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Biomedical subjects

F X Pi-Sunyer

Publications and source records attributed to F X Pi-Sunyer.

At least 109 records · Page 6Linked to original sources
PubMed1990

Frozen desserts and glycemic response in well-controlled NIDDM patients.

Fructose is known to elicit a lower glycemic response than sucrose, and high-fructose desserts have been recommended for a diabetic diet. We compared a cholesterol-free tofu-based frozen dessert (TFD) containing high-fructose corn syrups with a dairy-based sucrose-sweetened ice cream (IC). Six male and six female non-insulin-dependent diabetic patients (mean age 51 yr, mean ideal body weight 143%, fasting blood glucose less than 160 mg/dl) with well-controlled diabetes and managed on oral hypoglycemic agents were studied. Subjects underwent three trials. In the first trial they ingested 50 g glucose, and in the next two trials they ingested 50-g carbohydrate equivalents of either TFD or IC in random sequence. Venous blood was drawn at intervals during the 3-h trials for glucose and insulin determinations. Fasting plasma glucose was not statistically different between IC and TFD trials (130 vs. 121 mg/dl). Peak glucose responses were at 120 min in both trials (190 mg/dl for IC and 222 mg/dl for TFD), with those for TFD being significantly higher (P less than 0.01). Mean glucose area and glycemic index for TFD were significantly greater than for IC (P less than 0.01 and P less than 0.03, respectively). There was no significant difference between mean insulin areas. In summary, the TFD, which contains soybean curd and high-fructose corn syrup, might have been expected to produce more satisfactory postprandial blood glucose levels than IC, which contains sucrose, yet a higher glycemic response was elicited. This is related to the substantial amount of total glucose in this "fructose" dessert.(ABSTRACT TRUNCATED AT 250 WORDS)

Adult↗
PubMed1989

Exercise and obesity.

Exercise training in obese patients increases cardiorespiratory fitness, reduces cardiovascular disease risk factors, and increases caloric expenditure; however, significant exercise is required to induce changes in body composition in the absence of caloric restriction, particularly for people whose exercise capacity may initially be limited. Unless a large amount of lean tissue is lost by concomitant dietary restriction, it is unlikely that resting metabolism is altered by exercise, either long-term, or acutely after each workout. The thermic effect of food is negatively related to body fat content. Exercise prior to a meal improves the blunted thermic response to food in the obese but does not normalize it completely. It is noteworthy that physical activity is self-determined and is the only component of energy expenditure that is under volitional control. Exercise alone, without caloric restriction, is probably insufficient to yield significant fat loss except in individuals who are extremely motivated, whereas the combination of modest caloric restriction and physical training of different modes may be necessary to induce favorable changes in body composition.

Body Composition↗
PubMed1989

Absorption of inorganic, trivalent chromium from the vascularly perfused rat small intestine.

The absorption of inorganic, trivalent chromium (Cr) by the rat small intestine was investigated by quantifying three components of the absorptive process: 1) Cr uptake from a test meal, 2) Cr transport into the circulation and 3) Cr retention by the intestine. An in vitro, in situ double-perfusion technique was used in which the intestinal vasculature, from the superior mesenteric artery to the portal vein, and the intestinal lumen, from the duodenum to the ileum, were perfused simultaneously. The vasculature was perfused with a synthetic "plasma" (vascular perfusate) while the lumen was perfused with a nutrient-rich solution (intestinal perfusate) at concentrations of trivalent Cr of 0.2-20 mumol/l (10-1000 ppb). Dose-response curves, in which Cr transport, retention and uptake were plotted against the luminal Cr concentration, revealed that Cr absorption is a nonsaturable process. Regardless of the Cr concentration of the intestinal perfusate, 5.90 +/- 0.33% (mean +/- SEM) of the test dose was taken up from the meal, 5.52 +/- 0.33% was transported into the vascular perfusate and 0.38 +/- 0.03% was retained by the small intestine. Based on the criterion of saturability, it was concluded that inorganic, trivalent Cr is absorbed by the nonmediated process of passive diffusion in the small intestine of rats fed a Cr-adequate diet (1.44 micrograms Cr/g diet).

Absorption↗
PubMed1989

Impact of body fat mass and percent fat on metabolic rate and thermogenesis in men.

To clarify further the independent relationships of body composition parameters to energy expenditure, resting metabolic rate (RMR) and postprandial thermogenesis were studied in four groups who were matched for absolute fat mass (study 1) and relative fatness (study 2). In study 1, five lean [group A, 15.4 +/- 0.6% (+/- SE) body fat] and five obese men (group B, 25.0 +/- 0.9% fat) were matched on body fat mass (13.0 +/- 0.9 vs. 14.4 +/- 0.8 kg, respectively). Fat-free mass (FFM) and total weight were greater for group A than B. RMR was measured for 3 h in the fasted state and after a 720-kcal mixed meal. RMR was greater for group A than B (1.38 +/- 0.08 vs. 1.14 +/- 0.04 kcal/min, P less than 0.05). The thermic effect of food, calculated as 3 h postprandial minus fasting RMR, was greater for group A than B (65 +/- 6 vs. 23 +/- 9 kcal/3 h; P less than 0.05). In study 2, two groups (n = 6 men/group) were matched for percent body fat (33 +/- 1% fat for both) but differed in lean, fat, and total weights: 50.8 +/- 3.1 kg FFM for the lighter (group C) vs. 68.0 +/- 2.8 kg FFM for the heavier (group D) group, P less than 0.05. RMR was lower for group C than D (1.17 +/- 0.06 vs. 1.33 +/- 0.04 kcal/min, P less than 0.05), but the thermic effect of food was not significantly different (31 +/- 3 vs. 20 +/- 6 kcal/3 h).(ABSTRACT TRUNCATED AT 250 WORDS)

Adipose Tissue↗
PubMed1989

Dietary management of geriatric diabetes.

The most important dietary precept for elderly patients with diabetes mellitus is the maintenance of desirable body weight. Weight reduction is imperative for the obese. It is now proposed that the diet prescribed contain predominantly carbohydrate (50 to 60% of total calories) and that the carbohydrates be primarily complex and rich in fiber. Protein should be of high quality, but never in excess. A diet low in saturated fats and cholesterol and proportionately higher in polyunsaturated and monounsaturated fats seems prudent in view of the accelerated incidence of macrovascular disease in this population. Lipid profiles should be carefully monitored, and carbohydrate intake may need to be limited if hypertriglyceridemia is present. Vitamin and mineral supplements may be desirable. It is important to understand that the dietary guidelines for diabetic patients discussed in this article are not fundamentally different from those for any other person desiring a healthy diet. The nutritional program outlined is a good program for everyone, and the entire family is encouraged to participate in the meal planning and preparation involved.

Aged↗
PubMed1988

Effects of cholecystokinin-octapeptide (CCK-8) on food intake and gastric emptying in man.

Food intake and gastric emptying were measured simultaneously after cholecystokinin-octapeptide (CCK-8) and saline infusions in order to test the hypothesis that reduction in gastric emptying mediates the effect of CCK-8 on food intake. Each of twelve nonobese healthy men received intravenous infusions of CCK-8 and saline on separate nonconsecutive days after they had consumed 500 g of tomato soup tagged with technetium-99-DTPA. Intake of a test meal was measured 20 min after consumption of the soup while gastric emptying was simultaneously monitored by gamma emission scintigraphy of the soup. Food intake and gastric emptying of the soup were both significantly reduced by CCK-8 infusions in comparison to saline. There was a significant correlation between the amount of the test meal eaten and the amount of soup emptied during the period the test meal was being eaten, but not before the meal, only on days when CCK-8 was infused. Differences in intakes between days when saline was infused and days when CCK-8 was infused did not correlate with differences in gastric emptying of soup. These results suggest that CCK may amplify signals of satiety in proportion to the fullness of the stomach. Gastric emptying per se may not mediate the effects of CCK-8 on food intake.

Adult↗
PubMed1987

Sugar and sugar substitutes. Comparisons and indications.

Public confusion and concern about the use of sugar and sugar substitutes are widespread. Physicians must be prepared to answer patients' inquiries about these substances. Some population groups should avoid certain sugar substitutes. In particular, pregnant women and young children should avoid saccharin, and phenylketonuric homozygous persons should avoid aspartame. In a varied, balanced diet, the use of aspartame and saccharin is one safe way for the general population to enjoy sweet foods with fewer calories and less cariogenic potential. Sugar substitutes may be helpful in dietary compliance for overweight and diabetic patients.

Animals↗
PubMed1987

Exercise effects on calorie intake.

The promotion of exercise for the treatment of obesity has been based on the double premise that exercise generates special metabolic signals and that these reduce food intake. The decrease in intake coupled with the increase in expenditure leads to weight loss. Strong support for this premise comes primarily from animal studies, not from studies in humans. This arises in part because the premise is so difficult to prove in people. It ought to be a simple matter to exercise sedentary people and watch them eat less. In fact, the methodologic problems associated with measuring energy expenditure, voluntary changes in energy intake, and small shifts in body composition are great. As a result, there is a paucity of information in this area.

Animals↗
PubMed1987

Thermic effects of food and exercise in lean and obese men of similar lean body mass.

The thermic effect of food at rest, during 30 min of cycle exercise, and postexercise with two sequences of exercise and meal (before or after exercise) was compared in eight lean (mean +/- SE, 12.8 +/- 0.7% body fat) and eight obese men (29.7 +/- 0.6% fat) to determine whether exercise before or after a meal enhances thermogenesis. The groups were matched for age, height, and lean body mass (LBM) in order to study the relationship between thermogenesis and body fat independent of LBM. Metabolic rate was measured by indirect calorimetry on five mornings, in randomized order, after an overnight fast. Treatments on respective days were 1) 3-h rest, no meal; 2) 3-h rest after a 750-kcal mixed meal (14% protein, 31% fat, 55% carbohydrate); 3) during and 3 h after 30 min of cycling, no meal; 4) during and 3 h after 30 min of cycling, meal 30 min before exercise; and 5) 3 h after 30 min of cycling, meal immediately after exercise. The thermic effect of food, which is the fed minus fasted caloric expenditure, was significantly greater for the lean than the obese men under the resting (mean +/- SE 53 +/- 5 vs. 26 +/- 5 kcal over 3 h for the lean and obese groups, P less than 0.01), exercise (26 +/- 4 vs. 4 +/- 2 kcal over 30 min, P less than 0.01), and both postexercise conditions. However, for the lean men the thermic effect of food was significantly greater for the meal-before-exercise than the resting and the meal-after-exercise conditions.(ABSTRACT TRUNCATED AT 250 WORDS)

Adult↗
PubMed1987

Body composition, not body weight, is related to cardiovascular disease risk factors and sex hormone levels in men.

To clarify the independent relationships of obesity and overweight to cardiovascular disease risk factors and sex steroid levels, three age-matched groups of men were studied: (i) 8 normal weight men, less than 15% body fat, by hydrostatic weighing; (ii) 16 overweight, obese men, greater than 25% body fat and 135-160% of ideal body weight (IBW); and (iii) 8 overweight, lean men, 135-160% IBW, but less than 15% fat. Diastolic blood pressure was significantly greater for the obese (mean +/- SEM, 82 +/- 2 mmHg) than the normal (71 +/- 2) and overweight lean (72 +/- 2) groups, as were low density lipoprotein levels (131 +/- 9 vs. 98 + 11 and 98 + 14 mg/dl), the ratio of high density lipoprotein to total cholesterol (0.207 +/- 0.01 vs. 0.308 +/- 0.03 and 0.302 +/- 0.03), fasting plasma insulin (22 +/- 3 vs. 12 +/- 1 and 13 +/- 2 microU/ml), and the estradiol/testosterone ratio (0.076 +/- 0.01 vs. 0.042 +/- 0.02 and 0.052 +/- 0.02); P less than 0.05. Estradiol was 25% greater for the overweight lean group (40 +/- 5 pg/ml) than the obese (30 +/- 3 pg/ml) and normal groups (29 +/- 2 pg/ml), P = 0.08, whereas total testosterone was significantly lower in the obese (499 +/- 33 ng/dl) compared with the normal and overweight, lean groups (759 +/- 98 and 797 +/- 82 ng/dl). Estradiol was uncorrelated with risk factors and the estradiol/testosterone ratio appeared to be a function of the reduced testosterone levels in obesity, not independently correlated with lipid levels after adjustment for body fat content. Furthermore, no risk factors were significantly different between the normal and overweight lean groups. We conclude that (a) body composition, rather than body weight per se, is associated with increased cardiovascular disease risk factors; and (b) sex steroid alterations are related to body composition and are not an independent cardiovascular disease risk factor.

Adult↗
PubMed1986

Metabolic chromium balances in men.

A chromium (Cr) balance study was conducted on a metabolic unit for 12 days in two normal males, ages 62 and 66, ingesting a nutritionally adequate, constant diet. Complete urine and stool collections were obtained daily. The diet, stool, and urine were analyzed for chromium by Zeeman atomic absorption spectrometry. On dietary Cr intakes of 36.9 and 36.7 micrograms/day, only a small fraction of the ingested Cr, 0.9 microgram and 0.5 microgram/day, was absorbed. Most of the dietary Cr, 36.0 micrograms and 36.2 micrograms/day, was excreted in the stool. Urinary Cr was constant from day to day with a mean of 0.30 microgram/day +/- 0.03 SD and 0.28 microgram/day +/- 0.05 SD. The Cr balances (apparent net retention) were positive, 0.6 and 0.2 microgram/day, indicating equilibrium. The average apparent net absorption of Cr for the two subjects was 1.8%.

Chromium↗
PubMed1986

Serum insulin and blood pressure in an obese population.

Serum insulin has been implicated as a determinant of blood pressure (BP) level in obese hypertensive individuals. We examined the relationships among fasting insulin, mean arterial pressure (MAP), body composition, and fat distribution in 204 subjects unselected for glucose tolerance. All met the criteria of taking no oral hypoglycemic agents, insulin or antihypertensive medications. 95 percent were considered obese and 78 percent were female. Mean age was 39 years (range 15-71), percent ideal body weight (IBW) 171 percent (109-332), BP 125/81 mmHg (80-181/50-110) and fasting insulin 44 microU/ml (4-196). Lean body mass (LBM) and body fat were measured by tritium dilution. The correlation coefficient between insulin and MAP was 0.32 (P less than 0.0001). Both insulin and MAP correlated highly with percentage IBW, percentage body fat, fat mass, LBM, body build and upper fat pattern. Controlling for these variables simultaneously eliminated the association between insulin and BP. By contrast, the correlations between MAP and measures of body composition and fat distribution retained significance after controlling for insulin level. These findings suggest that measures of body composition and fat distribution have a relationship with BP that is not entirely accounted for by serum insulin level, and the relationship between serum insulin and BP is indirect and largely accounted for by their mutual association with measures of body composition and fat distribution.

Adipose Tissue↗
PubMed1986

Rapid enzymatic pretreatment of samples before determining chromium in serum or plasma.

A simplified method for preparing blood serum and plasma for Zeeman electrothermal atomic absorption spectrometry is described and applied to the measurement of chromium in human serum and plasma. This enzymatic degradation with bacterial protease (EC 3.4.21.3) requires little laboratory apparatus, decreases the work and time of sample preparation, and obviates some potential sources of contamination. We used bovine reference serum (USDA No. 7292) to validate Cr concentration. There was less Cr in serum than in plasma, whether sodium heparin or sodium citrate was used as anticoagulant. For six human subjects, Cr in serum averaged 0.15 (SD 0.02) micrograms/L, 0.26 (SD 0.03) micrograms/L in heparinized plasma, and 0.28 (SD 0.02) micrograms/L in citrated plasma. We postulate that the Cr concentration is lower in serum because some of the Cr binds to proteins complexed with the clot in the coagulation process.

Adult↗
PubMed1985

Effect of increased physical activity on voluntary intake in lean women.

To determine the effect of exercise-related factors on food intake, five nonobese women (mean +/- SEM of the percent of desirable body weight, 97 +/- 5) were hospitalized as part of a metabolic experiment. Excess amounts of a mixed food diet were provided on platters to the subjects. They served themselves from these and ate freely. Intake was estimated covertly by weighing the platters before and after serving. Expenditure was monitored with daily activity diaries and indirect calorimetry determinations of all the activities recorded. After a five-day evaluation phase, each subject underwent three 19-day treatment periods in which physical activity was modified. Total daily expenditure was increased to 114 +/- 4% of the sedentary treatment for a mild exercise period and 129 +/- 3% for a moderate period. Corresponding voluntary intakes during exercise were 117 +/- 5% and 122 +/- 6% of sedentary treatment. Although moderate exercise (mean 772 +/- 40 kcal/d) was greater than mild (378 +/- 63 kcal/d), the increased intake levels of the two were comparable. However, the resulting energy balances of 10 +/- 71 kcal/d for sedentary, 64 +/- 43 kcal/d for mild and -116 +/- 92 kcal/d for moderate treatments were not different. Therefore, in a paradigm which permits maintenance of a voluntary balanced energy state during an inactive period, compensatory intake responses to exercise occur. Unlike obese women who do not match their intakes to energy expended as physical activity, nonobese women demonstrate hyperphagic responses.

Adult↗