We all need more sunshine, but in the meantime, take Vitamin D.
Rickets! That was only a problem when my grandmother was growing up. Not anymore. “We’re seeing evidence of Vitamin D deficiency in infants and children of all ages, as well as adolescents and adults,” says Carol Wagner, MD, FAAP, professor of pediatrics at Medical University of South Carolina. “We know more about vitamin D than we did even five years ago. Because of lifestyle changes and sunscreen usage, the majority of the population shows signs of deficiency as determined by measured vitamin D levels in blood.”
Vitamin D promotes calcium absorption from the intestinal system and helps to maintain adequate blood calcium and phosphorus levels, which are essential for bone mineralization and to prevent hypocalcemic tetany/muscle spasms. Vitamin D is essential for bone growth and bone remodeling. Vitamin D deficiency can lead to rickets, a bone softening disease most often noted in children under two years of age, and osteomalacia and osteoporosis in adults. Vitamin D also helps to modulate cell growth, neuromuscular and immune function, and reduction in inflammation, so Vitamin D may play a role in preventing some chronic diseases later in life, such as colon, prostate and breast cancer, type 2 diabetes, hypertension, glucose intolerance and multiple sclerosis.
The ideal level of Vitamin D is still a matter of opinion, but majority of researchers feel that most children and adults need supplements because of inadequate intake through diet and inadequate sun exposure.
How much vitamin D do I need to take?
Different organizations recommend different daily intakes. The following are some of the recommendations from some organizations in the United States.
|Daily recommendation||Academy of Pediatrics||Food and Nutrition Board||Vitamin D council||Endocrine board|
|Birth to 12 months||400 IU/day||400 IU/day||1000 IU/day||400-1000 IU/day|
|Children||400 IU/day||600 IU/day||1000 IU/25 lb body weight||600-1000 IU/day|
|Adults||600 IU/day >70 yrs – 800 IU/day||5000 IU/day||1500-2000 IU/day|
The Food and Nutrition Board recommended daily intakes are the official recommendations by the United States government.
Sunlight and vitamin D production:
Most people meet at least some of their vitamin D needs through direct sun exposure. Ultraviolet B radiation converts a precursor in uncovered skin to vitamin D3. The season, time of day, length of day, cloud cover/smog, length of exposure, amount of exposed skin, skin tone and sunscreens all affect the amount of UV radiation exposure and vitamin D production. It has been suggested by some vitamin D researchers that approximately 5-30 minutes of direct sun exposure between 10 am and 3 pm at least twice a week to face, arms, legs or back without sunscreen can lead to sufficient vitamin D synthesis. However, due to the association of UV radiation and the development skin cancer and skin damage, the Academy of Dermatology advises skin protection, including sunscreens and limiting sun exposure during the peak radiation time.
Very few foods naturally contain vitamin D. The flesh of fatty fish (such as salmon, tuna and mackerel) and fish liver oils are the best sources of the vitamin. Cod liver oil has 1,360 IU/tablespoon, swordfish contains 566 IU/3 oz serving and sockeye salmon has 447 IU/3 oz serving. In the 1930s, a milk fortification program was implemented in the United States to combat rickets, so almost all of the US milk supply is fortified with 100 IU/cup. Egg yolks and fortified cereals also provide a small amount of vitamin D.
Supplements for all:
The Academy of Pediatrics (AAP) recommends vitamin D supplements for infants, children and adolescents, especially breast feeding infants. Supplements can be via vitamin D alone or in multivitamin preparations.
- Nursing infants. The AAP recommends that exclusively and partially breast fed infants receive vitamin D supplements of 400 IU/day shortly after birth and to continue to receive these supplements until they are weaned and consume > 1 liter (32 oz)/day of vitamin D fortified formula or milk. Though breast feeding is the best source of nutrition for infants, the amount of vitamin D in breast milk varies significantly, even when nursing mothers take vitamin D supplements.
- All non-breast fed infants and older children who are drinking < 1 liter (32 oz)/day of vitamin D fortified formula or milk, should receive a vitamin D supplement of 400 IU/day.
- Adolescents who do not obtain 400 IU/day of vitamin D through vitamin D fortified milk (100 IU/8 oz serving) and vitamin D fortified foods (such as fortified juices, fortified cereals and egg yolks) should receive a vitamin D supplement of 400 IU/day.
- On the basis of available evidence, serum 25-OH vitamin D concentrations in the blood in infants and children should be equal or > 50 nmol/L
- Children with increased risk of vitamin D deficiency, such as those with increased skin pigmentation, decreased sunlight exposure, chronic diseases characterized by fat malabsorption (such as cystic fibrosis, etc) and those taking anti-seizure medication, may require higher doses of vitamin D supplementation
Information summarized from:
- Prevention of Rickets and Vitamin D deficiency in Infants, Children and Adolescents; Carol L. Wagner and Frank R Greer; Pediatrics, November 2008, volume 122, issue 5
- National Institutes of Health government health sheets- Vitamin D Fact Sheet for Professionals
- Vitamin D: On the Double; Committee on Nutrition 2007-2008; healthy children.org