The Effect of a Citrus and Pomegranate Complex on Physical Fitness and Mental Well-Being in Healthy Elderly: A Randomized Placebo-Controlled Trial.

OBJECTIVES: This study investigates whether a citrus and pomegranate complex (CPC) improves physical fitness, mental well-being, and blood biomarkers for oxidative stress and endothelial function in healthy elderly. DESIGN: A randomized placebo-controlled cross-over trial. PARTICIPANTS: The study included 36 healthy elderly aged 60-75 years old. INTERVENTION AND MEASUREMENTS: Participants received four weeks of CPC supplementation and performed the handgrip strength and senior fitness test. Quality of life (QOL) was assessed and blood samples were analyzed for oxidative stress and endothelial function markers. RESULTS: After four weeks of CPC supplementation, handgrip strength significantly improved (p=0.019), compared to placebo. Moreover, the thinking, memory, learning, and concentration facets were improved (p=0.042), compared to placebo, and plasma malondialdehyde decreased, compared to placebo (p=0.033). The intervention did not affect senior fitness and the other QOL domains and blood parameters. CONCLUSION: Four weeks of daily CPC supplementation significantly improves handgrip strength and self-evaluated measures of psychological function in healthy older adults. Further research should focus on mechanisms associated with physical performance.

Ileal brake activation: macronutrient-specific effects on eating behavior?

BACKGROUND: Activation of the ileal brake, by infusing lipid directly into the distal part of the small intestine, alters gastrointestinal (GI) motility and inhibits food intake. The ileal brake effect on eating behavior of the other macronutrients is currently unknown. OBJECTIVE: The objective of this study was to investigate the effects of ileal infusion of sucrose and casein on food intake, release of GI peptides, gastric emptying rate and small-bowel transit time with safflower oil as positive control. DESIGN: This randomized, single-blind, crossover study was performed in 13 healthy subjects (6 male; mean age 26.4±2.9 years; mean body mass index 22.8±0.4 kg m(-2)) who were intubated with a naso-ileal catheter. Thirty minutes after the intake of a standardized breakfast, participants received an ileal infusion, containing control ((C) saline), safflower oil ((HL) 51.7 kcal), low-dose casein ((LP) 17.2 kcal) or high-dose casein ((HP) 51.7 kcal), low-dose sucrose ((LC) 17.2 kcal) and high-dose sucrose ((HC) 51.7 kcal), over a period of 90 min. Food intake was determined during an ad libitum meal. Visual analogue score questionnaires for hunger and satiety and blood samples were collected at regular intervals. RESULTS: Ileal infusion of lipid, protein and carbohydrate resulted in a significant reduction in food intake compared with control (HL: 464.3±90.7 kcal, P<0.001; HP: 458.0±78.6 kcal, P<0.005; HC: 399.0±57.0 kcal, P<0.0001 vs control: 586.7±70.2 kcal, P<0.001, respectively). A reduction in energy intake was still apparent when the caloric amount of infused nutrients was added to the amount eaten during the ad libitum meal.Secretion of cholecystokinin and peptide YY but not of glucagon-like peptide-1 (7-36) was increased during ileal perfusion of fat, carbohydrates and protein. During ileal perfusion of all macronutrients, a delay in gastric emptying and intestinal transit was observed, but differences were not significant compared with control. CONCLUSION: Apart from lipids, also sucrose and casein reduce food intake on ileal infusion, thereby activating the ileal brake. In addition to food intake, also satiety and GI peptide secretion were affected.

The effects of butyrate enemas on visceral perception in healthy volunteers.

Fermentation of dietary fibres by colonic microbes leads to the production of short chain fatty acids (mainly propionate, butyrate and acetate), which are utilized by the colonic mucosa. Previous studies showed positive effects of butyrate on parameters of oxidative stress, inflammation and apoptosis. Recent studies in rats, however, showed that butyrate increased visceral sensitivity. The aim of this study was to determine the effects of physiologically relevant concentrations of butyrate on visceral perception in healthy human subjects. Eleven healthy volunteers participated in this randomized double-blind, placebo controlled cross-over study. The study consisted of three periods of 1 week each, in which the volunteers daily self-administered rectal enemas containing 100, 50 mmol L(-1) butyrate, or placebo (saline) prior to sleeping. A rectal barostat measurement was performed at the start and the end of each test period for the measurement of pain, urge and discomfort. Butyrate treatment resulted in a dose-dependent reduction of pain, urge and discomfort throughout the entire pressure range of the protocol. At a pressure of 4 mmHg, 50 and 100 mmol L(-1) butyrate concentrations resulted in a 23.9% and 42.1% reduction of pain scores, respectively, and the discomfort scores decreased by 44.2% and 69.0% respectively. At a pressure of 67 mmHg, 50 and 100 mmol L(-1) of butyrate decreased the pain scores by 23.8% and 42%, respectively, and discomfort scores 1.9% and 5.2% respectively. Colonic administration of butyrate, at physiologically relevant concentrations, dose-dependently decreases visceral sensitivity in healthy volunteers.

Review article: the role of butyrate on colonic function.

BACKGROUND: Butyrate, a short-chain fatty acid, is a main end-product of intestinal microbial fermentation of mainly dietary fibre. Butyrate is an important energy source for intestinal epithelial cells and plays a role in the maintenance of colonic homeostasis. AIM: To provide an overview on the present knowledge of the bioactivity of butyrate, emphasizing effects and possible mechanisms of action in relation to human colonic function. METHODS: A PubMed search was performed to select relevant publications using the search terms: 'butyrate, short-chain fatty acid, fibre, colon, inflammation, carcinogenesis, barrier, oxidative stress, permeability and satiety'. RESULTS: Butyrate exerts potent effects on a variety of colonic mucosal functions such as inhibition of inflammation and carcinogenesis, reinforcing various components of the colonic defence barrier and decreasing oxidative stress. In addition, butyrate may promote satiety. Two important mechanisms include the inhibition of nuclear factor kappa B activation and histone deacetylation. However, the observed effects of butyrate largely depend on concentrations and models used and human data are still limited. CONCLUSION: Although most studies point towards beneficial effects of butyrate, more human in vivo studies are needed to contribute to our current understanding of butyrate-mediated effects on colonic function in health and disease.

Gastric digestion of bovine lactoferrin in vivo in adults.

Lactoferrin (LF), an iron-binding glycoprotein present in milk and other endocrine and exocrine secretions, may exert a number of physiologic effects in the intestines. To study the effects of oral LF supplementation in vivo in the gastrointestinal tract, information about the gastric survival of LF in vivo is important. We tested 12 healthy volunteers (age 21 +/- 0.3 y) on 3 separate d according to a randomized, cross-over design. A test drink containing 4.5 g of bovine LF (20% iron-saturated LF; apoLF) in the presence of a gastric pH buffer (0.1 mol/L sodium citrate/citric acid; apoLFbuf), apoLF without the buffer (apoLF) or iron-saturated LF (holoLF) was administered into the stomach using nasogastric intubation. Gastric emptying rate, determined by a marker dilution technique, did not differ among any of these drinks. Gastric survival of LF, analyzed by gel permeation chromatography under denaturing conditions, was 64%, 62% and 79% after consumption of the apoLFbuf, apoLF and holoLF test drinks, respectively. Addition of the gastric pH buffer initially lowered intragastric pH because of its hydroxide buffering effect. However, it did not elevate intragastric pH over a prolonged period and thereby inhibit intragastric LF breakdown. We conclude that after oral administration, substantial amounts of apoLF and holoLF survive gastric transit.