Effects of supplementation with milk protein on glycemic parameters: a GRADE-assessed systematic review and dose–response meta-analysis

• Published in: Nutrition journal Vol. 22; no. 1; pp. 1 - 49
• Main Authors: Mohammadi, Shooka, Asbaghi, Omid, Dolatshahi, Sina, Omran, Hossein Salehi, Amirani, Niusha, Koozehkanani, Fatemeh Jahangir, Garmjani, Hossein Bagherzadeh, Goudarzi, Kian, Ashtary-Larky, Damoon
• Format: Journal Article
• Language: English
• Published: London BioMed Central Ltd 06-10-2023; BioMed Central; BMC
• Subjects: Amino acids; Analysis; Bias; Blood sugar; Body mass index; Casein protein; Citation management software; Clinical trials; Control; Dairy products; Diabetes; Diabetes therapy; Diet therapy; Dietary supplements; Fasting; Glucose; Glycemic indices; Glycosylated hemoglobin; Health aspects; Hemoglobin; High blood glucose (HBG); Homeostasis; Hyperglycemia; Insulin resistance; Laboratory testing; Lactose; Meta-analysis; Milk; Milk protein; Milk proteins; Observational studies; Online databases; Physiological aspects; Political aspects; Prevention; Proteins; Review; Serum levels; Supplements; Systematic review; Type 2 diabetes; Whey protein; Iran
• ISSN: 1475-2891; 1475-2891
• DOI: 10.1186/s12937-023-00878-1

It is suggested that supplementation with milk protein (MP) has the potential to ameliorate the glycemic profile; however, the exact impact and certainty of the findings have yet to be evaluated. This systematic review and dose-response meta-analysis of randomized controlled trials (RCTs) assessed the impact of MP supplementation on the glycemic parameters in adults. A systematic search was carried out among online databases to determine eligible RCTs published up to November 2022. A random-effects model was performed for the meta-analysis. A total of 36 RCTs with 1851 participants were included in the pooled analysis. It was displayed that supplementation with MP effectively reduced levels of fasting blood glucose (FBG) (weighted mean difference (WMD): -1.83 mg/dL, 95% CI: -3.28, -0.38; P = 0.013), fasting insulin (WMD: -1.06 uU/mL, 95% CI: -1.76, -0.36; P = 0.003), and homeostasis model assessment of insulin resistance (HOMA-IR) (WMD: -0.27, 95% CI: -0.40, -0.14; P < 0.001) while making no remarkable changes in serum hemoglobin A1c (HbA1c) values (WMD: 0.01%, 95% CI: -0.14, 0.16; P = 0.891). However, there was a significant decline in serum levels of HbA1c among participants with normal baseline body mass index (BMI) based on sub-group analyses. In addition, HOMA-IR values were significantly lower in the MP supplement-treated group than their untreated counterparts in short- and long-term supplementation ([less than or equal to] 8 and > 8 weeks) with high or moderate doses ([greater than or equal to] 60 or 30-60 g/d) of MP or whey protein (WP). Serum FBG levels were considerably reduced upon short-term administration of a low daily dose of WP (< 30 g). Furthermore, the levels of serum fasting insulin were remarkably decreased during long-term supplementation with high or moderate daily doses of WP. The findings of this study suggest that supplementation with MP may improve glycemic control in adults by reducing the values of fasting insulin, FBG, and HOMA-IR. Additional trials with longer durations are required to confirm these findings.