Updated: Jan 9
You may know vitamin D as "The Sunshine Vitamin."
When your skin is exposed to the sun's UVB rays, 7-dehydrocholesterol - the inactive form of vitamin D already present in your skin - is converted to cholecalciferol - the active form of vitamin D (or, "vitamin D3).
But this is dependent on several factors:
Time of day
Distance between you and the sun (as in, the season or latitude); and,
The pigment of your skin
Vitamin D deficiency is an issue for an estimated 1 billion people world-wide.
That even includes folks who live in sunny climates! Protecting skin from the sun's rays by using clothing or sun screen prevents the conversion of 7-dehydrocholesterol to D3. But low vitamin D status is especially common for folks living in the northern hemisphere (a latitude greater than 35 degrees), as those UVB rays are further away for greater periods of time.
It is highly likely your vitamin D is low if:
You are NOT supplementing at least 800 IU vitamin D daily, AND
You live in the northern hemisphere
If you're answering yes to both of those points, and you're experiencing:
Muscle or bone pain
Frequent respiratory infections
Schedule some blood work.
With optimal levels of vitamin D (at least 30-60 ng per mL) your body reaps so many benefits including the following:
Greater bone density by increasing your body's absorption of calcium and phosphorous. This minimizes the risk for osteomalacia, osteoporosis; thus reduces the risk for fractures. Better absorption of calcium and phosphorous also supports normal functioning of the parathyroid gland. The parathyroid gland plays a part in bone development, and muscle strength.
Stronger immune system, specifically reduced risk for respiratory illnesses.
Reduced risk for cancer by destroying malignant cells.
Reduced risk for type 2 diabetes by playing a part in controlling blood sugars and sensitizing cells to insulin.
Reduced risk for high blood pressure, depression, multiple sclerosis, Chron's disease, and schizophrenia.
Supports brain development in utero, and brain function later in life.
Fascinating vitamin D plays a role in all of that!
Unfortunately, vitamin D is a tough one to come by naturally in food.
Fatty fish like salmon, sardines and tuna are excellent natural sources. Egg yolks naturally contain a little vitamin D as well. Milks, both dairy and non-dairy, are fortified. But that's about it! If you eat fish every day, drink about 24 fl. oz. milk containing fat, or eat about 10 eggs a day, then it's POSSIBLE your vitamin D levels are normal. But PLEASE note: these are in no way recommendations.
Active Vitamin D3 is utilized by every system in the body. Without enough available, bone density is at risk, immune system can weaken, and the risk for various diseases increases, including cancer, type 2 diabetes and depression. Levels below 30 ng/mL require supplementation. Discussing a treatment plan with a healthcare practitioner you trust is highly recommended.
The information in this article is designed for educational purposes only and is not intended to be a substitute for informed medical advice or care. This information should not be used to diagnose or treat any health problems or illnesses without consulting a doctor. Consult with a health care practitioner before relying on any information in this article or on this website. If you're interested in making dietary changes, guidance from a nutrition expert is highly recommended. Please Contact us or review our Nutrition & Wellness Services.
Nutrition & Wellness Services
Holick, MF. Vitamin D Deficiency. The New England Journal of Medicine. 2007; 357:266-281
The George Metelijan Foundation. Vitamin D. The World's Healthiest Foods. Accessed January 2020.