Nutritional considerations during prolonged exposure to a confined, hyperbaric, hyperoxic environment: Recommendations for saturation divers

Saturation diving is an occupation that involves prolonged exposure to a confined, hyperoxic, hyperbaric environment. The unique and extreme environment is thought to result in disruption to physiological and metabolic homeostasis, which may impact human health and performance. Appropriate nutritional intake has the potential to alleviate and/or support many of these physiological and metabolic concerns, whilst enhancing health and performance in saturation divers. Therefore, the purpose of this review is to identify the physiological and practical challenges of saturation diving and consequently provide evidence-based nutritional recommendations for saturation divers to promote health and performance within this challenging environment. Saturation diving has a high-energy demand, with an energy intake of between 44 and 52 kcal/kg body mass per day recommended, dependent on intensity and duration of underwater activity. The macronutrient composition of dietary intake is in accordance with the current Institute of Medicine guidelines at 45-65 % and 20-35 % of total energy intake for carbohydrate and fat intake, respectively. A minimum daily protein intake of 1.3 g/kg body mass is recommended to facilitate body composition maintenance. Macronutrient intake between individuals should, however, be dictated by personal preference to support the attainment of an energy balance. A varied diet high in fruit and vegetables is highly recommended for the provision of sufficient micronutrients to support physiological processes, such as vitamin B12 and folate intake to facilitate red blood cell production. Antioxidants, such as vitamin C and E, are also recommended to reduce oxidised molecules, e.g. free radicals, whilst selenium and zinc intake may be beneficial to reinforce endogenous antioxidant reserves. In addition, tailored hydration and carbohydrate fueling strategies for underwater work are also advised

A SOY-PROTEIN-BASED DIET DOES NOT ALTER SERUM MARKERS OF BONE FORMATION AND RESORPTION IN OVARIECTOMIZED, LOW-FIT RATS

Matthew W. Richard, Laura C. Ortinau, Terese Z. Zidon, Pamela S. Hinton and Victoria Viera-Potter. University of Missouri, Columbia, MO; e-mail: [email protected] Osteoporosis and the associated increased risk of fracture are serious health concerns for postmenopausal women. In addition to a significant decline in estrogen post-menopause, decreased physical activity may further predispose women to osteoporosis. The soy isoflavones genistein and daidzein are phytoestrogens, and, therefore, might reduce the negative effects of estrogen loss on bone. Low-capacity runner (LCR) rats are selectively bred for intrinsically low aerobic fitness and might serve as an effective model of menopause, following ovariectomy. Purpose: Therefore, the purpose of this study was to examine the effects of a soy-protein-based diet or a corn-based-diet on serum bone markers of formation and resorption in ovariectomized, low-capacity runner (LCR) rats. Methods: LCR rats were either ovariectomized or sham operated and fed a soy-protein-based diet (600 ppm genistein+daidzein; SOY) or a corn-gluten-meal-based protein diet (\u3c15 ppm genistein+daidzein; CORN) for 23 weeks. Bone formation (osteocalcin, OC; propeptide type I procollagen, P1NP) and resorption (tartrate-resistant acid phosphatase, TRAP5b; C-terminal telopeptide of type I collagen, CTx) serum markers in LCR rats were measured following ovariectomy (OVX) or sham (SHAM) surgery at 28 weeks of age. Results: Final body weight was significantly increased by OVX vs. SHAM (p=0.002), but not by diet. P1NP, OC, TRAP5b, and CTx were measured in plasma using ELISAs. A two-factor (OVX, diet) ANOVA was used to test for significant main and interactive effects. There was a trend for OC and CTx to be higher and TRAP5b lower in OVX vs. SHAM (main effects: p=0.098, p=0.083, and p=0.099, respectively). In OVX, P1NP/CTx was significantly less than SHAM (p=0.003). Conclusion: There were no effects of diet on serum bone markers. In conclusion, serum markers of bone formation and resorption are affected by OVX, but not by a soy-protein-based diet, in LCR rats

A comparative study of Brachychiton populneus seed and seed-fiber oils in Tunisia

We conducted a comparative study of two oils extracted from Brachychiton populneus seeds and seed fibers grown in Tunisia. Oil yields from seed and seed fiber were 29.95 and 5.30%, respectively. GC-MS analysis showed that the most abundant fatty acid was linoleic acid (37.91%) followed by oleic acid (30.67%) in seeds. In seed fiber, the most abundant were oleic acid (62.04%) and linoleic acid (11.90%). Sterculic acid (7.27%), a rare fatty acid, was detected in seed oil. Moreover, carotenoid and chlorophyll levels were approximately two-fold higher in seed-fiber oil (39.66 and 1.9 mg/kg) than in seed oil (19.48 and 0.78 mg/kg). Tocol contents were more than 10-fold higher in fiber-seed oil (979.31 mg/100 g) than in seed oil (83.2 mg/100 g). Furthermore, thermal behavior (TGA and DSC) in both oils, and the antioxidant activity, phenolic content, and oxidative stability at different temperatures in seed oil were evaluated. The results of this study suggest that B. populneus seed oil may have an important role in non-food applications and that seed-fiber oil is a source of high-value compounds