Double-Blind, Randomized, Cross-Over Trial of Aged Garlic Extract for Hypertension

Double-Blind, Randomized, Cross-Over Trial of Aged Garlic Extract for Hypertension

The primary objective of this trial is to assess the effect of consumption of aged garlic extract powder on 24 h systolic and diastolic ambulatory blood pressure in hypertensive individuals following 8 weeks of supplementation.

Additional secondary objectives are to assess the effects of aged garlic extract powder intake for 8 weeks on lipid profile (TC, HDL-C, LDL-C, and TG concentrations), blood glucose, office blood pressure, pulse-wave velocity and augmentation index, body mass index, and waist and hip circumference.

Forty hypertensive volunteers between 18 and 75 years will be recruited from the Winnipeg (Manitoba, Canada) area to participate in a two arm crossover, double-blind, randomized, placebo-controlled intervention study for 8 weeks per study period following obtainment of informed consent.

The 2 periods of treatment will include:

1. Treatment period: One capsule twice a day, providing 600 mg each of aged garlic extract powder, for a total of 1200 mg/day of aged garlic extract powder.
2. Control period: The control product will be an identical-looking placebo capsules containing cellulose, which is being used as a filler in the treatment capsules.

Inclusion Criteria:

• Ability to give written informed consent.
• Age: greater than or equal to 40 and less than or equal to 70 years.
• Systolic blood pressure140-160mmHg and/or diastolic blood pressure 90-100 mmHg
• LDL-C less than or equal to 4.9mmol/L
• Those on a stable dose of blood pressure lowering or lipid-lowering medication for greater than or equal to 3 months; if a participant chooses to stop taking blood pressure lowering medications, they will be required to have a minimum 3 month washout period prior to commencement of the study; all other medications medications will be permitted if they are on a stable dose before the start of the study
• Gender: Male and women who are not pregnant (determined by a negative urine pregnancy test at screening for women of childbearing potential) or lactating.
• Language: Participants must be able to read, write and speak English.

Exclusion Criteria:

• Systolic blood pressure > 160mmHg and/or diastolic blood pressure >100mmHg
• Those currently taking (or have taken within the last 3 months) lipid-lowering or blood pressure-lowering supplements (i.e., omega-3 supplements, plant sterols/stanols foods and/or supplements, fibre, etc.)
• Patients with unstable or serious illness, for example, dementia, terminal illness, recent bereavement, secondary hypertension, recent significant medical diagnosis.
• History of cancer, chronic illness, cardiovascular problems, liver and kidney disease (including chronic kidney disease (GFR < 60ml/min/1.732)), diabetes, inflammatory bowel disease, pancreatitis, gallbladder or biliary disease, neurological/psychological disease, bleeding disorders, experienced platelet abnormalities, macrovascular target organ damage (including cerebrovascular disease, stroke, hypertensive retinopathy, left ventricular dysfunction, angina pectoris, myocardial infarction, and peripheral artery disease)
• History of taking any type of garlic preparation (i.e., dried garlic homogenate, aged garlic extract, processed garlic capsule, time-released garlic powder tablet, regular garlic pill, garlic powder and garlic oil) in the past 6 months. in the past 3 months. (Note: regular garlic clove consumption as part of prepared meals, cooking preparations, etc. are permitted throughout the study period)
• Plan to consume any type of garlic preparation (i.e., dried garlic homogenate, aged garlic extract, processed garlic capsule, time-released garlic powder tablet, regular garlic pill, garlic powder and garlic oil. at any time during the study. (Note: regular garlic clove consumption as part of prepared meals, cooking preparations, etc. are permitted throughout the study period)
• Have gained or lost greater than or equal to 10lbs in the previous 3 months, or plan to lose weight at any time during the study
• Plan to become pregnant during the study period.
• Women of childbearing potential not using effective contraception which include: Hormonal contraceptives including combined oral contraceptives, hormone birth control patch, vaginal contraceptive ring, injectable contraceptives, or hormonal implants; Intrauterine devices (IUD) or Intrauterine system (IUS); Tubal ligation; Vasectomy of partner; Double barrier method (use of physical barrier by both partners, e.g. male condom and diaphragm, male condom and cervical cap)
• Consumption of more than 2 alcoholic drinks/day, or > 14 alcoholic beverages a week, or history of alcoholism or drug dependence.
• History of allergy to garlic, microcrystalline cellulose, silicon dioxide, magnesium stearate, gelatin, hydroxypropylcellulose, or caramel coloring
• Any planned surgeries any time during the study
• Taking medications with psychotropic properties for less than 3 months, i.e., those taking medications with psychotropic properties, such as anti-depressants, anti-anxiety, etc., at a stable consistent dose for a minimum of 3 months are eligible for the study, as long as the medication is consumed at a stable, consistent dose throughout the study period
• Smokers
• Exercising > 15 miles/wk or 4,000 kcal/wk