GOOD SENSE eatingAsk any school-age child or his parents about vitamin D and you’ll get the standard reaction. The "Sunshine Vitamin." "Good for your bones." Both true, but during the last few years, there has been an explosion in knowledge about this mighty nutrient and its critical role in maintaining good health.
How D helps
In the body, vitamin D acts more like a hormone than a vitamin. After it’s made by the skin or ingested, the kidneys and liver help to convert it into an active hormone form. It then signals the intestine to absorb more phosphorus and calcium, helping to build strong bones. Young children deficient in calcium and vitamin D are unable to properly mineralize the skeleton, causing bowing of the legs (rickets).
Vitamin D also strengthens muscles, improves heart function and the immune system and helps regulate cell growth. Newer studies point to its role in the prevention of multiple sclerosis, 17 varieties of cancer, diabetes, obesity and rheumatoid arthritis.
Babette Zemel, Ph.D., director of the Nutrition and Growth Laboratory at Children’s Hospital of Philadelphia, found that 55 percent of children had inadequate levels of vitamin D. In the winter, 68 percent were deficient. Who was most likely to have low levels? African-American children, children above age 9 and those with low dietary vitamin D intake.
Diet during pregnancy counts, too. In a 2006 study, children whose mothers got plenty of vitamin D during pregnancy have bigger, strong bones at age 9. In fact, maternal vitamin D matters more than all the milk children drink in those first nine years.
It’s possible that vitamin D deficiency contributes to unexplained muscle pain. When University of Minnesota physician Gregory Plotnikoff, MD tested the vitamin D levels of 150 of his patients aged 10 to 65 with musculoskeletal pain of unknown origin, he found 93 percent to have low levels.
Sources of vitamin D
Vitamin D is one vitamin the human body can make on its own. It’s also a vitamin where food is not necessarily the best source. Vitamin D is naturally produced from cholesterol when the skin is exposed to the sun’s ultraviolet rays, but that’s a problem between November and February. And kids who are slathered in sunscreen don’t get enough sunshine during the summer.
In Zemel’s opinion, sensible sun exposure is the best way for children to get adequate vitamin D.
Since darker-skinned people synthesize vitamin D from the sun less efficiently (the extra pigment blocks more UV rays), those without good sunlight exposure should take special care to consume enough vitamin D-rich foods and supplements. Light-skinned people can get what they need in about 10 to 15 minutes of sunlight. One school of thought says to apply sunscreen after 15 minutes of sun exposure to optimize vitamin D production, while promoting cancer prevention.
Oily fish, such as salmon and mackerel, shiitake mushrooms and egg yolk are the only natural sources of vitamin D. Other foods, such as milk, juice and cereals, are fortified with it.
Supplements can fill the gap between dietary intake and what your child’s body needs. Children’s multivitamins typically contain 400 IU (800 to 1,000 IU are recommended daily for adults and kids). Zemel recommends that infants, especially those who are breastfed, receive supplements of 200 to 400 IU per day.
When selecting supplements, look for the animal-derived D3 (cholecalciferol) form of the vitamin. The plant-derived form, D2 (ergocalciferol) is less than one-third as potent as D3. Because vitamin D is fat soluble, have your child take it with a meal containing some fat to optimize absorption. Food sources of Vitamin DFood Amount Vitamin DHalibut, cooked 3 oz. 680Red salmon, canned ¼ cup 480Pink salmon, canned ¼ cup 290Salmon, cooked 3½ oz. 360Sardines, canned in oil 1¾ oz. 250Shrimp, cooked 3 oz. 170Mushrooms, shiitake, dried 4 249Milk, dairy 8 oz. 100 Milk, soy (fortified) 8 oz. 40-120Vitamin D-fortified OJ 8 oz. 100Dannon Frusion Smoothie 10 oz. 140|Yoplait Nouriche Smoothie 11 oz. 100Tuna, light, canned ¼ cup 130Yoplait Yogurt 6 oz. 80Margarine, fortified 1 Tbsp. 40-60Breakfast cereal, fortified ¾-1 cup 40Egg with yolk, large 1 20Multivitamin, typical 1 400• Vitamin quantities are in IU (International Units)
Source: U.S. Department of Agriculture
Ingredients2 whole wheat tortillas1/2 cup cooked salmon, flaked1/4 cup reduced-fat ranch dressing2 Tbsp grated carrots1/4 cup chopped spinach leaves
1. Mix salmon, carrots and dressing.
2. Divide between the tortillas, top with spinach, and roll tightly.
3. If you like, try these other wrap ideas: chicken, avocado and grated savoy cabbage; low-fat refried beans, cheese and tomato; hummus spread with finely grated red cabbage; or grated cheese and pasta sauce.
Yield: 2 wraps incorporating vitamin D-rich salmon
Nutrition information per wrap: 200 calories, 12 grams protein, 2 grams fiber, 8 g fat, 470 mg sodium, 97 IU vitamin D
Christine M. Palumbo, RD, is a registered dietitian in private practice in Naperville. She can be reached at (630) 369-8495 or www.ChristinePalumbo.com.
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