National Nutritional Monitoring System Biomarkers Needed - FDA's Yetley

The National Nutritional Monitoring System should be improved to provide more data on biochemical indicators and biomarkers of nutritional status, CFSAN Office of Special Nutritionals Director Elizabeth Yetley, PhD, suggested Dec. 8.

Speaking at an Institute of Medicine symposium in Washington, D.C., the FDA Center for Food Safety & Applied Nutrition rep said such data "are the most robust, the most compelling and the most informative."

"In part, the lack of a larger number of [biomarkers] is [based on] the fact the science base isn't there and we don't necessarily have validated interpretable biomarkers. But also, to some degree, it's a lack of funding for" the nutritional monitoring surveys, Yetley said.

FDA uses data from the National Health & Nutrition Examination Survey (NHANES) and the Continuing Survey of Food Intake by Individuals (CSFII) in a variety of ways, including risk assessment and food safety evaluations.

Yetley suggested the monitoring systems be adapted to consider substances that are added to foods and supplements to produce a desired physiological effect, rather than merely a technical effect such as color, flavor and texture.

Because such ingredients are added for physiological effect, "this means that the intakes, the exposures are likely to be much larger than they were previously with more inert substances," Yetley said.

"It means that our ways of compensating for uncertainty in our intake estimates are more challenging....We need to start to look at additive effects - how does one substance being added for a physiological effect interact with another substance that has a similar physiological effect. We can't depend on just a single substance analysis," the CFSAN rep said.

More detailed food product descriptions and expert guidance on interpreting the data also would be useful, Yetley added.

Council for Responsible Nutrition VP-Scientific & Regulatory Affairs Annette Dickinson, PhD, said the NHANES and CSFII databases are used by the dietary supplement industry primarily for policy development.

NHANES, which matches biochemical and clinical data with information about diet and lifestyle, allows for correlation among supplement use and blood levels of nutrients as well as other health measures, such as dietary habits, lifestyle characteristics and disease outcomes.

Dickinson noted CFSII provides data on nutritional status and dietary supplement use based upon two days of recall and breaks out data by broad income category and participation in the federal food stamp program. CRN is an advocate of using food stamps to purchase dietary supplements (¹ (Also see "Vitamin/Mineral Supplement Food Stamp Purchases Focus Of USDA Report" - Pink Sheet, 6 Dec, 1999.)).

"There is, I believe, a minimal use of these national survey data among companies in the dietary supplement industry to actually formulate products," Dickinson said.

"I believe the reason for that is these products are formulated for selection by consumers who have essentially evaluated their own nutritional status or their own need...for certain other dietary supplement ingredients and are not formulated for the entire population in the same way that a food...might be," the CRN rep added.

Dickinson cited cohort and clinical data, as well as commercial resources such as Information Resources Inc., Gallup and The Hartman Group, as more useful to the dietary supplement industry in formulating products and monitoring market conditions. The Hartman Group is affiliated with F-D-C Reports' Dietary Supplement Market View.

Dickinson suggested the national nutrition monitoring data should take into account more days of nutrient intake and be made available in a more timely fashion.

Ruth Etzel, MD/PhD, of USDA's Food Safety & Inspection Service, suggested the national nutrition monitoring surveys provide an opportunity for identifying populations susceptible to foodborne illnesses related to vitamin and mineral deficiencies.

Etzel cited studies linking vitamin A and zinc deficiencies to higher rates of severe diarrhea in children. In addition, there is "compelling information that nutrition status could affect the ability of the virus or pathogen to be infective and virulent in the host," the Division of Epidemiology & Risk Assessment director said, citing evidence demonstrating certain viruses are virulent in animals deficient in selenium or vitamin E.