Dietary reference intakes for zinc may require adjustment for phytate intake based upon model predictions

Area of Science:

• Nutritional Science
• Human Physiology
• Dietary Metabolism

Background:

• Zinc (Zn) absorption is primarily influenced by dietary zinc and phytate levels.
• Current Dietary Reference Intakes (DRI) for zinc were established using low-phytate diets.
• The impact of phytate on zinc requirements needs further quantification.

Purpose of the Study:

• To estimate the effect of increasing dietary phytate on zinc DRI.
• To model zinc absorption as a function of dietary zinc and phytate.
• To update the Estimated Average Requirement (EAR) and Recommended Daily Allowance (RDA) for zinc.

Main Methods:

• A trivariate model was employed to predict zinc absorption.
• The model incorporated updated parameters for dietary zinc and phytate.
• The model's predictions were compared against existing DRI values.

Main Results:

• The model's predicted EAR at zero phytate closely matched the Institute of Medicine's (IOM) EAR.
• Adding 1000 mg and 2000 mg of phytate doubled and tripled the EAR, respectively.
• The model indicated that EAR for men and women may not be met at phytate:Zn molar ratios exceeding 11:1 and 15:1.

Conclusions:

• Dietary phytate significantly increases zinc requirements.
• Current DRI may underestimate zinc needs in populations consuming high-phytate diets.
• Further experimental studies with higher zinc intakes are necessary to validate these findings.