Nutrient levels in the US population are generally good, but deficiencies among certain population groups are a cause for concern, says a new report from the Centers for Disease Control and Prevention.
The CDC’s Second National Report on Biochemical Indicators of Diet and Nutrition shows that, in general, the nation has an adequate nutritional status, but vitamin D, iron and iodine deficiencies in select population groups need ‘additional attention’.
Results of the survey showed that vitamin D deficiency, for example, can affect as many as 31% of non-Hispanic blacks.
In addition, women of childbearing age have iodine levels border on insufficiency, said the report. This is a concerning finding since iodine plays a key role in fetal brain development during pregnancy.
“Research shows that good nutrition can help lower people's risk for many chronic diseases,” said Christine Pfeiffer, PhD, lead researcher, in the Division of Laboratory Sciences in CDC's National Center for Environmental Health.
“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.”
The CDC analyzed 58 biochemical indicators in blood and urine samples collected from participants in CDC's National Health and Nutrition Examination Survey between 1999 and 2006.
Since the introduction of mandatory folic acid fortification of grain products, the level of folate deficiency has dropped significantly. The CDC report showed that deficiency for the B vitamin is now less than 1%. Before fortification began, about 12% of women of childbearing age were deficient in folate.
The report also indicated that vitamin D deficiency is higher in black Americans, with as much as 31% of the non-Hispanic black population being deficient.
Vitamin D deficiency in adults is reported to precipitate or exacerbate osteopenia, osteoporosis, muscle weakness, fractures, common cancers, autoimmune diseases, infectious diseases and cardiovascular diseases. There is also some evidence that the vitamin may reduce the incidence of several types of cancer and type-1 and -2 diabetes.
However, clinical data shows that non-Hispanic blacks have greater bone density and fewer fractures in this group, and the CDC report authors said that further research is needed to explain why non-Hispanic blacks have better bone health but yet have a higher rate of vitamin D deficiency.
Iodine and iron
While women of child bearing age, and their infants, are benefiting from the improvements in folate/folic acid levels, findings were not as encouraging with regard to the iodine status in young women (20-39 years of age).
The CDC report indicated that this age group had iodine levels that were just above iodine insufficiency
“Iodine is an essential component of thyroid hormones that regulate human growth and development. Iodine deficiency disorders include mental retardation, hypothyroidism, goiter, cretinism, and varying degrees of other growth and developmental abnormalities.
“Iodine is especially important in women during childbearing years to ensure the best possible brain development of the fetus during pregnancy,” explained the CDC.
The researchers also used a new marker of iron status, which showed high levels of iron deficiency in Mexican-American children aged 1 to 5 years (11%), and non-Hispanic black (16%) and Mexican-American women (13%) of childbearing age (12 to 49 years), compared with other race/ethnic groups.
Source: National Report on Biochemical Indicators of Diet and Nutrition in the U.S. Population 2012
Centers for Disease Control and Prevention (CDC)