RFK Jr., Donald Trump’s pick to head the us Health and Human Services Department, wrote on X that Americans are being “unknowingly poisoned” by seed oils. He joins the growing list of people claiming that these oils are toxic. But are they?

Seed oils include sunflower, rapeseed, corn and grapeseed oils. High heat, chemical solvents and extreme pressure are used to extract the oil from plant seeds. They are then further refined to stabilise it.

These refining processes can affect the chemical compounds of the oil, reducing the amount of healthy antioxidants, polyphenols and phospholipids. However, this process gives the oil a longer shelf life and stabilises the oil so that it doesn’t burn at high temperatures

Many social media influencers claim that seed oils contain toxins. But most of these compounds, such as pollutants and heavy metals, are removed during refining. The amount that is left is too small to cause humans any harm.

The main issue with these oils is that some fast-food outlets reuse them to cut costs. Once reused and reheated, trans fats, which increase “bad cholesterol” and decrease “good cholesterol”, can form in the........

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