Does sugar feed cancer?

Author: Sandra Krstev Barać, Master of Nutrition

Let's get this straight: the belief that consuming sugar promotes the spread of malignant cells is one of the most common misconceptions among the oncology population and an unnecessary source of anxiety among patients and their families. Although sugar and malignant diseases have a complex relationship, there is no evidence that completely eliminating these sweet molecules from the diet will stop the progression of the disease.

What we call sugar today is actually sucrose, a simple molecule composed of glucose and fructose that is broken down into glucose in the body and thus provides a quick source of energy for cells. All of our cells use glucose for their needs, so our body has several mechanisms to keep blood glucose levels stable. Even without the intake of carbohydrates, whether complex or simple, the body will provide glucose from other sources such as fat and protein.

The same is true for cancer cells. It is true that malignant cells are large consumers of glucose. However, unfortunately, they are also extremely adaptable and in the absence of glucose, they find other sources of energy, such as glutamine, acetate and lactate. Cancer, therefore, "feeds" on numerous nutrients, so the thesis that it can be "starved" by manipulating the diet does not hold water.

The only case when it may be appropriate to limit carbohydrate intake to the maximum and turn to a ketogenic diet is with glioblastoma, but even then this diet is not useful for all patients. Learn more about the ketogenic diet as a support for standard oncology therapy at the link.

The dangers of restrictive dietary patterns

First of all, it is important to be aware that glucose is extremely difficult to eliminate from the diet. Namely, all foods that contain carbohydrates are broken down into simple sugars, including glucose, during digestion. In other words, cereals, legumes, fruits and vegetables, milk and dairy products that make up an important part of the desired diet of oncology patients ultimately serve as a source of glucose.

Despite common sense, some oncology patients tend to eliminate all carbohydrates from their diet, unaware that they are doing more harm than good. Such a restrictive diet, among other things, often leads to unintentional weight loss, loss of muscle mass and malnutrition, the consequences of which can make treatment difficult and be fatal for patients. Additionally, foods rich in sugars are a quick source of the necessary energy and make food more palatable and attractive, which helps in cases of loss of appetite caused by therapy.

Sugar is still wise to limit

Now that it is clear that completely eliminating sugar will not destroy cancer cells, we must still be aware that foods rich in simple sugars such as cakes, cookies, chocolate and other sweets are not the happiest option in our daily diet. Namely, table sugar does not provide any valuable nutrients, except for the hated sucrose, so it is often referred to as “empty calories”. Empty calories are not necessarily bad, but the fact is that few people can afford them.

There is another reason why sugar should only be an occasional treat. Although it does not promote the spread, there is evidence that, indirectly, it can increase the risk of developing a malignant disease. Excessive sugar consumption can lead to weight gain, which, in turn, increases the risk of cancer. In addition, frequent sugar consumption increases levels of insulin and insulin-like growth factor I (IGF-1), which further increases the risk of the disease.

The point of the sugar story

Instead of obsessing over what fuels malignant cells, the focus in the diet of cancer patients should be on what “feeds” and gives strength to healthy cells, which are proteins, vitamins, minerals and other essential nutrients, which are provided, among other things, by foods rich in complex carbohydrates.

The message to take away is that, although, nutritionally speaking, sugar is not the most desirable food in the diet, cancer patients can enjoy sweet tastes in moderation and do not have to feel anxious or guilty if they decide to occasionally treat themselves to a treat as part of a varied and balanced diet, just like the healthy population.

Continue reading: Can beta glucan boost immunity and help fight cancer?

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