Unfortunately, the days of summer are coming to and end. Ever wonder why your mood is so much better in the summer time?   Many of us have significantly less stress because our rigid routines are often more lax over the summertime.   In addition to this decreased stress, the increased length of daylight plays an important role in contributing to our well-being.

When the summer days are long, we are exposed to more UVB light. While an excess of UVB rays can lead to sunburns and may ultimately contribute to certain types of cancers, a small amount of daily sun exposure can improve our health, mood and wellbeing.

This is because when our skin is exposed to UVB rays our skin produces Vitamin D. Vitamin D plays a crucial role in bone metabolism and numerous other bodily functions that will be further described below. Vitamin D can be obtained from foods such as fatty fish, beef liver, egg yolks, and fortified foods such as dairy products, orange juice and cereals. However, it is difficult to consume an adequate amount of Vitamin D just from diet alone.

The Vitamin D that is produced by plants is called Vitamin D2 (ergocalciferol). While the Vitamin D that is produced in human skin and is found in meats and animals sources is called Vitamin D3 (cholecalciferol).   Vitamin D3 is a more suitable source of Vitamin D supplementation because it is easier for the body to convert into the active hormone form than Vitamin D2.   In addition, too much Vitamin D2 intake can be toxic.   It is much more difficult to become toxic from Vitamin D3 because the body has a mechanism to prevent too much Vitamin D3 from being overproduced in the skin.

The active hormone form of Vitamin D, calcitriol, is very important because it controls the calcium and phosphorus metabolism in your body and helps to build strong bones.   Some other important roles of the activated Vitamin D hormone include:

• Modulates the immune system
• Improves muscle function
• Decreases fall risk in the elderly
• Improves cardiovascular function
• Has potential anti-cancer effects
• Improves mood, wards off depression

According to the Mayo Clinic there is strong scientific evident for the use of Vitamin D to treat:

• Osteomalacia (softening of the bones in adults)
• Bone pain
• Psoriasis
• Some parathyroid and thyroid issues (requires physician oversight)

In addition, there is good scientific evidence for use of Vitamin D to treat:

• Dental cavities
• Muscle pain and weakness
• Fall prevention

Currently the scientific evidence is inconclusive for the use of Vitamin D to treat:

• Osteoporosis
• Asthma
• Auto-immune diseases
• Bone Density in children
• Cancer prevention
• Cognition
• Infertility
• Fibromyalgia
• Inflammatory bowel Disease
• Cancer prevention in certain types of cancer

According to the National Institutes of Health, it is important to obtain Vitamin D either from the sun or from supplementation, as it appears that we are unable to take in an adequate amount from diet alone. The amount of Vitamin D produced in our bodies is dependent on several factors. The length of time in the sun, the angle of the suns rays, the amount of your body directly exposed to the sun, your proximity to the equator, and the amount of melanin in your skin.

When the sun is directly overhead (you will have a very small shadow) you are absorbing the highest amount of UVB rays. These rays are needed to produce Vitamin D3 in the skin.   Those individuals with darker skin tone, actually produce less Vitamin D3 because the melanin in your skin blocks production, as does the application of sunscreen. At this time, the recommendation is for about 10-15 minutes of direct sun, with a large amount of skin exposure (i.e. chest or back) for optimal Vitamin D production. This should be about ½ the time it takes for your skin to turn pink in the sun. It should not be enough time for you to sustain a sunburn.

At this time, guidelines for vitamin D3 intake differ.   The best way to determine your nutritional needs is to have your 25-hydroxy Vitamin D level checked by your health care provider. In general levels between 30-100 nmol/L are considered normal. However, levels >60 nmol/L appear to be more optimal for promoting health and wellness.   Depending on your level you can determine your need for supplementation or increased sun exposure. If you notice that you are a person who is cheerful during the bright summer days and more depressed during the darker winter days, this might be one indication that vitamin D supplementation may help!!!