Unless you’re supplementing daily with vitamin D, it’s likely you are deficient and don’t even know it. Up to three in every four people tested are low in this vitamin. What’s the risk?
Until recently, vitamin D’s sole job was to support calcium absorption and deposition into bone, thus lowering osteoporosis risk. This role is now considered the tip of the nutritional iceberg.
Every cell in your body has receptors for vitamin D, which means every cell, tissue, organ, and system, from the top of your head to the tip of your toes, needs the vitamin. It’s no wonder research shows that vitamin D might aid the body in muscle weakness, gum disease, diabetes, insulin resistance, hearing and vision loss, arthritis, multiple sclerosis, hypertension and depression, among other health conditions. It also supports pregnancy outcome and reduces the incidence of falls by up to 60 percent in seniors, while a deficiency can mimic symptoms of fibromyalgia. Preliminary studies also show a possible link between low vitamin D intake and amyotrophic lateral sclerosis (ALS), Parkinson’s disease and more.
How could one vitamin affect so many health conditions? Vitamin D is not only a vitamin.
It also acts somewhat like a hormone, since our bodies can make it when exposed to ultraviolet B (UVB) rays in sunshine. Yet, even though our bodies can synthesize vitamin D, many people are deficient. Four factors affect how well and how much vitamin D you make, and therefore, whether you are at risk for deficiency:
- Age: A person’s ability to manufacture vitamin D decreases with each passing decade. By the time people enter their senior years, their bodies make as little as 40 percent of the vitamin D made in childhood.
- Location: People living north of the latitude running generally through Los Angeles and Atlanta typically are sun-deprived and, consequently, often low in vitamin D, especially during Fall and Winter.
- Skin Color: Melanin is the pigment that gives skin its color. The high melanin content in darker skin acts like a UV light screen, reducing the skin’s ability to produce vitamin D from sunlight. Older adults with brown to black skin are at a higher risk of vitamin D deficiency.
- Sunscreen Lotion: Sunscreen blocks harmful UV rays that cause skin damage. That’s a good thing. But, sunscreen lotions and creams also block the skin’s ability to make vitamin D. People who lavishly use sunscreen can develop a deficiency, even when out in the sun. It is recommended to use sunscreen lotion as directed by the manufacturer or to contact your health care provider.
Vitamin D at chronic high doses can have adverse effects. In the U.S., the following safe intake limits are:
- 600 I.U.s* for ages 1- to 70-years-old, pregnant and breast-feeding women
- 800 I.U.s* for ages more than 70-years-old
Some foods are fortified with vitamin D, such as milk and some yogurt, soymilk, orange juice, and cereals. The vitamin also is found in egg yolk and fatty fish, such as wild salmon (farmed salmon has considerably less of the vitamin). It would require many servings daily to get the recommended amounts.
Your best bet is to include several servings daily of vitamin D-fortified foods and fill in the gaps by taking a supplement. The older you are, the higher the dose. Consult your physician before taking daily and ask to get tested. This is one nutrient that can be measured in blood. You want a blood level of at least 30 ng/millimeter. The best time of year for a blood test is in the Fall or early Winter, such as November, when a deficiency of vitamin D is most pronounced. Ask for a test of 25-hydroxy vitamin D, not 1,25-dihydroxy vitamin D, which can produce misleading results**.
It can take several months to “fill up the tank” if you find you are low in vitamin D, so stick with your supplements and repeat the blood test every so often to check how you’re doing. This is one vitamin that has far too many benefits to ignore!
*I.U. stands for International Unit. (200 I.U.s is equivalent to 5 micrograms)
**Why does 1,25 dihydroxyvitamin D produce misleading results? Here is an explanation and the study it came from:
Recently, the accuracies of many commercially available immunoassays for Vitamin D have been questioned. Liquid chromatography tandem mass spectrometry (LC- MS/MS) has been shown to facilitate accurate separation and quantification of the major circulating metabolite 25-hydroxyvitamin-D3 (25OHD3) and 25-hydroxyvitamin-D2 (25OHD2) collectively termed as 25OHD. However, among other interferents, this method may be compromised by overlapping peaks and identical masses of epimers and isobars, resulting in inaccuracies in circulating 25OHD measurements. The aim of this study was to develop a novel LC-MS/MS method that can accurately identify and quantitate 25OHD3 and 25OHD2 through chromatographic separation of 25OHD from its epimers and isobars.