A question I commonly get asked this time of year is ‘Do I stop taking my vitamin D supplement now that it’s summer?’
Vitamin D has been in the news a lot over the last couple of years. It's proven to be important in the formation of bone and prevention of osteoporosis, but speculation has it that low levels may be linked (results pending) to many different health conditions including high blood pressure, cancer (colorectal, prostate, breast and lung cancers), multiple sclerosis, rheumatoid arthritis, Crohn’s disease, the flu, and mood disorders like depression.
Vitamin D is the ‘Sunshine Vitamin’ because when our skin is exposed to direct sunlight, our bodies can produce 10,000 to 20,000 International Units (IU) of vitamin D. Without direct sunlight, we can get a small amount of vitamin D from our diets, but choices are limited and the amount we can consume is small.
- 1 cup of milk (fortified) - 100 IU
- 2 canned sardines - 60 IU
- 1 large egg with yolk - 20 to 40 IU
- 3 oz beef liver - 42 IU
- 3 oz cooked salmon - 447 IU
- 3 oz canned white tuna - 84 IU
Because Canadians are living at a northern latitude, vitamin D deficiency is relatively common and it is especially prevalent in older adults. Direct sunlight isn’t available all year and when it is, we often cover up or wear sunscreen. As we age we also lose receptor sites in our skin which convert sunlight to vitamin D. Older adults may also have difficulties converting dietary vitamin D into a useable form.
To complicate the issue there is the understandable worry around exposing skin to the sun and skin cancer.
So no one has to rely on the sun for vitamin D, Health Canada gives us the following Recommended Dietary Allowance (RDA) per day.
Infants 0 to 12 months - 400 IU
Children and adults - 600 IU
Adults 70 years old or older - 800 IU
However, many health care providers feel these numbers should be higher and recommend adults receive 1,000 to 2,000 IU of vitamin D daily for disease prevention. Most vitamin D supplements are indeed sold in units of 1000 IU.
Taking a vitamin D supplement all year therefore may be the right choice for you. If you are hesitant talk to your doctor, a blood test can check your vitamin D levels.