The effect of brown rice compared to white rice on adiposity indices, lipid profile, and glycemic markers: a systematic review and meta-analysis of randomized controlled trials

Abstract

A few randomized controlled trials (RCTs) have assessed the effect of brown rice consumption on metabolic parameters compared to white rice, with inconsistent findings. Therefore, the present systematic review and meta-analysis was designed to evaluate the effect of brown rice on adiposity indices, lipid profile, and glycemic markers in adult subjects compared to white rice. In this study, PubMed/Medline, Scopus, Web of Sciences, and Embase databases were comprehensively searched until March 2021. Thirteen RCTs were selected and then included in the meta-analysis. As reported, brown rice significantly reduced weight by −1.63 kg (95% CI: −2.15 to −1.11, I²=97%, n = 6), body mass index (BMI) by −0.58 kg/m² (95% CI: −0.78 to −0.37, I²=96%, n = 6), and waist circumference by −2.56 cm (95% CI: −4.86 to −0.26, I²=88%, n = 5) compared with white rice. Moreover, it had no significant effect on lipid profile and glycemic markers. Besides, pre-germinated brown rice significantly declined weight (-1.75 kg, 95% CI: −2.70 to −0.81, I²=99%, n = 4), total cholesterol (-24.22 mg/dl, 95% CI: −33.03 to −15.41, I²=78%, n = 5), triglyceride (TG) (-43.28 mg/dl, 95% CI: −74.05 to −12.50, I²=90%, n = 5), low-density lipoprotein (LDL) (-20.05 mg/dl, 95% CI: −29.57 to −10.52, I²=71%, n = 5), and fasting blood glucose (FBG) (-15.83 mg/dl, 95% CI: −25.20 to −6.46, I²=91%, n = 5). In accordance with Grading of Recommendations Assessment, Development and Evaluation (GRADE) approach, the certainly of the included evidence was low and very low. The results of the present study indicate that, brown rice has anti-obesity effects in comparison with white rice; however, it has no beneficial effects on lipid profile and glycemic markers. Contrary to brown rice, it was shown that, pre-germinated brown rice significantly decreases body weight and improves lipid profile and FBG levels compared to white rice. Accordingly, our results indicate that, pre-germinated brown rice has better functional effects on promoting lipid profile and FBG compared to brown rice.

Keywords:

• Brown rice
• glycemia
• lipid profile
• meta-analysis
• obesity
• white rice

Acknowledgements

All authors have read and approved the final manuscript.

Disclosure statement

The authors declare there is no conflict of interest.

Abbreviation
CVD	=	cardiovascular disease
CHD	=	coronary heart disease
FBG	=	fasting blood glucose
GABA	=	γ-aminobutyric acid
GLP-1	=	glucagon-like peptide 1
GSIS	=	glucose-stimulated insulin secretion
HbA1c	=	glycated hemoglobin
GRADE	=	grading of recommendation sassessment, development and evaluation
HDL	=	high-density lipoprotein
HOMA-IR	=	homeostatic model assessment of insulin resistance
I2	=	I-squared
LDL	=	low-density lipoprotein
LDL-R	=	LDL receptors
MD	=	mean differences
PBF	=	percentage of body fat
PRISMA	=	the preferred reporting items for systematic reviews and meta-analyses
RCTs	=	randomized controlled trials
TC	=	total cholesterol
TG	=	triglyceride
VLDL	=	very low-density lipoprotein

Additional information

Funding

The authors reported no funding received for this study.