Effect of energy restriction, weight loss, and diet composition on plasma lipids and glucose in patients with type 2 diabetes.
(25/2441)
OBJECTIVE: To determine the optimal diet for improving glucose and lipid profiles in obese patients with type 2 diabetes during moderate energy restriction. RESEARCH DESIGN AND METHODS: A total of 35 free-living obese patients with type 2 diabetes were assigned to one of three 1,600 kcal/day diets for 12 weeks. The diets were high carbohydrate (10% fat, 4% saturated), high monounsaturated fat (MUFA) (32% fat, 7% saturated), or high saturated fat (SFA) (32% fat, 17% saturated). RESULTS: Diet composition did not affect the magnitude of weight loss, with subjects losing an average of 6.6 +/- 0.9 kg. Energy restriction and weight loss resulted in reductions in fasting plasma glucose (-14%), insulin (-27%), GHb (-14%), and systolic (-7%) and diastolic blood pressure (-10%) levels and the glucose response area (-17%) independent of diet composition. Diet composition did affect the lipoprotein profile. LDL was 10% and 17% lower with the high-carbohydrate and high-MUFA diets, respectively, whereas no change was observed with the high-SFA diet (P < 0.001 for effect of diet). HDL was transiently reduced on the high-carbohydrate diet at weeks 1, 4, and 8, whereas higher fat consumption maintained these levels. The total cholesterol:HDL ratio, although significantly reduced on the high-MUFA diet (P < 0.01), was not different from the other two diets after adjustment for baseline differences. CONCLUSIONS: Energy restriction, independent of diet composition, improves glycemic control; however, reducing SFA intake by replacing SFA with carbohydrate or MUFA reduces LDL maximally during weight loss and to a greater degree than has been shown in weight-stable studies. (+info)
Konjac-mannan (glucomannan) improves glycemia and other associated risk factors for coronary heart disease in type 2 diabetes. A randomized controlled metabolic trial.
(26/2441)
OBJECTIVE: To examine whether Konjac-mannan (KJM) fiber improves metabolic control as measured by glycemia, lipidemia, and blood pressure in high-risk type 2 diabetic patients. RESEARCH DESIGN AND METHODS: A total of 11 hyperlipidemic and hypertensive type 2 diabetic patients treated conventionally by a low-fat diet and drug therapy participated. After an 8-week baseline, all were randomly assigned to take either KJM fiber-enriched test biscuits (0.7 g/412 kJ [100 kcal] of glucomannan) or matched placebo wheat bran fiber biscuits during two 3-week treatment phases separated by a 2-week washout period. The diet in either case was metabolically controlled and conformed to National Cholesterol Education Program Step 2 guidelines, while medications were maintained constant. Efficacy measures included serum fructosamine, lipid profiles, apolipoproteins, blood pressure, body weight, and nutritional analysis. RESULTS: Compared with placebo, KJM significantly reduced the metabolic control primary end points: serum fructosamine (5.7%, P = 0.007, adjusted alpha = 0.0167), total:HDL cholesterol ratio (10%, P = 0.03, adjusted alpha = 0.05), and systolic blood pressure (sBP) (6.9%, P = 0.02, adjusted alpha = 0.025). Secondary end points, including body weight, total, LDL, and HDL cholesterol, triglycerides, apolipoproteins A-1, B, and their ratio, glucose, insulin, and diastolic blood pressure, were not significant after adjustment by the Bonferroni-Hochberg procedure. CONCLUSIONS: KJM fiber added to conventional treatment may ameliorate glycemic control, blood lipid profile, and sBP in high-risk diabetic individuals, possibly improving the effectiveness of conventional treatment in type 2 diabetes. (+info)
Food preferences and reported frequencies of food consumption as predictors of current diet in young women.
(27/2441)
BACKGROUND: Self-reported food preferences and frequencies of food consumption have served as proxy measures of the current diet in consumer research and in nutritional epidemiology studies, respectively. OBJECTIVE: The objective was to determine whether food preferences and food-frequency scores are associated variables that are predictive of nutrient intakes. DESIGN: College-age women (n = 87) completed a 98-item food-frequency questionnaire and rated preferences for many of the same foods on a 9-point category scale. Estimated intakes of fat, fiber, and vitamin C were obtained by using 3-d food records. RESULTS: For virtually all item pairs tested, food preferences and reported frequencies of consumption of the same foods were significantly correlated with each other. The median Pearson correlation coefficient was 0.40 (range: -0.04 to 0.62). Correlations improved when foods were aggregated into factor-based food groups. The slope of the relation between food preferences and frequency of consumption varied with food category. Both food preferences and food frequencies predicted dietary outcomes. Fat consumption was predicted equally well by either approach in a multiple regression model. Intakes of fiber and vitamin C were better predicted by food-frequency scores than by stated preferences for vegetables and fruit. CONCLUSIONS: Reported frequencies of food consumption, the core of the food-frequency approach, were associated with food likes and dislikes. Food preferences were a predictor of dietary intakes and may provide an alternative to the food-frequency approach for dietary intake assessment. (+info)
Hamsters and guinea pigs differ in their plasma lipoprotein cholesterol distribution when fed diets varying in animal protein, soluble fiber, or cholesterol content.
(28/2441)
There were two objectives to these studies: 1) to compare the lipoprotein cholesterol distribution in two animal models in response to different dietary treatments and 2) to assess whether the hypercholesterolemia induced by high cholesterol intake could be reversed by consumption of vegetable-protein and/or dietary fiber. Guinea pigs, which carry the majority of plasma cholesterol in LDL, and hamsters, with a higher distribution of cholesterol in HDL, were evaluated in three different studies. In Study 1, animals were fed semi-purified diets for 4 wk with proportions of 60:40, 20:80 or 0:100 (w/w) of casein/ soybean protein. Hamsters and guinea pigs that consumed 100% soybean protein had lower plasma total cholesterol (TC) than those fed diets containing casein (P < 0.01). In Study 2, three doses of dietary pectin (2.7, 5.4, or 10.7 g/100g) added in place of cellulose were tested. Intake of 10.7 g/100 g pectin resulted in the lowest plasma TC concentrations for both species (P < 0.01). Although the TC lowering was similar in studies 1 and 2, the lipoprotein cholesterol distribution differed. Whereas the differences in plasma cholesterol were in LDL in guinea pigs, hamsters exhibited differences in both non-HDL and HDL cholesterol. In study 3, animals were fed 100% soybean protein, 10.7 g/100 g pectin, and three doses of dietary cholesterol: 0.04, 0.08, or 0.16 g/100 g, which is equivalent to 300, 600, or 1,200 mg/d in humans. Guinea pigs and hamsters had the highest plasma LDL and hepatic cholesterol concentrations when they consumed 0.16 g/100 g of cholesterol (P < 0.01). However, intake of 0.08 g/100 g of cholesterol resulted in lower plasma LDL cholesterol concentrations than did consuming high animal protein (60:40 casein/ soy) or low soluble fiber (2.7 g/100 g). Relatively high levels of dietary cholesterol combined with vegetable protein and soluble fiber resulted in desirable lipoprotein profiles in animal models that significantly differ in their lipoprotein cholesterol distribution. (+info)
Teas and other beverages suppress D-galactosamine-induced liver injury in rats.
(29/2441)
We compared the effects of various types of beverages (teas, coffee, and cocoa) on D-galactosamine-induced liver injury by measuring plasma alanine aminotransferase (ALT) and aspartate aminotransferase (AST) activities in 7-wk-old male Wistar rats. The effects of five fractions extracted with different organic solvents from green tea, different types of dietary fibers, and some short chain fatty acids were also investigated. All of the beverages tested significantly suppressed D-galactosamine-induced enhancement of plasma enzyme activities when powdered beverages were added to the diet (30 g/kg) and fed to rats for 2 wk. Plasma ALT activities were 1155 +/- 82 [micromol/(min.L), control], 289 +/- 61 (green tea), 626 +/- 60 (roasted green tea), 471 +/- 84 (puerh tea), 676 +/- 69 (oolon tea), 423 +/- 76 (black tea), 829 +/- 53 (coffee), and 885 +/- 89 (cocoa). The profile of AST activities was similar. The caffeine-containing fraction from green tea had no significant effect, whereas the other four fractions, including the soluble fiber fraction, significantly suppressed liver injury. In addition to tea fibers, many other types of dietary fiber (hemicellulose, chitin, chitosan, alginate, pectin, guar gum, glucomannan, and inulin, but not cellulose) had liver injury-preventive effects when added to the diet (30 g/kg), suggesting that liver injury-prevention may be one of the general effects of dietary fibers. Of three short-chain fatty acids tested (acetate, propionate, and butyrate), only acetate prevented liver injury when added to the diet (15 g/kg), supporting the possibility that the liver injury-preventive effect of dietary fibers may be mediated at least in part by certain organic acids. These results suggest that several beverages possess preventive effects on certain types of liver injury, such as that induced by D-galactosamine, and that different constituents of high and low molecular weights contribute to the liver injury-preventive effects of green tea. (+info)
Concepts in functional foods: the case of inulin and oligofructose.
(30/2441)
Recent advances in biosciences support the hypothesis that diet modulates various body functions. Diet may maintain well-being and reduce the risk of some diseases. Such discoveries have led to the concept of "functional food" and the development of the new discipline, i.e., "functional food science." A practical and simple definition of a "functional food" is a food for which a claim has been authorized. The food components to be discussed as potential "functional food ingredients" are the inulin-type fructans, i.e., chicory inulin and oligofuctose. The targets for their effects are the colonic microflora, the gastrointestinal physiology, the immune functions, the bioavailability of minerals, the metabolism of lipids and colonic carcinogenesis. Potential health benefits include reduction of risk of colonic diseases, noninsulin-dependent diabetes, obesity, osteoporosis and cancer. The documentation of such benefits requires scientific evidence that must be evaluated in terms of "health claims." Previous assessments have concluded that, in terms of "functional claims," strong evidence exists for a prebiotic effect and improved bowel habit. The evidence for calcium bioavailability is promising, and positive modulation of triglyceride metabolism is undergoing preliminary evaluation. Scientific research still must be done to support any "disease risk reduction claim," but sound hypotheses do already exist for designing the relevant human nutrition trials. (+info)
Inulin and oligofructose: what are they?
(31/2441)
Inulin is a term applied to a heterogeneous blend of fructose polymers found widely distributed in nature as plant storage carbohydrates. Oligofructose is a subgroup of inulin, consisting of polymers with a degree of polymerization (DP) +info)
Inulin and oligofructose: safe intakes and legal status.
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Inulin and oligofructose are a significant part of the daily diet of most of the world's population. Daily intakes for the U.S. and Europe have been estimated at up to 10 g, specifically 1-4 g for the 97th percentile in the U.S. Because both inulin and oligofructose are macroingredients, it is difficult to apply classical toxicology tests. Although some high dose animal tests have been performed, none have revealed any toxic effects. The safety of inulin and oligofructose for use in foods was evaluated by many legal authorities worldwide. As a result, both inulin and oligofructose are accepted in most countries as food ingredients that can be used without restrictions in food formulations. In the U.S., a panel of experts performed a generally accepted as safe (GRAS) Self-Affirmation Evaluation in 1992 and concluded similarly. At high doses, increased flatulence and osmotic pressure can cause intestinal discomfort. These doses vary widely from person to person and also depend on the type of food in which inulin or oligofructose is incorporated. With regard to labeling, both inulin and oligofructose are gradually being accepted as "dietary fibers" in most countries around the world. The mention of their "bifidogenic effect" on food labels has also been legally accepted in several countries. (+info)