Cancer and Diet : a practical guide based on experience
At the beginning of my treatment (which lasted 15 months), the doctors all told me the same thing : "Treat yourself when it comes to food. I think that's a bit short-sighted. It seems more complex than that.
The impact of nutrition on cancer treatment
On the one hand, I think food plays an important role in managing the side effects of chemotherapy. On the other hand, I'm sure that a poorly nourished organism (with food that gives you pleasure, but whose nutritional value is questionable) will not stand up well to the onslaught of various treatments. It will become weaker and degraded. Finally, there are various approaches to starving cancer cells; most oncologists are skeptical about them. However, they are worth considering. For example, the ketogenic diet (i.e., carbohydrate intake reduced to a minimum) offers interesting possibilities, since cancer cells feed on sugar. The role of the microbiota in cancer development and control is still a mystery.
Specifically, here's what I did :
My nutritional tips during and after cancer
Eliminate/ diminish gluten
Gluten is a potential inflammatory agent (I know, it's controversial), and it takes a lot of energy to digest (you know that heavy feeling after eating pizza? That's your digestive system attacking gluten, mixed with cheese). And you don't have a lot of energy during chemotherapy. You might as well spend it on something other than digestion.
Prioritize fruits and vegetables
Eat lots of fruits and vegetables (whenever possible). The first phase of chemotherapy is terribly constipating (as result of cyclophosphamide and anthracycline and heavy pre-medication to avoid allergic reactions and limit nausea). So you need a lot of fiber. In any case, a regular supply of minerals and vitamins is essential.
Avoid fried food
Fried food is difficult to digest and requires a lot of energy. In addition, it systematically gave me diarrhea during phase 2 of chemotherapy.
Ketogenic diet and its possible impact on chemotherapy
I had a strict ketogenic diet for three days around phase 1 chemotherapy sessions (two days before, one day after) : the ketogenic diet consists of cutting out all sources of carbohydrates (slow and fast) in favor of a high intake of noble fats (not French fries) and proteins (green vegetables, eggs, meat, almonds, hazelnuts, etc.). The idea is to protect healthy cells from the effects of chemotherapy, since they "go to sleep" in the absence of sugar and learn to function with the help of lipids. Cancer cells would not have this ability and would be weakened by a ketogenic diet. In addition, the ketogenic diet would limit the side effects of chemotherapy.
In practice, I don't know if this theory works. My observation is that I had little nausea and was able to eat throughout the treatment, which was not a given.
Protein intake and anemia
Make sure you eat protein regularly : I lost five kilos (10% of my body weight) during chemotherapy. Weight loss inevitably leads to loss of muscle mass, which is exacerbated by inadequate protein intake. Chemotherapy also causes anemia (very high in my case). Iron intake is important, and red meat is one of the most effective and assimilable sources. In fact, I had a terrible craving for steak during chemotherapy (which completely disappeared afterwards). I'm almost a vegetarian now).
Strongly limit fast sugars
They have an inflammatory effect on the body and are addictive, with yo-yo energy effects (the famous glycemic spike followed by a big crash). What's more, as I've already mentioned, there is a strong suspicion that cancer cells may run on sugar, so it makes sense to limit consumption. I continued to eat chocolate, choosing those with a high cocoa content. Since it was summer, I also ate berries.
Reduce consumption of dairy products
I had identified dairy products from cows as a source of various digestive problems for some time. I continued my efforts to eat as little as possible. What's more, some research suggests that high consumption of industrially produced dairy products may promote the development of cancer cells. Milk from intensively farmed cows has a different (more harmful) composition than milk from "happy" cows. Forget this cruel and unnatural industry. Consider buying cheese from alpine pastures or local producers. Eat dairy products made from goat's or sheep's milk, which are easier to digest.
Limit coffee
Coffee is also inflammatory and acidifies the body. It wasn't difficult for me. After a few weeks, the smell of coffee made me nauseous (as it did during my pregnancies, strangely enough).
Limit alcohol
This should be easy. Alcohol and chemotherapy don't mix well. The wines you used to love will taste awful, and you'll probably pay dearly for a few glasses of alcohol. And it's not recommended by the medical community: your body is already full of toxic substances during chemotherapy. There's no need to add more. In addition, the treatment causes a chemical menopause, with all that goes with it, including the famous hot flashes that alcohol makes worse. Last but not least, regular alcohol consumption is considered a risk factor for breast cancer (according to WHO).
Adapt your dietary preferences
Chemotherapy can significantly change your sense of taste and smell (like pregnancy). Foods you used to love may seem unpleasant. Try different cuisines. For me, Asian (non-spicy) cuisine in all its variations has been my lifeline. I was delighted to rediscover Vietnamese cuisine, which has many qualities: it's not necessarily very spicy, it's often soft (essential with a ravaged mouth), it tastes different, it's healthy.
Limit spices
Chemotherapy often affects the mouth: mouth ulcers, altered taste, hypersensitivity. Spice will not be your friend. I remember crying after a slightly spicy Thai soup.
Omegas are your friends
Take omega 3 and 6 in order to nourish the skin and mucous membranes, which are dried out by chemotherapy. The discussion around phyto-estrogens found in some plants containing Omega 6 is a bit confusing (borage appears to be safe). Talk with your oncologist if your cancer is hormone-sensitive. Omega-3 are found in fish oils. I took and still take OmegaBiane DHA + EPA capsules.
Adapt your diet to the circumstances
There was a period at the end of the 2nd phase of chemotherapy when I ate what I could, i.e. what didn't attack my mouth and didn't cause diarrhea. I didn't care about its nutritional value. Do the best you can. That's a lot.
Towards a conscious and well balanced diet
Indulge, yes, but with respect for your body, which is going through a period of considerable turbulence. And for those of you who tend to gain weight during treatment (which often happens), a conscious attitude should allow you to limit the damage.
Cancer has made me critically re-evaluate the way I eat (when I honestly thought I already had healthy eating habits). The connection between food and cancer seems obvious to me. It's not possible to continue the same eating habits during and after cancer, even for someone who has never had weight problems.
Special features of HER2-positive breast cancer
Research on HER2-positive breast cancer (which involves a genetic mutation in certain breast cells that leads to over-expression of the HER2 gene. These mutated cells multiply rapidly and uncontrollably) has not identified a specific cause. However, researchers point to a combination of environmental, lifestyle (including diet) and genetic factors (this does not mean that cancer is hereditary). One of the things I can directly control is the way I eat.
The influence of cancer on my current diet
I now eat a more varied diet, with fewer carbohydrates and more whole foods. I've become a flexitarian (I eat fish sometimes, chicken rarely, and red meat almost never). I feel much better, both physically and mentally. And it's one of the fastest ways to make a positive impact on your carbon footprint).
I know that this change has been relatively easy for me because I have a less emotional relationship with food and I have the financial means to make it happen. I realize that's not the case for everyone. I can only encourage you to look at your relationship with food and start a small revolution. Observe how your body reacts to certain foods and follow your instincts to determine what is (really) good for you. You'll go through periods where the simple act of eating is a struggle. You'll have to experiment, make mistakes, try something different, day after day, without sticking to your old habits.
PS1: This is not medical advice; it's just a sharing of experiences. Check with your doctors if what you want to do or try is compatible with your treatment.
PS2: I am not sponsored by any of the brands mentioned in this document. I'm just telling you what worked for me and what I found in Switzerland. That's it.
PS3: If you suffer or have suffered from eating disorders, get help to change your eating habits.