One study found that anywhere from 40% to 100% of older adults in the U.S. have vitamin-D deficiency. More than half of postmenopausal women who take drugs for osteoporosis are deficient. This goes on and on: 52% of Hispanic and African-American adolescents; 48% of young girls in Maine; 42% of women under 50 by the end of winter; 97% of Canadians during some point in winter; and 32% of healthcare workers in a Boston hospital, even though they drank a glass of milk and took a multivitamin each day, and ate salmon at least once a week.
There are many causes of vitamin-D deficiency. Here are the most common, along with their contributing factors:
1. Reduced sun exposure:
— Living at higher than the 37th parallel during wintertime
— Having dark skin
— Using sunscreen for the first moments in sun
2. Reduced dietary intake:
— Eating less vitamin D-rich foods, such as fatty fish, fish liver oil
— Following a vegetarian and no-milk diet
3. Aging:
— Your skin and kidneys don’t make as much vitamin D anymore
— You don’t drink as much milk
— You are bound to a house or nursing home
4. Health conditions:
— Obesity: not outdoors as much and the vitamin D is bound to fat
— Liver disease: vitamin not well-absorbed in gut and liver not making as much
— Kidney disease: produce less active vitamin D and some lost in urine
— Hyperthyroidism: body doesn’t make as much
5. Medications
— Laxatives, “Olestra,” “Orlistat,” cholestyramine and colestipol reduce absorption
— Anticonvulsants, cimethidine, diuretics and lithium reduce vitamin D levels