We've heard a lot about palm oil just recently. It raises cholesterol and therefore increases the risk of heart problems, and its manufacture generates contaminants which are potentially carcinogenic, according to the European Food Safety Authority (EFSA); a study carried out by IRB Barcelona says palm oil feeds cancerous cells and induces metastasis; cooking with palm oil contributes to obesity. But which of these claims have actually been proved?
The first one is based on facts which have been checked and confirmed: "Palm oil is a vegetable oil which contains saturated fats that raise the bad cholesterol (LDL) which becomes deposited in our arteries," said Dr Petra Sanz of the Spanish Heart and Cardiology Foundation at the Rey Juan Carlos hospital in Madrid. "Regular consumption can raise cholesterol levels and, together with other risk factors such as diabetes, hypertension and smoking, means that too much cholesterol circulates through the blood, is deposited in our arteries and obstructs them," she explained.
However, avoiding this type of fat involves a certain amount of effort by the consumer, because it is increasingly being used by the food industry in biscuits, bakery products and other items. "It is sometimes difficult to find a biscuit or pastry which doesn't contain this type of fat," said Dr Sanz.
The second claim has also been confirmed. When palm oil is used in food production, if temperatures rise above 200ºC the contaminants glycidyl esters (GE) are a health risk for people of all ages who have high levels of exposure to them.
The EFSA is not recommending that we stop consuming these products, while it awaits further studies to evaluate the level of risk. However, whenever a product is classified as "probably carcinogenic", consumers associations call for special independent monitoring to be carried out, no matter what type of oil is used, because "these types of contaminants are not exclusively found in palm oil but also other types of refined vegetable oils, such as soya and corn, although the quantities are lower in those cases," said sources.
The third claim about vegetable oils, and especially palm oil - that it can encourage the spread of cancer - still lacks sufficient testing in laboratories and on humans.
"Recently there has been a great deal of negative talk about palm oil because of comments made in a scientific article by the IRB Barcelona. In an experiment, it seemed that cancerous cells fed on palmitic acid, which is the principal fat in palm oil, making them grow more, spread further and produce more metastasis," said Dr Emilio Ros, a researcher at the Centre for Biomedical Research in the Physiopathology Network of Obesity and Nutrition (Ciberobn).
"But there is a huge gap between that and applying it to humans and what could occur in the clinical sense. The claim may be an exaggeration but it is making people worry and think that if they buy products which contain palm oil they are going to get cancer. In Thailand, Indonesia and Malaysia people consume palm oil the same way that people in Spain consume olive oil, and there is no evidence that there is more cancer in those countries," he explained.
Finally, it also appears untrue that consuming palm oil results in obesity. "Fat in itself is not a food compound that encourages obesity," said Dr Ros. "Nowadays we know that sugars have more effect than fats. When we consume a lot of sugar our livers transform it into fat and part of that is palmitic acid because it forms part of all the cellular membranes."
So the experts discount some claims and accept others, but it has been shown that palm oil causes more damage to health than other vegetable oils. So why, then, do most items produced by the food industry contain it?
There are three reasons: firstly, palm oil is cheaper than others such as olive, corn or soya. Secondly its consistency, being more solid, is useful when making industrial bakery products; and thirdly, because of the flavour it gives the food.
"If they used more unsaturated fats like olive oil, the products would not have the same consistency; they would break up and they would taste bland," explained Dr Ros. "Palm oil is a food rich in palmitic acid, which increases cholesterol. Although palm oil is the food item which contains more of this saturated fatty acid, it is also present in others such as milk, meat and coconut oil. Although it is not recommendable to consume large amounts of palmitic acid or foods which contain palm oil, we shouldn't exaggerate about the need to restrict them, either," he said.