Sugar is a treat, but it may play tricks with your health

There is no evidence that sugar causes cancer or helps cancer grow, but it may contribute to an unhealthy lifestyle that may increase cancer risk.

Forget witches, ghosts and goblins. One of the scariest things about Halloween is the candy you and the kids will be eating. Too much sugar can be a bad thing, but that doesn’t stop us from craving it.

The United States is a nation with a sweet tooth. Estimates vary, but they agree that the average American eats a lot of sugar every day. Some estimates put the amount at about 17 teaspoons of sugar daily, while an analysis from the U.S. Department of Agriculture puts the average as high as 34 teaspoons a day. These estimated levels are up to six times higher than those recommended by the American Heart Association, which suggests no more than six teaspoons (25 grams of sugar) a day for women and nine teaspoons (38 grams of sugar) a day for men. 

While there is no evidence that sugar causes cancer or helps cancer grow, it may contribute to an unhealthy lifestyle that may increase cancer risk. For instance:

  • Too much sugar may contribute to weight gain and obesity, one of the most significant lifestyle risk factors for developing cancer.
  • Research suggests that diets high in added sugars tend to be low in important nutrients, including calcium, vitamin A, zinc and fiber. A healthy diet is considered key to helping reduce cancer risk.

Does sugar feed cancer?

There is no conclusive research that proves sugar causes cancerous cells to grow. While it is true that cancer cells need sugar to grow, the same could be said for nearly every cell in the body. If you were to avoid all sources of natural sugars found in grains, vegetables, fruits, milk and beans, you would starve healthy cells, which could result in malnutrition.

There is some evidence that consuming large amounts of sugar that produce a high glycemic index—rapidly increasing blood sugar levels—may be associated with an increased risk of certain cancers, including esophageal cancer. And a 2010 study found that fructose may fuel the growth of pancreatic cancer. Studies of a high glycemic index diet and cancer risk are mixed, but suggest a high glycemic index diet may increase risk of some cancers, especially in those who are overweight, inactive, which may increase risk of insulin resistance.

Experts recommend you avoid consuming large amounts of refined sugars—the bad sugars found in soda, candy, cakes, etc.—and get your sugar intake from whole foods. Besides being an excellent source of naturally occurring sugar, fruit contains many vitamins, minerals, phytochemicals and fiber that may help with achieving and maintain a healthy body weight, maintain cellular integrity and help support the immune system.

Naturally occurring sugars found in nutrient-dense foods like whole fruit aren't driving America’s high-sugar diets. Instead, the problem comes from "added sugars," those added to foods during a company’s manufacturing process or during a consumer’s preparation routine. Most of the added sugars Americans eat or drink come from soft drinks and other sugar-sweetened beverages, from grain-based desserts like cookies and cakes, from candy and sweetened dairy products, like ice cream, and from the table sugar used in coffee and tea.

The World Health Organization’s (WHO) dietary guidelines and the 2020 Dietary Guidelines for Americans recommend that added sugars make up no more than 10 percent of a person’s daily calories. The WHO also recommends for “additional health benefits,” no more than 5 percent. For a 1,500-calorie diet, the 10 percent cap means no more than 150 calories, or 38 grams of sugar. The 5 percent level would be half that amount.

Why is sugar bad for you?

Foods high in added sugars tend to be heavily processed and low in nutrients, and they may also be high in unhealthy fats. These foods offer little nutritional value to your body and may fill you up and take the place of nutrient-dense foods in your diet.

Excess sugar may lead to unhealthy weight gain, forming fat around the midsection, and high blood-sugar levels, which may cause insulin resistance. Research shows that limiting your intake of added sugars reduces your risk of becoming overweight or obese or developing tooth decay. Excessive sugar consumption has been linked to a higher risk of chronic diseases and conditions—in part by increasing the risk for metabolic syndrome—including:

Heart disease: The risk of heart disease increases among those who get more than 25 percent of their daily caloric intake from added sugars.

Type 2 diabetes: The risk of diabetes may be reduced by limiting the added sugar intake to 5 percent of total daily calories, which improves glucose tolerance and decreases the prevalence of diabetes and related metabolic abnormalities.

Non-alcoholic fatty liver disease (NAFLD): Large amounts of added sugars such as fructose may create a buildup of fat in the liver, which may increase the risk of this disease. Carrying extra weight and being inactive also may increase risk. Reducing sugar intake may be of benefit for NAFLD.

High blood pressure and metabolic dysfunction: Added sugars may increase blood pressure, heart rate, inflammation, insulin resistance and “broader metabolic dysfunction,” according to a review in the journal Open Heart.

Do artificial sweeteners cause cancer?

You may have heard that artificial sweeteners are the culprit for the increased incidence of cancer in the United States. However, according to the National Cancer Institute, the scientific evidence is unclear whether these sugar-free sweeteners cause cancer. It is recommended that people limit the amount of artificial sweeteners they consume by practicing moderation.

Sugar and sweetener do’s and don’ts

Added sugar comes under many names—such as maltose, dextrose, glucose and lactose—all of which should be avoided to maintain a healthy diet. Examples of added sugars include:

  • High fructose corn syrup
  • Brown sugar
  • Agave syrup
  • Sucrose/table sugar
  • Honey
  • Molasses
  • Raw sugar

In terms of healthier sugar consumption, seek to include only naturally occurring types of sugar in your diet. Many dietitians recommend eating six to nine half-cup servings of fruits and vegetables each day. You can sneak in some added sugar items, but it’s better to do so only once in a great while and not every day.

Remember that your body is getting sugar from other sources, too. The body breaks down carbohydrates—found in breads, pastas and rice—into simple sugars. These carbs turn into glucose. Other items that don't seem sweet, such as ketchup or barbecue sauce, also may have lots of sugar.

When you want to sweeten a drink or food, a good sugar substitute is stevia. Stevia is derived from the sweetleaf plant, which is naturally sweet and appears safe to use in moderation. It is a healthy, zero-calorie alternative to added sugars that is 300 times as sweet as sugar.

If you're trying to kick the sugar habit altogether, you may try drinking mint tea or chew gum with xylitol in it; both will help curtail sugar cravings.

If you have questions about the health benefits or side effects of sugar substitutes, consult your physician.

But I thought agave was natural?

Health-conscious people searching for a natural sweetener have probably come across agave nectar. In recent years, agave has been touted as a natural sugar substitute that can be added to beverages, baked goods and other foods in need of a boost of sweetness.

However, contrary to popular belief, agave is not a natural sweetener. It is highly processed, refined from the root of the agave plant. In fact, some experts argue that agave is worse for your health than other sugar, such as high-fructose corn syrup (HFCS). Both agave and HFCS contain fructose, which is the sugar naturally found in fruit. HFCS contains about 55 percent fructose, whereas agave contains closer to 90 percent.

What’s wrong with fructose?

In excess, fructose may be harmful to overall health. Sweeteners are made from extracted and concentrated forms of fructose, making it easier to consume an excessive amount of sugar. Fructose has been shown to enter the bloodstream more slowly than glucose, and stay longer. Potential health problems may include mineral depletion, insulin resistance, high blood pressure and cardiovascular disease. It also may contribute to the growth of pancreatic cancer.

This doesn't mean you should limit or avoid fructose from whole fruit. In a healthy diet, moderation is the key. Fruit has fiber that should fill you up before the fructose in it approaches excessive levels.

Get healthy recipes that are low in sugar.