The human body has a variety of microbiomes, the largest and second-largest being the gut and oral cavity, respectively. These microbiomes exist in a complex relationship with one another. The bacteria that cause gum disease and tooth decay, for example, may travel to the gut
microbiome and affect change there.
Since our overall health is impacted by our gut health, and our oral health can impact the gut, it goes to follow that our oral health is a factor in our general wellbeing. If your microbiomes fall out of balance, there may be health issues throughout the body.
Prebiotics help to encourage healthy bacteria in our oral and gut microbiomes, but how do they accomplish this?
What are Prebiotics and How Do They Work?
Prebiotics exist naturally in the foods we eat, and once consumed, help promote the growth of healthy bacteria in our bodies. Prebiotics are substrates, which are essentially molecules upon which an enzyme can act, and they are used by the host organism in a manner which promotes health. They resist digestion and thus can pass through the stomach and small intestines into the colon where they begin to ferment, increasing the number of healthy bacteria.
Many prebiotics are classified as dietary fibre, though not all fibres are considered prebiotics. Insoluble fibre, for example, is not considered a prebiotic, as it helps to move food quickly through the stomach and intestines to keep you regular. It ferments poorly and is therefore not considered a true prebiotic.
Various types of soluble fibre are among the most-studied prebiotics. These include inulin, fructooligosaccharides, and galactooligosaccharides. Water causes soluble fibre to break down and form a gel-like substance which acts to slow digestion. Other fibres which can be fermented by our gut bacteria include resistant starches and beta-glucans. Since there are too many prebiotics to list here, the general rule of thumb is that a soluble fibre will be considered a prebiotic.
Some other prebiotics have been identified recently which are not types of fibre. These include long-chain omega-3 fatty acids found in fish (EPA and DHA) and polyphenols found in tea and fruits. Some other sources of prebiotics include:
- Fructans are found in bananas, onions, asparagus, and garlic contain inulin and fructooligosaccharides
- Galactooligosaccharides are found in lentils, beans, broccoli, and chickpeas
- Beta-glucan is found in mushrooms, oats, barley, and seaweed
- Polyphenols are present in berries and other fruits, broccoli, spinach, dark chocolate, and red wine
- Resistant Starches can be found in green bananas, plantains, beans, seeds, peas, and cold oatmeal
- Omega-3 Fatty Acids exist in fatty fish, such as tuna, trout, salmon, and herring
The Effect of Prebiotics on the Oral Microbiome
The definition of prebiotics has changed over the years. Originally not broad enough, it did not include those which modified microbiomes other than the gut. Today’s definition now includes
every microbiome in the body.
Some compounds which are not naturally found in foods have come to be considered prebiotics due to their ability to increase healthy bacteria while reducing pathogenic species. Arabinose and xylitol are two examples, capable of stimulating the growth of certain lactobacilli that help to inhibit pathogens related to dental caries, gum disease, and candidiasis.
It is possible that in the future, prebiotics may be added to such products as toothpaste and mouth rinses, gum, and more. It will be necessary to find a way to keep the prebiotics in the mouth long enough to allow for fermentation. Currently, mints and gum accomplish this with xylitol. To be effective, 5 to 7 g are recommended in multiple doses throughout the day. This would require the chewing of 2 pieces of gum following breakfast, lunch, and supper. This is simple to accomplish, but it may result in issues such as diarrhea, gas, and bloating.
In What Other Ways Do Prebiotics Relate to Oral Health?
Research is still being conducted on the effects of oral prebiotics, but we can examine their effectiveness on oral health in indirect ways. For example, P. ginigvalis is a pathogen that is indicated in gum disease, or periodontitis and which has also shown the ability to create an imbalance in the gut microbiome that is frequently associated with disease. It can be found in those suffering from obesity, metabolic disorders, and cardiovascular disease. When prebiotics are administered, the overall result is improved overall metabolic health.
Evidence also points to the role of the gut microbiome in gum disease, with one study revealing that those with gum disease possessed a less diverse gut microbiome than those with healthy gums. Periodontitis is a chronic inflammatory disease. Knowing that it is related to imbalances in gut bacteria, the question naturally arises as to how improving the gut microbiome might affect oral health.
Type 2 diabetes and obesity are both known risk factors for gum disease and are associated with chronic inflammation. Prebiotics may help with these diseases by improving insulin resistance and thus assisting with weight loss. Prebiotics can therefore be considered a factor in preventing periodontal disease, as it reduces the risk factors associated with type 2 diabetes, obesity, and chronic inflammation.
It is not presently known how altering our gut microbiome can directly affect our oral health, but obesity and other conditions which affect oral health are related to systemic disease, and systemic health can be improved by improving the gut microbiome.
How Do Prebiotics Impact Our Health?
Prebiotics may cause several effects, all of which are too numerous to effectively detail here, but there are some general means in which they affect our health, including:
- Leaky Gut
When harmful substances are able to pass through the intestinal wall, this is known as “leaky gut” and can be the result of P. ginigvalis altering the gut microbiome. This results in a greater number of toxins entering the bloodstream, leaving the body more susceptible to inflammation. Short-chain fatty acids produced by prebiotics during fermentation strengthen the intestinal wall, helping to contain the harmful bacteria.
- Weight Loss
The feeling of being full, referred to as satiety, is triggered by hormones. Prebiotics may influence the release of these hormones, causing one to eat less. Fructooligosaccharides have been shown to increase the concentration of hormones controlling appetite. By assisting in weight control in this manner, prebiotics can reduce the risk of periodontal disease which is related to obesity.
- Controlling Blood Glucose
Those with uncontrolled blood glucose levels are at a higher risk of gum disease. It is a reciprocal relationship, with periodontal disease affecting blood glucose levels. Prebiotics can reduce the risk of periodontal complications and diabetes by modifying the gut microbiome in a manner which assists with insulin control.
- How to Increase you Prebiotic Intake
Since a variety of dietary fibres are considered prebiotics, increasing your intake of these fibre will increase your prebiotic intake. In Canada, the recommended daily intake of fibre is 25g for women and 38g for men aged 19 to 50. Many do not achieve this level, however.
Here are some foods to consume to increase your daily intake of fibre:
1 cup of cooked broccoli (4 g of fibre)
1 serving of oatmeal (4 g of fibre)
1 tbsp of chia seeds (5 g of fibre)
1/4 cup of almonds (4 g of fibre)
1 cup quinoa (6 g of fibre)
1/2 cup of lentils (8 g of fibre)
1/2 cup of raspberries (4 g of fibre)
The current recommendations of the Canadian Food Guide include consuming more plant-based proteins, vegetables, fruits, and whole grains to increase the intake of fibre. It is recommended that each meal be 25% plant-based proteins, 25% whole grains, and 50% fruits and vegetables. There are at present no guidelines on the intake of prebiotics.
Prebiotics occur naturally in certain foods but may be added to others to replace sugar and/or fat. This is common in processed foods such as cereal and baked goods. The addition of these prebiotics are not an indication that these foods are automatically healthy, however. The consumption of whole foods is preferable to processed ones as they lack the fat, salt, and sugar found in most processed foods while also containing a greater number of vitamins and minerals.
Over-the-counter supplements also exist and are used by those who lack sufficient prebiotics in their diets. These supplements can cause side-effects such as diarrhea and gas, however, so it is recommended to start with small doses and gradually increase the quantity as the body becomes accustomed to them.
When increasing the intake of prebiotics through the addition of fibre, be sure to also increase consumption of water, as fibre traps water with it as it moves through the digestive system.
Key Points to Remember:
- Follow Canada’s food guide recommendation of each meal consisting of fruits and vegetables (1/2 of the meal), plant-based proteins (1/4 of the meal), and whole grains (1/4 of the meal) to increase the intake of prebiotics
- Consuming more whole foods increases prebiotic intake
- Non-fibre sources of prebiotics, including polyphenols (berries and tea) and omega-3 fatty acids (fish oil), offer additional options
- Prebiotic supplements help in achieving your daily intake when you find it difficult to get enough through diet alone. Start with small doses, and gradually increase. Alternatively, split the dosage into smaller doses through the day
- Increase your intake of fluids as you increase your fibre intake
- Increasing your prebiotic intake may help prevent oral caries and gum disease by improving systemic health