None listed
Conditions
Brief summary
This research study will investigate the effect of the gender and also the combined oral contraceptive pill (OCP) on acute protein-induced thermogenesis. Thermogenesis is the means by which our bodies generate heat whilst using energy to process and store nutrients from the food we eat after meals. This accounts for about 10% of the energy we expend every day. However, there is a large variation between individuals which may contribute to a person’s risk of developing obesity. The OCP is a very common type of female contraception, normally referred to as “The Pill”. Even though the positive effect of dietary protein on thermogenesis and satiety has generated interest in its role in weight control, the relationship between gender, hormonal contraception and protein-induced thermogenesis is not yet fully understood. This study will examine the effect of differing protein levels contained in the test meals on thermogenesis in women of child-bearing age who are either taking or not taking the pill, and men of a similar age. For each group, this will determine if, and by how much, the thermogenic response varies across a range of protein levels, and also reveal potential differences in thermogenesis between the three groups. In addition to monitoring of energy use using a machine called a calorimeter, body temperature will be taken, and blood tests used to measure things like insulin, and cholesterol. This study aims to better understand the differences between men and women, and the effect of the OCP, on thermogenesis after meals containing different protein levels. In addition, we will investigate if rate at which the stomach empties into the small intestine influences thermogenesis, by measuring levels of paracetamol given with the test meals, as nearly all paracetamol is absorbed in the body through the intestine rather than the stomach. The results gained from this study will increase our understanding of the effect of the gender and OCP on thermogenesis after meals of varying protein content. We hope the results will improve obesity treatment/prevention strategies.
Interventions
We will conduct a study of 45 healthy adults aged 18-40 years old, normal and slightly overweight (BMI 18.5 - 27.0). 15 of the participants will be men, 15 women who are users of the combined oral contraceptive pill (OCP+) and 15 women who are not using a hormonal method of contraception (OCP-). We will measure metabolic response to a test meal of known protein content after a 12 hour fast (water allowed) by indirect calorimetry. The test meal will comprise a simple breakfast meal base (toast, b
We will conduct a study of 45 healthy adults aged 18-40 years old, normal and slightly overweight (BMI 18.5 - 27.0). 15 of the participants will be men, 15 women who are users of the combined oral contraceptive pill (OCP+) and 15 women who are not using a hormonal method of contraception (OCP-). We will measure metabolic response to a test meal of known protein content after a 12 hour fast (water allowed) by indirect calorimetry. The test meal will comprise a simple breakfast meal base (toast, butter, jam) with either a dairy based drink to which protein powder may be added to increase the protein content as necessary, or non-dairy drink (coconut milk base). The energy provided by the isocaloric test meals is 2468 kJ, (590kcal), typical of a light meal. Participants will be asked to consume the test meal within 10 minutes. Each participant will attend the Human Nutrition Unit in central Auckland 3 times over approximately 2 months, and consume a test meal of differing protein content at each visit. The protein content of the meal is either low (5%), normal/control (11%) or high (25%). Each visit being a maximum of 6 hrs in length, and there will be a minimum / maximum interval between visits of 2 days / 2 months respectively for individual participants. A subset of OCP+ women will be invited to return for an additional 2 visits during their inactive pill phase. A small dose of soluble paracetamol (1.5g) dissolved in 100ml of water will be given for participants to drink with the meal, in order to measure the rate of gastric emptying, as paracetamol is not well absorbed in the stomach, but is in the small intestine. The protocol for administration of the meal and paracetamol will be the same at each visit, with adherence assessed by the research personnel supervising, who will be present in the room with the participant during this time. The time taken to consume the entire test meal and paracetamol will be recorded at each visit. Indirect calorimetry measurement will be untaken by PhD student and assisted by a research assistant, each experienced in such measurements, who have both been trained in the procedure by Dr. Jennifer Miles-Chan, a Senior Research fellow with approximately 10 years post doctorate experience in this technique. Prior to indirect calorimetry measurement, a cannula will be inserted into a participant's vein by a trained nurse, to allow blood sampling (8 samples taken, total 79ml) over the 4.5hr of measurement. During the indirect calorimetry measurement, participants will be seated and will be able to watch a calm movie and/or documentary from a selection available in order to pass the time.
Sponsors
Dr. Jennifer Miles-Chan
Study design
Allocation
Randomised controlled trial
Primary purpose
Treatment
Eligibility
Sex/Gender
All
Age
18 Years to 40 Years
Healthy volunteers
Yes
Inclusion criteria
Provision of informed consent Adults aged 18-40 years BMI 18.5 - 27.0 Self reported healthy For female participants OCP+, regular (>3 months) of a combined oral contraceptive pill, as per manufacturers instructions i.e. with regular withdrawl bleeding. For female participants OCP-, no hormonal method of contraceptive used for at least 3 months, with regular menses.
Exclusion criteria
History of chronic disease, or endocrine disorder (both males and females) Breast feeding, pregnancy or history of menstrual disorder (females) Use of any medication during the last 3 months (other than the combined oral contraceptive pill for OCP+ women) Allergy or adverse reaction to paracetamol Vegetarian Claustrophobia
Outcome results
None listed