Turmeric improves post-prandial working memory in pre-diabetes independent of insulin

Asia Pac J Clin Nutr. 2014;23(4):581-91. doi: 10.6133/apjcn.2014.23.4.24.


Background and objectives: Cognitive impairment develops with pre-diabetes and dementia is a complication of diabetes. Natural products like turmeric and cinnamon may ameliorate the underlying pathogenesis.

Methods: People ≥ 60 years (n=48) with newly-recognised untreated pre-diabetes were randomised to a double-blind metabolic study of placebo, turmeric (1 g), cinnamon (2 g) or both (1 g & 2 g respectively), ingested at a white bread (119 g) breakfast. Observations were made over 6 hours for pre- and post-working memory (WM), glycaemic and insulin responses and biomarkers of Alzheimer's disease (AD)(0, 2, 4 and 6 hours): amyloid precursor protein (APP), γ-secretase subunits presenilin-1 (PS1), presenilin-2 (PS2), and glycogen synthase kinase (GSK-3β). Differences between natural product users and non-users were determined by Students t and chi square tests; and between pre-test and post-test WM by Wilcoxon signed rank tests. Interaction between turmeric and cinnamon was tested by 2-way ANOVA. Multivariable linear regression (MLR) took account of BMI, glycaemia, insulin and AD biomarkers in the WM responses to turmeric and cinnamon.

Results: No interaction between turmeric and cinnamon was detected. WM increased from 2.6 to 2.9 out of 3.0 (p=0.05) with turmeric, but was unchanged with cinnamon. WM improvement was inversely associated with insulin resistance (r=-0.418, p<0.01), but not with AD biomarkers. With MLR, the WM responses to turmeric were best predicted with an R2 of 34.5%; and with significant turmeric, BMI and insulin/glucose AUC beta-coefficients.

Conclusions: Co-ingestion of turmeric with white bread increases working memory independent of body fatness, glycaemia, insulin, or AD biomarkers.

背景:認知功能失調伴隨糖尿病前期與失智症是糖尿病的併發症之ㄧ。天然食品如薑黃及 肉桂可改善此致病機轉。本研究為評估薑黃肉桂如何影響糖尿病前期患者認知功能之代謝 研究。方法:對象為三軍總醫院參加老人健檢者,納入條件為其空腹血糖介於100-126 mg/dL,共計48 位參與者。經由雙盲性別分層隨機分派至服用口服降血糖藥物或其組合、 薑黃、肉桂或其組合及控制組共4 組,每組12 名,男女各半。參與者須於報到後抽取空 腹血液、實施工作記憶前測及測量基本體位資料。再於8 時服用早餐及受試藥物,各組分 別為安慰劑、薑黃1 克、肉桂2 克、肉桂2 克與薑黃1 克等。隨後每隔2 小時採集血液, 共4 次,於最後1 次抽血完畢後,再測工作記憶分數。利用RT-PCR 技術測得APP、 PS1、PS2、GSK-3βmRNA 表現量。利用t 檢定及卡方檢定比較天然食品使用者及非使用 者平均值之差異;魏克森符號等級檢定工作記憶前測及後測的分數。利用雙因子變異數分 析檢定薑黃與肉桂兩植物成分之交互作用。複迴歸模式分析校正身體質量指數、血糖、胰 島素濃度、阿茲海默症相關之生物標記後,薑黃肉桂對工作記憶之影響。結果:薑黃與肉 桂兩植物成分並無交互作用產生。有服用薑黃者工作記憶平均分數由2.6 增加至2.9 分, 為邊緣性顯著(p=0.05),服用肉桂者工作記憶前後測平均分數沒有顯著差異。工作記憶 分數之改善與胰島素阻抗呈負相關 (r=-0.418, p<0.01),但與阿茲海默症之相關生物標記 無顯著相關。複迴歸分析結果顯示服用薑黃、BMI 及胰島素阻抗為工作記憶分數最佳預測 因子。結論:本研究觀察到的薑黃改善認知效果,可能並非透過假設之降血糖途徑或降低 生物標記基因表現量而來,推測薑黃有其他保護神經元機制。

Publication types

  • Randomized Controlled Trial
  • Research Support, Non-U.S. Gov't

MeSH terms

  • Aged
  • Alzheimer Disease / blood
  • Biomarkers / blood
  • Blood Glucose / analysis
  • Body Mass Index
  • Bread
  • Cinnamomum zeylanicum
  • Curcuma*
  • Double-Blind Method
  • Female
  • Humans
  • Insulin / blood
  • Insulin Resistance
  • Male
  • Memory / drug effects*
  • Middle Aged
  • Phytotherapy*
  • Placebos
  • Plant Preparations / administration & dosage
  • Plant Preparations / therapeutic use*
  • Postprandial Period
  • Prediabetic State / blood
  • Prediabetic State / complications*


  • Biomarkers
  • Blood Glucose
  • Insulin
  • Placebos
  • Plant Preparations