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Nature: Palmitic acid promotes the metastasis of cancer cells!
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Nature: Palmitic acid promotes the metastasis of cancer cells! You may eat it everyday.
Palmitic acid (PA) is the most common saturated fatty acid in the human body, accounting for 20-30% of the total fatty acids in the human body.
On average, a 70 kg person is composed of 3.5 kg palmitic acid. It can be provided by diet or synthesized in the body.
Palmitic acid is widely present in our usual diet.
Palmic acid accounts for 44% of palm oil’s total fat. Because palm oil contains no genetically modified ingredients, its oil output per unit area is 10 times higher than other oilseed crops.
It has surpassed soybean oil to become the most important edible vegetable oil in the world.
Palm oil is widely used in the food processing industry: candy, cakes, cheese analogs, potato chips, chocolate, biscuits, frozen foods (pancakes, pies, pizza), ice cream, instant noodles and oatmeal, margarine, peanut butter, salad dressing, Hot pot bottom materials and so on.
In addition, palmitic acid is also present in many meats and dairy products (accounting for 50-60% of total fat), cocoa butter (accounting for 26% of total fat) and olive oil (accounting for 8-20% of total fat) , Even in breast milk (20-30% of total fat).
For a long time, there has been no conclusion on whether palmitic acid is harmful to health.
A report of the World Health Organization (WHO 2003) indicated that palmitic acid would increase the risk of cardiovascular disease, but other experimental results did not support this conclusion.
The controversy of the results may be due to the complexity of diet, experimental selection criteria and experimental subjects The age and other differences.
A recent article published in “Nature” showed that palmitic acid changes the epigenome of mice and promotes the metastasis of mouse cancer cells.
Researchers used 300μM palmitic acid (PA), 50μM oleic acid (OA) or 50μM linoleic acid (LA) to stimulate human oral squamous cell carcinoma (OSCC) cells in vitro for 4 days, and then these cells In situ inoculation into mice on a standard diet.
It was found that mice vaccinated with palmitic acid-stimulated OSCC cancer cells had a significant increase in the number and size of metastatic lesions, but oleic acid and linoleic acid had no such effect.
Not only that, the researchers also found that this transfer enhancement does not require the continuous stimulation of palmitic acid .
Researchers used palmitic acid to stimulate OSCC cancer cells in vitro for 4 days, then cultured the stimulated cancer cells in standard culture medium for 14 days, and found that the cancer cells still have a high metastatic ability!
It shows that the short-term stimulation of palmitic acid can maintain the strong metastasis ability of cancer cells for a long time.
So, will foods containing palmitic acid also promote cancer cell metastasis?
Next, they inoculated OSCC cancer cells into mice in situ and after the primary tumors formed, they fed these cancer-affected mice a short-term diet rich in palm oil, and fed a diet rich in olive oil or a standard diet. The cancer-bearing mice were used as controls.
After 10 days, they all changed to a standard diet.
In order to observe the results of metastasis more clearly, they took out primary tumors from mice and purified them, and then transplanted these purified cancer cells into secondary mice fed a normal diet.
It was found that the metastasis ability of tumor cells from primary mice in secondary mice was stronger than those fed with olive oil and standard diets.
It shows that foods containing palmitic acid can also promote the metastasis of cancer cells.
Cell behavior is controlled by gene expression. So, has the epigenome of cancer cells stimulated by palmitic acid changed, leading to changes in gene expression?
Researchers analyzed the epigenome of OSCC cancer cells treated with palmitic acid in vitro, and found that H3K4me3 has undergone stable changes, and therefore mediates expression of tumor cells that are related to neurogenesis, neural remodeling, and tumor extracellular matrix (ECM).
Genes such as tissue and glial production have been shown to be related to poor prognosis of cancer.
H3K4me3 is a trimethylation marker of the fourth lysine residue of histone H3, and it is mainly responsible for gene initiation.
Marks such as histone modification such as methylation and acetylation can be inherited to offspring.
Therefore, the H3K4me3 changes caused by palmitic acid treatment can be passed on to its progeny cells as the cancer cell divides.
This is why cancer cells still have a strong ability to metastasize after stopping palmitic acid stimulation.
All in all, this study confirmed that dietary palmitic acid can not only promote the metastasis of cancer cells, but also pass this metastatic ability to their offspring, so that this strong metastatic ability can be maintained for a long time.
Seeing this, many people may want to throw away processed foods containing palm oil, such as instant noodles, hot pot bottoms, etc.
It is certainly true to eat less processed foods, but even if we don’t eat palm oil, we drink milk and meat every day. A lot of palmitic acid, will this affect our health?
Fatty acids (such as palmitic acid) are an important part of the diet and participate in many key physiological activities in the human body: ensuring the physical properties of cell membranes, palmitoylation with proteins, palmitoylethanolamide (PEA) biosynthesis, and effective surface activity in the lungs Agent activity and so on.
Under normal circumstances, the content of palmitic acid in the body tissues seems to be controlled near a clear concentration.
According to literature reports, the average daily intake of palmitic acid by the human body is about 20-30 g, and its intake will not change.
Obviously affect its tissue concentration, because dietary palmitic acid will balance with palmitic acid biosynthesis (DNL) in the body to maintain a steady state of tissue concentration.
Image source: https://doi.org/10.3389/fphys.2017.00902
However, under some specific factors, such as excessive intake of carbohydrates (especially monosaccharides and disaccharides) and a sedentary lifestyle, the tissues may over-accumulate palmitic acid, which may cause dyslipidemia, hyperglycemia, Ectopic fat accumulation increases; or under certain pathological conditions, palmitic acid may further accelerate the harmful effects on the body.
Just as in the above-mentioned “Nature” study, palmitic acid does not cause cancer in mice, but in the case of mice suffering from cancer, it will accelerate the metastasis of cancer cells.
Therefore, it is not enough to go through everything. A balanced diet and good living habits are conclusively proven to be beneficial to health !
Salvador Benitah, Dietary palmitic acid promotes a prometastatic memory via Schwann cells, Nature (2021). DOI: 10.1038/s41586-021-04075-0. www.nature.com/articles/s41586-021-04075-0
Nature: Palmitic acid promotes the metastasis of cancer cells!
(source:internet, reference only)