Many of us are aware that vitamin D is essential for bone health and strong teeth. Although there are many gaps in our understanding of other health effects of vitamin D, new research suggests that higher levels of the vitamin may also be important for helping to prevent chronic diseases and conditions including certain cancers, heart disease, diabetes and multiple sclerosis. Lately scientists have been finding that many of us may not be getting enough vitamin D, particularly if we live in latitudes like Canada, are older, spend most of our time indoors, use sunscreen regularly, have darker skin or have diets low in the vitamin.
We get our vitamin D from two sources: exposure to sunlight, which allows the body to produce its own vitamin D using ultraviolet light and cholesterol in the skin; and a limited number of food sources including fortified milk, fish, eggs and mushrooms. Mushrooms are the only vegetable that contain natural vitamin D. They contain a compound called ergosterol that is turned into vitamin D in the body.
Currently, the Adequate Intake (AI)* for vitamin D for adults to age 50 is 5 mcg per day (200 IU). It increases to 10 mcg (400 IU) per day for those 51-70 years and 15 mcg (600 IU) per day for those older than 70 years. Health Canada encourages everyone over the age of 50 to take a daily supplement of 400 IU of vitamin D. The Tolerable Upper Limit (UL) currently recommended by the Food and Nutrition Board, Institute of Medicine National Academies is 50 mcg (2000 IU) per day for adults. This includes both vitamin D from food sources and supplements.
A 1/2 cup serving (100g/3.5oz) of sliced fresh white mushrooms has 0.5 mcg (18 IU) of vitamin D, that is 9% of an adults Adequate Intake.
Fresh Mushrooms Can Help!
. A double-blind, randomized, placebo-controlled trial published in 2007 in the American Journal of Clinical Nutrition found that women who took a calcium supplement that contained 1100 IU vitamin D had a significantly lower incidence of cancer over 4 years compared to women taking a placebo.
. Another study found that colorectal cancer mortality was inversely related to higher blood levels of vitamin D.
. While this is great news, much more research is needed to confirm these results.
. Researchers in the U.K. found that dietary vitamin D supplementation was associated with a reduced risk of type 1 diabetes in children.
. Analysis of data from the Nurses' Health Study in the U.S. found that a combined daily intake of greater than 1200 mg calcium and greater than 800 IU vitamin D was associated with a 33% lower risk of type 2 diabetes compared to an intake of less than 600 mg calcium and 400 IU vitamin D.
. Results from the Iowa Women's Health Study showed an inverse relationship between both dietary and supplemental vitamin D and risk of rheumatoid arthritis.
. A study conducted at the Harvard School of Public Health in Boston found evidence that vitamin D intake may have a protective effect on risk of developing multiple sclerosis in women.
Mushrooms Make a Difference
. Add 1/2 cup sliced white button mushrooms to your green salad. Benefit: boost vitamin D by 18 IU (9% AI).
. Use 1/2 cup sliced shiitake mushrooms instead of sausage in pasta sauce or on pizza. Benefit: boost vitamin D by 96 IU (48% AI).
. Layer 3/4 cup sliced sautéed fresh white mushrooms onto grilled steak or chicken. Benefit: boost vitamin D by 17 IU (8% AI).
Grilled Mushroom, Cheese and Spinach Panini
For more mushroom nutrition information, great tips and delicious recipes visit www.mushrooms.ca.
* Adequate Intake (AI): established when evidence is insufficient to develop a Recommended Dietary Allowance (RDA) and is set at a level assumed to ensure nutritional adequacy.
- News Canada