Choosing Food With Vitamin D For Your Diet
Vitamin D is sometimes called the sunshine vitamin because exposure to sunlight is generally sufficient for most people to make their own Vitamin D, using ultraviolet light and cholesterol in their skin. With calcium and phosphorous, a biologically active form Vitamin D plays an important role in healthy bones and teeth. It can also help your kidneys regulate the levels of calcium and phosphate in your blood.
The vitamin also is thought to play a role in the growth of tissues such as skin, muscles and the pancreas and in helping certain cells specialize for various bodily tasks. For example, when calcium must be removed from bones to keep up the level of this mineral in your blood, the active form of Vitamin D may help prod production of cells that can accomplish that task.
Why Worry About Vitamin D
Some people live in places where they don’t get enough sunshine to create their own Vitamin D. Or, while casual sunlight exposure can create enough Vitamin D to last through the winter, some people are unwilling or unable to go outside. A deficiency of Vitamin D in children can lead to a disease called rickets. With rickets, there are structural abnormalities of weight-bearing bones, such as the lower leg bone. Legs may become severely bowed. In adults, a deficiency of Vitamin D can lead to osteomalacia, or softening of the bones.
How Much Do You Need?
For most people under 50 years old, the government Dietary Reference Intakes guide calls for a mere 5 micrograms per day. But by age 70, most people need about 15 micrograms per day. Careful attention to diet or supplements could be needed by people who are usually shielded from sunlight, live in northern climates or areas with high atmospheric pollution or who work nights and stay inside during the day. These people could benefit from a vitamin supplement.
Foods Rich in Vitamin D
The active form of Vitamin D is found in animal products. Fish-liver oils have the highest concentration. Human milk and cow’s milk are poor sources of the vitamin, but most the milk and all infant formulas sold in the United States are fortified with it. Soy and other non-dairy milks are now being fortified as well.
Specific Vitamin D Content
One ounce of fresh raw herring provides a day’s requirement of Vitamin D, and one ounce of cooked salmon has more than half. A cup of fortified cow’s milk contains about half a day’s supply of Vitamin D. An egg yolk contains about 10 percent. One teaspoon of cod-liver oil has about double the daily recommendation for Vitamin D.
Too Much or Too Little
Too much Vitamin D can make blood levels of calcium rise. This can lead to calcification of soft tissues, such as the kidneys or lungs. The eardrums can also be calcified, which could lead to deafness. Headaches, nausea kidney stones and weakness are possible symptoms of Vitamin D intoxication, or an overdose. Infants and young children are the most vulnerable to Vitamin D overdoses. Fifty micrograms per day is the most they should get.