This Is the Unhealthiest Cooking Oil
Refined sunflower oil, found in most Croatian kitchens, promotes inflammatory processes due to its chemical instability and puts long-term strain on the liver and gallbladder.
Refined sunflower oil, found in most Croatian kitchens, promotes inflammatory processes due to its chemical instability and puts long-term strain on the liver and gallbladder.
A bottle of sunflower oil sits in nearly every Croatian home. It's used for frying, baking, and salads, but few stop to wonder what happens to it when it reaches high temperatures in the pan. The consequences of daily use aren't immediately visible, but when they do appear, they're the result of years of using this very oil.
Refined sunflower oil, especially the kind high in linoleic acid, is considered one of the most problematic choices for everyday cooking. The key reason is its chemical instability. Linoleic acid, a polyunsaturated fatty acid, oxidizes when exposed to heat, light, or air. When heated to high temperatures, as is common in households and restaurants, it creates compounds that promote inflammatory processes in the body.
The story begins in the 1970s and 1980s, when dietary guidelines in the United States began promoting a low-fat, high-carbohydrate diet. At that time, saturated fats were blamed for heart problems, while polyunsaturated oils like sunflower, soybean, and corn oil were marketed as healthier options. The food industry quickly adopted them because they're cheap to produce and have a long shelf life.
Later research showed that lowering cholesterol with these oils didn't significantly reduce the risk of heart disease, contrary to expectations. Still, these oils remained in the food chain, mainly because they serve as preservatives in processed foods. Nearly every package of cookies, chips, or ready-made sauce lists one of them on the label.
The refining process involves high-temperature extraction, bleaching, and deodorization. Each of these steps strips away beneficial compounds from the raw seeds while increasing the oil's tendency to oxidize. In contrast, cold-pressed oils retain antioxidants that naturally protect fatty acids from degradation.
Fresh oil from the mill goes bad after a few days, just like fresh bread. Refined oil, however, stays edible for months. This longevity isn't a sign of quality but rather an indication that the product is so heavily processed that microorganisms no longer consider it food. Gut microbes also struggle to digest highly processed oils, so instead of nourishing the microbiome, the body expends extra energy on liver detoxification.
Chronic consumption of such oils strains the liver and gallbladder, and over time, it can contribute to the buildup of biliary sludge. This is one reason why surgical removal of the gallbladder is now one of the most common abdominal procedures worldwide. It's the result of years of exposure to fats that the body struggles to break down.
The ratio of omega-6 to omega-3 fatty acids is crucial. In the past, these two types of fats were consumed in a ratio close to 1:1. Due to refined oils like sunflower oil, today's diet pushes that ratio to as high as 20:1 in favor of omega-6. Such an imbalance keeps the body in a state of mild, chronic inflammation, which is linked to a range of modern health issues.
Sunflower oil isn't the only problematic one. Soybean, corn, refined canola, and cottonseed oils share similar characteristics: high omega-6 content, heavy industrial processing, and easy oxidation at high temperatures. Cottonseed oil is particularly concerning because it's a byproduct of the textile industry, often containing pesticide residues.
What makes them insidious is their prevalence. The bottle in your cupboard isn't the whole story-these oils are also found in restaurant food, packaged products, and store-bought salad dressings. The average person consumes them dozens of times a week without even realizing it.
Olive oil, especially extra virgin, remains one of the most reliable choices thanks to its high oleic acid and polyphenol content, which reduce oxidative stress. However, caution is needed when purchasing. A study from the University of California, Davis, found that much olive oil labeled as extra virgin doesn't actually meet the required standards, whether due to oxidation, poor processing, or blending with cheaper refined oils.
Clarified butter, known as ghee, especially from grass-fed cows, is also a good option for high-heat cooking. It contains butyric acid, which supports gut lining health, and the production process removes lactose and casein. Avocado oil and macadamia oil, both cold-pressed, are also more stable options because they're high in monounsaturated fats.
The simplest indicator is the word "refined" on the label, along with names like sunflower, soybean, or corn oil. Another sign is an unusually long shelf life compared to cold-pressed oils, which typically spoil within a few months of opening. The third, and perhaps most important, factor is its position on the ingredient list-if oil is among the first three ingredients, it's often a cheap, highly processed version.
Swapping out one bottle in your kitchen might seem like a small step, but in the long run, it affects digestion, inflammatory processes, and the health of your heart and liver.
