Two hundred sixty-six free-living human volunteers, 21-64 y old, were trained by dietitians to record daily their food intake for at least 7 d. Subsequently, they were fed diets of conventional foods adjusted in amounts to maintain their body weight for greater than or equal to 45 d. Comparing their estimated energy intake with the intake determined to maintain weight yielded mean differences of 2365 and 1792 kJ (565 and 428 kcal) in men and women, respectively, representing an underreporting of 18%. Twenty-two individuals (8%) overestimated and 29 (11%) were accurate to within 419 kJ (100 kcal) of their maintenance requirement. The remaining 215 individuals (81%) reported their habitual intake at 2930 +/- 1586 kJ (700 +/- 379 kcal) below that subsequently determined as their maintenance requirement. These findings suggest caution in the interpretation of food-consumption data.
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.
The effects on glucose tolerance of prolonged fructose feeding, at a level approximating that currently in the American diet, were examined in weaning, male Wistar rate. Two groups of rats were fed ad libitum diets containing either 54% cooked cornstarch (w/w) [CS] or 39% cooked cornstarch plus 15% D-fructose (CSF) for 3, 5, 7, 9 and 15 months. All rats were given an oral glucose tolerance test (250 mg glucose/100 g body weight) after each designated feeding period (hereafter referred to as age groups). Serum insulin and glucose were determined from blood obtained after fasting and 1/2 1, 2 and 3 hours following the glucose load. Neither body weight nor relative food intake (g/day/100 g body weight) differed significantly with diet. Fasting serum insulin increased linearly (r = 0.97) with age in both dietary groups, but was significantly higher (P less than 0.01) in CSF- than in CS-fed rats. Fasting serum glucose levels were also higher (P less than 0.05) in CSF-than in CS-fed rats. The levels decreased with age (r = 0.61) in CS-fed rats, but increased linearly with age (r = 0.96) in CSF-fed rats. Serum insulin response to the oral glucose load was higher (P less than 0.03) in all CSF-fed than in CS-fed rats. The serum glucose response curve following the oral load was significantly higher (P less than 0.025) in CSF-fed than in CS-fed rats at 7 months but not at other ages. Liver phosphoenolpyruvate carboxykinase (PEPCK, EC 4.1.1.32) activity, measured only in the 3-month group, was higher (P less than 0.05) in the CSF-fed rats, indicating higher gluconeogenic activity.
scite is a Brooklyn-based organization that helps researchers better discover and understand research articles through Smart Citations–citations that display the context of the citation and describe whether the article provides supporting or contrasting evidence. scite is used by students and researchers from around the world and is funded in part by the National Science Foundation and the National Institute on Drug Abuse of the National Institutes of Health.