USDA-ARS Dietary Fiber and Precision Nutrition Fellowship
*Applications are reviewed on a rolling-basis.
ARS Office/Lab and Location: A research opportunity is currently available with the U.S. Department of Agriculture (USDA), Agricultural Research Service (ARS), located in Beltsville, Maryland.
The Agricultural Research Service (ARS) is the U.S. Department of Agriculture's chief scientific in-house research agency with a mission to find solutions to agricultural problems that affect Americans every day from field to table. ARS will deliver cutting-edge, scientific tools and innovative solutions for American farmers, producers, industry, and communities to support the nourishment and well-being of all people; sustain our nation’s agroecosystems and natural resources; and ensure the economic competitiveness and excellence of our agriculture. The vision of the agency is to provide global leadership in agricultural discoveries through scientific excellence.
Research Project: This appointment is part of the Methods and Applications of Food Composition Laboratory effort improve the speed, accuracy, and/or sensitivity of methods for measuring nutrients in the foods Americans eat. Dietary fiber (DF) is the polymeric carbohydrate portion of plant-based foods not hydrolyzed by human digestive enzymes. DF consumption has been linked to reduced plasma cholesterol concentration, improved glucose regulation, and decreased incidence of heart disease and colorectal cancer. Since 2005 the Dietary Guidelines for Americans have listed underconsumption of DF as a public health concern, however changes the definition of DF have resulted in a complicated and costly process for measuring DF content in foods. The goal of this project is to reduce the cost of dietary fiber analysis. The development of a simplified method for DF determination and adoption by professional organizations such as the AOAC or Cereals & Grains (formerly AACC) would benefit
The fellow will learn how to generate an instrumental method for soluble dietary fiber analysis, along with exemplar data sufficient to initiate an interlaboratory study, which is required for AOAC and AACC approval. Samples of beans (Great Northern and black), cereal grains (whole wheat and rice), ancient grains (sorghum and spelt), pseudocereals (amaranth and buckwheat), and traditional foods with novel carbohydrate components such as algae (nori and kombu) will be commercially obtained. Lyophilized, ground, food samples will be digested and under the biomimetic conditions of AOAC 2022.01 in tared digestion tubes, however after digestion, IDF will be isolated by centrifugation. Bypassing precipitation, proteinaceous and mineral components will be removed from the supernatant using ion exchange resins. The supernatant will be lyophilized and reconstituted at several levels of dilution to optimize method selectivity and sensitivity. Each level will receive the internal standard, diethyleneglycol, and be analyzed by size exclusion chromatography followed by RI detection and universal mass calibration will be performed by viscometry. As a universal detector, RI allows for absolute quantitation of soluble dietary fiber with no need for ash or nitrogen correction, saving time and reducing cost. Universal mass calibration will offer true molecular weight data for soluble fiber composition. These data will be published in an AOAC or AACC journal, and a potential interlaboratory study.
Learning Objectives: As a result of this training, the participant will gain knowledge and experience in:
- Enzymatic, chromatographic and related methods for the analysis of dietary fiber and other carbohydrates.
- Analytical method validation, including assessment of analytical figures of merit, robustness, and method detection limits.
- Statistical methods used to evaluate assay variability in nutrition science.
Mentor(s): The mentor for this opportunity is Michael Bukowski (michael.bukowski@usda.gov). If you have questions about the nature of the research, please contact the mentor(s).
Anticipated Appointment Start Date: As soon as possible, or February 6, 2026. Start date is flexible and will depend on a variety of factors.
Appointment Length: The appointment will initially be for one year, but may be renewed upon recommendation of ARS and is contingent on the availability of funds.
Level of Participation: The appointment is full time.
Participant Stipend: The participant will receive a monthly stipend commensurate with educational level and experience. The anticipated stipend range is $7,500 - $8,000 monthly.
Citizenship Requirements: This opportunity is available to U.S. citizens only.
ORISE Information: This program, administered by ORAU through its contract with the U.S. Department of Energy (DOE) to manage the Oak Ridge Institute for Science and Education (ORISE), was established through an interagency agreement between DOE and ARS. Participants do not become employees of USDA, ARS, DOE or the program administrator, and there are no employment-related benefits. Proof of health insurance is required for participation in this program. Health insurance can be obtained through ORISE.
Questions: Please visit our Program Website. After reading, if you have additional questions about the application process, please email ORISE.ARS.HQPostdoc@orau.org and include the reference code for this opportunity.
Qualifications
The qualified candidate should have received a doctoral degree in one of the relevant fields. Degree must have been received within the past five years.
Stipend
$7,500.00 – $8,000.00 Monthly
Point of Contact
Eligibility Requirements
- Citizenship: U.S. Citizen Only
- Degree: Doctoral Degree.