AUTHORITY NUTRITION

Does Sugar Cause Inflammation in the Body?

Written by Mary Jane Brown, PhD, RD on November 12, 2017

Inflammation is part of the body’s natural healing process.

During injury or infection, the body releases chemicals to help protect it and fight off any harmful organisms. This can cause redness, warmth and swelling.

Some foods, like sugar, can also cause inflammation in the body, which is normal.

However, eating too many inflammatory foods may cause chronic low-grade inflammation. This can cause serious health problems, such as heart disease, diabetes, cancer, and allergies (1, 2, 3, 4).

This article covers all you need to know about the role of sugar and inflammation in the body.

Too Much Added Sugar Is Linked to Inflammation

Woman Eating Cheesecake

Several animal studies have shown that a diet high in added sugar leads to obesity, insulin resistance, increased gut permeability and low-grade inflammation (5).

Human studies confirm the link between added sugar and higher inflammatory markers.

A study of 29 healthy people found that consuming only 40 grams of added sugar from just one 375-ml can of soda per day led to an increase in inflammatory markers, insulin resistance and LDL cholesterol. These people tended to gain more weight, too (6).

Another study in overweight and obese people found that consuming one can of regular soda daily for six months led to increased levels of uric acid, a trigger for inflammation and insulin resistance. Subjects who drank diet soda, milk or water had no increase in uric acid levels (7).

Drinking sugary drinks can spike inflammation levels. Moreover, this effect can last for a considerable amount of time.

Consuming a 50-gram dose of fructose causes a spike in inflammatory markers like C-reactive protein (CRP) just 30 minutes later. Furthermore, CRP remains high for over two hours (8).

In addition to added sugar, eating too many refined carbohydrates has also been linked to increased inflammation in humans (9, 10, 11).

In one study, eating just 50 grams of refined carbs in the form of white bread resulted in higher blood sugar levels and an increase in the inflammatory marker Nf-kB (10).

Summary Consuming too much added sugar and refined carbohydrates is linked with elevated inflammation in the body as well as insulin resistance and weight gain.

How Added Sugar Affects Your Body

Consuming excess added sugar and refined carbohydrates causes several changes in the body, which help explain why a diet high in sugar can lead to chronic, low-grade inflammation.

  • Excess production of AGEs: Advanced glycation end products (AGEs) are harmful compounds that form when protein or fat combine with sugar in the bloodstream. Too many AGEs leads to oxidative stress and inflammation (12).
  • Increased gut permeability: Bacteria, toxins and undigested food particles can more easily move out of the gut and into the bloodstream, potentially leading to inflammation (5, 13).
  • Higher “bad” LDL cholesterol: Excess LDL cholesterol has been associated with higher levels of C-reactive protein (CRP), a marker of inflammation (6, 14).
  • Weight gain: A diet rich in added sugar and refined carbohydrates can lead to weight gain. Excess body fat has been linked to inflammation, partly due to insulin resistance (15).

It is important to remember that inflammation is unlikely to be caused by sugar alone. Other factors like stress, medication, smoking and excess fat intake can also lead to inflammation (15).

Summary Excess consumption of added sugar and refined carbohydrates is linked to increased AGE production, gut permeability, LDL cholesterol, inflammatory markers and weight gain. All of these factors can trigger low-grade chronic inflammation.

Added Sugar Can Lead to Long-Term Health Problems

Observational studies in humans have linked high added sugar and refined carbohydrate intake to many chronic diseases, including heart disease, cancer, diabetes, obesity and more.

Heart Disease

Several studies have found a strong link between consuming sugary drinks and an increased risk of heart disease (16).

A large study involving more than 75,000 women found that those who consumed a diet high in refined carbohydrates and sugar had up to a 98% greater risk of heart disease, compared to women with the lowest intake of refined carbs (17).

This is likely due to the impact of sugar consumption on heart disease risk factors, such as increased LDL cholesterol, increased blood pressure, obesity, insulin resistance and increased inflammatory markers (16, 18).

Cancer

Several studies show people with high sugar intakes may be at a greater risk of developing cancer (19, 20, 21, 22).

One study found that when mice were fed high-sugar diets, they developed breast cancer, which then spread to other parts of the body (3).

One study looking at the diets of over 35,000 women found that those who consumed the most sugary foods and drinks had double the risk of developing colon cancer, compared to those who consumed a diet with the least added sugar (20).

While more research is needed, it is thought that the increased risk of cancer may be due to the inflammatory effect of sugar. In the long-term, inflammation caused by sugar may damage DNA and body cells (23).

Some experts believe that chronically high insulin levels, which can result from consuming too much sugar, may also play a role in cancer development (24).

Diabetes

Studies link the increased consumption of added sugar to type 2 diabetes (25, 26, 27, 28).

A large analysis including over 38,000 people found that just one serving of sugary drinks daily was associated with an 18% greater risk of developing type 2 diabetes (26).

Another study found that increasing corn syrup intake was strongly associated with diabetes. In contrast, fiber intake helped protect against the development of diabetes (27).

Obesity

Obesity is often referred to as a low-grade inflammatory disease. Eating too much added sugar is linked to weight gain and obesity (29, 30).

Experts suggest that modern diets, which are often high in refined carbs and added sugar, can lead to an imbalance in gut bacteria. This may partly explain the development of obesity (9).

A review of 88 observational studies found that a higher intake of sugary soda was associated with greater calorie intake, higher body weight and lower intake of other important nutrients (31).

One study in mice found that a diet high in sugar counteracted the anti-inflammatory effects of fish oil and promoted obesity (4).

Other Diseases

A high intake of added sugar and refined carbs has been linked to the development of other diseases, such as liver disease, inflammatory bowel disease, mental decline, arthritis and others (2, 32, 33, 34).

In particular, excess fructose consumption has been linked to non-alcoholic fatty liver disease. How this happens isn’t fully understood, but is thought to be due to a mix of increased gut permeability, bacterial overgrowth in the gut and ongoing low-grade inflammation (35).

However, evidence connecting sugar to health problems is mostly based on observational studies. Therefore, they cannot prove that sugar alone was the cause of these health problems (34).

Summary Observational studies have linked excess added sugar consumption to the development of several chronic diseases, such as diabetes, heart disease, obesity and cancer.

Natural Sugar Is Not Linked to Inflammation

It’s important to note that there is a difference between added sugar and natural sugar.

Added sugar is removed from its original source and added to foods and drinks to serve as a sweetener or increase shelf life.

Added sugar is found mostly in processed foods and drinks, though table sugar is also considered an added sugar. Other common forms include high-fructose corn syrup (HFCS), sucrose, fructose, glucose and corn sugar.

Among US adults, around 13% of total calories come from added sugar. This is high, considering that government guidelines advise that no more than 5% to 15% of calories should come from both solid fats and added sugar (36).

Excess amounts of added sugar and refined carbs have been linked to inflammation (6, 9, 10).

However, natural sugar has not been linked to inflammation. In fact, many foods containing natural sugars, such as fruits and vegetables, may be anti-inflammatory (37).

Natural sugars include those naturally occurring in foods. Examples include fructose in fruit and lactose in milk and dairy products.

Consuming natural sugars should not be any cause for concern. That’s because they act very differently than added sugar when consumed and digested in the body.

Natural sugar is usually consumed within whole foods. Thus, it is accompanied by other nutrients, such as protein and fiber, which cause natural sugars to be absorbed slowly. The steady absorption of natural sugar prevents blood sugar spikes.

A diet high in whole foods like fruit, vegetables and whole grains can have other health benefits, too. There is no need to limit or avoid whole foods (38, 39, 40).

SummaryAdded sugar, which is removed from its original source and added to foods and drinks, is associated with inflammation. Natural sugar, which is found in whole foods, is not.

Lifestyle Changes Can Reduce Inflammation

The good news is that certain lifestyle changes, such as reducing your intake of sugary and processed foods, can lead to lower inflammation levels in the body (41).

For example, consuming fructose has a dose-dependent impact on inflammation. This means the more you eat, the greater the inflammation in the body (42).

In addition, a sedentary lifestyle, smoking and high stress levels have also been associated with chronic low-grade inflammation (43, 44, 45).

However, regular physical activity has been shown to reduce belly fat and inflammatory markers in humans (46).

Therefore, it seems possible to reduce inflammation levels by making dietary changes.

One study found that replacing processed foods with whole, unprocessed foods improved insulin resistance, improved cholesterol levels and reduced blood pressure, all of which are related to inflammation (47).

Another study found that reducing fructose consumption improved inflammatory blood markers by almost 30% (41).

Below are some simple tips to help reduce inflammation:

  • Limit processed foods and drinks: By reducing or eliminating these products, you’ll naturally exclude key sources of added sugar like soda, cakes, cookies and candy, as well as white bread, pasta and rice.
  • Read food labels: If you are unsure about certain products, get into the habit of reading food labels. Look out for ingredients like sucrose, glucose, high-fructose corn syrup, maltose and dextrose.
  • Choose whole-grain carbs: These include oats, whole-grain pasta, brown rice, quinoa and barley. They have lots of fiber and antioxidants, which can help control blood sugar and protect against inflammation.
  • Eat more fruits and vegetables: Fruits and vegetables contain antioxidants, vitamins and minerals, which can protect against and reduce inflammation in the body.
  • Eat lots of antioxidant-rich foods: Fill your plate with foods rich in antioxidants, which naturally help counteract inflammation. These include nuts, seeds, avocados, oily fish and olive oil.
  • Keep active: Regular physical activity, including both aerobic and resistance exercise, can help protect against weight gain and inflammation.
  • Manage stress levels: Learning to manage stress levels through relaxation techniques and even exercise can help reduce inflammation.
Summary Replacing foods and drinks high in added sugar and refined carbohydrates may help lower inflammatory markers. Including whole foods in your diet can also help fight inflammation.

The Bottom Line

The evidence suggests that eating too much added sugar and too many refined carbohydrates causes inflammation in your body.

Over time, the inflammation caused by poor dietary habits may lead to several health problems, such as heart disease, diabetes, liver disease and cancer.

However, inflammation can also be caused by many other factors, including stress, medication, smoking and excess fat intake (15).

There are several things you can do to help fight inflammation, including exercising regularly and effectively managing your stress levels.

Furthermore, cut down on processed foods and drinks, choose whole foods, and limit your intake of added sugar and refined carbohydrates.

An evidence-based nutrition article from our experts at Authority Nutrition.

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