Sugar Feeds Cancer: Truth or Myth

The claim that sugar causes cancer is as common a claim as coffee is bad for your health, and just as false. But before we delve into explaining why this is an urban legend, let’s look at what sugar is.

There are several types of sugars and they’re classified according to their number of molecules. Table sugar, for example, is a disaccharide, meaning it’s made up of 2 sugars, glucose and fructose. Lactose, the sugar in milk, is also a disaccharide composed of glucose and galactose. Fructose and glucose are monomers. They count only one molecule. As chains of sugar accumulate like beads on a necklace, they stick together to form larger molecules and become polysaccharides. That’s the case in glycogen, the sugar stored in the liver or starchy foods such as rice and potatoes.

Sugar is an Essential Nutrient

Just like vitamins and minerals, sugar is an essential nutrient and is impossible to remove from the human diet. I find it amusing when influencers post recipes and recommendations about removing all sugar from their diet, or when some MLM hun showcases her sugar-free products for weight loss. Any sugar-free food or beverage will have artificial sweeteners, which are more damaging to your health than sugar.

Our entire body runs on glucose. That’s what circulates in our blood and gets carried to our cells for fuel. If you are familiar with hypoglycemia (an insulin dysfunction), then you know when the glucose level is low, a person becomes irritable, can’t concentrate, and feels weak. That is because the brain runs 100% on glucose, but it cannot manufacture it nor store it. It needs a constant supply.

You’ve certainly heard of diabetics shaking when their glucose level drops. If they don’t ingest something sweet immediately, they could faint. Everything we eat is converted to glucose and that includes protein.

If your diet doesn’t contain any sugar (a glucose source), your liver will convert fat or protein to glucose. But that process uses up micronutrients such as thiamine (vitamin B1), riboflavin (vitamin B2), niacin (vitamin B3), pyridoxine (vitamin B6), magnesium, and zinc. These are the cofactors that empower the mitochondria—the little furnaces that burn fat and protein to produce energy.

In summary, if your diet is high in fat and protein but contains almost no carbs, not only will you need a lot more micronutrients (more than present in your diet), but you will also produce free radicals as a result of excess mitochondrial activity. Without sufficient vitamin C, glutathione cannot be regenerated. This is an antioxidant made in the body and present in every cell to clean up any harmful compounds.

Now you can see how all these high-protein/low-carb diets cannot and should not be implemented long term.

Does Sugar Cause Cancer?

Back to our discussion of sugar and cancer. If glucose is the fuel of every cell in the body, it follows that cancer cells also need it for fuel and growth. Since they grow more rapidly than healthy cells, they need an even higher supply of glucose; if there isn’t enough around, they will steal it from healthy cells. Therefore, it’s futile to eliminate sugar from the diet.

Scientific research doesn’t show any evidence that sugar consumption leads to cancer, nor is it proven that it contributes to cancer cell proliferation. “Sugar is not a carcinogenic (cancer-causing) substance. However, over-consumption of sugar, particularly added sugars in processed beverages and foods, can contribute to obesity which is an important risk factor for cancer.

There is no evidence that consuming sugar makes cancer cells grow faster or cause cancer. There is a view that sugar “feeds” cancer cells. Most cancer cells grow faster than normal cells and therefore require more energy. It has been shown that glucose metabolism is often altered in cancer cells to meet the increased demand for glucose. However, this does not mean that consuming sugar will make cancer cells grow faster or cause cancer. All foods are broken down into glucose as all cells, not just cancer cells, require glucose for energy.” (1)

Which Sugars Are Healthy?

Just like there is healthy fats and bad fats, there are good and bad sugars. The best sugar is from carbohydrates (potatoes, pasta, whole grain bread, legumes). These are called complex carbs/sugars, meaning they take longer to digest and slowly stream into the blood without causing a spike and trough. In addition, these sugars come with much-needed healthful nutrients.

The second category is simple sugars (candy, fruit, honey, sucrose). They leave the stomach too fast, and even if you don’t eat a lot, the glucose is dumped all at once in the blood, causing a spike, which alerts the pancreas to release more insulin than necessary. All the glucose is carried to cells for storage. The low glucose triggers the desire to eat more.

This is why I recommend to my patients not to eat fruit by itself for breakfast. An hour later, they would feel ravenously hungry and may eat more than they need. That’s a recipe for weight gain. While some of these sugars are not harmful (fructose from fruit), they can be addictive and in excess will tip the scale.

The American Heart Association recommends 6 teaspoons of added sugars per day for women and 9 for men. The World Health Organization (WHO) advises no more than 10% (12 teaspoons) of daily calories should come from added sugars. (2)

Sugars to Avoid

The majority of sugar in the American diet comes from simple sugars, also known as refined sugar. Candy, snack food, sugary beverages, and desserts. These sugars have no nutritional value and target your waistline. Excess weight is associated with many physiological changes that lead to disease, including cancer. This is how sugar contributes indirectly to carcinogenesis.

Then there are added sugars. These can be artificial, real, such as sucrose or molasses, or refined sugars such as high fructose corn syrup and maltodextrin. These sugars sneak in where you least expect it: spaghetti sauce, salad dressing, canned vegetables, and cereal. The best way to avoid these added sugars is to read food labels and not purchase any foods that contain unnecessary sugars. You may have to spend a few more minutes in the grocery store, but as you continue doing it, you will spot brands and foods that have added sugar faster and buy their healthier versions.

The most dangerous sugars, though, are artificial sweeteners. To learn more about artificial sweeteners and their impact on health, you may read my previous post about this topic. These sugars have no nutritional value and are harmful to the microbiome (the friendly gut bacteria) and because they don’t provide the same satisfaction as sugar, you may end up eating a lot more. It’s been proven that artificial sweeteners do not help with weight loss; as a matter of fact, it’s the opposite. You may use this BMI calculator to determine if your weight falls into a healthy range.

Sugars to Include in Your Diet

Sugar that is healthy to consume is the one already included in fruit. You may also use honey, agave, maple syrup, and even table sugar. As long as it’s part of a balanced and healthful diet and your weight is within the health range, sugar is safe to eat.

Cancer Prevention Foods

You have heard the term eat the rainbow. It means your plate or bowl should always be colorful. Antioxidants that give plants their bright colors are the antioxidants we need to strengthen our defenses against cancer and diseases in general. Having a high-fiber diet also ensures a healthier digestion, lower cholesterol, and by removing excess estrogen, fiber also lowers the risk of breast cancer. So, go ahead, fight cancer with a fork!

Citations

1. Cancer Council Does sugar cause cancer? 

2. American Heart Association How Much Sugar Is Too Much?