How Sunlight Affects Your Mental Health
By Dr. Mercola
Sunlight has a profound impact on your mental health — more so than any other weather phenomenon. That's the conclusion of a recent study looking at links between weather and depression.1
Mental health data from more than 16,000 Brigham Young University students was used. Assessments had been filled out several times by each person over the course of six years. Each assessment was then matched to local weather data.
Nineteen different environmental factors, including solar irradiance (the amount of sunlight reaching the Earth), cloud cover, rain, wind chill, barometric pressure and smog levels were accounted for.
In the end, the only factor that really mattered was the amount of time between sunrise and sunset. None of the other factors had any significant association with emotional distress — provided there was enough sunlight.
This doesn't surprise me. It's been estimated2 that as many as 20 percent of Americans are affected by Seasonal Affective Disorder (SAD) each winter, suffering from the blues, fatigue and in some cases, more serious depression, as sunlight grows scarce.
What differentiates SAD from regular depression is that a full remission occurs in the spring and summer months.
Depression Rates Rise During Fall and Winter
Indeed, as the days got shorter through fall and winter, self-reports of depression rose, whether the student had been diagnosed with SAD or not. According to the authors:
"These findings suggest the need for institutions and public health entities to plan for intervention and prevention resources and strategies during periods of reduced sun time."
The researchers note that more research is needed to evaluate related factors such as Vitamin D intake, amount of time actually spent outdoors and sunbed use. Indeed, a deficiency of the vital nutrient of Vitamin D, which can be counteracted with Vitamin D3 supplements, is strongly associated with a higher risk of depression.
For example, research has shown having a Vitamin D level below 20 nanograms per milliliter (ng/mL) can raise your risk for depression by as much as 85 percent, compared to having a Vitamin D level greater than 30 ng/mL.
A number of studies have also confirmed that Vitamin D supplementation can help alleviate symptoms of depression.3
A study published in 2015,4 which looked at healthy women aged 18 to 25 who lived in the Pacific Northwest during the fall, winter and spring, found that Vitamin D insufficiency (30 ng/ml or lower) could predict the emergence of clinically significant depressive symptoms.
The link remained even after controlling for factors such as season, body mass index, race, diet, exercise and time spent outdoors.
By the fourth and final week of the study, 46 percent of the women had insufficient levels of Vitamin D, and during the course of the study up to 42 percent of them showed signs of clinically significant depression, based on the Center for Epidemiologic Studies Depression scale. As reported by HCP Live:5
"'Vitamin D supplements are inexpensive and readily available,' [lead author David] Kerr concluded, adding that the findings are consistent with literature that supports seasonal depressive symptoms."
I am somewhat skeptical of using oral Vitamin D to address this problem. Vitamin D levels in the above study likely correlate well with SAD as they indicate sunlight exposure. When you separate the sunlight from Vitamin D by swallowing it, I suspect you are dramatically reducing the mental benefits.
Vitamin D Deficiency Predisposes You to Depression
Getting back to Vitamin D, there's ample evidence suggesting Vitamin D plays an important role in mental health, so if fall and winter months leave you feeling blue, you'd be wise to get your levels checked. If you're below 40 ng/mL, a Vitamin D supplement would be advisable.
- In one 2006 study, seniors with Vitamin D levels below 20 ng/ml were found to be 1,100 percent more prone to be depressed than those with higher levels7
- A 2007 study suggested that Vitamin D deficiency is responsible for symptoms of depression and anxiety in patients with fibromyalgia8
- Vitamin D deficiency is also a well-recognized cause in SAD9
- A double-blind randomized trial published in 2008 suggested there's a CAUSAL relationship between low Vitamin D levels and depression, noting that high doses of Vitamin D were effective at ameliorating symptoms of depression10
- In a 2011 study, the authors also pointed out that:11"Effective detection and treatment of inadequate Vitamin D levels in persons with depression and other mental disorders may be an easy and cost-effective therapy which could improve patients' long-term health outcomes as well as their quality of life"
Based on the evaluation of healthy populations that get plenty of natural sun exposure, the optimal range for general physical and mental health appears to be somewhere between 40 and 70 ng/ml. So, if you're depressed, get your Vitamin D level checked, and to address any insufficiency or deficiency. The D*Action Project by GrassrootsHealth is one cost effective testing solution.
Just keep in mind that if you opt for a Vitamin D supplement, you also need to take Vitamin K2 and magnesium, as these nutrients work in tandem. Also, since Vitamin D is fat-soluble, taking it some form of healthy fat will help optimize absorption. Vitamin A, zinc and boron are other important cofactors that interact with Vitamin D.
The Role of Vitamin D in Disease Prevention
A growing body of evidence shows that Vitamin D plays a crucial role in disease prevention and maintaining optimal health. There are about 30,000 genes in your body, and Vitamin D affects nearly 3,000 of them, as well as Vitamin D receptors located throughout your body.
How Vitamin D Performance Testing Can Help Optimize Your Health
Is it any wonder then that no matter what disease or condition is investigated, Vitamin D appears to play a crucial role? This is why I am so excited about the D*Action Project by GrassrootsHealth. Dr. Robert Heaney is the research director of GrassrootsHealth and is part of the design of the D*action Project as well as analysis of the research findings.
GrassrootsHealth shows how you can take action today on known science with a consensus of experts without waiting for institutional lethargy. It has shown how by combining the science of measurement (of Vitamin D levels) with the personal choice of taking action and, the value of education about individual measures that one can truly be in charge of their own health.
In order to spread this health movement to more communities, the project needs your involvement. To participate, simply purchase the D*Action Measurement Kit and follow the registration instructions included. (Please note that 100 percent of the proceeds from the kits go to fund the research project. I do not charge a single dime as a distributor of the test kits.)
As a participant, you agree to test your Vitamin D levels twice a year during a five-year study, and share your health status to demonstrate the public health impact of this nutrient. There is a $65 fee every six months for your sponsorship of this research project, which includes a test kit to be used at home, and electronic reports on your ongoing progress. You will get a follow up email every six months reminding you "it's time for your next test and health survey."
- Flexable Health