A robust immune system helps support a long and healthy life. Your lifestyle has a lot to do with how well your immune system works, and a new study has found that a sugar commonly found in processed foods may be sabotaging immune system function.

Fructose is a naturally-occurring sugar found primarily in fruit and to some degree in vegetables. Consumption of fructose has increased significantly in recent years, but unfortunately, the increase isn’t due to a greater intake of fruit and vegetables. It is instead the result of how common it is to add high fructose corn syrup along with sucrose, or table sugar, which is made from equal parts of glucose and fructose, to processed foods.

The best defense against consuming too much fructose is learning to pay attention to the ingredient list on food labels.

Fructose causes inflammation in the immune system, which leads to the production of molecules that provoke more inflammation and ultimately leave us prone to diseases, researchers at the University of Bristol and Swansea University concluded after a laboratory study on the effects of fructose on the immune system at the molecular level. They found fructose reprograms cellular metabolic pathways in a way that results in increased production of cytokines, small proteins crucial in controlling the growth and activity of blood cells and other cells that normally help the body's immune and inflammation responses, leading to ongoing inflammation.

Chronic inflammation is associated with diseases such as type 2 diabetes, high blood pressure, heart disease, mental illnesses, autoimmune diseases, gastrointestinal disorders and some types of cancer.

Fructose is lurking in many of the foods we routinely purchase and eat every day. The best defense against consuming too much fructose is learning to read the ingredient list on food labels.

Ingredients that should tip you off to the presence of a fructose-based sugar include high fructose corn syrup, corn syrup, maize syrup, glucose syrup or any ingredient containing some form of the term, “fructose.” If you see any of these words near the beginning of a product’s ingredient list, you might want to put that item back and look for a substitute.

Fructose sweeteners are found in a wide range of foods. Packaged prepared foods such as breakfast cereals, granola, granola/nutrition/protein bars, frozen pizza, crackers, packaged fruits, peanut and other nut butters, breads, pasta, fruit juice drinks, soft drinks, candy, prepared desserts, salad dressings and other condiments, not to mention fast foods, all can add to immune system inflammation.

Most of us rely too much on the convenience of processed, packaged foods and fast food. We could all improve our diets and our health by cooking our own food at home and from scratch as often as possible, not only to avoid fructose sweeteners but to control other aspects of our diet such as fat and sodium.

We’d likely lose weight, too. Changing some food practices and eating habits to boost our immune system is a small price to pay for the potential to avoid developing chronic diseases.

The study is published in Nature Communications.