Anne-Sophie Rousseau

Antioxidant Supplementation and Tapering Exercise Improve Exercise-Induced Antioxidant Response

Objective and Methods: The present controlled-training, double-blind study (supplemented, n = 7; placebo, n = 9) investigated whether taper training (TT) and antioxidant supplementation, i.e., 150 μg of selenium, 2000 IU of retinol, 120 mg of ascorbic acid and 30 IU of α-tocopherol, modulates antioxidant potential, redox status and oxidative damage occurrence both at rest and in response to exercise. Two weeks of TT followed four weeks of overloaded training. Dietary intakes were recorded. Before and after TT, triathletes did a duathlon consisting of 5-km run, 20-km bike and 5-km run. Biological studies were conducted at rest and after exercise. Results: Whatever the nutritional status, TT induced a decrease in resting blood reduced glutathione (GSH) concentration (p < 0.001), erythrocyte superoxide dismutase (SOD) activity (p < 0.0001) and plasma total antioxidant status (TAS) (p < 0.05). Only in the supplemented group (Su) with TT, did plasma glutathione peroxidase (GSH-Px) activity decrease (p < 0.05) and CD4+ cell concentration increase (p < 0.05). However, antioxidant supplementation increased plasma TAS increase in response to exercise and TT (p < 0.05). After exercise, TT also induced a lower decrease in blood reduced and oxidized (GSSG) glutathione (p < 0.01) in both groups, but TT had no effect on lipoperoxidation as estimated by plasma thiobarbituric reactive substances or on muscular damage occurrence estimated by plasma creatine kinase isoenzyme MB mass. Conclusion: During TT, antioxidant supplementation at nutritional doses reinforces antioxidant status response to exercise, with an effect on exercise-induced oxidative stress, and no effect on oxidative damage.

Antioxidant supplementation preserves antioxidant response in physical training and low antioxidant intake

The present controlled-training double-blind study (supplemented (S) group, n 7; placebo (P) group, n 10) was designed to investigate whether an antioxidant mixture (Se 150 microg, retinyl acetate mg, ascorbic acid 120 mg, alpha-tocopheryl succinate 20 mg) would allow overloaded triathletes to avoid adaptation failure in the antioxidant system [corrected]. Dietary intakes were recorded. The supplement of Se, and vitamins A and E provided 100 % of the French RDA. Four weeks of overloaded training (OT) followed 4 weeks of normal training (NT). After NT and OT, biological studies were conducted at rest and after a duathlon test (run 5 km, cycle 20 km, run 5 km). During the 4-week period of NT, blood levels of GSH levels increased in response to supplementation (P<0.05) and remained elevated during OT. Plasma glutathione peroxidase activity was significantly higher in the S group in all situations after NT and OT (P<0.01). The S group had increased erythrocyte Cu,Zn-superoxide dismutase activity in response to OT (P<0.05). Supplementation significantly reduced (P<0.05) the magnitude in duathlon-induced creatine kinase isoenzyme MB mass increase, which tended to be higher with OT (P=0.09). We conclude that the antioxidant mixture helped to preserve the antioxidant system during an OT-induced stress in subjects with initially low antioxidant intakes. Effects of supplementation during NT and/or OT are shown mostly by the alleviated muscle damage. The effects of the antioxidant mixture were observed for doses that can be provided by a diversified and well-balanced diet. The maintenance of normal nutritional status with regard to the antioxidant intake (Se, vitamins C and E) plays a key role in antioxidant adaptive effects during NT and OT.

Two non-consecutive 24 h recalls using EPIC-Soft software are sufficiently valid for comparing protein and potassium intake between five European centres – results from the European Food Consumption Validation (EFCOVAL) study

The use of two non-consecutive 24 h recalls using EPIC-Soft for standardised dietary monitoring in European countries has previously been proposed in the European Food Consumption Survey Method consortium. Whether this methodology is sufficiently valid to assess nutrient intake in a comparable way, among populations with different food patterns in Europe, is the subject of study in the European Food Consumption Validation consortium. The objective of the study was to compare the validity of usual protein and K intake estimated from two non-consecutive standardised 24 h recalls using EPIC-Soft between five selected centres in Europe. A total of 600 adults, aged 45-65 years, were recruited in Belgium, the Czech Republic, France, The Netherlands and Norway. From each participant, two 24 h recalls and two 24 h urines were collected. The mean and distribution of usual protein and K intake, as well as the ranking of intake, were compared with protein and K excretions within and between centres. Underestimation of protein (range 2-13%) and K (range 4-17%) intake was seen in all centres, except in the Czech Republic. We found a fair agreement between prevalences estimated based on the intake and excretion data at the lower end of the usual intake distribution (< 10% difference), but larger differences at other points. Protein and K intake was moderately correlated with excretion within the centres (ranges = 0·39-0·67 and 0·37-0·69, respectively). These were comparable across centres. In conclusion, two standardised 24 h recalls (EPIC-Soft) appear to be sufficiently valid for assessing and comparing the mean and distribution of protein and K intake across five centres in Europe as well as for ranking individuals.

Biomarker-based evaluation of two 24-h recalls for comparing usual fish, fruit and vegetable intakes across European centers in the EFCOVAL Study

Background/Objectives:A standardized methodology is important to enable consistent monitoring of dietary intake across European countries. For this reason, we evaluated the comparability of the assessment of usual food intake collected with two non-consecutive computerized 24-h dietary recalls (24-HDRs) and a food propensity questionnaire (FPQ) among five European centers.Subjects/Methods:Two 24-HDRs using EPIC-Soft (the software developed to conduct 24-HDRs in the European Prospective Investigation into Cancer and Nutrition (EPIC) Study) were performed to determine fish, fruit and vegetable (FV) consumed by 600 adults in Belgium (BE), the Czech Republic (CZ), France (FR), the Netherlands (NL) and Norway (NO) in a validation study. An FPQ was used to identify non-consumers. Information from the 24-HDRs and FPQ were used to estimate individual usual food intake by the Multiple Source Method (MSM). Blood samples were drawn to determine fatty acids in phospholipids and serum carotenoids as biomarkers of fish, and FV intake, respectively.Results:The pooled correlation between usual fish intake and eicosapentaenoic acid plus docosahexaenoic acid in phospholipids was 0.19 in men and 0.31 in women (P for heterogeneity >0.50) and center-specific correlations ranged between 0.08 (CZ) and 0.28 (BE and NO) in men, and between 0.19 (BE) and 0.55 (FR) in women. For usual FV intake, the pooled correlation with serum carotenoids was 0.31 in men and 0.40 in women (P for heterogeneity >0.10); the center-specific correlations varied between 0.07 (NO) and 0.52 (FR) in men, and between 0.25 (NL) and 0.45 (NO) in women.Conclusion:Two standardized 24-HDRs using EPIC-Soft and an FPQ appeared to be appropriate to rank individuals according to their fish and FV intake in a comparable way among five European centers.

Effects of Tai Chi Training on Antioxidant Capacity in Pre- and Postmenopausal Women

The risk of oxidative stress-related metabolic diseases increases with menopause and physical inactivity. We hypothesized that an 8-week Tai Chi (TC) training program (2 sessions in class; 2 sessions at home; 1-1:15/session) would improve antioxidant capacity and reduce cardiovascular risks in both pre- (n = 8) and postmenopausal (n = 7) sedentary women. Selected measures of physical fitness and blood parameters were analyzed before and after the program. Besides the well-known effects of TC on balance, flexibility, and maximum leg extensor strength, TC (1) increased erythrocyte glutathione peroxidase activity—an aerobic training-responsive antioxidant enzyme—and plasma total antioxidant status and (2) decreased plasma total homocysteine, a cardiovascular risk marker. In addition to being a low-velocity, low-impact, and relatively safe, TC is a suitable physical activity design for pre- and postmenopausal women to increase antioxidant defenses. Investigating breathing effects during TC movements would be an interesting area for further research in diseases prevention.

Antioxidant status in haemoglobin E carriers after acute and chronic strenuous exercises

Haemoglobin E (HbE), an unstable haemoglobin, is highly susceptible to oxidative damages. We examined how acute or chronic physiological challenge induced by exercise affects antioxidant response in HbE carriers. Two independent studies were conducted in individuals with HbE trait and paired normal Hb. In study 1, sedentary participants were tested in a graded maximal exercise and blood samples were collected before, immediately after, and 45 minutes after an acute exercise. Our data showed that erythrocyte glutathione peroxidase (GPx) activity failed to recover in HbE carriers after 45 minutes of rest. In study 2, athletes were trained in a 10-week strenuous training and blood samples were collected before and after training period. We found that athletes with HbE carriers showed a larger increase in plasma GPx activity compared to those with normal Hb. These data suggest that HbE carriers could cope with exercise-induced oxidative stress by adjusting endogenous antioxidant markers.