Does Sugar Feed Cancer?

18 Sep 2014 by Krystal Barter
Does Sugar Feed Cancer?

 Carolyn McAnlis, Dietitian and Pink Hope Ambassador discusses sugar and cancer.


Sugar is getting a lot of attention in the media lately, but it’s certainly not a new ingredient. So why has it become a hot topic? There are a few reasons why many foods have become sugar-laden products, and this is assumed to be one of the major reasons that obesity rates continue to rise.

In the 1990’s, fat became the enemy of dieters. In an effort to cater to these diet trends, and increase revenue, manufacturers created low-fat products – but they needed to make these products taste good without fat. So they turned to sugar. A great example of this is yoghurt. Full-fat yoghurts are very creamy and palatable; by taking away the fat, it can be bitter and lacking in taste. Sugar was added to create a “diet” food that was low in fat, but this resulted in a product that is high in sugar.

When salt also became an ingredient to avoid due to the risk of high blood pressure, food companies needed a preservative to use in processed foods. So they turned to sugar, which is a natural preservative just like salt. Chemically, both salt and sugar draw water out of cells, which reduces the chance of bacterial contamination. This way, companies could market products as “low fat” or “low sodium,” which appealed to the public, but provided added sugars.

While we have always known that food companies use these strategies, it has gotten worse as processed foods have become readily available and we are buying more convenience items. Today, you’d expect to see sugar in bread, cereal, peanut butter, salad dressings, and even ketchup.

Why is sugar bad?
Eating sugar (and foods that breakdown into sugar like glucose) cause the pancreas to release insulin into the bloodstream. Insulin is a hormone that helps cells absorb the sugar to use for energy. This process is necessary for us to get energy from our food. It’s like a lock and key – cells are locked and can’t absorb glucose unless there is insulin present in the blood to unlock it.

The more sugar we eat, and over time, the pancreas is put under stress trying to keep up with our sugar consumption. When the pancreas cannot make enough insulin to keep up, this is called insulin resistance and is a pre-cursor to type 2 diabetes. Even for a healthy person, blood sugar spikes and lows can cause symptoms like irregular heartbeat, fatigue, trouble concentration, sweating, and even loss of consciousness. Spikes in blood sugar, over time, can damage the vessels of the heart, kidneys, eyes, and nerves.


What about cancer?
Does sugar feed cancer? In short, yes – but it’s more complicated than that. Sugar feeds all cells in the body, which includes cancer cells if they are present. We need some amount of sugar to keep our organs functioning, especially the brain. Because carbohydrates are essential for brain function, the body has several strategies in place to create carbohydrates from protein or fat even if we don’t consume any sugar. This means that, even if we try to avoid all carbohydrates (which is extremely difficult), our body will still find a way to manufacture them. Which means that cancer cells will still have a way to get energy. We are still learning about how the metabolism of cancer cells work, but currently, it seems that trying to deprive cancer cells of sugar through diet will not slow their growth.

While avoiding all carbohydrates is very hard, it is very easy to consume too much, which can lead to weight gain and insulin resistance, which in turns increases risk for many types of cancer. Recent studies have shown a link between high consumption of sugar and certain gastrointestinal cancers like oesophageal cancer. There is also evidence that low consumption of sugar can improve survival rates of some cancers, including breast cancer. Researchers are looking into a link between insulin resistance and cancer risk, as well as the potential benefit of very low carbohydrate diets for cancer survival. These diets are very hard to stick to, however, and may not be a good idea for those undergoing treatment.

Avoiding added sugars is the best recommendation for overall health, and increasingly for preventing certain cancers. Before you run out to buy “sugar-free” products, keep in mind that food companies are very good at advertising. They want to create a good-tasting product in order to earn your money. So they will find a way – generally this is achieved by using alternative sweeteners, some more natural than others.

Because of this, the best way to avoid added sugars or artificial sweeteners is to make things from scratch as much as possible and eat whole foods. An easy swap is the fruited yogurt. Simply buy plain yogurt, which usually does not have added sugar (always check the ingredient list!), and add your own fruit.




We are still learning about the metabolism of cancer cells, but unfortunately it does not seem that a very low carbohydrate diet will “starve” or kill cancer cells.

However, reducing sugar consumption has numerous benefits, including cancer prevention, as well as reducing the risk of obesity and the many problems that are associated with it.

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