Living with cancer


Adequate food control during cancer treatment is essential to maintain the body's nutritional balance, since the side effects of some medications can interfere with the acceptance and digestion of food. Learn more.
7 min read
per: Grupo Oncoclínicas
Nutritional control in cancer treatment is essential, as the side effects of can interfere with the acceptance and digestion of food.

Over the decades, studies carried out in all parts of the planet indicate that food plays an important role in the development, spread and also in the prevention of cancer. Among cancer deaths caused by environmental factors, diet contributes approximately 35%. An adjusted, balanced and adequate diet could prevent three to four million new cases of cancer a year.

As important as the adoption of a diet with the aim of preventing cancer or the return of the disease is the concern with nutrition during cancer treatment. The side effects of treatments such as chemotherapy interfere with the acceptance of a series of foods², and the answer to maintaining the nutritional balance of the patient’s organism lies in the diet itself: with what is placed on the plate and in the glass, it is possible to alleviate such problems. adverse effects and ensure that you take whatever is necessary to keep the body strong to go through the fight against cancer.

The loss of appetite and the change in taste, which is natural during the treatment period, should also be taken into account. Malnutrition is common among these cancer patients, ranging from 40% to 80% of cases. That’s because the constant side effects take away their desire to face a plate of food.

Learn what to include and what to take out of your diet – and practical tips for doing so –, learn about the main myths and truths about nutrition during cancer treatment, and learn which medical experts to count on to make everything simpler.

What to include in your diet during cancer treatment

Certain foods or ways of preparing and consuming them are most effective against each type of cancer treatment side effect.

To relieve nausea and vomiting:

• Eat cold or frozen foods;
• Eat acidic and citrus foods (lemon, orange, strawberry and pineapple, for example); and
• Eat small portions several times a day.

To prevent or relieve diarrhea discomfort:

• Increase your intake of healthy fluids such as water, tea and juice.

Against constipation:

• Eat fiber-rich foods such as beans, peas, lentils, chickpeas, soybeans, brown rice, flaxseeds and oats; and
• Drink lots of water.

Against mucositis (mouth sores):

• Give preference to soft and/or pasty foods (legume creams – peas, lentils, corn-, purees, soft breads, ice cream, puddings, jellies; and
• Eat cold or frozen foods.

To improve dry mouth sensation:

• Drink lots of fluids (water, tea, juice, soup);
• Eat acidic and citrus foods (lemon, orange, strawberry and pineapple, for example);
• Suck on ice cubes; and
• Before meals, apply industrialized artificial saliva ointments in the mouth.

In addition, it is important to take into account that, in order to face the need to repair the adverse effects of surgery, chemotherapy and radiotherapy treatments, the immune system needs to be strengthened.

To strengthen the immune system, the ideal is to include foods rich in antioxidants in the daily diet, such as garlic, almonds, sweet potatoes, broccoli, spinach, low-fat yogurt, watermelon and cabbage.

Hydration is another important point in nutrition during cancer treatment, as many toxic compounds from chemotherapy and radiotherapy are eliminated through urine⁶. Adequate consumption of water is therefore necessary to aid in the detoxification of the body. The ideal is to drink mineral or filtered water.

In general, cancer patients should maintain a diet that favors foods of plant origin: fruits, vegetables, whole grains and legumes (beans and peas, for example). These ingredients have the power to inhibit the arrival of carcinogenic components to cells and also to repair damaged DNA when the aggression has already started. If the cell is already altered to a point beyond repair, some nutritional compounds are able to promote its death, preventing the continuation of the disordered multiplication of diseased cells.

When consuming meats, whether red or white, preference should be given to those prepared steamed, stewed, stewed or roasted.

Studies relating the Mediterranean diet to the prevention and/or treatment of cancer have shown the beneficial effects of eating the foods that form the basis of this diet – fish, fruits, vegetables, virgin olive oil and wine – in containing the progression of the disease.

What to take out of your diet during cancer treatment

Certain foods or ways of preparing and consuming them worsen the side effects of cancer treatment.

To relieve nausea and vomiting:

• Avoid or reduce the use of strong seasonings in food preparation; and
• Don’t overfill your plate at each meal.

To prevent or relieve diarrhea discomfort:

• Do not consume concentrated sweets, cream, butter, cheeses and whole-grain breads, which are laxatives;
• Avoid natural foods that loosen the gut, such as cow’s milk and fruits like papaya, oranges, grapes and black plums.

Against constipation:

• Avoid adding refined cereals to meals, such as white rice, refined wheat flour, cornmeal, corn starch and preferably whole grains.

Against mucositis (mouth sores):

• Avoid spicy, salty and/or heavily seasoned foods; and
• Do not consume acidic and citrus foods (such as lemon, orange, strawberry, pineapple).

To improve dry mouth sensation:

• Avoid foods rich in salt; and
• Do not over-season the food;

During treatment, foods with higher amounts of fat, sugars and sodium, such as processed meats, sausages (sausages, sausages and salami, for example, as they contain high amounts of sodium and fat), soft drinks, alcoholic beverages and artificial juices, should be avoided.

Very well done or fried meats, such as barbecue, can contain carcinogenic chemical compounds formed during preparation, and should be consumed in moderation.

8 practical nutrition tips to make everyday life easier during treatment

1) For physical and psychological reasons, foods with a “taste of home” are better accepted by cancer patients. Cooking at home or having someone who can do it for the patient or even relying on specialized home delivery services are good ways to face the plate with more desire to eat.

2) Filling 2/3 of the plate with vegetables, fruits, whole grains, legumes, nuts and seeds is a good way to ensure the necessary nutritional support.

3) Limit the daily consumption of salt to the equivalent of 1 coffee spoon – thus, the taste of food is maintained, but health is not harmed.

4) Check food labels for the amount of sodium, compare it to similar products and choose the one with less of this component.

5) Use natural seasonings in food preparation; instead of using that ready-made supermarket seasoning, how about chopping garlic, onion and green herbs at home?

6) Avoid drinking fluids during meals. They make food pass faster through the gastrointestinal tract and, consequently, decrease the body’s ability to absorb nutrients.

7) Creating a food routine – with times and duration of each meal – is a good strategy to ensure constant nutritional support. The body adjusts its biological clock to these times and intervals quickly.

8) Eat seven to eight meals a day. Fractionating food increases appetite.

Which doctors should advise on nutrition during cancer treatment

With regard to food and nutrition, the multidisciplinary treatment against cancer must include, in addition to the oncologist, nutrologists and nutritionists.

Myths and truths about nutrition during cancer treatment

Every cancer patient needs artificial food supplementation

MYTH. Most people do not need supplementation, as a balanced diet tends to be enough to protect the body. The use of pills, capsules, powders and liquids to supplement vitamins and minerals should only be done after physical and clinical examinations, if the doctors monitoring the treatment consider it necessary. Taking supplements on your own can harm your health and compromise treatment.

Pork should be avoided during cancer treatment

MYTH. Many believe that pork interferes with the healing and regeneration of the body during cancer treatment, but there is no scientific basis to confirm this relationship. In any case, it is better to consume its “lean” versions, that is, with less fat, such as roast loin.

Can you cure cancer with just food?

MYTH. Although a healthy and balanced diet is essential and helps in the treatment against the disease, no food has the power to cure any type of cancer.

Eating iron-rich foods such as liver, red meat and kale helps fight anemia in chemotherapy patients.

MYTH: In many cases, anemia that occurs in chemotherapy patients is not related to iron deficiency, but to other factors. For the treatment of iron deficiency anemia, iron supplementation through medication is recommended.

Consumption of nuts can prevent the appearance of polyps in the intestine

TRUTH. Studies indicate that consuming a serving of nuts, such as Brazil nuts, walnuts and almonds, three times a week reduces the occurrence of polyps in the large intestine.


1 Journal of Nutrition – Diet and cancer: an epidemiological approach. Available at:

2 Abrale – Food and cancer. Available at:

3 Hospital Alemão Oswaldo Cruz / Oncology Center – Patients undergoing cancer treatment must adjust their diet. Available at:

4 Hospital Nove de Julho – Cancer and food: a more important relationship than you might think. Available at:

5 Asbran – How to fight malnutrition in cancer patients. Available at:

6 Living Space – Food and Cancer. Available at:

7 INCA – Food. Available at:

8 INCA – Foods of plant origin. Available at:

9 INCA – Meat preparation method. Available at:

10 ACS Journals – Adherence to the Mediterranean diet and grade group progression in localized prostate cancer: An active surveillance cohort. Available at:

11 Hospital Alemão Oswaldo Cruz / Oncology Center – Food for Cancer Prevention. Available at:

12 WeCancer – The 7 nutrition precautions for cancer patients. Available at:

13 INCA – Food supplements. Available at:

14 Beat Cancer Institute – Nutrition. Available at:

15 INCA – Myths and Truth: Food. Available at:

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