Why Your Brain Needs Vitamin D

Winter is coming, so now is the time to ensure you are optimising your vitamin D level. Why?

Apart from being an essential for your bones, heart and immunity, vitamin D is a brain essential. You want vitamin D running around your brain.

Vitamin D is an allrounder as far as your brain and mental health is concerned. It helps neurotransmission and exerts anti-inflammatory and neuroprotective activities within the brain by reducing both inflammation and oxidative stress.[i]

Mood Boost with Vitamin D

Generally speaking, the lower your vitamin D, the worse your mood which makes vitamin D especially important to supplement from October to March if you live in the UK or similar latitude, when the angle of the sun is too low and you’re also less likely to get outdoors exposing your skin to sunlight. It’s best to assume that we are all deficient in winter, unless you travel to the sun, and need to supplement around 3,000iu a day.

Vitmin D encourages the conversion of tryptophan into serotonin in the brain, where you want it, and suppresses it in the gut.[ii] This may be partly why the lower your vitamin D level, the more depressed you are likely to feel. If your mood takes a dip in winter months this is a key sign that you might need more. That’s what researchers at the University of Tromso in Norway found on testing 441 volunteers who were given a test for depression and also a test for blood levels of vitamin D. The volunteers were then given Vitamin D supplements or placebo. Tested one year on, those given vitamin D, but not those given the placebos, had substantially lower depression ratings.[iii]

However, you don’t have to wait for a year to get a lift in mood. An eight-week study in Australia found that some of those given vitamin D supplements had an improvement in mood in only five days.[iv] Another study, in Iran, gave a single vitamin D injection and reported benefit in depression when measured 3 months on.[v]

It’s also very important for children and teenagers. A study of 89 children and adolescents with depression compared to ‘control’ patients of the same age. The depressed patients had much higher homocysteine, indicating worse methylation, and clearly lower B12 and vitamin D levels with the levels predicting the severity of their symptoms.[vi]

Since vitamin D stores, there is no need to supplement daily. You can take a weekly dose. In the Norwegian study above they gave 20,000iu or 40,000iu weekly. Both worked and there wasn’t a big difference in the effects on mood. So, you can assume that 20,000iu weekly, or 3,000iu daily would likely be sufficient. Vitamin D3 , which is what is made in the skin and present in seafood and eggs,is better than vitamin D2, the plant form. Lichen also provide a vegan source of vitamin D3.

Vitamin D3 is hydroxylated in the liver to form 25(OH)D3 the major circulating form of vitamin D in the blood and the commonly accepted measure of vitamin D status which is what this test measures. Circulating 25(OH)D3 levels reflect endogenous production as well as vitamin supplementation. Vitamin D deficiency is linked with many chronic diseases, including autoimmune diseases, diabetes, cardiovascular disease, cancer as well as cognitive decline. Optimal levels of 25(OH)D3 are certainly above 32ng/mL (80 nmol/l) and ideally over 40ng/ml (100nmol/l).

The yardstick for what you need is really whatever gets your blood level into the optimal range. In the Norwegian study above, those given 20,000iu a week averaged a blood level of 88 nmol/l, while those given 40,000iu averaged 111nmol/l. It is now well recognised that levels above 75nmol/l correlate with good health for many health measures, while levels above 100nmol/l might be even better is some respects. My recommendation is to test yourself and consider anything below 50 to be deficient, and above 75 to be sufficient with an optimal level being closer to 100nmol/l. If you then supplement 3,000iu daily, like in my High Strength Vitamin D, or seven times this weekly, especially from October to March, retest yourself against these yardsticks.

Foodforthebrain.org offer a simple and reliable home test for vitamin D.

Daryl, a patient at the Brain Bio Centre, is a case in point. He found that, particularly during the winter, he felt very low, irritable and angry, and was suffering from what he described as ‘brain fog’. His blood tests showed very low levels of both vitamin D and essential fats. We gave him supplements of both vitamin D and omega-3, and recommended eating more oily fish. He quickly noticed what he described as a massive improvement’ in his symptoms. He was no longer waking with headaches for the first time in six years, instead feeling thoroughly refreshed.

Vitamin D Prevents Dementia

Vitamin D protectsyour brain from dementia. Vitamin D deficiency increases risk of Alzheimer’s.[vii] In a study in France involving 912 elderly patients followed for twelve years, a total of 177 dementia cases occurred. Those with low vitamin D levels had nearly three-fold increased risk of Alzheimer’s.[viii] Supplementing 800iu (20mcg) a day for 12 months has also been shown to improve cognitive function.[ix]

Supplements also help ward off dementia, according to a recent, large-scale study involving over twelve thousand dementia-free 70+ year olds in the US.[x] More than a third (37%) took supplements of vitamin D. Those who did had a 40% lower incidence of dementia. Professor Zahinoor Ismail, of the University of Calgary and University of Exeter, who led the research, said: “We know that vitamin D has some effects in the brain that could have implications for reducing dementia, however so far, research has yielded conflicting results. Overall, we found evidence to suggest that earlier supplementation might be particularly beneficial, before the onset of cognitive decline.”

You want to get your blood level above 75nmol/l (30 ng/ml) which usually means supplementing 3,000iu from October to March for those in the Northern (or Southern) hemisphere.

Full Spectrum Lights and Sun beds

The other way to boost your light exposure is with light therapy. Canadian researchers compared the effects of an anti-depressant (fluoxetine), placebo or 30 minutes daily of light therapy as soon as possible on waking for people with major depression. Light therapy was both superior to placebo and anti-depressants, which were also no better than placebo.[xi] I have a full spectrum light in my study, which I put on in the winter, when I’m writing in the early morning, before the sun comes up.

Sun beds also promote vitamin D and make you feel good. In fact, people can become addicted to sun beds. Interestingly, vitamin D deficiency is also associated with greater opioid addiction[xii] suggesting the need to up vitamin D intake to reduce cravings. Sun exposure, which promotes higher vitamin D levels, reduces opioid addiction.

Best Foods for Vitamin D

The best food sources of vitamin D are oily fish and eggs. A serving of salmon or mackerel is likely to give you 400iu of vitamin D. Two eggs will provide about 130iu. In some countries, not the UK, milk is fortified with vitamin D but, otherwise, it is not a great source. Some mushrooms are purposely fortified with vitamin D by exposing them to UV light.

In summary, vitamin D is an allrounder as far as your brain and mental health is concerned and it’s worth ensuring your level is optimal, both for brain and body, throughout winter by supplementing 3.000iu or whatever you need to keep your blood level above 75nmol/l.

Further Information

See HOLFORDirect for a high strength Vitamin D3 3000iu.


[i] Jayedi A, Rashidy-Pour A, Shab-Bidar S. Vitamin D status and risk of dementia and Alzheimer’s disease: A meta-analysis of dose-response †. Nutr Neurosci. 2019 Nov;22(11):750-759. doi: 10.1080/1028415X.2018.1436639. Epub 2018 Feb 15. PMID: 29447107

[ii] Patrick RP, Ames BN. Vitamin D hormone regulates serotonin synthesis. Part 1: relevance for autism. FASEB J. 2014 Jun;28(6):2398-413. doi: 10.1096/fj.13-246546. Epub 2014 Feb 20. PMID: 24558199.

[iii] Jorde R, Sneve M, Figenschau Y, Svartberg J, Waterloo K. Effects of vitamin D supplementation on symptoms of depression in overweight and obese subjects: randomized double blind trial. J Intern Med. 2008 Dec;264(6):599-609. doi: 10.1111/j.1365-2796.2008.02008.x. Epub 2008 Sep 10. PMID: 18793245.

[iv] Khoraminya N, Tehrani-Doost M, Jazayeri S, Hosseini A, Djazayery A. Therapeutic effects of vitamin D as adjunctive therapy to fluoxetine in patients with major depressive disorder. Aust N Z J Psychiatry. 2013 Mar;47(3):271-5. doi: 10.1177/0004867412465022. Epub 2012 Oct 23. PMID: 23093054. Xxxx check the some in 5 days

[v] Mozaffari-Khosravi H, Nabizade L, Yassini-Ardakani SM, Hadinedoushan H, Barzegar K. The effect of 2 different single injections of high dose of vitamin D on improving the depression in depressed patients with vitamin D deficiency: a randomized clinical trial. J Clin Psychopharmacol. 2013 Jun;33(3):378-85. doi: 10.1097/JCP.0b013e31828f619a. PMID: 23609390.

[vi] Esnafoglu E, Ozturan DD. The relationship of severity of depression with homocysteine, folate, vitamin B12, and vitamin D levels in children and adolescents. Child Adolesc Ment Health. 2020 Nov;25(4):249-255. doi: 10.1111/camh.12387. Epub 2020 Apr 18. PMID: 32304285.

[vii] Chai B, Gao F, Wu R, Dong T, Gu C, Lin Q, Zhang Y. Vitamin D deficiency as a risk factor for dementia and Alzheimer’s disease: an updated meta-analysis. BMC Neurol. 2019 Nov 13;19(1):284. doi: 10.1186/s12883-019-1500-6. PMID: 31722673; PMCID: PMC6854782.

[viii] Jia J, Hu J, Huo X, Miao R, Zhang Y, Ma F. Effects of vitamin D supplementation on cognitive function and blood Aβ-related biomarkers in older adults with Alzheimer’s disease: a randomised, double-blind, placebo-controlled trial. J Neurol Neurosurg Psychiatry. 2019 Dec;90(12):1347-1352. doi: 10.1136/jnnp-2018-320199. Epub 2019 Jul 11. PMID: 31296588.

[ix] Feart C, Helmer C, Merle B, Herrmann FR, Annweiler C, Dartigues JF, Delcourt C, Samieri C. Associations of lower vitamin D concentrations with cognitive decline and long-term risk of dementia and Alzheimer’s disease in older adults. Alzheimers Dement. 2017 Nov;13(11):1207-1216. doi: 10.1016/j.jalz.2017.03.003. Epub 2017 May 16. PMID: 28522216.

[x] Ghahremani M, Smith EE, Chen HY, Creese B, Goodarzi Z, Ismail Z. Vitamin D supplementation and incident dementia: Effects of sex, APOE, and baseline cognitive status. Alzheimers Dement (Amst). 2023 Mar 1;15(1):e12404. doi: 10.1002/dad2.12404. PMID: 36874594; PMCID: PMC9976297.

[xi] Lam RW, Levitt AJ, Levitan RD, Enns MW, Morehouse R, Michalak EE, Tam EM. The Can-SAD study: a randomized controlled trial of the effectiveness of light therapy and fluoxetine in patients with winter seasonal affective disorder. Am J Psychiatry. 2006 May;163(5):805-12. doi: 10.1176/ajp.2006.163.5.805. PMID: 16648320.o015

[xii] Kemény LV, Robinson KC, Hermann AL, Walker DM, Regan S, Yew YW, Lai YC, Theodosakis N, Rivera PD, Ding W, Yang L, Beyer T, Loh YE, Lo JA, van der Sande AAJ, Sarnie W, Kotler D, Hsiao JJ, Su MY, Kato S, Kotler J, Bilbo SD, Chopra V, Salomon MP, Shen S, Hoon DSB, Asgari MM, Wakeman SE, Nestler EJ, Fisher DE. Vitamin D deficiency exacerbates UV/endorphin and opioid addiction. Sci Adv. 2021 Jun 11;7(24):eabe4577. doi: 10.1126/sciadv.abe4577. PMID: 34117054; PMCID: PMC8195487.