Vitamin D: The Sunshine Vitamin

Although Vitamin D is commonly called a vitamin, it is not actually an essential dietary vitamin in the strict sense, as it can be synthesized in adequate amounts by all mammals from sunlight. Of course, that in itself sets up a bit of a conundrum, as we are told to avoid the sun’s harmful rays as they can cause skin cancer!

Vitamin D is a group of fat-soluble secosteroids. In humans, vitamin D is unique because it can be ingested as cholecalciferol (vitamin D₃) or ergocalciferol (vitamin D₂) and because the body can also synthesize it (from cholesterol) when sun exposure is adequate (hence its nickname, the “sunshine vitamin”). The skin can in fact manufacture Vitamin D with as little as only 20 minutes sun exposure over a small portion of your body.

Vitamin D deficiency can manifest itself in many different ways including chronic pain, weak bones, frequent infections, depression, etc., but the same will not be true for everyone who is deficient. Vitamin D appears to play a role in many health conditions including the following:

Bone health
Vitamin D deficiency causes osteomalacia (called rickets when it occurs in children). One of the most important roles of vitamin D is to maintain skeletal calcium balance by promoting calcium absorption in the intestines, promoting bone resorption by increasing osteoclast number, maintaining calcium and phosphate levels for bone formation, and allowing proper functioning of parathyroid hormone to maintain serum calcium levels.

Some studies have shown that supplementation with vitamin D and calcium may improve bone mineral density slightly, as well as decreasing the risk of fractures in certain groups of people. However, there does need to be sufficient calcium in order for Vitamin D to be effective for bone health.

Atheroscclerosis
While there are no studies linking sunlight and atherosclerosis, people who live in low altitudes have a higher death rate from coronary heart disease. There is less sunlight in lower altitudes. The thinking is that the connection of less sunlight producing less Vitamin D, could be one component that could easily be remedied by taking a Vitamin  D supplement.
Congestive Heart Faliure
According to Howard J. Eisen MD, chief of cardiology division at Drexel University College of Medicine, Philadelphia,

“Adults with decreased serum 25(OH)D [vitamin D] levels have significantly higher risk of death from [heart failure] and premature death, and this may beget additional justification for the study of vitamin D supplementation…”

Heart failure is also called congestive heart failure (CHF). CHF occurs when the heart can no longer pump enough blood to the rest of the body.?? Nearly 5 million Americans currently suffer from heart failure. Annually, about 550,000 new cases of CHF are now diagnosed and 300,000 die from the condition.
Multiple sclerosis
Low levels of vitamin D are associated with

multiple sclerosis. Supplementation with vitamin D may have a protective effect. A clinical trial sponsored by Charite University in Berlin, Germany was begun in 2011, with the goal of examining the efficacy, safety and tolerability of vitamin D3 in the treatment of Multiple Sclerosis.

Immune Function
Vitamin D appears to have effects on immune function, it has been thought to play a role in influenza, with lack of vitamin D synthesis during the winter as one explanation for high rates of influenza infection during the winter months

In a clinical trial led by Mitsuyoshi Urashima and conducted by the Division of Molecular Epidemiology in the the Department of Pediatrics at the Jikei University School of Medicine Minato-ku in Tokyo found that vitamin D was extremely effective at halting influenza infections in children. The trial appeared in the March, 2010 issue of the American Journal of Clinical Nutrition (Am J Clin Nutr (March 10, 2010).

In this double-blind, placebo-controlled study of 334 children, half of which were given 1200 IUs per day of vitamin D3. While 31 of 167 children in the placebo group contracted influenza over the four-month duration of the study, only 18 of 168 children in the vitamin D group did. This means vitamin D was responsible for an absolute reduction of nearly 8%, which compares very favorably to current flu vaccines that according to the latest scientific evidence, achieve a 1% reduction in influenza symptoms.

For viral infections, other implicated factors include low relative humidities produced by indoor heating and cold temperatures that favor virus spread. Low levels of vitamin D appear to be a risk factor for tuberculosis, and historically it was used as a treatment.  Vitamin D may also play a role in HIV.

Weight Management
A study published online recently in the Journal of Women’s Health found that women with low vitamin D status may be prone to weight gain. The results promoted the authors to call for more research on the topic before there can be a supplement recommendation made for weight loss purposes.

The study by Erin LeBlanc, MD, an endocrinologist and researcher at the Kaiser Permanente Center for Health Research in Portland, Oregon examined vitamin D status and weight for 4,659 women over the age of 65. When looking at vitamin D levels of women who lost or maintained weight, the researchers found no association with vitamin D status.

Among the 571 women who gained weight during the five year study, those with insufficient vitamin D levels (<30ng/mL) gained an average of 18.6 lbs., while women with sufficient levels gained an average of 16.4 lbs.

The researchers also found that women with insufficient levels when the study began weighed more than the women with vitamin D levels of 30 ng/mlL or above.

Vitamin D deficiency
As humans, we are designed to fulfill vitamin D needs by producing it in response to exposure to ultraviolet-B (UVB) light from the Sun. Vitamin D deficiency occurs as a result of a lack of consistent exposure of bare skin to the Sun’s UVB light. The sun avoidance of the modern lifestyle, is the predominant factor influencing the rise we see in vitamin D deficiency today. In addition, due to the physiology of vitamin D, certain members of the population are at even greater risk.
Vitamin D deficiency risk factors:
• African Americans are at greatest risk of vitamin D deficiency, due to higher skin melanin content.

• Insufficient UVB exposure – working and playing indoors, covering up with clothes or sunscreen when outside.

• Aging – seniors are at greater risk due to lack of mobility and skin that is less responsive to UVB

• Breastfeeding – breastfeeding will result in vitamin D deficiency in the baby if the mother fails to ensure her own levels are high    enough to provide for her baby’s needs. When the mother is deficient, the breast-fed child will be deficient due to the low vitamin D content of the mother’s breast milk.

• Obesity – fat-soluble vitamin D gets trapped in adipose tissue, preventing its metabolization and utilization by the body.

Nowadays, Vitamin D deficiency is very common and very simple to correct by taking a Vitamin D3 supplement. Most physicians recommend taking 1000 IU’s daily.