Study archive · page 30

Foods fortified with fibre modestly reduced body weight, fat mass, total and LDL cholesterol, triglycerides, fasting glucose and HbA1c across 31 randomised trials. Solid foods worked better than drinks, and fortification below 15 g per day showed more benefits than higher amounts.

⚠What it shows: Strong as nutrition evidence goes: results pooled from 31 trials where people were assigned at random. The fibre types and foods varied widely, and one author works in a major food company's research arm.Meta-analysis · Crit Rev Food Sci Nutr

Providing legumes (average 86 g a day) to 1,938 adults across 24 randomised trials lowered total cholesterol by 0.23 mmol/L, LDL cholesterol by 0.16 mmol/L and fasting glucose by 0.18 mmol/L. Not one eligible trial measured gut microbiome outcomes.

⚠What it shows: Worth taking seriously: moderate-certainty results pooled from 24 trials in 1,938 adults, some with existing conditions. The improvements were modest, and no trial was long enough or designed to test the gut microbiome effects legumes are famous for.Meta-analysis · Eur J Nutr

Viscous soluble fibre lowered systolic blood pressure by 1.59 mmHg and diastolic by 0.39 mmHg at a median dose of 8.7 g per day in pooled trials. Of five fibre types tested, only psyllium significantly reduced systolic pressure on its own, by 2.39 mmHg.

⚠What it shows: A real but small effect: results pooled from 22 trials in 1,430 people over a median of seven weeks. The studies disagreed with each other considerably, so the exact size of the drop is uncertain.Meta-analysis · Nutr Metab Cardiovasc Dis

A network meta-analysis of 116 trials in 4,711 adults doing resistance training found protein taken after exercise was most effective for gaining muscle mass, protein at night was most effective for strength, and milk proteins were among the best types; no timing or type improved physical performance tests.

⚠What it shows: Solid for muscle and strength, but the rankings come mostly from indirect comparisons because trials rarely pitted one timing against another directly. It pools 116 trials in 4,711 adults doing resistance training, and the evidence was rated moderate certainty.Meta-analysis · Int J Sport Nutr Exerc Metab

Pooling seven controlled trials in 541 adults, plant-based dietary patterns were associated with C-reactive protein concentrations 1.13 mg/L lower than omnivorous diets, though the trials varied widely and certainty in the result was rated low.

⚠What it shows: Promising but not proven: results pooled from just seven trials with 541 people, and the studies disagreed with each other enough that the authors rate the certainty as low. The effect held after stripping out trials that also prescribed exercise, which strengthens the case that diet was doing the work.Meta-analysis · Nutr Metab Cardiovasc Dis

In women with PCOS, an umbrella review of 28 meta-analyses found supplements including probiotics, curcumin, fish oil, inositol and vitamin D improved insulin and blood sugar markers with moderate to high certainty, while no diet alone showed high-certainty benefits.

⚠What it shows: About as strong as nutrition evidence gets: this sweeps 28 collections of pooled trial results in women with PCOS and grades how trustworthy each finding is. Even so, certainty varied a lot by outcome, and the diet-only findings rested on very low to low quality evidence.Systematic review · Nutr Rev

Pooled trial evidence found small but significant increases in bone mineral density at the femoral neck and lumbar spine in postmenopausal women doing high-intensity, impact or strength training; no significant effect appeared in premenopausal women.

⚠What it shows: Worth taking seriously but modest: results pooled from 8 trials totalling 379 women, and the bone gains were small. Only two of those trials included premenopausal women, so the lack of effect before menopause could simply reflect thin data.Study · Menopause

Across 31 randomised trials, combined exercise ranked as the most effective of five exercise types for improving sleep quality in perimenopausal and postmenopausal women, with flexibility exercise second; the best-ranked types also improved quality of life.

⚠What it shows: Encouraging but not the final word: results pooled from 31 trials in menopausal women, with certainty rated only low to moderate depending on exercise type. The rankings rely partly on indirect comparisons, since most trials never tested the exercise types against each other.Meta-analysis · Climacteric

A meta-analysis of 15 randomised trials in 1,110 middle-aged women found aerobic exercise significantly reduced waist circumference and blood glucose and significantly increased VO2 max.

⚠What it shows: Reasonably solid: results pooled from 15 trials with 1,110 middle-aged women taking part all pointed the same way on waist size, blood sugar and fitness. The abstract gives no figures for how large the changes were, and insulin and blood fats are not reported as improved.Meta-analysis · Health Care Women Int

A systematic review of 25 randomised trials found exercise and health education might help manage perimenopausal symptoms, but methodological inconsistencies mean evidence-based lifestyle guidelines remain out of reach. Notably, not a single trial exclusively tested a diet-based intervention.

⚠What it shows: Treat this as a map of the evidence rather than a verdict: a sweep of 25 randomised trials that varied so much in design and quality that firm conclusions were impossible. The clearest finding is the gap, since no study tested diet on its own.Systematic review · J Aging Phys Act

Across 29 randomised trials in middle-aged and older adults with sarcopenia, exercise dose showed an inverted U-shaped link with strength and mobility: handgrip strength gains were largest at 690 metabolic equivalent-minutes and functional mobility peaked at 830, so more was not better.

⚠What it shows: Reasonably solid, because it pools 29 trials where people were assigned at random, all in middle-aged and older adults with sarcopenia. The optimal doses come from statistical models rather than head to head tests, so treat the exact numbers as a guide, not a target.Review · Geriatr Nurs

A network meta-analysis of 34 randomised trials in 1746 middle-aged and older adults found moderate-intensity resistance training three times a week ranked highest for bone mineral density at most skeletal sites, while high-intensity training twice a week ranked best for total body density.

⚠What it shows: Fairly credible: results pooled from 34 trials in 1746 middle-aged and older adults, comparing training strategies across a network of studies. Many of the differences between strategies were not statistically significant, so the rankings point to a best bet rather than proving one.Meta-analysis · Calcif Tissue Int

Adding neuromuscular electrical stimulation on top of strength training in older adults with declining function improved only cardiorespiratory capacity beyond training alone, and the review behind this found just 3 eligible trials with low-quality evidence.

⚠What it shows: Treat this as an open question rather than an answer: a sweep of all the studies on this turned up just 3 trials worth pooling, and the authors themselves rated the evidence quality as low. The one benefit that did show, better cardiorespiratory capacity, needs confirming in bigger trials.Meta-analysis · Clinics (Sao Paulo)

Pooled results from six trials covering 76 healthy adults found molecular hydrogen supplementation did not significantly reduce exercise-induced oxidative stress compared with placebo, although it modestly improved antioxidant potential capacity, most clearly around intermittent exercise.

⚠What it shows: Take this seriously but lightly: results pooled from six small trials with just 76 people between them, using different doses, timings and delivery forms. The authors themselves call for more rigorous studies before anyone banks on the antioxidant bump.Systematic review · Front Nutr

A Cochrane review of nine trials in 622 overweight or obese adults found chromium picolinate produced an average extra weight loss of just 1.1 kg after 12 to 16 weeks, and the authors concluded there is no reliable evidence to support it as a slimming aid.

⚠What it shows: Treat this as a reason for scepticism: results pooled from nine trials in 622 overweight or obese adults showed only about a kilogram of extra loss, and the reviewers rated the evidence low quality. Safety reporting was so patchy that no firm conclusions could be drawn there either.Meta-analysis · Cochrane Database Syst Rev

Pooled results from six trials in 232 adults with musculoskeletal pain suggest transcranial alternating current stimulation modestly reduces pain compared with control, but shows no effect on sleep quality. The reviewers rated the overall certainty of the evidence as low.

⚠What it shows: An early signal at best: results pooled from just six trials totalling 232 people, and the reviewers rated their own certainty in the evidence as low for both outcomes. The pain benefit was modest, and sleep showed no change at all.Review · Complement Ther Med

In a systematic review of 39 randomised trials in adults with overweight or obesity, greater digital self-monitoring was linked to weight loss in 74% of the analyses that examined it, yet few interventions kept people tracking on at least 75% of days.

⚠What it shows: Convincing on consistency, weaker on cause: a sweep of 39 trials in adults with overweight or obesity found tracking and weight loss moving together, but it cannot prove the logging itself did the work. The real-world catch is that few programmes kept people tracking on most days.Systematic review · Obesity (Silver Spring)

Across 17 studies of military personnel, greater lean mass was generally associated with better strength, power, load carriage and cardiorespiratory performance, while higher body fat, BMI, visceral fat and waist circumference tracked with poorer performance; direct body composition measures were more informative than BMI alone.

⚠What it shows: A consistent picture rather than proof: a sweep of all the studies on this found 17 in military personnel, and they mostly report links rather than cause and effect. The studies disagreed with each other too much to pool the numbers, and few included women.Study · Mil Med

Across six randomised trials in 164 healthy older adults, exercise improved muscle mitochondrial quality, density, dynamics, oxidative capacity and antioxidant capacity. Resistance training was most tied to gains in mitochondrial density and dynamics, endurance training to antioxidant capacity.

⚠What it shows: An early signal rather than a settled answer: just six small trials covering 164 healthy older adults, and only one was rated good quality. The differences between training types need confirming before anyone builds a programme on them.Systematic review · Aging Clin Exp Res

In a network meta-analysis of 270 randomised trials with 15,827 participants, every exercise mode lowered resting blood pressure, but isometric training led the rankings with reductions of 8.24/4.00 mm Hg; the isometric wall squat and running were the most effective single exercises for systolic and diastolic pressure respectively.

⚠What it shows: About as strong as exercise evidence gets: results pooled from 270 trials covering 15,827 people, all with proper no-exercise control groups. The rankings compare modes across trials rather than head to head in the same study, so the ordering is a best estimate rather than a race everyone ran together.Meta-analysis · Br J Sports Med

Across 18 studies pooled in a meta-analysis, resistance training improved overall cognitive function in adults aged 60 and over, in both the cognitively healthy and the cognitively impaired; short-term memory improved only in the cognitively healthy.

⚠What it shows: Credible but imprecise: results pooled from 18 studies of adults aged 60 and over, covering both healthy and impaired cognition. The studies varied in the training used and in how thinking was tested, so the true size of the benefit is uncertain.Meta-analysis · Aging Ment Health

Probiotic supplements had a modest but statistically significant effect on symptoms of depression, anxiety and stress in healthy working adults across 12 randomised trials of 3,350 people, and were linked to lower cortisol. A marker of systemic inflammation did not change.

⚠What it shows: Promising but not settled: results pooled from 12 trials in 3,350 healthy employed adults found only a modest effect. The trials used different strains, doses and durations, so nobody yet knows which probiotics actually help.Meta-analysis · BMC Psychol

Across 12 pooled studies, people with midportion Achilles tendinopathy showed an immediate large reduction in tendon volume after isometric exercise, while healthy Achilles tendons kept their volume after acute loading.

⚠What it shows: Interesting but early: results pooled from 12 small studies of healthy and painful Achilles tendons, and several of the changes did not reach statistical significance. Whether a shrinking tendon means anything for pain or recovery is still unknown.Meta-analysis · J Biomech

In a meta-analysis of 62 studies, people with alcohol abuse or dependence showed moderate impairment across 11 of 12 cognitive domains in the first month of abstinence, deficits that persisted through the first year of sobriety and generally abated after 1 year.

⚠What it shows: Reassuring on recovery, but it compared different groups of people at different stages of sobriety rather than following the same individuals over time. It pools 62 studies of people with alcohol abuse or dependence, so it says little about moderate drinkers.Meta-analysis · Addict Biol