Benzo[a]pyrene, often abbreviated BaP, is everywhere in modern life. It forms whenever organic matter burns incompletely, which means it rises from charcoal grills as fat drips onto hot coals, drifts from cigarette smoke and tailpipes, and accumulates in workplaces such as aluminum smelters, coke ovens and asphalt plants. The International Agency for Research on Cancer classifies it as a Group 1 carcinogen, a category reserved for agents with confirmed cancer-causing activity in humans. Once ingested or inhaled, BaP is metabolically activated by cytochrome P450 enzymes, chiefly CYP1A1 and CYP1B1, into a highly reactive intermediate called BPDE. This compound latches onto DNA to form adducts that can initiate cancer, while the metabolic process itself generates a flood of reactive oxygen species that overwhelm the body’s natural antioxidant enzymes and damage cell membranes, proteins and lipids. Because the liver serves as the body’s principal detoxification organ, it bears the brunt of this chemical assault.

The research team, based at Islamic Azad University in Shahrekord, Iran, set out to test whether dietary intervention could blunt this damage. Seventy male C57BL/6 mice were randomly assigned to fourteen groups of five animals each, with the sample size determined by formal power analysis to satisfy the principles of reduction in animal research. One group received only standard food, another received the olive oil vehicle used to dissolve the chemicals, and a third received 20 milligrams per kilogram of BaP daily by oral gavage for four weeks, a dose previously shown to induce significant oxidative stress and liver and kidney injury in mice without reaching acute lethal levels. A fourth group received vitamin E at 250 milligrams per kilogram, a dose established in earlier studies as antigenotoxic against BaP damage. The remaining groups received chia seed powder mixed into their food at 10, 20 or 30 percent by weight, either alone, alongside BaP simultaneously, or as a two-week pre-treatment before BaP exposure began.

The design allowed the researchers to answer two distinct practical questions. Co-administration tested whether the protective agents could limit damage occurring at the same time as exposure, a scenario relevant to people who cannot avoid contaminated food or polluted workplaces. Pre-treatment tested whether building up the body’s defenses in advance could prevent injury more effectively, a scenario relevant to preventive nutrition. All biochemical analyses were performed in a blinded manner, and the animals were monitored daily for humane endpoints such as excessive weight loss or lethargy, none of which were reached during the study.

The results were unambiguous in one direction and humbling in another. BaP exposure significantly depleted the mice’s total antioxidant capacity and superoxide dismutase activity, raised malondialdehyde, a marker of lipid peroxidation, elevated the liver enzymes AST and ALT, lowered serum albumin, and pushed triglycerides and LDL cholesterol upward. Vitamin E, despite its reputation as a potent fat-soluble radical scavenger, failed to restore antioxidant capacity or superoxide dismutase activity and offered no meaningful protection to the liver enzymes. Chia seeds, by contrast, produced dose-dependent benefits. At 20 and 30 percent dietary inclusion, co-administered chia significantly raised total antioxidant capacity and superoxide dismutase activity while lowering malondialdehyde. Thirty percent chia pre-treatment increased both superoxide dismutase and glutathione peroxidase activities and cut malondialdehyde levels further. Chia co-administration reduced AST at all doses, rescued albumin at the lower doses, lowered triglycerides across the board, and raised protective HDL cholesterol at the higher doses.

The lipid findings were particularly dramatic. BaP exposure drove triglycerides from roughly 1.1 millimolar in controls to 2.44 millimolar, and LDL cholesterol from about 83 to 163 milligrams per deciliter. Chia co-administration at 30 percent brought triglycerides back near baseline while pushing HDL cholesterol to levels well above those of untreated controls. The authors attribute these effects to the seed’s unique biochemical portfolio: alpha-linolenic acid, abundant dietary fiber and a rich array of polyphenols. Mechanistically, chia-derived alpha-linolenic acid appears to activate peroxisome proliferator-activated receptor alpha, boosting fatty acid oxidation, while suppressing sterol regulatory element-binding protein-1, which curbs lipogenesis. Chia components also inhibit fatty acid translocase, known as CD36, limiting fatty acid uptake into tissues, and the seed’s proteins and polyphenols reduce inflammatory signaling through tumor necrosis factor alpha while raising adiponectin.

Why did the whole food outperform the purified vitamin? The researchers argue that BaP’s toxicity is multifaceted, attacking membranes, enzymes, lipid metabolism and DNA simultaneously, and that a single antioxidant molecule simply cannot cover all those fronts. Chia seeds deploy a multitarget strategy: their polyphenols and omega-3 fats act synergistically to neutralize reactive oxygen species directly, and they appear to activate the nuclear factor erythroid 2-related factor 2, or Nrf2, signaling pathway, which switches on the cell’s own antioxidant gene program. Vitamin E, by contrast, may influence CYP1A1 and CYP1B1 activity, but the study suggests this mechanism is insufficient against the scale of oxidative assault that BaP delivers. The authors also note that the vitamin E dose, though previously validated, may have been inadequate for this model, or that the four-week treatment window was too short.

Not every organ responded. BaP raised blood urea nitrogen and creatinine, classic markers of kidney injury, but neither chia nor vitamin E significantly reversed these changes. The researchers suggest that renal protection may require longer treatment durations or different therapeutic approaches, pointing to similar findings with lavender extract against lead-induced nephrotoxicity. The study also has acknowledged limitations: the diets were not isocaloric, body weight and food intake were not formally tracked, tissue-level analyses were not performed, and the potentially synergistic combination of chia and vitamin E was never tested, a question the authors flag as a priority for future work.

The pre-treatment versus co-administration comparison carries a clear public health message. Pre-treatment with 30 percent chia preserved superoxide dismutase and glutathione peroxidase activities and kept malondialdehyde low, suggesting that building antioxidant reserves before exposure is the more effective strategy. For the millions of people exposed to BaP through charred food, secondhand smoke or occupational settings such as coke ovens and aluminum plants, where air monitoring has identified BaP as the dominant carcinogenic risk, the implication is that preventive dietary supplementation matters more than trying to repair damage after the fact. The findings also align with a broader shift in nutrition science away from single-molecule supplements and toward whole-food matrices, whose complex mixtures of bioactive compounds often deliver benefits that isolated nutrients cannot replicate.

Cautious interpretation remains essential. These results come from mice receiving deliberately high doses of both toxin and protective agents, and human trials of chia supplementation in healthy and overweight adults have generally shown only modest changes in lipid profiles and inflammatory markers, likely because those studies lacked a specific toxic challenge. The authors emphasize that clinical and mechanistic studies in humans are needed before dietary recommendations can be made with confidence. Still, the study offers a compelling proof of concept that a common, inexpensive whole food can outperform a flagship antioxidant supplement against one of the world’s most notorious environmental carcinogens, and it suggests that what you eat before exposure may matter as much as the exposure itself.

Subject of Research: Dietary protection against benzo[a]pyrene-induced oxidative toxicity in mice using chia seeds and vitamin E

Article Title: Protective Effects of Chia Seeds and Vitamin E Against Benzo[a]Pyrene‐Induced Toxicity in Male Mice: A Comparison of co‐Administration and Pre‐Treatment Strategies

Article References: Rezaei, M., & Karimi‐Dehkordi, M. (2026). Protective Effects of Chia Seeds and Vitamin E Against Benzo[a]Pyrene‐Induced Toxicity in Male Mice: A Comparison of co‐Administration and Pre‐Treatment Strategies. Food Science & Nutrition, 14(10), Article e72405. https://doi.org/10.1002/fsn3.72405

Image Credits: AI Generated

DOI: 10.1002/fsn3.72405

Keywords: benzo[a]pyrene, chia seeds, vitamin E, oxidative stress, hepatotoxicity, polycyclic aromatic hydrocarbons, antioxidants, mice study, lipid profile, food toxicology, pre-treatment, nutrition