Nutrition and Oral Health: A Comprehensive Overview

Introduction:

Diet and nutrition play pivotal roles in oral health, influencing the onset and progression of various oral conditions like caries, periodontal disease, and erosion. Nutrition encompasses both micronutrients (e.g., vitamins, minerals) and macronutrients (e.g., carbohydrates, proteins, fats) essential for bodily needs, while diet refers to specific food consumption patterns. This interplay is bidirectional, as oral health issues can impede eating abilities.(1)

Various research methodologies, including epidemiological studies, case-control studies, and clinical trials, provide valuable insights into nutrition's impact on oral health. Epidemiological studies, primarily observational, explore associations between nutritional factors and outcomes in large populations, though causation isn't directly proven. Case-control studies compare groups with and without a particular condition to identify potential causative factors. Clinical trials, controlling for more variables, aim to detect statistically significant changes in the variable of interest.(2)

Multiple dietary elements, such as macronutrients, micronutrients, vitamins, and pH properties, along with associated consumption behaviors, influence oral health. Factors like developmental stage, medical conditions, and socioeconomic status also warrant specific dietary considerations.(3) For instance, older adults may face challenges like tooth loss, reduced chewing ability, and decreased appetite, impacting their nutritional status. A systematic review investigating food intake and oral health in the elderly revealed a correlation between tooth loss, altered food intake, and nutritional deficiencies.(4)

Dental Caries:

Dental caries is a microbiological disease of the calcified tissues of the teeth, characterized by demineralization of the inorganic component and destruction of the organic content of the tooth. It is one of the oldest and most frequent illnesses affecting the oral cavity. Age, sex, ethnicity, food habits, and dental hygiene practices are some of the risk variables that affect the prevalence and incidence of dental caries in a community.

The prevalence of this disease is reducing in affluent countries, whereas it is slowly increasing in many developing countries.(5) India, a developing country, presents numerous obstacles in providing oral health care. The majority of India's population lives in rural areas, with children accounting for more than 40%. The prevalence of dental caries in 5- and 12-year-old children in India has been observed to be low (50% and 52.5%, respectively) when compared to many other countries of Asia.(6)

Many industrialized countries have seen a significant reduction in dental caries, which can be linked to improved socioeconomic situations, changing lifestyles, self-care practices, fluoride use, and water fluoridation, as well as effective utilization of preventative oral health services. Behavioral practices are widely mentioned in the oral health literature, indicating that majority of dental illness is avoidable. Good dental hygiene protects against harmful bacteria that could cause oral disease. Maintaining good oral hygiene reduces the need to treat dental disorders.

Role of carbohydrate in caries:

Caries and carbs have a well-established relationship: bacteria in biofilm (dental plaque) create acidic byproducts that demineralize dental hard tissues through fermentation of dietary carbohydrates.Six More precisely, when carbohydrates are consumed, the pH of the tooth biofilm rapidly drops (to 5.5 or below).(7) In addition to causing tooth demineralization, this lower pH can also alter the balance of bacteria in the biofilm, increasing the number of acidic biofilm species. Thus, eating a lot of carbohydrates plays a significant nutritional role in the development of caries.(8)

Types of carbohydrates

The correlation between carbohydrates and dental caries hinges on the specific type of carbohydrate consumed, whether it's sugars or starches, as the cariogenic potential, meaning its ability to promote tooth decay, is contingent on how efficiently bacteria ferment it.(9) Sugars, in particular, stand out as primary drivers of caries development. Free sugars encompass all sugars added to food or beverages, including those naturally occurring in fruit juices, concentrates, honey, and natural syrups. These sugars, whether natural or free, such as sucrose, glucose, and fructose, are deemed crucial factors in caries formation.(10) Among them, sucrose, a disaccharide of glucose and fructose, holds the highest cariogenicity. Sucrose serves as a substrate for synthesizing intra- and extracellular polysaccharides in dental plaque. Moreover, dental plaque formed in the presence of sucrose tends to exhibit lower concentrations of calcium, inorganic phosphate, and fluoride, essential ions for enamel and dentin remineralization. Compared to starches, sucrose and its constituent monosaccharides, glucose and fructose, pose greater cariogenic risks due to their rapid entry into the glycolytic pathway, resulting in a more pronounced pH drop. Although lactose is also a sugar, its fermentation yields a smaller pH drop than sucrose, fructose, and glucose, rendering it less cariogenic.Top of Form(11)

The quantity and frequency of sugar intake

The amount of sugar consumed may have an impact on the development of caries in addition to the kind. A systematic review conducted in 2014 looked at the impact of free sugar consumption on dental caries and found a consistent link between free sugar intake and the development of caries. Populations with free sugar intakes exceeding 10% of total energy intake were found to have higher caries incidences than those with intakes below 10%.(12) The World Health Organization's (WHO) recommendations for sugar intake are based on this systematic review, and they advocate consuming less than 10% of total calorie intake from free sugars, with a further reduction to fewer than 5% being suggested.(13)

Frequency, or how often free sugars are consumed, may also influence caries development. More frequent sugar consumption and snacking between meals are thought to be more important in predicting caries risk than overall sugar consumption.(14) One probable explanation for this concept is because it takes around 30 minutes for the pH to drop after consuming sugar, therefore extra sugar intake during that 30-minute period is less dangerous than additional intake after 30 minutes. However, because the two are so closely connected, determining the relative impact of sugar quantity and frequency to dental caries risk is difficult.(15)

Recent systematic reviews and guidelines, as referenced above, provide compelling data supporting the correlation between sugar consumption and/or snacking and the development of dental caries.(16) While these findings do not establish causality, they consistently demonstrate that increased intake of free sugars is linked to a higher risk of caries.

Efforts to reduce the consumption of sugar-sweetened beverages (SSBs), which significantly contribute to free sugar intake, are ongoing. One proposed strategy is the implementation of a tax on SSBs, with studies suggesting that such taxation could decrease SSB consumption, caries incidence, and associated costs. Although public acceptance and efficacy of this approach are still uncertain, a 2019 systematic review and meta-analysis revealed that a 10% tax on SSBs was associated with an average decrease in SSB purchase and intake by 10.0%. Additionally, there is a need for rigorous evaluations with long-term study designs to assess the effectiveness of interventions at the population level.(17)

Early childhood caries (ECC), defined as the presence of decayed, missing, or filled tooth surfaces in children under 6 years old, is primarily caused by prolonged exposure to sweetened liquids. To combat ECC, both the Academy of Nutrition and Dietetics and the American Academy of Pediatrics advocate for limiting fruit juice consumption among babies and toddlers.(18)

Socioeconomic factors such as limited income and access to nutritious foods can exacerbate the risk of caries and other oral diseases. Low-income populations may experience inadequate intake of nutrient-dense foods, coupled with lower health literacy and restricted access to oral healthcare.(19)

Certain foods like milk, dairy products, apples, cranberries, tea, and high-fiber foods are believed to possess cariostatic properties, potentially inhibiting the development of caries. For instance, calcium in dairy products may counteract some cariogenic effects by limiting enamel undersaturation during acidogenesis. Studies investigating the association between milk consumption and caries suggest that milk intake does not elevate caries risk and might even reduce it.(14)

Sugar alcohols like xylitol and sorbitol, commonly used in chewing gums and artificial sweeteners, have been proposed to have cariostatic effects, although findings are inconclusive. These compounds may substitute fermentable carbohydrates, reduce acidogenic potential, inhibit the growth of plaque bacteria like Streptococcus mutans, or stimulate salivary flow. However, the American Dental Association (ADA) has not established a policy regarding the use of xylitol for caries prevention, citing low-quality evidence of its benefits as adjunctive therapy in high-risk individuals.(20)

Periodontitis, as defined by the American Academy of Periodontology, is characterized by inflammation of the periodontal tissues, resulting in clinical attachment loss, alveolar bone loss, and periodontal pocketing.(21) This condition is instigated by specific microorganisms within dental plaque, triggering an excessive host response that leads to progressive damage to the tooth-supporting structures, including the gingiva, periodontal ligament, and alveolar bone. The influence of nutritional status on the body's immune response may potentially modify factors relevant to the management of periodontal disease. However, due to the multifactorial nature of periodontal disease and nutritional status, elucidating such effects proves challenging.(22)

In comparison to studies on dental caries, research exploring the relationship between nutrition and periodontal disease is relatively limited. Existing studies investigating the link between nutrition and periodontal disease have predominantly focused on the consumption of lipids and various micronutrients.(23) Nevertheless, systematic reviews examining the impact of dietary minerals and lipids on the onset, severity, progression, and treatment of periodontal disease have yielded insufficient evidence to establish any significant associations.(23)

Dental erosion:

Dental erosion is characterized clinically as the gradual and irreversible loss of dental hard tissue resulting from a chemical process of acid dissolution, excluding bacterial involvement.(24) While acid reflux and certain medications can contribute to erosive tooth wear, dietary factors stand out as the primary source of acid exposure leading to erosion. Specifically, the frequency and patterns of acidic food or beverage consumption, along with the duration of contact with teeth, play significant roles in influencing erosive tooth wear.(25) However, it's important to note that the pH level alone does not solely determine the erosive potential of a food or beverage. Both pH and buffering capacity collectively dictate the erosive nature of a substance. For instance, yogurt, despite having a pH of around 4.0, is not considered erosive due to its high calcium content, which acts as a buffering agent.(26)

A meta-analysis conducted in 2012 revealed that soft drinks and chewable vitamin C tablets were associated with the development of erosive tooth wear, while juice, sports drinks, milk, and yogurt did not exhibit such associations. However, findings from a 2015 meta-analysis painted a somewhat different picture, indicating that soft drinks, acidic snacks, and fruit juices increased the odds of tooth erosion in children. Interestingly, this analysis also found that the intake of milk and yogurt was linked to a reduction in the occurrence of erosion.(27)

Calcium intake:

Calcium, a vital mineral present in various foods, plays a crucial role in the formation and maintenance of healthy bones and teeth, including the primary calcium phosphate mineral, hydroxyapatite, found in bone and enamel.(28) Dietary calcium is absorbed from the intestine into the bloodstream, primarily sourced from human or animal milk, dairy products like cheese and yogurt, or foods fortified with calcium as per eCFR §104.20 guidelines. According to the 2015-2020 Dietary Guidelines for Americans, children aged 1-3 years are recommended to consume 700 mg of calcium per day, while children aged 4-8 years should aim for 1000 mg daily.(29)

In the United States, approximately 72 percent of calcium intake is derived from dairy consumption and products with added dairy content. However, there is a burgeoning market for plant-based milk alternatives made from soy, almonds, oats, nuts, potato, flaxseed, or hemp, which often come fortified with various nutrients, including calcium.(30) Despite this, a technical report from national health and nutrition organizations advises against the consumption of plant milks or non-dairy beverages for infants aged 0-12 months. Additionally, unsweetened plant milks other than soy milk are not recommended as exclusive substitutes for dairy milk.(31)

Other Oral Health Conditions

Oral and Oropharyngeal Cancer

Oral and oropharyngeal cancer presents a significant concern, particularly given its association with heavy alcohol consumption, which notably increases the risk of developing this type of cancer. Apart from this link, there hasn't been a direct correlation between diet and the risk of oral and oropharyngeal cancer, beyond generalized observations.(32) However, similar to findings in other cancers, there is a suggestion that the consumption of fruits and vegetables may offer protective benefits. A meta-analysis demonstrated a lower risk of oral cancer in individuals with increased fruit and vegetable intake, while a large prospective observational study further supported this notion by associating total fruit and vegetable consumption with a reduced risk of head and neck cancer.(33)

Aphthous Ulcers

Recurrent aphthous stomatitis (RAS), commonly known as canker sores, poses challenges in understanding its dietary management due to a scarcity of robust studies. Reported dietary triggers for RAS include the consumption of hard, acidic, and salty substances, along with alcoholic and carbonated beverages.(34) While the role of diet in RAS management remains underexplored, preliminary evidence indicates a potential link between zinc deficiency and RAS. Studies suggest that zinc deficiency is more prevalent in individuals with RAS compared to those without, and supplementation with zinc has shown promise in improving RAS resolution among individuals deficient in this mineral.(35)

Xerostomia

Xerostomia, commonly known as dry mouth, can significantly impact oral health and overall quality of life, with dietary factors potentially exacerbating its effects. Foods that are dry or acidic, along with consumption of caffeine and alcohol, may contribute to the discomfort and complications associated with xerostomia.(36)

Discussion:

A significant focus of the article is on the role of dietary carbohydrates, particularly sugars, in the etiology of dental caries. It delineates how the type, quantity, and frequency of sugar consumption significantly influence the risk of caries development. Moreover, potential strategies, such as taxation on sugar-sweetened beverages, are discussed as means to reduce sugar intake and mitigate caries incidence, especially among vulnerable populations like children.

Furthermore, the article explores the association between nutrition and other oral health conditions, including periodontitis, dental erosion, and xerostomia. While evidence on the role of diet in these conditions is limited, dietary factors such as acidic foods and beverages are identified as potential exacerbating factors. This underscores the importance of dietary counseling and lifestyle modifications in managing oral diseases holistically.(37)

Additionally, the article underscores the significance of preventive measures, such as limiting fruit juice consumption in early childhood to prevent early childhood caries, and promoting a balanced diet rich in fruits, vegetables, and dairy products to enhance overall oral health.(38)

Conclusion

The intricate relationship between diet, nutrition, and oral health, highlighting the significance of a comprehensive approach to oral care that includes dietary guidance in dental practice and public health efforts. It urges for more research to better understand the mechanisms that underpin the relationship between diet and oral health, as well as to develop targeted medicines for effectively preventing and managing oral illnesses. Finally, developing healthy food habits and controlling sugar consumption are crucial for improving dental health outcomes and community well-being at large.

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