Metabolic and Cardiovascular Benefits of Apple and Apple-Derived Products: A Systematic Review and Meta-Analysis of Randomized Controlled Trials

Sun Jo Kim; Nguyen Hoang Anh; Cheol Woon Jung; Nguyen Phuoc Long; Seongoh Park; Young Hyun Cho; Young Cheol Yoon; Eun Goo Lee; Mina Kim; Eui Young Son; Tae Ha Kim; Yingqian Deng; Johan Lim; Sung Won Kwon

doi:10.3389/fnut.2022.766155

Metabolic and Cardiovascular Benefits of Apple and Apple-Derived Products: A Systematic Review and Meta-Analysis of Randomized Controlled Trials

Front Nutr. 2022 Apr 5:9:766155. doi: 10.3389/fnut.2022.766155. eCollection 2022.

Authors

Affiliations

¹ College of Pharmacy, Seoul National University, Seoul, South Korea.
² Research Institute of Pharmaceutical Sciences, Seoul National University, Seoul, South Korea.
³ Department of Statistics, Sungshin Women's University, Seoul, South Korea.
⁴ Department of Statistics, Seoul National University, Seoul, South Korea.
⁵ Plant Genomics and Breeding Institute, Seoul National University, Seoul, South Korea.

Abstract

Background: Quantitative evidence of the metabolic and cardiovascular effects of apples (Malus domestica) is lacking in interventional studies. This study aimed to summarize the available evidence of the beneficial effects of apples and apple-derived products (ADPs) on metabolic and cardiovascular markers.

Methods: Peer-reviewed randomized controlled trials (RCTs) were identified from four databases on May 3, 2021 and regularly updated until the end of May 2021. Demographic characteristics, intervention types, and evaluation parameters were extracted. A meta-analysis on the mean difference of change scores was conducted on commonly presented outcomes in the RCTs.

Results: The metabolic and cardiovascular effects of diverse regimens, including whole apple, apple extract, and apple juice, were examined in 18 eligible RCTs. Nine common evaluation outcomes were eventually introduced to the meta-analysis, including total cholesterol (TC), low-density lipoprotein (LDL), high-density lipoprotein (HDL), triglyceride, glucose, insulin, C-reactive protein, and systolic/diastolic blood pressures. The levels of TC (-2.69 mg/dL; 95% CI: -5.43, 0.04 mg/dL) and LDL (-2.80 mg/dL; 95% CI: -5.78, 0.17 mg/dL) showed a non-significant decreasing tendency after at least a week of apple consumption. Further subgroup analysis, particularly, a comparison with placebo as a control, showed a significant reduction in TC and LDL levels. When stratified by the baseline level, subjects with high TC and LDL level were shown to have more benefits from the apple intake. Intriguingly, apple and ADPs significantly reduced HDL levels to a small extent (-1.04 mg/dL; 95% CI: -1.79, -0.29 mg/dL). The other markers were mostly unaffected by the intervention.

Conclusion: Our investigation revealed that apples could improve blood cholesterol levels.

Systematic review registration: [https://www.crd.york.ac.uk/prospero/], identifier [CRD42020215977].

Keywords: apple pectin; apple polyphenol; blood marker; cardiovascular disease; lipid; metabolic syndrome; placebo-controlled study.

Publication types

Systematic Review