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Dietary Modification

Dietary modifications are changes made during food preparation, processing, and consumption to increase the bioavailability of micronutrients—and reduce micronutrient deficiencies—in food at the commercial or individual/household level (Beck and Heath 2013). One example of dietary modification is the simultaneous consumption of iron-rich foods with ascorbic acid (vitamin C) (Gibson 2014), which increases the amount of iron absorbed by the body. Decreasing the amount of coffee and tea consumed with meals containing iron-rich foods is another example of dietary modification, because coffee and tea inhibit iron absorption.

Other strategies to increase bioavailability include (1) using germinated cereal flours containing amylase to increase the energy and nutrient density of cereal-based porridges; and (2) using processes like germination, fermentation, and soaking to reduce the phytate content, which can interfere with iron and zinc absorption. These practices improve the intake and absorption of micronutrients, thus reducing anemia.

Measurement and data sources

Data on the commercial or individual/household-level dietary modification are not easily available. Currently, tools or indices to assess dietary modification practices are not developed. Still, the consumption of specific foods that enhance or inhibit the absorption of micronutrients can be measured. Population-based surveys that measure household, or individual-level food consumption, may list specific foods and processing practices that enhance or inhibit the absorption of micronutrients. National Micronutrient Surveys, the Optifood tool (FANTA 2016), and other population-based surveys with dietary intake modules, collect information about coffee and tea consumption, which can decrease iron absorption when consumed with meals containing iron-rich foods. Other dietary modification practices—using germinated cereal flours in cereal-based porridges or germination, fermentation, and soaking practices in cooking to reduce the phytate content—may be available from individual research studies (Hotz and Gibson 2001; Hotz, Gibson, and Temple 2001; Hotz and Gibson 2005). It’s important to note that these dietary modification practices may vary by geographic location within a country, or by cultural or ethnic groups.

Methodological issues

  • Dietary modification practices, including processing and cooking methods, may vary significantly within a country. This makes findings difficult to generalize to national populations.


Beck, Kathryn L., and Anne-Louise M. Heath. 2013. “Dietary Approaches to Assessing Iron-Related Nutrition.” Current Opinion in Clinical Nutrition and Metabolic Care 16 (6): 712–18. doi:10.1097/MCO.0b013e328364f382.

FANTA. 2016. “Meeting Report: Evidence and Programmatic Considerations for the Use of Small-Quantity Lipid-Based Nutrient Supplements for the Prevention of Malnutrition.” Washington, DC: FHI 360/FANTA.

Gibson, Rosalind. 2014. “Enhancing The Performance Of Food-Based Strategies To Improve Micronutrient Status And Associated Health Outcomes In Young Children From Poor Resource Households In Low-Income Countries: Challenges And Solutions.” In Improving Diets and Nutrition: Food-Based Approaches, edited by Brian Thompson and Leslie Amoroso. Wallingford, Oxfordshire: CAB International; Rome, Italy: Food and Agriculture Organization of the United Nations.

Hotz, C., and R. Gibson. 2001. “Assessment of Home-Based Processing Methods to Reduce the Phytate Content and Phytate/zinc Molar Ratio of White Maize (Zea Mays).” Journal of Agricultural and Food Chemistry 49 (2): 692–98.

———. 2005. “Participatory Nutrition Education and Adoption of New Feeding Practices Are Associated with Improved Adequacy of Complementary Diets among Rural Malawian Children: A Pilot Study.” European Journal of Clinical Nutrition 59 (2): 226–37. doi:10.1038/sj.ejcn.1602063.

Hotz, C., R. Gibson, and L. Temple. 2001. “A Home-Based Method to Reduce Phytate Content and Increase Zinc Bioavailability in Maize-Based Complementary Diets.” International Journal of Food Sciences and Nutrition 52 (2): 133–42.