MONDAY, April 2 (HealthDay News) -- Most Americans have good levels of vitamins A and D and folate -- a B vitamin -- but some groups of people need to increase their levels of vitamin D and iron, according to a federal report released Monday.
The study by the U.S. Centers for Disease Control and Prevention also found that rates of vitamin and nutrient deficiencies vary by age, gender and race/ethnicity, and can be as high as 31 percent for vitamin D deficiency among blacks.
The study results were based on measurements of vitamins and nutrients in blood and urine samples collected between 1999 and 2006 from participants in the CDC's National Health and Nutrition Examination Survey.
"These findings are a snapshot of our nation's overall nutrition status," Christopher Portier, director of CDC's National Center for Environmental Health, said in an agency news release. "Measurements of blood and urine levels of these nutrients are critical because they show us whether the sum of nutrient intakes from foods and vitamin supplements is too low, too high, or sufficient."
Lead researcher Christine Pfeiffer said in the release: "Research shows that good nutrition can help lower people's risk for many chronic diseases. For most nutrients, the low deficiency rates, less than 1 to 10 percent, are encouraging, but higher deficiency rates in certain age and race/ethnic groups are a concern and need additional attention."
Pfeiffer and her colleagues found that since the fortification of cereal-grain products with folic acid began in 1998, there has been a sustained increase in folate levels.
Folate deficiency has dropped to less than 1 percent, and blood folate levels in all racial/ethnic groups have increased 50 percent.
Folate is a B vitamin found in foods such as leafy green vegetables, fruits and dried beans and peas. Folic acid is a synthetic form of folate found in supplements and used to fortify foods, according to the U.S. National Institutes of Health.
Folate is especially important for women prior to and during pregnancy and for children during infancy. It can help prevent major birth defects of the brain and spine, such as spina bifida.
The CDC study found that rates of vitamin D deficiency were 31 percent among blacks, 12 percent among Mexican Americans and 3 percent among whites. Vitamin D is essential for good bone health and may also improve muscle strength and protect against cancer and type 2 diabetes, the researchers said.
Even though blacks had the highest rate of vitamin D deficiency, they had greater bone density and fewer fractures than the other groups. Further research is needed to explain these findings, the researchers said.
Among the other findings in the study:
- Women aged 20 to 39 had the lowest iodine levels among any age group of women and their levels were just above iodine insufficiency. Iodine is an essential component of thyroid hormones that regulate human growth and development.
- Compared to other racial or ethnic groups, iron deficiency was more common among Mexican American children aged 1 to 5 (11 percent), and among black and Mexican American women of childbearing age, 16 percent and 13 percent, respectively.
- Blood levels of heart-healthy polyunsaturated fatty acid differ by race/ethnicity.
The American Academy of Family Physicians has more about vitamins and minerals.
SOURCE: U.S. Centers for Disease Control and Prevention, news release, April 2, 2012
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