Vitamin D plays an important part in preventing bone fractures and osteoporosis. Osteoporosis, or low bone density, affects or may affect more than 25 million adults in the United States, the National Institutes of Health reports. Children with a vitamin D deficiency can develop rickets, the childhood form of osteomalacia, or soft bones. Many people require between 400 and 1,000 International Units of vitamin D a day to maintain bone strength and replacement, the University of Washington reports.
Definition
Vitamin D is a fat-soluble vitamin, meaning that your body stores excess amounts of vitamin D rather than eliminating it in urine. Vitamin D occurs naturally in a few foods, such as fish and eggs. Many commercially available foods, such as milk, also have vitamin D added to them. In addition to food sources, your body can manufacture vitamin D in your skin if you get 10 minutes a day of sun exposure.
Purpose
Vitamin D assists in the absorption of calcium from the intestine. Vitamin D and the parathyroid glands work together to maintain adequate absorption of calcium and also to release calcium from your bones when blood levels of this element fall too low. Calcium is essential for building dense bone and preventing fractures.
Risk Factors
Several populations have an increased risk of vitamin D deficiency and development of bone fractures or soft bones. Breast milk contains very little vitamin D, so breastfed babies require vitamin D supplementation starting within the first two months of life, MayoClinic.com states. The recommended daily intake for infants is 200 IU, the Linus Pauling Institutes reports. People with diseases such as cystic fibrosis that interfere with absorption of nutrients, people who have had gastric bypass surgery, dark-skinned people who may not absorb sunlight well, overweight people, the elderly and people who don't get enough sun exposure may also fall short on vitamin D requirements, placing them at additional risk for fractures.
Research
The Linus Pauling Institute reported that an 18-year study of 72,000 postmenopausal women found that those who took in at least 600 IU of vitamin D daily reduced their risk of hip fracture by 37 percent. An analysis of several clinical trials found that taking 700 to 800 IU of vitamin D daily decreased the risk of hip fractures in older adults by 26 percent and the risk of vertebral fractures by 23 percent.
Warning
Taking excess amounts of vitamin D can lead to hypercalcemia, too much calcium in your blood. Hypercalcemia doesn't add protection to your bones and can actually cause bone loss instead. Other symptoms include weakness, fatigue, abnormal heart rhythms, confusion, nausea, vomiting, unsteadiness, dizziness and kidney damage. Take only the amount of vitamin D prescribed by your medical practitioner and report any symptoms promptly.
