, you can't absorb enough B12 from foods or certain supplements.
The Types of B12
The go-to treatment for B12 deficiency is supplementation; but the best B12 supplement for you depends on the cause of your deficiency and its severity. Like many supplements, B12 is available in more than one form.
According to the Linus Pauling Institute at Oregon State University, most supplements contain vitamin B12 in the form of cyanocobalamin, which is a synthetic form that occurs only in trace amounts in human tissues. Other supplements contain natural forms, which include methylcobalamin, adenosylcobalamin, and hydroxycobalamin.
In addition to the different types of vitamin B12 available on the market, there are also different forms of the vitamin. You can purchase vitamin B12 in tablet, capsule or pill form. These are considered oral administrations.
Vitamin B12 is also available as a liquid, which is classified as a sublingual form, because you typically drop it right under your tongue. Nasal sprays and injectable (or intramuscular) vitamin B12 are also available, but B12 injections must be given by your doctor or another qualified health professional.
Read more: Vitamin B12 Benefits and Side Effects
The Best Form of B12
According to a report published in Integrative Medicine in February 2017, the natural forms of B12 (methylcobalamin, adenosylcobalamin, and hydroxycobalamin) are better choices than cyanocobalamin because they're more easily absorbed and used by the body and they tend to be safer. The report also notes that all of these natural forms have similar bioavailability, so any of them is a good choice.
However, keep in mind that while the natural forms of B12 may be the best in theory, the amount your body is able to absorb depends on several personal factors, including your age, genetics and the presence of any digestive problems or infections. The amount you absorb also depends on how much intrinsic factor your body makes.
B12 Pills Versus Injections
According to a report published in BMC Public Health in May 2012, traditional treatment for a vitamin B12 deficiency is with injections of B12 in the form of cyanocobalamin. A typical treatment schedule consists of 1 milligram per day for one week, then 1 milligram per day for one month, then 1 milligram every one to two months or until symptoms resolve and deficiency is reversed. Treatment is set up this way because it's been viewed as the most effective way to correct a deficiency.
However, researchers from a review published in the Cochrane Database of Systematic Reviews in March 2018 set out to test this theory. They looked over all of the evidence and studies on the best B12 supplement and reported that when compared to B12 injections, B12 pills seem to be just as effective as correcting a deficiency.
In some cases, oral B12 was even more effective than intramuscular (or injected) B12 and, as an added bonus, oral forms typically cost less and are easier to take, since you can buy them yourself and don't have to go to the doctor to get them.
But, it's important to note that the researchers reported feeling that evidence quality was on the lower side because they didn't have a lot of previous studies to look over. It's also important to keep in mind that, if you have a condition affecting the amount of intrinsic factor you produce, you need to stick with injectable B12, because your body can't effectively absorb oral versions.
Read more: Is a High Level of Vitamin B12 Bad?
Getting Vitamin B12 From Foods
But Harvard Health points out that if you're able to absorb vitamin B12 properly, your best bet is always to get it from your diet. Foods that come from animal sources are the highest sources of vitamin B12, but some foods are also fortified with synthetic versions of the vitamin. Some vitamin B12 foods include:
- Greek yogurt
- Fortified cereal (synthetic forms added in)
While you can meet your vitamin B12 needs by including a variety of these foods in your diet, Harvard Health states that dairy products, like yogurt, milk and cheese, may contain the most bioavailable (or easily absorbed) forms of the vitamin. Although meat is high in vitamin B12, it's also high in a protein called collagen, which can interfere with the vitamin's absorption. Some of the B12 in meat is also destroyed during cooking.
- Mayo Clinic: "Vitamin B-12"
- Integrative Medicine: "Comparative Bioavailability and Utilization of Particular Forms of B12 Supplements With Potential to Mitigate B12-Related Genetic Polymorphisms"
- National Institutes of Health: Office of Dietary Supplements: "Vitamin B12"
- Harvard Health Publishing: "Vitamin B12 Deficiency Can Be Sneaky, Harmful"
- Oregon State University: Linus Pauling Institute: "Vitamin B12"
- BMC Public Health: "Oral Versus Intramuscular Administration of Vitamin B12 for the Treatment of Patients With Vitamin B12 Deficiency: A Pragmatic, Randomised, Multicentre, Non-Inferiority Clinical Trial Undertaken in the Primary Healthcare Setting"
- Journal of Pharmacology and Pharmacotherapeutics: "Methylcobalamin in Vitamin B12 Deficiency: To Give or Not to Give?"
- Harvard Health Publishing: "Getting Enough Vitamin B12"
- Cochrane Database of Systematic Reviews: "Oral Vitamin B12 Versus Intramuscular Vitamin B12 for Vitamin B12 Deficiency"
- Harvard Health Publishing: "The A List of B12 Foods"
- Harvard T.H. Chan School of Public Health: "Vitamin B12"