No abstract

♦ Background: Fructo-oligosaccharides (FOS) exhibit soluble-fiber properties that beneficially affect bowel function and relieve constipation. The effects of FOS supplementation on constipation and biochemical parameters were examined in elderly continuous ambulatory peritoneal dialysis (CAPD) patients. ♦ Methods: This randomized, double-blind, placebocontrolled, cross-over study was performed in elderly CAPD patients (5 males and 4 females) with chronic constipation. All subjects were randomly assigned to receive either 20 g FOS or placebo daily for 30 days. After a 14-day washout period, the patients were switched to the other substance for 1 more month. Before and after each treatment period, frequency of defecation, characteristics of feces, and colonic transit were evaluated. Biochemical parameters were also assessed. ♦ Results: Fructo-oligosaccharides significantly increased the frequency of defecation (10.5 ± 2.0 vs 6.2 ± 1.4 times per week, p < 0.005) and changed the feces' appearance from type 1 (nut-like) to type 4 (sausage-like). The colonic transit determined by geometric center (GC) was augmented after FOS supplementation (3.9 ± 0.3 vs 3.2 ± 0.4, p < 0.05). Fructo-oligosaccharides had no effects on biochemical parameters. Fructo-oligosaccharides caused mild discomforts which were well tolerated after dose adjustment. ♦ Conclusions: Fructo-oligosaccharide supplementation is effective, well tolerated, and can be an alternative to other laxatives in CAPD patients with constipation. Further studies are needed to better assess the biochemical effects of FOS in the chronic kidney disease population.

While a short, intense bout of exercise increased pro-inflammatory mediators of the immune system, decreasing fat intake to 19% on a caloric deficient diet caused a greater increase in plasma TNF-alpha, sVCAM-1 and sICAM-1 concentration than the 30% and 50% fat diets in male and female subjects. Increasing fat calories to 50% with caloric balance did not exacerbate pro-inflammatory mediators compared to a 30% fat diet.

A low fat diet (19%) may not provide sufficient calories, essential fatty acids, and some micronutrients (especially vitamin E and zinc) for healthy untrained individuals, and it also lowered ApoA1 and HDL-C. Increasing fat intake to 50% of calories improved nutritional status, and did not negatively affect certain cardiovascular risk factors.

There is no consensus on the best diet for exercise, as many variables influence it. We propose an approach that is based on the total energy expenditure of exercise and the specific macro- and micronutrients used. di Prampero quantified the impact of intensity and duration on the energy cost of exercise. This can be used to determine the total energy needs and the balance of fats and carbohydrates (CHO). There are metabolic differences between sedentary and trained persons, thus the total energy intake to prevent overfeeding of sedentary persons and underfeeding athletes is important. During submaximal sustained exercise, fat oxidation (FO) plays an important role. This role is diminished and CHO's role increases as exercise intensity increases. At super-maximal exercise intensities, anaerobic glycolysis dominates. In the case of protein and micronutrients, specific recommendations are required. We propose that for submaximal exercise, the balance of CHO and fat favors fat for longer exercise and CHO for shorter exercise, while always maintaining the minimal requirements of each (CHO: 40% and fat: 30%). A case for higher protein (above 15%) as well as creatine supplementation for resistance exercise has been proposed. One may also consider increasing bicarbonate intake for exercise that relies on anaerobic glycolysis, whereas there appears to be little support for antioxidant supplementation. Insuring minimal levels of substrate will prevent exercise intolerance, while increasing some components may increase exercise tolerance.