Palm oil is widely used in processed foods, and whether palm oil is healthy has attracted much attention.
It has always been said that "palm oil is rich in saturated fat and is not good for health", and there have also been reports that "studies have found that palm oil promotes cancer metastasis".
What exactly is palm oil? Is there really such a big harm? Can you still eat palm oil? Let's talk about it in detail today.
01
What is palm oil?
Palm oil is a vegetable oil that is extracted from the palm fruit of the oil palm tree and has a long history of use in Africa and Southeast Asia. It and soybean oil and rapeseed oil are one of the three most used vegetable oils in the world, and have long occupied the first position [1], and the familiar peanut oil, corn oil, sunflower oil, sesame oil, etc., consumption is far lower than it.
Image credit: Pixabay, creator: Moody_Askander
Palm oil is used in food processing, daily chemicals, cosmetics and other fields [2]. A lot of people might say, "So why don't I seem to see palm oil so rarely?" It is also almost unused at home. ”
In fact, this is because you did not pay attention to the product ingredient list.
In fact, palm is everywhere around us. Many products around us contain palm oil or palm oil ingredients, such as chocolate, ice cream, instant noodles that we usually eat, and toiletries that we apply daily, such as shampoo, body lotion, sunscreen, lipstick, etc., all contain palm oil or palm oil [3].
02
What are the advantages of palm oil?
Palm oil is also widely used in food processing because it has the unique advantage of being high in saturated fat. Common vegetable oils in our lives are low in saturated fat, so they have a low melting point and are liquids at room temperature.
But palm oil is more peculiar, its saturated fat content is as high as about 50%, and lard is no less than that, followed by its monounsaturated fatty acids are also close to 40%, but polyunsaturated fat content is relatively low, which makes its melting point as high as 35 °C, at room temperature is solid or semi-solid, stability is very good, not easy to oxidize and deteriorate, taste is also better.
01
Good taste
From the perspective of molecular structure, the molecular structure of saturated fat is in a long straight line. From the perspective of food processing, when it is in contact with starch and various celluloses, fatty acids can enter the inside of the spiral structure of starch, and eventually form a stable spiral structure complex, so that the viscosity and toughness will be better, so palm oil can be hidden in food in a solid state at room temperature, unlike adding a lot of vegetable oil at room temperature will seep out [4], it brings you a delicate taste without making you feel too greasy.
02
Good thermal stability
Due to the relatively high proportion of saturated fat, palm oil is less prone to violent oxidation reaction at high temperatures, and is more suitable for high-temperature cooking such as frying, and is most widely used in fried foods [5][6][7].
Image source: Wikipedia
Such properties also make it a good alternative to hydrogenated vegetable oils in food processing. Traditional hydrogenated vegetable oil contains a lot of trans fat, everyone knows that trans fat is not good, palm oil because it does not contain trans fat and the performance is close to hydrogenated oil has been popular.
03
Does palm oil promote cancer metastasis?
However, when it comes to palm oil, many people believe that it is a cheap industrial raw material, synonymous with unhealth, and there are even reports that palm oil promotes cancer metastasis. In fact, this claim exaggerates the dangers of palm oil.
The claim that "palm oil promotes cancer metastasis", comes from a study by Spanish scientists [8].
In this study, the scientists first briefly added fatty acids to the cancer cells when growing cancer cells from human oral or skin cancer, and then transplanted these cancer cells into the corresponding tissues of mice fed a standard diet, and found that several fatty acids had no effect on the primary tumor, but palmitic acid significantly increased the ability of cancer cells to metastasize to the lungs.
Image source: Wikipedia
Another set of experiments directly fed tumor mice a diet rich in palm oil, although after only ten days, cancer cells transplanted into mice showed greater metastasis.
But this study is only an animal study, completely different from human clinical research, the experimental results are actually very rudimentary, and our usual actual diet is also very different, we don't have to worry too much.
04
What's wrong with palm oil?
The real problem with palm oil is the saturated fatty acids it contains. It may seem like a double-edged sword, from a food processing perspective, it has many advantages, but from a nutritional perspective, it is not good for cardiovascular health.
The saturated fatty acid content in palm oil is basically more than 50%, and the proportion of saturated fat in commercial (purified) palm oil can be as high as 80%. The current mainstream opinion in the scientific community is that consuming too much saturated fat increases the risk of cardiovascular disease.
For this reason, dietary guidelines and health recommendations in countries around the world remind us to limit saturated fat intake. For example, the World Health Organization, the latest dietary guidelines in the United States, and the continental dietary guidelines all recommend that saturated fatty acid intake should be less than 10% of total dietary energy.
05
Can palm oil continue to be eaten?
As an oil, palm oil also has its nutritional advantages. It can give us fatty acids and energy for human activities, in addition to containing more tocotrienols, which is a type of vitamin E; It also tends to contain more carotene, which can be converted into vitamin A in the body.
When we consider whether to eat palm oil or not, we cannot be separated from the "amount". In fact, not only palm oil, but any excessive intake of fat, even olive oil, is not good for health.
Image source: Piqsels
The "Dietary Guidelines for Chinese Residents" recommends that our total intake of edible oil be 25~30 g per day; Adult fat should account for less than 30% of the total energy, which means that the total amount of fat intake of an adult per day should be controlled at 50~70 grams. Among them, saturated fat does not exceed 10% of total fat intake, which is about 5~7 grams. Under this recommended amount, eating palm oil properly is not necessary to worry about health hazards.
But everyone needs to understand that palm oil is indeed not a healthy oil, and the use of more palm oil food, whether potato chips, biscuits, spicy strips, etc. are often high salt, high sugar, high fat, should be careful not to eat too much.
In general, palm oil itself is harmless, and foods containing palm oil are not "flood beasts", the key is to pay attention to a reasonable diet, develop healthy eating habits, and try to achieve a balanced diet.
bibliography
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[2] GAI Zhengyan, MA Chuanguo, LOU Lijuan. The latest research progress of palm oil[J].Grain and Oil Processing,2010(11):6-9.)
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[4] LI Peiyan. Effect of oil and fat on texture of fries and its mechanism[D].Jiangnan University,2021.DOI:10.27169/d.cnki.gwqgu.2021.001934.)
[5] Ji Yanyu. Study on quality change and oxidation stability of palm oil during thermal processing[D].Hainan University,2017.)
[6] KUANG Ting, JI Yanyu, YAO Mengying, YUN Yonghuan, ZHANG Weimin. Thermal oxidation stability of palm oil[J].Food Industry,2019,40(11):186-191.)
[7] Li Xu. Research on the variation law and application of polar composition of grease during heating and frying[D].Jiangnan University,2021.DOI:10.27169/d.cnki.gwqgu.2021.000063.)
[8] Gloria Pascual et al., (2021) Dietary palmitic acid promotes a prometastatic memory via Schwann cells. Nature Doi: 10.1038/s41586-021-04075-0
Planning production
Author|Ruan Quang Feng, Deputy Director of Kexin Food and Health Information Exchange Center
Audit|Han Hongwei, researcher of National Center for Food Safety Risk Assessment