None listed
Conditions
Brief summary
This study will determine if macadamia nuts are an appropriate food to include in diets to address weight loss and other factors associated with coronary heart disease.
Interventions
A description of the study: Once recruited, subjects will be randomly assigned to either a test pre-entry diet or control group. The test pre-entry ‘loading’ group will have their usual (baseline) diet assessed to determine their overall energy intake and percentage contribution of energy nutrients as well as fatty acid (FA) composition. Based on the percentage of their dietary fat intake, Macadamia nut and oil products will be provided to substitute a major proportion (~20%) of the usual sour
A description of the study: Once recruited, subjects will be randomly assigned to either a test pre-entry diet or control group. The test pre-entry ‘loading’ group will have their usual (baseline) diet assessed to determine their overall energy intake and percentage contribution of energy nutrients as well as fatty acid (FA) composition. Based on the percentage of their dietary fat intake, Macadamia nut and oil products will be provided to substitute a major proportion (~20%) of the usual source of dietary fat without affecting total daily energy intake, i.e. isocaloric with usual baseline diet. This pre-entry ‘loading’ phase will continue for a period of 10 weeks, after which time subjects from each of the test pre-entry ‘loading’ diet and control groups will be randomly assigned to one of two different energy-controlled weight reduction diets. In the energy-controlled (second) phase of the trial, the test diet will consist of moderately high fat intake (35-40%) with a large proportion (~20%) derived from macadamia nuts. Each diet will be progressively adjusted to facilitate a reduction in body weight of 0.5-1.0 kg per week. The test period will endure 6 months duration in the first instance, with subjects being monitored regularly over a period of up to 18 months. This protocol will involve regular face-to-face consultations over this time to enable collection of samples and present opportunities to sustain adherence to the dietary protocol. Specifically visits at 0, 1, and 4 weeks, followed by two-monthly visits during the weight loss protocol will be conducted for subject monitoring. Additional consultation will be provided as required for each subject. Dietary data in the form of 3-day food records, 24 hour dietary recall and food frequency questionnaires will be taken to monitor adherence. Non-invasive anthropometric measures (BMI, waist and hip circumference, bioelectrical impedance) and endothelial function tests will be conducted as well. Blood samples will be taken both to screen for subject eligibility and to provide information on risk factors such as serum lipids, markers of inflammation and to cross-validate dietary data. A proportion of samples will be allocated to low temperature storage to enable retrospective biochemical analysis. Pre-Entry Intervention Group: Usual diet modified to allow for pre-determined amount of macadamia nuts. Weight Loss (energy-controlled) Phase Intervention Group: a moderately high fat (close to 35% of energy) monounsaturated fat-enriched, energy-controlled, weight loss diet including a pre-determined amount of macadamia nuts daily.
Sponsors
Griffith University
Study design
Allocation
Randomised controlled trial
Intervention model
Parallel
Primary purpose
Prevention
Masking
Open (masking not used)
Eligibility
Sex/Gender
All
Age
26 Years to 55 Years
Healthy volunteers
No
Inclusion criteria
BMI 27-50 kg/m2; waist circumference F= >88 cm, M= >102 cm; non-smoker >1 year; blood pressure systole >100 and <140 mmHg, diastole <90mmHg; total fasting cholesterol less than 260mg/dl; total fasting triglycerides less than 400 mg/dl; total fasting glucose less than 126 mg/dl; normal liver and kidney function; willing to modify diet and other health behaviours; not planning to become pregnant or move during the study; have no food allergies to nut products; subjects must not be currently following any particular diet and must not have intentionally lost weight by dieting during the previous 3 months; subjects must not be taking nutritional supplements other than a daily multivitamin (or be willing to stop taking nutritional supplements if needed); subjects must be willing to maintain current physical activity routine, which cannot exceed the equivalent of >30 minutes per day or moderate-intensity activity; Blood hematocrit normal; subjects must be willing to comply with all study-related procedures; not using medication (insulin or oral) to control blood sugar.
Exclusion criteria
Any medical condition that may make weight loss medically inadvisable; history of kidney failure or disease; cancer diagnosis within 2 years prior to study entry; consumption of more than 3 alcoholic drinks a day; type I or type II diabetes; current use of hypolipidemics, anti-psychotics; hypoglycaemics, glucocorticoids or thyroid medication; plan to move during the study; current participation in another clinical trial; pregnancy or breast-feeding; liver disease; high cholesterol; diabetes; HIV positive; Syphilis; Hepatitis B/C positive; does not meet age requirement; habitual smoker; food allergies; unwillingness to provide written consent; personal history of cardiovascular disease, including prior myocardial infarction, angioplasty, or bypass surgery; known cardiovascular or metabolic disease; currently using medications to control blood pressure, lipids or glucose; currently on diet or attempted weight loss by dieting in last 3 months; currently exercising more than the equivalent of 30 minutes/day or moderate intensity physical activity; currently on oral contraceptives; history of alcohol or drug abuse; known allergy or sensitivity to nuts; known atherosclerotic cardiovascular disease; history of congestive heart failure; history of non skin malignancy in previous 5 years or skin malignancy in previous 2 years; any major active rheumatologic, pulmonary, hepatic, renal, dermatologic disease or inflammatory condition; history of HIV positive; weight loss inducing medications or dietary supplements within 3 months prior to enrolment; weight loss > 5kg in last 6 months; serious or unstable medical or psychological conditions that, in the opinion of the investigator, would compromise the subject’s safety or successful participation in the study.
Outcome results
None listed