Prebiotics and diabetes: Can dietary fibers help manage blood sugar levels?

Many of us know the power of dietary fiber in supporting digestive health. The good news is that it is also found to offer countless benefits for people with diabetes. 

Eating more fiber is beneficial for good digestion, but for people with diabetes, it is much more powerful.

Not only can fiber aid in managing one’s weight by keeping the stomach full, but it can also have a beneficial impact on blood glucose levels.

What are dietary fibers? 

Dietary fibers are also known as roughage or bulk. This includes the parts of plant foods that the body can’t digest or absorb. 

Unlike some other food components, like fats, proteins or carbohydrates that your body can break down and absorb, fiber is not digested by the body.

Instead, fiber just passes relatively intact by the stomach, small intestine and colon, then out of the body. 

Fiber can be classified as soluble, which dissolves in water, or insoluble, which is the opposite. 

Soluble fiber

This type of fiber dissolves in water to make a gel-like material. Soluble fiber is known to aid in decreasing blood cholesterol and glucose levels. It is commonly found in beans, apples, citrus fruits, carrots, barley, oats, peas and psyllium.

Insoluble fiber

This type of fiber promotes the movement of material by the digestive system and increases stool bulk. Hence, fiber can be of benefit to people who struggle with constipation or irregular stools.

Some good sources of insoluble fiber are beans, whole-wheat flour, wheat bran, nuts and vegetables. This also includes cauliflower, green beans and potatoes.

Take note that the amount of soluble and insoluble fibers may vary in different plant foods. So, to acquire a significant amount of health benefits, you should eat a wide variety of high-fiber foods. 

Prebiotics as a type of fiber

In the gut, prebiotics serve as food for beneficial microorganisms or are known as probiotics. Both prebiotics and probiotics can fuel microbiota to grow and assist with digestion.

As a result, they produce substrates that positively impact health, including strengthening immunity and warding off disease

A prebiotic is a type of fiber, but not all fiber is considered a prebiotic. Some examples of prebiotic fibers are fructans and galactooligosaccharides (GOS).  

For a fiber to be classified as a prebiotic, it must pass through the gastrointestinal tract undigested and should be able to stimulate the growth and/or activity of some good bacteria in the large intestine.  

Prebiotic fibers have been gaining popularity in the fitness industry. Many people learned a broader understanding of how beneficial bacteria are in the gut, particularly as prebiotic fibers help support the digestive and immune systems

Many individuals are also increasingly aware of the number of factors affecting the decrease of good bacteria in the gut, such as stress, antibiotics and poor diet, which as a result, may cause bacterial imbalance [1]. 

Why are blood sugar levels crucial in diabetes? 

Why are blood sugar levels crucial in diabetes? 

For people with diabetes, monitoring their blood sugar or glucose is crucial to find out the effectiveness of their current treatment plan. 

The blood sugar level may help diabetic people by providing information on how to manage diabetes every day or sometimes even every hour, especially for people who suffer from diabetes and use insulin.

The results of monitoring blood sugar can help them make decisions about certain food intake, physical activity and dosing insulin.

Furthermore, there are major things that can affect your blood sugar. In fact, you can easily predict some of the impacts with time and practice. Although, some people may find it difficult or impossible to predict. 

Hence, it is important to check your blood sugar regularly if your doctor recommends doing so. The following situations typically increase blood sugar levels:

  • Lack of exercise or getting less activity
  • Eating a lot of carbohydrates
  • The dawn phenomenon refers to an early-morning rise in blood sugar that is likely due to natural fluctuations in hormones like cortisol. 
  • Dehydration
  • Medical condition, surgery or stress
  • Missing a dose or not taking enough diabetes medication or insulin
  • Puberty
  • Smoking
  • Taking corticosteroid (steroid) medications

Some situations that may help lower your blood sugar:

  • Missing meals or fasting
  • Taking high doses of diabetes medication or insulin
  • Exercise or physical activity

On the other hand, some situations can either raise or lower your blood sugar. This depends on certain factors and your distinct biology.

Factors like:

  • Monthly menstruation
  • Food and medication or insulin timing
  • Consuming alcoholic beverages
  • Interactions of non-diabetes medication 

Considering the numerous factors affecting blood sugar levels, checking it is essential for people with diabetes to have an accurate medical course of action. Monitoring is the only way to be informed when your blood sugar levels are changing [2]. 

How can prebiotics help in managing blood sugar levels? 

In recent decades, obesity and diabetes are two of the metabolic diseases that can lead to other major diseases or high risk of death. 

The growing number of people suffering from obesity and diabetes are rapidly increasing over the years. This raises major concerns for health institutions and organizations worldwide. 

Many studies have proven that the composition and dysfunction of the gut microbiota are linked to the development of diabetes.

Given this, different strategies, like the use of prebiotics to improve intestinal microbial structure and function, have become popular.

When the prebiotic carbohydrates can’t be used to change the makeup of microbiota, prebiotics just exert their effects as a dietary fiber.

Dietary fibers can’t be digested in the small intestine and enter the large intestine, and most prebiotic carbohydrates fall within the definition.

Numerous clinical studies reveal the importance of metabolic effects of dietary fiber ingestion, covering many aspects potentially good for type 2 diabetes.

Some of these are: 

  • Energy dilution and increased bulk of one’s diet may lead to a decrease in energy intake
  • Instil sensitizing effects in peripheral tissues from the systemic metabolism of the SCFA acetate and propionate with insulin 
  • The potential of SCFA to promote the release of hormones, such as GLP-1, with effects on appetite and glucose metabolism [3].

Prebiotics are considered non-digestible substances that have a positive physiological effect. It happens by selectively promoting the growth or action of a limited number of indigenous good bacteria in the host.

From the previous decade, there has been high public interest and demand for the development of new products and prebiotic formulas to improve quality of life, including treating type 2 diabetes by activating receptors and microorganism recognition in the intestinal lumen. 

Prebiotics may assume a key role in the treatment of metabolic disorders. For instance, the major potential for intestinal microflora perspective, improvement of insulin sensitivity and reduction of autoimmune response. 

However, deeper extensive research is needed to fully understand whether the administration of probiotics can be proficiently used together with prebiotics for the prevention and treatment of type 2 diabetes [4].

In a research study titled “Prebiotics as a Tool for the Prevention and Treatment of Obesity and Diabetes: Classification and Ability to Modulate the Gut Microbiota” [5], the researchers suggest that consuming prebiotics for modulating the gut microbiota can help in the production of microbial metabolites. 

This includes short-chain fatty acids that play important roles in decreasing blood glucose levels, mitigating insulin resistance, lowering inflammation and boosting the secretion of glucagon-like peptide 1 in a person. Hence, all these benefits can be accounted for by the observed remission of metabolic diseases.

Foods rich in dietary fibers 

Foods rich in dietary fibers 

Blackberries – are considered the best berry for metabolism as their fiber content is the highest among berries, same with raspberries. Research shows that there are more anthocyanins in a plant when it has a deeper color or hue of a plant. This offers more health benefits.

Oats – can provide a double whammy of fiber because of their double-type fiber content: soluble (the oat) and insoluble (the husk) fiber. Meaning oats can help move bulk out of the body and lower cholesterol. 

Research suggests that oats were superior in controlling appetite and weight. Oats don’t contain added sugar that many bowls of cereal have [6]. 

Popcorn – offers plenty of fiber and is one of the highest antioxidant snacks widely available. A research study found that popcorn may contain more antioxidants compared to fruits and vegetables [7]. 

Beans – are considered to be the powerhouses of fiber content. Beans can provide a huge amount of fiber with just a small serving. Also, bean-based noodles like Banza, which contain beans and water, can be a good alternative for people who do not like beans.


For you to increase your daily dietary intake accurately, you may consider taking prebiotic supplements.

Eating certain prebiotic-rich foods with added prebiotics is also a great idea, which is a growing trend to add more to your diet. 

You can also consider grain-based baked foods-everything from bread to cereal or snacks-as they are attractive carriers of prebiotics. Most prebiotic ingredients are plant-derived fibers that complement grain systems.


Photograph: alesha_macarosha/Envato
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