Which cooking oil is the most stable under fire?

The way we use cooking oil can have important implications for our health.

- BY EMALIN ZALANI

Universiti Kebangsaan Malaysia toxicologist Associate Professor Dr Razinah Sharif shares that repeated reheating can cause cooking oils to become unsafe for consumption.

Each time oil is heated, its fat molecules start to break down and become unstable, forming harmful byproducts such as aldehydes and free radicals.

These compounds can trigger oxidative stress in the body, damaging healthy cells and tissues.

Constant oxidative stress over long periods of time have been linked to chronic illnesses such as cancer.

Interestingly, not all oils behave the same under high heat.

"If you compare different oils at the same temperature, palm oil actually produces the lowest amount of aldehydes," says Assoc Prof Razinah.

"People often assume palm oil is the worst option, but for deep frying at high temperatures, it generates fewer aldehydes than oils such as olive or canola."

The two biggest concerns are aldehydes and trans fats.

Aldehydes are strongly associated with cancer risk, while trans fats are known to raise the risk of heart disease.

While most people link oil consumption only to heart health, she stresses that its effects extend far beyond that, disrupting many other processes in the body.

Just as different chemicals break down in their own ways, oils also degrade differently when exposed to heat.

"Different oils have different chemical bonds," she explains.

"For example, canola oil, olive oil, palm oil and coconut oil each react differently depending on their structure."

This is why fats are classified as saturated, monounsaturated and polyunsaturated.