Zinc
The bioavailability of zinc from vegetarian
diets is lower than from nonvegetarian
diets, mainly due to the higher
phytic acid content of vegetarian diets
(31). Thus, zinc requirements for some
vegetarians whose diets consist mainly
of phytate-rich unrefined grains and legumes
may exceed the Recommended
Dietary Allowance (26). Zinc intakes of
vegetarians vary with some research
showing zinc intakes near recommendations
(32) and other research finding
zinc intakes of vegetarians significantly
below recommendations (29,33).
Overt zinc deficiency is not evident in
Western vegetarians. Due to the difficulty
in evaluating marginal zinc status,
it is not possible to determine the
possible effect of lower zinc absorption
from vegetarian diets (31). Zinc sources
include soy products, legumes, grains,
cheese, and nuts. Food preparation
techniques, such as soaking and
sprouting beans, grains, and seeds as
well as leavening bread, can reduce
binding of zinc by phytic acid and increase
zinc bioavailability (34). Organic
acids, such as citric acid, can also enhance
zinc absorption to some extent
(34).