Study Title:

Hawthorn Lowers Diastolic Blood Pressure in Diabetics

Study Abstract

BACKGROUND: Hawthorn (Crataegus laevigata) leaves, flowers and berries are used by herbal practitioners in the UK to treat hypertension in conjunction with prescribed drugs. Small-scale human studies support this approach. AIM: To investigate the effects of hawthorn for hypertension in patients with type 2 diabetes taking prescribed drugs. DESIGN OF STUDY: Randomised controlled trial. SETTING: General practices in Reading, UK. METHOD: Patients with type 2 diabetes (n = 79) were randomised to daily 1200 mg hawthorn extract (n = 39) or placebo (n = 40) for 16 weeks. At baseline and outcome a wellbeing questionnaire was completed and blood pressure and fasting blood samples taken. A food frequency questionnaire estimated nutrient intake. RESULTS: Hypotensive drugs were used by 71% of the study population with a mean intake of 4.4 hypoglycaemic and/or hypotensive drugs. Fat intake was lower and sugar intake higher than recommendations, and low micronutrient intake was prevalent. There was a significant group difference in mean diastolic blood pressure reductions (P = 0.035): the hawthorn group showed greater reductions (baseline: 85.6 mmHg, 95% confidence interval [CI] = 83.3 to 87.8; outcome: 83.0 mmHg, 95% CI = 80.5 to 85.7) than the placebo group (baseline: 84.5 mmHg, 95% CI = 82 to 87; outcome: 85.0 mmHg, 95% CI = 82.2 to 87.8). There was no group difference in systolic blood pressure reduction from baseline (3.6 and 0.8 mmHg for hawthorn and placebo groups, respectively; P = 0.329). Although mean fat intake met current recommendations, mean sugar intake was higher and there were indications of potential multiple micronutrient deficiencies. No herb-drug interaction was found and minor health complaints were reduced from baseline in both groups. CONCLUSIONS: This is the first randomised controlled trial to demonstrate a hypotensive effect of hawthorn in patients with diabetes taking medication.

Study Information

Walker AF, Marakis G, Simpson E, Hope JL, Robinson PA, Hassanein M, Simpson HC.
Hypotensive effects of hawthorn for patients with diabetes taking prescription drugs: a randomised controlled trial.
Br J Gen Pract.
2006 June
Hugh Sinclair Unit of Human Nutrition, School of Food Biosciences, The University of Reading, Reading.

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