11: Vitamins Required for Oral Soft Tissues and Salivary Glands

Vitamins Required for Oral Soft Tissues and Salivary Glands

Physiology of Soft Tissues

The oral cavity can reflect systemic disease before other signs (noticeable to the clinician) and symptoms (perceived by the patient) become evident; the condition in the oral cavity may also cause systemic problems by affecting the patient’s nutrient intake. The oral cavity is the site of a wide variety of systemic disease manifestations for several reasons: (a) it has a rapid cellular turnover rate, (b) it is under constant assault by microorganisms, and (c) it is a trauma-intense environment.

The systemic circulation provides nutrients and removes metabolic waste products from underlying structures and the salivary glands via the blood supply. Figure 11-1 shows healthy gingiva; changes in color, size, shape, texture, and functional integrity of the oral tissues often reflect systemic nutritional disorders. Signs and symptoms in soft oral tissues can be caused by deficiencies of many of the B-complex vitamins, vitamins C and E, iron, and protein (Box 11-1). Nutritional deficiencies result in similar oral signs and symptoms, such as pain, erythema, atrophy of tissues, and infection. Pyogenic (producing pus) and fungating (skin lesions with ulcerations, necrosis, and foul smell) microorganisms cause local infections in cracked epithelial surfaces. Approximately 90% of saliva is produced and secreted by three paired sets of major salivary glands: the parotid, submandibular, and sublingual glands (Fig. 11-2). Additionally, the lips and inner lining of the cheeks are equipped with hundreds of minor salivary glands.

Saliva keeps surfaces of the oral cavity healthy and lubricated and is necessary to maintain functional integrity of taste buds. Solid substances first must be dissolved in saliva to be tasted. Healthy adults produce approximately 1 to 1.5 L/day of saliva. Sympathetic autonomic nerves stimulate the body in times of stress and crisis; sympathetic impulses influence salivary composition. Parasympathetic autonomic nerves balance or slow down impulses from sympathetic nerves; parasympathetic stimulation increases the amount of saliva secreted.

Compared with plasma, saliva is hypotonic, with its main constituent being water. Hypotonic solutions have a lower solute concentration than plasma. Saliva contains more than 20 proteins and glycoproteins, and many electrolytes, including sodium, potassium, calcium, chloride, bicarbonate, inorganic phosphate, magnesium, sulfate, iodide, and fluoride. Saliva functions as a buffer to maintain the oral pH. Buffering substances increase their acid or alkali content to change the pH of the solution. The pH of unstimulated saliva is approximately 6.1, but this can rise to 7.8 at high flow rates. Antimicrobial properties of saliva provide protection and remove toxins, such as tobacco smoke.

The oral cavity is lined with nonkeratinized mucosa except for the hard palate, dorsum of the tongue, and gingiva surrounding the teeth, which are covered with a keratinized epithelium (a protein, main component of epidermis and horny tissues). The oral cavity may contain antigenic (capable of inducing an immune response with specific antibodies) substances; the oral mucosa separates a potentially adverse environment from underlying connective tissue.

Mucosal cells have a very rapid turnover rate, resulting in complete turnover in 3 to 5 days. Rapid generation of new cells in the oral epithelia provides replacement tissue for trauma resulting from friction of the teeth and mastication. Additionally, hundreds of cells in the filiform papillae and fungiform papillae are in constant transition, from their anabolism until their catabolism (Fig. 11-3). Filiform papillae are smooth, threadlike structures on the dorsum surface of the tongue, whereas fungiform papillae are red, mushroom-shaped structures scattered throughout the filiform papillae.

Taste buds are located on the foliate papillae (vertical grooves located on the lateral borders of the tongue), circumvallate lingual papillae (large, mushroom-shaped distinct structures forming a V) on the dorsal surface, and the fungiform papillae of the tongue. A loss of fungiform and foliate papillae leads to loss of taste buds and changes in taste acuity.

Many filiform papillae cover the anterior two-thirds of the tongue. If the filiform papillae become denuded or atrophied, the tongue appears red and pebbled, giving it a strawberry-like appearance. Fungiform papillae are bright red because of a rich vascular supply. Keratinized cells normally cover the fungiform papillae on the tongue surface. Chronic severe nutrient deficiencies result in loss of fungiform papillae and a smooth red tongue.

Thiamin (Vitamin B1)

Physiological Roles

Thiamin functions as a coenzyme in metabolism of energy nutrients via the TCA cycle (or Krebs or citric acid cycle) to produce energy. This role makes it crucial for normal functioning of the brain, nerves, muscles, and heart. However, the main effects of thiamin deficiency are disturbances of carbohydrate metabolism, which is impossible without thiamin. Thiamin is a component necessary for the synthesis of niacin, and it also helps regulate appetite. It is a constituent of enzymes that degrade sucrose to organic acids that can ultimately dissolve tooth enamel.

Requirements

Thiamin is involved in using carbohydrates as kilocalories; the requirement is based on total caloric need. The recommended dietary allowance (RDA) for men (≥14 years old) is 1.2 mg/day and for women (≥19 years old) is 1.1 mg/day (Table 11-1). Participation in rigorous physical activity uses more energy, so more thiamin is required. Also, requirements are increased by pregnancy and lactation, hemodialysis or peritoneal dialysis, fever, hyperthyroidism, cardiac conditions, alcoholism, and the use of loop diuretics. No known adverse effects are evident from excessive thiamin intake, including supplements. Although a tolerable upper intake level (UL) is not established for thiamin, care should be taken when consumption routinely exceeds the RDA.

Table 11-1

Institute of Medicine recommendations for thiamin

Life Stage EAR (mg/day)* RDA (mg/day) AI (mg/day)
Male Female Male Female
0-6 months         0.2
7-12 months         0.3
1-3 years 0.4 0.4 0.5 0.5  
4-8 years 0.5 0.5 0.6 0.6  
9-13 years 0.7 0.7 0.9 0.9  
14-18 years 1 1 1.2 1  
≥19 years 1 0.9 1.2 1.1  
Pregnancy
14-50 years   1.2   1.4  
Lactation
14-50 years   1.2   1.4  

image

*EAR (estimated average requirement)—the intake that meets the estimated nutrient needs of half of the individuals in a group.

RDA (recommended dietary allowance)—the intake that meets the nutrient needs of almost all (97% to 98%) individuals in a group.

AI (adequate intake)—the observed average or experimentally set intake by a defined population or subgroup that seems to sustain a defined nutritional status, such as growth rate, normal circulating nutrient values, or other functional indicators of health. An AI is used if insufficient scientific evidence is available to derive an EAR. For healthy human milk–fed infants, the AI is the mean intake. The AI is not equivalent to a RDA.

Data from Institute of Medicine (IOM), Food and Nutrition Board: Dietary reference intakes for thiamin, riboflavin, niacin, vitamin B6, folate, vitamin B12, pantothenic acid, biotin, and choline, Washington, DC, 1998, National Academy Press.

Sources

Thiamin is widely distributed in foods, and intake of a variety of foods, including enriched grains or whole grains, can ensure adequate amounts (Table 11-2). Approximately 40% of thiamin intake is provided by enriched breads, cereals, and pasta. (Because of enrichment, enriched breads may contain almost twice as much thiamin as whole grains). In the meat group, pork is an exceptionally good source. Other good sources include nuts and legumes. Following the guidelines for MyPlate and eating a variety of foods ensures adequate intake.

Table 11-2

Thiamin content of selected foods

Food Portion Thiamin (mg)
Total, whole grain 1 cup 2.0
Wheaties 1 cup 1.0
Trail mix, tropical 1 cup 0.63
Lean pork chop, broiled 3 oz 0.44
Green peas, cooked 1 cup 0.41
Bagel, wheat image-4 inches 0.40
White rice, enriched, cooked 1 cup 0.26
Bread, white, enriched 1 slice 0.15
Bread, whole-wheat 1 slice 0.13
Sweet potato, baked 1 cup 0.12
Peanuts, dry roasted 1 oz 0.12

image

Data from U.S. Department of Agriculture, Agricultural Research Service. USDA national nutrient database for standard reference, release 26, 2013. Nutrient Data Laboratory Home Page. Accessed August 30, 2013. Available at: www.ars.usda.gov/nutrientdata

Hypo States

Thiamin is required for metabolism of carbohydrates, proteins, and fats; insufficient intake adversely affects most organ systems. Primary dietary deficiency usually occurs in developing countries where polished rice is the staple diet. In developed countries, thiamin deficiency is secondary to alcoholism, ingestion of raw fish containing microbial thiaminase (an enzyme that inactivates thiamin), chronic febrile states, and total parenteral nutrition (TPN). Cooking deactivates thiaminase.

Thiamin is called the “morale vitamin” because short-term deficiency causes patients to become depressed, irritable, anorexic, fatigued, and unable to concentrate. The brain and central nervous system, almost entirely dependent on glucose for energy, are seriously impaired when thiamin is unavailable.

Severe thiamin deficiency results in beriberi, which causes extensive damage to the nervous and cardiovascular systems. Beriberi means “I cannot”; patients with this severe thiamin deficiency cannot move easily. The classic chronic form of beriberi manifests with impairment of sensory and motor function without involvement of the central nervous system. Other symptoms include muscular wasting (dry beriberi), edema (wet beriberi), deep muscle pain in the calves, peripheral paralysis, tachycardia (rapid heartbeat), and an enlarged heart.

Whether or not a thiamin deficiency is evident in oral tissues is controversial. Some clinicians have associated a flabby, red, and edematous tongue with thiamin deficiency (Fig. 11-4). The fungiform papillae become enlarged and hyperemic (engorged with blood).

Wernicke-Korsakoff syndrome is another thiamin deficiency disease, typically associated with alcoholism, which is characterized by mental confusion, nystagmus (involuntary rapid movement of the eyeball), and ataxia (a gait disorder characterized by uncoordinated muscle movements). These symptoms occur most frequently in malnourished alcoholics. Alcohol intake increases thiamin requirement, yet total nutrient intake is usually poor in alcoholics. Early diagnosis is essential to initiate thiamin therapy early in the course of the disease to prevent permanent damage and death.

image Dental Considerations

• A careful medical, social, and dietary history, including a clinical assessment of the oral cavity, alcohol consumption, and activity level, help identify early stages of thiamin deficiency.

• Risk of alcohol abuse or dependence is based on how much and how often an individual drinks. Moderation is considered 4 to 14 drinks per week for men and 3 to 11 drinks per week for women; five or more drinks per occasion is considered excessive for any adult.

• Vitamin deficiencies seldom occur in isolation. If a deficiency is suspected, symptoms of other vitamin B deficiencies also may be present.

• Because thiamin is essential for carbohydrate metabolism, a thiamin deficiency is closely linked to aberrations of brain function. For patients who are confused or have altered thought processes, assess nutrient intake.

• Carbohydrate loading or a very-high-carbohydrate diet and high physical activity slightly increase the thiamin requirement. (Generally, increased food intake results in increased thiamin consumption.)

• Thiamin deficiency has been reported in patients after gastrectomy and bariatric surgery (gastric bypass) related to decreased absorption.

• Although immediate clinical response to thiamin therapy is often dramatic, ultimate recovery may be incomplete, and relapses may occur, especially if precipitating factors persist.

• Massive amounts (1000 times greater than the RDA) of thiamin suppress the respiratory system and cause death.

Riboflavin (Vitamin B2)

Physiological Roles

Riboflavin functions as a coenzyme in metabolism of carbohydrate, protein, and fat to release cellular energy. Closely related to the metabolism of protein, all conditions requiring increases in protein (e.g., growth spurts or burns) lead to additional riboflavin requirements. Riboflavin is also essential for healthy eyes and skin, and maintenance of mucous membranes. Along with thiamin, riboflavin is necessary for synthesis of niacin.

Requirements

As shown in Table 11-3, the Institute of Medicine (IOM) recommends an intake of 1.3 mg/day for men (14 years old and older) and 1.1 mg/day for women (19 years old and older). This level is influenced by individual energy requirements. Additionally, when nitrogen balance is positive, more riboflavin is retained. No UL has been established.

Table 11-3

Institute of Medicine recommendations for riboflavin

Life Stage EAR (mg/day)* RDA (mg/day) AI (mg/day)
Male Female Male Female
0-6 months         0.3
7-12 months         0.4
1-3 years 0.4 0.4 0.5 0.5  
4-8 years 0.5 0.5 0.6 0.6  
9-13 years 0.8 0.8 0.9 0.9  
14-18 years 1.1 0.9 1.3 1  
≥19 years 1.1 0.9 1.3 1.1  
Pregnancy
14-50 years   1.2   1.4  
Lactation
14-50 years   1.3   1.6  

image

*EAR (estimated average requirement)—the intake that meets the estimated nutrient needs of half of the individuals in a group.

RDA (recommended dietary allowance)—the intake that meets the nutrient needs of almost all (97% to 98%) individuals in a group.

AI (adequate intake)—the observed average or experimentally set intake by a defined population or subgroup that seems to sustain a defined nutritional status, such as growth rate, normal circulating nutrient values, or other functional indicators of health. An AI is used if insufficient scientific evidence is available to derive an EAR. For healthy human milk–fed infants, the AI is the mean intake. The AI is not equivalent to a RDA.

Data from Institute of Medicine (IOM), Food and Nutrition Board: Dietary reference intakes for thiamin, riboflavin, niacin, vitamin B6, folate, vitamin B12, pantothenic acid, biotin, and choline, Washington, DC, 1998, National Academy Press.

Sources

Although milk and milk products are excellent sources of riboflavin, approximately 30% of the dietary intake is furnished by foods in the grain group (Table 11-4). Meat, poultry, and fish also provide about one-fourth of the dietary requirement.

Table 11-4

Riboflavin content of selected foods

Food Portion Riboflavin (mg)
Beef liver, braised 3 oz 3.08
Total, whole grain 1 cup 2.28
Wheaties 1 cup 1.12
Cheese, American 1 oz 0.67
Custard, egg 1 cup 0.67
Yogurt, low-fat, plain 8 oz 0.49
Milk, skim 1 cup 0.45
Cottage cheese, low-fat 1 cup 0.45
Spinach, cooked 1 cup 0.43
Pork loin, lean only, baked 3 oz 0.28
Egg, hard boiled 1 0.26
Cornbread 1 slice 0.19
Chicken breast, meat only, roasted 1 0.16
Cheese, cheddar 1 oz 0.11

image

Data from U.S. Department of Agriculture, Agricultural Research Service. USDA national nutrient database for standard reference, release 26, 2013. Nutrient Data Laboratory Home Page. Accessed August 30, 2013: www.ars.usda.gov/nutrientdata

Hypo States

The body carefully guards its limited riboflavin stores. Even in severe deficiency, one-third of the normal amount is present in the liver, kidney, and heart. Primary riboflavin deficiency is uncommon, but is encountered in patients with multiple nutrient deficiencies as a result of poor nutrient absorption or use. Because riboflavin is essential in vitamin B6 and niacin functions, riboflavin deficiency leads to symptoms related to secondary deficiency of these nutrients.

Symptoms associated with riboflavin deficiency, or ariboflavinosis, include angular cheilitis (Fig. 11-5), glossitis (Fig. 11-6), dermatitis, and anemia. With consistently inadequate intake, these symptoms may be observed within 8 weeks. Along with angular cheilosis, the lips may become extremely red and smooth. Fungiform papillae become swollen and slightly flattened and mushroom-shaped during early stages of riboflavin deficiency; the tongue has a pebbly or granular appearance. Severe chronic deficiencies lead to progressive papillary atrophy and patchy, irregular denudation of the tongue. The tongue may become purplish red or magenta in color because of vascular proliferation and decreased circulation. In more advanced cases, the entire tongue may become atrophic and smooth (Fig. 11-6). These symptoms, especially glossitis and dermatitis, may be secondary to vitamin B6 deficiency.

Niacin (Vitamin B3)

Physiological Roles

The term niacin is loosely used to refer to two compounds, nicotinic acid and nicotinamide. Both compounds are used by the body. Niacin is crucial as a coenzyme in energy (adenosine triphosphate) production. It functions with riboflavin in glucose production and metabolism and is involved in lipid and protein metabolism. Niacin also functions in enzymes involved in microbial degradation of sucrose to produce organic acids.

Requirements

The body obtains niacin not only directly from food, but also indirectly from conversion of an amino acid, tryptophan, and from synthesis by intestinal microorganisms. RDAs are given in terms of niacin equivalents, which include dietary sources of niacin plus its precursor, tryptophan. Approximately 1 mg of niacin may be formed from 60 mg of dietary tryptophan. Niacin requirements are related to caloric intake. The RDA niacin equivalents for adults are 14 to 16 mg daily (Table 11-5). The UL for adults is 35 mg daily. There is no known adverse effect related to naturally-occurring niacin in foods.

Table 11-5

Institute of Medicine recommendations for niacin

Life Stage EAR (mg/day)* RDA (mg/day) AI (mg/day)§image UL (mg/day)
Male Female Male Female
0-6 months         2 ND
7-12 months         4 ND
1-3 years 5 5 6 6   10
4-8 years 6 6 8 8   15
9-13 years 9 9 12 12   20
14-18 years 12 11 16 14   30
≥19 years 12 11 16 14   35
Pregnancy
14-18 years   14   18   30
≥19 years   14   18   35
Lactation
14-18 years   13   17   30
≥19 years   13   17   35

image

*EAR (estimated average requirement)—the intake that meets the estimated nutrient needs of half of the individuals in a group.

Niacin equivalents.

RDA (recommended dietary allowance)—the intake that meets the nutrient needs of almost all (97% to 98%) individuals in a group.

§AI (adequate intake)—the observed average or experimentally set intake by a defined population or subgroup that seems to sustain a defined nutritional status, such as growth rate, normal circulating nutrient values, or other functional indicators of health. An AI is used if insufficient scientific evidence is available to derive an EAR. For healthy human milk–fed infants, the AI is the mean intake. The AI is not equivalent to a RDA.

imagePreformed niacin.

ND—not determinable because of lack of data of adverse effects in this age group and concern with regard to lack of ability to handle excess amounts. Source of intake should be from food and formula to prevent high levels of intake.

Data from Institute of Medicine (IOM), Food and Nutrition Board: Dietary reference intakes for thiamin, riboflavin, niacin, vitamin B6, folate, vitamin B12, pantothenic acid, biotin, and choline, Washington, DC, 1998, National Academy Press.

Sources

Niacin is widely distributed in plant and animal foods. Good sources include meats, cereals, legumes, seeds, and nuts (Table 11-6). Approximately 65% of the niacin in the U.S. diet is obtained from meat and milk. Tryptophan is found mainly in milk, eggs, and meats. The RDA for niacin equivalents is easily met by consuming foods high in niacin and foods containing tryptophan.

Table 11-6

Niacin content of selected foods

Food Portion Niacin (mg)
Beef liver, braised 3 oz 15.77
Wheaties 1 cup 13.32
Chicken breast, skinless, cooked 3 oz 12.84
Salmon, cooked 3 oz 8.24
Halibut, broiled 3 oz 6.72
Tuna, white, canned in water 3 oz 4.93
Turkey, whole, cooked 3 oz 4.80
Peanuts, dry roasted 1 oz 3.83
Potato, white, baked 1 med 2.64
Mushrooms, raw 1 cup 2.53
Rice, enriched white, cooked 1 cup 2.33
Milk, skim 1 cup 0.23

image

Data from U.S. Department of Agriculture, Agricultural Research Service. USDA national nutrient database for standard reference, release 26, 2013. Nutrient Data Laboratory Home Page. Accessed August 30, 2013: www.ars.usda.gov/nutrientdata

Hyper States and Hypo States

Supplemental doses of nicotinic acid (3 to 6 g/day) are effective in reducing low-density lipoprotein (LDL) cholesterol and triglycerides, while increasing high-density lipoprotein (HDL) cholesterol. (Nicotinamide does not function in this role.) Despite positive changes in serum lipid levels, a large study funded by National Institutes of Health using a combination of niacin supplements and statin did not reduce risk of CHD (heart attacks and strokes), causing the study to be terminated early.1,2

The use of 50 mg of niacin taken daily can function as a vasodilator, producing flushing of the skin, itching, tachycardia, nausea and vomiting, and severe liver damage. Extended-release niacin is associated with few gastrointestinal symptoms without increasing liver damage. Because the body is able to store some niacin, larger doses associated with supplements may lead to serious problems, including abnormal liver function and gout.

Niacin deficiency is usually associated with a maize (corn) diet because corn products contain all the essential amino acids except tryptophan. This diet increases the body’s requirements for tryptophan and niacin. A deficiency is also seen in alcoholics but is unlikely in individuals who consume adequate protein. Niacin deficiency results in degeneration of the skin, gastrointestinal tract, and nervous system, a condition known as pellagra. Symptoms of pellagra have been referred to as “the 4 Ds”—dermatitis, diarrhea, depression or dementia, and death. The term pellagra is derived from the Latin word for animal hide; the skin may become rough and resemble goose flesh. The most striking and characteristic sign of pellagra is a reddish skin rash, especially on the face, hands, or feet, which is always bilaterally symmetrical (i.e., appears on both sides of the body at the same time) (Fig. 11-7A). It flares up when skin is exposed to strong sunlight. Neurological symptoms include depression, apathy, headache, fatigue, and loss of memory. If untreated, it may lead to death.

Jan 1, 2015 | Posted by in Dental Hygiene | Comments Off on 11: Vitamins Required for Oral Soft Tissues and Salivary Glands
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