Search PubMed⌕ Search

Biomedical subjects

V Vuksan

Publications and source records attributed to V Vuksan.

49 records · Page 3Linked to original sources
PubMed1992

Beneficial effect of low-glycemic index diet in overweight NIDDM subjects.

OBJECTIVE: To determine whether low-glycemic index (GI) diets have clinical utility in overweight patients with non-insulin-dependent diabetes mellitus (NIDDM). RESEARCH DESIGN AND METHODS: Six patients with NIDDM were studied on both high- and low-GI diets of 6-wk duration with metabolic diets with a randomized crossover design. Both diets were of similar composition (57% carbohydrate, 23% fat, and 34 g/day dietary fiber), but the low-GI diet had a GI of 58 compared with 86 for the high-GI diet. RESULTS: Small and similar amounts of weight were lost on both diets: 2.5 kg on high-GI diet and 1.8 kg on low-GI diet. On the low-GI diet, the mean level of serum fructosamine, as an index of overall blood glucose control, was lower than on the high-GI diet by 8% (P less than 0.05), and total serum cholesterol was lower by 7% (P less than 0.01). CONCLUSIONS: In overweight patients with NIDDM, reducing diet GI improves overall blood glucose and lipid control.

Blood Glucose↗
PubMed1991

Effect of method of administration of psyllium on glycemic response and carbohydrate digestibility.

To determine whether there was any advantage to taking a soluble fiber supplement separate from food, as opposed to incorporated into a food, we used psyllium as a model, either taken in water just before a flaked bran cereal test meal, sprinkled on top of the cereal, or actually incorporated into the flake. In normal subjects, psyllium reduced the glycemic response when sprinkled onto or incorporated into the cereal, but not when taken before the cereal. Varying the amount of psyllium incorporated into the cereal from 0 to 20% resulted in a linear dose-dependent reduction of the glycemic index (GI) (GI = 101 -2.2 x % psyllium; r = 0.950; p less than 0.002). In subjects with diabetes, the blood-glucose-lowering effect of the psyllium flake cereal was similar to that in normal subjects. Mixing psyllium with the cereal or incorporating it into the cereal reduced the rate of digestion of bran flakes in vitro but was not associated with increased breath hydrogen levels in vivo as an index of rapid colonic fermentation. The bran flakes with psyllium incorporated was rated as no less palatable than the bran flakes cereal alone, and significantly more palatable (p less than 0.05) than taking psyllium in water before the cereal or sprinkling psyllium onto the cereal. These studies confirm earlier reports that viscous fibers must be intimately mixed with the food to have the effect of reducing blood glucose responses, and that the mechanism of action relates to a reduced rate of digestion rather than carbohydrate malabsorption.(ABSTRACT TRUNCATED AT 250 WORDS)

Adult↗
PubMed1991

Specific types of colonic fermentation may raise low-density-lipoprotein-cholesterol concentrations.

To assess the effects of increased colonic fermentation on serum lipids, eight healthy volunteers were placed on two identical 2-wk metabolic diets, one of which was supplemented with lactulose (18-25 g/d). Lactulose raised day-long concentrations of breath hydrogen and serum glutamine as indicators of increased colonic fermentation by 78 +/- 13% (P less than 0.001) and 24.7 +/- 9.5% (P less than 0.05), respectively). Unexpectedly, however, fasting serum total and low-density-lipoprotein cholesterol and apolipoprotein B concentrations were higher at 2 wk by 8.9 +/- 1.5% (P less than 0.001), 10.9 +/- 2.2% (P less than 0.005), and 18.9 +/- 5.9% (P less than 0.02), respectively, compared with the control diet. With lactulose, mean free fatty acid concentrations were reduced over the day by 19.5 +/- 5.9% (P less than 0.02), with no change in mean day-long blood glucose, serum insulin, or C-peptide concentrations. We conclude that certain rapidly fermented substrates may raise rather than lower serum lipids, possibly through increasing the amount of acetate absorbed from the colon.

Acetates↗
PubMed1991

Is colonic fermentation minimized by increasing meal frequency?

It has been suggested that, although increasing meal frequency has metabolic advantages in terms of carbohydrate and lipid metabolism, the efficiency of small intestinal absorption may be enhanced, thus reducing the extent of colonic fermentation. Since this may be undesirable, we have tested whether increasing meal frequency reduces the amount of carbohydrate fermented into the colon. Accordingly, seven healthy male volunteers took, in random order, two identical 2-week metabolic diets divided into either seventeen or three meals daily. On day 13 of each period measurements were made throughout the day of breath H2 and serum acetate, as markers of colonic fermentation. Mean levels of both breath H2 and acetate were similar on both diets, being lower on nibbling by 3.2 +/- 0.8 ppm and 25 +/- 9 mumols/l respectively (not significant). This study failed to demonstrate an effect of more efficient carbohydrate absorption with increased meal frequency.

Acetates↗
PubMed1990

Metabolic effects of reducing rate of glucose ingestion by single bolus versus continuous sipping.

Modifying the rate of absorption has been proposed as a therapeutic principle of specific relevance to diabetes. To demonstrate clearly the metabolic benefits that might result from reducing the rate of nutrient delivery, nine healthy volunteers took 50 g glucose in 700 ml water on two occasions: over 5-10 min (bolus) and at a constant rate over 3.5 h (sipping). Despite similar 4-h blood glucose areas, large reductions were seen in serum insulin (54 +/- 10%, P less than 0.001) and C-peptide (47 +/- 12%, P less than 0.01) areas after sipping, together with lower gastric inhibitory polypeptide and enteroglucagon levels and urinary catecholamine output. There was also prolonged suppression of plasma glucagon, growth hormone, and free-fatty acid (FFA) levels after sipping, whereas these levels rose 3-4 h after the glucose bolus. An intravenous glucose tolerance test at 4 h demonstrated a 48 +/- 10% (P less than 0.01) more rapid decline in blood glucose (Kg) after sipping than after the bolus. Furthermore, FFA and total branched-chain amino acid levels as additional markers of insulin action were lower over this period despite similar absolute levels of insulin and C-peptide. These findings indicate that prolonging the rate of glucose absorption enhances insulin economy and glucose disposal.

Administration, Oral↗
PubMed1990

Glycemic index of foods in individual subjects.

We studied 12 subjects with diabetes to determine how well the glycemic index (GI) predicted the ranking of glycemic responses of different foods in individuals. All subjects ate three mixed meals (bread, rice, or spaghetti with GIs of 100, 79, and 61, respectively) four times in a randomized complete block design. The mean glycemic response areas of the different meals ranked according to the predicted GI in every individual. The observed mean +/- SD GI values of the meals were significantly different from each other (bread 100 +/- 7, rice 75 +/- 9, spaghetti 54 +/- 9), with no significant difference in response between subjects. It is concluded that individuals share common mean GI values for different foods. Within confidence limits determined by the variability of glycemic responses, the number of repeated tests conducted, and the expected GI difference, the GI can be used to predict the ranking of the mean glycemic responses of mixed meals taken by individuals.

Adult↗
PubMed1989

Nibbling versus gorging: metabolic advantages of increased meal frequency.

We studied the effect of increasing the frequency of meals on serum lipid concentrations and carbohydrate tolerance in normal subjects. Seven men were assigned in random order to two metabolically identical diets. One diet consisted of 17 snacks per day (the nibbling diet), and the other of three meals per day (the three-meal diet); each diet was followed for two weeks. As compared with the three-meal diet, the nibbling diet reduced fasting serum concentrations of total cholesterol, low-density lipoprotein cholesterol, and apolipoprotein B by a mean (+/- SE) of 8.5 +/- 2.5 percent (P less than 0.02), 13.5 +/- 3.4 percent (P less than 0.01), and 15.1 +/- 5.7 percent (P less than 0.05), respectively. Although the mean blood glucose level and serum concentrations of free fatty acids, 3-hydroxybutyrate, and triglyceride were similar during both diets, during the nibbling diet the mean serum insulin level decreased by 27.9 +/- 6.3 percent (P less than 0.01) and the mean 24-hour urinary C-peptide output decreased by 20.2 +/- 5.6 percent (P less than 0.02). In addition, the mean 24-hour urinary cortisol excretion was lower by 17.3 +/- 5.9 percent (P less than 0.05) at the end of the nibbling diet than at the end of the three-meal diet. The blood glucose, serum insulin, and C-peptide responses to a standardized breakfast and the results of an intravenous glucose-tolerance test conducted at the end of each diet were similar. We conclude that in addition to the amount and type of food eaten, the frequency of meals may be an important determinant of fasting serum lipid levels, possibly in relation to changes in insulin secretion.

3-Hydroxybutyric Acid↗
PubMedDate not supplied

Effect of cocoa bran on low-density lipoprotein oxidation and fecal bulking.

BACKGROUND: Legumes have reported benefits in terms of reduced risk for coronary heart disease and of colonic health. A novel legume fiber, cocoa bran, also may have favorable health effects on serum lipid levels, low-density lipoprotein (LDL) cholesterol oxidation, and fecal bulk. METHODS: Twenty-five healthy normolipidemic subjects (13 men and 12 women) (mean +/- SEM age, 37 +/- 2 years; mean +/- SEM body mass index [calculated as weight in kilograms divided by the square of height in meters], 24.6 +/- 0.7) ate cocoa-bran and chocolate-flavored low-fiber breakfast cereals for 2-week periods, with 2-week washout, in a double-blind crossover study. The cocoa-bran cereal provided 25.0 g/d of total dietary fiber (TDF). The low-fiber cereal (5.6 g/d TDF) was of similar appearance and energy value. Fasting blood samples were obtained at the start and end of each period, and 4-day fecal collections were made from days 11 through 14. RESULTS: High-density lipoprotein (HDL) cholesterol level was higher (7.6% +/- 2.9%; P =.02) and the LDL/HDL cholesterol ratio was lower (6.7% +/- 2.3%; P =.007) for cocoa-bran compared with low-fiber cereal at 2 weeks. No effect was seen on LDL cholesterol oxidation. Mean fecal output was significantly higher for cocoa-bran than for low-fiber cereal (56 +/- 14 g/d; P<.001) and equal to the increase seen in the same subjects with wheat fiber in a previous study. CONCLUSIONS: A chocolate-flavored cocoa-bran cereal increased fecal bulk similarly to wheat bran and was associated with a reduction in the LDL/HDL cholesterol ratio. In view of the low-fat, high-fiber nature of the material, these results suggest a possible role for this novel fiber source in the diets of normal, hyperlipidemic, and constipated subjects.

Adult↗
PubMedDate not supplied

American ginseng improves glycemia in individuals with normal glucose tolerance: effect of dose and time escalation.

OBJECTIVE: We studied the effect of escalating the dose and administration time of American ginseng (AG, Panax quinquefolius L.) in nondiabetic individuals to achieve further improvements in glucose tolerance seen previously when 3 g of AG was taken 40 minutes before a 25 g glucose challenge. METHODS: Ten nondiabetic individuals (6M:4F; mean +/- STD: age = 41 +/- 13 years, BMI = 24.8 +/- 3.5 kg/m2, FBG = 4.5 +/- 0.1 mmol L(-1)) on 12 separate occasions, randomly received 0 (placebo), 3, 6 or 9 g of ground AG root at 40, 80, or 120 minutes before a 25 g oral glucose challenge. Capillary blood glucose was measured prior to ingestion of AG or placebo capsules and at 0, 15, 30, 45, 60 and 90 minutes from start of challenge. RESULTS: Compared with the placebo, 3, 6 and 9 g of AG reduced (p<0.05) postprandial incremental glucose at 30, 45 and 60 minutes; also, 3 and 9 g of AG did so at 90 minutes. At 60 minutes, 9 g of AG reduced incremental postprandial glucose relative to 3 g of AG (p<0.05). All AG doses reduced (p<0.05) area under the incremental glucose curve (3 g, 26.6%; 6 g, 29.3%; 9 g, 38.5%). AG taken at different times did not have an additional influence on postprandial glycemia. CONCLUSIONS: In nondiabetic individuals, 3, 6 or 9 g of AG taken 40, 80 or 120 minutes before a glucose challenge similarly improved glucose tolerance.

Adult↗
PubMedDate not supplied

Differences in risk factors, atherosclerosis and cardiovascular disease between ethnic groups in Canada: the study of health assessment and risk in ethnic groups (SHARE).

Cardiovascular disease rates vary greatly between ethnic groups in Canada. To establish whether this variation can be explained by differences in disease risk factors and subclinical atherosclerosis, we undertook a population-based study of three ethnic groups in Canada: South Asians, Chinese and Europeans. A total of 985 participants were recruited from three cities (Hamilton, Toronto and Edmonton) by stratified random sampling. Clinical cardiovascular disease was defined by history or electrocardiographic findings. Carotid atherosclerosis was measured with B-mode ultrasonography. Conventional (smoking, hypertension, diabetes, raised cholesterol) and novel risk factors (markers of a prothrombotic state) were measured. Within each ethnic group and overall, the degree of carotid atherosclerosis was associated with a higher prevalence of cardiovascular disease. South Asians had the highest prevalence of this condition compared with Europeans and Chinese (11%, 5% and 2%, respectively; p=0.0004). Despite this finding, Europeans had more atherosclerosis (mean of the maximum intimal medial thickness 0.75 [0.16] mm) than South Asians (0.72 [0.15] mm) and Chinese (0.69 [0.16] mm). South Asians had an increased prevalence of glucose intolerance, higher total and low-density lipoprotein cholesterol, higher triglycerides and lower high-density lipoprotein cholesterol, and much greater abnormalities in novel risk factors including higher concentrations of fibrinogen, homocysteine, lipoprotein(a), and plasminogen activator inhibitor-1. Although there are differences in conventional and novel risk factors between ethnic groups, this variation and the degree of atherosclerosis only partly explains the higher rates of cardiovascular disease among South Asians compared with Europeans and Chinese. The increased risk of cardiovascular events could be due to factors affecting plaque rupture, the interaction between prothrombotic factors and atherosclerosis, or as yet undiscovered risk factors.

Adult↗
PubMedDate not supplied

[Metabolic diseases and the high-fiber diet].

There is no doubt that fiber, in particular viscous dietary fiber, has a positive effect on human health both in the prevention and treatment of chronic diseases. Over 30 years of intensive clinical research with guar, psyllium, oat and other fiber-rich foods has repeatedly demonstrated the health benefits of dietary fiber in lowering insulin requirements and improving blood glucose control in diabetics, as well as reducing serum lipid levels in hyperlipidemics. Accumulating epidemiological evidence is also supporting the link between high-fiber diets and the reduction of risk for heart disease and cancer. As a result, increased dietary fiber is recommended by health authorities worldwide. However, the mechanism of fibers' action is not fully understood and the effect is not always consistent with the expected results. One of the reasons could be the large intra- and inter-fiber variability due to its complex structural and physicochemical characteristics. As a consequence, some of the health agencies focus their recommendations more on the type of dietary fat rather than a high carbohydrate/high-fiber.

Coronary Disease↗