Chronic administration of apple polyphenols ameliorates hyperglycaemia in high-normal and borderline subjects: A randomised, placebo-controlled trial

• Published in: Diabetes research and clinical practice Vol. 129; pp. 43 - 51
• Main Authors: Shoji, Toshihiko, Yamada, Mitsuhiro, Miura, Tomisato, Nagashima, Kazuaki, Ogura, Kasane, Inagaki, Nobuya, Maeda-Yamamoto, Mari
• Format: Journal Article
• Language: English
• Published: Ireland Elsevier B.V 01.07.2017
• Subjects: Administration, Oral; Adult; Apple polyphenols; Blood Glucose; Dietary Supplements; Double-Blind Method; Endocrinology & Metabolism; Female; High-normal and borderline diabetes; Humans; Hyperglycemia - blood; Hyperglycemia - drug therapy; Hypoglycemic Agents - administration & dosage; Male; Malus - chemistry; Middle Aged; Oral glucose tolerance test; Plant Extracts - administration & dosage; Polyphenols - administration & dosage; Treatment Outcome; T2DM; Oral glucose tolerance test; ALP; LDL-C; OGTTTotal AUCglucose; DPP-4; ALT; IFG; LPS; HDL-C; LDH; Apple polyphenols; OGTT30-min glucose; PAI-1; HbA1c; BMI; γ-GTP; AST; GLP-1; IL-6; High-normal and borderline diabetes; AP; TC; CVD; HOMA-IR; TG; APC; TNF-α; IGT; OGTT 2-h glucose; NGT; FPG; OGTT; glucagon-like polypeptide-1; alanine aminotransferase; γ-glutamyl transpeptidase; total cholesterol; interleukin-6; the AUC of plasma glucose post-75 g oral glucose tolerance test; impaired fasting glycaemia; dipeptidyl peptidase-4; high-density lipoprotein cholesterol; alkaline phosphatase; tumour necrosis factor-alpha; homeostasis model assessment of insulin resistance; body mass index; lactate dehydrogenase; apple polyphenols; normal glucose tolerance; plasminogen activator inhibitor-1; 2-h post-75 g oral glucose tolerance test; apple procyanidins; fasting plasma glucose; lipopolysaccharide; 30 min post-75 g oral glucose tolerance test; triglyceride; oral glucose tolerance test; low-density lipoprotein cholesterol; impaired glucose tolerance; type 2 diabetes mellitus; haemoglobin A1c; OGTT 30-min glucose; OGTT Total AUCglucose; cardiovascular diseases; aspartate aminotransferase
• DOI: 10.1016/j.diabres.2017.03.028
• ISSN: 0168-8227; 1872-8227

•12weeks apple polyphenol administration were assessed on high-normal and borderline types in a double-blinded, placebo-controlled clinical trial.•Apple polyphenol ameliorated postprandial hyperglycaemia in high-normal and borderline types. We previously reported that apple polyphenols (AP) and their major active components, procyanidins, had beneficial effects on glucose homeostasis and diabetes in diabetic ob/ob mice. The present study was performed to evaluate the effects of chronic AP administration on glucose tolerance in high-normal and borderline human subjects. Subjects (n=65) with a fasting plasma glucose (FPG) level of 100–125mg/dL determined during a recent health check-up were randomised to receive tablets containing AP (600mg/day) or placebo tablets for 12weeks in a double-blinded, placebo-controlled clinical trial. The primary outcome was insulin resistance, assessed using a 75g oral glucose tolerance test (OGTT). The 12-week chronic administration of AP significantly reduced the increase in glucose at 30-min post-75g OGTT (OGTT30-min glucose) value, compared to the placebo regimen. Furthermore, in a subgroup of the high-normal (FPG value, 100–109mg/dL; 2-h post-75g OGTT glucose (OGTT2-h glucose) value, <140mg/dL) and borderline (FPG value, 110–125mg/dL; OGTT2-h glucose value, <140mg/dL and FPG value, <126mg/dL; OGTT2-h glucose value, 140–199mg/dL) subjects, OGTT30-min glucose value in the AP group (164.0±7.4mg/dL) was significantly lower than that of the placebo group (194.7±10.4mg/dL, p<0.05). No significant changes in the other lipid parameters and cytokine levels were observed. Chronic AP administration significantly improved impaired glucose tolerance in high-normal and borderline subjects. Larger and/or longer-term scale human studies are required to confirm the potential glucose homeostasis of AP.