What Are The Causes Of Vitamin D Deficiency In Women?

Vitamin D is not a vitamin at all. It is actually a hormone manufactured by one part of the body to cause a response by other parts of the body. Vitamin D production begins in the skin and signals the gastrointestinal tract to absorb more calcium and phosphorus, the bones to release more, and the kidneys to retain more. In these ways, vitamin D helps maintain blood calcium concentration, supports bone formation and keeps bones from becoming brittle.

Deficiency

A deficiency of vitamin D can develop from causes related to lifestyle, diet, environment and certain disease states. A vitamin D deficiency creates a calcium deficiency because production of the protein that binds calcium slows down. Thus, a calcium deficiency develops even when adequate calcium comes from the diet. Women need 5 micrograms of vitamin D per day until age 50, 10 micrograms per day until age 70 and 15 micrograms per day after age 70.

Sunlight

Your body can make all the vitamin D it needs with the help of sunshine. Most of the world's population relies on sunlight to maintain adequate levels of vitamin D. In the U.S., people who live in regions of extreme northern latitude may have limited or no vitamin D production for as much as six months of the year. Factors that limit sun exposure include season of the year, time of day, air pollution, clothing, tall buildings, indoor living and sunscreens.

For most people, exposure of their hands, face and arms for 10 to 15 minutes on a clear summer day a few times a week enable sufficient vitamin D production from sunlight. The pigments of dark skin reduce vitamin D synthesis, so it may take up to 3 hours to produce the same amount of vitamin D as is produced in fair skin in 30 minutes.

Osteomalacia

Osteomalacia, the adult form of rickets, occurs in women who have low calcium intake and little exposure to the sun and who have had repeated pregnancies and periods of lactation. With this combination of risk factors, a woman's bones may soften and become bent. She may become bowlegged or have stooped posture.

Osteoporosis

When a woman fails to synthesize enough vitamin D or obtain it from foods or supplements, she may lose calcium from her bones and experience fractures. Working with calcium, vitamin D helps protect older adults from osteoporosis.

At-risk Populations

Vitamin D deficiency is most likely in older adults because your skin, liver and kidneys lose capacity to activate vitamin D as you age. Older adults often drink little or no milk, the main dietary source of vitamin D, and may spend much of their time indoors.

In addition to the elderly, persons at risk include those who are obese because subcutaneous fat sequesters vitamin D and alters its release into circulation. Persons who have had gastric bypass surgery may become vitamin D deficient over time because the site of its absorption is bypassed. Persons who have fat malabsorption diseases such as cystic fibrosis or an inflammatory bowel disease such as Crohn's are at risk because vitamin D is fat-soluble and requires fat for absorption.

Diet

Very few foods, mostly eggs, fish and fish-liver oils, naturally contain vitamin D but it is added to some foods, especially milk. People who are at risk of vitamin D deficiency can get an adequate supply by drinking 2 cups of vitamin D-fortified milk each day. Fortified margarine can help for those who use margarine rather than butter. A vegan diet does not meet the recommended intake of vitamin D without adequate sunshine, fortification or supplementation.