Eat a Diet Rich in Vitamin D
]]> Vitamin D]]> is a fat-soluble vitamin. It helps the body absorb calcium and plays a crucial role in the growth and maintenance of strong, healthy bones. In children, adequate vitamin D is important for the prevention of ]]>rickets]]> . And in adults, vitamin D deficiency has been associated with a greater incidence of ]]>hip fracture]]> . Increased intakes of vitamin D, on the other hand, have been associated with less bone loss in older women. This has led some researchers to believe that vitamin D supplementation may help prevent fractures resulting from ]]>osteoporosis]]> .
Recent research suggests that vitamin D may play a role in a number of other conditions, as well. More research is needed to confirm the findings, though. For example, vitamin D deficiency has been related to muscle weakness and pain. In one study, patients with low back pain received high doses of vitamin D for three months, which resulted in significant improvement of their symptoms.
Also, there is some research to suggest that this supplement may play a role in cancer prevention. Vitamin D receptors have been found in breast and prostate tissue, implying that such a link does exist. Additionally, there is some evidence hinting that low levels may play a role in the development of ]]>high blood pressure]]> . There is also preliminary research suggesting that long-term vitamin D supplementation decreases the risk of ]]>multiple sclerosis]]>. Recent research also suggests that lower levels of vitamin D are associated with a greater likelihood of developing upper respiratory infections, such as the ]]>common cold]]> and ]]>flu]]>.
People who are at a high risk for vitamin D deficiencies are the elderly, those who get minimal sun exposure, or those who use sunscreen whenever outside. Also, people with conditions that may impact intestinal absorption, such as ]]>Crohn's disease]]> , are at risk.
In addition, infants that are breastfed only may require additional supplementation with vitamin D starting within the first days of life. While the dietary reference intakes for vitamin D remain the same, the American Academy of Pediatrics recently doubled the recommended daily dose of vitamin D for infants, children, and adolescents from 200 to 400 IU per day. Requirements for pregnant women are the same as for healthy adults. Some believe that pregnant mothers should take more vitamin D than recommended. However, since there is an increased risk of vitamin D toxicity with increased intake, such recommendations need to be discussed individually with a doctor.
According to most authorities, the recommended intakes for vitamin D are:
|Age (years)||]]>Adequate Intake]]>|
Sources of Vitamin D
Vitamin D is found in some foods, but the main sources are milk and sunlight. The ultraviolet rays of the sun react with cholesterol present on the skin and create previtamin D3. This compound goes through a series of reactions involving the kidneys and the liver, and the final product is vitamin D.
Most people's bodies can manufacture enough vitamin D with 10 to 15 minutes of sun exposure two to three times per week. However, this synthesis is affected by age, season, latitude, time of day, cloud cover, smog, and skin pigmentation.
Other food sources of vitamin D include:
Vitamin D content
|Cod liver oil||1 tablespoon||1,360|
|Salmon, cooked||3½ ounces||360|
|Mackerel, cooked||3½ ounces||345|
|Sardines, canned in oil||3½ ounces||270|
|Milk, vitamin D fortified||1 cup||98|
|Margarine, fortified||1 tablespoon||60|
|Liver, beef, cooked||3½ ounces||30|
Tips for Increasing Your Vitamin D Intake
- If you take a vitamin supplement, make sure it contains vitamin D.
- Eat fish, especially fatty fish such as salmon and mackerel, 2-3 times per week.
- Drink vitamin D-fortified milk.
- Get sun exposure, but be careful to watch for ]]>sunburn]]>. Sunlight is a major cause of ]]>skin cancer]]> . Fifteen summer minutes of sun exposure to face and arms will allow most persons to synthesize adequate vitamin D and minimize the risk of skin damage. In most northern climates, winter sun is too obstructed and low in the sky to allow vitamin D synthesis in the skin. Also, few people go outside without covering much of their body with clothes. In the winter, vitamin D supplements or multiple servings of milk and fatty fish are necessary for good health.
International Food Information Council
National Coffee Association of USA
Canada's Food Guide
Dietitians of Canada
Bowes and Church's Food Values of Portions Commonly Used. 17th ed. Lippincott Williams & Wilkins; 1998.
Dietary supplement fact sheet: vitamin D. National Institutes of Health website.Available at: http://ods.od.nih.gov/factsheets/vitamind.asp . Accessed May 3, 2009.
Facts about Dietary Supplements. National Institutes of Health website. Available at: http://www.nih.gov/ .
Food and Nutrition Information Center. US Department of Agriculture website. Available at: http://www.usda.gov/wps/portal/usdahome .
Garrison RH, Somer E. The Nutrition Desk Reference. Keats Publishing; 1995.
Giovannoni G, Ebers G. Multiple sclerosis: the environment and causation. Curr Opin Neurol. 2007;20:261-268.
Ginde AA, Mansbach JM, Camargo CA. Association between serum 25-hydroxyvitamin D level and upper respiratory tract infection in the Third National Health and Nutrition Examination Survey. Arch Intern Med. 2009;169:384-390.
Heath KM, Elovic EP. Vitamin D deficiency: implications in the rehabilitation setting [review]. Am J Phys Med Rehabil. 2006;85:916-923.
Michels KB, Mohllajee AP, Roset-Bahmanyar E, Beehler GP, Moysich KB. Diet and breast cancer: a review of the prospective observational studies. Cancer. 2007;109(Suppl 12):2712-2749.
Munger KL, Levin LI, Hollis BW, Howard NS, Ascherio A. Serum 25-hydroxyvitamin D levels and risk of multiple sclerosis. JAMA. 2006;296:2832-2838.
Wagner CL, Greer FR. Prevention of rickets and vitamin D deficiency in infants, children, and adolescents. Pediatric. 2008;1221142-1152.
Last reviewed April 2009 by ]]>Maria Adams, MS, MPH, RD]]>
Please be aware that this information is provided to supplement the care provided by your physician. It is neither intended nor implied to be a substitute for professional medical advice. CALL YOUR HEALTHCARE PROVIDER IMMEDIATELY IF YOU THINK YOU MAY HAVE A MEDICAL EMERGENCY. Always seek the advice of your physician or other qualified health provider prior to starting any new treatment or with any questions you may have regarding a medical condition.
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