Effects of pre- or post-exercise whey protein supplementation on oxidative stress and antioxidant enzymes in older women.
Study Goal
The researchers aimed to evaluate whether whey protein supplementation before or after resistance training affects oxidative stress and antioxidant enzyme activity in pre-conditioned older women.
Results Summary
All groups showed improvements in oxidative stress markers and antioxidant enzyme activity, with whey protein supplementation significantly reducing plasma uric acid levels compared to placebo, though no differences were observed based on timing of protein intake.
Population
Older women (≥60 years) who were already pre-conditioned.
Effective Dosage
35 g of whey protein or placebo pre- and post-training.
Duration
12 weeks.
Interactions
None mentioned.
| Intervention | Direction | Endpoint | Population | Dosage | Impact | Claim # |
|---|---|---|---|---|---|---|
whey protein supplementation | decrease | plasma uric acid concentration | pre-conditioned older women | - | reduces | #1 |
whey protein supplementation | no change | antioxidant enzyme activity | pre-conditioned older women | - | no further effect | #2 |
whey protein supplementation | no change | oxidative stress markers | pre-conditioned older women | - | no further effect | #3 |
resistance training program | increase | all oxidative stress markers | older women | - | improvements | #4 |
resistance training program | increase | antioxidant enzyme activity | older women | - | improvements | #5 |
whey protein supplementation pre-training (WP-PLA) | decrease | uric acid | older women | -8.3% | greater reductions | #6 |
whey protein supplementation post-training (PLA-WP) | decrease | uric acid | older women | -11.0% | greater reductions | #7 |
placebo-placebo (PLA-PLA) | decrease | uric acid | older women | -2.0% | reductions | #8 |
BACKGROUND: Oxidative stress is an imbalance between antioxidant system and production of free radicals and has been associated with the age-related deleterious changes. The defense system can be modulated by exercise and nutrition. OBJECTIVE: The purpose of this investigation was to evaluate the effect of whey protein supplementation pre- or post-resistance training on oxidative stress and antioxidant enzyme activity in pre-conditioned older women. METHODS: In a randomized, double-blind, and placebo-controlled design, 70 older women (≥60 years) were randomly assigned to one of the following three groups: whey protein-placebo (WP-PLA, n = 24), placebo-whey protein (PLA-WP, n = 23), and placebo-placebo (PLA-PLA, n = 23). Each group received 35 g of whey product or placebo pre- and post-training. The RT program was carried out over 12 weeks (3x/week; 3x 8-12 repetitions maximal). Oxidative stress and blood markers were assessed before and after intervention period. ANOVA for repeated measures was used for data analysis. RESULTS: There was a significant time effect (P < 0.05), with all groups showing improvements in all oxidative stress markers and antioxidant enzyme activity. A significant (P < 0.001) interaction time vs group was observed for uric acid, with both WP-PLA and PLA-WP presenting greater reductions compared with the PLA-PLA, without differences between the timing of protein intake (WP-PLA: -8.3%; PLA-WP: -11.0%; PLA-PLA:-2.0%). CONCLUSION: In already pre-conditioned older women, whey protein supplementation reduces plasma uric acid concentration with no further effect on antioxidant enzyme activity and oxidative stress markers. ClinicalTrials.gov: NCT03247192.