None listed
Conditions
Brief summary
Excessive accumulation of fat in the body, particularly around the internal organs, is associated with increased risk of type 2 diabetes and cardiovascular disease. Hence the prevention and management of body fat accumulation is important and diet plays an important role. Dietary saturated fatty acids are often implicated to cause more fat deposition than unsaturated fatty acids, despite limited scientific evidence to support this notion. Very few studies to date have directly compared different types of fats and the results are inconsistent. Inconsistencies may be explained by differences in the chemical structure of different dietary saturated fat sources. Specifically the way in which fatty acids are distributed within triglyceride (lipid) molecules may affect their absorption and hence their physiological and biochemical responses. In light of this, the main aim of the study is to compare the effects of three vegetable fats (palm olein, cocoa butter and soybean oil), differing in their content of saturated fatty acids but comparable in chemical structure, on changes in fat deposition in the body (specifically liver and fat tissue content) in a healthy population. The primary hypothesis is that consumption of dietary fats high in SFA (palm olein and cocoa butter), but containing the majority of SFA in sn-1, 3 positions with mostly unsaturated fatty acids in the sn-2 position will not result in unfavourable body fat accretion compared to a dietary fat high in unsaturated fatty acids (soybean oil).
Interventions
Palm olein (POo), Cocoa butter (COB) and Soybean oil (SBO) (control) will be compared using a 16-week blinded, randomised, 3-arm parallel feeding study design preceded by a 2-week run-in period.
A highly controlled feeding protocol will be used - Participants will consume the same background diet (35%E fat, 18%E protein, 48%E carbohydrate) differing in test fats only. Test fats will provide 20%E as either POo, COB or SBO and will be delivered through meals and snacks. The run-in diet will be th
Palm olein (POo), Cocoa butter (COB) and Soybean oil (SBO) (control) will be compared using a 16-week blinded, randomised, 3-arm parallel feeding study design preceded by a 2-week run-in period. A highly controlled feeding protocol will be used - Participants will consume the same background diet (35%E fat, 18%E protein, 48%E carbohydrate) differing in test fats only. Test fats will provide 20%E as either POo, COB or SBO and will be delivered through meals and snacks. The run-in diet will be the same background diet as the intervention diet containing POo as major fat type. The prescribed diets will be eucaloric to maintain body weight stability. Whole diets will be designed at different levels of energy in increments of 1500 kJ for adjustment to individual energy requirements. Participant’s individual energy requirements will be determined using the Schofield equation based on age and gender. Participants will then be assigned the closest 1500 kJ bracket. Participants will be requested not to consume any other high-fat foods and to consume all food supplied. All test meals and snacks will be provided to participants for the duration of the study. The test fats will be delivered within one main meal per day (either lunch or dinner) and snacks consumed in-between meals (biscuits/cake). The remaining diet will consists of low-fat meals and snacks including breakfast cereal (supplied) and a low-fat meal prepared by participants themselves according to prescribed guidelines. Daily ‘low-fat snacks’ (non-study snacks) will be prescribed as part of the dietary pattern. These will be fruit, low-fat dairy or bread and cereal options, and participant will have some flexibility to swap their low-fat snack allowances for low-fat discretionary product/s from a prescribed list which includes alcoholic beverages. Pre-intervention, participants will attend a dietetic consultation regarding the dietary intervention (~45 minutes). Compliance will be monitored using an online checklist that participants complete weekly. If deviations from the dietary protocol is reported, participants will be contacted by the dietitian to determine possible reasons for the deviation and adjustments to the prescribed energy intake level will be made if required. Compliance will also be cross-monitored during a brief consultation with a dietitian at each visit (~10 min per 4 weeks over 16 weeks).
Sponsors
CSIRO Health and Biosecurity
Study design
Allocation
Randomised controlled trial
Intervention model
Parallel
Primary purpose
Treatment
Masking
Blinded (masking used) (Subject, Caregiver, Investigator, Outcomes Assessor)
Eligibility
Sex/Gender
All
Age
20 Years to 45 Years
Healthy volunteers
Yes
Inclusion criteria
1. Healthy adults 2. BMI 18.5-27.5 kg/m2 3. Understand the study requirements and willing to adhere closely to prescribed food consumption as per the research protocol
Exclusion criteria
1. Self-reported history of any of the following chronic diseases - type 2 diabetes, hypertension, coronary heart disease, hyperlipidemia, liver disease, cancer (excluding skin cancer), haemochromatosis 2. Self-reported history of pancreatic insufficiency or other conditions resulting in fat malabsorption - chronic pancreatitis, cystic fibrosis, coeliac disease, Crohns disease, gastric bypass surgery, small bowel resection, abnormal thyroid function 3. On medication/nutraceuticals that may affect liver function, blood lipids, blood pressure or body weight, as assessed by the Principal Investigator or designee 4. Self-reported history of claustrophobia – to enable MRS/MRI assessments to be performed 5. Presence of any ferrous metal in the body - to enable MRS/MRI assessments to be performed. 6. Self-reported pregnant or currently lactating women 7. Females who are post-menopausal, on hormone replacement therapy or on hormone based contraceptives, unless they are stable for at least 3 months prior to study commencement (no changes in type and dose) and have no intention to change during study 8. History of smoking during the 6 months prior to the study 9. Alcohol consumption >21 units per week for men & >14 units per week for women 10. Mean blood pressure >140/90 mmHg assessed at screening visit 11. Hyperlipidemia (fasting TC>6.2 mmol/L or TAG >2.0 mmol/L) assessed at screening visit 12. Abnormal serum liver enzymes (ALT, AST) assessed at screening visit 13. Extended absences due to travel or other commitments 14. Self-reported known allergies to intervention foods 15. On any weight-loss program
Outcome results
None listed