Feb 03, 2026
3 min read
The nutrient affects memory, concentration, mental health and more.Here's how to get more out of it.
If you're feeling foggy, sluggish, forgetful, or just plain weird, you may think you need to prioritize sleep or better manage your stress levels.But what if you are really suffering from food shortages?
For a vitamin that may not be in the spotlight for most people, vitamin B-12 plays a surprising role in nervous system function and overall brain health, including supporting memory, concentration, mental health, and keeping brain cells healthy.When B-12 levels get too low, it's one of the first places you can see brain effects, with symptoms like forgetfulness and brain fog.
B-12 deficiency is more common than most people realize, affecting about 6% of Americans under the age of 60 and about 20% of people over the age of 60, although the exact numbers vary.B-12 deficiency can have many different causes, including the foods you eat, medications you take, absorption problems, and your age, with the elderly being more susceptible.
"Vitamin B12 deficiency is one of the few causes of reversible cognitive impairment," said Dr. Majid Fotuhi, a neurologist and associate professor at Johns Hopkins University."Early detection can prevent long-term brain damage and restore mental clarity."
Here's what you need to know about vitamin B-12 and your brain, including why it's so essential, how to get enough, and how a deficiency can occur.
How vitamin B-12 supports a healthy brain
Vitamin B-12 in the brain tried in different ways the same way.Brain gym and brain therapy.
B-12 is also important for the production of neurotransmitters such as dopamine and serotonin, which help regulate mood, focus and motivation.
Another important role of vitamin B-12 is to help the body break down homocysteine, an amino acid that can build up when B-12 levels are low.Increased homocysteine has been linked to increased oxidative stress and poor blood vessel function, which can increase cognitive decline.
"Together, these roles make B-12 essential for sharp thinking, memory and mental energy," Fotohy said.
When B-12 levels are low, nerve signals slow down or misfire, damaging brain cells.Over time, B-12 deficiency can cause confusion, balance problems, slow thinking and difficulty concentrating.Some studies have also linked high levels of homocysteine to cognitive decline and neurodegenerative diseases such as Alzheimer's disease and other forms of dementia.
Signs You May Be Dealing with a Decrease in B-12
If you are low in vitamin B-12, you may experience symptoms throughout your body.These include anemia, numbness or tingling in the hands and feet, palpitations, memory problems, difficulty concentrating, balance problems, and fatigue and weakness due to mood changes such as irritability, depression, and apathy.
Anemia is common when you have a B-12 deficiency, but you can also experience neurological symptoms when your B-12 levels are low, Dr.
Symptoms of B-12 deficiency may develop slowly and may not be noticeable at first, but may worsen over time.
“Symptoms of vitamin B12 deficiency may not appear until vitamin B12 levels in the body drop significantly,” says registered dietitian Patricia Coleza."Serum vitamin B12 levels of 200 pg/mL or lower will confirm deficiency. However, measurement of homocysteine and methylmalonic acid can also provide insight into how vitamin B12 works."
In a recent study, some older adults showed signs of cognitive and neurological problems even though B12 levels were technically in the normal range but on the low end.
If you're worried about your memory or experiencing fatigue or weakness, have problems with balance, or are dealing with any of the symptoms we've mentioned, talking to a doctor and getting your B-12 levels tested can be an important step in protecting your brain health.
"Vitamin B12 deficiency is common, poorly understood, and easy to diagnose and treat," said Dr. Joel Salinas, clinical professor in the department of neurology at New York University Grossman School of Medicine."Because neurologic and emotional problems can mimic more serious brain problems, these are always screened for in tests for cognitive decline."
Many factors can put you at risk of B-12 deficiency
Vitamin B-12 depends on the production of red blood cells.In order for your body to get enough vitamin B-12, you must eat foods that contain B-12, and your body must absorb the B-12 correctly.An intrinsic factor called protein released by stomach cells aids in the absorption of B-12.Your body cannot make vitamin B-12 on its own, so you may be at risk for failure if you don't eat enough fatty foods containing B-12, take B-12 supplements, or have trouble absorbing it for any reason.
"Vegetarians and vegetarians are at risk of B-12 deficiency, given that vitamin B-12 is found primarily in animal sources," Kolesa said.
Gastrointestinal problems that affect B-12 absorption, such as Crohn's disease or celiac disease, pernicious anemia, previous gastric or bariatric surgery, or heavy alcohol consumption can put you at risk for low B-12 levels.The elderly are also at increased risk of B-12 deficiency, as absorption often decreases with age.
People who take metformin and prescription medications like skin creams for a long time can also develop B-12 deficiency and should be monitored, Salinas said.
What To Do If You Have Low B-12
Eating a diet rich in B-12 can help maintain healthy levels.Some good food sources include fish, meat, eggs, milk, nutritional yeast, and fortified breakfast cereals.But people who are deficient may need to take B-12 supplements by mouth or by injection.Your primary care doctor can test your levels through a basic blood panel to determine if you are deficient or low in vitamin B-12.
"Oral B12 supplements are effective for most patients, while the injectable form is used in more severe cases," Salinas said."A blood test is the most reliable way to determine if the nutritional intake is sufficient."
Testing is an important way to catch B-12 deficiency before it progresses to the point where it is irreversible.When B-12 deficiency is treated promptly, memory loss, mood changes, and concentration problems can be completely resolved.But without treatment, permanent memory loss can occur, Copeland said.
"In its more severe form, this can progress to frank dementia with behavioral symptoms, including psychosis," he said."This underscores the importance of testing vitamin B-12 levels in anyone with unexplained memory loss."
This article originally appeared on The Huffington Post.
