How Sunlight Can Influence Your Mood
by Dr. Mercola

According to a paper published in the journal Dermato Endocrinology,6 a large number of molecules (chromophores) found in the different layers of your skin absorb and interact with ultraviolet rays, producing a number of complex and synergistic effects.

There are additional chromophores in your mitochondria electron transport chain that respond to near infrared. This complex stimulus of sunlight affects not only your physical health by preventing diseases, it also impacts your mood and mental health. For example:

• Your body uses the near-infrared light spectrum to produce mitochondrial energy and maintain systemic equilibrium.

Near-infrared also primes the cells in your retina for repair and regeneration, which explains why light-emitting diode (LED) lighting — which is devoid of infrared — is so harmful for your eyes. To learn more about this, please see my interview with Wunsch, "How LED Lighting May Compromise Your Health."

Now, if near-infrared plays such an important role in your body's energy production, it seems reasonable to conclude that if you're running low on adenosine triphosphate (ATP) — cellular energy — due to insufficient amounts of sunlight exposure, you'd start feeling sluggish and tired, and possibly depressed.

• Sunlight also regulates your circadian rhythm, and light therapy has been shown to be effective against depression, both SAD and non-seasonal major depression.

When it's dark, your melatonin levels increase, which is why you may feel tired when the sun starts to set. In the heart of winter, this may be at as early as 4:00 p.m.

• Ultraviolet (UV) light also stimulates epidermal cells known as keratinocytes to make beta-endorphins, which have a mood-boosting effect.

• Serotonin is also released in response to sunlight, which helps elevate your mood and energy.

• UVA generates nitric oxide (NO) in your skin, which influences your body in a number of beneficial ways. It stimulates up to 60 percent of your blood to flow to your skin capillaries where they absorb this energy and infrared radiation.

The UVA actually helps kill any infections in your blood while the infrared recharges your cellular battery.

NO also protects your heart by relaxing your blood vessels and lowering your blood pressure, stimulates your brain, and acts as a natural antioxidant. By lowering inflammation, it could have a beneficial impact on your mental health, as depression is strongly linked to chronic, low-grade inflammation.

Part of why vitamin D appears to improve depression relates to the fact that it's a potent anti-inflammatory.

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.