There has been a lot of talk lately, especially by those living in our cold northern climate, about vitamin D and the importance of ensuring our levels are where they should be. Our bodies absorb vitamin D primarily from the sun. In fact, full body sun exposure for 15 minutes is the equivalent of an oral dose of 10,000 IU vitamin D for some people. The issue is, however, the farther north that we live, the less sun we are exposed to on a daily basis during winter months. When we do go outside, our skin is completely covered to avoid frost bite! And, even during summer months, the use of both sunglasses and sunscreen to help prevent skin cancer blocks vitamin D from being absorbed through the skin. So, as a result, our levels drop drastically.
Aside from getting vitamin D from exposure to sunlight, we can also get a small amount from our diets, mostly through fortification in milk, orange juice, and some cereals. Very few foods provide vitamin D naturally; wild cooked salmon, mackerel and tuna are a few of the best sources.
In a comprehensive survey conducted by Statistics Canada, it was found that two-thirds of the population has vitamin D levels below the amounts that research is associating with reduced risk of chronic diseases such as cancer. One in 10, or more than three million Canadians, have such low readings that they don’t have enough for good bone health. About 4 per cent have so little vitamin D that they’re at risk for rickets, a debilitating childhood bone disease.
What good is vitamin D?
Vitamin D is a fat-soluble vitamin needed by the body to help maintain normal blood levels of calcium and phosphorus. By assisting the body with calcium absorption, vitamin D helps to create and maintain strong bones. Without adequate levels of vitamin D, bones can become thin, brittle, and misshapen.
Exciting new research shows that benefits of vitamin D go far beyond bone health. Here are just a few of the very important benefits that are being uncovered:
- plays an important role in maintaining a healthy immune system and reduces the spread and reproduction of cancer cells, especially for prostate, breast and colon cancer;
- decreases hypertension;
- slows the progression of osteoarthritis;
- decreases the prevalence of multiple sclerosis
Here’s a great link to read about studies on prostate, breast and colon cancer. It is remarkable to see:
- women with the highest blood levels of the active form of vitamin D had the lowest risk of breast cancer
- the level of vitamin D in the blood associated with a 50% reduction in risk of breast cancer could be maintained by taking 2000 IU of vitamin D3 daily plus spending as little as 10-15 minutes a day in the sun
- men with the highest level of vitamin D had significantly lower overall risk (45%) of prostate cancer, including aggressive prostate cancer
- Vitamin D is a protective factor against colon cancer – as there is a significantly lower risk of advanced cancerous lesions among men with the highest vitamin D intake
These findings highlight the importance of achieving optimum levels of vitamin D.
So, how much do we need?
So now that we know we should take it, how much do we really need? It all depends on if you are young or old, how much you weigh, the colour of your skin, where you live, if you enjoy the sunshine, etc.
One of the safest and most convenient ways to get adequate amounts of vitamin D is to take a multivitamin/mineral supplement and/or a calcium supplement with added vitamin D. And, it is very inexpensive. It just makes sense to take a vitamin D supplement daily.
Health Canada’s daily recommended intakes (RDAs) for vitamin D, updated in 2011, are 400 international units (IU) for infants, 600 IU for children aged one to adults aged 70, and 800 IU for adults over 70. Health Canada’s safe upper limit is 4,000 IU per day.
Osteoporosis Canada advises healthy adults aged 19-50 consume 400-1,000 IU daily, and those over 50, or younger adults at high risk, get 800-2,000 IU daily. The organization advises year-round vitamin D supplementation for all Canadian adults. However, it really does vary between individuals.
A Globe and Mail health column reports that those loading up on vitamin D with the hope of reducing cancer risks or warding off heart attacks can be harmful, and that you can get too much of a good thing. They go on to say that “while vitamin D toxicity is unlikely at daily intakes below 10,000 IU, evidence suggests that some people are more sensitive to the adverse effects of too much vitamin D”.
To find out where your vitamin D levels are, talk to your doctor about getting tested. The most accurate way to measure how much vitamin D is in your body is the 25-hydroxy vitamin D blood test.
And a last important point about vitamin D supplements. The purity of your supplement will determine how much you can take. Look for a supplement with the most active form of vitamin D (Vitamin D3) also known as cholecalciferol.
So, as we persevere the cold and cloudy days of February and March, give your body a dose of sunshine and load up on your vitamin D.
Lisa George, R.H.N., is owner of Creating Healthy Habits, a holistic nutrition consulting business based in Almonte. Contact her for questions on diet, supplementation and lifestyle.