A study claims that adults should make sure they get a daily dose of the vegetable oil that chips are often cooked in.

The research revealed that basic cooking oil, popularly used for frying fish, cooking chips and roasting potatoes in millions of homes, is healthier than previously thought. It showed that everyone should be getting up to four tablespoons a day in order to protect their heart, U.S. researchers said, after conducting 15 clinical trials on 500 adults.

Vegetable oil is, typically, made from plants like sunflower, corn or soy and used in both commercial, mass produced cooking and in the home. It is most commonly an alternative to animal-based fats and both cheaper and more practical for day to day cooking than expensive and trendy virgin olive oils, for instance.

The new research by food scientists from the University of Missouri suggests a daily dose, similar to the current average, is actually good for the heart not bad for it.

Vegetable oil, they say, contains an omega-6 fatty acid called linoleic acid (LA) which reduces blood cholesterol levels and lowers the risk of heart disease. The results of their clinical trials on humans found no evidence that LA ‘promotes inflammation’, contradicting a previous study that was conducted on animals, they said.

The full paper, to be published in the Journal of the Academy of Nutrition and Dietetics is just the latest in the see-sawing of medical opinion about vegetable oil. Such oils used to be welcomed as an alternative to the kind of lard and animal fats which had previously been used to fry and roast food.

The boom in fast food from the 1970s saw many health experts claim people were consuming too much oil in their diets as they tucked in to burgers, fries and pizzas.

It has also helped fuel the rise in sales of alternative but expensive trendy oils from virgin olive to walnut. 

Lead researcher, nutritionist Professor Kevin Fritsche, said humans respond differently to vegetable oil, adding: ‘In the field of nutrition and health, animals aren’t people. We’re not saying that you should just go out and consume vegetable oil freely. However, our evidence does suggest that you can achieve a heart-healthy diet by using soybean, canola, corn and sunflower oils instead of animal-based fats when cooking.’

The clinical tests looked at the bodily reactions to adults consuming a variety of different fats, including vegetable oils.

It found the type of inflammation that leads to heart disease was most likely to be a result of too much animal fat rather than vegetable oil, said the researchers.

Professor Fritsche said: ‘Some previous studies have shown that inflammation, which is an immune response in the body, can occur when certain fats are consumed. We’ve come to realise that this inflammation, which can occur anywhere in the body, can cause or promote chronic diseases.We know that animal fats can encourage inflammation, but in this study, we’ve been able to rule out vegetable oil as a cause. Consumers are regularly bombarded with warnings about what foods they should avoid.

He added: ‘While limiting the overall fat intake is also part of the current nutrition recommendations, we hope people will feel comfortable cooking with vegetable oils.’