Although further research on the relationship between vitamin D and depression and other mental health disorders is required, there are now a number of studies showing that vitamin D is important for both the prevention and treatment of mental illnesses such as depression, seasonal affective disorder (SAD), anxiety disorders and schizophrenia. A selection of studies is outlined below:
- Vitamin D and depressive symptoms were assessed in 441 overweight and obese people1. In a randomised, placebo controlled fashion, subjects were then given either 20,000IU or 40,000 IU of vitamin D or a placebo for one year. Depressive symptoms were then reassessed over the course of a year. Prior to treatment, those subjects with vitamin D levels less than 40nmol/L reported greater depressive symptoms. Among the two groups given vitamin D there was a significant improvement in depression scores measured one year later. No such changes were reported among those receiving a placebo. The researchers concluded that there appeared a relationship between serum levels of vitamins (D) and symptoms of depression with those subjects supplemented with high doses of vitamin D experiencing improvements in depressive symptomatology.
- A study of six women with serum vitamin D levels less than 40 ng/ml were assessed for depressive symptoms both before and after they were given vitamin D supplements. Significant improvements in mood were reported after supplementation2.
- A review article by Murphy and Wagner (2008)3 concluded that four of six reviewed studies on vitamin D levels and mood disorders in women showed an association between low vitamin D levels and mood disorders (premenstrual syndrome, seasonal affective disorder, non-specified mood disorder and major depressive disorder). The authors concluded that there is a possible biochemical mechanism between vitamin D and mood disorders affecting women, and rigorous studies were warranted.
- Vitamin D, calcium phosphate and parathyeoidal hormonal levels were assessed in 34 patients with schizophrenia, 30 patients with alcohol addiction, 25 patients with major depression and 31 healthy controls4. The researchers found that only vitamin D levels were significantly lower in all groups of psychiatric patients compared to the normal controls. There were no differences in vitamin D levels across the 3 psychiatric groups.
- In a randomised double-blind study5, 44 health subjects were given 400 IU, 800 IU or no vitamin D3 for 5 days during late winter. Results on a self-report measure showed that vitamin D3 supplementation significantly enhanced positive affective and there was some evidence of a reduction in negative affect.
As is demonstrated by these studies there is definitely a relationship between vitamin D and depression and other mental health problems. There have also been positive findings showing that vitamin D supplementation can lead to improved mood. Although the exact mechanism/s for vitamin D’s effect on mental health is still unknown it is hypothesised that it could be due to vitamin D’s impact in the following areas:
- Regulates glucocorticoid (stress hormone) output. Problems with stress hormone production (either too high or too low production) is associated with poorer mental health and it has been found that vitamin D can regulate stress hormone production6.
- Regulates the immune response. It is now confirmed in numerous studies that vitamin D has significant immune-enhancing benefits. In relation to mental health, studies have consistently found dysfunctional inflammatory process in depression and mental illness. Vitamin D may therefore play a role in improving mental health though its anti-inflammatory effects.
- Increases catecholamine production. Tyrosine hydroxylase is an enzyme required for the production of the catecholamines, dopamine, adrenaline and noradrenaline. These neurotransmitters are implicated in a range of mental health problems, including depression, bipolar disorders and schizophrenia. Animal studies indicate that tyrosine hydroxylase is increased by vitamin D7.
- Increases serotonin production. The role of serotonin in mental health is now well established. One study found that summer sunlight increased brain serotonin levels twice as much as winter sunlight8.
While many people continue to question the notion that vitamin D deficiency can cause mental health problems the studies summarised above certainly show that there is a strong relationship. I acknowledge that further research on vitamin D and depression and other mental health disorders is required, however, it certainly would be advisable to optimise vitamin D levels. Not only could it improve mental health but it will also lead to a large range of other health benefits.
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Testing of vitamin D and vitamin D deficiency treatment
- Jorde R, Sneve M, Figenschau Y, Svartberg J, Waterloo K. (2008) Effects of vitamin D supplementation on symptoms of depression in overweight and obese subjects: randomized double blind trial. Journal of Internal Medicine. 264(6):599-609.
- Shipowick CD, Moore CB, Corbett C, Bindler R. (2009) Vitamin D and depressive symptoms in women during the winter: a pilot study. Appl Nurs Res. 22(3):221-5.
- Murphy PK, Wagner CL. (2008) Vitamin D and mood disorders among women: an integrative review. J Midwifery Womens Health. 53(5):440-6.
- Schneider B, Weber B, Frensch A, Stein J, Fritz J. (2000) Vitamin D in schizophrenia, major depression and alcoholism. J Neural Transm. 107(7):839-42.
- Lansdowne AT, Provost SC. (1998) Vitamin D3 enhances mood in healthy subjects during winter. Psychopharmacology (Berl). 135(4):319-23.
- Obradovic D, Gronemeyer H, Lutz B, Rein T. (2006) J Neurochem. Cross-talk of vitamin D and glucocorticoids in hippocampal cells. 96(2):500-9.
- Puchacz E, Stumpf WE, Stachowiak EK, Stachowiak MK. (1996) Vitamin D increases expression of the tyrosine hydroxylase gene in adrenal medullary cells. Brain Res Mol Brain Res. 1996 Feb;36(1):193-6.
- Lambert GW, Reid C, Kaye DM, Jennings GL, Esler MD. Effect of sunlight and season on serotonin turnover in the brain. Lancet. 2002 Dec 7;360(9348):1840-2.