Reusing Cooking Oil Linked to Brain Health Risks Study Reveals

Michael Thompson

Written by Michael Thompson


Recent research has highlighted a concerning link between the consumption of reheated cooking oils and several health risks, particularly in relation to neurological health. The study in question, which presented its findings at Discover BMB 2024 and is set to be published in the Journal of Biological Chemistry, indicates a connection between long-term consumption of reheated oils and increased neurodegeneration. This is a significant concern, as nearly 7 million adults aged 65 and older in the United States are affected by Alzheimer’s, according to the Alzheimer’s Association 2024 report.

The study, led by Dr. Kathiresan Shanmugam and his team at the Central University of Tamil Nadu, focused on the gut-brain-liver axis, a crucial system for maintaining neurological health. The research on rats showed that those fed reheated oils exhibited higher levels of neurodegeneration compared to those fed a standard diet. These findings suggest that the reheating of oil, which disrupts the liver-gut-brain axis, could be linked to an increased risk of neurological disorders.

Oil Reheating: A Common Practice with Uncommon Consequences

Deep frying is a common cooking method used by fast-food restaurants, street vendors, and in home cooking. The process of reheating oil, especially for deep-frying, is widespread due to its cost-effectiveness and the flavor it imparts on food. However, this practice is not without its long-term effects. The reheating and reuse of oils can lead to oxidative stress, inflammation in the liver, colonic damage, and altered endotoxins, as was observed in the diet groups of female rats that mimicked reused oil consumption in the study.

The reheating of cooking oils has been shown to change their chemical structure, reducing beneficial antioxidants and exacerbating the loss of health benefits due to the production of toxins. Alyssa Simpson, a registered dietitian, notes that repeated heating causes oils to break down, affecting fatty acid composition and increasing harmful oxidation products. This chemical alteration can have a substantial impact on our health.

The Detrimental Health Effects of Oxidized Fats

When oils are heated to high temperatures, beneficial antioxidants are reduced, and the oils start to oxidize. Oxidative stress in the brain potentially damages neurons and increases the risk of neurodegenerative diseases. Oxidized fats and advanced glycation end products (AGEs) found in reheated oils are linked to chronic diseases such as Alzheimer’s.

Dr. Alexandra Filingeri, a registered dietitian, emphasizes the negative effects of reheating oil on its nutritional content. The reheated oils are linked to increased cholesterol and inflammation, which are risk factors for cardiometabolic and neurodegenerative diseases. The liver, which plays a detoxifying role in the body, is particularly vulnerable to damage from reheated oils. Oxidized fats could disrupt liver lipid metabolism, leading to conditions like nonalcoholic fatty liver disease (NAFLD).

Moreover, oxidized fats may affect the gut microbiota and intestinal permeability, causing dysbiosis, inflammation, and gut barrier dysfunction. The disruption of the liver-gut-brain axis due to these factors may lead to neuroinflammatory conditions and neurological disorders. Disturbances in specific lipid metabolism could also disrupt brain cell communication and function, further highlighting the dangers of reheated oils.

Protective Nutritional Strategies

To mitigate the harmful effects of oxidized fats, experts recommend diets rich in omega-3 fatty acids and nutraceuticals like curcumin and vitamin E. Incorporating antioxidants, fiber, and polyphenols from various foods can reduce oxidative stress and inflammation. Dietary patterns such as the Mediterranean or MIND diet may help prevent neurodegeneration. Not only do these diets offer protective nutrients, but they also encourage the consumption of foods that are less likely to be fried or reheated in oils.

Frequent intake of fried foods may contribute to weight gain, insulin resistance, and metabolic syndrome, further complicating the health picture. It’s important to choose cooking oils that are high in polyunsaturated fats and to use low-heat preparation methods to preserve their nutritional integrity. Reusing oils for repetitive cooking and high-temperature heating is discouraged due to the potential health risks.

Consumer Choices and Restaurant Practices

Consumers should be aware of the cooking oils used in restaurants and opt for healthier preparation methods when dining out. Inquiring about the type of oil and its use in the cooking process can be an important step in making healthier dietary choices. At home, avoiding the reuse of oils for cooking can help reduce the risk of oxidative stress and preserve liver function.

The study on rats underscores the potential health hazards of reheated oil consumption and calls for mindful dietary choices. It’s important to recognize that while the study’s results provide valuable insights, further research is needed to fully understand how reheated oils impact liver lipid metabolism, gut health, brain health, and neurodegeneration in humans.

Navigating the Landscape of Cooking Oils

Understanding the impact of reheated oils on health is a complex issue that intersects with our daily eating habits, the food industry’s practices, and the need for further scientific investigation. The findings from the recent rat study open the door to a deeper exploration of how our cooking methods can influence long-term health outcomes. It’s an opportunity for individuals to become more informed about the food they eat and for the food industry to evaluate its practices for the well-being of consumers.

As we strive to improve public health, the insights gained from this research can inform policies and guidelines that promote healthier cooking and eating practices. It is a call to action for all stakeholders, from healthcare professionals to food service providers, to work together towards a future where food not only satisfies our taste buds but also supports our neurological and overall health.