Apples, Berries for Muscle Health

HAMILTON, New Zealand & TOKYOFruits are known to pack a powerful punch, but some may also help support muscle strength and recovery themselves, according to two new studies published in Molecular Nutrition & Food Research.

In the first study, researchers from the New Zealand Institute for Plant and Food Research Ltd. examined whether blueberry polyphenolic extract could reduce the susceptibility of skeletal muscle cells to oxidative stress in vitro (2010;54(3):353-63. DOI:10.1002/mnfr.200900094). Muscle myotubes were simultaneously given polyphenol extracts (1 to 50 g/mL) and a range of oxidative stressors to assess oxidative damage. The blueberry fruit extract exerted a significant, dose-dependent protective effect. Further investigation into the anthocyanin sub-extracts and individual glycosides suggested malvidin galactoside and/or glucoside were the active compounds.

The second trial, conducted at Nippon Sport Science University, looked at whether apple polyphenols could protect against exercise-induced muscle strain injury in a controlled animal trial (2010;54(3):364-72. DOI: 10.1002/mnfr.200900145). Male Wistar rats received diets with or without 5 percent apple polyphenols for three weeks, and then were subjected to lengthening muscle contractions with electrical stimulation and forced ankle dorsiflexion over the course of one week before sacrifice. The muscles from the polyphenol group had significantly lower torque deficits and oxidative stress markers, and higher glutathione-S-transferase 1 mRNA levels. Researchers concluded dietary apple polyphenols could protect against muscle injury associated with lengthening contractions.