Macrophage Polarization in Response to Macronutrient Intake in Healthy Humans: A Randomized Clinical Study

Monocyte Differentiation and Macrophage Polarization in Circulation in Response to Macronutrient Intake in Healthy Humans: A Randomized Clinical Study

Macrophages can exhibit distinct phenotypes and functions in response to stimuli and can polarize into one of three distinct phenotypes: a pro-inflammatory (M1), an anti-inflammatory pro-tissue (M2) and metabolically-activated (MMe) macrophage phenotypes. Thirty-six healthy volunteers were recruited and randomized into one of three macronutrient intake groups (glucose, lipids, proteins). This study measured the effects of macronutrient intake on the macrophage differentiation.

Thirty-six normal healthy adult volunteers of normal weight were recruited into the study. All were normotensive, had a normal lipid profile, normal renal and liver function tests, and were not on any medications. All subjects gave their written, informed consent. Institutional Review Board (IRB) of the Ministry of National Guard Health Affairs (MNGHA) approved the study protocol. The 36 participants were randomly assigned by the primary investigator (PI) following simple randomization procedure (computerized random numbers) to three different groups, each received one type of macronutrient (Glucose, whey proteins or lipids). Following an overnight fast, a baseline blood sample was taken. Subjects were then given either 300 calories of glucose (NERL Trutol 75) or lipids (90 grams whipping cream, 31.5 grams fat, 1.7 grams protein and 2.25 grams carbohydrate) or protein (Isopure unflavored Whey proteins isolate (WPI) powder containing 26 grams per serving of 100% WPI, stripped of fat, carbs, fillers, sugars and lactose) solution over 5 minutes. Cream and protein preparations were diluted with water up to 300 mL solutions. Further blood samples were obtained at 1, 2 and 3 hours after the macronutrient intake. Subjects, either one week before or after the macronutrient challenge, were given 300 mL of water to drink in the fasting state. Blood samples were obtained before and at 1, 2 and 3 h after water intake as well. Each subject served as his/her own control and was randomly given macronutrient or water intake.

Inclusion Criteria:

• Normal weight (BMI 18.5-25)
• Healthy adults evident by: physical examination, normal lipid profile, normal renal and liver function tests.

Exclusion Criteria:

• Renal disease
• Hepatic disease
• Cardiovascular disease
• Using multivitamins
• Using NSAIDS