Nutritional advice

Objectives:
Is there a difference between high-load (≥70 of 1RM) and low-load (70 of 1RM) resistance training (RT) on femoral neck and lumbar spine bone mineral density (BMD) in middle-aged and older people?

Study design:
This review article included 6 RCTs.

Results and conclusions:
The investigators found the meta-analysis revealed no difference in femoral neck bone mineral density [MD = 0.00 g/cm², 95% CI = -0.01 to 0.01, p = 0.63, I2 = 47%, p = 0.07] and lumbar spine bone mineral density [MD = 0.01 g/cm², 95% CI = -0.00 to 0.02, p = 0.12, I2 = 59%, p = 0.02] between high-load (≥70 of 1RM) resistance training group and low-load (70 of 1RM) resistance training group. 

The investigators found subgroup analysis revealed a significant effect of high-load resistance training on femoral neck bone mineral density when participants presented normal bone mineral density values [MD = 0.01 g/cm², 95% CI = 0.00 to 0.02, p = 0.04] and on interventions lasting up to 6 months [MD = 0.01 g/cm², 95% CI = 0.00 to 0.02, p = 0.03].

The investigators concluded both high-load (≥70 of 1RM) and low-load (70 of 1RM) resistance training (RT) have similar effects on femoral neck and lumbar spine bone mineral density (BMD) in middle-aged and older people.

Original title:
High and Low-Load Resistance Training Produce Similar Effects on Bone Mineral Density of Middle-Aged and Older People: A Systematic Review With Meta-Analysis of Randomized Clinical Trials by Souza D, Barbalho M, […], Gentil P.

Link:
https://www.sciencedirect.com/science/article/abs/pii/S0531556520303211?via%3Dihub

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Objectives:
Nitric oxide related ergogenic aids such as arginine (Arg) have shown to impact positively on sport performance through several physiological and metabolic mechanisms. However, research results have shown to be controversial. Therefore, this review article has been conducted.

Do both acute and chronic arginine supplementation increase aerobic (≤VO2max) and anaerobic (>VO2max) performance?

Study design:
This review article included 15 RCTs with 386 males and 8 females.

Arginine supplementation was ingested by participants in both acute and chronic protocols.
Acute arginine protocol was 0.15 g/kg (≈10-11 g) ingested between 60-90 minutes before physical exercises.

Chronic arginine protocol was 1.5-2 g/day during 4-7 weeks or 10-12 g/day during 8 weeks.

Random effects model and pooled standardized mean differences (SMD) were used according to Hedges’ g.

Egger’s analyses did not find publication bias in anaerobic performance [z = 0.786, p = 0.432]. However, funnel plot showed publication bias in aerobic performance data [z = 2.873, p 0.05].

Results and conclusions:
The investigators found both acute and chronic arginine supplementation significantly improved anaerobic performance [SMD = 0.24, 95% CI = 0.05 to 0.43, p = 0.01, I2 = 0%, p = 0.85].

The investigators found both acute and chronic arginine supplementation significantly improved aerobic performance [SMD = 0.84, 95% CI = 0.12 to 1.56, p = 0.02, I2 = 89%, p 0.001].

The investigators concluded both acute and chronic arginine supplementation improve (anaerobic/aerobic) performance.

Original title:
Effects of Arginine Supplementation on Athletic Performance Based on Energy Metabolism: A Systematic Review and Meta-Analysis by Viribay A, Burgos J, […], Mielgo-Ayuso J.

Link:
https://www.mdpi.com/2072-6643/12/5/1300/htm

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Objectives:
Does protein supplementation yield beneficial effects on body composition and muscle function (strength and synthesis) in healthy adults, with an emphasis on the timing of protein intake?

Study design:
This review article included 65 RCTs with 2,907 participants (1,514 men and 1,380 women, 13 unknown sex). 26, 8 and 24 studies were used for meta-analysis on lean body mass, handgrip strength and leg press strength, respectively.

Results and conclusions:
The investigators found protein supplementation was effective in improving lean body mass (LBM) in adults [MD = 0.62 kg, 95% CI = 0.36 to 0.88] and older adults [MD = 0.46 kg, 95% CI = 0.23 to 0.70].
Sensitivity analyses removing studies without exercise training had no impact on the outcome.

The investigators found no association between protein supplementation and handgrip strength [older adults: MD = 0.26 kg, 95% CI = -0.51 to 1.04] and leg press strength [adults: MD = 5.80 kg, 95% CI = -0.33 to 11.93 and older adults: MD = 1.97 kg, 95% CI = -2.78 to 6.72].
Sensitivity analyses removing studies without exercise training had no impact on the outcome.

The investigators found data regarding muscle synthesis were scarce and inconclusive.

The investigators found subgroup analyses showed no beneficial effect of a specific timing of protein intake on lean body mass, handgrip strength and leg press strength.

The investigators concluded there is a positive impact of protein supplementation on lean body mass of healthy adults and older adults, independently of intake timing.

Original title:
The Role of Protein Intake and its Timing on Body Composition and Muscle Function in Healthy Adults: A Systematic Review and Meta-Analysis of Randomized Controlled Trials by Wirth J, Hillesheim E and Brennan L.

Link:
https://www.ncbi.nlm.nih.gov/pubmed/32232404

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The more lean body mass a person has, the higher their resting metabolic rate. Resting metabolic rate is the total number of calories burned when your body is completely at rest. Resting metabolic rate supports breathing, circulating blood, organ functions and basic neurological functions.

Objectives:
Which types of exercise training (whole body vibration training, aerobic training, strength training and combined training) increase lumbar spine and femoral neck bone mineral density (BMD) in older postmenopausal women (PMW)?

Study design:
This review article included 16 RCTs with 1,624 subjects.

Results and conclusions:
The investigators found no significant change in lumbar spine bone mineral density following exercise training [MD = 0.01 g/cm², 95% CI = -0.01 to 0.02].

The investigators found no significant change in femoral neck bone mineral density following exercise training [MD = 0.00 g/cm², 95% CI = -0.01 to 0.01].

The investigators found, however, subgroup analysis by type of exercise training revealed that lumbar spine bone mineral density [MD = 0.01, 95% CI = 0.00 to 0.02] raised significantly when whole-body vibration (WBV) was employed as intervention compared with RCTs that utilized aerobic [MD = -0.01, 95% CI = -0.02 to -0.01], resistance [MD = 0.01, 95% CI = -0.04 to 0.06] or combined training [MD = 0.03, 95% CI = -0.01 to 0.08].

The investigators found, on the other hand, lumbar spine bone mineral density [MD = - 0.01, 95% CI = -0.02 to -0.01] reduced significantly when aerobic exercise training was used as intervention compared with RCTs that utilized resistance training, combined training or whole-body vibration. 

The investigators concluded whole-body vibration is an effective method to improve lumbar spine bone mineral density in older postmenopausal women.

Original title:
The Impact of Different Modes of Exercise Training on Bone Mineral Density in Older Postmenopausal Women: A Systematic Review and Meta-analysis Research by Mohammad Rahimi GR, Smart NA, […], Mohammad Rahimi N.

Link:
https://www.ncbi.nlm.nih.gov/pubmed/32055889

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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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