Food Intolerances and Genetics

As the American diet has evolved, people have started to eat more unhealthy, processed foods that are typically loaded with flour, sugar, and processed, refined carbohydrates. This diet is harmful for a number of reasons, but it can be especially harmful to people who are intolerant to some of these diet staples. As scientists continue to learn more about how these intolerances impact people’s risk for other diseases such as insulin resistance and diabetes, it is crucial that we all take steps to identify any food intolerances that we may have so that we can avoid some of these long-term consequences. Let’s explore some of the details of flour, sugar, and processed refined carbohydrates intolerances.

Gluten & Flour Intolerance

Flour intolerances can be caused by several different mechanisms. Gluten sensitivity is one common reason why people may want to avoid wheat flour along with other grains that contain gluten protein. One form of this condition can cause uncomfortable systems, such as stomach bloating and other GI issues. Scientists have discovered a number of common genetic variations that are linked to gluten sensitivity that can be detected with genetic testing.

Another reason someone may not tolerate flour well is celiac disease. This condition is a different form of gluten sensitivity because your body has a true immune response when you ingest gluten. This can cause symptoms such as inflammation, gastrointestinal distress, malnutrition, and an autoimmune response. Some people with celiac disease may experience worse symptoms than others, and these symptoms can worsen as you age. Celiac disease is a genetic condition, meaning it often runs in families. The genes associated with celiac disease can be detected by genetic testing. It is extremely important for people with celiac disease to consult with their doctor in order to get a correct diagnosis as quickly as possible. If this disease is not diagnosed, it can lead to more serious issues such as autoimmune disease, osteoporosis, anemia, and liver disease.

Treatment for any kind of gluten intolerance requires that a person eliminates gluten-containing products from their diet. In most cases, people also may need to remove any foods that could be cross-contaminated with gluten. Gluten is present in wheat, barley, and rye. Typical breads, pastas, cereals, and many sauces must be excluded from your diet in order to properly remove this substance. Most processed foods that come in a bag, jar, bottle, or box potentially have gluten in them, which makes it very important to check nutrition levels for any amounts of gluten or gluten-containing products like wheat.

Sugar & Sweetener Intolerance

Similar to flour intolerance, there are multiple forms of sugar intolerance. For people with sugar intolerances, cravings and weight gain are common symptoms. Sugar intolerances can also result in significant blood sugar spikes, even in people who do not have diabetes or prediabetes.

One type is fructose malabsorption , which is fairly common in the population, with about one in three people affected. Fructose malabsorption more often affects people who typically consume multiple sugary beverages, such as sodas, every day.

Another type of sugar intolerance is lactose intolerance. People with lactose intolerance lack an enzyme called lactase which breaks down lactose, the sugar found in dairy products such as milk and ice cream. This can make it hard to digest food items containing lactose, which can lead to the same gastrointestinal issues seen with other food intolerances. The most common cause of lactose intolerance is called primary lactose deficiency. Scientists have linked this disorder with a genetic variation that can be inherited from your parents. Genes associated with lactose intolerance can be detected by commonly available genetic tests.

Sugar intolerance can cause excessive food cravings and significant weight gain. For people with a genetic risk of excessive hunger, lack of satiety, or addictive eating behaviors, this sugar intolerance can be especially serious. Research has indicated that sugar addiction affects some of the same genes and pathways as cocaine and heroin addictions.

The main complication for people with sugar intolerance is obesity. In the United States, 42.5% of people over 20 years old are obese, and 73.6% of the population over 20 years old is either obese or overweight. People have differing degrees of genetic risk for diabetes, food addiction, excessive hunger, and lack of satiety. While some people can tolerate some sugar in their diet, for others it can be extremely harmful, leading to obesity and related complications, such as diabetes.

Treatment for sugar intolerance focuses on removing sugar from the diet. If you have symptoms of sugar intolerance or are genetically at risk, consider following an elimination diet protocol to determine what foods you may be sensitive to.

What is Considered Sugar?

Sugars, including sweeteners, take many forms and have been shown to have an inflammatory effect on the body. This includes any type of processed sugar/sweeteners or foods and drinks with added sugar/sweeteners, such as many desserts and sodas.

There is also evidence that shows excess sugar/sweeteners intake can cause the synthesis of free fatty acids in the liver, which would cause further inflammation. Additionally, high sugar/sweetener intake is known to be associated with increased obesity rates, which is also linked to higher inflammation. Knowing this, a decrease in dietary sugar/sweeteners is extremely beneficial due to the reduced risk of inflammation, obesity, and the numerous diseases that come along with them.

Artificial Sweeteners Foods with Sugar Additives
Acesulfame K Table Salt
Advantame Dairy Products
Alitame Yeast
Aspartame Chocolate
Aspartame-Acesulfame Salt Dextrose
Cyclamate Dextrin
Neohesperidin DC Maltodextrin
Neotame Fructose
Saccharin Dyno
Sucralose Cerelose
Aclame Puretose
AminoSweet Sweetose
Candarel Glucose
Cologran Sorbitol
Equal Sucrose
Heremesetas Xylitol
NatraTaste Inositol
NutraSweet Sodium Erythorbate
Sweet'N Low
Sweet One

What is Considered Processed, Refined Carbohydrates?

Processed, refined carbohydrates take many forms: grains, corn, soy, and wheat. These foods are used heavily in things that come in packaging like a box, can, jar, or bag. Refined carbohydrates tend to be high in calories and have a high glycemic load, which can make them fattening. Typical animals are raised eating corn, soy, and other grains to fatten up for market. In fact, about half of the corn grown in the US goes to fattening livestock.

One of the most common forms of processed, refined carbohydrates is high fructose corn syrup. This substance is included in most fast foods, sodas, and packaged goods. This raises the glycemic load and adds addictive, unhealthy calories to these foods.

Read food labels for some of the most common corn by-product names, including:

Corn Flour Maltodextrins
Cornmeal Dextrose
Corn Gluten Fructose
Cornflakes Crystalline Fructose
Popcorn Hydrol
Cornstarch Treacle
Starch/Vegetable Starch Ethanol
Corn Oil Free Fatty Acids
Corn Syrup Maize
High Fructose Corn Syrup Zein
Dextrins Sorbitol

Addictive Eating

Another issue that arises with the American diet is addictive eating tendencies. Many people struggle with overeating junk foods that make them feel sick and put them at heightened risk for numerous diseases. Even after people understand the risks of overeating and weight gain, they often have trouble losing weight and cutting back on their eating habits. New research has shown that this may not be our fault; rather, many of our modern foods are addictive.

Research over the last decades has shown that certain pathways in our brain make it possible for us to get addicted to food, specifically sugar, flour, and processed, refined carbohydrates. Animal studies have displayed that animals can get addicted to sugar in their diets. This is why so many people get stuck in a cycle of cutting out sugar, and then eventually binge eating it after just trying to have one small bite. Food addiction is a real condition that causes processes in our brains similar to other types of addictions. Mounting evidence supports the theory that food addiction has a genetic cause, with researchers identifying certain genes that put you at greater risk for developing this condition. The genetic variations that are linked to food addiction, excessive hunger, and lack of satiety can be detected with genetic testing.

Glycemic Load and Impact on Disease Risk

The glycemic load of processed foods, such as sugar and flour, is another reason you should be cautious of overconsumption. Glycemic load tells you how a certain food will affect your blood sugar. It takes into account the glycemic index of food along with the amount of glucose per serving of that particular food. Highly processed foods often have higher glycemic loads, which means that they will cause your blood sugar to quickly rise up. This can have numerous negative health effects.

The good news is there are lots of nutritious foods that have a naturally low glycemic load. While high glycemic load foods can increase your disease risk, low glycemic loads can actually decrease your disease risks. Scientists theorize that you can reduce your risk for obesity, heart disease, type 2 diabetes, and certain types of cancer. Moreover, eating low glycemic load foods may reduce your risk for other diseases that are interconnected to these conditions, such as irritable bowel syndrome and gallstones. Whether or not you choose to remove sugar and gluten from your diet, be sure to incorporate some of these low glycemic load foods so that you can enjoy these benefits.


Food intolerances have the potential to affect all of your bodily systems, making them important to identify as early as possible. Some ways to determine if you have a food intolerance is by doing an elimination diet or by undergoing genetic testing, which can identify if you are suffering from certain intolerances. Whether or not you find that you have a food intolerance, keep in mind the potential risks of eating certain processed foods. Many people can become addicted to these kinds of foods, which can lead to weight gain among other health problems. In addition, many foods that contain sugar and flour have a high glycemic load, which could increase your disease risk and cause blood sugar spikes. Always remember that the food you eat is your fuel for the day, so choose wisely.

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Causes - Lactose intolerance, Staff (NHS) 

Feedgrains Sector at a Glance, Staff (USDA) 

Genetics of Food allergy, Hong, X (Northwestern University Feinberg School of Medicine) 

Glycemic Index and Diet, Staff (Canadian Society of Intestinal Research) 

Lactose intolerance - symptoms and causes, Staff (Mayo Clinic) 

Managing Food Allergies & Diabetes, Staff (Allergy & Environmental Treatment Center) 

Obesity and Overweight, Staff (CDC) 

Sugar Sensitivity - Frequently Asked Questions, Staff (Food Intolerance Institute) 

The lowdown on glycemic index and glycemic load, Staff (Harvard Health Publishing) 

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