The Role of Diet in Oral Disease Prevention

Oct. 14, 2013
Clinicians often overlook the effect of nutrition on the immune system and its role in periodontal disease progression.

Does diet really influence the course of periodontal disease?

Clinicians often overlook the effect of nutrition on the immune system and its role in periodontal disease progression. It is an important consideration, as we understand that diet plays a modifying role in the progression of periodontal disease. A periodontal lesion is essentially a wound, and sufficient host resources must be available for optimal healing. Previous studies have shown a clear association between risk of infection and nutrient status. Additionally, deficits in micronutrients are prevalent in older adults. These deficits have been linked to poor immune function.

For many years, we have known that foods high in fermentable carbohydrates contribute to caries formation. It is becoming clear that certain foods contribute to inflammation as well. Since periodontal diseases are chronic inflammatory diseases, it is reasonable to surmise that clinical outcomes can be influenced by a patient's diet.

The Forster Study

The Forster Study, published in the Journal of the American Geriatric Society last year, examined the effects of improved nutrition or micronutrient supplementation on infection in an older adult population. It is well established that poor nutrition increases susceptibility to infection, and infection has an adverse effect on nutritional status. It is also known that deficits in micronutrients are prevalent in older adults and are known to adversely affect immune function. In a randomized, placebo-controlled group of 217 adults between the ages of 65 and 85 over a six-month period, the conclusions were that improved dietary intake and micronutrient status reduced the impact of infections.

In this particular study, participants were randomized to one of three treatment arms (food, micronutrient, or placebo) and received the intervention for three months. Those participants in the food arm of the study were asked to consume at least five portions of fruit and vegetables per day, eat only whole-grain bread, consume fish at least twice a week, and consume nuts at least once a week. The researcher chose the specific foods provided in consultation with each participant, taking into account taste preferences and the intention of increasing intake of zinc, selenium, carotenoids, and vitamins C and E. A supermarket home delivery service delivered the food directly to participants.


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Participants randomized to the micronutrient or placebo groups were asked to consume one capsule per day. Each micronutrient capsule contained 1,500 μg of beta-carotene, two mg of vitamin E, 80 mg of vitamin C, two mg of zinc (zinc sulfate), and 25 μg of selenium (selenomethionine), with cellulose as the bulking agent. The content of the micronutrient capsule approximated the average incremental change in micronutrients that was anticipated through the dietary intervention. The placebo capsule contained cellulose and was identical in appearance to the micronutrient capsule. Participants randomized to the micronutrient and placebo groups were not given any explicit advice or recommendations regarding dietary change and were asked to remain on their normal diet.

The results of the study "provide evidence that improving the nutritional status of independently living older adults reduces the clinical impact of infections. The number of weeks in which symptoms of infection were reported was significantly lower in the food group than the placebo or micronutrient groups during the six-month period of the study. The number of weeks that illness affected life and the number of GP and hospital visits were significantly lower in the food and micronutrient groups than in the placebo group."

Dietary supplements in the treatment of periodontal disease

The effect of nutrition on the immune system and its role in periodontal disease has been reviewed. Neiva et al. (J Clin Periodontol, 2003) reviewed the literature on the use of specific nutrients to prevent or treat periodontal diseases. The investigators concluded that although the treatment of periodontal disease by nutritional supplementation has minimal side effects, the data on its efficacy are limited.

Several studies and case reports have evaluated the role of vitamin C in periodontitis. Nishida et al. (J Periodontol, July 2000) evaluated the effect of dietary intake of vitamin C and the presence of periodontal disease. Dietary intake of vitamin C showed a weak but statistically significant relationship to periodontal disease in current and former smokers as measured by clinical attachment. Interestingly, the greatest clinical effect on periodontal tissues was shown in smokers who took the lowest levels of vitamin C.

A low dietary intake of calcium is associated with severe periodontal attachment loss, and prevalence of periodontal disease decreases with high intake of dairy products. Hildebolt published a study in the Journal of Periodontology (September 2005) titled "Effects of Vitamin D and Calcium on Periodontitis." He found that deficiencies in vitamin D and calcium result in bone loss and increased inflammation. Another study published in September 2009 by Miley et al., titled "Cross-Sectional Study of Vitamin D and Calcium Supplementation Effects on Chronic Periodontitis," found that supplementation improved periodontal health. The consumption of at least 55 g of lactic-acid-containing foods per day significantly lowers the prevalence of periodontal disease when compared to no consumption. The benefit on periodontal health from the intake of lactic acid foods does not occur among smokers, likely because smoking is an important and perhaps overwhelming risk factor for periodontitis (Nishida et al., J Periodontol, 2000).

The Hisayama study (2008) found that oral lactobacilli suppress the growth of periodontal pathogens in vitro. The production of lactic acid through carbohydrate fermentation by oral lactobacilli generates a low pH, which might inhibit the growth of anaerobic bacteria. One of the important differences between lactic acid foods and other dairy products, such as milk and cheese, is the presence of lactobacilli. The plausible hypothesis that lactic acid foods may have a beneficial effect on periodontal disease might be based on the probiotic effect of lactobacilli in these foods. The regular consumption of lactic acid foods may constrain periodontal disease by controlling the overgrowth of periodontal pathogens in the oral cavity.

Probiotics are defined by the World Health Organization as "live microorganisms, which, when administered in adequate amounts, confer a health benefit on the host." Also known as "good bacteria," the probiotics most well-known are Lactobacillus and Bifidobacterium, each of which has several strains. Most common sources of probiotics include yogurts, select supplements, lozenges, juices, milks, cheeses, and soy products.

It has been suggested that probiotics can be beneficial in reducing dental caries, gingivitis, periodontitis, oral yeast infections, and halitosis through shifting the balance of good bacteria over bad bacteria. A number of studies support the claim that probiotics decrease the amount of S. mutans in the mouth, thereby reducing the likelihood of decay. However, there are some researchers who feel probiotics can actually increase the likelihood of dental caries due to the lactic acid, which can change the pH levels in the mouth. The subgingival application of beneficial bacteria S. sanguis, S. salivarius, and S. mitis (replacement therapy), has been shown to delay recolonization by periodontal pathogens, reduce inflammation, and improve bone density and bone levels in beagle dogs (Nackaerts et al., J Clin Periodontol 2008;35:1048-52).

Another interesting finding is that Omega-3 (v-3) polyunsaturated fatty acids (PUFA), including docosahexaenoic acid (DHA) and eicosapentaenoic acid (EPA), were shown to have therapeutic anti-inflammatory and protective actions in inflammatory diseases including periodontitis. In a study published in the Journal of Periodontology (Nov. 2010) titled "Adjunctive Treatment of Chronic Periodontitis with Daily Dietary Supplementation with Omega-3 Fatty Acids and Low-Dose Aspirin," 80 periodontal patients were followed for six months. Half of the participants received SRP and a placebo while the other half received SRP followed by dietary supplementation of fish oil (900 mg EPA + DHA) and 81 mg aspirin daily. Statistical analyses demonstrated a significant reduction in probing depths after three months and a significant attachment gain after six months in the PUFA group, compared to baseline and the control group. The results suggest that dietary supplementation with v-3 PUFAs and 81 mg aspirin may provide a sustainable, low-cost intervention to augment periodontal therapy.

The October 2011 issue of the Journal of Clinical Periodontology reported that "a diet supplemented with a combination of fruit and vegetable juice powder concentrates may help combat chronic periodontal disease when combined with conventional dental therapy." The results of a preliminary randomized controlled study conducted at the University of Birmingham showed that taking a daily dose of capsules containing concentrated phytonutrients improved clinical outcomes for patients with chronic periodontitis in the two months following nonsurgical periodontal therapy, with additional beneficial changes recorded at five and eight months after therapy. Volunteers age 30 and older with chronic periodontitis were randomly assigned to one of three groups: group A took fruit and vegetable powder concentrate capsules; group B took fruit, vegetable, and berry powder concentrate capsules; and group C took a placebo.

"The supplements, which are marketed commercially in more than 20 countries under the name Juice Plus+, were taken daily following nonsurgical scaling and cleaning of the root surfaces of the teeth." Sixty volunteers completed the two-month review, and 54 completed the eight-month review. Clinical outcomes improved significantly in all groups at two months as expected from the standard mechanical therapy. However, in the groups that took the supplements, the researchers found additional statistically significant improvements in gum pocketing at two months. Improvements in gum bleeding followed at five months and in lower dental plaque levels at eight months.

Excessive amounts of certain supplements can produce deleterious effects on the periodontium. There are several documented cases of excessive amounts of vitamin A causing a condition called hypervitaminosis A. This condition is characterized by bleeding gingiva, xerostomia, ulceration, and headache. Large doses of vitamin A are sometimes used in the treatment of acne.

Vegetarian and vegan diets

In a trend that seems to be growing, it is believed that about 10% of the American population follows a largely vegetarian-based diet. Despite the commonly held belief that these diets are more nutritious than regular diets, a vegetarian diet does not automatically translate into a healthy low-sugar, low-fat diet. Dr. Sam Shamoon, a spokesman for the Academy of General Dentistry says, "The Western world's idea of a vegetarian diet is cheese pizza with a lot of white flour and sugar in it. It's not that nutritious. If you eat potato chips and don't brush your teeth, that breaks down into sugar." Vitamin deficiencies can occur easily when the diet is deficient in nutrients, such as vitamins D, B2, B12, and calcium, which are plentiful in meat and dairy products. A lack of vitamins C and D and calcium can cause teeth to soften over time, which makes them more prone to tooth decay and periodontal disease.

Obesity and inflammation

It appears that we are overfed and undernourished. According to research conducted at the University of Maryland, Americans have shown a steady rise in obesity rates over the past 30 years. Many researchers feel that the typical American diet is largely to blame for the precipitous rise in obesity and the diseases associated with obesity, such as type 2 diabetes. Right now, it is estimated that 66% of adults are overweight or obese, 16% of children and adolescents are overweight, and by 2015, 75% of adults will be overweight and 41% will be obese.

Inflammation is the primary cause of cardiovascular disease and periodontal disease. We know that human fat cells secrete 12 different inflammatory cytokines, including interleukin-6 and tumor necrosis factor, which affect the metabolism throughout the body and contribute to the development of low-grade systemic inflammation (Shuldiner, N Engl J Med, 2001 and Genco, Scientific American, 2006).

Numerous studies have shown that obesity has been associated with an increased risk for susceptibility and severity of periodontal disease (Al-Zahrani, J Periodontol, Aug 2005). Tomofuji et al. (J Dent Res., 2005) reported that a diet rich in high-density cholesterol was associated with the migration of the junctional epithelium and increased bone resorption in rats.

Unfortunately, restricting fat intake and using cholesterol-lowering drugs does not decrease the incidence of inflammation in artery walls. Without inflammation, cholesterol would not accumulate in the walls of blood vessels, causing heart attacks and strokes, according to Dr. Dwight Lundell, MD in The Cure for Heart Disease (March 2012). "Cholesterol-lowering drugs DO NOT WORK. Inflammation is the real culprit. Inflammation is the result of injury, infection, or irritation. Further, chronic inflammation is just as harmful as acute inflammation is beneficial."

Heart disease researchers have suggested that diets low in fat and high in polyunsaturated fats and carbohydrates create chronic inflammation. Examples of highly processed carbohydrates include products with high concentrations of sugar and flour and omega-6 vegetable oils, including sunflower, soybean, and corn.

Dietary carbohydrates and dental-systemic disease

In the 1960s, two researchers, Dr. T. L. Cleave and Dr. John Yudkin, postulated that excessive dietary fermentable carbohydrate intake led – in the absence of dental interventions such as fluorides – first to dental diseases and then to systemic diseases. Under this hypothesis, dental and systemic diseases shared – as a common cause – a diet of excess fermentable carbohydrates. Today, there is renewed interest in this decades-old hypothesis, namely that dental diseases – caries and periodontal diseases – are early warning signals for the development of diabetes, obesity, and coronary heart disease.

The question we should consider is this: How could a diet that is bad for dental health be good for systemic health, i.e. a diet high in fermentable carbohydrates? Dental caries do not develop in the absence of fermentable carbohydrates. Further, six clinical trials suggest that moderate reduction in carbohydrate intake reduces gingivitis scores on average by one third. In 1965, Cheraskin et al. published a study demonstrating that the addition of two 50-gram sucrose drinks a day increased pocket depth in four days. Eliminating refined carbohydrates reduced gingival bleeding in weeks, independent of oral hygiene.

Periodontal diseases and caries have been called diseases of civilization or Western lifestyle diseases. Evidently, changes in the human diet have been accompanied by an increased incidence of a myriad of chronic and noncommunicable systemic diseases (CNCD) such as obesity, type 2 diabetes, cardiovascular diseases, and some cancers. Likewise, modern Western lifestyle and foods (i.e., softened/highly processed, fatty, salty, sweetened, etc.) are major causes of dental caries and periodontal disease. RDH

Dianne Glasscoe Watterson, RDH, BS, MBA, is a professional speaker, writer, and consultant to dental practices across the United States. She is CEO of Professional Dental Management, based in Frederick, Md. To contact Glasscoe Watterson for speaking or consulting, call (301) 874-5240 or e-mail [email protected]. Visit her Web site at www.professionaldentalmgmt.com.

Helping our patients understand

Research is ongoing in the field of nutritional supplements and their effects on the progression of periodontal diseases and caries. However, we must be realistic and understand that merely taking vitamin and mineral supplements or adding some vitamins to processed foods will not prevent the diseases associated with eating a diet containing a low percentage of calories from whole natural foods. Scientists cannot formulate nutrients that have not yet been discovered into pills.

In treating the periodontal patient successfully, how many of us stop to consider the role of the patient's diet in the healing process? Having a patient keep a weekly food diary was a task we completed in hygiene or dental school, but few clinicians incorporate serious nutritional counseling into the treatment protocol. Could the reason be lack of time, or is it that we are not walking the walk ourselves? How can we be passionate about high-quality nutrition if we don't practice it ourselves?

Are we just treating symptoms when we treat caries or periodontal disease? "Eliminating symptoms is like responding to a car's oil light by clipping the wires rather than addressing the underlying causes." (Nesse, 2007).

More and more, we are coming to the realization that the foods we ingest are an important part of the human inflammatory process. Al-Zahrani et al. (2005) published in the Journal of Periodontology as part of an NHANES study with over 12,000 subjects that individuals who maintained normal weight, engaged in the recommended level of exercise, and had a high-quality diet were 40% less likely to have periodontitis compared to individuals who maintained none of these healthy behaviors.

With so many food choices available today, it is important for us to help our patients understand which foods comprise a healthy diet. We should be teaching our patients to avoid processed foods and sugar as much as possible. A nutritious diet includes lots of green, leafy vegetables, legumes and beans, raw fruits, nuts, and lean meats such as oily fish. Since periodontal disease is an inflammatory disease, foods that are known inflammation fighters are important for periodontal patients to include in their diets. Those foods include oily fish, such as salmon, tuna, and sardines, high in omega-3 and vitamin D; brightly colored fruit and vegetables such as red onions, tomatoes, broccoli, red cabbage, garlic, red bell pepper, red grapes, cherries, plums, oranges; all kinds of raw fruit, as fruit consumption has been shown in numerous studies to offer our strongest protection against certain cancers, especially oral and esophageal, lung, prostate, pancreatic, and colorectal cancer; extra virgin olive oil; freshly brewed tea, which contains catechins; dark chocolate; and the spices ginger, turmeric, and curry, which contain curcumin.

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About the Author

Dianne Glasscoe Watterson, MBA, RDH

DIANNE GLASSCOE WATTERSON, MBA, RDH, is a consultant, speaker, and author. She helps good practices become better through practical analysis and teleconsulting. Visit her website at wattersonspeaks.com. For consulting or speaking inquiries, contact Watterson at [email protected] or call (336) 472-3515.

Updated June 30, 2020