Vitamin D and its nutrient partner, calcium, have long been recognized as crucial for bone health – a benefit of particular interest to women as the risk for bone fractures and osteoporosis is no joke as we age. The importance of adequate levels of vitamin D and calcium are indisputable, but in the last few years vitamin D has been a hot topic with theories about additional health benefits. A variety of studies investigated its impact on longevity, cancer, heart health and blood pressure with mixed results. The media latched onto these messages and vitamin D was heralded as a champion nutrient that Americans were lacking. To get the bottom of the D story, the Institute of Medicine (IOM) was commissioned by the U.S. and Canadian governments to take a deep dive into the data and provide us a consensus on the health effects and how much we need.(1) In late November of 2010, they published their findings and provided recommendations for intake. Here is their consensus on vitamin D.
The Benefits of Vitamin D
Make no bones about it — vitamin D is an essential nutrient that you need to maintain healthy bones. But what did the committee say about additional health benefits? After scouring the research and listening to scientific testimonies, the IOM concluded that the conclusion was inconclusive — a straight line could not be drawn between vitamin D and additional health benefits. However, the line was solid, in indelible ink, between vitamin D and bone growth and maintenance. We, especially women, definitely need adequate vitamin D for our bones.
How Much Vitamin D Is Adequate?
Based on their findings, the IOM created the following Dietary Reference Intakes for adults:
| Life Stage | Estimated Average Requirement (IU/day) | Recommended Dietary Allowance (IU/day) | Upper Tolerable Intake (IU/day) |
| 19-30 years | 400 | 600 | 4,000 |
| 31-50 years | 400 | 600 | 4,000 |
| 51-70 years males | 400 | 600 | 4,000 |
| 51-70 years females | 400 | 600 | 4,000 |
| >70 years | 400 | 800 | 4,000 |
| 19–50 years pregnant/lactating | 400 | 600 | 4,000 |
|
Where Do You Get Vitamin D?
There are three main ways to get enough vitamin D: dietary sources, safe sun exposure, and supplements.(2) Your health care provider can help you determine which mode of securing vitamin D is right for your lifestyle.
Eat Vitamin D
Food sources of naturally occurring vitamin D include fish, sun-dried mushrooms, and egg yolks.(2) There are also vitamin D-fortified foods available: cow's milk; non-dairy milks such as rice, soy, almond, and oat; orange juice; soft spreads; yogurt; and breakfast cereals.
Here are some foods that provide vitamin D:
Fish (the oily variety)
- 30–35 µg per 1 tbsp cod liver oil
- 8–13 µg per 3 oz pink salmon
- 5–9 µg per 3 oz sardines or mackerel
- 5 µg per 3 oz tuna, canned oil
Other natural sources
- 0.5 µg per 1 medium egg yolk
- 0.3 µg per 3 oz beef liver
- 0.4–63 µg per 100 grams of mushrooms
Fortified foods
- 2.5 µg per 1 cup cow's milk (actual content might vary)
- 2.5 µg per 1 cup orange juice
- 1.0 µg per 1 cup ready-to-eat cereal
How Much Sun?
As an active woman, if you're doing some of your exercise outside, you're likely achieving the 5–30 minutes of sun twice a week that is recommended to absorb enough vitamin D. Sun exposure should be on the face, arms, legs, or back, without sunscreen, during the peak hours of 10 a.m. to 3 p.m. However, because UV radiation from the sun contributes to skin cancer, the American Academy of Dermatology recommends getting the vitamin through food or supplement sources.(2)
Supplements?
Although food comes first, many people find it difficult to consume the vitamin D they need.(2) If you choose to supplement, consult your physician and remember that the current upper limit of vitamin D established by the Institute of Medicine is 4,000 IU for adults, so you should stay below that limit.(1,2)
References:
1. Consensus Report, Food and Nutrition Board, Institute of Medicine. Dietary Reference Intakes for Calcium and Vitamin D. November 30, 2010.
2. Dietary Supplement Fact Sheet: Vitamin D. Office of Dietary Supplements. Last accessed 4/30/10: http://ods.od.nih.gov/factsheets/vitamind.asp.
Topics:
Supplements, Research, Nutrition, Nutrition advice, Sports nutrition
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