Our findings suggest that prebiotics affect the intestinal microbiota and might maintain the antibody titers in elderly individuals.

In Japan, the incidence of heat illness in older people has rapidly increased during midsummer in the last decade, and we suggested that whey-protein+carbohydrate supplementation during aerobic training would increased plasma volume (PV) to enhance thermoregulatory adaptation in older men ( J Appl Physiol 107: 725-733, 2009); however, >60% of people age 65 and older suffer from hypertension, and the symptoms may be worsened by hypervolemia. To examine this, we randomly divided 21 older men (∼69 yr) with ∼160 mmHg for systolic and ∼90 mmHg for diastolic blood pressure at rest into two groups: Glc ( n = 11) consuming glucose alone (25 g) and Pro-Glc ( n = 10) consuming whey protein (10 g) + glucose (15 g), immediately after cycling exercise at 60–75% of peak aerobic capacity (V̇o2 peak) for 60 min/day, 3 days/wk, for 8 wk. Before and after training, we measured PV (dye dilution), baroreflex sensitivity (BRS) of heart rate (Valsalva maneuver), and carotid arterial compliance (CAC) from carotid arterial diameter (ultrasound imaging) responses to pulsatile arterial pressure change (photoplethysmography) at rest. Additionally, we measured esophageal temperature (Tes) and forearm skin blood flow (plethysmography) during exercise at 60% pretraining V̇o2 peak for 20 min in a warm environment. We found that the forearm skin vascular conductance response to increased Tes was enhanced in Pro-Glc with increased PV, but this was not found in Glc; however, despite the increased PV, arterial blood pressures rather decreased with increased CAC and BRS in Pro-Glc. Thus, the prescription was applicable to older men with hypertension to prevent heat illness during exercise.

No abstract

This study aimed to investigate the effects of a combination of a dairy product fermented by lactobacilli (DFL) and galactooligosaccharides (GOS) on mineral balances in growing rats with hypochlorhydria induced by a proton pump inhibitor (PPI). Three-week-old male rats were assigned to receive one of six diets: a control diet, control diets containing 1.6 or 5.0 % GOS, a DFL diet and DFL diets containing 1.6 or 5.0 % GOS for 9 days. From day 5 of the feeding period, half of the rats fed with control diets were subcutaneously administered with saline, whereas the remaining rats were administered with PPI for 5 days. Calcium (Ca), phosphorus (P), magnesium (Mg), iron (Fe) and zinc (Zn) balances were determined from days 6 to 9. PPI administration significantly decreased the apparent absorption of Ca and Fe and increased urinary P excretion, resulting in decreased Ca, Fe and P retention. GOS dose-dependently increased the apparent absorption of Ca, Mg and Fe and urinary Mg excretion and decreased urinary P excretion. DFL significantly increased the apparent absorption of Ca and Mg and urinary Mg excretion. The combination of DFL and GOS additively affected these parameters, resulting in increased Ca, P and Fe retention, and it further increased the apparent absorption and retention of Zn at 5.0 % GOS. In conclusion, the combination of DFL and GOS improves Ca, P and Fe retention in an additive manner and increases the Zn retention in growing rats with hypochlorhydria induced by PPI.

The purpose of the present study is to investigate the effects of hypochlorhydria induced by proton pump inhibitor (PPI) administration and intake of a dairy product fermented by lactobacilli (DFL) on bone metabolism in growing rats. Male rats, aged 3 weeks, were divided into two groups: a control group fed a casein-based diet and a group fed a DFL-based diet. Each group was fed its respective experimental diets for 9 d. At day 5 of the feeding period, each group was divided into two subgroups: one that received a saline injection and one that received a PPI injection. Rats were subcutaneously administered saline or PPI for 5 d. Faecal Ca excretion was determined from day 6 to day 9. At the end of the experiment, plasma and femurs were collected. Administration of PPI significantly decreased bone mineral density (shown by X-ray computerised tomography) and bone strength (shown by a three-point bending test) in the control group. Plasma osteocalcin, type I collagen C-telopeptides, 1,25-dihydroxyvitamin D and parathyroid hormone concentrations were elevated by PPI administration in the control group. Faecal Ca excretion and urinary P excretion in the control group were remarkably increased by PPI administration. On the other hand, these adverse effects of PPI were not observed in the DFL group. These results suggest that hypochlorhydria-induced bone loss may result from high bone turnover induced by secondary hyperparathyroidism due to Ca malabsorption and that DFL intake cancels these adverse effects probably via improving Ca malabsorption in growing rats.Key words: Hypochlorhydria: Fermented milk: Bone: Calcium Most physiological functions decline progressively with age. Gastric acid secretion also decreases with advancing age in humans (1) and rats (2,3) . Recently, Aoki et al. reported that chronic atrophic gastritis, a factor of hypochlorhydria, is very common among the elderly (4) .There are some studies suggesting the association between hypochlorhydria and bone loss. Many researchers have reported that gastrectomy induces bone loss in rats (5 -8) and human subjects (9 -12) . However, gastrectomy in itself has multiple risk factors other than hypochlorhydria for bone loss. For example, the production of the stomach hormone ghrelin, which is involved in bone physiology, is suppressed by gastrectomy (13) . Some studies have shown that the use of proton pump inhibitors (PPI), the most potent acid-suppressing drugs, is associated with an increased risk of hip fracture (14,15) . However, there is limited research showing the effects of hypochlorhydria induced by PPI on bone metabolism in human subjects or animals.The absorbability of Ca is dependent on its solubility. The acidity in the stomach and resulting chyme increases Ca solubility (16) . Thus, hypochlorhydria is considered to have a potential adverse effect on bone metabolism via the inhibition of Ca absorption.The usefulness of cows' milk (17,18) or dairy products including cows' milk and yogurt (19) for the prevention of osteoporosis has been ...