Text: Su Ziqian (Honorary Clinical Assistant Professor, Department of Clinical Oncology, University of Hong Kong, Chinese Medicine Physician), “Ming Pao”
(Hong Kong News) Six years ago, I wrote three articles on the relationship between cancer and sugar in “Ming Pao”, explaining in detail the origin of the saying “cancer eats sugar”. How does the patient view the issue of amyloid withdrawal.
Recently, many patients have asked the same question again. In addition, new research reports in recent years have given us a deeper understanding of how cancer cells absorb nutrients. Therefore, we will discuss this topic again: Do cancer cells only eat sugar? Don’t absorb fat and protein?
Scan tracers aren’t just “sugar water”
The most commonly injected “sugar water” during positron scanning is a special sugar “fludeoxyglucose” (FDG for short) that can release positron radiation.
After FDG enters the cells, all tissues with high metabolism (including brain, liver, kidney, and of course some cancers) will be more luminous in the report because they use a lot of sugar. But in fact, many cancers will not glow after using this FDG potion, including prostate cancer, kidney cancer, primary liver cancer, and some lung adenocarcinoma and gastric cancer.
These cancers show little luminescence if they are scanned with conventional FDG positron emission. Can we say again, these cancers can’t eat sugar?
In fact, for positron emission tomography, in addition to FDG, you can also inject other tracers (tracers) that have nothing to do with sugar to see if cancer cells have spread in the body. For example, PSMA is used for prostate cancer, and C11-Acetate is used for primary liver cancer. The doctor will choose the appropriate tracer according to the condition, otherwise the cancer cells may not be seen; sometimes more than one tracer is used, so the positron scan does not Not just using “sugar water”.
Immune cells are more able to absorb sugar
Two years ago, the top scientific journal “Nature” published a rather shocking article published by American medical scientists, confirming that cancer cells not only absorb sugar, but also absorb other nutrients.
The research team used different experimental mice and injected different positron scanning tracers to see how well each nutrient was absorbed by cancer cells.
The first thing to know is that there are not only cancer cells in a tumor, there are many immune cells surrounding it, including macrophages and various lymphocytes, trying to control and prevent the growth and spread of cancer cells (of course their efforts failed, or there would be no cancer).
Therefore, the research team wants to use the same technology to see what kind of nutrition the immune cells near the cancer cells absorb.
The research results confirm that the phenomenon of cancer sugar absorption was first proposed by German scientist Dr. Warburg 100 years ago. The study found that cancer cells do absorb more sugar than normal cells; but the experiment also proved that the immune cells surrounding cancer cells , sugar absorption capacity is much higher than cancer cells!
This can be inferred that because the immune cells are doing all they can to suppress cancer cell growth, they have a higher metabolism than cancer cells.
Starve cancer cells must break 3 nutrients
The research team then used other tracers to see if cancer cells and immune cells took up both amino acids (the building blocks of proteins) and fats.
It turns out that cancer cells absorb more amino acids (especially glutamine) and fat than normal cells, and the absorption rate is also higher than that of immune cells; this is completely understandable, because when cancer cells divide, they need Produce a large number of cell membranes. Cell membranes contain a lot of fat. Without enough fatty acids and cholesterol, cell membranes cannot be made, and cancer cells cannot grow.
In addition, because cancer cells divide rapidly, they need more intracellular proteins to handle various metabolic tasks, so it is necessary to absorb a large amount of amino acids.
A brief summary, regardless of the absorption of sugar, amino acid and fat by cancer cells,
higher than normal cells.
However, on a single-cell basis, immune cells absorb more sugar than cancer cells;
Cancer cells absorb fat and amino acids more than sugar!
The discovery 100 years ago was only to compare the sugar absorption speed of cancer cells and normal cells.
But there have been no advanced positron emission tomography scans to fully understand the nutritional metabolism of cancer.
This new study answers many things that were not clear before.
Therefore, in order to starve cancer cells to death, in theory, the three major nutrients needed by the human body, including sugar, amino acids and fats, must be quit. This obviously won’t work, because not only the immune cells will fail due to insufficient sugar, but other normal organs and the human body will also die due to malnutrition.
I often give an example to patients, although we know that cancer cells are “relatively hypoxic”, that is, the oxygen content in cancer cells is not as high as that of normal cells, but cancer cells still need oxygen to survive, will we not give patients oxygen to kill them? cancer cell? This is obviously not feasible (in fact, there is also hepatic artery embolization for the treatment of liver cancer, which is a method of locally depriving cancer cells of oxygen and nutrients).
fasting underweight adverse treatment
So how should we think about the relationship between sugar and cancer?
In an article 6 years ago, I wrote that the key is glycemic index and glycemic load, which are related to obesity and insulin resistance.
In developed societies, one-third of cancers are generally related to obesity and diabetes. In addition, studies have found that eating foods with a high glycemic index is associated with breast cancer, colorectal cancer, and prostate cancer.
So to put it simply, eating more sweets has bad effects on the body, including increased risk of diabetes, inflammation and cardiovascular disease, which are related to certain types of cancer, but it does not mean that cancer patients need to completely quit sugar or starch .
Stick to the mean and avoid extremes
In fact, the nutritional metabolism of cancer is a very profound knowledge. Different nutrients are linked together, and many myths have not been completely solved in the scientific community.
Healthy people reduce food with high glycemic index, combined with exercise, or regular fasting, which does have a positive impact on the body, but for cancer patients, because they need to receive multiple treatments, it is really necessary to avoid excessive weight loss and malnutrition.
From the perspective of Chinese medicine, it is often said that “the period of peace” means that the food and nutrition must be balanced, stick to the golden mean and avoid extremes. The Chinese character in Chinese medicine originally means “the mean”.
I hope that after reading this, readers will understand that cancer absorbs a lot of fat and amino acids, even faster than sugar. Before the patient changes his eating habits, please consult the attending doctor for safety.