(P39-05-26) Postprandial Lipopolysaccharide Is Higher After a Saturated Than Monounsaturated Fatty Acid Enriched Meal in Older Adults: A Randomized Crossover Study

Objectives: Lipopolysaccharide (LPS), derived from gram-negative bacteria, is associated with inflammation and serum levels increase after high-fat meals, with saturated fatty acids (SFA) potentially producing a greater response than other fatty acids. This study examined whether a SFA-enriched meal, compared with monounsaturated fatty acids (MUFA), differentially affects postprandial LPS and inflammatory responses in older adults with overweight or obesity.

Methods: In a randomized crossover study, older adults consumed a high fat (46%/550 kcal) meal enriched with either MUFA or SFA, while matched for polyunsaturated fatty acid content, energy and macronutrients. Meals included a sandwich of either peanut products (MUFA) or eggs and butter (SFA) to achieve these differences and were given in random order on two separate study days. Blood samples were collected before and 0.5, 2, 3, 4, 5, and 6 hours after the meal to assess LPS, triglycerides, glucose, insulin and inflammatory markers including lipopolysaccharide binding protein (LBP, binds LPS and is a marker of innate immune activation), C-reactive protein, interleukin-6, tumor necrosis factor-alpha (TNF-α), and plasminogen activator inhibitor-1. Body composition was assessed using dual-energy x-ray absorptiometry. Visual analog scale was used to measure appetite.

Results: Participants (n=16, 75% female) were 62.7 ± 4.8 years with a body mass index 33.4 ± 6.3 kg/m² (42% body-fat). The postprandial rise for serum endotoxin at 4 hours was twice as high after the SFA than MUFA meal (p < 0.05) and LBP was also higher (p < 0.05). No other inflammatory markers differed between meals although the rise to postprandial peak LPS and peak TNF-α correlated after the SFA meal (p < 0.05) but not after the MUFA meal. Appetite measures showed no differences between the two meals.

Conclusions: Consumption of the SFA enriched compared to MUFA enriched meal increases peak postprandial LPS and LBP concentrations without a clear upregulation of downstream inflammatory markers.

Funding Sources: The Peanut Institute Foundation, USDA-NIFA (NE1939)