People who live in northern cities during winter at risk for vitamin D deficiency

February 18, 2015 in Nutrition Topics in the News, Vitamins, Minerals, Supplements

People who live in northern cities during winter at risk for vitamin D deficiency

Residents of snowy, northern U.S. cities are at risk of vitamin D deficiency and worse, may not even know it.

During Buffalo's winter months, nearly 50 percent of people have insufficient amounts of vitamin D and 25 percent may be considered deficient, say researchers at the University at Buffalo School of Public Health and Health Professions.

Those most at risk: the elderly, pregnant and nursing women, and people of color, whose skin acts as a natural sunscreen.

Unlike other vitamins, vitamin D is created by the body when the skin absorbs ultraviolet sunlight. But during winter months, people wear more clothes, are less likely to spend time outside and direct sunlight is hard to come by due to the Earth's tilt away from the sun. During the winter months in the northern U.S. and Canada, the sun’s rays are not strong enough to stimulate vitamin D synthesis in the skin.

Maintaining proper levels is crucial due to the vitamin's widespread effect on the body; every cell in the body is responsive to vitamin D. If you're deficient, you won't see the health effects for years and it could take months to get your levels back up, the researchers state.

Deficient levels of vitamin D may result in:

• Lower bone density

• Weakened immune system

• Increased risk for type 2 diabetes

• Higher susceptibility to some cancers

• Increased risk of death from cardiovascular disease

• Cognitive impairment in older adults

The elderly, whose skin produces lower amounts of the vitamin, often suffer difficulty with functional fitness, such as opening cans or standing up, when vitamin D levels are low.

Insufficiency is of particular concern in pregnant women and nursing mothers because it affects children at a time when their bones are developing and can result in rickets, the softening of bones.

For people who live in northern latitudes during the winter months are recommended to take 1,000 to 2,000 IU (international units) of vitamin D3 a day. The safe upper limit is 4,000 IU per day.

Vitamin D is found naturally in only a few foods, such as some fatty fish (mackerel, salmon, sardines), fish liver oils and eggs from hens that have been fed vitamin D. In the US and Canada, fluid milk is fortified with vitamin D so that they contain 100 IU per 1 cup (250 ml).

Source: The University at Buffalo

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