After a cancer diagnosis, it is common to search for information on what foods can help fight the disease. Products, cooking methods, utensils, diets… that could be harmful or that could have a miraculous effect on the body. All this information from websites, books, magazines and even advice from friends or relatives who have heard or read about the subject, can generate a feeling of information overload and with it a feeling of anxiety, not knowing what is true and what is not. In some cases, people end up eliminating from their diet foods that are essential for dealing with the disease or, on the contrary, adding foods, herbs or supplements that may be harmful or that simply increase the cost of the diet without any real evidence of their effectiveness.
This section collects and analyses some of the most common myths and legends related to food and cancer treatment, explaining whether they are well-founded or have no firm scientific basis to support them. For the elaboration of this section a bibliographic review of scientific studies published in recent years, the declarations of existing official food safety bodies, both national and international, such as the ACSA (Catalan Food Safety Agency), the AECOSAN (Spanish Agency for Consumer Affairs, Food Safety and Nutrition of the Spanish Ministry of Health); the EFSA (European Food Safety Agency); the FDA (United States Food and Drug Administration), and the WHO (World Health Organisation) have been taken into account. The recommendations of different institutes, societies and associations specialised in research and dissemination of information on cancer prevention and treatment have also been considered for this section.
It is not recommended to consume any type of dietary supplements without them being prescribed by your medical team or your designated dietitian/nutritionist.
The existence of a wide variety of products with dietary purposes often leads to confusion between dietary supplements containing vitamins, minerals, antioxidants, and other bioactive compounds that can be purchased without a prescription at health food stores, pharmacies…and nutritional supplementation with medical nutrition products. The belief in the beneficial effects of the former (antioxidant supplements or those based on other compounds) is highly popular among many individuals undergoing cancer treatment due to the numerous messages circulating about their 'miraculous' properties, despite lacking scientific evidence to support them.
Adequate nutritional status is essential to cope with the disease and its treatments. In the market, there are many supplements with varying compositions and qualities some harmless and safe, but others not. Therefore, incorporating additional vitamins, minerals, antioxidants, or other bioactive compounds through the consumption of dietary supplements can cause serious and harmful side effects, as they may interact or interfere with ongoing treatments, reducing their effectiveness or causing unexpected severe toxicities. Hence, it is essential to always consult with the medical team before incorporating such a supplement into the diet. On the other hand, when nutritional needs cannot be met through regular food intake, the oncologist may prescribe nutritional supplementation with products designed for special dietary needs. These products are specially formulated and developed for the nutritional treatment of patients under medical supervision, thus forming an integral part of the treatment and should be completely distinguished from the aforementioned supplements.
Despite the growing research on the use of dietary supplements during cancer treatment, the current evidence is insufficient. There is currently no scientific evidence supporting the use of antioxidants, additional vitamins, or minerals to help treat or cure cancer. Some cancer treatments may include specific doses of certain vitamins or minerals, but your medical team will make these additional prescriptions. On the other hand, nutritional supplements are products for special medical purposes supported by scientific evidence regarding their effectiveness, safety, and efficiency in addressing the nutritional needs of individuals requiring them due to their nutritional status. Nutritional supplementation can be recommended as a complement to food intake or as a complete liquid diet orally. A prior nutritional assessment should be conducted to select the most suitable product. There are various types of nutritional supplements to meet different needs, available in different flavors and textures. These supplements may be funded by the National Health System based on regulated criteria and can only be obtained from pharmacies or through hospital channels.
You do not have to eliminate red meat from your diet during cancer treatment, but it is recommended to consume moderately and limit the consumption of processed meat. However, its consumption is entirely optional.
Meat is a very misconceived product. It has a bad reputation because high red meat consumption is associated with an increased risk of developing some types of cancer, especially colorectal cancer. This information has reached the false conclusion that any consumption of red meat during cancer treatment is harmful.
During treatment and subsequent recovery, eating red meat is not harmful, as protein intake is essential for tissue repair and regeneration. The recommended consumption of meat is three or four servings a week (100-125 g/serving), of which two can be red meat, prioritising the leanest parts, removing visible fat and limiting its intake when the meat is processed.
The working group from the International Agency for Research on Cancer (IARC) concluded that there is an association between high red and processed meat consumption and the development of colorectal cancer, classifying processed meats as a carcinogen and red meat as a probable carcinogen. As a result, the World Cancer Research Fund International (WCRF) recommended limiting red meat consumption to less than 500g per week and consuming as little processed meat as possible (WCRF, 2018). Nevertheless, there is no consensus linking moderate consumption with the risk of cancer development or interaction during treatment. Meat, and red meat, in particular, is an excellent high-quality source of protein, zinc, iron, B vitamins and vitamin K.
The experts’ recommendation is to follow a healthy, balanced diet that includes daily consumption of dairy products. Dairy products should only be eliminated from your diet if your oncologist or your registered dietitian indicates so.
That the consumption of dairy products has a negative effect on people undergoing cancer treatment is another of the most common myths. This may be due to the false link between breast cancer and the type of fat contained in milk products. The fat in dairy products, which is mostly saturated, has always had a bad reputation.
During cancer treatment experts recommend following a healthy and balanced diet that includes daily consumption of dairy products (two or three servings a day), because of the nutrients they provide: proteins, vitamins, and minerals. Each person can consult their specialist about the most suitable version for their needs (whole milk, semi-skimmed or skimmed milk). In case of lactose intolerance, it is recommended to test the tolerance to fermented dairy products such as yogurt and cheese or use lactose-free dairy products. Soy, oat, rice, or almond milk are not nutritionally equivalent.
Current scientific evidence indicates that the adequate intake of dairy products such as milk, yoghurt and cheese is not associated with an increased risk of developing cancer, nor does it have a negative effect on treatment. Recent studies have shown that some components of milk, such as calcium, vitamin D, and lactoferrin, may have an anticarcinogenic effect and reduce the risk of certain types of cancer, such as breast or colon cancer, although further studies are needed to confirm these findings.
Eating sugar or foods containing different types of sugars, especially from fruit, vegetables, and cereals, in moderation and as part of a balanced diet, has no harmful effects on health.
Some sources have taken the results of studies revealing the effect of sugar on tumour cell growth out of context. This has led to the complete elimination of all sugars and sugar derivatives from the diet of many cancer patients for fear of ‘feeding’ the cancer cells.
Sugar is an essential nutrient and belongs to the group of carbohydrates, and they can be simple or complex. Simple sugars include refined sugar, pastries, and sugary drinks, and should be avoided. Nevertheless, simple sugars that come from fruit, or complex sugars coming from cereal, pasta or bread are highly recommended during cancer treatment because they produce energy and help the body function properly. Carbohydrates are part of a balanced diet and help to maintain an adequate nutritional state during cancer treatment. In the Mediterranean diet, 50-60% of daily energy should come from this food source.
In recent years, numerous authors have studied the effect of glucose on the replication of tumour cells, and some have evaluated the role of calorie restriction on tumour cells and molecular biology both in vitro and in vivo in animals. Such restrictions may have unintended consequences in patients undergoing cancer treatment, such as malnutrition, muscle loss and significant nutritional deficiencies, which may jeopardise the efficacy of cancer treatment. Therefore, current evidence in humans discourages the complete dietary carbohydrate restriction, even simple or complex, during treatment and encourages a balanced diet with sufficient energy and protein intake.
A moderate consumption of chocolate has no negative effect on the health of patients undergoing cancer treatment. Chocolate, preferably dark or high in cocoa (minimum 70%), can be included in a balanced diet, in moderate quantities.
The origin of the myth, which has led some people to eliminate chocolate from their diet altogether, may lie in the fact that a lot of chocolate-based foods are relatively high in sugars and/or fats, and therefore in calories. High consumption of these products can contribute to weight gain and obesity, factors that can increase the risk of some diseases, including cancer.
We can include chocolate consumption as part of a healthy and balanced diet. Scientific evidence justifies a moderate consumption of dark chocolate (>70% cocoa), two or three times a week without exceeding 50 g per week.
There is no scientific evidence that links a moderate consumption of chocolate with an increased risk of developing cancer or interaction with cancer treatment. In recent years, the possible health benefits of consuming dark chocolate (>70% cocoa) have been studied due to its high content of polyphenols (with high antioxidant power) and other bioactive compounds, with benefits observed in the cardiovascular and nervous systems.
The consumption of artificial sweeteners available in the market is considered safe within the Acceptable Daily Intake (ADI). Nevertheless, experts are increasingly advising to restrict their consumption due to the lack of nutritional benefits they offer. Furthermore, they are often associated with highly processed products, the excessive consumption of which is linked to health issues.
In recent decades, various claims have linked the consumption of artificial sweeteners to different adverse health effects, including a potential association with cancer. Some media have disseminated anecdotal reports or news publications that create confusion regarding the safety of sweeteners and the actual existing evidence.
People undergoing cancer treatment can safely consume sweeteners or foods containing them, always within the context of a balanced diet and in moderate quantities. Nevertheless, the World Health Organization (WHO) advises against their consumption for the general population, only justifying their use in people diagnosed with diabetes, where artificial sweeteners can replace sugars that have a greater impact on blood sugar levels.
Artificial sweeteners or low-calorie sweeteners (such as acesulfame K, aspartame, saccharin...) are ingredients that are 150 to 600 times sweeter than sugar and have minimal to zero calories. They are used to sweeten foods and also serve as food additives, especially in products and diets for people with diabetes, low-calorie diets, etc. The European Food Safety Authority (EFSA) regularly reviews their safety, and the E number indicates that the product has been approved and is safe for human consumption. Organizations like the International Agency for Research on Cancer (IARC) and the Joint FAO/WHO Expert Committee on Food Additives (JECFA) also supplement these reviews and have recently published their assessments on the effects of aspartame. Currently, there is only limited evidence in the case of excessive aspartame consumption, with it being classified as possibly carcinogenic to humans, specifically for a type of liver cancer. The same publication has also reaffirmed that consuming an amount within the acceptable daily intake is harmless, with no need to modify its value, limited to 40 mg/kg of body weight. Regarding other artificial sweeteners, there is no evidence suggesting an association with cancer development or interaction during treatment.
Under no circumstances. Tap water (provided it is stipulated as drinking water) can be used for human consumption, both for cooking and drinking.
Some sources of information suggest that patients should not drink tap water during treatment as some of its components (fluoride, chlorine) can be harmful. The origin of this belief may have emerged from studies published in the 1990s on the development of bone cancer in rats that were given fluoridated water. In addition, there is a popular belief that tap water is not good to drink because it is not known where it comes from, how it is transported or what materials the pipes are made of.
Drinking water is essential, especially for people undergoing cancer treatment. It is necessary to keep the body's cells well hydrated so that they can better withstand the treatment. Patients should drink two litres of water (about eight glasses) daily. If you drink tap water regularly, you can continue to do so safely during cancer treatment.
There is no scientific evidence that proves any connection between the consumption of fluoridated water and the development of cancer or a detrimental effect on cancer treatment. Water fluoridation is a public health measure to help prevent tooth decay, but this is not used in tap water in Spain. Chlorine is added to water to disinfect it from microbial agents that could be harmful to our health. The World Health Organisation (WHO) brings together groups of scientists to evaluate health criteria to ensure the safety of water for public consumption.
Yes. Fish (both white and oily varieties) and seafood are essential in a balanced and varied diet. They are an excellent source of proteins, minerals, vitamins from group B (B6 and B12) and vitamins A, D, E, and the best food source of omega-3 fatty acids.
The origin of the myth comes from the apparent mercury content in oily fish and the health risks associated with its consumption. Some sources advocate its negative effect during cancer treatment and therefore promote the total elimination of oily fish from the diet.
Fish is an essential food and must be a regular part of the diet of people undergoing cancer treatment due to its multiple benefits. Patients should eat fish three to four times a week, where one or two of the times it should be oily fish (sardines, mackerel, anchovies, salmon, etc.).
Today, evidence shows that omega-3 fatty acids in oily fish have a positive effect during the treatment and prevention of some types of tumours. Mercury is an element that can bioaccumulate in some long-lived predatory species such as tuna, swordfish, groupers, or shark. Both the European Food Safety Authority (EFSA) and the Spanish Agency for Food Safety and Nutrition advise the consumption of oily fish occasionally and recommend avoiding it in pregnant and breastfeeding women and children from 1 to 30 months. Small oily fish (sardines, anchovies, mackerel, etc.) and white fish do not accumulate methylmercury and can therefore be eaten regularly as part of a balanced diet.
Food-grade containers approved by the European Union, when used properly (single-use containers should not be reused, and they should not be microwaved unless specifically indicated as microwave-safe), are safe during cancer treatment.
Some sources link the use of plastic containers (containing bisphenol A or BPA) to an increased risk of certain types of cancer, such as breast or prostate cancer, as well as other diseases. This is due to the potential migration of small amounts of BPA into the food, which can interfere with hormonal balance
The whole population, both for sustainability and healthy reasons, should reduce the use of single-use plastics and consequently limit the consumption of foods and beverages wrapped or coated in plastic. Some cancer research institutes recommend restricting the use of products containing BPA in breast cancer and other hormone-dependent tumors. This recommendation does not contraindicate the use of food-grade plastic containers, provided they are used correctly. It is recommendable to prioritize glass containers for both storing and preserving food at home and for reheating food in the microwave. Additionally, materials in contact with food should be manufactured in compliance with EU regulations to ensure that any potential transfer to the food does not pose safety issues or have adverse effects on the food.
Chemicals like BPA used in food containers can migrate in very small amounts into the food and beverage they contain, with limited evidence suggesting potential adverse effects on the immune system. Facing these risks and the difficulty of estimating the level of exposure to these components, the European Food Safety Authority (EFSA) recently published the results of its reevaluation of the health risk posed by the presence of BPA in food. This includes a significant reduction in the TDI (tolerable daily intake) to 0.2 nanograms per kilogram of body weight per day, as a public health strategy. They also warn that all individuals across all age and groups with average and high exposure to BPA are exceeding this intake, indicating a health issue due to dietary exposure to BPA. Therefore, authorities are implementing protective measures for the population, such as the new Waste Law, which prohibits the use of BPA, to ensure the safety of packaging and compliance with the new EFSA recommendations.
No. Teflon and all other commercially available materials suitable for cooking are safe and adequate for people during cancer treatment.
Some sources claim that non-stick cookware, a material better known as Teflon, has harmful health effects and recommend the exclusive use of pots and pans made from porcelain. The origin of this myth may lie in the fact that the fumes released from a non-stick frying pan if overheated to very high temperatures (350-650 °C) could be toxic if inhaled. These temperatures, however, are never reached in domestic kitchens.
There is no justification for the use of porcelain utensils as the only safe material for cooking during cancer treatment. Any commercially available material can be used safely. Nevertheless, it is recommended, not only for people affected by cancer but for the whole population, that utensils that are in contact with food should be of good quality, suitable for cooking and in good condition, without scratches or any other damage.
There is no confirmed scientific evidence that proves the materials used in cooking (silicone, plastics, ceramics, enamel, glass, stainless steel, iron, non-stick copper, and aluminium) have harmful effects on health, can cause cancer, or interfere with treatment, provided they are used according to the manufacturer's recommendations. Regarding Teflon, the International Agency for Research on Cancer (IARC) specifies that there is no evidence to classify Teflon tetrafluoroethylene as a carcinogen, so using materials containing Teflon does not pose a health risk. It could pose a risk if utensils are overheated to temperatures above 350 °C, which is not reached in domestic kitchens and would burn the food, which could not be consumed.
The use of a microwave oven does not present any risk to health. The health authorities have been guaranteeing its safety for years and it can be used daily to heat and cook food with complete peace of mind.
There are many myths surrounding microwaves and their effects on health, especially regarding their use causing the onset of cancer. The origin of these myths comes from the misinterpretation of the effects the radiation that these appliances use to heat or cook food has on people.
Always use microwave-safe containers and do not exceed the re commended cooking times so as not to overheat the food. Microwaves can be used for both heating and cooking food, representing a cooking method that has advantages over traditional systems: it minimises cooking time, is clean and preserves the nutrients of the food in a slightly higher proportion than other cooking methods.
Microwave cooking does not change the chemical composition of the food and does not emit ionising radiation. The appliance generates waves that interact with the polar molecules of food (mainly water) generating movement, and it is the collisions with adjacent molecules that produce the heat that cooks the food. The safety of microwave waves is endorsed by both the World Health Organisation and the US Food and Drug Administration (FDA), and their alleged link to cancer was disproved in 2004 by the Spanish Association Against Cancer.
Some compounds found in grilled foods may be carcinogenic, but there is no evidence linking this effect to occasional consumption.
There is much controversy and discussion about the consumption of grilled or barbecued foods being associated with an increased risk of developing cancer. Some sources suggest that any food cooked with these techniques should be directly removed from the diet.
There is currently no specific indication as to how often these foods should be consumed during cancer treatment. Therefore, the recommendation would be the same as for the rest of the population: the occasional use of this type of cooking technique, leave a good enough distance between the grill and the food to avoid burning, and always remove the blackest parts before eating. Marinate meat with antioxidant compounds such as garlic, ginger, pepper, and onion will help to protect the food and reduce the formation of carcinogenic compounds.
Polycyclic aromatic hydrocarbons (PAHs) and heterocyclic amines (HCAs) are compounds found in grilled foods (fish and meat) or some smoked foods. Some studies have shown that they may cause changes in DNA and thus be carcinogenic: some PAHs have been classified as probable carcinogens in humans by the International Agency for Research on Cancer (IARC) such as benzo[a]pyrene. In addition, exposure to high levels of HCAs may cause cancer in animals (the connection in humans being unclear). Nevertheless, there is not enough evidence to link occasional consumption with a harmful effect when treating cancer.
This is not necessary. Buying organic food is a personal choice and not a medical recommendation. Because of the extensive regulatory framework, both organic and conventional food can be consumed reliably.
Many unsupported sources recommend a "natural" or exclusively organic diet for people affected by cancer to avoid pesticide or antibiotic residues that may be contained in some conventional foods.
Consuming food produced more sustainably is beneficial for the sustainability of the planet, especially if it is local. It is recommended, whatever the choice: to buy from trusted, quality establishments, to consume local and seasonal products, and to wash fruit and vegetables thoroughly before eating. Buying organic food is, therefore, a personal choice and not a recommendation. It should be noted that not all organic food will be good, as some contain high proportions of saturated fats, sugars...
Although some studies indicate that there are higher concentrations of some health-promoting components in organic products, the claim that they are nutritionally or biologically better is not compatible with the current scientific evidence, which, to date, has not shown them to be safer or more nutritious than conventional foods. Regarding the effects of eating organic or conventional food on cancer prevention or treatment, some studies link the consumption of organic food to a lower risk of cancer, but more studies are needed to establish a concrete conclusion and recommendation.
Garlic and its close relatives such as onion, leek, or chives, contain substances that may have some beneficial properties against cancer according to laboratory tests, but their effect on humans has not yet been confirmed.
Garlic has been used since ancient times to treat various conditions due to its antiseptic, fungicidal, bactericidal, purifying, diuretic, and circulation-improving properties. The beneficial properties of garlic are so many that there have even been claims it has anti-cancer properties, taking results of observational or laboratory studies out of context, and which do not provide accurate and reliable information to clarify whether garlic consumption can in fact have beneficial effects during cancer treatment.
Garlic is a common ingredient in our culinary culture, commonly consumed and fully recommended as part of a balanced diet. The World Health Organisation (WHO) recommends a consumption of fresh garlic for adults of 2-5 grams/day (1 or 2 cloves of garlic) for its beneficial properties on the vascular system. Excessive consumption may cause side effects such as bad breath, strong body odours, heartburn, nausea, or vomiting. Similarly, high amounts or extracts should be avoided before and after any surgery, as they may increase the risk of bleeding. Therefore, its consumption is optional and always used as an ingredient in the kitchen.
Laboratory tests have shown that garlic and other vegetables in the same family contain allicin and polyphenols, such as quercetin, which may protect the cell from cancer-triggering substances, reduce cell proliferation or induce cell death in cancer cells. Although these observations show that garlic consumption may reduce the risk of cancer, there is currently not enough scientific evidence to recommend garlic as a food to help treat cancer, given that there are no human clinical studies to confirm this.
The consumption of berries is perfectly safe, but the fact that some health effects have been scientifically proven does not imply that they can cure cancer if consumed regularly or excessively.
The recommendation to consume berries, both to prevent and cure cancer, is widely spread and is one of the most recurrent pieces of advice when talking about nutrition and cancer prevention or treatment.
Including berries as part of our diet is completely safe in and healthy due to its antioxidant properties. The recommended fruit intake during treatment indicates three pieces or portions of fresh fruit (including berries) daily and as varied as possible, as each fruit has different properties that are beneficial to our health. The best way to take advantage of the properties of fruit is to consume local and seasonal fruit.
Berries (raspberries, blueberries, blackberries, blackcurrants, gooseberries, strawberries, etc.) are small fruits, rich in polyphenols and high in antioxidants. Although current research shows promising results, the US Food and Drug Administration (FDA) indicates that there is insufficient evidence to demonstrate the effectiveness of these compounds in the treatment and prevention of cancer. Nevertheless, amongst the functions attributed to berries are the ability to selectively block proteins that develop cancer, to interfere with the formation of new blood vessels near tumours and their progression, antioxidant capacity (scavenging off free radicals responsible for premature ageing) and the ability to develop mechanisms that induce apoptosis (death) of tumour cells. All evidence indicates that eating berries has a beneficial effect, but this research has so far only provided results at the laboratory level.
In order to verify that green tea consumption, due to its high antioxidant power, has the capacity to reduce the risk of developing cancer or to exert a curative effect, further studies on humans are still needed.
In recent years, much has been said and written about the health benefits of green tea, including that regular consumption can prevent cancer and help to cure it.
Drinking green tea is a good way to increase fluid intake and promote a good level of hydration, which is essential for a person undergoing cancer treatment. It will also provide antioxidants with beneficial health effects. High consumption of green tea (more than two cups a day) could lead to interactions with some of the drugs used in during treatment and you should consult your oncologist. Green tea contains theine, which has stimulant properties and is therefore not recommended to drink before going to bed or if you have insomnia.
Green tea contains a high proportion of polyphenols, such as epigallocatechin-3-gallate (EGCG), which is mainly responsible for its positive effects. Scientific laboratory and animal studies have shown it to be a strong antioxidant with the in vitro capacity to reduce the risk of developing certain types of cancer, inhibit tumour cells, induce tumour cell apoptosis, and reduce angiogenesis. However, these effects need to be tested in human clinical studies. Because different types are available on the market and different people prepare them differently, their function is conditioned by different factors and a lot more information is needed to establish definite recommendations.
The effects of flaxseed consumption on cancer treatment or prevention of cancer are not proven.
Some people undergoing treatment include flax seeds in their diet because they have heard or read about their possible benefits. There is a wealth of information online and from various sources which claim that eating flaxseed can prevent and cure cancer, mainly prostate, lung, colon, rectal or breast cancer.
Although the effects of flaxseed on cancer are not proven, a moderate consumption (one to three tablespoons per day) benefits the circulatory system. Integrating flaxseed into a balanced diet is safe and entirely optional but is not a medical recommendation. If consumed, they can be milled or blended to facilitate the absorption of fatty acids or left whole in case of constipation. If you want to take more, consult your oncologist, as excessive consumption may lead to drug interactions. In the case of hormone-dependent breast cancer, their use should also be reported because of their estrogenic capacity.
Scientific research suggests that flaxseeds may reduce the risk of cancer through the lignans (polyphenolic compounds with phytoestrogenic capacity), linolenic acid, or omega-3 fatty acids that they contain. Animal studies conclude that lignans act as antioxidants and that flaxseed reduces the formation, growth or spread of some types of cancer. Studies in humans are very limited and there is not enough scientific evidence at present to recommend flaxseeds as protective or as therapy during treatment.
There is currently insufficient scientific evidence to confirm that its consumption during treatment has beneficial effects on the disease, as clinical trials and dose-effect studies are lacking.
In recent years, curcumin in turmeric has been described as one of the components with the most possible beneficial effects in preventing and treating cancer. This has led to an increasing number of sources recommending its consumption during treatment.
Turmeric is completely safe to use as part of a balanced diet. Its traditional use in dishes, like that of other spices, would not have any harmful effects. In the case of high doses, the oncologist should be consulted, as it may interfere with certain drugs used in chemotherapy treatment.
Turmeric is a spice whose rhizomes contain curcumin, which is thought to have potential anti-cancer effects. Multiple laboratories and animal studies have shown that it has anti-tumour and apoptosis activity in a broad spectrum of cells. Studies have also shown it to have antioxidant properties (preventing angiogenesis, inhibiting cancer cells, and slowing the growth and spread of cancer) and anti-inflammatory effects on cancer cells. Human clinical trials on these effects of curcumin are in early stages, and it remains uncertain whether it will be introduced into cancer treatment.
As of today, there is no type of restrictive diet that has clear scientific evidence for its use in patients during cancer treatment. In fact, many of these diets can be potentially very dangerous during treatment.
Social media, mass media, and word of mouth are filled with messages and recommendations about 'miracle' alternative diets that claim to cure cancer, making it a widely practiced approach among individuals affected by cancer. Typically, these recommendations are made without the guidance of the oncology treatment team, potentially jeopardizing the patient's clinical and nutritional status. Similarly, the prescription or restriction of specific foods during cancer treatment should come from the treating medical team or the designated dietitian/nutritionist. Some of the most prevalent diets include the alkaline diet, blood type diet, macrobiotic diet, vegan diet, ketogenic diet, and intermittent fasting.
Adequate nutritional status is fundamental to cope with the disease and its treatments. The diagnosis of cancer does not necessitate a change in diet. In the case of unhealthy dietary habits, it is recommended to maintain a varied, balanced, and healthy diet that meets nutritional needs during this period. If you were following a vegan, macrobiotic, or vegetarian diet before the oncological diagnosis, you can continue doing so under dietary-nutritional supervision to ensure complete nutritional intake, but you should not make the change if it was not the case. Always consult with your designated medical team before following any diet that has not been prescribed within this team or hospital setting.
There is limited evidence regarding the benefits of alternative diets during cancer treatment. The use of ketogenic diets and intermittent fasting (in various modalities) has been more extensively studied. However, as of today, there is not enough scientific evidence to recommend any of them for cancer patients due to potential adverse effects. The use of other restrictive diets in many cases is based on theoretical reasoning, anecdotal cases, or unverifiable sources, lacking robust scientific evidence to support routine use. The existing evidence on vegan, vegetarian, macrobiotic, or plant-based diets is focused on cancer prevention, and very few studies have been conducted during the oncological process.
No. There are no scientific studies that have linked genetically modified foods to oncological processes.
There is a false belief that genetically modified or transgenic foods are linked to tumour processes. It is believed that by modifying the genes of the food, the genes of the people who eat it are also modified, giving place to mutations and the development of possible tumours.
The recommendation to follow a healthy and balanced diet based on the Mediterranean diet can be made whilst including genetically modified foods, as the European Union guarantees their safety. In addition, regulations make it compulsory to label all genetically modified foods and the ingredients containing or produced from genetically modified organisms (GMOs). Thus, whether to include them in your diet or not is a personal choice.
Genetically modified foods are those whose genetic material has been modified using modern genetic engineering techniques to give them a specific property, for example, to improve their nutritional characteristics, improve population nutritional deficiencies, enhance their growth, make them more efficient, or offer crop resistance to diseases or pests, amongst others. The EU guarantees that these foods are safe to eat before they are commercialized by checking that they do not cause allergies, do not transfer genetic material, are not resistant to antibiotics and that there are no significant nutritional changes. To date, there are no reliable scientific studies or proven evidence linking their consumption with the appearance of tumours or interference during cancer treatment.
Moderate coffee consumption during cancer treatment is safe, although its intake may or may not be recommended depending on the symptoms or side effects that arise. For this reason, it is always advisable to consult your medical team.
On the one hand, years ago, some scientific studies linked coffee intake to an increased risk of cancer, especially pancreatic cancer. Roasted coffee also generates acrylamide, a highly controversial chemical substance. On the other hand, more recent studies claim that coffee consumption may be associated with a lower incidence of developing some types of cancer and provide other beneficial health effects. These two facts have raised questions and doubts amongst people undergoing cancer treatment.
There is insufficient evidence to recommend the exclusion or ingestion of coffee during treatment, so its consumption is optional. The current recommendation is that moderate coffee consumption can be part of a balanced diet. The EFSA (European Food Safety Agency) advises not to exceed an intake of 400 mg of caffeine per day (a dose which, spread over the day, has no harmful effects). It is important to keep in mind that caffeine content depends on the type of coffee or dilution (amongst other things) and that on average, a cup of espresso contains about 80 mg of caffeine. Therefore, it is best not to drink more than four cups of coffee a day. A high caffeine intake can interfere with sleep patterns, cause digestive problems, or lead to imbalances in blood pressure.
Recent and better-designed studies than the initial ones have not found a connection between coffee and the onset of cancer. Even the World Health Organization (WHO) has removed coffee as a possible carcinogen, and its consumption is currently linked to multiple benefits for the immune system (by regulating inflammation) and a lower risk of developing certain types of cancer. This effect is attributed to its phenolic compounds with antioxidant properties and the ability to prevent oxidative damage to cellular components that contribute to the pathogenesis of inflammation, cancer, and neurodegenerative diseases. However, the evidence in this regard is inconclusive, and the results have a very low level of certainty, making it uncertain or doubtful to claim that coffee is beneficial to health.
There is currently no evidence linking an intake of food additives (within the acceptable daily intake) approved by the European Food Safety Authority with an increased risk of developing cancer or interactions during treatment.
There are still many reports today linking food additives to multiple adverse health effects such as allergies, intestinal dysbiosis, and increased risk of developing cancer or interactions with cancer treatments, leading to uncertainty about their safety and causing many people to avoid them.
The European Food Safety Authority (EFSA) reviews the safety of food additives regularly with a very thorough evaluation, the last of which was completed in 2020 with later revaluations in some specific cases such aspartame (see sweeteners myth). The letter E indicates that it has been approved and is safe for human consumption. Therefore, foods containing food additives can be part of a healthy and balanced diet. However, a healthy diet is one based on fresh, local and seasonal foods, with little or no processing, and above all without ultra-processed foods, so the intake of additives should be very low.
Food additives are substances intentionally added to food to perform technological functions: to give colour, to improve texture, to sweeten, to help preserve, amongst many others. There are many different types and additives should always appear in the list of ingredients on the packaging or container indicating the function they perform in that specific product. The scientific evidence on the negative effects of food additives is extensive, but often not very well documented or rigorous. This is why EFSA evaluates food additives exhaustively and establishes an acceptable daily intake for each additive (an estimate of the amount of substance that a person can ingest every day for a lifetime without it being a substantial risk to their health).