What’s the Connection Between Vitamin B12 and Psoriasis?

By Kelly Bryant
Reviewed by Allison Truong, M.D.
July 08, 2021

For decades, researchers have studied a link between vitamin B12 deficiency and psoriasis, leaving many people wondering whether they should take a vitamin B12 supplement (also known as cyanocobalamin) to help their condition. The short answer is: You should take the supplement only if you’re actually deficient in vitamin B12. There’s no extra benefit from taking more vitamin B12 than is necessary. Still, we decided to dig a little deeper.

Here, Elizabeth DeRobertis, a New York-based registered dietitian, answers our questions related to vitamin B12. She strongly encourages anyone to consult with their doctor before beginning any vitamin supplementation. Here’s what else she had to say.

What does vitamin B12 actually do for our bodies?

Vitamin B12 is required for the normal functioning of the brain and the nervous system. The metabolism of every cell in the body depends on vitamin B12, as it plays a part in the synthesis of fatty acids and energy production. Vitamin B12 enables the release of energy by helping the human body absorb folic acid.

The human body produces millions of red blood cells every minute. These cells cannot multiply properly without vitamin B12. The production of red blood cells reduces if vitamin B12 levels are too low, and a person can develop anemia if they’re vitamin B12 deficient.

Who is at risk for vitamin B12 deficiency?

Conditions that may be associated with vitamin B12 deficiency may include someone eating a strict vegan diet. Also, people with Crohn’s disease, people who had bariatric surgery, or people with other gastrointestinal disease could have decreased absorption of vitamin B12. Certain rare genetic disorders or autoimmune diseases may also cause vitamin B12 deficiency.

Interestingly, some medications can also decrease the absorption of vitamin B12. These may include colchicine, metformin, proton pump inhibitors, some antibiotics, anti-seizure medications (including phenobarbital, phenytoin, and primidone), and histamine-2-receptor blockers (cimetidine/famotidine). If you’re taking any medications, you may want to run it past your doctor to see if you might need to get your levels checked.

Why might someone with psoriasis want to take a vitamin B12 supplement?

There’s research dating back to the 1950s looking for a link between vitamin B12 and psoriasis. A number of factors suggest there is a link between vitamin B12 deficiency and flare-ups of psoriasis symptoms.

One study found that people with psoriasis have higher homocysteine, which is an amino acid produced by the body that can be a sign of vitamin B12 deficiency. Essentially, the findings concluded that homocysteine may advance the inflammatory process involved in the development of psoriasis. Higher levels of homocysteine in the blood have also been linked to more cardiovascular events.

Another study found that the vitamin B12 level in the blood is lower in psoriatic than non-psoriatic skin, and active lesions also have lower levels of the vitamin than healed lesions.

Is there a standard dosage of vitamin B12 to take daily? How much is considered too much?

The National Institutes of Health (NIH) recommend that teens and adults over the age of 14 years consume 2.4 micrograms (mcg) of vitamin B12 a day. Pregnant women should consume 2.6 mcg, and lactating women 2.8 mcg.

Vitamin B12 is water soluble, so excessive intake hasn’t been found to be toxic, but it’s best to always speak with your physician before starting any supplementation. Interestingly, at least one study suggests that vitamin B12 may be more beneficial topically than it is orally.

What foods are sources of vitamin B12?

Vitamin B12 is found only in animal foods. These include fish, shellfish, dairy products, organ meats (like liver and kidney), eggs, beef, and pork.

How can someone find out if they’re vitamin B12 deficient?

A doctor can test vitamin B12 level as part of a regular blood test in the office. Vitamin B12 is not a routine laboratory test in an annual exam unless the person is on certain restricting diets (like a vegan diet) or have signs or symptoms of vitamin B12 deficiency, such as anemia (low red blood cells) or acute neuropsychiatric changes, such as confusion.

If someone is not deficient, taking the vitamin probably won’t help. But if they’re deficient, then supplementing makes sense. If someone is significantly deficient in vitamin B12, they’ll likely need to start with injections to boost their level up, and then can continue taking oral supplements to maintain that healthy level.

Are there any potential negative side effects of taking a B12 vitamin supplement?

There are unlikely to be any side effects of taking vitamin B12. Similar to vitamin B7 (biotin), taking supplements may affect certain laboratory tests producing false results, so always inform your doctor about any supplements you’re taking.

Remember: Vitamin B12 supplementation is only for people who have a proven deficiency based on lab testing. More randomized clinical trials need to be done to further understand vitamin B12’s impact on psoriasis. It’s best to continue your doctor recommended or prescribed treatments, and any decision on additional vitamins or supplements should be discussed with your healthcare provider.

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