The postprandial inflammatory response after ingestion of heated oils in obese persons is reduced by the presence of phenol compounds.
Level 2 - randomized trial
Individual randomized crossover trial in humans
PubMed 22162245 · doi:10.1002/mnfr.201100533
What was done
Twenty obese participants completed a randomized crossover study testing the acute postprandial inflammatory response to four test breakfasts (milk and muffins). The muffins were prepared using oils subjected to 20 heating cycles: virgin olive oil (VOO), sunflower oil (SFO), or a sunflower/canola seed oil mix enriched with either dimethylpolysiloxane (SOD) or phenolic antioxidants derived from olive mill wastewater alperujo (SOP). Investigators assessed peripheral blood mononuclear cell (PBMC) inflammatory markers—including nuclear NF-κB activation, cytoplasmic IκB-α, and mRNA expression of NF-κB activators (p65, IKKα, IKKβ) and inflammatory cytokines (TNF-α, IL-1β, IL-6, MIF, JNK)—as well as plasma lipopolysaccharide (LPS) levels.
What was found
The abstract does not report exact numerical values or effect sizes. Directionally, meals containing phenol-rich oils (VOO and SOP) reduced nuclear NF-κB activation, increased cytoplasmic IκB-α levels, and decreased plasma LPS concentrations compared to SFO. Conversely, the heated sunflower oil (SFO) meal increased mRNA levels of IKKα, IKKβ, p65, IL-1β, IL-6, MIF, and JNK in PBMCs, alongside increased plasma LPS.
Why it matters
Thermal processing of cooking oils can promote postprandial inflammation, but the presence of phenolic compounds—either naturally present in virgin olive oil or added from olive processing byproducts—appears to attenuate acute postprandial inflammatory signaling and endotoxemia.
Limits
The sample size was small (n = 20) and restricted to obese adults, limiting generalizability to other populations. The abstract omits precise quantitative measurements, baseline values, and confidence intervals. Findings reflect acute surrogate cellular and molecular markers following heavily heated oils (20 cycles), which may not translate to chronic health outcomes or typical lower-heat culinary practices.
Cited by
- partial Human studies comparing muffins baked with unheated oil versus repeatedly heated oil (such as safflower oil heated 20 times) found that heated oil increased inflammatory markers and oxidized LDL.