Study Reveals Cooking Garlic and Onions at High Temperatures May Harm Heart Health
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New Delhi, Dec 28 (NationPress) A recent study conducted by researchers in Japan highlights that cooking garlic and onions in vegetable oil at high temperatures can produce trans-fatty acids (TFA), which may negatively impact heart health.
TFAs are harmful fats that can build up along artery walls, limiting blood circulation and heightening the risk of heart attacks.
While TFAs are typically found in processed foods, research indicates that they can also form during home cooking. Investigations show that unsaturated fatty acids (UFAs), often regarded as healthy, can undergo trans-isomerisation—a molecular change that converts them into TFAs when heated to temperatures exceeding 150 degrees Celsius.
To investigate this phenomenon, experts from Meijo University examined the influence of isothiocyanates and polysulfides—sulphur-containing compounds abundant in vegetables like garlic, leeks, onions, scallions, and shallots—on the trans-isomerisation of vegetable UFAs during cooking.
The researchers initially studied the effects of sulphur compounds on triacylglycerols (TAGs) in a model system using various reagents. They then tested garlic, onion, leek, cabbage, horseradish, broccoli sprouts, and vegetable oils such as soybean and olive oils to replicate real cooking conditions.
The findings, published online in the journal Food Research International, revealed that sulphur compounds significantly enhance heat-induced trans-isomerisation of UFAs in vegetable oils, particularly when cooking temperatures exceed 140 degrees Celsius.
Moreover, the team investigated the role of antioxidants like alpha-tocopherol in mitigating the isomerisation of UFAs in triglycerides such as triolein and trilinolein.
While the incorporation of antioxidants considerably decreased the isomerisation of UFAs promoted by isothiocyanates, they had minimal effect on the isomerisation induced by polysulfides.
"This indicates that cooking vegetables rich in polysulfides, such as garlic and onions, in vegetable oil at high temperatures can lead to the production of TFAs. The study illustrates that garlic and onions substantially promote the trans-isomerisation of UFAs," stated the team led by Dr. Masaki Honda at Meijo University.
Conversely, the release of TFAs under standard cooking conditions remains minimal.
"Utilizing ingredients abundant in natural sulphur compounds may elevate the risk of TFA consumption," the researchers noted.
As per the World Health Organization (WHO), TFAs contribute to over 278,000 deaths annually worldwide. The global health organization advises that TFA intake should not exceed 1 percent of daily energy consumption.
