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

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:

• 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.
• 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