Table 3.
Recommended nutrient intakes for dietary zinc (mg day−1) in pregnancy to meet the normative storage requirements from diets differing in zinc bioavailability and principal dietary characteristics for categorizing diets according to the potential bioavailability of their zinc † (adapted from WHO/FAO 2004)
| Trimester | High bioavailability | Moderate bioavailability | Low bioavailability |
|---|---|---|---|
| Refined diets low in cereal fibre and phytic acid content, with phytate–zinc molar ratio <5; adequate protein content principally from non‐vegetable sources, such as meats and fish. | Mixed diets containing animal‐fish protein. Lacto‐ovo, ovo‐vegetarian, or vegan diets not based primarily on unrefined cereal grains or high‐extraction‐rate flours. Phytate–zinc molar ratio of total diet = 5–15, or not >10 if more than 50% of the energy intake is accounted for by unfermented, unrefined cereal grains and flours and the diet is fortified with inorganic calcium salts. Availability of zinc improves when the diet includes animal protein or milks, or other protein sources or milks. | Diets high in unrefined, unfermented and ungerminated cereal grain, especially when fortified with inorganic calcium salts and intake of animal protein is negligible. Phytate–zinc molar ratio of total diet >15. High‐phytate, soya–protein products as the primary protein source. Diets in which approximately 50% of the energy intake is accounted for by the following high‐phytate foods: high‐extraction‐rate (≥90%) wheat, rice, maize, grains and flours, oatmeal and millet; chapatti flours and tanok; sorghum, cowpeas, pigeon peas, grams, kidney beans, black‐eyed beans and groundnut flours. High intakes of inorganic calcium salts, either as supplements or as adventitious contaminants, potentiate the inhibitory effects, and low intakes of animal protein exacerbate these effects. | |
| First | 3.4 | 5.5 | 11.0 |
| Second | 4.2 | 7.0 | 14.0 |
| Third | 6.0 | 10.0 | 20.0 |
†
At intakes adequate to meet the average normative requirements for absorbed zinc, the three availability levels correspond to 50%, 30% and 15% absorption.