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Cancer develops when the body ceases to cope with repair mechanisms, and what we eat directly affects whether the cancer will develop or not, says Iwona Sajór, a nutritionist from the Food and Nutrition Institute in Warsaw.
It is believed that 80 percent. tumors depends on environmental factors. To what extent does diet determine whether someone will get cancer or not?
Food contains a number of ingredients that have a beneficial effect on health, but it can also be a source of carcinogenic substances – initiating the process of cancer formation. A huge amount of research has been carried out on this topic in the world, and new ones are still being carried out, but only some of them provide conclusive scientific evidence. The World Cancer Research Foundation and the American Cancer Research Institute systematically review published papers and, on this basis, classify the nutritional factors studied to reduce or increase the risk of developing the disease. According to the latest report of these institutions, the direct relationship between the diet and cancers of the gastrointestinal tract, in particular of the oral cavity, pharynx, larynx, esophagus, stomach, colon, liver and pancreas, has been proven beyond any doubt. Such a relationship was also confirmed in the case of lung, endometrial and prostate neoplasms. Research on other cancers has produced less reliable evidence, so research is ongoing. In general, we know that the strongest anti-cancer effect comes from a diet rich in vegetables and fruits, and cancer is favored by frequent consumption of red meat, preserved and heavily salted foods, as well as improper heat treatment for products with high protein content, such as frying and prolonged cooking. grilling meat, sausages or fish. Cancer is also fostered by obesity and drinking too much alcohol. The evidence is less certain for many factors and therefore further research is required to confirm their protective or carcinogenic effects.
The news of cancer falls on you like a bolt from the blue, but the process of carcinogenesis is long hidden. How long?
Much depends on the type of cancer and its location, but on average it can take 10 to even 40 years from the time a carcinogen damages a healthy cell to the development of a cancer! So there is ample time to defend yourself against cancer with a proper diet. Carcinogenesis is a complex and multi-stage process.
And it starts with …
From exposure of a carcinogenic factor to a healthy cell, which works continuously for years and pierces the rock like a drop. Therefore, we probably won’t get stomach or colon cancer if we eat a grilled portion of meat several times a year, but if we do it often for years, the risk will increase significantly. Each cell is genetically programmed to defend and repair it, but if we do not help it by providing anti-cancer substances – such as vitamins and other antioxidants contained in plants, it will stop working at some point.
In a healthy organism, all processes at the cellular level are under control. Cancer is the result of losing this control. The stage at which the DNA of a healthy cell is damaged (mutated) is called initiation. Its duration is short, but it is crucial for the development or arrest of carcinogenesis. If the correct defenses are at work now, DNA can repair itself and the abnormal cell may be killed (apoptosis). However, if this does not happen, this cell, depending on the functions it performs in the body and the harmful factors that affect it, may enter the next stage of cancer formation, called promotion. It begins to live its own life, undergoes further mutations and divides without control – hence the name cancer, from the process of neoplasia. A precancerous lesion develops, such as a polyp in the large intestine, from which it may develop into a cancer, but it does not have to. Polyps are removed by endoscopy of the large intestine (colonoscopy) to prevent them from growing. Changing your diet to a healthier one at both of these stages can slow down or even inhibit the process of carcinogenesis.
What ingredients of our menu protect against carcinogenesis or promote its stimulation? I am asking for examples proven beyond doubt about the digestive system?
The digestive tract is lined with delicate mucosa, and everything we eat affects this membrane – positively or negatively. Inaccurately chewed pieces of food or too high temperature of food and drinks can irritate it and damage it mechanically, which increases the risk of harmful ingredients from food penetrating the mucosa. By eating vegetables and fruits, we provide antioxidant substances to combat free oxygen radicals constantly formed in the body during respiration, metabolic processes and cell aging. The body systematically neutralizes them, thus preventing them from entering into biochemical reactions that would cause DNA damage and disturb the proper processes of cell division, which, as we know, lies at the basis of carcinogenesis. Low-starch vegetables, i.e. all except potatoes and boiled carrots and beets, have the greatest protection in the case of cancers of the digestive tract (mouth, throat, larynx, esophagus, stomach), because they are rich in antioxidant vitamins C, A, E, carotenoids, folic acid , polyphenols. These compounds react directly with free radicals, resulting in the formation of less harmful radical forms. Vitamins also prevent the oxidation of phospholipids that are part of cell membranes, and thus reduce the formation of free radicals. Some ingredients in food, incl. selenium, copper, zinc, manganese are also part of enzymes, incl. catalase, glutathione peroxidase, superoxide dismutase, which directly scavenge free radicals.
From the esophagus we go down to the stomach.
Here, as a first-class carcinogen, the leader is the bacterium Helicobacter pylori, which has as much as 84 percent in its stomach. adult Poles. But take it easy, in most infected people, this bacterium will cause a little inflammation in the lining of the digestive tract, but it is no worse than heartburn. There are also, unfortunately, more virulent strains that sometimes even antibiotics cannot cope with. Then, as a result of chronic inflammation, changes occur in the gastric or duodenal mucosa, and this promotes the formation of erosions, ulcers – which penetrate the mucosa, cause bleeding, and sometimes rupture. Such mucosal lesions increase the risk of developing gastric cancer. A harmful factor supplied with the diet is salt, the excessive consumption of which accelerates the carcinogenesis process initiated by Helicobacter pylori. The point is not to not use salt at all, but to limit its amount in the diet, avoiding adding salt to food and consuming products containing significant amounts of it. Nitro compounds, nitrates and nitrites have a similar carcinogenic effect.
In what products are they present?
In preserved foods, especially in cured, heavily salted or smoked meat, cold cuts, cheese. And again, it is about moderation: if we eat canned smoked meat or fish from time to time, nothing will happen, but regular consumption of such products is risky, especially for people with a family history of stomach cancer. Nitrate preservatives are one of the most important factors accelerating the process of carcinogenesis in the stomach. If the lover of eating such products will avoid vegetables and fruits containing vitamin C, then the cancer process can proceed without any problems at this point.
Stomach cancer a few decades ago took an incomparably higher toll among Poles than today. What contributed to the decline in its occurrence?
This is related to the popularization of refrigerators and refrigerators in the 70s and 80s, which facilitated the storage of food, especially meat and fish, without the need to use as much salt for preservation as before. In addition to reducing salt intake, Poles began to eat more fruit and vegetables. Seasonality and the availability of fresh fruit and vegetables is also not as much of a limitation as it used to be. Now these products are available virtually all year round, because we can store them better (e.g. freeze), and we have imported varieties. You can look for a hole in it by pointing out to those imported that they are picked unripe, treated with anti-mold substances, etc., and yet there are more health benefits from consuming them than excluding them from the off-season diet. It’s like fish, we can say that they are contaminated with heavy metals, but research shows unequivocally that it is better to eat them than not eat them completely.
As we are already with the fish. What’s wrong with smoking?
During the smoking of products with a high content of animal protein, i.e. fish, meats, and cold cuts, heterocyclic amines and polycyclic aromatic hydrocarbons are formed, substances with carcinogenic effects, similar to nitrosamines. Their frequent consumption promotes colon cancer. So it is better to choose fresh fish, and smoked fish is enough when they reach the table once a month. Eating them every day or several times a week for many years is definitely bad for the body. These harmful compounds are formed not only during smoking, but also during prolonged grilling or frying meat and fish at high temperatures. These crunchy, browned, burnt products, which are what everyone tastes like that, is the source of carcinogenic compounds.
How do you tell Poles when the barbecue season is in full swing?
It’s all about moderation. If we eat grilled meat or fish two or three times a season, and at the same time with a large portion of vegetables (antioxidants!), The body will be fine. But again – not every weekend. When grilling, put the meat on special trays or wrapped in aluminum foil, because it limits direct contact with the smoke. The meat can also be marinated or pre-boiled in advance, thanks to which we will shorten the grilling time. It is also better to grill, if at all, in a special pan designed for this purpose. Provided that the meat or sausages placed there are not charred, because we will “enrich” them with the carcinogenic hydrocarbons mentioned above. Before baking in the fire, also wrap the potatoes in aluminum foil, which will cut off the direct effect of the smoke.
So grilled vegetables are better, because they have no protein.
Yes, but when it comes to vegetables, the essence is that they lose a lot of vitamins under the influence of high temperatures. Vegetables and fruit are best eaten raw.
Let’s move on to the large intestine.
Here, an extremely important role is played by fiber (dietary fiber), contained in vegetables and fruits, as well as in whole grains and legumes – such as beans, lentils, soybeans, chickpeas and peas. A diet rich in fiber needs adequate hydration in order to fulfill its role of preventing constipation. In people who avoid fiber or drink too little fluid, fecal masses accumulate and remain in the large intestine. Compacted and dried, they cannot get out of there because there is no driving force to remove them. The intestinal peristalsis alone is not enough here. Fiber acts as a scrub brush that facilitates regular bowel movements. If we drink a lot, fiber increases the volume of the stool mass, which acts as a stimulant for the intestines – undigested food debris more easily moves lower and lower until the bowel movement. The stool contains unnecessary metabolic products (including secondary bile acids, formed as a result of cholesterol metabolism), the high concentration of which in the large intestine has a carcinogenic effect. For this reason, it is very important to get rid of them as quickly as possible, reducing the time they come into contact with the intestinal mucosa. A diet rich in fiber also promotes the development of a beneficial intestinal microflora, i.e. it plays a prebiotic role.
And what does bile acids do to the colon?
In high concentrations, they may be mutagenic in relation to the intestinal mucosa. They irritate its walls, which promotes inflammation, and chronic inflammation is a step towards the development of the neoplastic process.
Why is inflammation promoting cancer?
I’ll explain what the inflammatory process is. We deal with it when a cell is affected by some harmful factor, e.g. the mentioned bacteria in the stomach, and the body tries to get rid of it. For this purpose, it stimulates the immune system, which produces cytokines – anti-inflammatory substances, including interleukins, TNF-α. Cytokines are proteins, so the body has to spend a lot of energy to produce them, and it draws it first from food, then from adipose tissue, and when these reserves run out, then from muscle tissue. Not all infections are dealt with quickly, so it’s not uncommon for your body to produce these anti-inflammatory proteins over a long period of time. And such chronic inflammation is a revolution in the body, it changes metabolism, has an impact on the hormonal balance, as a result, many changes occur in the body, and the disturbance of normal processes may be the beginning of carcinogenesis. In the case of obesity, there is also minimal chronic inflammation, although the mechanism of its formation and effects have not yet been fully explained. It is known, however, that any excess kilograms are dangerous, because all organs have to work harder, not only the joints, but also the liver, kidneys and lungs. The greater the overweight or obesity, the greater the risk of developing cancer.
I understand that vegetables and fruits, along with the antioxidants they contain, are needed to stop the inflammatory process?
Just like that. Polyphenols (lycopene, resveratrol), catotenoids, vitamins and a number of other bioactive substances. In the case of protecting the stomach against cancer, organosulfur compounds present in garlic and onions, which are powerful antioxidants, have proven effects, in addition to fruits and vegetables.
And what do we know about the liver in the context of diet-related cancers?
This organ collects all the toxins from all over the body that it has to deal with. The more harmful substances it has to metabolize, the worse it is for it. I personally feel sorry for the liver. Aflatoxins produced by molds that develop mainly on poorly stored cereal seeds, nuts and legume seeds are particularly harmful to it.
People often remove the mold and eat the rest.
Exactly! This is tricky because the toxins produced by the mold are invisible. When the food becomes moldy, we throw it in the trash in its entirety. And nothing here will be done by the action of high temperature – it will destroy the mold, but not the toxins. And when it comes to dry legumes or nuts, it is better to buy them in sealed packages than by weight. We will help the liver by not adding work to it. It is also worth remembering that this organ does not like alcohol in particular.
What about wine, which is rich in polyphenols?
Be careful with alcohol. WHO has defined threshold values that are unlikely to harm a man – for a woman it is one and for a man two drinks or glasses of wine a day. Only that it applies to the general population, and man is an individual. The recommendations clearly state that if someone is at risk of cancer, especially hormone-dependent cancer such as breast, uterine, ovarian or prostate cancer (in men), then these people should not consume alcohol at all, because in them this toxic effect is even stronger . It is documented. Fortunately, the same beneficial ingredients as in wine can also be found in grapes.
What does alcohol have to do with ovarian or breast cancer?
The body must metabolize it, just like any other component of the diet, and during the metabolism of alcohol, a particularly large number of free radicals are formed, as well as many toxic substances that initiate damage to DNA. If we drink alcohol often and a lot, the body may not be able to repair the damage and carcinogenesis will progress. Alcohol is also associated with increasing estrogen levels. Anyway, you have to be especially careful with alcohol, especially in our country, because Poles think like this: if a glass of wine will help me, how much will a whole bottle help!
Why in the case of neoplasms of other organs, apart from the gastrointestinal tract, e.g. the breast or the uterus, there is no such compelling evidence of a direct protective effect of dietary components?
Food and the digestive tract are inherently related and the influence of these factors is likely to be more direct compared to the effects on the breast or uterus. At the laboratory level, we can subject any cell to various factors and check how they affect it. However, the results cannot be applied to the whole organism, which is a combine, with individual characteristics, and is also influenced by other factors, such as environmental. European and American women develop breast cancer. But when they migrate from Asia to Europe or the USA and settle there permanently, they suffer from cancer of this organ as often as native inhabitants of these regions. But whether soy itself works against cancer or a large amount of plant products in the diet in general, or maybe both together – we do not know yet. But research continues. So we know that diet has an impact on this type of cancer as well, but we still do not have direct causal data. While waiting for the next test results, it is worth sticking to the principle of keeping the body in balance, i.e. homeostasis. Every day we are bombarded with carcinogens from the environment and food, so if we know that antioxidants help to deal with them, we should not feel sorry for them on our plates.
She talked: Agnieszka Fedorczyk