Shedding light on vitamin D


By Laura Hsu,

IH Dietetic Intern

Vitamin D has been getting a lot of attention from the press in recent years, and you’ve likely been told at some time that you should be getting a regular dose of this “sunshine vitamin.” Why is it so important? Read on and find out!

Vitamin D is a compound that our bodies are actually capable of making if exposed to adequate sunlight. It promotes the uptake of calcium in the gut, and plays an important role in the building and strengthening of bones. Adequate vitamin D and calcium intake is essential for the prevention of osteoporosis, which in turn can reduce bone fracture risk, especially in older adults. That’s not all – research suggests that vitamin D may also play a role in fighting infections, normalizing blood pressure, and preventing autoimmune diseases.

As with most other vitamins, a certain level of vitamin D intake is needed to get the maximal benefits. For adults between the ages of 19-70 years the established Recommended Dietary Allowance (RDA) level is 600 IU (15 mcg) per day. The RDA for adults over the age of 70 is 800 IU (20 mcg) per day. The RDA for women who are pregnant or lactating is 600 IU (15 mcg) per day. The RDA level increases with age because our kidneys become less able to convert vitamin D to its active form; meaning more is needed to actually get the same results. Adults of any age should not exceed an intake of 4000 IU (100 mcg) per day, as it may result in negative health effects.

Certain segments of the population are at higher risk for vitamin D deficiency and should take extra care to make sure that they are getting enough. These include:

• Older adults – the skin’s ability to make vitamin D becomes less effective with age.

• People with limited sun exposure – those who live in northern climates, spend most of the day indoors, or consistently wear sunblock when outdoors.

• People with darker skin – the higher amounts of pigment in skin reduces skin’s ability to produce vitamin D.

• People with certain medical conditions – conditions that impair fat absorption (e.g. Crohn’s, cystic fibrosis) will affect vitamin D uptake as it is a fat-soluble vitamin.

Good sources of vitamin D include fatty fish such as salmon, tuna, mackerel and sardines, milk, and fortified soy or rice beverage. Vitamin D is widely available in supplement form, either alone or as part of a multivitamin. For more information visit Health Canada’s website or Dietitian Services at HealthLink BC’s website.