Google “reasons to take vitamin D” and you’ll be hit by a flood of things it’s supposed to be good for. They range from diabetes to weight loss, and some of these uses have stronger evidence and studies behind them than others. We won’t try to settle any debates about vitamin D in this article. We will, however, give you five of the most important things to know about this vital nutrient.
- The history of vitamin D
It’s said that vitamin D must be unbelievably important to human health, since our body actually produces it when exposed to sunshine. When the majority of humankind stopped farming and working in the fields, they spent more time indoors in factories, schools, and other buildings. That’s when we began to see a problem with rickets, a childhood bone disease. Prevalence was highest in northern climates, especially in the winter months.
Scientists noticed that certain populations whose diets included more cod liver oil (which is rich in vitamin D) had very low incidence of rickets. In the early 1920s the supplementation of vitamin D in the diet started, and by 1945 rickets in the U.S. had been virtually eliminated.
- Vitamin D can build up, but many people are still deficient
Vitamin D is a fat-soluble vitamin, meaning it tends to build up in the body, and it can be toxic at very high levels. My family doctor told me she believes this is why many doctors are arguably a bit too conservative in recommending vitamin D. While guidelines and doctors’ recommendations have been relatively low in the past, since 2009 articles and studies have been published suggesting that most Americans are Vitamin D deficient.
- Vitamin D is important to bone health
These days, the relationship between calcium and bone health seems to be common knowledge, especially for women. However, it’s often overlooked that without vitamin D, dietary calcium won’t be absorbed properly. Parents of growing children and people with or at risk for osteoporosis should be especially aware of this. I give my 2 ½ year old son and my 8 month old daughter each 400IU daily. Carlson makes a liquid that is easy to drop in their milk, formula, or right in their mouths.
- Vitamin D can be good for depression / winter blues
If you live in a place with cold winters, your vitamin D intake from the sun probably decreases drastically in the winter months because you spend more time indoors, and covered in warm winter clothes. The body creates its own vitamin D, but only when exposed to UVB light – meaning you can hardly create any during those dark, cold days of the year. Winter blues, or Seasonal Affective Disorder (SAD) have been shown to improve with Vitamin D supplementation.
Perhaps you live in place where there’s loads of sunshine year round, but if you’re one of the many people using sunscreen, you’re still blocking UVB rays that enable vitamin D production in the body. Increased awareness about the importance of sunscreen is great, but blocking those UVB rays will also block absorption of Vitamin D.
- Vitamin D can prevent the flu
Did you ever wonder why winter is the flu season? During the winter, people spend more time indoors with their windows sealed, so they are more likely to breathe the same air as someone who has contracted the virus. Influenza also seems to survive and propagate much better in cold, dry air. Additionally, vitamin D levels tend to dip in the winter – which can decrease our ability to fend off the virus. This adds up to a perfect flu-storm in winter months- meaning that cold weather might be a great time to reach for a D supplement.
Of course there’s more to know about vitamin D, and research on it is being published at a steady clip. We’re always interested in how people are using supplements and what effects they’ve experienced. Are you taking vitamin D? Share your thoughts below!