Twenty-four male subjects originally participated in a study to determine the effects of feeding diets comparatively low in copper (1.03 mg/day/2850 kcal) and containing either 20% fructose or starch on indices of copper status. During the course of feeding the diets for 11 wk, four of the subjects exhibited heart-related abnormalities and were removed from the study. Fructose ingestion had no effect on serum ceruloplasmin activity or serum copper concentration but did significantly reduce cuprozinc superoxide dismutase (SOD) activity of erythrocytes as compared to starch. Repletion of the subjects with 3 mg copper/day for 3 wk significantly increased SOD levels in subjects previously fed fructose but not starch. Apparent copper balance was significantly greater when the subjects consumed the fructose as compared to the starch diet. These results suggest that the type of dietary carbohydrate fed can differentially affect indices of copper status in humans.

Ten hyperinsulinemic and 11 nonhyperinsulinemic men consumed for 5 wk each in a cross-over design a diet, similar to one currently consumed in the United States, with 20% of the kilocalories from either fructose or high-amylose cornstarch to determine the effects of the two diets on various blood metabolites considered to be risk factors associated with heart disease. In the hyperinsulinemic men the intake of fructose as compared with cornstarch significantly increased total triglycerides and their lipoprotein distribution; total and very-low-density lipoprotein cholesterol; apoproteins B-100, C-II, C-III; and uric acid. In the nonhyperinsulinemic men total triglycerides, total and low-density lipoprotein cholesterol and uric acid were significantly greater after the consumption of fructose than after cornstarch. The results indicate that in a diet high in saturated fatty acids and cholesterol, fructose increases the levels of risk factors associated with heart disease, especially in hyperinsulinemic men.

Eleven men consumed a basal diet alone and with cellulose (Na-carboxymethylcellulose, locust bean gum, or karaya gum) added at 7.5 g fiber per 1000 calories for 4 wk each. Food, urine, and fecal composites were collected during the last 8 d of each feeding period. Bowel transit time was not significantly affected; however, total dry fecal weight was significantly increased after the refined fibers compared with that after the basal diet. Adding refined fibers to the basal diet did not significantly affect apparent mineral balance of calcium, magnesium, manganese, iron, copper, or zinc, with the exception of a negative mineral balance for manganese with carboxymethylcellulose. Karaya gum had a mean positive balance for all minerals tested. These results indicate that the hypocholesterolemic effect of the fibers that form gels occurs without compromising mineral balance in those subjects consuming Recommended Dietary Allowance levels of the minerals studied.

Experiments were conducted in copper deficient male and female rats fed diets containing fructose or starch in order to determine whether the same type of interaction between copper status and dietary carbohydrate found in male rats also occurs in the female rat. Mortality occurred only in the male rats fed the fructose diet deficient in copper with 40% of the animals dying during the 8 week study. Only anemia, hypercholesterolemia, increased BUN, heart hypertrophy and reduced body weight were observed in these animals which could be related to their mortality. Despite the increased mortality, plasma ceruloplasmin, erythrocyte SOD and hepatic copper concentrations were reduced to a similar extent in all rats regardless of the sex of the animals or of the type of dietary carbohdrate fed. The results of the present study indicate that although direct measurements of copper status of female rats fed fructose diet deficient in copper are similar to their male counterpart, they are apparently protected from the lethal consequences of the deficiency.

Ten hyperinsulinemic and 11 nonhyperinsulinemic men consumed a typical American diet containing 20% of calories either as fructose or as high-amylose cornstarch for 5 wk in a crossover design to determine their effects on indices of glucose tolerance. Blood glucose, insulin, and fructose were determined before and 30, 60, 90, 120 and 180 min after breakfast, lunch, and dinner. Glucose responses were significantly lower 60 and 120 min and the insulin response lower 60 min after the meals containing fructose. Hyperinsulinemic men showed a tendency toward decreased insulin sensitivity after consuming fructose on the basis of an increased insulin-to-glucose ratio and decreased insulin binding to erythrocytes. These results generally show a beneficial effect of fructose on glucose tolerance; however, recommendations for including large amounts of fructose in the diet should also be based on a complete evaluation of the effect on other metabolic risk factors.