Dietary interventions and nutritional impact on oral health and development: a review

Abstract

Food and nutrients play a pivotal role in the development of dentition and oral health. While diet includes the overall forms of consumed foods, the nutrients include specific micro- (vitamins and minerals) and macro- (carbohydrates, proteins, and lipids) nutrients. As much as the assimilation of macro and micronutrients depends on proper oral health for ingesting food, oral health, in turn, depends on the availability of nutrients in the food so ingested. Age, certain medical conditions, socioeconomic status, and overall changes in the evolution of society determine the type of diet which in turn influences oral health. This article has touched upon certain salient aspects of these nutrients and their bearing on overall oral health and development.

Introduction

Various environmental factors influence the development of dentition and oral health. Food and nutrients play a very important role in this aspect. Diet has both favorable and detrimental effects on oral health as in, an excess of or a lack of certain nutrients can affect the overall development and sustenance of human dentition. While diet includes the overall forms of consumed foods, the nutrients include specific micro- (vitamins and minerals) and macro- (carbohydrates, proteins, and lipids) nutrients. The influence of diet on the development of dentition depends upon the timing, whether there is an early or late nutritional imbalance (Scardina and Messina 2012). Age and gender are significant factors, as age-related changes in the dentition, such as poor periodontal health and tooth loss, result in dietary changes, and certain nutrient requirements becoming more important in relation to a particular gender at a certain age. Medical conditions and socioeconomic status also determine the type of diet which in turn influences oral health. Finally, the change in food patterns owing to overall changes in the evolution of society like fast foods, frozen, canned, and packaged foods need to be taken into consideration while evaluating the influence of diet on oral health and development (Chi et al. 2015). Keeping all the above factors in mind, we review various nutrients in this article and their influence on oral health and development. The causal association between dietary nutrition and oral health resources can facilitate collaborative research and education in the fields of food science and dentistry (Touger-Decker and Mobley 2013).

Micro-nutrients

Vitamins

Vitamins have a significant effect on oral as well as general health. This relationship is bidirectional in nature, where, deficiency of vitamins can cause tooth or tissue degradation, and tooth loss or oral disorders can result in changes in dietary choice leading to vitamin imbalance (Cagetti et al. 2020). Fat-soluble vitamins (A, D, E, and K) are stored in the liver and fatty tissues and can easily accumulate to toxic levels when taken in excess, whereas, Water-soluble vitamins (B-complex and C) are not stored in the body and can go into deficiency if not regularly replenished in the diet. Hence, understanding the functions, deficiency manifestations and recommended daily allowances and balancing the vitamins in the diet becomes a necessity (Table 1).

Table 1.

Sources, recommended dietary allowances and functions of micro–nutrients and their effects on oral health

Nutrients			Sources	RDA*	Functions	Effects on Oral Health
Vitamins	Fat-soluble vitamins	A	Yellow and orange fruits and vegetables, Milk and milk products	1000 ug/d	Vision, Healthy skin and mucous membrane, Bone and tooth growth, Immune system	Delayed or abnormal cranial and dental development, Impaired wound healing
		D	Egg yolks, Fatty fish, Human skin exposure to sunlight	600 IU/d	Bone and tooth development and mineralization	Hypomineralization of bone and teeth, Impaired growth, Delayed teeth eruption, Absence of lamina dura, Osteoporosis
		E	Vegetable oils, Nuts, Green leafy vegetables, Egg yolks	10 mg/d	Anti-oxidant, Wound healing	Impaired wound healing
		K	Cruciferous and green leafy vegetables, Intestinal bacteria	55 ug/d	Clotting mechanism	Bleeding gums
	Water-soluble vitamins	B1 (Thiamine)	Legumes, Nuts, Grains	1.8 mg/d	Nerve function, Energy metabolism	Recurrent aphthous stomatitis, Impaired postnatal amelogenesis, Cheilitis
		B2 (Riboflavin)	Milk and milk products, Green leafy vegetables	2.5 mg/d	Healthy skin and mucous membrane, Energy metabolism	Cheilitis, Ulcerative gingivitis, Fissured and magenta-colored tongue
		B3 (Niacin)	Meat, Fish, Poultry, Vegetables	18 mg/d	Healthy skin and mucous membrane, Energy metabolism, Nervous system	Cheilitis, Glossitis, Angular stomatitis
		B5 (Pantothenic Acid)	Abundant in most foods	5 mg/d	Energy metabolism	Non-specific
		B6 (Pyridoxin)	Meat, Fish, Poultry, Vegetables	2.4 mg/d	Energy metabolism, Red blood cell formation	Severe gingivitis, Soreness and discoloration of the tongue, Halitosis, Cheilitis
		B8 (Biotin)	Abundant in most foods, Intestinal bacteria	30 ug/d	Energy metabolism	Non-specific
		B9 (Folic Acid)	Green leafy vegetables, Legumes, Liver	300 ug/d	DNA synthesis, Red blood cell formation	Birth defects like oro-facial clefts
		B12 (Cobalamin)	Found only in animal products like Meat, Fish, Poultry, Milk and milk products	2.2 ug/d	Protein and lipid synthesis, Healthy skin and mucous membrane, Nervous system	Redness and burning of the tongue, Atrophy of the papillae, Angular stomatitis, Dysphagia
		C	Found only in vegetables and fruits, especially citrus fruits	80 mg/d	Wound healing, Collagen regulation, Anti-oxidant, Formation of bone, dentine and cartilage	Impaired wound healing, Bleeding gums, Irregular dentin formation
Minerals	Macrominerals	Sodium	Table salt, Soy sauce, Processed foods	2000 mg/d	Fluid balance, Nerve transmission, Muscle contraction	Non-specific
		Chloride	Table salt, Soy sauce, Processed foods	1800 mg/d	Fluid balance, Acid regulation	Non-specific
		Potassium	Meats, Milk, Bananas, Tomatoes, Legumes	3750 mg/d	Fluid balance, Nerve transmission, Muscle contraction	Non-specific
		Calcium	Milk and milk products, Green leafy vegetables	1000 mg/d	Bone and tooth development and mineralization, Nerve transmission, Muscle contraction, Clotting mechanism	Hypomineralization of bone and teeth, Osteoporosis, Increased risk of periodontal diseases, Pitting enamel
		Phosphorus	Milk, Fish, Poultry, Legumes, Nuts	600 mg/d	Bone and tooth development and mineralization, Acid–base balance
		Magnesium	Legumes, Nuts	440 mg/d	Bone development, Nerve transmission, Muscle contraction
	Trace elements	Iron	Green leafy vegetables, Liver, Soybeans	19 mg/d	Oxygen transport as part of hemoglobin, Energy metabolism	Burning and redness of the tongue, Angular stomatitis, Dysphagia, Pallor
		Zinc	Meat, Fish, Poultry, Vegetables	17 mg/d	Enzymatic functions, Growth, Immune system, Wound healing, Fetal development, Taste perception	Loss of taste due to papillary atrophy, Loss of appetite, Xerostomia, Susceptibility to secondary infections
		Iodine	Seafoods, Iodized salt	140 ug/d	Growth regulation, Metabolism	Non-specific
		Selenium	Seafoods, Meat, Grains	40 ug/d	Anti-oxidant	Non-specific
		Copper	Legumes, Nuts, Liver, Water	1.7 mg/d	Enzymatic functions	Non-specific
		Manganese	Legumes, Nuts, Grains	4.0 mg/d	Enzymatic functions	Non-specific
		Fluoride	Water, Fish, Tea	10 mg/d	Bone and tooth development and mineralization, Caries prevention	Fluorosis with mottled and discolored teeth and deformed, stiff and painful bones and joints
		Chromium	Nuts, Liver, Cheese	200 ug/d	Blood glucose regulation	Non-specific
		Molybdenum	Legumes, Nuts, Green leafy vegetables, Liver	45 ug/d	Enzymatic functions	Non-specific

*RDAs (Recommended Dietary Allowance) in this table are representative values obtained from Indian Council of Medical Research (ICMR)—National Institute of Nutrition report on Nutritional Requirements for Indians—2020. The values may differ based on age, gender, lifestyle and other physiological conditions. Further reference is suggested for specific indications. https://www.nin.res.in/RDA_short_Report_2020.html (Accessed 8th October 2021)

Vitamin A

Multiple animal studies have demonstrated that prenatal as well as maternal vitamin A deficiency leads to delayed or abnormal cranial and dental development (Baume et al. 1972; Dinnerman 1951). Vitamin A also plays a part in the overall health of oral epithelium and periodontium (Schneider 1965).

Vitamin D

The contribution of vitamin D to oral health is very significant because it influences both tooth and bone development and mineralization. Vitamin D and its metabolites have antiproliferative, prodifferentiative, and immunomodulatory effects in the human body (Seminario and Velan 2016). Vitamin D supplementation during pregnancy was found to reduce enamel defects in the offspring (Nørrisgaard et al. 2019). Vitamin D induces genomic effects in odontoblasts and ameloblasts and influences the formation and mineralization of hydroxyapatite crystal structure by stimulating the absorption of calcium and phosphate (Dodhia et al. 2021). Anti-caries effects of vitamin D are also well established and are attributed to its stimulation of the production of antimicrobial peptides effective against bacteria in tooth biofilm and its influence on salivary secretion (Youssef et al. 2011; Scardina and Messina 2012). There is an association seen between low prenatal or childhood levels of 25-hydroxyvitamin D (25(OH) D) and dental caries experience in children (Carvalho Silva et al. 2020). Vitamin D plays a vital role in the success of dental implant osseointegration owing to its effect on skeletal bone density and periodontium (Martelli et al. 2014).

Vitamin E

The deficiency of vitamin E is very rare in human beings. Vitamin E plays an important role in tissue regeneration and has positive effects on periodontal healing when used as supplements (Singh et al. 2014).

Vitamin K

The effects of vitamin K on oral health are not as clear as those of other vitamins. However, a deficiency of vitamin K can affect the clotting mechanism by affecting the production of vitamin K-dependent clotting factors (II, VII, IX, and X) in the liver. This can result in an increased risk of hemorrhage in individuals undergoing oral surgery and manifest in the oral cavity with spontaneous gingival bleeding (Gutierrez and Martinez-Mier 2020).

B-Complex vitamins

Eight compounds essential for cell metabolic activity including, B1 (Thiamine), B2 (Riboflavin), B3 (Niacin), B5 (Pantothenic acid), B6 (Pyridoxin), B8 (Biotin), B9 (Folic acid), and B12 (Cobalamin) are grouped together as B-Complex vitamins. B-complex vitamin toxicity is rare because they are not stored in the body, whereas deficiency is quite common due to their need to be replenished in daily diet. This deficiency often results in various oral manifestations. Thiamine deficiency causes beriberi and neurodegenerative disorders like Wernicke encephalopathy. Oral manifestations of thiamine deficiency include recurrent aphthous stomatitis and impaired postnatal amelogenesis, especially in children (Moskovitz et al. 2017; Haisraeli-Shalish et al. 1996). Riboflavin is essential for the metabolism and symptoms of its deficiency include cheilitis and angular stomatitis, fissured and magenta-colored tongue, and recurrent aphthous ulcerations (Cavalcoli et al. 2017). Niacin in its coenzyme forms nicotinamide adenine dinucleotide and nicotinamide adenine dinucleotide phosphate plays a role in oxidation–reduction reactions. Deficiency of niacin causes pellagra characterized by 3 Ds—Dermatitis, Diarrhea, and Dementia. Oral manifestations of niacin deficiency are similar to that of riboflavin and include cheilitis, glossitis, and angular stomatitis (Thomas and Mirowski 2010).

Oral manifestations of Pantothenic acid deficiency are similar to those found in deficiency of other B-complex vitamins (Palmer and Boyd 2016). Adults with Pyridoxine deficiency have demonstrated gastrointestinal disturbances, scaling of the skin, and oral epithelial changes which include severe gingivitis, soreness and discoloration of the tongue, halitosis, and cheilitis (Hodges et al. 1962). Deficiency of Biotin and Pantothenic acid along with low levels of Folic acid have been seen to be associated with orofacial clefts in animal studies (Watanabe et al. 1995). Maternal folic acid supplementation is routinely recommended to reduce the risk of cleft lip and palate (Wilcox et al. 2007; Kelly et al. 2012). Cobalamin deficiency can lead to megaloblastic anemia, neuropathy, myelopathy, skin and nail pigmentations. Intraorally vitamin B12 deficiency is found to be associated with redness and burning of the tongue and atrophy of the papillae, angular stomatitis, and dysphagia (Thomas and Mirowski 2010).

Vitamin C

Collagen synthesis is essential for the health of gingival and periodontal connective tissue. Vitamin C plays an important role in collagen synthesis by increasing the transcription of procollagen genes. Vitamin C deficiency causes Scurvy, with clinical features including follicular hyperkeratosis, petechiae, ecchymosis, inflamed and bleeding gums, joint effusions, and impaired wound healing due to reduction in neutrophil chemotaxis. Scurvy also affects bone by impairing connective tissue matrix and osteoblasts, leading to compromised overall periodontal health (Alagl and Bhat 2015).

Minerals

The essential minerals the body needs are divided into major or macro minerals and trace elements or microminerals based on their dietary requirement. A balanced diet must aim to provide these requirements adequately. These minerals are also essential for oral health owing to their importance in enzymatic action in many chemical and biological reactions.

Calcium, along with Magnesium and Phosphorous forms the major component of bones and teeth. Hydroxyapatite crystals found in tooth enamel are made up of calcium phosphate molecules and calcium is also a critical component of dentin and surrounding extracellular matrix. Calcium is essential for tooth mineralization and plays an important role in the regulation of tooth formation. Calcium and Magnesium are also essential for muscle contraction, nerve conduction, and a healthy immune system (Palmer and Boyd 2009). Vitamin D plays an important role in the regulation of these minerals. Hypocalcemia can lead to bone fragility and hypomineralization of teeth, resulting in osteoporosis and generalized tooth decay. The deficiency of these minerals can also increase the risk of periodontal disease (Nishida et al. 2000). Fluoride has a double-edged effect on teeth and bone. While adequate fluoride intake strengthens bone and enamel and makes them more resistant to demineralization, excess or fluoride toxicity results in a condition called fluorosis with mottled and discolored teeth and deformed, stiff and painful bones and joints. Iron being a critical component of hemoglobin is essential for oxygen transport. Iron is also essential for immune function and a cofactor with vitamin C in collagen production (Thomas and Mirowski 2010). Iron deficiency anemia either isolated or part of Plummer—Vinson syndrome commonly manifests in the oral cavity as burning and redness of the tongue, angular stomatitis, dysphagia, and pallor. Zinc acts as an enzymatic cofactor for cell growth and reproduction, metabolism, stabilization of DNA and RNA, and collagen synthesis (Thomas and Mirowski 2010). Zinc deficiency can cause loss of taste due to papillary atrophy, loss of appetite, and xerostomia. These can contribute to malnutrition and secondary infections (Palmer and Boyd 2016). Other minerals include Sodium, Chloride, and Potassium important for fluid balance, and Iodine, copper, Selenium, and Manganese important for growth and enzymatic action. Though deficiency of these minerals can cause many systemic manifestations, their oral manifestations are rare.

Macro – nutrients

Macro—nutrients consists of carbohydrates, proteins and lipids. These elements form the major portion of daily human diet. Awareness of their functions and effects on oral health is a very essential part of formulating a balanced diet (Table 2).

Table 2.

Sources and functions of macro–nutrients and their effects on oral health

Nutrients	Sources	Functions	Effects on Oral Health
Carbohydrates	Sugar, Pulses, Starchy vegetables	Main source of energy to cells, Overall growth and development	Increased susceptibility to dental caries
Proteins	Meat, Fish, Poultry, Soybean, Milk and milk products	Overall growth and development, Tissue repair and wound healing, Muscle growth and function, Immune function, Alternative source of energy	Decreased immune function, Impaired wound healing, Predisposition or susceptibility to oral infections
Lipids	Vegetable oils, Meat, Fish, Poultry, Milk and milk products, Nuts	Overall growth and development, Cell membrane maintenance, Vitamin absorption and storage, Alternative source of energy	Impaired tooth development, Periodontitis

Carbohydrates

Dental caries is perhaps the commonest oral health-related problem and through various long-term studies a well-established causal relationship has been established between carbohydrates and dental caries (Sreebny 1982). The dental caries process involves the degradation of dietary carbohydrates by oral bacterial flora to form organic acids, solubilizing the tooth surface. A significant drop in pH has been demonstrated in dental plaque of caries susceptible individuals on exposure to sugar compared to caries-free individuals (Stephan 1944). Overall there is a consensus that caries promoting effects of carbohydrates depend upon the amount, frequency, and form in which the sugar is consumed (Sreebny 1982). The term free sugar includes both naturally occurring as well as artificially added ones. World Health Organization (WHO) recommends free sugars to be less than 10% of total energy intake owing to the findings of higher incidence of caries found in populations where free sugar intake was greater than 10% (Moynihan and Kelly 2014). The frequency and stickiness of the sugar determine the duration of exposure of tooth surface to acidic pH which in turn determines the cariogenic potential of the carbohydrate (van Loveren 2019). However, the most important aspect remains the form of dietary carbohydrate intake. Sucrose, a disaccharide along with its constituent monosaccharides glucose and fructose, is more cariogenic because it is a specific substrate for glucosyl transferase, the enzyme in mutans streptococci responsible for the synthesis of extracellular polysaccharide glucan, which enters the glycolytic pathway more rapidly and results in a more pronounced drop in pH (Navia 1994; Bibby and Krobicka 1984). Lactose, a form of sugar found mostly in milk and dairy products, is less cariogenic, attributable to calcium in dairy products limiting enamel undersaturation during acidogenesis (Bradshaw and Lynch 2013). Many sugar alcohols like sorbitol, mannitol, maltitol, xylitol, etc. which are used as bulk sweeteners are also found to be less cariogenic. Many studies have shown that sugar alcohols like xylitol and sorbitol may even have a cariostatic or anti-cariogenic effect, probable postulations being a simple substitution for fermentable carbohydrates, in turn, reducing the acidogenic potential and inhibiting the growth of Streptococcus mutans (Bradshaw and Marsh 1994). Xylitol and other sugar alcohols are being widely tested as a substitute sweetener in milk chocolates and chewing gums, which augments their cariostatic activity by increasing the salivary flow (Janket et al. 2019; Rasouli 2021). A diet that is low in free sugars is good for both oral and overall health. It is recommended to limit consumption of high-glycemic, processed, fermentable carbohydrates (like sugar-sweetened foods and beverages) and consider the consumption of low-glycemic, unprocessed, complex carbohydrates (like apples, cranberries, tea, and high-fiber wholegrain carbohydrates) with modest amounts of legumes, lean meat, and plenty of fluids including milk and water (Santonocito et al. 2021; Moynihan et al. 2018).

Proteins

Chains of amino acids form proteins considered to be the basic building blocks of life. Proteins are essential for the growth, development, and repair of cells (Davis and Stegeman 1998). The human body can synthesize most of the amino acids, however, there are some called essential amino acids which dietary proteins must replenish. Both quantity and quality of protein in the diet need to be taken into consideration. Malnutrition and an unbalanced diet can lead to protein deficiency especially in developing or socioeconomically backward countries. While plant products lack one or more amino acids, animal products contain complete proteins, however, they are thought to increase insulin-like growth factor 1, which has been found to play an important role in carcinogenesis (Santonocito et al. 2021). Protein foods are usually not cariogenic. The main effects of protein deficiency on oral health are decreased immune function, impaired wound healing, and predisposition or susceptibility to oral infections (Romito 2003).

Lipids

Dietary lipids are an important source of energy, fat-soluble vitamins, and fatty acids. Fats form an important component of cells(phospholipids), nerve tissue, hormones and prostaglandins, and cholesterol. Solid fats and liquid oils form dietary lipids and are generally classified into triglycerides, phospholipids, and sterols. The majority of dietary lipids are triglycerides, which can be saturated and unsaturated (monounsaturated and polyunsaturated) fats (Axelsson et al. 2002). Polyunsaturated fats may be further classified as omega-3 fats or omega- 6 fats. Saturated and omega-6 polyunsaturated are generally considered unhealthy. However, fats should be a part of a balanced diet albeit with less saturated fats. Phospholipids being a structural component of cell membranes, enamel and dentin are involved in the mineralization of teeth and bone (Romito 2003). Studies have shown saturated fats and omega -6 fatty acids have an inflammatory effect on the periodontium and contrastingly, omega-3 fatty acids have demonstrated an anti-inflammatory effect (Santonocito et al. 2021).

Conclusion

A balanced diet is as important to oral health as it is to overall health. An excess or deficiency of a particular nutrient can have various manifestations in oral cavity. Awareness and adherence to the recommended intake of micro-and macro-nutrients can lead to developing and sustenance of a healthy oral cavity. These recommendations should also be taken up as a part of community health care initiatives. Government nutrition and food assistance programs must have an oral health component. They should have as a policy to increase consumer awareness regarding beneficial and deleterious effects of various contents on nutrition facts labels on packaged consumer foods.

Author’s contributions

CSN worked on the conception and preparation of the manuscript; SR worked in search and compilation of resources, preparation of tables and manuscript editing and revision.

Funding

This work did not receive any specific grant from funding agencies in the public, commercial, or not-for-profit sectors.

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Declarations

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The authors declare that they have no competing or conflict of interests.

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