Adhering to a
galactose-free diet by strictly avoiding dairy products and known hidden sources of galac-tose does not completely normalize
galactose-1-phosphate (gal-1-P) in erythrocytes from patients with
galactosemia. Major neurological complications, even in the best treated patients, are threatening a good clinical outcome and dictate a continuous search for leaks in the dietary regimen.
Raffinose and
stachyose, present in important amounts in various vegetables, contain alpha-1,4 linked
galactose which is cleaved only by bacterial
alpha-galactosidases, presumably in the lower part of the gut. In order to test the hypothesis whether
galactose released from
raffinose and
stachyose could be a source of absorbed
galactose and a cause of elevated gal-1-P six patients with
galactosemia (aged 6-24 years), underwent a
raffinose- and
stachyose-poor dietary regimen for 2 weeks. Before, after, and during the test period, the daily intake of
stachyose and
raffinose as well of
protein,
carbohydrate, fat and minerals was calculated from food protocols obtained from the patients. Plasma
galactose and erythrocyte gal-1-P were measured at the end of the three test phases.
Stachyose and
raffinose intake was reduced to 5%-10% during the experimental diet, which was well tolerated, except for
constipation in some patients. In five of the six patients gal-1-P in erythrocytes was somewhat lower (statistically not significant) during the test phase than during regular diet while plasma
galactose remained unchanged.
Galactose released from
raffinose and
stachyose may be absorbed and contribute to elevated gal-1-P values in erythrocytes of galactosemic patients.