ATLANTA — Data published by the Centers for Disease Control and Prevention shows that overall the U.S. population has good levels of vitamin A, vitamin D and folate, but specific population groups such as black Americans and women of childbearing age face insufficiency issues for nutrients such as vitamin D and iodine. The information was published in the agency’s “Second national report on biochemical indicators of diet and nutrition” and covers the years 1999 to 2006 with an emphasis on 2003 to 2006, the newest data available.
“These findings are a snapshot of our nation’s overall nutrition status,” said Christopher Portier, Ph.D., director of the C.D.C.’s National Center for Environmental Health. “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.”
The report also found that deficiency rates for vitamins and nutrients vary by age, gender, or race/ethnicity and may be as high as 31% for vitamin D deficiency in non-Hispanic blacks.
“Research shows that good nutrition can help lower people’s risk for many chronic diseases,” said Christine Pfeiffer, Ph.D., lead researcher, in the Division of Laboratory Sciences in the C.D.C.’s National Center for Environmental Health. “For most nutrients, the low deficiency rates, less than 1% to 10%, are encouraging, but higher deficiency rates in certain age and race/ethnic groups are a concern and need additional attention.”
The C.D.C. called folic acid fortification of foodstuffs a “sustained public health success.” The report found that the fortification of cereal-grain products with folic acid, which began in 1998, has had a sustained positive impact on blood folate levels. The report showed folate deficiency dropped to less than 1% after fortification. The report also showed that blood folate levels in all race/ethnic groups are 50% higher since fortification began.
Before fortification began, approximately 12% of women of childbearing age were deficient in folate, as determined by blood folate levels. Folate is essential during periods when cells rapidly divide and grow, which is particularly important for women prior to and during pregnancy and for children during infancy.
The higher rate of vitamin D deficiency in non-Hispanic blacks presents a confusing situation for the C.D.C., because clinical data has shown greater bone density and fewer fractures in this population group. The agency said further research is needed to explain why the population group has better bone health but a higher rate of vitamin D deficiency.
The report’s findings were not as encouraging with regard to the iodine status in young women in the age group 20 to 39. The group had iodine levels that were just above iodine insufficiency. The young women also had the lowest iodine levels among any age group of women. Iodine is an essential component of thyroid hormones that regulate human growth and development.
First-time data on blood levels of fatty acids in the U.S. population was also a part of the C.D.C. study. The data include heart healthy polyunsaturated fatty acids as well as saturated fatty acids that increase risk of heart disease. The report found heart healthy polyunsaturated fatty acid levels in plasma differ by race/ethnicity. The first time measurements provide a baseline that will allow the C.D.C to track fatty acid levels over time, which will evaluate the nation’s progress toward heart healthy diets, according to the agency.
For more information regarding the “Second national report on biochemical indicators of diet and nutrition,” visit www.cdc.gov/nutritionreport/.