Nutrition Report on Biochemical Indicators of Diet and Nutrition in the US Population

A report published by the CDC on April 2012 is based on 58 biochemical indicators of diet and nutrition measured by the CDC, together with NHANES data collected from 1999 until 2006. The concentration of vitamins, fatty acids, trace elements, metabolites, isoflavones, lignans, and acrylamide hemoglobin adducts were measured in blood or urine of demographic subgroups. [1]

Interesting outcomes were that fortification of grain-based food products with folic acid (vitamin B9) reduced the chances for neural tube birth defects. Age, ethnicity, and sex influence vitamin D deficiency, polyunsaturated fatty acids and  iron status.

Vitaminn D deficiency: Serum 25-hydroxyvitamin D deficiency (<30 nmol/L) were present  in 31% of the non-Hispanic blacks compared with 12% of Mexican Americans and 3% of non-Hispanic whites.

The CDC summarises its findings as follows:

• The rate of nutrient deficiencies in the general U.S. population ranges from less than 1% for folate, vitamin A, and vitamin E to about 10% for vitamin B6, vitamin D, and iron. For most nutrition indicators, deficiency rates vary by age, gender, or race/ethnicity, and can be as high as 31% for vitamin D deficiency in non-Hispanic blacks.
• Folate deficiency decreased to less than 1% after foods began being fortified with folic acid in 1998. Before fortification began, folate deficiency, as determined by blood folate levels, was approximately 12% for women of childbearing age. The report also shows that blood folate levels in all race/ethnic groups were 50% higher since fortification.
• Young women (20 to 39 years of age) had iodine levels close to levels indicating iodine insufficiency. This age group also had the lowest levels among any age group of women.
• Using a new marker of iron status, the report indicates higher rates of iron deficiency in Mexican-American children aged 1 to 5 years (11%) and in non-Hispanic black (16%) and Mexican-American women (13%) of childbearing age (12 to 49 years) when compared to other race/ethnic groups. The new iron marker measurements will help doctors better interpret iron status in individuals, especially in persons with disease that includes inflammation.
• The report offers first-time data on blood levels of fatty acids in the U.S. population. These include heart-healthy polyunsaturated fatty acids as well as saturated fatty acids that increase risk for heart disease. These first measurements in the U.S. population provide a baseline to track fatty acid levels over time. This will evaluate our nation’s progress toward heart-healthy diets.

Data from the NHANES survey:

• B vitamins (water-soluble vitamins category): People aged 40 years or older exhibit a higher likelihood of deficiency in vitamin B6 or vitamin B12 compared with younger individuals.
• Fatty acids (fat-soluble vitamins and nutrients category): Low (<100 μmol/L) concentrations of saturated, monounsaturated, and polyunsaturated fatty acids were more likely to be found in younger adults. Heart-healthy polyunsaturated fatty acids such as eicosapentaenoic acid or docosahexaenoic acid were found at higher concentrations in non-Hispanic black adults than in other ethnic groups. The survey included first-time measurements for 24 plasma fatty acids.
• Iron (trace elements category): According to the assessment of a new marker for iron status, the study reports iron deficiencies in 10.9% of Mexican-American children aged 1 to 5 years, 16.0% of non-Hispanic blacks, and 13.2% of Mexican-American women aged 12 to 49 years. Adult males, however, showed a higher risk for iron excess.
• Iodine (trace elements category): Lower urinary iodine concentrations, which can elevate the risk for disorders such as mental retardation or hypothyroidism, were observed more often in women aged 20 to 39 years than in other groups. Children generally exhibited higher iodine concentrations. Overall iodine concentrations, however, were reported to be relatively stable since the late 1980s.

[1] Second National Report on Biochemical Indicators of Diet and Nutrition in the US Population 2012
http://www.cdc.gov/nutritionreport/