- Some research shows links between a vitamin B12 deficiency and anxiety.
- Vitamin B12 is important for red blood cell production, nerve functioning, and DNA production, all of which are linked to mood.
- Research hasn’t proven that supplementing with vitamin B12 improves anxiety, but if you are deficient, talk to your doctor about supplementation.
Anxiety can be isolating, but if you’ve been dealing with spiraling thoughts, constant stress, or a feeling of impending dread you’re not alone: One in six Americans reported a recent bout of anxiety in 2019 (1). During the first year of the pandemic, that number leaped to more than one in three. There’s lots of ways to tackle anxiety, including a veritable smorgasbord of supplements, including vitamin B12. But does B12 help with anxiety?
Several studies have shown that people experiencing anxiety have lower vitamin B12 levels. One 2000 study found that men with vitamin B12 deficiency who recently lost a loved one reported higher levels of anxiety and depression (2). Another found that people who regularly eat yeast-based spreads like Vegemite—which are often fortified with B12—were less anxious than those who don’t eat them (3). And in a 2017 study, more than half of the participants with depression and anxiety had a vitamin B12 deficiency, even though their average age was under 60, a population that usually has only a 4 percent rate of deficiency (4).
But while those studies showed links between B12 and anxiety, they haven’t yet proven that supplementation improves anxiety.
Here’s what we know so far—and how to evaluate if your body (and brain) could benefit from a vitamin B12 boost.
B12 and Anxiety: The Basics
- Some studies have found people experiencing anxiety have lower levels of vitamin B12, and that people with anxiety and depression at more likely to have a vitamin B12 deficiency.
How Might Vitamin B12 Affect Anxiety?
Otherwise known as cobalamin, vitamin B12 plays an indispensable role in many bodily functions, including the formation of red blood cells, nerve function, and DNA production (5). All of these are linked to mood.
Vitamin B12—which is found in a wide variety of animal foods like fish, meat, poultry, and dairy— contributes to the production of myelin, the fatty substance that insulates neurons. This coating enables your nerves to communicate with each other.
If your B12 is lacking, your mental processing speed can slow down, says Lina Begdache, Ph.D., an assistant professor at Binghamton University, who studies the link between diet and mental health.
A sluggish brain may struggle to calm itself when anxiety strikes. “The communication is slower,” explains Begdache. “So people may not be able to control that emotion. It becomes a vicious cycle. One thought would trigger more anxiety, and more anxiety would trigger more negative thoughts.”
Vitamin B12 also helps turn an unusable amino acid, called homocysteine, into a usable compound. Without adequate B12, homocysteine levels rise.
“Homocysteine is very prone to oxidation,” the same process that occurs when metal rusts, says Begdache. “So it actually destroys our proteins, our cells. It destroys brain chemicals.”
In a study of 6,000 people in the Journal of Nutrition, elevated homocysteine wasn’t linked to anxiety, but it was correlated with depression (6).
According to the Anxiety and Depression Association of America, nearly 50 percent of people diagnosed with depression are also diagnosed with an anxiety disorder (7). “Anxiety is a prerequisite of depression,” says Teodoro Bottiglieri, Ph.D., co-author of Homocysteine: Related Vitamins and Neuropsychiatric Disorders. “Before you get to the point of clinical depression, there’s typically—not always, but in many cases—a period where [people] are very anxious.”
DNA and Red Blood Cell Production
Vitamin B12 is needed to create red blood cells, which deliver oxygen to the brain. That means B12 deficiency can lead to a decline in your healthy red blood cell count—which equals lower levels of oxygen being delivered to your brain. B12 is also needed for DNA production. If your body isn’t able to make enough high-quality DNA, new cells might lack the genetic material they need, says Begdache. “When [you] don’t have enough of the precursors to produce the brain chemicals needed”—including mood-regulating dopamine and serotonin—“then [you may have] heightened anxiety,” says Begdache.
B12 and Mood
- Vitamin B12 is necessary for several important functions in your body that have been linked to mood, including the formation of DNA, nerve function, and red blood cells.
- If your B12 levels are low, your body may not be able to carry out these key processes well.
Can Supplementing With Vitamin B12 Ease Anxiety?
Despite the clear role of B12 in our brains, conclusive research on supplementation to treat anxiety is lacking. In an Australian study, for example, stressed-out workers given a vitamin B-complex supplement didn’t report any changes in anxiety after three months (8). In fact, they fared no better than those who took a placebo. But the supplement only contained 30 micrograms of vitamin B12—a dose much lower than is typically given therapeutically—and the researchers didn’t assess whether the study participants were deficient before starting supplementation.
A 2019 meta-analysis (9) concluded that taking B vitamins can help reduce stress, but have no beneficial effect on anxiety. (Stress is typically triggered by something outside yourself, while anxiety persists even when there’s no external stressor.) But take a peek at the study population, and you’ll see that, on average when measured, the participants’ B12 levels were adequate and that those with mood disorders weren’t included.
In other words: studies haven’t shown that supplementing with vitamin B12 will calm anxiety. But one thing that is clear is that severe vitamin B12 deficiency can cause neuropsychiatric symptoms—including anxiety.
What Are The Symptoms of Low B12 Levels?
Some of the most common symptoms of low vitamin B12 include:
- Shortness of breath
- Loss of appetite or weight loss
- Heart palpitations
- Pale skin
- Sore tongue
- Mouth ulcers
Severe, prolonged vitamin B12 deficiency can lead to neurological symptoms including:
- An inability to feel vibrations (particularly in your legs)
- Difficulty balancing
- Tingling hands, feet, and limbs
- Cognitive and psychological changes
You won’t necessarily experience the minor symptoms first. “[People] may not even know they’re B12 deficient until they start manifesting some more severe symptoms, which may initially present as just agitation and anxiety,” before progressing into more serious psychiatric disorders, says Bottiglieri.
And not all patients have the same set of symptoms—some deficient folks don’t have any symptoms at all.
“You could have somebody who has a B12 deficiency of approximately the same level, but may present with hematological problems and not neurological—or vice versa,” Bottiglieri says. “But ultimately if you leave them untreated, they will develop both.”
Vitamin B12 deficiency can cause neuropsychiatric symptoms—including anxiety
How Can I Find Out if I am B12 Deficient?
Unfortunately, determining whether you’re getting enough of the nutrient isn’t totally straightforward.
“The sensitivity of measuring B12 in the blood is not great,” says Ralph Green, M.D., a professor of medicine at U.C. Davis.
Complicating matters is that the amount of vitamin B12 in your blood doesn’t reflect how much is in your tissues. “You may test for B12 in the blood, and you have enough B12,” says Begdache. “But how are your cells—your brain—using B12? That may be the issue.”
If you have a genetic variation that affects the proteins delivering vitamin B12 to your cells or the receptors enabling it to enter, you may not effectively utilize the micronutrient, even if your blood levels are adequate. “It’s a very complex process, and that may explain the differences in research results,” says Begdache. Studies can’t always capture the intricacies of how vitamin B12 is being used in our bodies—no matter what your blood levels of the vitamin seem to say.
Your move: If you’re experiencing symptoms of low vitamin B12, ask your doctor for a blood test that measures total vitamin B12, along with the following compounds: methylmalonic acid (MMA) and homocysteine. Both compounds are elevated when you’re vitamin B12 deficient and are more sensitive predictors of deficiency than your serum level of the vitamin.
“If you have an elevation in both homocysteine and MMA, we’re 95 percent sure that it’s a B12 problem,” says Bottiglieri. (Homocysteine is also elevated in folate deficiency, so if you’re only going to test one, opt for MMA, which only increases with vitamin B12 deficiency.)
Another test to ask your doctor about: holotranscobalamin, sometimes called active vitamin B12. This test assesses the B12 that’s available for your cells to use, so it may provide a better sense of how well your body is utilizing the vitamin, says Begdache.
Testing for B12 Deficiencies
- Blood tests can assess whether you are deficient in vitamin B12.
- If you have symptoms of low B12, you may want to ask your physician about testing your levels of MMA and homocysteine, compounds that are elevated when vitamin B12 levels are low.
I Have Anxiety. Should I Test My B12 Levels?
Anxiety alone doesn’t mean you have low B12 (although it could feasibly be your only symptom). But if you have an elevated risk of deficiency, it’s worth investigating with the blood tests mentioned above.
At-risk groups include vegans and vegetarians (since most dietary sources of vitamin B12 are animal products), or people whose bodies may not absorb enough of the vitamin due to:
- Age (60+)
- Gastrointestinal diseases (like Crohn’s, ulcerative colitis, or celiac disease)
- Pernicious anemia
- Bariatric surgery
- Long term use of proton-pump inhibitors or H2 blockers
“If people in these groups have noticed a change in their mood recently, they may want to investigate B12,” says Begdache.
Should I Take Vitamin B12 for My Anxiety?
If a test shows that you’re deficient, dose up on vitamin B12 regardless of your anxiety’s origin, since some of the neurological effects can be irreversible. If your mood improves, don’t discontinue any prescription medications, like anti-anxiety drugs or antidepressants, without consulting your doctor.
If you’re not short on the stuff (and have none of the conditions that predispose you to deficiency), there’s no strong evidence to suggest that vitamin B12 supplementation will ease your anxiety.
Low B12: Are You at Risk?
People more at risk for vitamin B12 deficiencies include those over the age of 60, those with G.I. diseases or pernicious anemia, people who have had bariatric surgery, and people who have used PPI medications for long periods of time.
How Much B12 Should You Take?
If you’re vitamin B12 deficient due to low dietary intake (e.g. you’re vegan or vegetarian), you can replenish your stores with a daily oral dose based on your doctor’s recommendation.
If you’re unable to adequately absorb B12, due to age or an underlying health condition, your best bet is B12 injections, which bypass your gut and send the micronutrient directly into your muscle.
What Are The Side Effects of Taking B12?
While there are no known serious side effects from vitamin B12 supplementation, high doses may lead to:
- Loss of appetite
- Tingling in the hands and feet
Vitamin B12 shots can result in injection-site soreness, redness, and swelling.
The Bottom Line