Here’s a list of studies about vitamin D, bright light, and depression:

A Randomized Controlled Trial of Vitamin D Supplementation on Perinatal Depression: In Iranian Pregnant Mothers (2016)

Conclusion: This randomized control trial study split 169 pregnant Iranian women in their third trimester into two groups. One group received a placebo, the other received 2,000 IU of vitamin D3 daily for the duration of their pregnancy. Compared to the placebo group, the mothers receiving vitamin D had higher vitamin D levels and lower depression scores during the last month of pregnancy and the two months after childbirth. “The present trial showed that consuming 2000 IU vitamin D3 daily during late pregnancy was effective in decreasing perinatal depression levels.” Alarmingly, this study also found that 72% of the mothers were suffering from vitamin D-deficiency at baseline.

Note: much research has shown that 2,000 IU of vitamin D3 is inadequate for adults who don’t get much unprotected sun exposure. One wonders how much better the depression scores would have been with 5,000 IU of vitamin D daily.


Serum 25-Hydroxyvitamin D Concentrations and Depressive Symptoms Among Young Adult Men and Women (2014)

Conclusion: A study of 615 young adults found that those with lower vitamin D levels had worse depression scores.


Suicidal Patients are Deficient in Vitamin D, Associated with a Pro-Inflammatory Status in the Blood (2014)

Conclusion: 59 suicide attempters were enrolled in a study and tested for their vitamin D status along with non-suicidal depressed people and non-depressed healthy control subjects. 58% of the suicide attempters were clinically deficient in vitamin D and had lower levels than than the non-suicidal depressed subjects and non-depressed, healthy control subjects.


Depression is Associated with Decreased 25-Hydroxyvitamin D and Increased Parathyroid Hormone Levels in Older Adults (2008)

Conclusion: A study of 1,282 Dutch elderly people found that those who reported having minor and major depression had lower vitamin D levels compared to the rest of the participants.


Vitamin D Deficiency is Associated with Low Mood and Worse Cognitive Performance in Older Adults (2006)

Conclusion: A study of 80 older adults found that 58% had inadequate vitamin D levels and those with lower levels had worse scores on depression and cognitive function tests.


Neuropsychological Function in Relation to Serum Parathyroid Hormone and Serum 25-Hydroxyvitamin D Levels. The Tromsø Study. (2006)

Conclusion: This study of 21 patients suffering from secondary hyperparathyroidism found that they had lower vitamin D levels compared to 63 control subjects. Those with lower vitamin D levels also had a higher depression score.


Effect of Sunlight and Season on Serotonin Turnover in the Brain (2002)

Conclusion: A study of 101 healthy men found that their serotonin levels were lowest during winter, when there’s less sunlight, but “rose rapidly” as the amount of bright sunlight increased.


Bright Light Therapy and/or Imipramine for Inpatients with Recurrent Non-Seasonal Depression (2002)

Conclusion: This experiment involving 34 adult in-patients suffering from non-seasonal major depressive order split the patients into three groups to compare the 3-week treatment effectiveness of the following: A) bright light therapy combined with the antidepressant drug imipramine, B) bright light therapy combined with a placebo antidepressant pill, and C) imipramine combined with placebo light therapy. All three groups enjoyed significant improvement, but, AMAZINGLY, just bright light therapy alone (B) was found to be superior to just imipramine (C), as well as the combination of imipramine/bright light (A).


Impact of UVA Exposure on Psychological Parameters and Circulating Serotonin and Melatonin (2002)

Conclusion: This study found that subjects who underwent a UVA irradiation session twice a week for three weeks tested as having higher serotonin levels and lower melatonin levels compared to a control group. The UVA-irradiated group also reported feeling “significantly more balanced, less nervous, more strengthened, and more satisfied with their appearance.” So although you can’t get vitamin D from UVA, this study demonstrates that there are still health benefits of UVA exposure and bright light and that it’s not a bad idea to enjoy a balance of full-spectrum sunlight.


Light Treatment for Nonseasonal Depression: Speed, Efficacy, and Combined Treatment (1998)

Conclusion: Bright light treatment was found to alleviate depression faster than medication. (You know… like SUNLIGHT)


Morning vs Evening Light Treatment of Patients with Winter Depression (1998)

Conclusion: Morning bright light therapy is more effective as an antidepressant compared to evening bright light therapy. (Yep, the sun rises in the morning.)


Bone Mineral Density in Women with Depression (1996)

Conclusion: Compared to normal women, depressed women tend to have lower bone mineral density. Both depression and lower bone mineral density are symptoms of vitamin D deficiency.


Sunny Rooms Expedite Recovery From Severe and Refractory Depressions (1996)

Conclusion: A psychiatric clinic noticed over a period of time that their depressed patients staying in the brighter, sunnier hospital rooms recovered faster than patients staying in dully lit rooms. They looked over their records and realized that the depressed patients in sunny rooms stayed 16.9 days, whereas the depressed patients staying in the dully lit rooms stayed 19.5 days. The patients in the sunny rooms were inadvertently receiving bright light therapy, which has been proven to be an effective treatment for depression.




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