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A Meta-Analysis of 46 Studies Identified by the FDA Demonstrates that Soy Protein Decreases Circulating LDL and Total Cholesterol Concentrations in Adults.
Blanco Mejia, S, Messina, M, Li, SS, Viguiliouk, E, Chiavaroli, L, Khan, TA, Srichaikul, K, Mirrahimi, A, Sievenpiper, JL, Kris-Etherton, P, et al
The Journal of nutrition. 2019;(6):968-981
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Abstract
BACKGROUND Certain plant foods (nuts and soy protein) and food components (viscous fibers and plant sterols) have been permitted by the FDA to carry a heart health claim based on their cholesterol-lowering ability. The FDA is currently considering revoking the heart health claim for soy protein due to a perceived lack of consistent LDL cholesterol reduction in randomized controlled trials. OBJECTIVE We performed a meta-analysis of the 46 controlled trials on which the FDA will base its decision to revoke the heart health claim for soy protein. METHODS We included the 46 trials on adult men and women, with baseline circulating LDL cholesterol concentrations ranging from 110 to 201 mg/dL, as identified by the FDA, that studied the effects of soy protein on LDL cholesterol and total cholesterol (TC) compared with non-soy protein. Two independent reviewers extracted relevant data. Data were pooled by the generic inverse variance method with a random effects model and expressed as mean differences with 95% CI. Heterogeneity was assessed and quantified. RESULTS Of the 46 trials identified by the FDA, 43 provided data for meta-analyses. Of these, 41 provided data for LDL cholesterol, and all 43 provided data for TC. Soy protein at a median dose of 25 g/d during a median follow-up of 6 wk decreased LDL cholesterol by 4.76 mg/dL (95% CI: -6.71, -2.80 mg/dL, P < 0.0001; I2 = 55%, P < 0.0001) and decreased TC by 6.41 mg/dL (95% CI: -9.30, -3.52 mg/dL, P < 0.0001; I2 = 74%, P < 0.0001) compared with non-soy protein controls. There was no dose-response effect or evidence of publication bias for either outcome. Inspection of the individual trial estimates indicated most trials (∼75%) showed a reduction in LDL cholesterol (range: -0.77 to -58.60 mg/dL), although only a minority of these were individually statistically significant. CONCLUSIONS Soy protein significantly reduced LDL cholesterol by approximately 3-4% in adults. Our data support the advice given to the general public internationally to increase plant protein intake. This trial was registered at clinicaltrials.gov as NCT03468127.
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Cumulative Meta-Analysis of the Soy Effect Over Time.
Jenkins, DJA, Blanco Mejia, S, Chiavaroli, L, Viguiliouk, E, Li, SS, Kendall, CWC, Vuksan, V, Sievenpiper, JL
Journal of the American Heart Association. 2019;(13):e012458
Abstract
Background Soy protein foods have attracted attention as useful plant protein foods with mild cholesterol-lowering effects that are suitable for inclusion in therapeutic diets. But on the basis of the lack of consistency in significant cholesterol reduction by soy in 46 randomized controlled trials, the US Food and Drug Administration (FDA) is reassessing whether the 1999 heart health claim for soy protein should be revoked. Methods and Results We have, therefore, performed a cumulative meta-analysis on the 46 soy trials identified by the FDA to determine if at any time, since the 1999 FDA final rule that established the soy heart health claim, the soy effect on serum cholesterol lost significance. The cumulative meta-analysis for both total cholesterol and low-density lipoprotein cholesterol demonstrated preservation of the small, but significant, reductions seen both before and during the subsequent 14 years since the health claim was originally approved. For low-density lipoprotein cholesterol, the mean reduction in 1999 was -6.3 mg/dL (95% CI, -8.7 to -3.9 mg/dL; P=0.00001) and remained in the range of -4.2 to -6.7 mg/dL ( P=0.0006 to P=0.0002, respectively) in the years after 1999. At no time point did the total cholesterol or low-density lipoprotein cholesterol reductions lose significance or were the differences at individual time points in the cumulative meta-analysis significantly different from those seen in 1999 when the health claim was approved. Conclusions A cumulative meta-analysis of the data selected by the FDA indicates continued significance of total cholesterol and low-density lipoprotein cholesterol reduction after soy consumption and supports the rationale behind the original soy FDA heart health claim.
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Effect of dietary pulse intake on established therapeutic lipid targets for cardiovascular risk reduction: a systematic review and meta-analysis of randomized controlled trials.
Ha, V, Sievenpiper, JL, de Souza, RJ, Jayalath, VH, Mirrahimi, A, Agarwal, A, Chiavaroli, L, Mejia, SB, Sacks, FM, Di Buono, M, et al
CMAJ : Canadian Medical Association journal = journal de l'Association medicale canadienne. 2014;(8):E252-62
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Abstract
BACKGROUND Evidence from controlled trials encourages the intake of dietary pulses (beans, chickpeas, lentils and peas) as a method of improving dyslipidemia, but heart health guidelines have stopped short of ascribing specific benefits to this type of intervention or have graded the beneficial evidence as low. We conducted a systematic review and meta-analysis of randomized controlled trials (RCTs) to assess the effect of dietary pulse intake on established therapeutic lipid targets for cardiovascular risk reduction. METHODS We searched electronic databases and bibliographies of selected trials for relevant articles published through Feb. 5, 2014. We included RCTs of at least 3 weeks' duration that compared a diet emphasizing dietary pulse intake with an isocaloric diet that did not include dietary pulses. The lipid targets investigated were low-density lipoprotein (LDL) cholesterol, apolipoprotein B and non-high-density lipoprotein (non-HDL) cholesterol. We pooled data using a random-effects model. RESULTS We identified 26 RCTs (n = 1037) that satisfied the inclusion criteria. Diets emphasizing dietary pulse intake at a median dose of 130 g/d (about 1 serving daily) significantly lowered LDL cholesterol levels compared with the control diets (mean difference -0.17 mmol/L, 95% confidence interval -0.25 to -0.09 mmol/L). Treatment effects on apolipoprotein B and non-HDL cholesterol were not observed. INTERPRETATION Our findings suggest that dietary pulse intake significantly reduces LDL cholesterol levels. Trials of longer duration and higher quality are needed to verify these results. TRIAL REGISTRATION ClinicalTrials.gov, no. NCT01594567.