I wonder if the enhanced learning that the researchers observed might have resulted not from the supplemental zinc per se, but from the zinc’s blocking absorption of fluoride in the juice. Most juice, especially grape and citrus, has enormous concentrations of fluoride from the pesticides used to produce it. Fluoride is known to cross the blood-brain barrier and to interfere with learning.
Jerry Malone Pueblo, Colo.
From the Nature Index
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