title: Whey protein with potassium bicarbonate supplement attenuates the reduction in muscle oxidative capacity during 19 days of bed rest.
abstract: The effectiveness of whey protein plus potassium bicarbonate-enriched diet (WP+KHCO3) in mitigating disuse-induced changes in muscle fiber oxidative capacity and capillarization was investigated in a 21-day crossover design bed rest study. Ten healthy men (31 ± 6 yr) once received WP+KHCO3and once received a standardized isocaloric diet. Muscle biopsies were taken 2 days before and during the 19th day of bed rest (BR) from the soleus (SOL) and vastus lateralis (VL) muscle. Whole-body aerobic power (V̇o2 max), muscle fatigue, and isometric strength of knee extensor and plantar flexor muscles were monitored. Muscle fiber types and capillaries were identified by immunohistochemistry. Fiber oxidative capacity was determined as the optical density (OD) at 660 nm of succinate dehydrogenase (SDH)-stained sections. The product of fiber cross-sectional area and SDH-OD (integrated SDH) indicated the maximal oxygen consumption of that fiber. The maximal oxygen consumption supported by a capillary was calculated as the integrated SDH in its supply area. BR reduced isometric strength of knee extensor muscles (P < 0.05), and the fiber oxidative capacity (P < 0.001) and V̇o2 max(P = 0.042), but had no significant impact on muscle capillarization or fatigue resistance of thigh muscles. The maximal oxygen consumption supported by a capillary was reduced by 24% in SOL and 16% in VL (P < 0.001). WP+KHCO3attenuated the disuse-induced reduction in fiber oxidative capacity in both muscles (P < 0.01). In conclusion, following 19 days of bed rest, the decrement in fiber oxidative capacity is proportionally larger than the loss of capillaries. WP+KHCO3appears to attenuate disuse-induced reductions in fiber oxidative capacity.
authors: Department of Medicine, Surgery and Health Sciences, University of Trieste, Cattinara Hospital, Trieste, Italy; School of Healthcare Science, Manchester Metropolitan University, Manchester, United Kingdom; bosutti@units.it.
authors: Alessandra
authors: A
authors: Bosutti
authors: Center for Space Medicine Berlin (ZWMB), Berlin, Germany.
authors: Michele
authors: M
authors: Salanova
authors: Center for Space Medicine Berlin (ZWMB), Berlin, Germany; Charité Universitätsmedizin Berlin, Vegetative Anatomy, Berlin, Germany.
authors: Dieter
authors: D
authors: Blottner
authors: University of Bonn, Department of Nutrition and Food Science, Bonn, Germany; Institute of Aerospace Medicine, German Aerospace Center DLR, Cologne, Germany; and.
authors: Judith
authors: J
authors: Buehlmeier
authors: Institute of Aerospace Medicine, German Aerospace Center DLR, Cologne, Germany; and.
authors: Edwin
authors: E
authors: Mulder
authors: Institute of Aerospace Medicine, German Aerospace Center DLR, Cologne, Germany; and.
authors: Jörn
authors: J
authors: Rittweger
authors: School of Healthcare Science, Manchester Metropolitan University, Manchester, United Kingdom.
authors: Moi Hoon
authors: MH
authors: Yap
authors: Institute of Aerospace Medicine, German Aerospace Center DLR, Cologne, Germany; and.
authors: Bergita
authors: B
authors: Ganse
authors: School of Healthcare Science, Manchester Metropolitan University, Manchester, United Kingdom; Institute of Sport Science and Innovations, Lithuanian Sports University, Kaunas, Lithuania.
authors: Hans
authors: H
authors: Degens
mesh_terms: D000284:Administration, Oral; D000328:Adult; D001510:Bed Rest / Q000009:adverse effects*; D001639:Bicarbonates / Q000008:administration & dosage*; D019587:Dietary Supplements; D006801:Humans; D008297:Male; D009133:Muscular Atrophy / Q000178:diet therapy* / Q000209:etiology / Q000503:physiopathology*; D010084:Oxidation-Reduction; D010101:Oxygen Consumption; D017680:Potassium Compounds / Q000008:administration & dosage*; D016896:Treatment Outcome; D000067816:Whey Proteins / Q000008:administration & dosage*
chemical_list: D001639:Bicarbonates; D017680:Potassium Compounds; D000067816:Whey Proteins; C026329:potassium bicarbonate
keywords: bed rest; capillarization; microgravity; muscle atrophy; oxidative capacity; whey protein