Your body must have Vitamin D to absorb calcium and promote bone growth. Too little Vitamin D results in soft bones in children (rickets) and fragile, misshapen bones in adults (osteomalacia). You also need Vitamin D for other important body functions.
Here are a few things you may not know about Vitamin D:
1. Vitamin D helps regulate the immune system and the neuromuscular system.
2. Vitamin D is really not a vitamin. Vitamins are special nutrients that the body needs but cannot make, so they must be obtained from what we eat or by supplements. Because our bodies can make Vitamin D in our skin when it is exposed to good sunlight, Vitamin D is considered a hormone.
3. Not many foods naturally contain Vitamin D — it is found in substantial levels only in fish.
Some foods have Vitamin D added to them (“fortification”). For example, milk is fortified, but an 8-ounce glass of milk provides only 100 IU of Vitamin D. Some other foods, like breakfast cereal, are fortified, but at very low levels. Eggs can have small amounts of Vitamin D if the chicken was fed the vitamin.
Other dairy products — such as yogurt and cheese — are typically not fortified with Vitamin D.
How did we learn about Vitamin D and its importance?
When our ancestors stopped working in the fields and entered factories or schools, rickets began to be a problem—in fact, it was commonly seen during winter months, especially in northern locations.
In about 1920, people noticed that children who took cod liver oil rarely got rickets. This led to the discovery of Vitamin D and the beginning of Vitamin D supplementation of the diet.
Why Is there a new focus on Vitamin D today?
Recent research has stressed the importance of Vitamin D — not just for good bone health, but also for possibly preventing chronic disease when we are older. Yet, many children today are not getting enough Vitamin D.
There are several reasons children today do not get enough Vitamin D. An important one is that very few foods contain substantial levels of the vitamin. Even the healthiest of diets will probably not provide a child with adequate Vitamin D.
Changes in lifestyle have also played a part. Several aspects of modern-day childhood impact Vitamin D intake:
- Children today spend hours in front of a computer or a television, rather than playing outdoors.
- Few children walk to school on a regular basis.
- Many popular sports, such as basketball, volleyball, and gymnastics, are indoor sports.
- Milk intake by children has steadily decreased in favour of soda or juice.
How much Vitamin D do we need?
Vitamin D is measured in units called “International Units,” or IUs. According to the Institute of Medicine—Food and Nutrition Board, and the National Institutes of Health—Office of Dietary Supplements, the Recommended Daily Allowances for Vitamin D among children is:
- 400 IU/day for children aged 0-12 months
- 600 IU/day for children aged 1-18 years
This is the amount that seems to prevent rickets, not the amount that will result in the healthiest bones.
Recent research supports that children over age 5, adolescents, and adults needs at least 1000 IU per day for good health — depending on age, weight, and growth. Indeed, many people need much more than 1000 IU to keep Vitamin D levels in a good range.
How do I make sure my child gets enough Vitamin D?
Taking a Vitamin D supplement is the most effective way for your child to get 1000 IU of Vitamin D every day. To get Vitamin D from food, your child would need to eat fish every day and drink 10 glasses of Vitamin D fortified milk each day. Most children do not do this, so the most practical way for children to get enough Vitamin D is to take a supplement, at least in the winter time.
Can we overdo Vitamin D?
Our skin cannot make too much Vitamin D — it stops when there is enough in the blood — but it is possible to overdose on Vitamin D supplements.
Because too much Vitamin D can be harmful, doses greater than 2000 IU/day should be taken cautiously, as advised by your doctor and based upon the results of blood tests.
Does Vitamin D do more than help us absorb calcium?
Vitamin D is important for good muscle health. People with very low Vitamin D blood levels may be more likely to experience muscle cramps, bone, or joint pain.
Studies suggest that older people who take Vitamin D seem to fall less often, probably due to better muscle function.
Vitamin D is very important in many aspects of our health. Children and adults alike should eat Vitamin D-rich foods, such as milk and fish, and take Vitamin D supplements to enjoy good bone health!