Habitual isomaltulose intake reduces arterial stiffness associated with postprandial hyperglycemia in middle-aged and elderly people: a randomized controlled trial.

Endothelin-1 (ET-1), produced by vascular endothelial cells, plays a pivotal role in the regulation of vascular tone. Isomaltulose, a naturally occurring sweetener and structural isomer of sucrose, reduces postprandial hyperglycemia, but its effect on arteriosclerosis due to hyperglycemia is unknown. The effects of 12 weeks of isomaltulose administration on ET-1 levels, a peptide that regulates arterial stiffness, blood pressure, and vascular tone, were tested before and after an oral glucose tolerance test. Fifty-four healthy middle-aged and older adults (30 men and 24 women) were divided into two groups: (1) a 25 g isomaltulose jelly drink intake group (Group I, 27 participants, mean age 55 ± 1 years) and (2) a sucrose jelly drink intake group (Group S, 27 participants, mean age 55 ± 1 years), each consuming isomaltulose or sucrose daily for 12 weeks, and a randomized, controlled study was conducted. Participants visited the laboratory before the intervention and 4, 8, and 12 weeks after the intervention to measure carotid-femoral (cf) and brachial-ankle (ba) pulse wave velocity (PWV), systolic blood pressure (BP), plasma glucose (PG), insulin, and ET-1 levels before and 60 and 120 min after a 75-g OGTT. baPWV, and ET-1 levels before intervention were significantly increased after 75-g OGTT compared to before 75-g OGTT in both groups (p < 0.05). The post-intervention baPWV, and ET-1 levels were significantly increased after 75-g OGTT in Group S compared to before 75-g OGTT (p < 0.05), whereas no significant changes were observed in Group I. These results suggest that consumption of isomaltulose, which has a lower GI than sucrose, is more effective in preventing the increases in systemic arterial stiffness associated with postprandial hyperglycemia in healthy middle-aged and older adults.

Effects of resistance training on bone mineral density and resting serum hormones in female collegiate distance runners: a randomized controlled pilot trial.

BACKGROUND: Studies report low bone mineral density (BMD) in female distance runners. We aimed to investigate changes in BMD and resting serum hormones, including dehydroepiandrosterone sulfate (DHEA-S) and estradiol (E2), before and after resistance training (RT) interventions in female collegiate distance runners. METHODS: Fourteen female collegiate distance runners (age, 19.8±0.8 years) and 14 age-matched healthy young women as controls (age, 20.5±1.6 years) were included and divided into RT groups and controls (runner with RT, RRT; runner controls, RCON; non-athlete with RT, NRT; non-athlete controls, NCON). The RRT and NRT groups performed squats and deadlifts at 60-85% 1RM load for one session of five sets of five repetitions, twice a week for 16 weeks. BMD of the total body, lumbar spine L2-L4, and femoral neck was measured by dual-energy X-ray absorptiometry scanning. Resting serum cortisol, adrenocorticotropic hormone, testosterone, growth hormone, insulin-like growth factor 1, DHEA-S, progesterone, E2, procollagen type I N-terminal propeptide (P1NP), and N-terminal telopeptide were assayed. RESULTS: The results showed a significant increase in total body BMD in both the RRT and NRT (both P<0.05) groups. P1NP in the RRT group increased significantly after RT, and the increase was higher than in the RCON (P<0.05). Conversely, no significant changes were observed in resting blood hormone levels for all measurements in all groups (all P>0.05). CONCLUSIONS: These findings suggest that 16 weeks of RT in female collegiate distance runners may increase total body BMD.

Relationship of muscle power and bone mineral density with the α-actinin-3 R577X polymorphism in Japanese female athletes from different sport types: An observational study.

The aim of this study was to clarify the relationships between muscle power and bone mineral density (BMD) and the α-actinin-3 (ACTN3) R577X polymorphism in Japanese female collegiate athletes participating in sports with various mechanical-load characteristics. This study included 260 female collegiate athletes involved in 10 competitive sports and 26 controls (mean ages, 19.2 ±â€…1.2 and 19.7 ±â€…1.3 years, respectively). The sports were classified into 3 categories (low-impact, multidirectional, and high-impact) based on the exercise load characteristics. Data on sports participation and competition experience were obtained through a questionnaire-type survey. The maximum anaerobic power (MAnP) test was performed to measure muscle power. The total body BMD was measured using dual-energy X-ray absorptiometry. The ACTN3 R577X polymorphism (rs1815739) was analyzed using a TaqMan® assay. The multidirectional sports participants with the RR genotype of the ACTN3 R577X polymorphism had a higher BMD than those with the RX and RX + XX genotypes (P = .018 and P = .003, respectively). The RR genotype was also associated with a higher MAnP than those with the RX + XX genotypes (P = .035). No other variables related to BMD and MAnP were significantly different. Our results suggests that the RR genotype may confer high trainability for BMD and muscle power in Japanese female collegiate athletes participating in multidirectional sport types. However, these associations were not found in the athletes participating in the low- and high-impact sport types.