Vitamin D is a fat-soluble vitamin found primarily in fortified dairy products such as milk and yogurt. It exists primarily in two active forms: ergocalciferol, also known as vitamin D2 and cholecalciferol, commonly referred to as vitamin D3. The human body prefers D3 and can obtain it from both sunlight and dietary sources. Adequate levels of vitamin D3 are needed for the body to effectively use calcium. Both inadequate and excessive D3 intake can lead to bone loss as well as other significant health problems.
Recommended Intake
The National Institutes of Health recommends that those between the ages of 1 and 70 years old consume approximately 15 mcg, or 600 IU, vitamin D3 each day. This includes both pregnant and breastfeeding women as well. Infants under the age of one require only 10 mcg, or 400 IU, vitamin D3 per day. It is recommended that adults over the age of 70 consume 20 mcg, or 800 IU, vitamin D3. These values represent the amount of vitamin D3 required for proper body functioning and optimal bone health.
Tolerable Intake Level
The National Institutes of Health set tolerable intake levels to indicate the maximum amount of a nutrient that a healthy individual can consume without causing harmful effects to the body. For those over the age of 9, the tolerable upper intake level has been set at no more than 100 mcg, or 4,000 IU, per day. Infants under the age of one should consume no more than 25 to 37.5 mcg, or 1,000 to 1,500 IU, vitamin D3 each day. Children ages one to eight are to be limited to 75 mcg, or 3,000 IU vitamin D3 per day.
Dangers
The Linus Pauling Institute states that excessive vitamin D3 intake can lead to abnormally high calcium levels within the body. High blood calcium levels can result in bone loss, calcium deposits in tissues such as the heart and lungs, kidney stones, kidney damage, heart arrhythmias, nausea, vomiting, constipation, weakness, loss of appetite, confusion and weight loss. Severe symptoms are noted following daily doses in excess of 50,000 IU.
Sources
Rich dietary sources of vitamin D3 include salmon, sardines, mackerel, fortified soy and cow's milk, fortified orange juice, fortified cereals and eggs. UVB rays from the sun help to stimulate vitamin D3 development within the skin. Just 5 to 10 minutes of sun exposure, 2 to 3 times per week, can meet the vitamin D requirements of most healthy people. According to the Office of Dietary Supplements, excessive sun exposure does not result in vitamin D toxicity. Most often, toxicity occurs from excessive supplement use. Consult your doctor prior to starting vitamin supplements to determine safe intake levels to best fit your specific needs.
Member Comments