Postprandial Effects of Milk Fats

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. With this study the investigators want to examine the effects of a vegetable fat blend versus bovine milk fat without globular membranes and bovine milk fat with globular membranes on underlying mechanistic, immune and metabolic responses.

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).

Eligibility Criteria:
Inclusion Criteria:

* Apparently healthy man or woman
* Age 40-70y at the time of recruitment
* BMI of 22-27 kg/m2
* Having a Hb value above 8.4 (men) or 7.4 (women) mmol/L (will be checked at the screening visit)
* Having veins suitable for blood sampling via a catheter cannula (judged by study nurse/ medical doctor)
* Having a general practitioner
* Signed informed consent

Exclusion Criteria:

* Any chronic metabolic, gastrointestinal, inflammatory or chronic disease (such as diabetes, anaemia, hepatitis, cardiovascular disease)
* History of gastro-intestinal surgery or having (serious) gastro-intestinal complaints
* Renal or hepatic malfunctioning (pre-diagnosis or determined based on ALAT, ASAT and creatinine values)
* Use of medication that may influence the study results, such as laxatives, stomach protectors and drugs that can affect intestinal motility.
* Donated or intend to donate blood from 2 months before the study until the end of the study
* Reported slimming, medically prescribed or vegan diet
* Unstable body weight (weight gain or loss \>5 kg in the past three months)
* Current smokers
* Alcohol on average: more than 2 consumptions/day or more than 14 consumptions/week
* Pregnant, lactating or wishing to become pregnant in the period of the study (self-reported)
* Use of illicit drugs
* Food allergies for products that the investigators use in the study
* Participation in another clinical trial at the same time, or in the month preceding the start of this study
* Inability to understand study information and/or communicate with staff
* Members of the research team
* Working, or doing an internship or thesis at the division "Human Nutrition and Health", Wageningen University