Nutrition and health

Objectives:
Epidemiological evidences regarding the association between physical activity and the risk of lung cancer are still controversial. Therefore, this review article has been conducted.

Does physical activity reduce risk of lung cancer?

Study design:
This review article included 20 cohort studies with a total of 2,965,811 participants and 31,807 lung cancer cases.

The study population were adults with age of >18 years.
Most studies were adjusted for major confounders including age, sex, smoking status and body mass index, etc.

The quality scores ranged from 5 to 9 with a median score of 8.
3 studies were evaluated with a score of 7 and others with a score of ≥7. Thus, the majority of the studies included in the meta-analysis were assessed as high-quality studies.

There might be little indication of publication bias in this meta-analysis.

Results and conclusions:
The investigators found compared with the low level of physical activity, the high level of physical activity significantly reduced risk of lung cancer with 17% [pooled RR = 0.83, 95% CI = 0.77 to 0.90, I2 = 62.6%, p heterogeneity 0.001].

The investigators found in subgroup analyses, compared with the low level of physical activity, the high level of physical activity significantly reduced risk of lung cancer among women with 10% [pooled RR = 0.90, 95% CI = 0.82 to 0.99].

The investigators found in subgroup analyses compared with the low level of physical activity, the high level of physical activity significantly reduced risk of lung cancer among men with 19% [pooled RR = 0.81, 95% CI = 0.73 to 0.90].

The investigators found smokers with a high level of physical activity were associated with a 10% lower risk for lung cancer [RR = 0.90, 95% CI = 0.84 to 0.97], while the association was not significant among non-smokers [RR = 0.95, 95% CI = 0.88 to 1.03].

Subgroups analysis stratified by whether the studies adjusted for smoking intensity and durations yielded the same magnitude of RR.

However, the RR for subgroups without adjustment for dietary factors was 0.74 [95% CI = 0.71 to 0.77], which was significantly lower than that with dietary factors adjusted [RR = 0.89, 95% CI = 0.84 to 0.95].

The investigators found in sensitivity analyses, the pooled RRs ranged from 0.82 [95% CI = 0.76 to 0.89] to 0.86 [95% CI = 0.81 to 0.92]. The trend was generally similar with the overall analysis.

The investigators concluded a high level of physical activity reduces risk of lung cancer among smokers. Large interventional studies are expected to further verify these findings. If the inverse association, as well as the effect modification by smoking status, reflects a causal relation, future precision prevention of lung cancer by increased physical activity may be more effective when targeting to smokers rather than non-smokers.

Original title:
Association Between Physical Activity and Lower Risk of Lung Cancer: A Meta-Analysis of Cohort Studies by Liu Y, Li Y, […], Fan XX.

Link:
https://www.ncbi.nlm.nih.gov/pmc/articles/PMC6349707/

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Objectives:
Taurine is central to many physiological processes, some of which are augmented by exogenous supply and have the potential to facilitate endurance performance; however, its independent effects on performance have not been systematically analyzed. Therefore, this review article has been conducted.

Does supplementation of taurine improve human endurance performance?

Study design:
This review article included 10 peer-reviewed articles. A sub-analysis of time-to-exhaustion (TTE) trials (n = 7) was also performed.

The doses of taurine ranged from 1 to 6 g/day and were provided in single doses and for up to 2 weeks among a range of subjects.

Results and conclusions:
The investigators found that taurine supplementation significantly improved overall endurance performance [Hedges' g = 0.40, 95% CI = 0.12-0.67, p = 0.004], which was similar in TTE trials [Hedges' g = 0.43, 95% CI = 0.12-0.75, p = 0.007].

The investigators found no differences between acute or chronic supplementation for the full sample [p = 0.897] or the TTE group [p = 0.896].

The investigators found that the dose of taurine did not moderate its effect on endurance performance [p > 0.05].

The investigators concluded that human endurance performance can be improved by orally ingesting a single dose of taurine in varying amounts (1-6 g).

Original title:
The Effects of an Oral Taurine Dose and Supplementation Period on Endurance Exercise Performance in Humans: A Meta-Analysis by Waldron M, Patterson SD, […], Jeffries O.

Link:
https://www.ncbi.nlm.nih.gov/pubmed/29546641

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Objectives:
Older adults experience age-related physiological changes that affect body weight and body composition. In general, nutrition and exercise have been identified as potent stimulators of protein synthesis in skeletal muscle. Milk proteins are excellent sources of all the essential amino acids and may represent an ideal protein source to promote muscle anabolism in older adults undergoing resistance training. However, several randomized control trials (RCTs) have yielded mixed results on the effects of milk proteins supplementation in combination with resistance training on body weight and composition. Therefore, this review article has been conducted.

Does supplementation of milk protein alone or in combination with resistance training, increase fat-free mass in older adults (age ≥ 60 years)?

Study design:
This review article included 10 RCTs involving 574 participants (mean age range from 60 to 80.8 years).

There was no statistical evidence of publication bias among the studies.

Results and conclusions:
The investigators found overall, the combination of milk proteins supplementation and resistance training had no significant effect on fat mass [0.30, 95% CI = -0.25 to 0.86 kg] or body weight [1.02, 95% CI = -0.01 to 2.04 kg].

The investigators found, however, a positive effect of milk proteins supplementation paired with resistance training on fat-free mass [0.74, 95% CI = 0.30 to 1.17 kg].

The investigators found greater fat-free mass gains were observed in studies that included more than 55 participants [0.73, 95% CI = 0.30 to 1.16 kg] and in studies that enrolled participants with aging-related medical conditions [1.60, 95% CI = 0.92 to 2.28 kg].

The investigators concluded supplementation of milk protein, in combination with resistance training, is effective to elicit fat-free mass gain in older adults (age ≥ 60 years).

Original title:
Effects of Milk Proteins Supplementation in Older Adults Undergoing Resistance Training: A Meta-Analysis of Randomized Control Trials by Hidayat K, Chen GC, […], Qin LQ.

Link:
https://www.ncbi.nlm.nih.gov/pubmed/29380851

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Objectives:
Individuals with mild cognitive impairment (MCI) are at high risk for developing dementia. Physical exercise is a promising intervention for cognitive decline. Systematic reviews regarding the effects of physical exercise on cognitive and psychological outcomes among MCI patients are limited and a systematic review exploring the effects of exercise modalities on the results has not been conducted. Therefore, this review article has been conducted.

Do individuals with mild cognitive impairment benefit from physical exercise?

Study design:
This review article included 11 studies. The exercise interventions can be classified into 3 types: (a) aerobic exercise, (b) resistance exercise and (c) multi-modal exercise.

Results and conclusions:
The investigators found that physical exercise had beneficial effects for global cognition [SMD = 0.30, 95% CI = 0.10-0.49, p = 0.002].

The investigators found subgroup analysis demonstrated that aerobic exercise programmes were consistently associated with medium effect size [SMD = 0.54-0.58].

The investigators found, however, the effects of physical exercise on domain-specific cognitive function and psychological outcomes in mild cognitive impairment patients remained inconclusive.

The investigators found sensitivity analysis showed that types of control exerted influence on the outcomes.

The investigators concluded that physical exercise, aerobic exercise in particular, benefits global cognition in mild cognitive impairment patients. The evidence of physical exercise on domain-specific cognitive function and psychological outcomes remains unclear, more trials with rigorous study design are necessary to provide the evidence.

Original title:
The effectiveness of physical exercise on cognitive and psychological outcomes in individuals with mild cognitive impairment: A systematic review and meta-analysis by Song D, Yu DSF, […], Lei Y.

Link:
https://www.ncbi.nlm.nih.gov/pubmed/29334638

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Objectives:
Does dietary protein supplementation augment resistance exercise training (RET)-induced gains in muscle mass and strength?

Study design:
This review article included 49 RCTs with RET ≥6 weeks in duration, involving 1,863 participants.

Results and conclusions:
The investigators found that during periods of prolonged RET, dietary protein supplementation significantly increased changes in:
-strength-one-repetition-maximum [2.49 kg, 95% CI = 0.64 to 4.33];
-FFM (fat free mass) [0.30 kg, 95 BI = 0.09 to 0.52];
-muscle size-muscle fibre cross-sectional area [CSA = 310 µm², 95% CI = 51 to 570] and
-mid-femur [CSA = 7.2 mm², 95% CI = 0.20 to 14.30]

The investigators found that the impact of protein supplementation on gains in fat free mass (FFM) was reduced with increasing age [-0.01 kg, 95% CI = -0.02 to -0.00, p = 0.002] and was more effective in resistance-trained individuals [0.75 kg, 95% CI = 0.09 to 1.40, p = 0.03].

The investigators found that protein supplementation beyond total protein intakes of 1.62 g/kg/day resulted in no further RET-induced gains in fat free mass.

The investigators concluded dietary protein supplementation (1.62 g/kg/day) enhances changes in muscle strength and size during prolonged resistance exercise training in healthy adults.

Original title:
A systematic review, meta-analysis and meta-regression of the effect of protein supplementation on resistance training-induced gains in muscle mass and strength in healthy adults by Morton RW, Murphy KT, […], Phillips SM.

Link:
https://www.ncbi.nlm.nih.gov/pubmed/28698222

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Objectives:
Does resistance training reduce blood pressure in prehypertensive and hypertensive subjects?

Study design:
This review article included 5 RCTs provided data on 201 individuals.

Results and conclusions:
The investigators found when compared to group control, resistance training alone significantly reduced systolic blood pressure with 8.2 mmHg in prehypertensive and hypertensive subjects [95% CI = -10.9 to -5.5, I2 = 22.5%, p for heterogeneity = 0.271 and effect size = -0.97].

The investigators found when compared to group control, resistance training alone significantly reduced diastolic blood pressure with 4.1 mmHg in prehypertensive and hypertensive subjects [95% CI = -6.3 to -1.9, I2 = 46.5%, p for heterogeneity = 0.113 and effect size = -0.60].

The investigators concluded resistance training alone reduces systolic and diastolic blood pressure in prehypertensive and hypertensive subjects. These findings support the recommendation of resistance training as a tool for management of systemic hypertension.

Original title:
Resistance training alone reduces systolic and diastolic blood pressure in prehypertensive and hypertensive individuals: meta-analysis by de Sousa EC, Abrahin O, […], Vieira RP.

Link:
https://www.ncbi.nlm.nih.gov/pubmed/28769100

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Objectives:
Although pre-exercise consumption of a low-glycemic-index (LGI) carbohydrate meal is generally recommended, the findings regarding subsequent exercise performance are inconsistent. Therefore, this review article (meta-analysis) has been conducted.

Does a pre-exercise low-glycemic-index carbohydrate meal lead to greater endurance performance than a pre-exercise high-glycemic-index (HGI) meal?

Study design:
This review article included 15 trials (randomized controlled or crossover trials).
All included studies were of low research quality.

Results and conclusions:
The investigators found the synthesized effect size [d  = 0.42, z  = 3.40, p  = 0.001] indicated that the endurance performance following a low-glycemic-index carbohydrate meal was superior to that following a high-glycemic-index meal.

The investigators found subgroup analyses demonstrated that the treatment effect did not vary across outcome measures (exercise to exhaustion, time trial and work output) or athletic status (trained or recreational participants).

The investigators concluded weak evidence supports the claim that endurance performance following pre-exercise consumption of a low-glycemic-index (LGI) carbohydrate meal is superior to that following pre-exercise consumption of a high-glycemic-index (HGI) meal. Further high-quality research in this area is warranted.

Original title:
Effect of pre-exercise carbohydrate diets with high vs low glycemic index on exercise performance: a meta-analysis by Heung-Sang Wong S, Sun FH, […], Ya-Jun Huang W.

Link:
https://www.ncbi.nlm.nih.gov/pubmed/28383695

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A low-glycemic-index (LGI) carbohydrate diet is a diet with a lot of products with GI lower than 55. Products with GI lower than 55 are called low-glycemic-index carbohydrate products. These products are low-glycemic-index carbohydrate products.
 

Objectives:
It has been suggested that prenatal exposure to n-3 long-chain fatty acids protects against asthma and other allergy-related diseases later in childhood. The extent to which fish intake in pregnancy protects against child asthma and rhinitis symptoms remains unclear. Therefore, this review article (meta-analysis) has been conducted.

Does fish consumption during pregnancy reduce risk of asthma and other allergy-related diseases later in childhood?

Study design:
This review article included data from 60,774 mother-child pairs participating in 18 European and US birth cohort studies.
Information on wheeze, asthma and allergic rhinitis prevalence was collected using validated questionnaires.
The time periods of interest were: infancy (0-2 years), preschool age (3-4 years) and school age (5-8 years).
The median fish consumption during pregnancy ranged from 0.44 times/week in The Netherlands to 4.46 times/week in Spain.

Results and conclusions:
The investigators found maternal fish intake during pregnancy was not associated with offspring wheeze symptoms in any age group nor with the risk of child asthma [adjusted meta-analysis relative risk per 1-time/week = 1.01, 95% CI = 0.97-1.05] and allergic rhinitis at school age [RR = 1.01, 95% CI = 0.99-1.03].

These results were consistently found in further analyses by type of fish and seafood consumption and in sensitivity analyses.

The investigators concluded maternal fish intake during pregnancy is not associated with offspring wheeze symptoms in any age group (0-2 years, 3-4 years and 5-8 years) or with the risk of child asthma and allergic rhinitis at school age (5-8 years).

Original title:
Fish and seafood consumption during pregnancy and the risk of asthma and allergic rhinitis in childhood: a pooled analysis of 18 European and US birth cohorts by Stratakis N, Roumeliotaki T, […], Chatzi L.

Link:
https://www.ncbi.nlm.nih.gov/pubmed/28338907

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Objectives:
Does polyphenol supplementation increase sport performance?

Study design:
This review article included 14 studies. Of these, the studied populations were predominately-trained males with an average intervention dose of 688 ± 478mg polyphenols per day.

Results and conclusions:
The investigators found pooled results demonstrated polyphenol supplementation for at least 7 days significantly increased performance by 1.90% [95% CI = 0.40-3.39].

The investigators found sub-analysis of 7 studies using quercetin significantly increased performance by 2.82% [95% CI = 2.05-3.58].

The investigators found no adverse effects reporting in studies in relation to the intervention.

The investigators concluded daily 688mg polyphenol supplementation, preferably quercetin supplementation for at least 7 days increases performance in healthy individuals.

Original title:
Polyphenols and Performance: A Systematic Review and Meta-Analysis by Somerville V, Bringans C and Braakhuis A.

Link:
https://www.ncbi.nlm.nih.gov/pubmed/28097488

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