While it is well known that vitamin D plays a crucial role in proper mineralization of bone (and preventing rickets in children and osteoporosis in adults), its importance in promoting healthy immune function has only recently been appreciated. Now a recent article in Pediatrics demonstrates:
Vitamin D supplementation significantly reduced the risk of ARIs in winter among Mongolian children with vitamin D deficiency.
It’s impressive that supplementing with only half the daily recommended amount of vitamin D (300IU) resulted in a 50% reduction in the incidence of acute respiratory infections (ARIs).
Recommended dietary allowances (RDA’s) of vitamin D are available online from the NIH:
Recommended Dietary Allowances (RDAs) for Vitamin D [1] Age Male Female Pregnancy Lactation 0–12 months* 400 IU
(10 mcg)400 IU
(10 mcg)1–13 years 600 IU
(15 mcg)600 IU
(15 mcg)14–18 years 600 IU
(15 mcg)600 IU
(15 mcg)600 IU
(15 mcg)600 IU
(15 mcg)19–50 years 600 IU
(15 mcg)600 IU
(15 mcg)600 IU
(15 mcg)600 IU
(15 mcg)51–70 years 600 IU
(15 mcg)600 IU
(15 mcg)>70 years 800 IU
(20 mcg)800 IU
(20 mcg)* Adequate Intake (AI)
This fact sheet from the NIH about vitamin D is excellent and worthy of review. It is important to note that if you are not drinking at least 4 cups (32 ounces) a day of vitamin D-fortified milk, you may not be getting enough vitamin D. There is an excellent table showing that there are very few natural food sources that provide sufficient vitamin D:
Selected Food Sources of Vitamin D [11] Food IUs per serving* Percent DV** Cod liver oil, 1 tablespoon 1,360 340 Swordfish, cooked, 3 ounces 566 142 Salmon (sockeye), cooked, 3 ounces 447 112 Tuna fish, canned in water, drained, 3 ounces 154 39 Orange juice fortified with vitamin D, 1 cup (check product labels, as amount of added vitamin D varies) 137 34 Milk, nonfat, reduced fat, and whole, vitamin D-fortified, 1 cup 115-124 29-31 Yogurt, fortified with 20% of the DV for vitamin D, 6 ounces (more heavily fortified yogurts provide more of the DV) 80 20 Margarine, fortified, 1 tablespoon 60 15 Sardines, canned in oil, drained, 2 sardines 46 12 Liver, beef, cooked, 3 ounces 42 11 Egg, 1 large (vitamin D is found in yolk) 41 10 Ready-to-eat cereal, fortified with 10% of the DV for vitamin D, 0.75-1 cup (more heavily fortified cereals might provide more of the DV) 40 10 Cheese, Swiss, 1 ounce 6 2 * IUs = International Units.
** DV = Daily Value. DVs were developed by the U.S. Food and Drug Administration to help consumers compare the nutrient contents among products within the context of a total daily diet. The DV for vitamin D is currently set at 400 IU for adults and children age 4 and older. Food labels, however, are not required to list vitamin D content unless a food has been fortified with this nutrient. Foods providing 20% or more of the DV are considered to be high sources of a nutrient, but foods providing lower percentages of the DV also contribute to a healthful diet.