Friday, December 14, 2007
Winter months feature lack of sunlight – and Vitamin D
There is probably a reason why this time of year is loaded with holidays and activities. The days are shorter, it gets darker earlier and every one is just a little bit cranky. Looking forward to Thanksgiving, Christmas, Hanukkah, New Years and even Valentines Day gives us a reason to get up on a cold dark morning.
Because of the shorter periods of sunlight in New England and colder weather keeping some of us inside more, we are also producing less Vitamin D. Vitamin D is a fat soluble vitamin that is produced when our skin is exposed to ultraviolet light (sunshine). It is also found in fortified foods, such as milk, orange juice, soymilk and breakfast cereals. Fatty fish, egg yolk and mushrooms are also sources of the vitamin.
Vitamin D is most well known for promoting bone health by increasing the body’s ability to absorb calcium and phosphorous. It also helps to promote bone formation. Low amounts of Vitamin D in the diet increases risk of the bone disease, Osteoporosis. Prior to the 1930’s, rickets was a major public health problem for children, until milk began to be fortified with Vitamin D. Low blood levels of Vitamin D are also associated with high blood pressure, some types of cancer (skin and colon), depression and autoimmune diseases.
Recommended Daily Intake (RDI) for Vitamin D is 200 International Units (IU) for children and for men and women under 50 years of age. Recommendations go up for people over 50 to 400 IU daily and to 600 IU for those over age 70. Needs increase with aging because the skin makes less pre-vitamin D as it ages and the liver and kidney convert less pre-vitamin D to the active, useful form of the vitamin. An 8-ouce glass of fortified milk contains 100 IU of vitamin D, and 3 ½ ounces of cooked salmon provides 360 IUs. Mushrooms are an excellent source for vegans.
During the months of November through February, the New England sun is an insufficient source of Vitamin D. If outdoor exposure to sunlight is limited and getting away to southern climates is not an option, it becomes important to obtain Vitamin D through foods or supplements. Using sunscreen, which is recommended to prevent skin cancers, also limits ultraviolet light exposure, reducing the production of Vitamin D. During the spring and summer months adequate Vitamin D can be obtained by exposure to sunlight for 10-15 minutes daily.
As I write this column, the view out my window is dreary, with a few snow flurries. A little salmon for dinner and some mushrooms in the salad might be a good idea. Then I think I’ll book a little Island getaway. All for the sake of my bones, of course.
Mary Beth Dahlstrom Green is a dietitian at The William W. Backus Hospital. This column should not replace advice or instruction from your personal physician. E-mail Green and all of the Healthy Living columnists at healthyliving@wwbh.org
Because of the shorter periods of sunlight in New England and colder weather keeping some of us inside more, we are also producing less Vitamin D. Vitamin D is a fat soluble vitamin that is produced when our skin is exposed to ultraviolet light (sunshine). It is also found in fortified foods, such as milk, orange juice, soymilk and breakfast cereals. Fatty fish, egg yolk and mushrooms are also sources of the vitamin.
Vitamin D is most well known for promoting bone health by increasing the body’s ability to absorb calcium and phosphorous. It also helps to promote bone formation. Low amounts of Vitamin D in the diet increases risk of the bone disease, Osteoporosis. Prior to the 1930’s, rickets was a major public health problem for children, until milk began to be fortified with Vitamin D. Low blood levels of Vitamin D are also associated with high blood pressure, some types of cancer (skin and colon), depression and autoimmune diseases.
Recommended Daily Intake (RDI) for Vitamin D is 200 International Units (IU) for children and for men and women under 50 years of age. Recommendations go up for people over 50 to 400 IU daily and to 600 IU for those over age 70. Needs increase with aging because the skin makes less pre-vitamin D as it ages and the liver and kidney convert less pre-vitamin D to the active, useful form of the vitamin. An 8-ouce glass of fortified milk contains 100 IU of vitamin D, and 3 ½ ounces of cooked salmon provides 360 IUs. Mushrooms are an excellent source for vegans.
During the months of November through February, the New England sun is an insufficient source of Vitamin D. If outdoor exposure to sunlight is limited and getting away to southern climates is not an option, it becomes important to obtain Vitamin D through foods or supplements. Using sunscreen, which is recommended to prevent skin cancers, also limits ultraviolet light exposure, reducing the production of Vitamin D. During the spring and summer months adequate Vitamin D can be obtained by exposure to sunlight for 10-15 minutes daily.
As I write this column, the view out my window is dreary, with a few snow flurries. A little salmon for dinner and some mushrooms in the salad might be a good idea. Then I think I’ll book a little Island getaway. All for the sake of my bones, of course.
Mary Beth Dahlstrom Green is a dietitian at The William W. Backus Hospital. This column should not replace advice or instruction from your personal physician. E-mail Green and all of the Healthy Living columnists at healthyliving@wwbh.org
# posted by ----------------- @ 9:35 PM 
