Vitamins for the brain, which ones matter and who needs them
B12, folate, iodine, iron, omega-3 and more, what UK claims allow, what memory trials found, and who might actually be low.
- Written by
- George M.
- Last updated
- Reading time
- 9 min read
Overview
Vitamin B12, folate, B6, iodine, iron and zinc have UK claims for normal brain or psychological function, and DHA for normal brain function. They matter most if you're short. In people who already get enough, trials of vitamins for memory have mostly found little or no effect.
Key points
- B12, folate, B6, iodine, iron, zinc, DHA and magnesium have UK claims linked to the brain.
- Trials of B vitamins in people who aren't low mostly found little or no effect on thinking.
- Low vitamin B12 can cause memory problems, and a GP can check with a blood test.
- Vegan diets need fortified foods or supplements for B12 and iodine, says the NHS.
- Everyone should consider vitamin D in autumn and winter, though it has no brain claim.
Open your fridge. Look for eggs, milk, cheese, fish and fortified cereal. Those foods are good sources of vitamin B12 and iodine, two nutrients your brain and nerves need, so check them before the supplement aisle [1][2][3].
The vitamins and minerals with UK-authorised claims for the brain include vitamin B12, folate, vitamin B6 and other B vitamins, vitamin C, iodine, iron and zinc, plus the omega-3 fat DHA [3]. They support normal function. In people who already get enough, trials of vitamins for memory and thinking have mostly found little or no effect [4].
Which vitamins are good for the brain?
Start with the official list. In the UK, a health claim is allowed only after the evidence has been checked, and these are the ones that mention the mind, brain or nerves [3].
| Nutrient | Authorised claim | Good food sources |
|---|---|---|
| Vitamin B12 | Normal psychological function and nervous system | Meat, fish, milk, cheese, eggs, fortified cereals [1] |
| Folate | Normal psychological function | Broccoli, sprouts, leafy greens, peas, chickpeas [1] |
| Vitamin B6 | Normal psychological function and nervous system | Pork, poultry, peanuts, oats, bananas, milk [1] |
| Iodine | Normal cognitive function | Milk and dairy, eggs, sea fish, shellfish [2] |
| Iron | Normal cognitive function | Red meat, beans, nuts, dried fruit, fortified cereals [5] |
| Zinc | Normal cognitive function | Meat, shellfish, cheese, bread [6] |
| DHA (omega-3) | Normal brain function, from 250 mg a day | Oily fish such as salmon and sardines [7] |
| Magnesium | Normal psychological function and nervous system | Spinach, nuts, wholemeal bread [6] |
Thiamin, niacin, biotin and vitamin C also carry psychological function or nervous system claims, and pantothenic acid can be said to support normal mental performance. Vitamin D has no brain claim in the UK [3].
"Normal" is the key word. These claims mean your brain needs the nutrient to work as usual. They don't promise a sharper mind if you already get enough.
Do brain vitamins work if you're not low?
The trials so far say mostly not. They tested people aged 40 and over with no memory problems, mostly in their 60s and 70s [4].
| Supplement | What trials found | Evidence |
|---|---|---|
| B vitamins | Little or no effect over up to 5 years across 14 studies of 27,882 people, though a 2022 review suggested a slower decline over more than a year [4][8] | Mixed |
| Omega-3 | No benefit on memory and thinking tests in 3 trials of healthy people aged 60 and over [9] | Moderate |
| Vitamin D with calcium | No effect on thinking over up to 10 years in one trial of 4,143 people [4] | Early |
| Multivitamin | Better memory and overall thinking over 2 to 3 years, across 3 studies of 5,203 people aged 60 and over, all within one US trial [10][11] | Moderate |
The Cochrane review behind the B vitamin and vitamin D rows covered 28 studies with more than 83,000 people. Most people in it were in studies not designed to test thinking, and only 10 of the studies ran for more than 5 years on average [4]. The multivitamin trial was funded by the US National Institute on Aging, and the multivitamin maker partly supplied the pills without a role in the analysis [10]. Our Ingredient Atlas lists the studies on each vitamin in people.
So the useful question isn't which pill is best. It's whether you might be low in something.
Does vitamin B12 help memory?
It helps if you're low. Problems with memory, understanding and judgement are among the symptoms of vitamin B12 or folate deficiency anaemia, along with feeling weak or tired [12]. If your levels are fine, trials of B vitamins found little or no effect on memory [4].
Some people are more likely to run low [13].
- people with pernicious anaemia, the most common cause in the UK, which is more common in women around 60
- people on a vegan diet without B12 supplements or fortified foods
- people taking some medicines, including metformin and proton pump inhibitors
If that sounds like you, see a GP. Deficiency can often be diagnosed from your symptoms and a blood test, and some problems can become permanent if it isn't treated [12]. There's one more reason to check first. Folic acid above 1 mg a day can hide the signs of a B12 shortfall [1].
What about iron, iodine and omega-3?
Iron. Iron deficiency anaemia can cause tiredness, lack of energy and headaches [14]. Heavy periods are a very common cause, and the GP will usually check with a blood test [14]. Women aged 19 to 49 need 14.8 mg of iron a day and men 8.7 mg [5].
Iodine. Iodine helps make thyroid hormones. Adults need 140 micrograms a day, mostly from milk, dairy, eggs and fish, so a strict vegan diet may fall short without fortified foods [2].
Omega-3. DHA contributes to normal brain function, based on 250 mg a day [3]. The NHS advises at least 2 portions of fish a week, including 1 of oily fish [7].
Who might need a vitamin supplement?
Start with what applies to you. Here are the NHS steps worth knowing.
- Everyone, autumn and winter. Consider 10 micrograms of vitamin D a day in autumn and winter, when sunlight is too weak [15].
- Vegan diets. Use fortified foods or supplements for vitamin B12, iodine, vitamin D, selenium and calcium [16].
- Trying for a baby. Take 400 micrograms of folic acid a day until 12 weeks of pregnancy [1].
- Tired all the time, or memory changes? See a GP for a blood test before buying supplements [12][14].
- Everyone else. The NHS says a varied, balanced diet should give you the B vitamins you need [1].
Find your line on that list and act on it this week. Leave the rest.
Can vitamins help focus and brain fog?
Only if a shortfall is part of the cause. Our brain fog guide works through the common causes, from sleep to low iron or B12. For supplements ranked by goal, including focus and memory, see our guide to the best nootropics in the UK.
Where Nooroots fits
Nooroots Triple Magnesium is a food supplement with magnesium glycinate, citrate and malate, in three capsules a day. Magnesium contributes to normal psychological function and to normal functioning of the nervous system [3].
Frequently asked questions
What is the best vitamin for the brain?
No single vitamin is best. Vitamin B12, folate, B6, iodine, iron and zinc all have UK claims for normal brain or psychological function, and the one that matters most is the one you're short of [3].
Does vitamin B12 help memory?
Only if you're low. B12 deficiency can cause memory problems, but trials found little or no benefit from B vitamins in people who already get enough [4][12].
What vitamin deficiency causes memory problems?
Low vitamin B12 or folate can cause them. The NHS lists problems with memory, understanding and judgement among the symptoms, and a GP can check with a blood test [12].
Do multivitamins help memory?
Possibly a little in older adults. Three studies within one large US trial, with 5,203 people aged 60 and over, found better thinking and memory scores with a daily multivitamin, which other trials still need to repeat [11].
Is omega-3 good for your brain?
DHA, an omega-3 in oily fish, contributes to normal brain function at 250 mg a day. Trials of omega-3 capsules in healthy older people found no benefit on memory tests [3][9].
Can vitamins improve focus?
Not if your levels are already fine. Iron, iodine and zinc contribute to normal cognitive function, which matters when you're short [3].
Read more about the common causes of a foggy head in our brain fog guide.
References
Every source here is listed so you can read it yourself. This guide is for general information and doesn't replace advice from your GP. We check it again at least every six months.
- NHS. Vitamins and minerals: B vitamins and folic acid. Page last reviewed 3 August 2020. Accessed 1 November 2026. nhs.uk/conditions/vitamins-and-minerals/vitamin-b
- NHS. Vitamins and minerals: iodine. Page last reviewed 3 August 2020. Accessed 1 November 2026. nhs.uk/conditions/vitamins-and-minerals/iodine
- Department of Health and Social Care. Great Britain nutrition and health claims (NHC) register, spreadsheet of 19 May 2026. Accessed 1 November 2026. gov.uk/government/publications/great-britain-nutrition-and-health-claims-nhc-register
- Rutjes AW, Denton DA, Di Nisio M, Chong LY, Abraham RP, Al-Assaf AS et al. (2018). Vitamin and mineral supplementation for maintaining cognitive function in cognitively healthy people in mid and late life. Cochrane Database of Systematic Reviews 12(12): CD011906. PMID 30556597
- NHS. Vitamins and minerals: iron. Page last reviewed 3 August 2020. Accessed 1 November 2026. nhs.uk/conditions/vitamins-and-minerals/iron
- NHS. Vitamins and minerals: others (magnesium and zinc sections). Page last reviewed 3 August 2020. Accessed 1 November 2026. nhs.uk/conditions/vitamins-and-minerals/others
- NHS. Fish and shellfish nutrition. Page last reviewed 26 June 2026. Accessed 1 November 2026. nhs.uk/live-well/eat-well/food-types/fish-and-shellfish-nutrition
- Wang Z, Zhu W, Xing Y, Jia J, Tang Y (2022). B vitamins and prevention of cognitive decline and incident dementia: a systematic review and meta-analysis. Nutrition Reviews 80(4): 931-949. PMID 34432056
- Sydenham E, Dangour AD, Lim WS (2012). Omega 3 fatty acid for the prevention of cognitive decline and dementia. Cochrane Database of Systematic Reviews 6: CD005379. PMID 22696350
- Baker LD, Manson JE, Rapp SR, Sesso HD, Gaussoin SA, Shumaker SA et al. (2023). Effects of cocoa extract and a multivitamin on cognitive function: A randomized clinical trial. Alzheimer's & Dementia 19(4): 1308-1319. PMID 36102337
- Vyas CM, Manson JE, Sesso HD, Cook NR, Rist PM, Weinberg A et al. (2024). Effect of multivitamin-mineral supplementation versus placebo on cognitive function: results from the clinic subcohort of the COcoa Supplement and Multivitamin Outcomes Study (COSMOS) randomized clinical trial and meta-analysis of 3 cognitive studies within COSMOS. The American Journal of Clinical Nutrition 119(3): 692-701. PMID 38244989
- NHS. Vitamin B12 or folate deficiency anaemia: symptoms. Page last reviewed 20 February 2023. Accessed 1 November 2026. nhs.uk/conditions/vitamin-b12-or-folate-deficiency-anaemia/symptoms
- NHS. Vitamin B12 or folate deficiency anaemia: causes. Page last reviewed 20 February 2023. Accessed 1 November 2026. nhs.uk/conditions/vitamin-b12-or-folate-deficiency-anaemia/causes
- NHS. Iron deficiency anaemia. Page last reviewed 26 January 2024. Accessed 1 November 2026. nhs.uk/conditions/iron-deficiency-anaemia
- NHS. Vitamins and minerals: vitamin D. Page last reviewed 3 August 2020. Accessed 1 November 2026. nhs.uk/conditions/vitamins-and-minerals/vitamin-d
- NHS. The vegan diet. Page last reviewed 5 June 2026. Accessed 1 November 2026. nhs.uk/live-well/eat-well/how-to-eat-a-balanced-diet/the-vegan-diet
