Brain Fog Is the Worst—These Vitamins Can Help

Your lack of focus could be the effect of a vitamin deficiency.

30-Second Takeaway

  • Brain fog is the casual term to describe difficulties with cognitive function.
  • Brain fog may be the result of neuroinflammation—or inflammation of the brain.
  • A deficiency in some vitamins or nutrients may contribute to brain fog, and supplementing could help to alleviate symptoms.

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If you have difficulty concentrating, your surroundings aren’t always clear, and a normal work day feels like trudging through quicksand—but you don’t understand why. Nothing has really changed—your diet is consistent, your sleep isn’t suffering, you’re not drinking or smoking—yet you’re not as sharp as you once were. So it must all be in your head, right? Eh, not quite.

The culprit could be brain fog.

But it’s not as ominous as it sounds. Your sudden feelings of discombobulation may simply be attributed to a vitamin deficiency. If that’s the case, there are supplements that can help restore peace in your head.

What Is Brain Fog?

The name is pretty spot-on. “Brain fog is a casual term used to describe cognitive difficulties (1),” explains Imashi Fernando, MS, RDN, a member of Hone’s advisory board. “This could include forgetfulness or difficulty focusing, thinking, and communicating (2). It can also include difficulty with working efficiently or being productive, as well as loss of short term and/or long term memory,” she says (3).

What Causes Brain Fog?

Although it’s not yet well understood, physiologically, brain fog may be the result of neuroinflammation—or inflammation of the brain, explains Fernando. Its triggers are also the subject of ongoing research, but they may include several different factors like fatigue, stress, burnout, depression, lack of sleep, dehydration, standing for too long, certain medical conditions, medications, hormone imbalances, poor nutrition, food sensitivities, or even long COVID (4).

What Vitamin Deficiency Causes Brain Fog?

A deficiency in some vitamins or nutrients may contribute to brain fog. “People with multiple allergies or dietary restrictions may not have a nutritionally balanced diet, therefore are more likely to be deficient in some vitamins or nutrients,” says Fernando. Fernando says you could be low in essential B vitamins (B12, B6, and folate specifically), vitamin D, omega-3 fatty acids, magnesium, and antioxidants like vitamin C, vitamin E, and polyphenols (plant compounds found in fruit, vegetables, and certain drinks), all of which protect the body from oxidative stress (5) and inflammation.

Iron-deficiency anemia can cause fatigue, which may promote or lead to brain fog, Fernando adds. 

In this case, your doctor may recommend an iron supplement.

What Supplements Help With Brain Fog? 

If you’re lacking in the vitamins mentioned above—which should be confirmed by blood work performed by a doctor—you may benefit from incorporating the below supplements into your wellness regimen. 

Vitamin B

Fernando says supplementation with B6, B9 (aka folate), and B12 vitamins have been shown to have positive effects on memory performance and cognition. A study published in 2021 in The Journal of Nutrition, Health & Aging found that a B12 deficiency in the male participants was associated with poorer memory and attention (6). A study published in 2020 found that vitamin B12 supplementation among those with a B12 deficiency led to reports of improvement in symptoms of cognitive impairment in 84 percent of the patients (7). Therefore, decreased brain fog.

Ongoing research suggests that folate and other B vitamins may also have the potential to help slow down brain atrophy in older adults (in brain tissue, atrophy describes a loss of neurons and the connections between them) (8).

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B12 Benefits

Vitamin D

There’s a reason soaking up the sun puts you in a good mood. The body makes vitamin D when you absorb UV rays through your skin (9). But it’s also found in certain foods—mainly fish and fortified dairy (10). A vitamin D deficiency has been linked to depression (11), Alzheimer’s disease, and dementia (12), explains Fernando. “It is also involved in the development and function of brain tissue,” she adds.  

A study published in 2014 found vitamin D supplements enhanced brain health and cognition in rats such that they could perform a complex memory task (13). Additionally, a 2020 meta-analysis of 25 studies found vitamin D had reduced negative emotions such as depression and anxiety in certain groups of participants (14).  Depression is being studied as a possible trigger for brain fog. 

Vitamin D deficiency is very common—according to the Cleveland Clinic about 1 billion people worldwide have vitamin D deficiency, and that includes about 35 percent of adults in the United States, so chances are you likely have low levels of vitamin D. 

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Vitamins & Supplements

Omega-3 fatty acids 

Omega-3 fatty acids, which are naturally found in fish and plant oils like soy and flaxseed (15)—play an important role in brain function and development (16). So, if you’re low in them, it would come as no surprise that you’re feeling out of sorts. “Low omega-3 levels have been linked with depression,” Fernando says. Additionally, a study published in 2014 in Human Psychopharmacology found that supplementing with the omega-3 fatty acid EPA improved participants’ cognitive performance (17). A study published in 2013 found that participants with diets low in Docosahexaenoic acid (DHA), a specific type of omega-3 fatty acid, saw improvements in aspects of episodic and working memory after taking 1.16 grams of DHA every day for six months (18).

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If you aren’t eating enough greens, nuts, seeds, beans, and whole grains, your magnesium tank could be drained, which could be linked to brain fog, given that magnesium deficiencies have been associated with increased susceptibility to stress  (19), as well as mild cognitive impairment and dementia (20). Preliminary studies in animals suggest that magnesium may play a role in learning and memory (21), and a 2020 review of 32 studies found magnesium supplements were beneficial to some extent in 29 of the studies, which worked with participants suffering from common mental health conditions including depression, anxiety, attention deficit hyperactivity disorder (ADHD), and more (22).

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Antioxidants (vitamin C, vitamin E, and polyphenols)

Antioxidants are all about protection from free radicals. Taking them in supplement form may help to reduce brain fog (23). “These work to counteract the effects of pro-oxidant free radicals which cause cellular damage and increase inflammation,” explains Fernando. Vitamins C and E are mainstream go-tos, says Fernando. Vitamin C contributes to a robust immune system, sharp eyesight, and strong bones. But she adds that polyphenols like flavonoids (found in green tea) and resveratrol (found in red wine) may also be great defenders. “Increased intake of polyphenols—both via diet and supplements—have been shown to improve working memory, attention, and processing speed (24),” she adds. 

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The Bottom Line

Though there are many reasons you could be suffering from brain fog, a vitamin or nutrient deficiency could be to blame. If you’re feeling extra forgetful, or have ongoing difficulty focusing, thinking, and communicating, talk to your doctor about testing for potential deficiencies and supplementing accordingly.

  1. Kverno K. (2021) Brain Fog: A Bit of Clarity Regarding Etiology, Prognosis, and Treatment.
  2. Ross, A. J., et al. (2013) What is brain fog? An evaluation of the symptom in postural tachycardia syndrome. 
  3. Theoharides, T. C., et al. (2015) Brain “fog,” inflammation and obesity: key aspects of neuropsychiatric disorders improved by luteolin.
  4. Fong, Tamara, MD PhD. (2022) Brain Fog: Memory and Attention After COVID-19. 
  5. Betteridge D. J. (2000) What is oxidative stress?. 
  6. Nalder, L., et al. (2021) Vitamin B12 and Folate Status in Cognitively Healthy Older Adults and Associations with Cognitive Performance.
  7. Jatoi, S., et al. (2020) Low Vitamin B12 Levels: An Underestimated Cause Of Minimal Cognitive Impairment And Dementia.
  8. McGarel, C., et al. (2015) Emerging roles for folate and related B-vitamins in brain health across the lifecycle. 
  9. Wacker, M., & Holick, M. F. (2013) Sunlight and Vitamin D: A global perspective for health.
  10. Harvard T.H. Chan School of Public Health. (2023) Vitamin D.
  11. Anglin, R. E., et al. (2013) Vitamin D deficiency and depression in adults: systematic review and meta-analysis.
  12. Soni, M., et al. (2012) Vitamin D and cognitive function.
  13. Latimer, Caitlin S., (2014) Vitamin D prevents cognitive decline and enhances hippocampal synaptic function in aging rats.
  14. Cheng, Y. C., et al. (2020) The effect of vitamin D supplement on negative emotions: A systematic review and meta-analysis.
  15. Office of Dietary Supplements (2022) Omega-3 Fatty Acids
  16. DiNicolantonio, J. J., et al. (2020) The Importance of Marine Omega-3s for Brain Development and the Prevention and Treatment of Behavior, Mood, and Other Brain Disorders.
  17. Bauer, I., et al. (2014) Omega-3 supplementation improves cognition and modifies brain activation in young adults.
  18. Stonehouse, W., et al. (2013) DHA supplementation improved both memory and reaction time in healthy young adults: a randomized controlled trial.
  19. Pickering, G., et al. (2020) Magnesium Status and Stress: The Vicious Circle Concept Revisited.
  20. Lo, K., et al. (2019) Relations of magnesium intake to cognitive impairment and dementia among participants in the Women’s Health Initiative Memory Study: a prospective cohort study.
  21. Hoane, R. M., (2011) The role of magnesium therapy in learning and memory.
  22. Botturi, A., et al. (2020) The Role and the Effect of Magnesium in Mental Disorders: A Systematic Review.
  23. Lee, K. H., et al. (2020) Neuroprotective Effect of Antioxidants in the Brain.
  24. Godos, J., et al. (2021) Dietary Antioxidants and Brain Health: Focus on Cognitive and Affective Disorders.