Why shorter days call for a dose of Vitamin D
It is officially winter in our household because I have pulled out the vitamin D supplements. My daughter was too young last winter to remember that she added a vitamin to her morning routine, but my boys knew what it signalled.
Instead of gobbling down the vitamins without query as they did last winter, my boys fired questions my way as to why they had to take them. I guess this is what teenagers do: They question their parents about everything, even the things they have taken for granted for more than a decade.
I’m OK with their questions. I certainly don’t want them blindly taking vitamins or pills under any other circumstances, even if prescribed by a doctor. Asking questions is good. Demanding explanations is good. Understanding dosages is good.
So, boys, here are the reasons I want you to take vitamin D in the winter, even though we should get all of our other nutrients from whole foods.
Our bodies naturally derive vitamin D from two main sources: sunlight and food. In the winter, there is no way you boys get enough sunlight on your bare skin. The sun is low, the days are short, long sleeves and gloves prevail, and you guys, like almost everyone else in the winter, spend a majority of your day inside. Also, like most kids your age (and most adults for that matter), you do not eat enough of the foods that are naturally high in vitamin D: fatty fish such as mackerel, herring and salmon, and cod liver oil. Although many brands of milk and orange juice are fortified with vitamin D, it is still almost impossible to derive enough of it solely from food. Why is vitamin D important? Vitamin D is not actually a vitamin but rather a group of hormones. You may be surprised that I am suggesting we bring extra hormones into our house, but like all hormones, these have some pretty important jobs. They help the body absorb nutrients such as calcium, iron, magnesium and zinc. This is why vitamin D is added to calciumrich milk. Studies show that only 10 to 15 per cent of calcium in food is absorbed without vitamin D.
If you boys want to fight off colds this winter so you don’t miss any sports games or weekend fun, vitamin D can help boost your immune system. If you would like strong, healthy bones, vitamin D is king. If you don’t want your heart to putter out at an early age or your mind to deteriorate, look to vitamin D. It is also shown to prevent cancer by regulating cellular growth.
The current recommended daily allowance for individuals ages 1 to 70 is 600 IU, or international units, but more recent research at the Boston University School of Medicine recommends up to 2,000 IU. Other studies recommend even higher levels for optimal health. The confusion around the ideal daily allowance prompted a 2010 large-scale study at a Boston affiliate of Harvard University to investigate whether vitamin D can help prevent cancer, heart disease, stroke and other chronic conditions in more than 25,000 American men and women. The study is expected to wrap up later this year.
Because one glass of milk provides just 100 IU of vitamin D, a piece of salmon offers 360 IU and an egg yolk under 50 IU, even the lowest recommendation of 600 IU a day is hard for most children to attain without regular sun exposure. No wonder so many studies show a vast number of kids in the United States, especially adolescents and those living in northern states, are deficient. So until the spring comes, the sun shines steadily, and you guys get off the indoor basketball court and onto the outdoor baseball field, a vitamin D supplement will join us for breakfast each morning.