The Harold Leever Regional Cancer Center

The Sugar Dilemma

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“I’ve been told to avoid all sugar and white flour since it can make my cancer grow. Is this true? Do I have to give up everything that I love?” The question about sugar and cancer is undoubtedly the most frequently asked nutrition question at the Leever Cancer Center, and it often creates fear in patients who are already anxious. The answer is complex and brings up many issues about the role that our food plays in preventing and/or promoting health and disease.

 Will sugar make my cancer grow faster?

It is important to understand that sugar feeds every cell in our body, including cancer cells. In fact, out bodies need glucose (the simple sugar found in our blood) for energy or fuel. Even if you cut out every bit of sugar in your diet, your body would make sugar from other sources, such as protein and fat.

So cancer cells need sugar to grow, just like healthy cells need sugar to grow. Eating sugar will not make the cancer cells grow any faster; unfortunately, they do that all on their own. However, consuming large quantities of sugar can create other imbalances that may possible affect the growth of cancer cells. 

Should I be concerned about sugar?

Even though sugar doesn't exactly "feed" cancer cells by making them grow faster, it is a good idea to limit the amount of sugar that you eat. Most very sweet foods are loaded with "empty calories." But even more importantly, too much sugar may make our bodies produce excess insulin, a naturally occurring substance that helps transport glucose to our cells. It is beneficial for our bodies in small amounts, but in large quantities, it can speed up cell growth. This can be a good thing if the cells are normal and healthy, but a bad thing if they are cancerous. In other words, sugar does not "feed" cancer cells, but too much sugar may result in excessive insulin production, which may, in turn, encourage cancer cells to grow.

Should I avoid all sugar?

You don’t have to avoid every bit of sugar in your diet. But there are choices that you can make that are better than others regarding good sugars and bad sugars.

Good sugars, also called complex carbohydrates, are usually unprocessed and found in fruits, vegetables, beans, legumes and whole grains, providing a generous helping of vitamins, minerals, protein and fiber. Because they are unprocessed, they are absorbed more slowly. The slower the absorption, the less insulin one produces. To get the slowest rise in insulin, add fiber, protein and fat to your carbohydrate-containing meal or snack. For example, if you drink a glass of fruit juice, your glucose — and therefore insulin — will rise rapidly. If you have fresh fruit instead of the juice, there are more fiber and complex carbohydrates, so the glucose and insulin rise more slowly. If you have fresh fruit with a handful of nuts, you are taking in complex carbohydrates and fiber (from the fruit) AND protein and fat (from the nuts) so the glucose and insulin will rise even MORE slowly.

Bad sugars, also called simple sugars, are found in foods that offer little, if any, nutritional benefit, and are often high in calories. Some examples include soda, sweets (cakes, candy, and cookies), sugary cereals, juice drinks and refined grains like white rice and white pasta. Simple sugars enter the bloodstream quickly and cause a rapid rise in insulin.

The key to reducing insulin is to reduce your intake of simple sugars, and increase your intake of complex and more nutritious carbohydrates. Many studies have shown that a diet high in fruits, vegetables, whole grains and legumes, appears to fight cancer, as well as other diseases like heart disease, diabetes and high blood pressure.

Added sugar can be disguised in many forms. Some experts estimate that the average American consumes 350-475 calories worth of sugar a day (18-24 teaspoons) which can add up to a lot of extra weight, and contribute significantly to the obesity epidemic in our country. “How can that be?” you might ask. “I don’t put extra sugar on my food!” Sugar comes disguised with an Assortment of names on food labels (see box on left). Next time you pick up packaged or processed food, read the labels carefully. The American Heart Association recommends no more than 6 teaspoons per day for women and 9 teaspoons for men.

Bottom line: Cutting back on the sugar in your diet
  •  Choose complex carbohydrates while possible (fresh fruits, vegetables, beans, legumes, whole grains)
  •  Avoid or limit processed foods and simple carbohydrates (crackers, cookies, sweetened breakfast cereals, and condiments like sweet and sour sauce)
  •  Cut back on soft drinks and sweetened beverages
  •  Read ingredient labels and look for added sugars
  •  Switch from regular jelly to all-fruit spreads
  •  "Sweeten" foods with fresh fruits
  •  Save sweets and treats for special occasions; homemade is better than store-bought
If you are a cancer patient and are actively getting treated:

Sometimes when it is difficult to swallow or your sense of taste has changed, you have to consume foods that are often sweeter than usual (smoothies, commercially prepared high-calorie or high-protein beverages). This is usually a temporary situation, and getting in calories and protein to prevent weight loss is a high priority. You are NOT worsening your disease by consuming these foods during treatment. If you make a smoothie, add some complex carbohydrates, a good protein source and some fat and/or fiber, so your body will benefit!

Once your treatment is completed, or if your treatment does not affect your ability to eat, you may benefit from reducing your intake of simple sugars, replacing them with complex carbohydrates. If being overweight is an issue, cutting some empty sugar calories can pave the way for a healthier body and lifestyle! Will it slow down the growth of the cancer cells? The answer is complex, but you may be reducing the overall level of insulin in your system, and therefore reducing inflammation and potential for disease.