Effect of frying oils on the postprandial endoplasmic reticulum stress in obese people.
Level 2 - randomized trial
Randomized crossover trial in humans
PubMed 25164487 · doi:10.1002/mnfr.201400401
What was done
Twenty obese individuals participated in a randomized crossover study evaluating the postprandial effect of four different frying oils subjected to 20 heating cycles. Participants consumed test breakfasts consisting of muffins prepared with virgin olive oil (VOO), sunflower oil (SFO), or a seed oil mixture (sunflower/canola) with either dimethylpolysiloxane (SOD) or natural olive antioxidants (SOP). Endoplasmic reticulum (ER) stress was assessed by measuring mRNA levels of sXBP1, BiP, CRT, and CNX in peripheral blood mononuclear cells.
What was found
Intake of muffins made with heated sunflower oil (SFO) induced a postprandial increase in the mRNA levels of sXBP1, BiP, and CRT (all p < 0.05). The abstract does not report baseline values, absolute numerical changes, confidence intervals, or specific statistical comparisons for the other oil conditions (VOO, SOD, SOP) and the CNX marker.
Why it matters
Repeatedly heated vegetable oils can trigger postprandial inflammation, and this study identifies cellular endoplasmic reticulum stress as a potential mechanism mediating the adverse metabolic effects of heated sunflower oil in obese individuals.
Limits
The sample size was small (n = 20) and restricted to obese participants, limiting generalizability. The abstract omits exact numerical values, effect sizes, and results for comparator oils. Only mRNA expression in circulating immune cells was measured rather than protein levels or direct tissue-level ER stress.
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.