Poor nutrition can hinder proper
development of the oral hard and soft tissues as well as contribute to tooth
decay and periodontal conditions in the established oral environment. The relationship between diet and dental
caries has been known for some time.
But certain changes and conditions that manifest in the oral soft
tissues can also be related to deficiencies in the diet.
That sugar intake is
directly related to the development of tooth decay has been well
established. Simple sugars, including
monosaccharides and disaccharides, are referred to as “fermentable
carbohydrates”. Fermentable carbohydrates
can be broken down in the mouth by salivary amylase and are easily metabolized
by oral bacteria, especially Streptococcus
mutans and Lactobacillus. When this metabolism of simple sugars
occurs, acid is produced in the mouth, causing the pH of the plaque to drop to
5.5 or lower. A pH of 5.5 is the
critical level at which demineralization of the enamel begins to occur. Fermentable carbohydrates can thus be defined
as those foods that cause the pH of the oral environment to drop to 5.5,
beginning the process of enamel demineralization. Complex carbohydrates, or polysaccharides,
are not metabolized by oral bacteria and therefore do not contribute to tooth
decay as the simple sugars do.
have shown that there are other factors besides simply the presence of
fermentable carbohydrates that contribute to caries formation. Some of these factors are: whether or not the
sugar is eaten with a meal, the place of the carbohydrate within the meal, the
frequency of ingestion, the retentiveness of the carbohydrate, and the effects
A fermentable carbohydrate that is
eaten as part of a meal is less damaging to the teeth than a carbohydrate that
is eaten between meals as a snack. The
other foods that are part of the meal tend to offset the effects of the
fermentable carbohydrate. This is
especially true if the carbohydrate is followed during the meal by a fat or
protein food. Proteins and fats are
considered to be anticariogenic because they do not lower the pH of the oral
environment. A fat or protein food that
is eaten after a fermentable carbohydrate will help to neutralize the acidic
effects of the carbohydrate. Dairy
foods like cheese, milk, and yogurt, especially, are cariostatic and good
choices for ending a meal.
When a fermentable carbohydrate is
consumed over a period of time (for instance, sipping on a sugared drink for an
hour or two), the oral environment is continuously exposed to the acid produced
by the bacterial metabolism of the carbohydrate. This continuous exposure does not allow the
saliva to do its job of neutralizing and buffering. Therefore, consuming a fermentable
carbohydrate over time is much more damaging to the teeth than eating it within
a few minutes. Another factor to
consider is the retentiveness of the fermentable carbohydrate. “Sticky” foods, of course, are more damaging
because they tend to adhere to the teeth and are not cleared from the mouth
easily by the saliva.
Saliva is an important factor
affecting the rate of caries formation.
One of the actions of saliva is to clear the mouth of food debris;
therefore it’s necessary to have a sufficient amount of saliva to wash away debris
successfully. Studies show that a
reduced flow or absence of saliva is associated with an increased presence of
caries. Xerostomia, which is the
reduction or absence of saliva, can be related to certain systemic conditions.
Xerostomia, in varying degrees, also occurs at
higher rates in the elderly population.
This fact helps explain why root caries are often a problem for elderly
people. The recession that can occur in
the older population, along with reduced salivary flow, combine to cause caries
on the exposed root surfaces. Root
caries can be particularly destructive and fast-moving due to the lack of
protective enamel on the root surface and the thinner structure of the root
In addition to physically clearing
the oral environment, saliva contains buffering and antimicrobial
properties. The pH of saliva is normally
in the neutral range of about 6.5 to 7.5.
This neutral pH means the saliva works to buffer the acidic pH caused by
fermentable carbohydrates and bring the pH of the oral environment back into a
more neutral state. As for saliva’s
antimicrobial properties, the main antibody in saliva is Immunoglobulin A. Immunoglobulin A has been shown to act
against S mutans and other oral
bacteria associated with the presence of caries.
Saliva also has been shown to have
remineralization properties. Ions in
the saliva, including fluoride and phosphate, promote remineralization of the
enamel, thereby helping to reverse the demineralization caused by fermentable
Sugar alcohols, also called polyols
and non-nutritive sweeteners, are often used in foods to replace sucrose,
glucose, and other simple sugars.
These non-nutritive sweeteners are called sugar alcohols because their
molecular structures resemble both that of sugar and of an alcohol. Mannitol, sorbitol, and xylitol are widely
used sugar alcohols. They are considered
noncariogenic because they are fermented in the mouth much more slowly than
simple sugars. They also are lower in
calories than sugars. Sugar alcohols
are not easily digested or absorbed by the body, so they do not cause the rise
in blood sugar that simple sugars do.
Sugar alcohols occur naturally in
fruit and other plant foods, but they are also commercially produced and used
in other foods. The use of sugar
alcohols has a long history, but their use in foods has increased in recent
years with new techniques available.
Sugar alcohols are a good sugar substitute for people with diabetes The
anticariogenic effects of xylitol were discovered in the 1970’s with studies
done in Finland.
Most of the sugar alcohols have only 35--75%
of the sweetness of sugar. Xylitol,
however, has the same sweetness level as sugar.
Studies show that xylitol, like the other sugar alcohols, is
anticariogenic, increases salivary flow (thus aiding in clearance of the oral
environment), and acts as a buffer.
With these characteristics, and its sweetness equaling that of sucrose,
xylitol is a popular choice as a sweetener in chewing gums, candies, and mints.
Xylitol is also available as a sugar substitute which can be used as table
sugar is used---for baking, sweetening coffee or tea, etc. It is suggested that for the most
effectiveness at preventing caries, six to ten grams of xylitol per day should
Very recent studies suggest that xylitol may
assist with wound healing and be effective against ear and nose infections and
even osteoporosis. Research is ongoing
in these fields, but the oral benefits of xylitol are unquestioned.
Non-nutritive sweeteners (sugar
alcohols) and artificial sweeteners (such as saccharin and aspartame) are not
the same. Artificial sweeteners contain
zero calories or carbohydrates, while non-nutritive sweeteners contain an
average of 2.6 calories per gram and do contain some carbohydrates. Neither will contribute to caries as sugar
does. The most common drawback to
consuming sugar alcohols is that because they are not completely digested and
absorbed by the body, they can cause bloating and diarrhea when consumed in
Water and Fluoride
A popular practice related to
nutrition that is of some concern is the increased consumption of bottled water
instead of tap water. Many communities
fluoridate their tap water, which has helped to reduce decay rates over the
past 30 to 40 years. Bottled water
often contains no fluoride, so there is some concern that the widespread
substitution of bottled water for tap water may reverse this downward trend in
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The role of diet as a cause of periodontal disease is not as
clear as the relationship between fermentable carbohydrates in the diet and
dental caries. But research has
established a definite relationship between nutrition and periodontal
disease. Individuals who have poor
nutritional habits tend to have more periodontal disease and other oral
diseases than those people who maintain a healthy diet. A healthy diet sufficient in vitamins and
minerals seems to help protect the body’s tissues, including oral tissues.
between poor nutrition and oral disease can be a vicious cycle. Poor nutrition in general, and especially
deficiencies of certain vitamins, can lead to oral conditions (like gingivitis)
that produce pain that makes it difficult to eat. This difficulty in eating exacerbates the
poor nutrition, and so the cycle repeats itself. This cycle is especially applicable when
systemic diseases, such as cancer or HIV/AIDS are present.
deficiencies often produce symptoms in the oral environment, so the dental
professional is in a unique position to recognize these symptoms and help the
patient. Both dental and dietetic
professionals are realizing the benefit to patients of working together to
improve patients’ nutritional health.
In cases of extremely poor nutrition or after periodontal surgery,
especially when poor nutrition has played a part in the periodontal disease
process, a nutritionist or dietician may be called upon to counsel the dental
patient in proper nutrition to promote healing. This teamwork approach is becoming more
common in the health professions as understanding of the relationship between
nutrition and healing increases.
relationship between vitamin C deficiency and scurvy is one example of how the
lack of good nutrition can contribute to oral diseases of soft tissues. Scurvy can be described as very severe
gingivitis, with extremely painful and bleeding gingiva. In the days of sailing vessels that were at
sea for months at a time, scurvy was common among the sailors who became
deficient in vitamin C due to the lack of fresh fruits and vegetables. Eventually this link between lack of fruit
(especially citrus) and scurvy became known, and in 1867, the Merchant Shipping
Act required the Royal Navy to supply limes and lemons on all their sailing
ships. Later research established that
it was vitamin C in the citrus fruit that prevented scurvy.
Although scurvy itself is rare
today, especially in developed countries, a deficiency of vitamin C can still
be associated with increased gingival bleeding. Vitamin C is necessary for the production
and healing of collagen, so it is important in the healing of wounds or after
surgery. Other nutrients involved in the
healing process include vitamin A, zinc, and protein.
Food sources of vitamin C include
most fruits and vegetables, especially citrus fruits, cantaloupe, kiwi fruit,
berries, broccoli, red and green peppers, spinach, and other fruits and
vegetables. Some cereals are fortified
with vitamin C. The best sources are
raw or uncooked fruits and vegetables; cooking reduces the vitamin C content in
foods. Vitamin A food sources include
dairy products, liver, fish, and fortified cereals. Protein can be obtained in meats, milk,
fish, eggs, beans, legumes, and some grains.
The B Vitamins
Along with vitamins C and A, the B
vitamins are very important in maintaining the health of the oral soft
tissues. Vitamin B is actually a
complex of vitamins including thiamin, riboflavin, niacin, folic acid (folate),
pantothenic acid, biotin, and vitamins B6 and B12. Deficiencies in the B vitamins can result in
oral soft tissue changes, including glossitis, cheilosis, burning or furrowed
tongue, aphthous ulcers, and cracked lips, among other changes. Cheilosis and glossitis are two symptoms of
riboflavin (vitamin B2)deficiency. A mild deficiency of niacin (vitamin B3)
can result in cankersores (aphthous ulcers); a severe of niacin causes
pellagra. Symptoms of pellagra include
dermatitis, edema, and skin and oral lesions as well as psychological
symptoms. Pellagra is often described by
the “four D’s”: diarrhea, dermatitis, dementia, and death. The
classic oral symptom of pellagra is a swollen, bright red (“beefy red”)
A severe deficiency of thiamine
(vitamin B1) causes beriberi, which also has oral symptoms similar
to those described for the other B vitamins.
Deficiencies of most of the B vitamins are rare; deficiency of vitamin B12
is the most common deficiency of the B vitamins. Vitamin B12 deficiency is most
often seen in vegans and some vegetarians because the most reliable sources of
B12 are meat and dairy products.
It’s recommended that vegans, particularly, consider taking vitamin B12
Folic acid (folate is the term for
the naturally-occurring form in the body) is another B vitamin. Folate deficiency is rare in the United States,
but it is very important that pregnant women get enough folic acid especially
early in the pregnancy to prevent neural tube defects in the fetus. Some recent studies suggest that good levels
of folic acid can reduce the risks for certain cancers, but the evidence is
conflicting and research is ongoing.
Deficiencies of the B vitamins,
particularly thiamine, niacin, and folic acid, are also related to
alcoholism. This is partly due to the
poor diet of many alcoholics and also to the fact that alcohol abuse impairs the
absorption capabilities of the gastrointestinal tract. The brain damage that occurs with long-term
alcohol abuse is often due to severe deficiencies of thiamine and niacin.
Food sources for the B vitamins
include whole grains, potatoes, beans, turkey, tuna, liver. Unprocessed foods are a good source of
vitamin B; processing of flour and other foods tends to reduce the levels of
vitamin B. Vitamin B12 is
obtained mostly from meat and dairy products.
Vitamin D and Calcium
Vitamin D, in addition to having
cardiovascular and immunity effects, contributes to bone health. Vitamin D and calcium work together. Studies show that 99% of the calcium in the
body is in the bones and teeth; only 1% of calcium is located in the
blood. A deficiency of vitamin D can
lead to poor absorption of calcium, resulting in inadequate bone levels or loss
of bone. This can lead to osteoporosis,
and it can also affect periodontal bone health.
There is some evidence that magnesium and vitamin K also contribute to
Vitamin D is naturally present in
very few foods. Fatty fish, such as
salmon, tuna, and mackerel, are good sources.
In the United States,
most milk is fortified with vitamin D.
Exposure to sunlight is a main source of vitamin D for most people;
generally, it’s recommended to have 5 to 30 minutes of exposure to the sun
twice a week. People who don’t get
sufficient sun exposure need to be certain that they get enough vitamin D
through the diet. Dark green leafy
vegetables and nuts are good sources of magnesium. Green leafy vegetables also have vitamin K,
but the main source of vitamin K is synthesis by bacteria in the large
Other vitamins and minerals that
affect oral health are vitamin E, which contributes to healing of the oral
tissues, and zinc, a lack of which can alter the senses of taste and
smell. A deficiency of iron can lead to
anemia, symptoms of which often are seen first in the oral soft tissues as
unusual paleness of the gingiva.
Vitamin E can be obtained from eating
nuts, seeds, vegetable oils, fortified cereals, and green leafy
vegetables. Zinc is present in a variety
of foods; oysters contain more zinc than any other food. Zinc is also present in beans, nuts, dairy
products, meat, poultry, and whole grains.
Sources of iron include dried
beans and fruits, egg yolks, iron-fortified cereals, meat, poultry, salmon,
tuna, and whole grains.
Recent research has suggested that
certain omega-3 and omega-6 fatty acids can act against periodontal
disease. These polyunsaturated fatty
acids in the diet act as antioxidants to reduce the effects of
inflammation. Omega-3 fatty acids seem
to have the most effect; one study demonstrated an inverse relationship between
periodontal disease and omega-3 fatty acids.
These fatty acids benefit the entire body as well as the oral
Foods high in omega-3 fatty acids
include whole grains, fresh fruits and vegetables, fish, olive oil, and
garlic. Omega-6 fatty acids can be
obtained mostly from vegetable oils.
Evidence is mounting that consuming
enough fruits and vegetables can help prevent oral cancer. Some studies demonstrate an inverse
relationship between fruit and vegetable consumption and the occurrence of oral
cancer. Fruit, especially, seems to have
the most effect on oral cancer rates.
There is some evidence that consumption of whole grains may also be
protective against oral cancer, but the evidence is not as strong for whole
grains as it is for fruits and vegetables.
Most experts agree that the best
and most effective way to consume sufficient macro- and micronutrients is
through the diet rather than through supplements. Some studies do suggest that in certain
situations (for instance, after periodontal surgery), supplementation may be
warranted to aid healing, but ordinarily it’s recommended that most people
should aim to get their nutrients from a well-balanced diet.
Systemic conditions, including
nutritional deficiencies, often show symptoms first in the oral tissues. For this reason, it is imperative that dental
professionals be able to recognize changes that occur in the oral mucosa, and
be prepared to address those changes, either with educational measures and
proper dental treatment or by referring the patient to the appropriate health