Diets and Dental Hygiene

Many patients enter the dental practice thinking they’ve done all they can to protect their oral health. They brush, they floss, and they regularly make their 6-month appointments. They think if they tick these boxes, they have taken all the steps toward ensuring their oral health.

However, these patients are missing a critical piece of the puzzle: diet. While patients understand that getting their fruits and vegetables is important for overall health, there’s little comprehension of how a poor diet can affect oral health.

“People don’t understand that their oral health is related to their diet,” says Ellie Campbell, DO, MS, FAAOSH, secretary of the American Academy for Oral & Systemic Health (AAOSH). “They think, ‘Oh, it may affect my body, my weight, my energy level, or my sleep,’ but they don’t think about oral health. I think people have made systemic connections to their diet, but I don’t think most people have a clue that it affects your mouth as well.”

The Oral-Systemic Connection

Another part of the problem stems from the lack of understanding about oral-systemic health in general. While poor oral health has been linked to a wide range of systemic conditions (including stroke, diabetes, and cardiovascular disease), many people don’t understand how issues in the mouth can contribute to systemic problems.

“Diet is an essential piece of the overall puzzle,” says Sam Shamardi, DMD, diplomate of the American Board of Periodontology and Implant Surgery. “So much of our population suffers from diabetes and overall insulin resistance, all of which are linked to overall wound healing and periodontal inflammation and breakdown. We are what we eat, is the saying; hence what we eat will impact our health.”

According to the American Dental Association, 2 oral health factors can contribute to these systemic conditions.¹ The first is inflammation in the oral cavity. Chronic inflammation (such as that caused by periodontal disease) can increase inflammatory markers in the bloodstream. This can affect the body’s immune response and stress the body’s disease burden. Secondly, pathogenic bacteria in the oral cavity can enter the bloodstream and travel throughout the body, affecting other areas.

“The mouth and rest of the body are completely connected,” says Mike Milligan, DMD, a founding member and board member of AAOSH. “One affects the other. It has been said that the mouth is the gateway to the body and that good health begins in the mouth. Oral pathogenic bacteria and their toxic byproducts and effects enter the bloodstream and travel throughout our cardiovascular system and tissues with varied deleterious effects.”

The pH Problem

Inflammation is triggered by several factors, many of which stem from dietary decisions. It is well known that consuming sucrose-rich food such as sugars and carbohydrates plays a large role. Sugars attract bacteria that result in biofilms and bacterial plaque.

“The biggest culprits of inflammation are sugar and flour—and all the products made from them—as well as the consumption of too many omega-6 vegetable oils like soybean, corn, and sunflower found in many processed foods,” Dr Milligan says.

The bacterial components bolstered by sugar can trigger inflammatory responses that result in periodontal disease. As bacteria within the plaque metabolize the sugar, they release acid—a primary contributor to caries and decay.²

Because acid can demineralize and dissolve enamel, bacterial acid production is a big concern. Demineralization occurs when pH levels drop below 5.5 for a significant period. When more fermentable carbohydrates are available to plaque bacteria, the pH rises. When carbohydrates are not available, the pH decreases. These fluctuations affect the demineralization and remineralization processes. As such, the frequency of sugar intake, duration of exposure, and pH level of consumables can greatly affect demineralization.

“There’s no such thing as junk food; it’s either junk or it’s food,” Dr Campbell says. “We need to talk to our patients about nutrition and inform them. If you see dental plaque, let them know it may mean they have too much acid in their diet. What are they drinking? Inform them about the effects of high pH beverages and how [they] can weaken enamel.”

For example, water has a neutral pH of 7.0 with zero sugar content. Beverages with pH levels below 7.0 and with higher sugar content begin to cause demineralization. In comparison, Pepsi has a 2.49 pH, with 9.8 tsp of sugar per 12-oz can. Mountain Dew has a pH of 3.22 and contains 11 tsp of sugar. Even sugar-free drinks can cause issues due to their high pH: While Diet Pepsi doesn’t contain sugar, it has a pH of 3.05.For reference, battery acid has a pH of 1.0—just 1.49 lower than a can of Pepsi.⁴

Sports drinks are also problematic because of their high pH and sugar content, and prevalence of use across demographics. A bottle of Gatorade has a pH of 2.95 and 3.3 tsp of sugar.⁴ In a 2016 survey of adolescents, 87% of respondents indicated that they drank sports drinks, with over 50% reporting drinking them at least 2 or more times per week.⁵ Other studies have shown an increased risk of dental caries in elite athletes who regularly consume sports drinks.^6,7 Because athletes train regularly and often take repeated small sips of the beverages, they increase their exposure time to pH and sugar.

Because increased exposure time results in increased periods of demineralization, sticky foods with high pH and sugar content pose a significant risk. This can be compounded by high levels of citric acid in fruit-flavored gummies, chews, or candies. For example, Skittles and gummy bears both have a pH of 2.5. Other high-exposure foods include hard candies that must be sucked on for extended periods of time.⁸

Foods With Benefits

With so much talk of foods that are bad for oral health, it’s also important to emphasize to patients the foods that can bolster oral health and well-being (and ones that can mitigate the effects of inevitable dietary bad habits). When it comes to mitigating the effects of diet on oral health, there are several things that patients can do.

“Putting a higher priority on minimizing processed foods, decreasing sugar intake, and trying to create more balance in what and how much we eat all make a major impact,” says Dr Shamardi. “It doesn’t take radical changes to create radical results.”

This balance comes from making good nutritional choices that benefit both oral and systemic health.

Dairy

Thanks to high concentrations of phosphates and calcium, dairy products can help strengthen tooth enamel. In addition, milk and other dairy products are noncariogenic and can counter high pH levels by temporarily reducing them. Research in Denmark discovered that adults with high milk intake had a reduced risk of periodontitis.⁹ Additionally, another study found that consuming milk lowered saliva pH after 5 min before it rose again at the 15-min mark.¹⁰

Whole grains and fiber

Increased whole-grain and fiber intake has also been associated with a reduced risk of periodontal disease.¹¹ Replacing refined grains (which are often high in sugar) with whole grains can have a positive effect on oral health. A study of over 34,000 male health professionals in the United States found that participants in the highest quintile of whole-grain consumption were 23 percent less likely to develop periodontitis.¹² Diets high in whole grains have also been associated with a reduced risk of type 2 diabetes.¹³

In addition to whole grains, high-fiber foods like crunchy fruits and vegetables have an inverse association with periodontal disease. In addition to being high in fiber, foods that require more chewing (such as apples, carrots, broccoli, and celery) stimulate saliva production. Saliva is one of the most important factors in reducing dental erosion, as it neutralizes dietary acids and promotes remineralization.¹⁴

Greens

Leafy greens such as lettuce, cabbage, spinach, and collard greens contain vitamins and nitrates that can bolster oral health. Nitrates stimulate healthy oral genera and help protect against acids by increasing lactate consumption and ammonia production.¹⁵ Studies have also found that a high intake of green and leafy vegetables rich in vitamin C, folate, and carotenoids offers anticarcinogenic properties and can decrease oral cancer risks.¹⁶

Water

Saliva production is reduced when dehydration occurs, so staying hydrated is critical to oral health. Adults should drink at least 64 oz of water daily to stay properly hydrated. Water also helps flush out the mouth, removing debris, reducing bacteria, and supporting a healthy oral microbiome. Thanks to its neutral pH, it does not introduce acids into the oral cavity but instead helps neutralize the pH of saliva.

The Importance of Education

By making smart nutritional choices, patients can prevent periodontal issues, enamel erosion, and caries. However, since nutrition and oral health are intrinsically linked, one is impossible without the other.

“Tooth loss, decay, periodontal disease, and thermal sensitivity can all affect chewing, food choices, and getting the proper nutrition that is essential for total body wellness,” Dr Milligan says. “Conversely, proper nutrition can significantly affect dental health, including pocket depth and bleeding sites. So, the mouth affects nutrition, and nutrition affects the mouth.”

Dental professionals have a unique opportunity to educate patients on the contribution of nutrition to oral health and oral-systemic well-being. Through education, patients can learn to make beneficial nutritional decisions that increase their oral health.

“Many dental patients don’t have a primary care provider, or a person who is their trusted health provider—except for the hygienist,” Dr Campbell says. “I think this is a role the hygienist can pick up when they have the patient as a captive audience. Clinicians should ask patients what their water intake is, or how many fruits and vegetables they are getting, and explain how these things keep teeth strong and promote oral health. It’s a minute of offhand conversation that can start their wheels turning.”

Introducing this to patients early and consistently can pay off, Dr Campbell says. If patients hear this message at every dental cleaning, twice a year, it starts making an impact.

“As health professionals—whether you’re a dentist, an eye doctor, a dermatologist, or a primary care doctor—we all need to be spending more time on those fundamentals of wellness,” Dr Campbell says. “Then hopefully we can keep that prescription pad in our back pocket for the times when these therapeutic lifestyle changes don't work.”

References

1. Oral-systemic health. American Dental Association. Updated September 11, 2023. Accessed April 3, 2024. https://www.ada.org/resources/ada-library/oral-health-topics/oral-systemic-health/

2. Sugars and tooth decay. Action on Sugar. Accessed April 2, 2024. https://www.actiononsugar.org/sugar-and-health/sugars-and-tooth-decay/

3. Joshipura K, Dietrich T. Nutrition and oral health: a two-way relationship. In: Bales CW, Ritchie CS, eds. Handbook of Clinical Nutrition and Aging. 2nd ed. Humana Press; 2009:247-262

4. Minnesota Dental Association: acidity (pH) and sugar content of beverages. Oralsystemiclink.net. May 17, 2017. Accessed April 1, 2024. https://oralsystemiclink.net/health-care-providers/profile/minnesota-dental-association-acidity-ph-and-sugar-content-of-beverages-1

5. Broughton D, Fairchild RM, Morgan, MZ. A survey of sports drinks consumption among adolescents. Br Dent J. 2016;220(12):639-643. doi:10.1038/sj.bdj.2016.449

6. Frese C, Frese F, Kuhlmann S, et al. Effect of endurance training on dental erosion, caries, and saliva. Scand J Med Sci Sports. 2015;25(3):e319-e326. doi:10.1111/sms.12266

7. Bryant S, McLaughlin K, Morgaine K, Drummond B. Elite athletes and oral health. Int J Sports Med. 2011;32(9):720-724. doi:10.1055/s-0031-1277192

8. Ritchie CS, Bales CW. Handbook of Clinical Nutrition and Aging. 1st ed. Humana Press; 2004.

9. Shimazaki Y, Shirota T, Uchida K, et al. Intake of dairy products and periodontal disease: the Hisayama study. J Periodontol. 2008;79(1):131-137. doi:10.1902/jop.2008.070202

10. Sharma A, Sharma D, Singh S, Sharma A, Sharma R, Sharma M. Milk and its products: effect on salivary pH. Int Healthcare Res J. 2018;2(6):140-145. doi:10.26440/IHRJ/02_06/198

11. Nielsen SJ, Trak-Fellermeier MA, Joshipura K, Dye BA. Dietary fiber intake is inversely associated with periodontal disease among US adults. J Nutr. 2016;146(12):2530-2536. doi:10.3945/jn.116.237065

12. Merchant AT, Pitiphat W, Franz M, Joshipura KJ. Whole-grain and fiber intakes and periodontitis risk in men. Am J Clin Nutr. 2006;83(6):1395-1400. doi:10.1093/ajcn/83.6.1395

13. Fung TT, Hu FB, Pereira MA, et al. Whole-grain intake and the risk of type 2 diabetes: a prospective study in men. Am J Clin Nutr. 2002;76(3):535-540. doi:10.1093/ajcn/76.3.535

14. Buzalaf MA, Hannas AR, Kato MT. Saliva and dental erosion. J Appl Oral Sci. 2012;20(5):493-502. doi:10.1590/s1678-77572012000500001

15. Rosier BT, Buetas E, Moya-Gonzalvez EM, Artacho A, Mira A. Nitrate as a potential prebiotic for the oral microbiome. Sci Rep. 2020;10(1):12895. doi:10.1038/s41598-020-69931-x

16. Hirayama T. A large scale cohort study on cancer risks by diet: with special reference to the risk reducing effects of green-yellow vegetable consumption. Princess Takamatsu Symp. 1985;16:41-53.