Vitamin D, which is produced when ultraviolet sunlight hits the skin, helps the body absorb calcium, leading to stronger bones and the prevention of brittle bone diseases. More recently, according to "The New York Times," vitamin D deficiency has been linked to immune disorders that can cause inflammation, which in turn can lead to swelling. Because the vitamin is naturally present in so few foods, and wearing sunscreen can block cells from getting sufficient amounts of sunlight, vitamin D deficiency has become a global problem.
The classic symptoms of vitamin D deficiency is rickets in children and osteomalacia in adults. Rickets can cause skeletal deformities, such as thickened wrists and ankles. It can also cause muscle weakness and pain in the back, pelvis and legs. Osteomalacia is a bone condition that causes softened bones and an aching pain in the lower back, pelvis, hips and legs.
In recent years, experts have discovered more far-reaching effects of vitamin D deficiency. In 2009, researchers from the University of Missouri-Columbia found that insufficient levels of vitamin D are associated with inflammation, an immune system response that can cause fluid buildup and swelling. This study has contributed to the 2010 decision by the Institute of Medicine to increase vitamin D intake recommendations for all Americans.
Recommended Daily Allowance
In effort to reduce the incidence of rickets in children, the U.S. Food and Drug Administration started the vitamin D milk fortification program in the 1930s. Today, you can get vitamin D in orange juice, cereal and a variety of dairy products. If you don't get enough vitamin D from your diet or through direct sunlight, the ODS suggests taking a supplement. The recommended daily allowance, or RDA, for kids and adults is 15 micrograms, or 600 international units, or IU, daily. The RDA for seniors over the age of 70 is 20 micrograms, or 800 IU daily.
Vitamin D toxicity is a condition that occurs by taking too much vitamin D for a prolonged period of time. Due to a built-in mechanism in the body, it's impossible to get too much of the vitamin from diet or sunshine. In two documented cases of vitamin D toxicity, patients reported taking more than 1,000 micrograms, or 40,000 IU daily. Neither case resulted in death. Symptoms include nausea, vomiting, loss of appetite, weakness, weight loss and heartbeat abnormalities.