raw kidney beans may help diabetics

Doug Skrecky (oberon@vcn.bc.ca)
Sun, 31 May 1998 04:30:28 -0700 (PDT)

Authors
Bardocz S. Grant G. Pusztai A.
Institution
Rowett Research Institute, Bucksburn, Aberdeen.
Title
The effect of phytohaemagglutinin at different dietary concentrations on the
growth, body composition and plasma insulin of the rat.
Source
British Journal of Nutrition. 76(4):613-26, 1996 Oct.
Abstract
Young growing rats weighing approximately 83 g were fed on diets containing
kidney bean (Phaseolus vulgaris) lectin (phytohaemagglutinin, PHA) in the
range of 0-0.45 g/kg body weight for 10 d to ascertain whether there was a
minimum dose below which the lectin had no significant effect on body and
skeletal muscle weights in comparison with pair-fed lectin-free controls.
Averaged over all experiments, PHA doses of less than 10 mg/d (0.12 g/kg body
weight) reduced body dry by 1.14 (SE 0.25) g when compared with controls.
Between 10 and 27 mg/d (0.12-0.32 g/kg body weight) a further reduction of
0.64 (SE 0.21) g occurred, suggesting a slight but steady decline of body dry
weight with increasing dose. However, above 27 mg/d the depression of growth
and changes in body composition accelerated. The difference between the
proportional losses of skeletal muscle and body weight was not significant at
doses of PHA below 10 mg/d (0.12 g/kg body weight) but the ratio of these
losses rose to 1.5-2.0 at doses above this. The proportional decrease in
lipid weight exceeded that of both body and skeletal muscle weights at all
lectin doses, suggesting that lipid catabolism was the first target of the
PHA effect. Plasma insulin level was depressed at the PHA dose of 0.02 g/kg
body weight at which growth depression and muscle atrophy were minimal but,
contrary to expectations, plasma glucose levels remained stable over the
whole PHA dose range. It appears that despite a PHA-induced lowering of blood
insulin, glucose catabolism is elevated by an unknown, possibly hormonal,
compensatory mechanism. Thus, because low insulin levels facilitate the
mobilization and catabolism of lipids, it may be possible to use low doses of
PHA to reduce hyperglycaemia and body fat.