Characterizing the Inflammatory Response to a High‐fat Meal in Healthy Adults: A Systematic Review

Abstract

BACKGROUNDInflammation is a prominent feature of many chronic diseases, with poor diet being one likely inflammatory stimulus. Specifically, a single high‐fat meal (HFM) has been shown to increase inflammation, although there is currently no consensus regarding the specific changes of many of the pro‐inflammatory markers that are frequently assessed after a HFM. A synthesis of previous research investigating postprandial inflammation, with particular attention to the specific features of the response, would inform future research and advance clinical understanding.PURPOSEThe aim of this systematic review was to objectively describe the postprandial timing and magnitude of changes of five common inflammatory markers: interleukin (IL)‐6, C‐reactive protein (CRP), tumor necrosis factor (TNF)‐α, IL‐1β, and IL‐8.METHODSTen relevant databases were searched using a comprehensive search strategy, yielding 494 results, of which 47 articles met the pre‐established inclusion criteria: 1) healthy men and women age 18–60 years; 2) consuming a single HFM (≥30% fat, ≥500 kcal); and 3) assessing relevant inflammatory markers post‐meal for ≥2 hours. Study inclusion was assessed and agreed upon by two independent reviewers.RESULTSThe only marker found to consistently change (increase) in the postprandial period was IL‐6, increasing in 71% (32/45) of included studies. On average, IL‐6 was found to start at a baseline of ~1.4 pg/mL and peak at ~2.9 pg/mL approximately 6 hours post‐HFM (an average relative change of ~150%). There was a moderate but significant negative correlation (r = −0.38, p = 0.04) between percent change in IL‐6 from fasting to post‐meal with mean participant age across studies. Post‐meal IL‐6 change was not significantly correlated (p > 0.05) with percent fat in the test meal (r = −0.27), kcal in the test meal (r = 0.24), or mean participant BMI (r = −0.13). C‐reactive protein, TNF‐α, IL‐1β, and IL‐8 did not change significantly in 79% (23/29), 68% (19/28), 67% (2/3), and 75% (3/4) of included studies, respectively.CONCLUSIONOur results suggest that the postprandial inflammatory response to a HFM should no longer include the commonly assessed markers CRP and TNF‐α (and potentially IL‐1β and IL‐8) in healthy humans younger than 60 years of age. However, future research should further investigate the role of IL‐6 in the postprandial period, as it routinely increases, even in health. We assert that the findings of this systematic review regarding markers of inflammation in the postprandial period will considerably aid in informing future research and advancing clinical knowledge.Support or Funding InformationNone