As winter walks in this year, there will be lesser sunshine hours. This takes up added relevance for the old and those who suffer from osteoporosis and simialr conditions of the bone. Strictly speaking, sunshine itself is not a source of Vitamin D. However, it helps our body (skin in particular) to synthesize Vitamin D.
The epidermal layers of Stratum basale and Stratum Spinosum produce maximum amount of a particular type of a pre-vitamin D3.
Another nomenclature which may be a misfit is, Vitamin. Technically, the chemical of Vitamin D is a prohormone (or a precursor to what makes a hormone or a hormone prototype if you please).
Vitamin D is a fat-soluble vitamin that can be manufactured by the body. Vitamin D is metabolised by the liver and the kidneys and is converted to a hormone called Calcitonin. Calcitrol ensures that there is enough calcium in the blood to help form bones, teeth and maintain bone density. When ultra-violet rays shine on our skin, a cholesterol-like substance gets converted to Vitamin D and absorbed into the blood. Vitamin D is required for the metabolisation of calcium.
A light skinned person requires 15 minutes worth exposure 2-3 times a week and a darker skinned person will require a few hours longer. Vitamin D can be stored by the body. Thus stored Vitamin D from summer can come in handy during the winter months of lesser hours of sunshine. RDA for Vitamin D is fixed at 5 micrograms or mcg for women between 19 and 50 years of age, which translates to 200 IU (International Units).
Some good sources of Prohormone Vit D in the absence of regular hours of sunshine are:
Pure Cod liver oil, Salmon, Mackerel, Tuna fish, Sardines, Milk - nonfat, reduced fat, and whole, vitamin D fortified, Ready-to-eat cereals, Egg, 1 whole ( in egg yolk), Beef liver, Swiss Cheese etc
Mamta Singh is a published author, seasoned business, creative and academic writer. She is a certified fitness instructor, personal trainer & sports nutritionist through IFA, Florida USA. She is the lead writer and holds Expert Author status in many well-received health, fitness and nutrition sites.