There are few dietary supplements that medical professionals recommend without hesitation! Vitamin D is an exception. Given the few food sources and the long winter months, taking a vitamin D supplement is often advisable! Update on this sunshine vitamin!
Vitamin D is essential for bone health because it facilitates the absorption of calcium and helps store it in the bones. It is also useful for the proper functioning of the immune system, muscles and nerves.
In summer, the body produces this vitamin under the influence of UVB rays from the sun. However, between October and March, the radiation is not enough to meet the body’s needs. It is therefore necessary to resort to diet and supplements.
What is the vitamin D requirement?
Vitamin D requirements vary with age.
For children and adults ages 9 to 70, the recommended amount is 600 International Units (IU) or 15 micrograms (mcg) per day.
For adults over 70, the recommended amount increases to 800 IU or 20 μg per day. These amounts include vitamin D from foods and supplements.
Vitamin D and Nutrition
When it comes to food, few foods naturally contain vitamin D. It’s found primarily in oily fish like salmon and sardines, egg yolks, and certain mushrooms. On the other hand, there are products fortified with vitamin D, such as cow’s milk, plant-based drinks (e.g. soy) and certain yoghurts. The table below lists the best sources of vitamin D.
Why Take a Vitamin D Supplement?
Since only a few foods contain vitamin D and the winter radiation is not sufficient to meet the body’s needs, supplementation is very likely. In fact, Health Canada recommends that adults over 50 take a supplement of 400 IU (10 μg) of vitamin D daily. With increasing age, the body also synthesizes less vitamin D. With the same exposure to light, a 70-year-old person produces 75% less vitamin D than a 20-year-old person. Dark-skinned people also naturally produce less vitamin D when exposed to the sun.
Osteoporosis Canada recommends that people over 50 and high-risk young adults (with osteoporosis, multiple fractures, or with a medical condition that inhibits vitamin D absorption) consume between 800 and 2,000 IU daily. The Canadian Cancer Society recommends taking 1000 IU per day because of vitamin D’s protective role in certain cancers (particularly colon and breast cancer). Not everyone metabolizes vitamin D in the same way. It is advisable to have a blood test to assess your circulating vitamin D to ensure levels exceed 50 nmol/L. This desired plasma level is primarily based on bone health, several experts recommend levels equal to or greater than 75 nmol/L given vitamin D’s role in preventing multiple diseases. To achieve the desired goal, it is preferable to give vitamin D in daily doses rather than giving intermittent high doses (eg, once a week).
Which supplement to choose?
Vitamin D supplements come in two different forms: vitamin D2, or ergocalciferol, and vitamin D3, or cholecalciferol. Both vitamins are well absorbed from the gut, but most scientific evidence indicates that vitamin D3 further increases serum levels (i.e. blood concentration) of this vitamin and maintains higher levels longer than vitamin D2.
Note that several multivitamin and mineral supplements already contain vitamin D (between 400 and 800 IU depending on the brand).
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