The well-known health recommendation that individuals should get at least 15 minutes of sunlight a day may have far-reaching implications. The processes by which the human body manufactures vitamin D from cholesterol is initiated from the action of sunlight on the skin. Vitamin D is an important nutrient, and many people may be deficient in this vitamin. While deficiency symptoms do include fatigue and depression, nausea is a symptom of a vitamin toxicity caused by excess vitamin intake.
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A Worldwide Deficiency
Vitamin D deficiency is becoming increasingly important on a global scale as more information and studies reveal vitamin D has a greater impact on fighting a broad range of diseases than was once thought. The Harvard School of Public Nutrition reports that an estimated one billion people have inadequate levels of vitamin D in their body. This affects individuals of all ages and ethnic groups, including people in the Western world, where fortified food and vitamin supplements are readily available.
Function of Vitamin D
Vitamin D helps the body maintain healthy levels of calcium and phosphorus in the blood. It's also important for building and maintaining strong bones because it helps the body absorb calcium. Its role in regulating normal cell differentiation and proliferation suggest it may help prevent some cancers. According to MayoClinic.com, recent research also suggests vitamin D may protect against osteoporosis, hypertension, cancer and some autoimmune diseases.
Vitamin D Deficiency
The individual symptoms of vitamin D deficiency may include muscle pain, weak bones, fatigue, depression, mood swings and sleep irregularities. Individuals with intestinal problems such as Crohn's disease or irritable bowel syndrome may be deficient in vitamin D, because they cannot absorb the nutrient adequately.
Symptoms of Overdose
Because it is a fat-soluble vitamin, ingesting too much vitamin D can lead to toxicity. Nausea is a common sign of a vitamin overdose. In extremely high doses, vitamin D can be dangerous and even cause death. According to the Harvard School of Public Health, extremely high doses of vitamin D would be in the form of hundreds of thousands of IUs. You will not overdose from foods containing vitamin D or fortified vitamin D foods because the doses are not high enough. For example, one cup of orange juice fortified with vitamin D contains approximately 100 IUs. You would have to drink thousands of cups of orange juice in a day to reach dangerous levels. You will also not overdose from being in the sun for too long, because your body will not produce excessive amounts of vitamin D.
Daily Value Recommendations
The current recommendations expressed by the Institute of Medicine is for individuals over age 2 and below age 50 to consume 200 IU of vitamin D daily. The recommendation increases after age 50.
According to the Harvard School of Public Health and MayoClinic.com, the current recommendation is expected to increase as strong evidence shows optimum intake levels are higher. They estimate the recommendation will increase to 1,000 to 2,000 IU for people over 2 years old.