None listed
Conditions
Brief summary
Kawakawa (Piper excelsum) is endemic to Aotearoa, New Zealand, and, as a taonga, is of great cultural importance to Maori. Kawakawa is used extensively in rongoa Maori (traditional Maori healing). The pharmacology of kawakawa is complex, with studies reporting kawakawa to contain several biologically active compounds that influence inflammation and related pathways. For example, myristicin inhibits the production of several pro-inflammatory cytokines, such as NO, IL-6 and IL-10, in mouse macrophages and THP-1 monocytes. Elemicin, another aromatic compound in kawakawa, is known to play a role in inhibiting IL-6. We hypothesize that the consumption of kawakawa would impact the inflammatory pathways by enhancing anti-inflammatory effects. However, several confounding variables, such as individualized differences in kawakawa tea preparation and doses and variability in the bioavailability of the active kawakawa constituents, could also alter the anti-inflammatory effects. Therefore, controlled human kawakawa trials are necessary to evaluate the effects of different doses of kawakawa consumption on inflammatory markers. To test our hypothesis, this study aims to quantify the effects of different kawakawa doses on inflammatory markers in healthy human volunteers.
Interventions
The study will involve Three randomised interventions provided as capsules to the participants.
Intervention 1: 4 capsules; each containing 0.25g dry weight of kawakawa to be consumed daily in the morning for one week
Intervention 2: 4 capsules; (2 capsules each containing 0.25g dry weight of kawakawa to be consumed daily for 1 week + 2 capsules each containing 0.25g cellulose (metabolically inert) as a placebo to be consumed daily for 1 week.
Control: 4 capsules, each containing 0.25g cellulose
The study will involve Three randomised interventions provided as capsules to the participants. Intervention 1: 4 capsules; each containing 0.25g dry weight of kawakawa to be consumed daily in the morning for one week Intervention 2: 4 capsules; (2 capsules each containing 0.25g dry weight of kawakawa to be consumed daily for 1 week + 2 capsules each containing 0.25g cellulose (metabolically inert) as a placebo to be consumed daily for 1 week. Control: 4 capsules, each containing 0.25g cellulose (metabolically inert) as a placebo to be consumed daily for one week Oral glucose tolerance test will be performed (OGTT) with a 75g glucose load on six different occasions: Intervention Visits 1 &2; (at baseline and after one week of consuming kawakawa capsules); Intervention Visits 3 & 4: (baseline and after one week of consuming placebo capsules) and Intervention Visits 5 & 6: (baseline and after one week of consuming kawakawa+placebo capsules) (randomised cross-over design). Owing to the cross-over design of the study, a 2-week washout period between the three interventions will be observed. Since the postprandial state lasts for approximately 3-5 h post-meal period, the participants must attend the Clinical Research Unit (CRU) of the Liggins Institute on each intervention visit for 3 hours. Participants will be provided with a simple, standardised meal to eat the evening before each study visit to reduce variability in the fasting substrate oxidation profile. This meal will have identical macronutrient composition and energy content (300gm weight; 526-kilo calories; 50 grams protein; 35 grams fat; 34.3 grams carbohydrates < 1.6 % Sugars) within- and between participants and is to be consumed between 7:30 and 8 pm. Participants will also be advised to abstain from intense exercise and caffeinated and alcoholic drinks in the 24hrs prior to the study visits. Participants are required to come in an overnight (12 h) fasted state. Upon arrival, the participant’s anthropometric measurements (weight and waist circumference) will be taken, and a spot urine sample will be collected. Participants will then be asked to sit in a comfortable seat in a quiet, temperature-controlled (20-22°C) laboratory. Body temperature will be measured using a tympanic thermometer to exclude the presence of fever. A peripheral venous cannula will be inserted by the Research Nurse for repeated blood sampling. A 16mL fasting baseline blood sample will be collected. Following the fasting sample, a standard oral glucose tolerance test (OGTT) will be performed. Participants will be provided with 75g of glucose drink to be consumed within 10 minutes. Blood samples will be collected at intervals of 30, 60, 90, and 120 mins from an arm vein. A total volume of 70mL will be taken at each study visit. Urine samples will be collected at fasting and then over 3 hours after glucose consumption. During the one week of each intervention, participants would be asked to maintain a record of their capsule intake by filling out the record form provided to them on visit 1. Also, participants are required to return the capsules at the end of each intervention.
Sponsors
Liggins Institute, The University of Auckland
Study design
Allocation
Randomised controlled trial
Intervention model
Crossover
Primary purpose
Prevention
Masking
Blinded (masking used) (Subject, Caregiver)
Eligibility
Sex/Gender
All
Age
18 Years to 45 Years
Healthy volunteers
Yes
Inclusion criteria
• Gender: both males and females. • Age: 18-45 yr. • BMI: 18-25kg/m2 • Non-smokers • Able to refrain from taking herbal teas • Self-reported not consuming herbal/botanical supplements or traditional extracts • Self-reported healthy
Exclusion criteria
• Are taking herbal supplements or herbal remedies which may affect the study outcome • Are allergic to pepper, nutmeg or similar spices • Are diagnosed with gastrointestinal disease (i.e. celiac, Crohn’s, colitis, etc.) or pre-existing metabolic disease • Are currently taking medications expected to interfere with normal digestive or metabolic processes including proton pump inhibitors, laxatives, etc. • Have used antibiotics within the previous one month or were on long-term antibiotic therapy. • Have a medical history precluding a healthy state: history of myocardial infarction, angina, stroke, cancer or pre-existing diabetes • Have recently gained or lost around >5% body weight
Outcome results
None listed