How Do High Fructose Diets Harm The Immune System?

Fructose is a natural sugar that can be found in fruits, some vegetables, and honey. This type of natural fructose sugars can be good for your health as fruits and vegetables contain less sugar than processed, sugar-sweetened foods.^(1,2) However, on the other hand, high fructose corn syrup (HFCS) is a manufactured sweetener that is made from cornstarch.^(3,4,5) Due to its low cost, many manufacturers of soft drinks and processed foods, especially in the United States, have started using high fructose corn syrup to sweeten their products.^(6,7)

Health experts remain divided on whether high fructose corn syrup causes more harm than other sugars. While the Food and Drug Administration (FDA) state that they have found no evidence that foods containing high fructose corn syrup are in any way less safe than foods that use other sweeteners, but many experts believe that added sugar and high fructose corn syrup are the biggest factors in the obesity epidemic of today.^(8,9,10) High fructose corn syrup and other forms of added sugar are also linked to many other serious health conditions, including heart disease and diabetes.^(11,12)

At the same time, the 2020-2025 Dietary Guidelines for American has also not singled out high fructose corn syrup, but it does recommend that people should restrict their consumption of all forms of added sugars.⁽¹³⁾

One of the biggest issues with high fructose corn syrup is that it is present in a wide variety of processed foods, including some foods that people might not expect, including salad dressing and frozen pizza.

A 2019 study by the University of California found that culturing human dendritic cells in fructose caused an increase in inflammation.⁽¹⁴⁾ Human dendritic cells play a major role in the immune system. However, the research team did not go ahead and further investigate the metabolic mechanism behind why this happens.

Now, a new study published in the journal Nature Communications by researchers from the Swansea University’s Medical School, the Francis Crick Institute in London, and the University of Bristol has examined how mouse and human cells react to being exposed to fructose.⁽¹⁵⁾

The researchers found that a diet rich in fructose can disrupt the functioning of the immune system. The research team discovered that fructose causes inflammation in the immune system, and this, in turn, increases the production of reactive molecules, which are also associated with inflammation.

Fructose, especially, makes adjustments to the cellular metabolic pathways to boost the production of reactive inflammatory cytokines.⁽¹⁶⁾ The authors noted that fructose reprograms the cellular metabolic pathways in the body to start favoring oxidative metabolism and glutaminolysis, which are processes that are required to support the increased inflammatory cytokine production. This type of inflammation can have a profound impact on the body as it causes damage to the cells and tissues and also contributes to organs and entire bodily systems to stop functioning properly, thus causing various diseases.

This study is an essential step in furthering the understanding of why certain diets can cause diseases and some promote good health.

The new research has also provided new data on how fructose could be linked to obesity since inflammation is typically associated with obesity. Furthermore, the study also discovered that fructose leaves the cells of the body more susceptible to further metabolic challenges. This suggests that people whose diets are high in fructose are at a greater risk of poor outcomes when fighting against infections or facing other metabolically challenging environments.

The researchers have also stressed that it is essential to understand what effect regular intake of fructose has on cellular functions, as humans all over the world have increased their consumption of high fructose corn syrup.

The fructose present in high fructose corn syrup can lead to many health issues if eaten in excessive amounts or regularly had. Most starchy carbohydrates, like rice, get broken down into glucose, which is the primary form of carbohydrates. However, high fructose corn syrup and table sugar are made up of nearly 50% glucose and 50% fructose.⁽¹⁷⁾

Glucose gets easily transported and used by each and every cell in the body, and it is also the predominant energy or fuel source when we are doing high-intensity exercises and other processes. On the other hand, the fructose present in high fructose corn syrup or table sugar has to be converted into glucose, fat, or glycogen (stored carbohydrates) by the liver before it can be used as fuel by the body.

Similar to regular table sugar, high fructose corn syrup is a rich source of fructose. Simultaneously, the last few decades have witnessed a sharp increase in the intake of fructose and high fructose corn syrup. Whereas earlier, before high fructose corn syrup and table sugar became affordable and commonly available, people’s diets only had a limited amount of fructose in them and that too from natural sources like fruits and vegetables.⁽¹⁸⁾

Your body metabolizes fructose in a different way than glucose. Consuming too much fructose can lead to various health problems, some of which are discussed below.

Regular and high intake of fructose can leads to increased liver fat. A study carried out in both men and women who were overweight found that drinking sucrose-sweetened soda for six months dramatically increased the amount of liver fat, as compared to drinking diet soda, milk, or water.⁽¹⁹⁾

Another study found that fructose can increase the amount of liver fat to a much greater extent when compared to the same amount of glucose.⁽²⁰⁾

Liver fat accumulation can cause many serious health problems in the long term, including type 2 diabetes and fatty liver disease.^(21,22)

Several long-term studies have shown that an excessive intake of sugar, including high fructose corn syrup, plays a major role in the development of obesity.^(23,24)

Excessive intake of fructose also boosts visceral fat accumulation. Visceral fat surrounds your organs and is known to be the most dangerous and harmful type of body fat. It is commonly referred to as belly fat. Belly fat is linked to health issues like heart disease and heart disease.⁽²⁵⁾

Excessive consumption of fructose or high fructose corn syrup can cause insulin resistance, a condition that can lead to type 2 diabetes. The regular consumption of excess fructose can also make your body become resistant to the effects of insulin.⁽²⁶⁾ This can lower the body’s ability to control blood pressure and insulin levels.

Apart from diabetes, high fructose corn syrup can also play a role in metabolic syndrome, which is known to cause many diseases like heart disease and some types of cancers.⁽²⁷⁾

There are many types of serious diseases that have been linked to the excessive consumption of fructose. High fructose corn syrup and sugar have been found to promote inflammation in the body, which is linked with a higher risk of diabetes, heart disease, obesity, and cancer. Apart from inflammation, the excess intake of fructose can also increase dangerous substances in the body known as advanced glycation end products (AGEs), which may cause a lot of harm to your cells.^(28,29,30)

It may also aggravate inflammatory diseases like gout because of the increased production of uric acid and inflammation.^(31,32)

Considering so many health issues and diseases linked to the increased intake of high fructose corn syrup and sugar, it is hardly surprising that studies have started showing the link to an increased risk of heart disease and even reduced life expectancy.⁽³³⁾

Similar to other added sugars, high fructose corn syrup is simply composed of empty calories. Even though it contains plenty of calories, but it has no essential nutrients that can benefit you in any way.

This is why consuming high fructose corn syrup will reduce the total nutrient content of your diet, and the more high fructose corn syrup you consume, the lesser room there will be for nutrient-dense foods.

The research team is hopeful that findings from their study will inspire further research that could help experts develop a treatment for a wide range of conditions, including infectious disease and cancer. Research into various components of our diet can be helpful in understanding what contributes to disease and inflammation and what can be changed to improve our health and overall well-being.

There is no doubt that in the last few decades, high fructose corn syrup has become widely available and very affordable. Experts now attribute many serious health conditions to the excessive intake of high fructose corn syrup, including heart disease, diabetes, insulin resistance, metabolic syndrome, obesity, and many others. Avoiding the intake of high fructose corn syrup along with added sugar in your diet can go a long way in improving your health and lowering the risk of disease.

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