J Periodontol • April 2015
Letters to the Editor To the Editor: Re: Coffee Consumption and Periodontal Disease in Males. Ng N, Kaye EK, Garcia RI. (J Periodontol 2014;85:1042-1049.) We read with great interest the article by Ng, Kaye, and Garcia. The authors are commended for publishing, for what appears to be the first time, data regarding effects of coffee consumption on periodontal disease in humans, but there are a few comments we would like to make. 1. The authors have highlighted the antioxidant effect of caffeine as playing a protective role in periodontitis. However, there are other dietary sources of antioxidants that could have played a similar role in reducing periodontal disease but were not mentioned in the article. 2. In the Cornell Medical Index, the participants responded to the question, ‘‘Do you drink more than six cups of coffee/tea a day?’’, and the authors reported that participants who consumed more than six cups of coffee/tea per day had fewer teeth with alveolar bone loss (ABL) ‡40%. Our query is regarding the lack of segregation of tea versus coffee consumption in the questionnaire since the caffeine content of tea varies greatly according to different types of tea, and there are other components in tea like catechins that have been proven to have beneficial effects on periodontal health.1-3 3. Using the food frequency questionnaire, the authors have classified the participants into two groups, one of which is more than one cup per day. This group can include any number of cups above one, so a proper quantity that can be considered high caffeine intake is not understood, considering that previous animal studies have shown high doses of caffeine to increase ABL.4,5 4. In the questionnaire, the participants were questioned about ‘‘any periodontal treatment in the past year (yes or no),’’ but no further elaboration regarding the type of periodontal therapy was provided. Our concern is whether these periodontal therapies could have contributed to reduction of ABL. Saumiya Gopal, Rama Dental College and Research Center, Kanpur, India, and Abhijeet Shete, Tatyasaheb Kore Dental College and Research Center, Kolhapur, India.
The authors report no conflicts of interest related to this letter.
REFERENCES 1. RateTea.com. Caffeine content of tea. Available at: http://ratetea.com/topic/caffeine-content-of-tea/21/. Accessed September 26, 2014. 2. Mayo Clinic. Healthy lifestyle: Nutrition and healthy eating. Caffeine content for coffee, tea, soda and more. Available at: http://www.mayoclinic.org/healthy-living/ nutrition-and-healthy-eating/in-depth/caffeine/art20049372. Accessed September 27, 2014. 3. Kushiyama M, Shimazaki Y, Murakami M, Yamashita Y. Relationship between intake of green tea and periodontal disease. J Periodontol 2009;80:372-377. 4. Bezerra JP, da Silva LR, de Alvarenga Lemos VA, Duarte PM, Bastos MF. Administration of high doses of caffeine increases alveolar bone loss in ligature-induced periodontitis in rats. J Periodontol 2008;79:2356-2360. 5. Bezerra JP, de Siqueira A, Pires AG, Marques MR, Duarte PM, Bastos MF. Effects of estrogen deficiency and/or caffeine intake on alveolar bone loss, density, and healing: A study in rats. J Periodontol 2013;84:839-849. Submitted September 27, 2014; accepted for publication September 27, 2014. doi: 10.1902/jop.2015.140550
Authors’ Response: We appreciate the thoughtful comments in the letter. The authors correctly note that there are many other antioxidants in the diet in addition to those found in coffee. We highlighted the caffeine literature mainly because of our primary research question regarding coffee consumption and because the nutrient database for the food frequency questionnaire (FFQ) at that time had values only for caffeine and not for the chlorogenic acids and other phenols that make up a large part of the antioxidant, antibacterial, and anti-inflammatory compounds in coffee. We agree that our findings suggest that a valuable next step would be to add information on these other antioxidants to our database and reevaluate our hypothesis. The letter notes that in the Cornell Medical Index (CMI), the participants responded to the question ‘‘Do you drink more than six cups of coffee/tea a day?’’ and that participants who consumed more than six cups of coffee/tea per day had fewer teeth with alveolar bone loss (ABL) ‡40%. We used the FFQ data to verify the analyses using the CMI. The FFQ data did separate out tea, caffeinated, and decaffeinated coffee. The only one of those beverages that we found to be associated with ABL was caffeinated coffee. We also used the FFQ data to classify participants into two groups, one of which is more than one cup per day. It is important to note that the findings in our study cannot be extrapolated to coffee intakes 489
Letters to the Editor
beyond those we observed in our cohort. As Bezerra et al.1 stated, the daily caffeine dose used in the animal studies was equivalent to 16 cups of coffee. In contrast, the maximum daily caffeine intake in our cohort was 1,000 mg, or the equivalent of 10 cups of coffee. We also performed and reported on a regression analysis in which caffeine was treated as a continuous variable and found that the number of teeth with ABL also decreased with increasing caffeine intake. In the Dental Longitudinal Study questionnaire, the participants were asked about ‘‘any periodontal treatment in the past year (yes or no),’’ but no further elaboration regarding the type of periodontal therapy was given. Periodontal treatment, as assessed by this single question, was included a priori in the regression models along with several factors (such as smoking) that may directly affect an individual’s outcome of alveolar bone loss. The effect of periodontal treatment was small and not statistically significant at P
Letters to the Editor To the Editor: Re: Coffee Consumption and Periodontal Disease in Males. Ng N, Kaye EK, Garcia RI. (J Periodontol 2014;85:1042-1049.) We read with great interest the article by Ng, Kaye, and Garcia. The authors are commended for publishing, for what appears to be the first time, data regarding effects of coffee consumption on periodontal disease in humans, but there are a few comments we would like to make. 1. The authors have highlighted the antioxidant effect of caffeine as playing a protective role in periodontitis. However, there are other dietary sources of antioxidants that could have played a similar role in reducing periodontal disease but were not mentioned in the article. 2. In the Cornell Medical Index, the participants responded to the question, ‘‘Do you drink more than six cups of coffee/tea a day?’’, and the authors reported that participants who consumed more than six cups of coffee/tea per day had fewer teeth with alveolar bone loss (ABL) ‡40%. Our query is regarding the lack of segregation of tea versus coffee consumption in the questionnaire since the caffeine content of tea varies greatly according to different types of tea, and there are other components in tea like catechins that have been proven to have beneficial effects on periodontal health.1-3 3. Using the food frequency questionnaire, the authors have classified the participants into two groups, one of which is more than one cup per day. This group can include any number of cups above one, so a proper quantity that can be considered high caffeine intake is not understood, considering that previous animal studies have shown high doses of caffeine to increase ABL.4,5 4. In the questionnaire, the participants were questioned about ‘‘any periodontal treatment in the past year (yes or no),’’ but no further elaboration regarding the type of periodontal therapy was provided. Our concern is whether these periodontal therapies could have contributed to reduction of ABL. Saumiya Gopal, Rama Dental College and Research Center, Kanpur, India, and Abhijeet Shete, Tatyasaheb Kore Dental College and Research Center, Kolhapur, India.
The authors report no conflicts of interest related to this letter.
REFERENCES 1. RateTea.com. Caffeine content of tea. Available at: http://ratetea.com/topic/caffeine-content-of-tea/21/. Accessed September 26, 2014. 2. Mayo Clinic. Healthy lifestyle: Nutrition and healthy eating. Caffeine content for coffee, tea, soda and more. Available at: http://www.mayoclinic.org/healthy-living/ nutrition-and-healthy-eating/in-depth/caffeine/art20049372. Accessed September 27, 2014. 3. Kushiyama M, Shimazaki Y, Murakami M, Yamashita Y. Relationship between intake of green tea and periodontal disease. J Periodontol 2009;80:372-377. 4. Bezerra JP, da Silva LR, de Alvarenga Lemos VA, Duarte PM, Bastos MF. Administration of high doses of caffeine increases alveolar bone loss in ligature-induced periodontitis in rats. J Periodontol 2008;79:2356-2360. 5. Bezerra JP, de Siqueira A, Pires AG, Marques MR, Duarte PM, Bastos MF. Effects of estrogen deficiency and/or caffeine intake on alveolar bone loss, density, and healing: A study in rats. J Periodontol 2013;84:839-849. Submitted September 27, 2014; accepted for publication September 27, 2014. doi: 10.1902/jop.2015.140550
Authors’ Response: We appreciate the thoughtful comments in the letter. The authors correctly note that there are many other antioxidants in the diet in addition to those found in coffee. We highlighted the caffeine literature mainly because of our primary research question regarding coffee consumption and because the nutrient database for the food frequency questionnaire (FFQ) at that time had values only for caffeine and not for the chlorogenic acids and other phenols that make up a large part of the antioxidant, antibacterial, and anti-inflammatory compounds in coffee. We agree that our findings suggest that a valuable next step would be to add information on these other antioxidants to our database and reevaluate our hypothesis. The letter notes that in the Cornell Medical Index (CMI), the participants responded to the question ‘‘Do you drink more than six cups of coffee/tea a day?’’ and that participants who consumed more than six cups of coffee/tea per day had fewer teeth with alveolar bone loss (ABL) ‡40%. We used the FFQ data to verify the analyses using the CMI. The FFQ data did separate out tea, caffeinated, and decaffeinated coffee. The only one of those beverages that we found to be associated with ABL was caffeinated coffee. We also used the FFQ data to classify participants into two groups, one of which is more than one cup per day. It is important to note that the findings in our study cannot be extrapolated to coffee intakes 489
Letters to the Editor
beyond those we observed in our cohort. As Bezerra et al.1 stated, the daily caffeine dose used in the animal studies was equivalent to 16 cups of coffee. In contrast, the maximum daily caffeine intake in our cohort was 1,000 mg, or the equivalent of 10 cups of coffee. We also performed and reported on a regression analysis in which caffeine was treated as a continuous variable and found that the number of teeth with ABL also decreased with increasing caffeine intake. In the Dental Longitudinal Study questionnaire, the participants were asked about ‘‘any periodontal treatment in the past year (yes or no),’’ but no further elaboration regarding the type of periodontal therapy was given. Periodontal treatment, as assessed by this single question, was included a priori in the regression models along with several factors (such as smoking) that may directly affect an individual’s outcome of alveolar bone loss. The effect of periodontal treatment was small and not statistically significant at P
