A study of the relationship between diet and acne: a Chinese medicine approach
Introduction
Acne is a common skin problem in young people and can lead to certain psychological disorders or mental disorders. Although the influence of dietary factors in causing or exacerbating acne is widespread among acne patients and even physicians, there has been no clinical study to prove this link. There is a contradiction between the results of clinical studies and the testimony of individual patients and careful examination by clinicians. Recent studies have reported interesting results indicating the possibility that diet-induced hyperinsulinemia and intake of whole and skim milk can be accompanied by increased acne, but the results of this study have been reviewed and reviewed by other authors raising questions.
The inference of homogeneity in acne patients may be confusing and is similar to chronic hepatitis B virus infection. Previously, patients with hepatitis B virus were restricted to “carriers” of the virus, but this labeling does not infer that all carriers are homogeneous, making the question of what this hypothesis implies about the best way to deal with hepatitis B virus carriers not simply answered. Once a patient is categorized by test as, for example, viral DNA loading, presence of hepatitis B e (HBe) antigen nuclear Hbe antibodies, transaminase levels and co-infection with hepatitis C or D or human immunodeficiency virus, it then becomes simpler to answer the question of what to do about it. Similarly, this may be the time to use to classify different acne patients.
Traditional Chinese medicine (TCM), with its emphasis on individualized diagnosis and treatment, meaning that the same factor (e.g., diet) acting on individuals with different body types can produce different responses (e.g., the appearance of acne), may be a useful tool for this classification. Chinese medicine has been used for over 2000 years and is being recognized by Western societies on the increase, with a profound understanding of the relationship between diet and acne. In the Yellow Emperor’s Classic of Internal Medicine, the first and most important classical Chinese medicine text, we are warned that “gluttony can cause ulcers”, while in the Authentic Book of Surgery it is stated that “fumes from food residues in the stomach that reach the lungs can become acne”.
In this study, we used the best principle of yin and yang in Chinese medicine to classify the subjects as yin or yang individuals. The hypothesis of this study was that (1) all subjects’ diets were not related to acne and (2) the identified foods were related to acne in yin or yang individual subjects.
Methods
Subjects
This is a recent cross-sectional study from the University of Hong Kong, China. All new students were invited to participate in this study if they were local residents and could read Chinese. The study was approved by the University Clinical Research Ethics Committee and written informed consent was obtained from all subjects participating in the study. 27 of the 416 invited students declined to participate, resulting in a response rate of 93.5% (389/416). Subsequently, 67 of the cases that also came for analysis had incomplete data, so the completion rate was 77.4% (322/416).
Clinical diagnosis of acne in terms of clinical severity
The International Acne Grading System (GAGS) is a system for clinically grading acne severity. Clinical acne severity is rated for all subjects by a GAGS-trained and certified rater. To minimize bias due to some subjects not having adequate exposure, the chest and upper back of all subjects were examined; we did not examine these locations (patients were <5% more likely to have acne on the chest and upper back alone with a complete lack of facial exposure). Therefore, we adjusted the GAGS score and the classification criteria for assigning clinical severity of acne according to proportions (Annex 1). Subjects were divided into 2 groups: (1) the clinical acne group (n=82, 25.2%) with moderate or severe acne, and (2) the reference group (n=240, 74.5%) with no or only mild acne (we considered mild acne as a normal physiological phenomenon during puberty).
Yin and yang prevalence
At the core of TCM is the theory of yin and yang, which allows for individual differences in symptoms (a more difficult TCM diagnosis), so we attempted to evaluate diet-acne correlations using the concept of yin and yang. We supplemented this with four TCM-trained practitioners in Hong Kong. They collected clinical information from the subjects using the four diagnostic techniques of TCM: looking, smelling, asking, and cutting. They then analyzed the symptoms and signs to determine the yin and yang of the subjects based on the “eight syndromes” of yin and yang, appearance and interior, cold and heat, and deficiency and actuality. According to the TCM theory, yin flourishes on the inside, including reduced activity, obscure color, cold, pale white tongue, and slow, deep and weak pulse. Yang prevalence on the outside included hyperactivity, bright color, heat, red tongue, and superficial, fast, and strong pulse. Based on their ratings, four practitioners evaluated each subject’s yin and yang scores according to a scale of -10 to +10, with 0 representing the balance value. The mean of each subject’s yin and yang scores was calculated and their relative difference (yin score minus yang rating) represented the predominance of one over the other, respectively. If different > 0, subjects were assigned to the yin predominance group and if different < 0, they were assigned to the yang predominance group.
The diagnosis and evaluation of TCM is required to be holistic and qualitative. We previously thought of using more objective methods such as quantifying each of the eight syllabuses to derive “balance” values, but we consulted with TCM experts who considered this approach to be reductionist, and therefore we based our study on this holistic approach.
Dietary evaluation and other data collection
The identified Youth Risk Behavior Questionnaire (Hong Kong applicable version) was used to study the dietary habits of the subjects. Eleven classifications of food consumed during the first 7 days of the study were evaluated. These classifications were (1) snacks; (2) chocolate or candy; (3) dry food; (4) street food; (5) desserts, ice cream, cakes, fruit tarts; (6) soft drinks; (7) sweet iced drinks; (8) fruit juices; (9) fresh fruits; (10) vegetables; (11) milk or soy milk, and the frequency was categorized as 0 times/week, 1-2 times/week, 4-6 times/week, 1 time/day, 1 time/day 2 times/day, 3 times/day and ≥4 times/day.
We also collected other data that may affect severe acne, such as gender, age, body mass index, medication history (including oral contraceptives) in the 6 months prior to this study, smoking and alcohol habits, sleep quantity and quality, psychological or emotional problems, and cognitive ability (as rated by the Cognitive Ability Scale). We did not collect a family history of acne because evidence that severe acne is genetic is still lacking and this self-reported information may be inaccurate because there is no standardized diagnosis and recall bias.
Statistical analysis
Baseline characteristics were calculated as mean, median, or percentage for all subjects and for each group of subjects. All subjects and each group of subjects were tested for the independent relationship between food and the presence of clinical acne using the Multivariate logit model. The regression models obtained contained all dietary variables (we did not perform any selection manipulation in the models), and therefore the models were applied to all measured dietary variables. p<0.05 (paired) was considered statistically significant, and residual values and confidence intervals were calculated. All analyses were performed with SAS software (version
8; SAS Institute, Chicago, IL, USA) to complete.
Results
Details of all subjects are presented in Table 1. There were 155 subjects (48.1%) in the yin-sheng group and 167 (51.9%) in the yang-sheng group (25.5%). Characteristics that may affect severe acne (gender, body mass index, smoking and alcohol consumption habits) were distributed in both groups.
Relationship between diet and clinical severity of acne
All subjects were analyzed as a homogeneous group and no food was significantly associated with the presence of acne (Table 2). However, in the yin-sheng group, we found a lower association between higher consumption of street foods and possibly having clinical acne (Table 2). In the yang-sheng group, higher consumption of desserts and fresh fruit juices was associated with a higher likelihood of developing clinical acne, while higher consumption of milk or soy products was associated with a lower likelihood of developing clinical acne (Table 2).
Discussion
Using the TCM individualized concept, we found an association between acne and identified foods, contrary to the results of previous studies. This may be an explanation for the relationship between diet and acne in clinical practice without controlled evidence and the lack of relevant evidence for this association in clinical studies.
In TCM, the balance of yin and yang is the root cause of disease onset and progression. One of the main theories of yin and yang is that “the opposite is true”, when yang meets yin (and vice versa), they neutralize each other, and when yang meets yang, yang becomes excessive (the same applies to yin). Applying this theory explains our results. We found that in the yin-rich group, we found a lower association between higher intake of street foods and the possible development of clinical acne. These foods are usually fat-rich, heavily flavored and fried and are considered to be yang-rich foods. High consumption of these foods in yang-rich people can improve their acne. Conversely, in yang-rich people, acne appears in people with a high intake of desserts and fresh juices, but to a lesser extent in people with a high intake of milk or soy-based products. Because of their sweetness, desserts and fruit juices are common yang-rich foods, and high consumption of these by yang-rich people may aggravate their acne, whereas milk or soy products are commonly classified as neutral or yin-rich foods, so high consumption of these by yang-rich people may improve their acne.
We found a significant correlation between acne and the consumption of desserts and fresh fruit in the yang-sheng group, but no correlation between acne and the consumption of other sugary foods such as candy. The reason for this apparent inconsistency remains unclear. It may be that our subjects were young adults and consumed less “kid food” such as candy. Optionally, the relationship between candy intake and acne incidence may not have been detected by our analysis. This could also be a statistical artifact: the interrelationship between these variables could explain the results, as only one variable was significant in the multivariate model.
To our knowledge, this is the first time that the relationship between diet and acne has been studied using TCM methods. In terms of TCM, our results may have practical implications for the treatment of acne. Social and cultural factors can influence symptoms and clinical presentation, and our results suggest that acne patients can be treated according to the approach we demonstrated.
Our study also has several shortcomings. First, the findings of association were not necessarily related. Further prospective studies are needed to prove our results. Second, only a short dietary questionnaire was used, as only a limited amount of time was available to complete the study process. Further studies need to include more questionnaires to elicit a broader range of dietary patterns.
In conclusion, we believe that a significant correlation between diet and acne incidence can be derived using the TCM method.