Obese subjects with impaired glucose tolerance (IGT) are more susceptible than healthy individuals to oxidative stress and cardiovascular disease. This randomised controlled investigation was designed to test the hypothesis that α-lipoic acid supplementation and exercise training may elicit favourable clinical changes in obese subjects with IGT. All data were collected from 24 obese (BMI ≥ 30 kg/m2) IGT patients. Following participant randomisation into two groups, fasting venous blood samples were obtained at baseline, and before and following intervention. The first group consisted of 12 participants who completed a 12 week control phase followed by 12 weeks of chronic exercise at 65% HRmax for 30 minutes a day, 5 days per week, while ingesting 1 gram per day of α-lipoic acid for 12 weeks. The second group consisted of 12 participants who completed the same 12 week control phase, but this was followed by 12 weeks of 1 gram per day of α-lipoic acid supplementation only (no exercise). The main findings show a comparatively greater rate of low density lipoprotein (LDL) oxidation in the group consisting of α-lipoic acid only (p < 0.05 vs. pre intervention), although total oxidant status was lower post intervention (p < 0.05 vs. baseline) in this group. However, exercise and α-lipoic acid in combination attenuates LDL oxidation. Furthermore, in the α-lipoic acid supplement plus exercise training group, total antioxidant capacity was significantly increased (p < 0.05 vs. baseline and pre intervention). Body fat percentage and waist and hip circumference decreased following exercise training (p < 0.05 vs. post intervention). There were no selective treatment differences for a range of other clinical outcomes including glycaemic regulation (p > 0.05). These findings report that α-lipoic acid ingestion may increase the atherogenicity of LDL when ingested in isolation of exercise, suggesting that in IGT the use of this antioxidant treatment does not ameliorate metabolic disturbances, but instead may detrimentally contribute to the pathogenesis of atherosclerosis and development of CVD. However, when α-lipoic acid is combined with exercise, this atherogenic effect is abolished.
To maintain normal cellular and physiological function, sufficient oxygen is required. Recently, evidence has suggested that hypoxia, either pathological or environmental, may influence bone health. It appears that bone cells are distinctly responsive to hypoxic stimuli; for better or worse, this is still yet to be elucidated. Hypoxia has been shown to offer potentially therapeutic effects for bone by inducing an osteogenic-angiogenic response, although, others have noted excessive osteoclastic bone resorption instead. Much evidence suggests that the hypoxic-inducible pathway is integral in mediating the changes in bone metabolism. Furthermore, many factors associated with hypoxia including changes in energy metabolism, acid-base balance and the increased generation of reactive oxygen species, are known to influence bone metabolism. This review aims to examine some of the putative mechanisms responsible for hypoxic-induced alterations of bone metabolism, with regard to osteoclasts and osteoblasts, both positive and negative.
Purpose To assess the dietary intake, nutrition knowledge and hydration status of Irish Gaelic footballers. Method One hundred and sixty-eight male club/county level Irish Gaelic footballers (median [IQR]; age 23 years [20.0, 27.0]; height 1.79 m [1.74, 1.84]; body mass 78.0 kg [73.5, 84.8]) participated in this cross-sectional study. Dietary intake was assessed using a 4-day semi-quantitative food record, with the application of Goldberg cut-offs to define acceptable reporters (n = 62). Nutrition knowledge was assessed using the validated Nutrition for Sport Knowledge Questionnaire in a sub-group of athletes (n = 24), while hydration status was measured using urine specific gravity pre-exercise (USG) in 142 athletes. Results Dietary analysis indicated an energy deficit at the group level (485 kcal [IQR 751,6]) (p < 0.001), with carbohydrate intakes (3.6 g/kg [IQR 3.0,4.1]) below current guidelines for athletes participating in one hour moderate intensity exercise per day (5–7 g/kg; p < 0.001). Average vitamin D (3.8 µg [IQR 1.8, 5.5]) and selenium intakes (54.2 µg [47.2, 76.7]) were significantly below the reference nutrient intakes (p < 0.001). A high proportion of individual athletes also had sub-optimal intakes for: vitamin D (95.2%), selenium (72.6%), vitamin A (38.7%), potassium (30.6%), zinc (25.8%), magnesium (19.4%) and calcium (12.9%). Nutrition knowledge was deemed poor (40.2 ± 12.4%), while pre-exercise hydration status (median USG 1.010 [IQR 1.005, 1.017]) was significantly below the cut-off to denote dehydration (1.020; p < 0.001). Conclusions Our findings suggest that Irish Gaelic footballers have sub-optimal dietary practices and lack nutrition knowledge. Individualised nutrition support may benefit these athletes to meet their nutrition requirements, to support health and performance.
The increased prevalence of CVD deaths in the past 60 years is a result in considerable part of the influence of environmental and lifestyle changes, including decreased daily energy expenditure through physical exertion. Physical activity prescription has therefore become an important public health issue. Exercise guidelines have evolved considerably since their first publication by the American College of Sports Medicine (ACSM) in 1978. Guidelines initially focused on moderate- to vigorous-intensity exercise to develop and maintain cardiorespiratory fitness. However, in the face of escalating physical inactivity, public health agencies sought to develop an exercise prescription more palatable to the sedentary majority and in 1995 recommended the accumulation of 30 min moderate-intensity exercise on most days of the week. The unexpected result of this message was that some individuals believed that vigorous exercise was not necessary, whilst others believed that low levels of physical activity were sufficient. In 2008 the ACSM and the American Heart Association sought to clarify this position and published an updated recommendation in which: the beneficial role of vigorous-intensity exercise is explicitly stated; adults are encouraged to combine moderate- and vigorous-intensity exercise to meet the minimum recommendation of moderate-intensity physical activity for a 30 min on 5 d/week or vigorous-intensity aerobic activity for 20 min on 3 d/week; the dose–response relationship between physical activity and health is reinforced. The immense challenge for public health professionals now lies in encouraging the sedentary population to adopt a more active lifestyle.
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