Implications of antinutritional components in soybean foods.Liener IE.
Department of Biochemistry, College of Biological Sciences, University
of Minnesota, St. Paul 55108-1022.

There are a number of components present in soybeans that exert a
negative impact on the nutritional quality of the protein. Among those
factors that are destroyed by heat treatment are the protease
inhibitors and lectins. Protease inhibitors exert their
antinutritional effect by causing pancreatic hypertrophy/hyperplasia,
which ultimately results in an inhibition of growth. The lectin, by
virtue of its ability to bind to glycoprotein receptors on the
epithelial cells lining the intestinal mucosa, inhibits growth by
interfering with the absorption of nutrients. Of lesser significance
are the antinutritional effects produced by relatively heat stable
factors, such as goitrogens, tannins, phytoestrogens, flatus-producing
oligosaccharides, phytate, and saponins. Other diverse but ill-defined
factors appear to increase the requirements for vitamins A, B12, D,
and E. The processing of soybeans under severe alkaline conditions
leads to the formation of lysinoalanine, which has been shown to
damage the kidneys of rats. This is not generally true, however, for
edible soy protein that has been produced under milder alkaline
conditions. Also meriting consideration is the allergenic response
that may sometimes occur in humans, as well as calves and piglets, on
dietary exposure to soybeans.

PMID: 8142044