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.
More information
The American Academy of Family Physicians has more about
vitamins and minerals.