Effects of dietary galactose and fructose on rats fed diets marginal or adequate in copper for 9-21 months

This study was designed to monitor the metabolic differences after feeding starch, galactose and fructose diets with adequate or marginal copper levels to normal male rats over a period of 9-21 months. Two hundred and forty-five weanling male Sprague-Dawley rats weighing approximately 50 -60 g were randomly divided into one of the eight dietary groups. All diets were either Cu marginal (1.5 mug/g diet) or adequate (5-6 mug/g) with 627 carbohydrate (g/kg diet) as starch; 500 galactose and 127 starch; 500 fructose and 127 starch; or 400 galactose and 227 fructose. Glycated hemoglobin, ceruloplasmin oxidase activity, hematocrit, and plasma glucose, cholesterol, and triglyceride were measured in 72 rats after nine months. Galactose-fed rats had the lowest (P < 0.0001) body weights. Severe mortality rates were found in galactose-fructose-marginal Cu-fed rats. Marginal Cu deficiency significantly (P < 0.0001) reduced hepatic copper and increased hepatic Fe in all carbohydrate groups. Ceruloplasmin activity of the rats fed the marginal Cu and fructose-containing diets declined to undetectable levels and plasma cholesterol levels increased. Glycated hemoglobin was significantly (P 0.001) increased in the galactose-fed rats compared to fructose or starch-fed rats regardless of dietary copper concentration. The data suggest that dietary galactose and fructose exacerbate effects of long term marginal Cu intake including hypertrophy of liver, heart and kidney, hyperlipidemia, and increased mortality. (C) 2001 Elsevier Science Inc. All rights reserved.