By Bonnie Jenkins, Advanced Natural Wellness

For much of America, winter means short, gloomy days that seem to last forever. Since I’m a sun-lover, this time of year often puts me in a funk. But along with a higher rate of seasonal depression, winter’s sunless days can also lead to a vitamin D deficiency.

We all know that vitamin D is important for building strong bones and teeth – and that too little contributes to osteoporosis. But low levels of this critical nutrient have also been linked to an increased risk of Type I diabetes, muscle aches and bone pain. More frightening, low vitamin D levels can boost the risk of cancer of the breast, colon, prostate, ovaries, esophagus and lymphatic system.

Since the half-life of vitamin D is only about three weeks, just a month of cloudy, snowy weather can leave you without adequate stores.

The Cancer Link

For the past two decades, researchers have known that almost every cell in the body contains receptors for activated vitamin D. Without enough vitamin D, cells can multiply too quickly and promote cancerous tumors.

Yet between 20 and 80 percent of all Americans have low enough levels to classify them as vitamin D deficient. And winter just makes the problem worse.

From November through March, there’s insufficient vitamin D from sunlight in most of the country north of Atlanta. This may explain, at least in part, why some studies dating back to the 1940s have found that, after adjusting for other factors, people in New England have a higher overall cancer death rate than those in sunnier climates. More recently, researchers have specifically linked a vitamin D deficiency, which can be detected with a blood test, to several non-skin cancers.

But, here’s the good news: One new DNA study by the University of Wisconsin found that supplementing with vitamin D inhibits the growth of prostate cancer cells. An earlier study by the University of North Carolina-Chapel Hill also found that vitamin D has a protective effect on breast cancer. In this study, the researchers tested the vitamin D levels of 156 women with breast cancer and compared the results with those of 184 healthy controls. Those with higher levels of serum vitamin D were almost universally cancer-free. Who was most at risk for low levels of the nutrient? White women over the age of 54.

The problems stemming from low vitamin D levels aren’t just limited to cancer. A study published in the Mayo Clinic Proceedings suggests that vitamin D deficiency may be responsible for unexplained bone and joint pain. Other research links low levels to Type 1 diabetes. Fortunately, according to Finnish scientists, supplemental vitamin D can reverse this trend. In their research, they found that people who took vitamin D supplements through adulthood were 80 percent less likely to develop Type I diabetes than their non-supplemented peers.

Test Your Levels

How do you know if you are deficient? A simple blood test can tell you.

The two most common vitamin D tests measure calcidiol (an inactive form of the nutrient) and calcitriol (the active form). The test for calcidiol (sometimes called 25-hydroxy-vitamin D) is used to assure that the body has an adequate vitamin D supply. The test for calcitriol (sometimes called 1,25 dihydroxy-vitamin D) is used to assure that the kidneys are converting enough calcidiol to the active hormone calcitriol.

It’s especially important to have your levels tested if you are taking antacids, some heart medications or anti-seizure drugs, since these drugs can decrease your vitamin D levels. Antacids may alter the levels, metabolism and availability of the nutrient. Calcium channel blockers can decrease you body’s production of vitamin D. Cholestyramine, a cholesterol-lowering drug known as a bile acid sequestrant, interferes with the absorption of vitamin D. And anti-seizure medications like Phenobarbital can speed up the vitamins’ metabolism.

One Last Thing …

Unfortunately, unless you’re eating three or four servings of salmon a week, there are essentially no foods that provide enough vitamin D to prevent a deficiency during the winter months. According to Dr. Michael Hollick, one of the top vitamin D researchers in the world, “You can’t depend on getting vitamin D from milk. Our research shows that 30 percent of the milk we tested had only 20 percent of the levels stated in the label.” In other words, you’d have to drink 10 glasses of milk or vitamin D-fortified orange juice each day to get the same amount of vitamin D you’ll find in supplements.

It’s important to take supplemental vitamin D during the winter months, especially if you are a vegetarian, since plant foods are fairly low in this nutrient. To ensure you are getting proper amounts, its wise to take a daily multivitamin containing at least 400 international units, as well as a separate vitamin D supplement with between 400 and 1,000 IU. Cod liver oil is also a super source of vitamin D.

Just don’t go overboard. Like other fat soluble vitamins, vitamin D can be toxic at high doses. The problem is more prevalent with synthetic vitamin D2, so check the label on your supplement to make sure it contains only vitamin D3.

This Just In …

One of my favorite winter spices is cinnamon. So I was thrilled to come across a new study showing that less than half a teaspoon of cinnamon daily could significantly reduce the risk factors for diabetes and cardiovascular disease in people with type 2 diabetes.

In the study, which appeared in Diabetes Care, the researchers divided a group of 60 volunteers who were not taking insulin randomly into six groups. The first group ate 1,000 mg. cinnamon per day, while the second group ate 3,000 mg. of cinnamon per day, and the third group ate 6,000 mg. of cinnamon per day. The remaining three groups were given placebo capsules corresponding in size and number to the capsules consumed by the three cinnamon-eating groups.

Among those eating the cinnamon, the researchers saw a 20 percent improvement in blood sugar, cholesterol and triglyceride levels in the volunteers eating as little as 1,000 mg. (less than half a teaspoon) of the spice a day for 40 days. But, when they looked at the groups taking the higher amounts they discovered that more wasn’t better.

So spice up your life! Add a pinch of cinnamon to your baked goods, hot cocoa, and even veggies and stews. Personally, I can’t think of a tastier way to boost your insulin sensitivity.

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References:

Bauer JA, et al. “Growth inhibition and differentiation in human prostate carcinoma cells induced by the vitamin D analog 1 alpha,24-dihydroxyvitamin D2.” Prostate. 2003;55:159-167.

Hansen CM, Binderup L, Hamberg KJ, Vitamin D and cancer: effects of 1,25(OH)2D3 and its analogs on growth control and tumorigenesis. Frontiers in Bioscience. 2001 Jul 1;6:D820-48.

Janowsky EC, et al. “Association between low levels of 1,25-dihydroxyvitamin D and breast cancer risk.” Public Health and Nutrition. 1999;2:283-291.

Kahn A, et al. “Cinnamon Improves Glucose and Lipids of People With Type 2 Diabetes.” Diabetes Care. 2003; 26:3215-3218.