Despite available preventive strategies, dental caries remains one of the most widespread chronic diseases in the world. It affects people of all ages — from children with their first baby teeth to seniors — and represents a major burden on healthcare systems. The consequences of untreated caries are serious and go far beyond the mere loss of tooth structure; they include pain, chronic systemic infections, difficulties with eating and sleeping, and reduced overall quality of life. Oral health is not only about preventing cavities; it is a key component of whole-body health.
What will you learn in this article?
- The oral microbiome and its impact on overall health
- How does dental caries develop?
- The impact of sugar consumption on tooth decay
- The protective role of saliva
- Genetic predisposition — are cavities hereditary?
- The influence of systemic diseases and medications
- How to support strong and healthy teeth
- Preventive recommendations
- Key takeaways
The oral microbiome and its impact on overall health
The oral cavity is home to one of the most complex microbial ecosystems in the human body, containing more than 700 species of bacteria, fungi, viruses, and archaea. In a balanced state — called eubiosis — this microbiome is diverse and stable. Microorganisms cooperate and create a natural protective barrier that prevents the overgrowth of pathogens and actively contributes to maintaining oral health.
Oral health is closely linked to overall health — there is a well-documented bidirectional relationship between oral conditions and systemic diseases. Periodontitis, a chronic inflammation of the gums, is associated with a higher risk of cardiovascular diseases, diabetes, rheumatoid arthritis, pregnancy complications, and even Alzheimer’s disease.
This connection is driven by several mechanisms:
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Chronic inflammation: Gum inflammation (gingivitis) and its more advanced form (periodontitis) are chronic infections in which bacteria from the mouth enter the bloodstream. This introduces inflammatory mediators and toxins into the body, which can trigger or worsen systemic inflammation and contribute to the development of several diseases (such as heart and vascular disease, atherosclerosis, or worsened insulin resistance in people with diabetes).
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Bacteremia: During everyday activities such as brushing teeth or chewing, bacteria from dental plaque can enter the bloodstream. In individuals with a weakened immune system, this may lead to serious infections such as infective endocarditis.
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Microbial dysbiosis: Oral bacteria, once swallowed, can influence the composition of the gut microbiome, which subsequently affects immunity and overall health.
How does dental caries develop?
A natural coating — dental plaque — forms on the surface of teeth. It is not just food debris but primarily a living biofilm, a community of bacteria that use sugars from food as their main energy source.
The fundamental mechanism behind tooth decay is that bacteria present in dental plaque metabolise free sugars into organic acids. These acids then disrupt (demineralise) the tooth enamel. Sucrose is particularly cariogenic (promoting tooth decay) because certain bacteria can convert it not only into acids but also into sticky polysaccharides that strengthen plaque structure and create an acidic microenvironment that supports caries formation.
Each intake of sugar therefore causes a drop in oral pH and an increased production of acids. If these episodes occur frequently — for example, through regular sipping of sugary drinks or frequent snacking — the oral environment does not have enough time to neutralise the acids and naturally remineralise the enamel, which significantly increases the risk of tooth decay.
At an acidic pH, demineralisation of the enamel occurs. Enamel is composed of hydroxyapatite crystals (the primary inorganic component of enamel, dentin, and bone, responsible for their hardness and strength). Once the pH drops below the critical threshold of 5.5, minerals begin to dissolve from the enamel surface, weakening it and gradually forming an initial carious lesion — a cavity.
The influence of sugar consumption on the development of tooth decay
The main and best-documented risk factor for dental caries is the consumption of so-called “free sugars.” The World Health Organization (WHO) defines these as all monosaccharides and disaccharides added to foods and beverages, as well as sugars naturally present in honey, syrups, fruit juices, and juice concentrates.
These sugars differ from those naturally bound within the structure of whole fruits and vegetables. The fibre in fruits and vegetables slows the release of sugars and also stimulates saliva production, which reduces their cariogenic potential. Therefore, these naturally bound sugars do not represent the same level of risk for tooth decay.
The protective function of saliva
Saliva is one of the most important protective factors against dental caries — it not only shields the teeth from acid damage but also supports their repair and helps maintain a healthy oral microbiome.
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They neutralise acids — saliva contains buffers (such as bicarbonates) that counteract the pH drop caused by acids produced by plaque bacteria.
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They enable remineralisation — saliva contains minerals such as calcium and phosphate, which help restore enamel and repair early stages of demineralisation.
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They exhibit antimicrobial activity — saliva contains compounds such as lysozyme, lactoferrin, and immunoglobulins that inhibit the growth or directly destroy harmful cariogenic bacteria.
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They provide mechanical cleansing of the teeth — the flow of saliva continuously rinses tooth surfaces and removes food debris and microorganisms. Reduced saliva flow (hyposalivation or xerostomia) dramatically increases the risk of tooth decay.
The quality and quantity of saliva are therefore direct and measurable indicators of caries risk. Malnutrition can negatively affect the function of the salivary glands, creating a vicious cycle in which poor nutrition lowers the natural defence mechanisms of the mouth.
Genetic predisposition — are cavities hereditary?
Genetics play a significant role in susceptibility to dental caries. Research shows that hereditary factors may explain up to 65% of the variation in resistance to tooth decay among individuals. It is important to emphasise that actual cavities are not inherited — only the predisposition to develop them.
Certain genetic variants influence the quality of tooth enamel and the composition and quantity of saliva. Other genes may affect the immune response to oral bacteria, increasing the tendency toward periodontal disease and cariogenic conditions. Genes related to vitamin D and calcium metabolism also play a role in the ability of teeth to resist demineralisation.
From this perspective, some individuals may be naturally more resistant to tooth decay, while others are more susceptible even if they follow proper hygiene and dietary habits. Personalised prevention should therefore consider family history, which may indicate increased genetic risk and the need for more intensive preventive measures.
The influence of systemic diseases and medications on the development of dental caries
Many systemic diseases and medications can increase susceptibility to dental caries:
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Diabetes mellitus: Poorly controlled diabetes leads to higher glucose levels in saliva, providing more fuel for cariogenic bacteria. It is also often associated with reduced saliva flow and weakened immune response, further increasing the risk of caries and periodontitis.
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Reflux: Frequent exposure of teeth to stomach acid causes dental erosion, which weakens enamel and makes it more susceptible to further damage.
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Certain autoimmune diseases: For example, Sjögren’s syndrome directly attacks the salivary and lacrimal glands, leading to severe xerostomia and rapid progression of dental caries.
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Certain medications: More than 500 commonly prescribed medications (including antihistamines, antidepressants, and antihypertensive drugs) have dry mouth as a side effect, which is one of the most significant risk factors for tooth decay.
How to support strong and healthy teeth?
Preventing dental caries does not rely solely on reducing risk factors such as sugar intake — it also involves actively strengthening the natural defences of the teeth. A diet rich in key micronutrients can help slow or even reverse early caries development — even if some sugar is present in the diet. Well-mineralised and strong teeth are far more resistant to acidic challenges and decay.
Key nutrients for dental health
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Vitamin D: Essential for the metabolism of calcium and phosphorus — the two primary building blocks of enamel and dentin. Receptors for vitamin D are present directly in the specialised cells of the teeth (ameloblasts and odontoblasts), responsible for forming enamel and dentin. Vitamin D deficiency can impair mineralisation, making teeth significantly more vulnerable to decay. Some studies even suggest that a mother's vitamin D status during pregnancy may influence her child’s future cavity risk.
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Vitamin K2 (menaquinone): Works synergistically with vitamin D. While vitamin D ensures sufficient calcium levels in the blood, vitamin K2 activates proteins that direct this calcium into bones and teeth and prevent its deposition in soft tissues such as blood vessels. The synergy of vitamins D3 and K2 is essential yet often overlooked.
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Calcium and phosphorus: These are the fundamental components of hydroxyapatite — the primary mineral structure of enamel and dentin. A diet rich in these minerals supports remineralisation and strengthens tooth structure. Saliva is naturally rich in these minerals, helping repair micro-damage and maintain resistance to acids and decay.
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Vitamin A: Essential for maintaining healthy mucous membranes and proper salivary gland function. Vitamin A deficiency commonly leads to dryness of mucous membranes — including dry mouth (xerostomia).
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Vitamin C: Crucial for collagen synthesis, forming the foundation of gingival connective tissues and the organic matrix of dentin. Severe deficiency (scurvy) may manifest as gum inflammation and bleeding.
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Zinc: Essential for proper salivary gland function; low zinc levels are linked to xerostomia, reduced saliva production, and impaired taste perception. It also supports immune function and wound healing, and in the mouth can help reduce gum inflammation.
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Magnesium: Involved in the formation and stability of hydroxyapatite. It also supports remineralisation by aiding the redeposition of minerals into enamel along with calcium and phosphorus.
Preventive recommendations
Effective caries prevention requires a comprehensive approach that considers all factors influencing dental health. The key is combining several strategies that complement one another.
- Appropriate diet: Limiting the intake and, in particular, the frequency of free sugars. A diet rich in calcium, phosphorus, magnesium, vitamins A, C, D, K2, and other micronutrients supports dental health and a balanced oral microbiome.
- Supplementing missing nutrients: Vitamins D and K2 are difficult to obtain in sufficient quantities from diet alone. Magnesium is depleted more rapidly during stress, physical activity, and with caffeine or alcohol intake. Targeted supplementation can support caries prevention.
- Oral hygiene: Regular and thorough plaque removal — brushing twice daily and cleaning interdental spaces.
- Use of fluorides: Fluorides strengthen enamel and support remineralisation. It is important not to swallow fluoride toothpaste. Fluoride use is not recommended for children under 6 years unless advised by a dentist.
- Regular professional care: Routine dental check-ups and hygiene appointments provide early diagnosis, professional cleaning, and personalised recommendations.
Key takeaways
Dental caries
- One of the most common chronic health problems affecting people of all ages.
- Oral health is an important part of overall health.
How tooth decay develops
- Bacteria in dental plaque metabolise sugars into acids → leading to enamel demineralisation.
- Critical pH for enamel: 5.5.
- Frequent consumption of sugary drinks and sugar increases caries risk.
Other factors influencing tooth decay
- Saliva: neutralises acids, enables remineralisation, and has antimicrobial effects.
- Genetics: up to 65% of susceptibility to caries is hereditary.
- Systemic diseases and medications: diabetes, reflux, Sjögren’s syndrome, and many medications increase risk.
Nutritional support for healthy teeth
- Vitamin D: supports calcium and phosphorus metabolism and enamel formation.
- Vitamin K2: works with vitamin D to direct calcium into teeth and bones.
- Calcium, phosphorus, magnesium: essential for enamel and dentin formation and remineralisation.
- Vitamins A and C, zinc: important for healthy saliva, gums, and connective tissues.
Pillars of prevention
- Diet: limiting free sugars, ensuring adequate minerals and vitamins.
- Oral hygiene: brushing twice daily + interdental cleaning.
- Fluorides: strengthen enamel and support remineralisation.
- Professional care: regular check-ups, cleanings, and guidance.
Sources
Malin AJ, Wang Z, Khan D, McKune SL. The Potential Systemic Role of Diet in Dental Caries Development and Arrest: A Narrative Review. Nutrients. 2024;16(10):1463. https://doi.org/10.3390/nu16101463
https://www.who.int/news-room/fact-sheets/detail/sugars-and-dental-caries
Fu D, Shu X, Zhou G, Ji M, Liao G, Zou L. Connection between oral health and chronic diseases. MedComm (2020). 2025;6(1):e70052.
Shodhan Shetty A et al. Role of nutritional supplements on oral health in adults - A systematic review. F1000Res. 2023;12:492.
https://www.researchgate.net/publication/373880285_Effectivity_of_Calcium_Phosphate_and_Vitamin_D_in_Dental_Caries_Prevention
Kim YJ et al. Zn2+ stimulates salivary secretions… Sci Rep. 2019.
Tanaka M. Secretory function of the salivary gland… Acta Otolaryngol Suppl. 2002.
Shaffer JR et al. Genetic susceptibility to dental caries differs between the sexes. Caries Res. 2015.
