Nutrient retention

Nutrient retention describes how much of a particular nutrient remains in food after cooking or another preparation step, relative to the amount present beforehand. It is specific to both the nutrient and the preparation process. Retention factors are used in food composition calculations to estimate cooked-food nutrient amounts when direct measurements are unavailable .¹

True retention compares the total amount of a nutrient in the cooked food with its total amount in the original raw food, usually as a percentage. Calculating it requires the food's weight and nutrient concentration before and after cooking. Comparing concentration alone can be misleading because cooking changes food weight: water loss can concentrate a nutrient, while water absorption can dilute it, without a corresponding change in its total amount .^1,2

An alternative called apparent retention compares nutrient concentrations on a dry-weight basis. Removing water from the calculation helps address moisture changes, but it does not account for solids lost during cooking. A nutrient missing from the retained food may have moved into discarded liquid rather than been destroyed. Measuring the discarded material is needed to distinguish these possibilities and account for where the original nutrient went .²