What we eat has long been known to impact our health, and a wealth of research suggests that our eating patterns impact our risk for diet-related chronic diseases. More recently, the conversation surrounding how some dietary choices may lead to the development of chronic inflammation in the body has become a hot area in preventative nutrition. In our Food and Inflammation series, we take a closer look at how different dietary factors are related to inflammation. Our first article focused on gluten. In this next article, let’s look at the connection between sugars and inflammation.
What Is Inflammation?
Inflammation is a natural process in the body that refers to the immune system’s response to an irritant. In fact, inflammation is how the body protects and heals itself. If you’ve ever had a paper cut or burned your tongue while drinking a hot cup of coffee, your body’s process of healing that wound was the inflammatory response in action. Cuts and burns cause acute inflammation, which is a relatively short-lived physiological healing response. Acute inflammation may also be brought on by infectious factors like bacteria and viruses, non-infectious factors like injuries and chemicals, and psychological factors like stress and excitement.
In contrast, chronic inflammation is a long-term physiological response that can last anywhere from weeks to years. Unlike acute inflammation, chronic inflammation is not always visible to the naked eye. It can be brought on by a number of factors, including autoimmune conditions, chronic stress, long-term exposure to pollutants, physical inactivity, and the foods and beverages we regularly eat and drink. A state of constant inflammatory response can create chains of destructive bodily reactions that damage cells and are linked to increased risk for adverse health conditions like diabetes, cardiovascular disease, dementia, depression, and certain cancers.
The Connection Between Food and Inflammation
Inflammation is a complicated process, and the connection between food and inflammation is still being researched. Many individual foods and nutrients are thought to help promote or reduce inflammation. Although consuming certain specific nutrients like vitamin E, magnesium, fiber, and antioxidants like polyphenols can reduce inflammation, our overall diets also have a collective effect on inflammation. For example, dietary patterns that include high consumption of refined starches, added sugars, and saturated and artificial trans fats; and are low in fruits, vegetables, whole-grains, and omega-3 fatty acids, have been associated with increased inflammation.
One food component that is often accused of increasing inflammation in our bodies is sugar.
Sources of Sugar
Sugars occur naturally in a wide variety of fruits, vegetables, and dairy foods. Sugars are also produced commercially and added to foods and beverages. When you hear the word “sugar” in the context of its negative effects on health, more than likely the word is referring to added sugars.
There is no formal recommendation for how much naturally occurring sugar to consume, but there is a recommendation for added sugars. The current Dietary Guidelines for Americans recommend limiting our intake of added sugars to less than 10% of our total calories consumed per day, with more specific recommendations provided depending on how many calories a given person needs each day. For reference, one 12-ounce can of regular soda contains about 150 calories from added sugars, which equates to 7.5% of the calories in a 2,000-calorie diet. The average American consumes about 13% of their daily calories from added sugars, with sugar-sweetened beverages (also known in the food and nutrition field as SSBs) such as sodas, energy drinks, sweetened fruit-flavored beverages, and sport drinks being the largest source, accounting for about one-quarter of the calories we consume from added sugars. One-hundred-percent fruit juice is not considered an SSB because it does not contain added sugars—it only contains sugars that are found naturally in the stated fruit.
Is Sugar Inflammatory?
Most of the research conducted on the health impact of consuming added sugars has focused on SSBs. While research has shown that SSB consumption is associated with weight gain and health conditions such as gout, hypertension, and type 2 diabetes, studies looking at the impact of natural and added sugars consumed in forms other than SSBs have not come to the same conclusions.
In addition to specific health conditions, researchers have also investigated the association between sugars and inflammation. Most of this research has been done in animal models or observational studies of humans. Observational data has found an association between added sugar consumption—particularly when consumed from SSBs—and low-grade chronic inflammation. For example, a 2014 observational study showed increased risk for having high blood levels of an inflammatory marker called C-reactive protein among people who self-reported consuming 20% or more of their daily calories from SSBs.
Results from published human clinical trials are inconclusive about the causal role of added sugars in inflammation. However, excess consumption of calories, including those from added sugars, can contribute to weight gain and obesity, and low levels of chronic inflammation often result from having obesity.
Individual types of sugars have also been studied in order to understand their potential roles in inflammation, in part because there are differences between how some sugars are metabolized by the human body. When we consume sucrose, for example, it gets broken down into equal parts of the monosaccharides fructose and glucose. Glucose is readily absorbed and made available for use by any cell in the body with the help of insulin, whereas fructose is handled in the liver through a process that does not require insulin. Excess fructose consumption promotes the synthesis of fatty acids in the liver, which may create byproducts that can help kick-start inflammatory processes. However, it is not known whether or not this fatty-acid synthesis in the liver is due to fructose or if it is a consequence of also consuming excess calories. Overall, research examining the type of sugar that contributes most to inflammatory processes has been mixed, with some studies showing no difference.
Should We Go Sugar-Free?
If you consume more added sugar than is recommended, reducing how much you consume is a good idea. A wealth of research confirms that our added sugar intake should be limited, but sugar itself need not be feared, nor does it need to be eliminated completely from our diets in order for our eating patterns be considered healthy and even anti-inflammatory. When considering the impact of sugar on inflammation and your overall health, the important part to remember is not whether you consume sugar at all, but rather the amount of added sugar you consume, and what else you eat and drink along with it.
This article includes contributions by Debbie Fetter, PhD.