Why Vitamin D Matters for Mood

Vitamin D is an allrounder as far as your brain and mental health is concerned.

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.

How Vitamin D Works to Improve Mood

Vitamin 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]

How to Take Vitamin D

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).

Optimising Vitamin D

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.

Testing Vitamin D Levels

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.

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 Omega 3 and 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.