Key takeaways
- Added sugars play a role in conditions that may increase the risk of cancer.
- 25 grams of added sugar daily is a healthy goal.
- Choose whole foods and prioritize complex carbs such as fruits, vegetables, nuts and seeds.
- Sweetened drinks, desserts and candy are the major sources of sugar in the American diet.
From Halloween candy to pumpkin pie to Christmas cookies and celebratory cocktails, sugar is everywhere during the end-of-year holidays. And that’s not the best news for our health.
While added sugars don’t directly cause cancer, they contribute to conditions that may increase the risk of disease, said Deborah Hong, MS, RDN. Hong is a dietitian with the Simms/Mann UCLA Center for Integrative Oncology, which provides free nutritional guidance and psychosocial support for people being treated for cancer at UCLA Health.
“Excessive amounts of processed foods that are high in fat, starches and sugars are indirectly linked to cancer risk or recurrence because they increase the risk of gaining unnecessary weight,” Hong said during a recent webinar, “Sweet Truths: How Sugar Affects Your Body and Cancer Risk.”
But it’s not just weight gain that could be the problem, she said. It’s also insulin resistance.
What is insulin resistance?
All types of carbohydrates – from fruits and vegetables to dairy foods, bread and pasta – naturally contain sugar. As we digest, we break these sugars down into glucose, the body’s preferred form of fuel.
When we eat, our blood-sugar levels rise, prompting the pancreas to produce insulin. This hormone acts as a key to unlock cells in our muscles and organs that allows them to receive the glucose they need for energy, which brings our blood-sugar levels back to normal.
When we eat too much sugar or carry a lot of excess weight, we don’t respond to insulin as well as we should. But the pancreas keeps producing it, hoping to unlock the cells and offload glucose. This leads to elevated levels of insulin, which can trigger the production of insulin-like growth factors, or IGF.
“IGF then promotes cell growth and division,” Hong said, “which can lead to an increased risk of certain cancers, such as breast cancer, prostate cancer, colorectal, lung, thyroid and childhood cancer.”
Even without insulin resistance, too much sugar can be a problem because it can feed cancer cells.
“Every cell in our body, including cancer cells, uses glucose as energy,” Hong said, and there’s no way to dictate where we want the glucose to go. “Because cancer cells grow and divide continuously – they don’t have the ‘stop’ mechanism – they require more energy compared to healthy cells.”
Limit added sugar
But the answer isn’t to cut all carbohydrates.
Instead, Hong recommends limiting added sugar and consuming more complex carbohydrates, such as whole fruits and vegetables, nuts and seeds.
Americans tend to consume about 17 teaspoons of added sugar a day, or 71 grams. A healthy target is around 25 grams a day, Hong said.
The major sources of added sugar in the American diet are sweetened drinks, desserts and candy. A sweetened iced tea, for example, could contain 29 grams of added sugar.
But sugar also hides in breakfast cereals and breakfast bars: “Choose one with 10 or 12 grams or less of added sugar (per serving),” Hong said. Sugar hides in dressings and sauces, such as ketchup, barbecue sauce, teriyaki sauce and hoisin sauce.
This is why it’s important to read nutrition labels, Hong said. In the “total carbohydrates” section of a nutrition label, there’s a line that shows how many grams of added sugar the product contains, along with what percentage of the recommended daily value that sugar represents. A percentage of 20 or higher is considered a high source of added sugar, she said.
Sugar substitutes, such as saccharin, aspartame or stevia, can help prevent insulin spikes, but don’t overindulge, Hong warned. Sometimes people think, “It’s not actually refined sugar, so I can eat more of it,” she said.
Choose whole, natural foods whenever possible and keep sweet treats to a minimum, Hong said.
“We want to promote more complex carbohydrates, because they contain natural sugars and also micronutrients and fiber necessary for our gut health, and they help manage our overall blood-sugar levels,” she said. “So be cautious of added sugars and sugar substitutes in foods, and try to cut down on both sources, if possible.”
