Neurólogo alerta sobre riesgos del hexano en alimentos y su vínculo con Parkinson

David Devos sees them every day in his clinic at Lille University Hospital—new patients arriving with the tremors, the stiffness, the slow erosion of movement that marks Parkinson's disease. As a neurologist and pharmacology professor, he has spent two decades developing better treatments, including a pump that delivers dopamine directly to the brain. But he has grown tired of treating the symptoms while the causes remain unaddressed. His recent concern centers on something most people have never heard of: hexane, a colorless liquid derived from crude oil that has become ubiquitous in industrial food production.

Hexane is used to extract oils from seeds—rapeseed, soy, sunflower—at scale and at low cost. It is efficient and economical, which is why it remains the solvent of choice across the food industry. But it leaves traces behind. You will find residues in refined oils, in butter, in milk, in chicken, in soy products. The substance is neurotoxic. It can damage fertility. And a growing body of epidemiological research, particularly from Italy and China, suggests a link between exposure to hexane and the onset of Parkinson's disease. Devos is not alone in his alarm. He has joined other specialists in calling for stricter regulation of hexane use in food production, or ideally, a complete ban.

The challenge is that Parkinson's disease is complex. More than a hundred variables contribute to its development, each accounting for between one and five percent of risk. The disease involves both genetic and environmental factors, and it can take ten to fifteen years to manifest after initial exposure. Diagnosis itself remains difficult. This means that while the association between hexane exposure and Parkinson's is documented in research, proving direct causation requires caution. Scientists must avoid triggering panic while still taking the evidence seriously.

In Spain, hexane is currently permitted in food manufacturing. The National Institute for Safety and Health at Work sets occupational exposure limits—a daily environmental exposure value of 72 milligrams per cubic meter for workplace air—and hexane appears on the official list of approved extraction solvents for food production. Outside of industrial settings, hexane is detected in air near manufacturing facilities but is not considered common in Spanish food or drinking water. Monitoring continues because of documented health risks, and regulations exist to minimize contamination and exposure.

Yet the data on actual hexane residues in refined oils remains sparse and often outdated, according to researchers cited in the scientific literature. This gap in knowledge is itself a problem. We do not have current, comprehensive information about how much hexane remains in the foods we eat. The petroleum origin of the solvent also contributes to atmospheric pollution and requires strict safety controls for workers who handle it. The efficiency and cost-effectiveness that made hexane the industry standard now work against efforts to phase it out.

Devos made his case recently in an opinion piece in Le Monde, arguing for reduced exposure to substances that increase the risk of neurodegenerative disease. He has found a political ally in deputy Richard Ramos, who has backed the proposal for stricter regulation. The question now is whether the evidence of harm, combined with growing medical consensus, will be enough to shift policy. The stakes are measured in cases of Parkinson's disease that might be prevented, in people who might be spared the slow loss of motor control that defines the condition. But the answer depends on whether regulators will act on incomplete data and reasonable concern, or wait for the kind of certainty that may never fully arrive.