The Effects of Different Fat Structures on Postprandial Responses in Healthy Subjects

Rationale: Human milk is considered as the ideal food for full-term infants. The composition and function of human milk is unique and has provided the basis for the development of modern artificial milk formulas that mimic its complex biological positive effects on infants and can provide an appropriate substitute for non-breastfed infants. An important component in human milk are the lipids, as they deliver 50% of the total energy to infants. Nowadays, mostly vegetable fat blends are used in infant formula, but the use of bovine milk fat is increasing. In terms of fat structure, bovine milk fat and vegetable fats differ. Bovine milk fat has a higher percentage of palmitic acid attached to the sn-2 position of the glycerol backbone compared to vegetable fat blend. Also bovine milk fat contains milk fat globular membranes, as opposed to vegetable fat. Knowledge on how these differences influence underlying mechanistic, immune and metabolic responses is lacking.

Objectives: The primary objective of this study is to determine the effect of three different fat blends on underlying mechanistic and immune responses in the circulation. The secondary objectives of this study are: 1) to examine the effects of the three different fat blends on postprandial triglyceride concentration and other cardio-metabolic markers in the circulation, 2) to investigate the effect of the three different fat blends on postprandial feelings of hunger and satiety, and 3) to investigate how comparable cytokine measurements are in blood samples obtained via a catheter cannula compared to cytokine measurements in dried blood spots obtained via a finger prick.

Study design: The POEMI Study is a double-blind randomized cross-over acute intervention study in which each research subject will visit the university on three separate occasions with a wash-out period of at least one week. At each visit the research subject will undergo one of the three dietary lipid challenge tests (a shake) in a randomized order. On each study day research subjects will be asked to clock in 30 minutes prior to the first data collection points and a catheter cannula will be inserted in a antecubital vein. After the 30 minute rest, blood will be drawn from the catheter cannula and via a finger prick (baseline measurements, t0). After the baseline measurements, the research subjects will have to consume the shake within a time frame of 10 minutes. Blood is again drawn from the catheter cannula at t= 1, 2, 3, 4, 5, 6, 7, and 8 hours after consumption, with an additional finger prick at t=6. A questionnaire on hunger and satiety feelings will be taken after every blood draw.

Study population: The base population will consist of 40 healthy men and women with a BMI ranging from 22 to 27 kg/m2, aged 40 to 70 years old, selected from the surroundings of Wageningen through the mailing list for potential study research subjects of the division of Human Nutrition and health of Wageningen University. If needed, additional recruitment of research subjects will take place by flyers and posters, or advertisements in local newspapers.

Intervention: The dietary lipid challenge tests will be provided in the form of a liquid shake (0.6 L). Each shake will contain 95 gram of fat. The three types of fat that will be tested include: a) 100% vegetable fat blend, b) 100% Anhydrous milk fat (AMF), c) 100% cream (AMF + milk fat globular membranes).