What are the body’s needs to deal with breast cancer? What foods should be preferred? Should we avoid some of them? All the answers on the diet to adopt during treatment and after illness with medical oncologist Dr Damien Vansteene.
Today, what do we know about the role of diet during the treatment of breast cancer?
Diet can be disrupted with cancer treatment, especially chemotherapy, which can cause nausea, canker sores, etc. So people change their diet. The main food that is diminished is meat, because it very frequently causes disgust. These are also all foods that generate strong odors. For us, the objective during treatments is to prevent patients from losing weight, so we give dietary advice: eat in small quantities but several times a day, consume foods that are a little richer by adding fats because they contain a lot of calories, find other sources of protein with fish, eggs, dairy products and legumes.
Are there certain fats to be preferred?
In theoretical laboratory studies, we have the impression that omega-3s have many virtues in oncology, but in clinical studies we fail to show these benefits. The problem is certainly the notion of dose that we cannot reach with food. But consuming enough omega-3s still has a real benefit. Afterwards, to enrich the diet, fresh cream can be a good alternative. It is also better to choose whole dairy products, add cheese to soups, purees and pasta, to have more fat.
Chemotherapy: avoid green tea which can have interactions with the treatment
During treatment, should I avoid certain foods or drinks?
There really aren’t any anti-cancer foods, and there aren’t any foods to avoid during illness either. What is important is to have a diversified diet, with enough fiber provided by fruits and vegetables. Then, the foods to avoid will rather be defined according to the side effects of the treatment. For example, someone who has canker sores will avoid eating nuts, chocolate or Emmental cheese.
On the other hand, there is a drink to limit during chemotherapy because it can have interactions with the treatment: it is green tea. The patient should therefore not consume it the same day or the following two days.
And what about alcohol?
For alcohol, everything depends on the quantity: the general recommendations in France are not to exceed more than ten glasses per week, two per day, with at least two days without any consumption. During the treatments, there is no risk of consuming alcohol if it is not in large quantities, nor every day. Afterwards, some patients are unable to do so on the evening of chemotherapy, for example, because the body does not support it… It is therefore to be seen according to the patients. And then after that is the question of why do we like alcohol? Is it a solitary consumption or with people because we have an event to celebrate? This nuance is important.
Concretely, on the day of chemotherapy, what is it advisable to eat?
On the day of chemotherapy, a person can eat quite normally. Some patients nevertheless prefer to eat lighter, but this is specific to each person. On the other hand, patients are often advised to plan a meal to heat up in the evening to avoid getting tired with cooking.
Could a vegetarian or vegan diet be harmful to the patient during treatment?
During cancer, nutrient needs increase, especially protein needs. So for vegetarians who manage to consume eggs regularly, there are no problems. It can be more complicated for vegans to meet these protein needs on a plant-only diet. But it also depends on the people, whether they are sufficiently educated in nutrition regarding vegetable alternatives to animal proteins in order to avoid any deficiency.
Post-cancer diet: “It all depends on the habits the person had before”
After the treatments, can the person go back to their old eating habits or must they follow a special diet?
We don’t have a lot of data on what to eat after cancer. By default, it is advisable to follow the primary prevention recommendations to avoid the disease. It all depends on the habits that the person had before: if his diet was unbalanced, cancer is an opportunity to review his dietary balance a little. Concretely, you must eat five portions of fruit and vegetables a day by diversifying them, consume whole grains which provide interesting fibers for transit and the intestinal microbiota, take two dairy products, and limit products that are too fatty, too salty or too sweet. We can favor foods with a nutri-score A or B, obviously knowing that we can only eat nutri-scores A and B because vegetable oils, for example, do not obtain scores higher than C for best. In fact, it is rather necessary to choose the product which has the best score compared to others in the same food category. It is also recommended to limit the consumption of red meat to 500 grams per week.
What if you have any advice for patients reading this article?
What I say to people with cancer who have questions about diet is to turn to health professionals (dietician, nutritionist, oncologist, etc.), and pay attention to what is circulating on Internet. We see a lot of advice with people who say that you have to eliminate such a food or eat another… But sometimes, it can be harmful to eliminate certain foods or to consume others in too large quantities. And be careful with food supplements too!