Nature has presented many health benefits to mankind and as a result we depend on it for survival and maintenance of life. Aside from being the major source of light and energy, the sun has a great impact in some physiological processes contributing to well-being and strength.
What is vitamin D?
Vitamins are organic substances required by the body in small quantities for various metabolic processes to go on. Most are not synthesized in the body or are synthesized in small quantities.
Vitamin D is a fat soluble vitamin and it’s needed for calcium homeostasis and other benefits.
Vitamin D is a term used for a range of closely related sterol compounds including; cholecalciferol, calcitriol, alfacalcidol, doxercalciferol, and ergocalciferol.
What are the roles of vitamin D in the body?
Vitamin D is a sterol, sometimes considered to be a hormone or hormone precursor.
Vitamin D is required for proper regulation of calcium and phosphate homeostasis and bone mineralization.
This function results in strong bones and prevents bone loss and other complications.
What are the types of vitamin D?
Different forms of vitamin D are available and are required for specific purposes or indications due to differences in their properties.
Types of vitamin Ds are; cholecalciferol (D3), ergocalciferol (D2), calcitriol, doxercalciferol, maxacalcitol, paricalcitol, calcifediol, and dihydrotachysterol.
How do humans get vitamin D?
Humans get vitamin D from at least 2 major sources.
- Exposure to sunlight
- Dietary sources
Is it only the morning sunshine or any other?
The World Health Organization’s International Agency for Research on Cancer recommends avoiding outdoor activities at midday, wearing clothing to cover the whole body, and daily use of sunscreen on usually exposed skin.
The American Cancer Society advocates that one should make sure skin is covered in clothing or sunscreen and to avoid exposure to the sun between 10 AM and 4 PM. The U.S. Surgeon General has issued a Call to Action focused on reducing ultraviolet (UV) exposure, whether from indoor UV or from the sun.
Though these recommendations, all focused on the reduction of skin cancer, are accompanied by a brief acknowledgment of the importance of vitamin D for health, they persist in urging avoidance of the sun at the precise times when vitamin D can be synthesized in the skin—the hours between 10 AM and 3 PM—and suggest that all necessary vitamin D can be obtained through food and dietary supplements.
The above recommendations are to help prevent the millions of nonmelanoma skin cancers that are recorded annually.
That notwithstanding, the sun has so many other benefits aside production of vitamin D. Exposure to the sun has shown some cardiovascular benefits, reduction of certain cancers, diabetes which could be achieved by doubling average blood concentrations of 25-hydroxyvitamin D (25(OH)D) to 40 ng/mL through a combination of sun exposure and supplements [Grant WB, 2011]
Physiological responses go beyond the production of vitamin D. When the skin is stimulated with UVA radiation, nitric oxide is released, stimulating vasodilation and lowering of blood pressure. During active exposure to UVA, diastolic blood pressure in one study fell by roughly 5 mmHg and remained lower for 30 minutes after exposure [Liu D et al, 2014].
A reduction of diastolic blood pressure by 5 mmHg decreases risk for stroke by 34% and coronary heart disease by 21% [MacMahon S et al, 1990].
Additionally, human skin produces beta-endorphin in response to UVB exposure [Slominski At et al, 2012]. These opioid peptides have the effect of increasing a feeling of well-being, relieving pain, promoting relaxation, wound healing, and cellular differentiation.
Light signals received through the eye regulate production of melatonin and serotonin for circadian rhythm control and also play a role in seasonal affective disorder [Paul KN et al, 2009].
A breastfeeding mother needs an optimum amount of vitamin D present in breast milk in order to supplement the baby. In order to fully support the infant’s need for vitamin D, the mother must have a blood concentration of cholecalciferol (vitamin D3) above 10 ng/mL, which happens only when serum 25(OH)D is above 48 ng/mL [Hollis BW et al, 1986].
Essentially, we should have moderate sun exposures in order to obtain the optimal amount of vitamin D necessary for physiological processes and protection.
Should it be an exposed skin or you can get it with clothes on?
The body produces vitamin D from direct sunlight on the skin when outdoors. It does so when ultraviolet radiations penetrate the epidermis and photolyzes provitamin D3 (7-Dehydrocholesterol) to previtamin D3 which is either converted (by isomerization) to vitamin D3 or further photolyzed to lumisterol and tachysterol in circulation.
Ideally, for this process to take place efficiently, the skin should be exposed but concerns with nonmelanoma skin cancers should limit the extent and duration of exposure. Wearing a singlet or light shirt is ok but not thick jackets and pullovers.
Which Foods Contain Vitamin D?
Some foods which supplements us with vitamin D includes ;
- oily fish – such as salmon, sardines, herring and mackerel
- red meat
- egg yolks
- fortified foods – such as some fat spreads and breakfast cereals
What are the symptoms or complications associated with deficiency of vitamin D?
May show no symptoms especially in young adults but may show as poor feeding problems, rickets or poor bones development in children and infants.
Some complications include; osteomalacia (softening of bones in adults), rickets (softening of bones in children), hypocalcemia (low blood calcium), hypophosphatemia (low blood phosphate). All of these complications will be diagnosed by a physician and managed appropriately.