Have you seen the Sun today? Most American’s are lacking this vital nutrient.
Vitamin D, a fat-soluble vitamin named cholecalciferol when in it’s active D3 form is made when skin is exposed to ultraviolet-B radiation from sunlight. It can also be consumed from the diet when UVB radiation is insufficient for D3 synthesis by the skin. Vitamin D is biologically inactive, it must be metabolized to it’s active forms. Vitamin D first comes into being by being synthesized in the skin’s epidermis or it can be consumed. Once it comes into being it enters the blood and goes to the liver where it changes to 25-hydroxyvitamin D. Then it travels to the kidney where it is altered to 1,25-dihydroxyvitmain D (the most potent form), most physiological effects of Vitamin D are due to this form.
Vitamin D’s actions are completed through a vitamin D receptor; more than 50 genes in tissues throughout the body are known to be regulated by 1,25 hydroxyvitamin D. Vitamin D plays a role in maintaining serum calcium levels. It normalizes calcium in the blood by increasing intestinal absorption or reabsorption from the kidneys; it may takes calcium from bone if blood calcium is too low. Active vitamin D inhibits cell proliferation and makes cells differentiate, both protect against cancerous cell development. Vitamin D is also an immune system modulator.
Modern Americans are often low in vitamin D from any of the following factors: breast milk doesn’t contain vitamin D, dark skin decreases synthesis of Vitamin D, aging reduces capacity to make vitamin D, sunscreen and covering exposed skin blocks synthesis, it’s fat soluble so fat malabsorption syndromes impair absorption, inflammatory bowel disease hinders absorption, obesity increase risk of deficiency.
Vitamin D is important for gene regulation, calcium balance, cell differentiation, Immunity, Insulin secretion, Blood pressure regulation. Deficiency can result in weak or deformed bones (osteopenia, osteoporosis, osteomalacia, rickets).
The take home message is get tested for vitamin D3, find out what your levels are so you may properly supplement. A little bit of sun light is not a bad thing (10-15 minutes is recommended daily without any sunscreen which blocks the UVB), just don’t stay out too long and get burned! Osteoporosis is common with aging, vitamin D3 helps protect bone health and is correlated with less risk of hip fracture in postmenopausal women. Healthy vitamin D3 levels decreases autoimmune disease and cancer risks including colorectal cancer, breast cancer, prostate cancer.
Vitamin D toxicity is a risk. Lab testing and doctor supervision is recommended. Too high vitamin D levels exacerbates bone loss and causes calcification of the heart and kidneys.