A plant-based diet refers to a way of eating that primarily focuses on consuming foods derived from plants. This includes a wide variety of vegetables, fruits, beans, lentils, legumes, nuts, seeds, fungi, and whole grains. Animal products and processed foods are limited or avoided in this dietary approach.
Plant-based diets have been found to have benefits for various conditions and diseases and specific plant-based functional foods can play a role in supporting skin health. One of the targets of this dietary pattern is the gut microbiota, the community of microorganisms residing in our digestive system. Improving the health of the gut microbiota may contribute to some of the positive effects observed on overall health, including the skin.
By adopting a plant-based diet, individuals can provide their bodies with a rich array of nutrients, antioxidants, and fiber that are abundant in plant foods. These components can support overall health and may have a positive impact on the condition of the skin. However, it's important to note that individual results may vary, and maintaining a balanced diet, as well as considering other factors like skincare routines and overall lifestyle, is essential for optimal skin health.
A plant-based diet that limits or excludes animal-derived products while increasing the intake of vegetables, fruits, legumes, nuts, and cereals has shown benefits for skin health [7]. This type of diet is low in saturated fat, trans fat, and arachidonic acid while being rich in antioxidants and omega-3 fatty acids. These properties, along with the diet's anti-inflammatory effects and ability to promote weight loss, contribute to improved overall well-being for psoriatic patients. Therefore, incorporating plant-based diets as a potential therapeutic option is recommended for the management of certain psoriatic patients.
Atopic dermatitis (AD) is a common inflammatory skin disease characterized by redness, itchy bumps, and scaly patches, primarily found in areas like the hands, neck, and head [26]. It is influenced by various factors, including genetics, the environment, and immune activity. The development of AD involves the infiltration of eosinophils and T-lymphocytes, skin barrier dysfunction, changes in the skin's microbiota, abnormal immune responses, and sensitization to immunoglobulin E (IgE) [27]. The standard treatment for AD includes corticosteroids (applied topically or taken systemically), emollients, anti-inflammatory drugs, antihistamines, and immunosuppressive drugs like cyclosporine-A [28]. There is a known association between AD and food allergies, so avoiding certain foods has shown therapeutic benefits [29].
Two studies provide evidence regarding the impact of diet on atopic dermatitis (AD). In an open-trial study, a vegetarian diet was found to significantly reduce the severity of AD symptoms, as measured by the SCORAD index, which assesses erythema, edema, crusts, and excoriation. This improvement in skin inflammation was accompanied by a decrease in LDH5 activity, the number of eosinophils and neutrophils in the blood, and the synthesis of PGE2, an inflammatory mediator. The study also observed a decrease in serum IgE levels and a return to normal levels of peripheral eosinophils [30].
The intervention involved a vegetarian and low-energy diet with a daily calorie intake of 1085 kcal. The diet included fresh vegetable juice, brown rice with kelp powder, tofu, and sesame paste, administered over a period of 2 months. No adverse effects related to the vegetarian diet were reported [31]. However, further studies with larger sample sizes are needed to fully understand the anti-inflammatory effects of plant-based diets in AD.
One of the main concerns associated with vegetarian and plant-based diets is the possibility of nutritional deficiencies. However, in the mentioned study, no serious adverse events were reported, indicating that the vegetarian and low-energy diets were well-tolerated. These diets may have benefits for individuals with AD, as they provide antioxidants like vitamins C and E, which can help reduce skin inflammation. Additionally, the potential reduction in body mass index (BMI) associated with these diets may contribute to improved skin health [31].
Study Design | Participant Characteristics | Intervention Details | Outcomes | Ref |
---|---|---|---|---|
Exploratory survey study | 1206 psoriasis patients. The mean age of the sample population was 50.4, and 73% of respondents were female. | The survey contained 61 questions; the first 30 questions were from National Health and Nutrition Examination Survey; the last 31 questions focused on patient-report skin responses to dietary changes. | 72% of Pagano, 70% of vegan, and 68.9% of Paleolithic diets reported favorable skin response. The addition of fruits to the diet was protective against psoriasis, OR 0.22, p < 0.0001. | [21] |
Assessor-blind, randomized controlled trial | 303 patients between 18 and 80 years, overweight or obese, with moderate to severe chronic plaque psoriasis. | Each participant underwent an introductory session with a dietitian. Subjects were instructed to perform sessions of continuous aerobic physical exercise for at least 40 min three times a week. Compared how psoriasis severity was affected by either a 20-week quantitative or qualitative dietary plan associated with physical exercise for weight loss. | Reduction of PASI score by 48% in the dietary intervention and 25.5% in the information-only. | [23] |
Cross-sectional study | 56,896 participants. The mean age was 55.8, and 22,577 were female. | First, the researchers sent out a digital questionnaire focused on atopic dermatitis (AD). After collecting the responses, they administered another questionnaire to extract data on lifestyle factors, such as smoking, alcohol consumption, stress, obesity, physical activity, and diet (participants were dichotomized into vegetarian/vegan and nonvegetarian/nonvegan), and finally analyzed the association between lifestyle factors and presence of AD. | No associations were observed with abdominal obesity, physical activity, diet quality, or a vegetarian/vegan diet. | [81] |
Controlled clinical trial | 19 patients with atopic dermatitis. The mean age was 25.5. | The patients were exposed to a low-energy diet, no pharmacotherapy. The SCORAD indices were noted by 2 dermatologists. Blood and urine samples were collected at weeks 0.4 and 8. The 24 h void urine was collected and kept frozen at −80 °C. | SCORAD significant reduction from 6.1 ± 2.8 at week 0 to 2.7 ± 2.8 at week 8. | [31] |
Clinical trials | Twenty patients (6 males and 14 females) aged 15 to 36 years (average: 25 years) with AD varying in severity from mild to serious. All patients fulfilled the criteria for atopic dermatitis (AD) established by Hanifin and Rajka. |
All patients followed the same meal plan throughout the study. The diet included a glass of fresh vegetable juice for breakfast, followed by brown rice porridge, kelp powder, tofu, and sesame paste for both lunch and dinner. In addition, a daily intake of 2.5 g of non-refined salt was included in the diet. Instead of regular water, the patients were provided with persimmon leaf tea. This treatment regimen was followed for two months. | Reduction in SCORAD index from 49.9 ± 18.6 to 27.4 ± 16.8 (p = 0.001), diminution in peripheral eosinophil count 423 ± 367 to 213 ± 267 (p = 0.01), reduction in monocyte PGE2 synthesis 2886 ± 1443 to 1390 ± 773 (p = 0.001). | [30] |
Case-control cross-sectional questionnaire study | 57 acne vulgaris patients as cases and 57 participants as controls. Aged 14 and above and were seeking medical consultations at a private clinic. | The Comprehensive Acne Severity Scale (CASS) grading system was used to grade acne severity. Cases were defined as patients with CASS grade of two to five and controls with CASS grade 0 or 1. Thereafter, controls were recruited and matched by age, gender, and ethnicity. A self-administered questionnaire was used to collect information regarding the participants’ dietary intake and cigarette smoking habits. | No significant associations were found between dietary patterns and acne; on the other hand, they only found an association between milk and chocolate consumption and acne. | [35] |
Case-control study | 279 acne patients and 279 controls aged 10–24 years. | Acne severity was determined by a dermatologist using the Global Acne Severity Scale. Epidemiological data were collected with a pre-structured questionnaire. The food consumption habits were recorded using a food frequency questionnaire. Investigated food included whole milk, low-fat milk, cream of milk, ice cream, cheese, chocolate, cake, potatoes, fresh fruit, fresh vegetable, meat, chicken, and egg. Consumption habit data were collected for 8 months. | The study found that consuming whole milk at least three days a week was significantly associated with moderate to severe acne (OR = 2.36, 95% CI, 1.39–4.01). The association was slightly weaker for low-fat milk (OR 1.95, 95% CI, 1.10–3.45). | [38] |
A prospective case-control study | 460 subjects of both sexes, 230 patients with acne vulgaris, and 230 healthy volunteers were included as controls. | Acne severity in patients was classified as mild, moderate, and severe according to the classification of the American Academy of Dermatology. Two formulated tools were used in the study. First tool: interview questionnaires that included two parts (sociodemographic data, anthropometric measurements, and questions related to food habits, drug intake, and diet history). Second tool: a recommended diet regimen. | Significantly decreased consumption of vegetables was noticed among severe and moderate acne patients compared with mild ones. | [39] |
Clinical-trial study | Healthy postmenopausal women aged 50 to 70 (N = 28). Inclusion criteria were Fitzpatrick skin type I, II, or III and a body mass index (BMI) between 18.5 and 35 kg/m2. | Participants were randomized by block design into an open-label, two-arm parallel clinical trial consuming either 85 g or 250 g of Ataulfo mango, four times per week for 16 weeks. | 0.5 cup frozen Ataulfo mango consumption decreases facial wrinkle depth and severity and photodamage induced by UVB. Serum triglycerides decreased. A higher amount of mango (1.5 cups) showed the contrary effect. | [44] |
Randomized clinical trial | Thirty-one participants (all postmenopausal females) with a Fitzpatrick skin type 1 or 2. | Consisted of a total of five study visits following a 4-week dietary washout period: baseline, 4, 8, and 16 weeks. The patients were randomized into two intervention groups: almond group and control group. Almond group received an average of 340 kcal/day of almonds. | There were no significant differences in sebum production and transepidermal water loss between the almond and control groups. Wrinkle severity and wrinkle width were significantly decreased in the almond group compared with the control intervention. | [47] |
Randomized- blinded | 56 postmenopausal women with a Fitzpatrick skin type I or II. | A total of 56 female participants were randomly assigned to two intervention groups: the almond group, which received almonds, and the control group, which received a calorie-matched snack. In the almond group, the dose of almonds provided accounted for 20% of the total energy in the participants’ diet. The almond snack group received approximately 2 g of sugars per day, whereas the control snack group received approximately 8 g of sugars per day that was additional to their regular food intake. 24 weeks. | Reduction in the average severity of wrinkles compared to the baseline. Additionally, intensity of facial pigmentation decreased in the almond group. | [48] |
Randomized parallel group | 39 women with a Fitzpatrick skin type II–IV. | The patients were randomized into two intervention groups: avocado and control. The participants either consumed one avocado daily or no avocado based on randomization performed. 8 weeks. | Daily consumption of one avocado per day for 8 weeks improved firmness and elasticity and reduced the tiring of repeat stretching of the forehead skin. | [50] |
Case-control | 30 patients with AD (according to the criteria for the diagnosis of AD established by the Japanese Dermatological Association) less than 20 years of age and age- and sex-matched control subjects (68 healthy individuals). | A questionnaire survey was conducted for 1 week, and then fecal specimens and 24 h skin secretion specimens were collected from all subjects. Fecal microflora, fecal IgA levels, and IgA concentrations in the skin were analyzed. The data for the 2 groups (i.e., patients with AD and healthy control subjects) were compared. | The counts of Bifidobacterium were significantly lower in patients with AD than in healthy control subjects (9.75 ± 0.68 vs. 10.10 ± 0.50, p < 0.05). Percentages of Bifidobacterium were significantly lower in patients with severe skin symptoms than in those with mild skin symptoms (40 ± 6% vs. 19 ± 6%, p < 0.05). In addition, the frequency of occurrence of Staphylococcus was significantly higher in patients with AD than in healthy control subjects (83% vs. 59%, p < 0.05). | [80] |
Case-control | 21 psoriasis patients from a Brazilian referral dermatology service and 24 controls. | A stool sample was collected from each participant at the time of inclusion in the study, and the samples were analyzed by sequencing the 16S rRNA gene. | Patients with psoriasis showed higher levels of the Dialister genus and the species Prevotella copri compared to the control group. Conversely, there was a decrease in the Ruminococcus, Lachnospira, and Blautia genera, as well as the Akkermansia muciniphila species, in the psoriasis group compared to the control group. Additionally, individuals with psoriasis had lower diversity in their gut microbiota compared to the control group. | [79] |
Case report | 63-year-old woman with ulcerations on both lower legs and diagnosed livedoid vasculopathy by biopsy. | The patient adopted a whole-food plant-based diet (WFPB) as a potential treatment with no other form of treatment. | The symptoms were initially completely resolved, but they reappeared later due to a lack of adherence to a proper diet. | [82] |
Case report | 58-year-old female patient with pemphigus vulgaris and type 2 diabetes mellitus. | Incorporated a change in lifestyle with different approaches, including hydrotherapy, yoga, a vegetarian diet, herbal preparations, and massage. | The patient was successfully weaned off all medications and had complete remission from PV. | [83] |
Cross-sectional | They measured skin autofluorescence (SAF) in 332 adult hemodialysis patients who were dialyzing in north central London. | SAF was measured in 332 adult dialysis patients. | SAF was lower in the twenty-seven vegetarians than it was in the non-vegetarians. | [84] |
Observational retrospective | 21 omnivore patients, 21 vegan patients, with surgical excision of melanoma. | The assessment of postsurgical complications and the quality of scars was conducted using a modified version of the Scar Cosmesis Assessment and Rating (SCAR) scale. | Wound diastasis was more frequent in vegans (p = 0.008). Higher modified SCAR score than omnivores (p < 0.001), worst scar spread (p < 0.001), more frequent atrophic scars (p < 0.001), and worse overall impression (p < 0.001) were observed in vegans. | [29] |
Study Design | Participant Characteristics | Intervention Details | Outcomes | Ref |
Exploratory survey study | 1206 psoriasis patients. The mean age of the sample population was 50.4, and 73% of respondents were female. | The survey contained 61 questions; the first 30 questions were from National Health and Nutrition Examination Survey; the last 31 questions focused on patient-report skin responses to dietary changes. | 72% of Pagano, 70% of vegan, and 68.9% of Paleolithic diets reported favorable skin response. The addition of fruits to the diet was protective against psoriasis, OR 0.22, p < 0.0001. | [21] |
Assessor-blind, randomized controlled trial | 303 patients between 18 and 80 years, overweight or obese, with moderate to severe chronic plaque psoriasis. | Each participant underwent an introductory session with a dietitian. Subjects were instructed to perform sessions of continuous aerobic physical exercise for at least 40 min three times a week. Compared how psoriasis severity was affected by either a 20-week quantitative or qualitative dietary plan associated with physical exercise for weight loss. | Reduction of PASI score by 48% in the dietary intervention and 25.5% in the information-only. | [23] |
Cross-sectional study | 56,896 participants. The mean age was 55.8, and 22,577 were female. | First, the researchers sent out a digital questionnaire focused on atopic dermatitis (AD). After collecting the responses, they administered another questionnaire to extract data on lifestyle factors, such as smoking, alcohol consumption, stress, obesity, physical activity, and diet (participants were dichotomized into vegetarian/vegan and nonvegetarian/nonvegan), and finally analyzed the association between lifestyle factors and presence of AD. | No associations were observed with abdominal obesity, physical activity, diet quality, or a vegetarian/vegan diet. | [81] |
Controlled clinical trial | 19 patients with atopic dermatitis. The mean age was 25.5. | The patients were exposed to a low-energy diet, no pharmacotherapy. The SCORAD indices were noted by 2 dermatologists. Blood and urine samples were collected at weeks 0.4 and 8. The 24 h void urine was collected and kept frozen at −80 °C. | SCORAD significant reduction from 6.1 ± 2.8 at week 0 to 2.7 ± 2.8 at week 8. | [31] |
Clinical trials | Twenty patients (6 males and 14 females) aged 15 to 36 years (average: 25 years) with AD varying in severity from mild to serious. All patients fulfilled the criteria for atopic dermatitis (AD) established by Hanifin and Rajka. |
All patients followed the same meal plan throughout the study. The diet included a glass of fresh vegetable juice for breakfast, followed by brown rice porridge, kelp powder, tofu, and sesame paste for both lunch and dinner. In addition, a daily intake of 2.5 g of non-refined salt was included in the diet. Instead of regular water, the patients were provided with persimmon leaf tea. This treatment regimen was followed for two months. | Reduction in SCORAD index from 49.9 ± 18.6 to 27.4 ± 16.8 (p = 0.001), diminution in peripheral eosinophil count 423 ± 367 to 213 ± 267 (p = 0.01), reduction in monocyte PGE2 synthesis 2886 ± 1443 to 1390 ± 773 (p = 0.001). | [30] |
Case-control cross-sectional questionnaire study | 57 acne vulgaris patients as cases and 57 participants as controls. Aged 14 and above and were seeking medical consultations at a private clinic. | The Comprehensive Acne Severity Scale (CASS) grading system was used to grade acne severity. Cases were defined as patients with CASS grade of two to five and controls with CASS grade 0 or 1. Thereafter, controls were recruited and matched by age, gender, and ethnicity. A self-administered questionnaire was used to collect information regarding the participants’ dietary intake and cigarette smoking habits. | No significant associations were found between dietary patterns and acne; on the other hand, they only found an association between milk and chocolate consumption and acne. | [35] |
Case-control study | 279 acne patients and 279 controls aged 10–24 years. | Acne severity was determined by a dermatologist using the Global Acne Severity Scale. Epidemiological data were collected with a pre-structured questionnaire. The food consumption habits were recorded using a food frequency questionnaire. Investigated food included whole milk, low-fat milk, cream of milk, ice cream, cheese, chocolate, cake, potatoes, fresh fruit, fresh vegetable, meat, chicken, and egg. Consumption habit data were collected for 8 months. | The study found that consuming whole milk at least three days a week was significantly associated with moderate to severe acne (OR = 2.36, 95% CI, 1.39–4.01). The association was slightly weaker for low-fat milk (OR 1.95, 95% CI, 1.10–3.45). | [38] |
A prospective case-control study | 460 subjects of both sexes, 230 patients with acne vulgaris, and 230 healthy volunteers were included as controls. | Acne severity in patients was classified as mild, moderate, and severe according to the classification of the American Academy of Dermatology. Two formulated tools were used in the study. First tool: interview questionnaires that included two parts (sociodemographic data, anthropometric measurements, and questions related to food habits, drug intake, and diet history). Second tool: a recommended diet regimen. | Significantly decreased consumption of vegetables was noticed among severe and moderate acne patients compared with mild ones. | [39] |
Clinical-trial study | Healthy postmenopausal women aged 50 to 70 (N = 28). Inclusion criteria were Fitzpatrick skin type I, II, or III and a body mass index (BMI) between 18.5 and 35 kg/m2. | Participants were randomized by block design into an open-label, two-arm parallel clinical trial consuming either 85 g or 250 g of Ataulfo mango, four times per week for 16 weeks. | 0.5 cup frozen Ataulfo mango consumption decreases facial wrinkle depth and severity and photodamage induced by UVB. Serum triglycerides decreased. A higher amount of mango (1.5 cups) showed the contrary effect. | [44] |
Randomized clinical trial | Thirty-one participants (all postmenopausal females) with a Fitzpatrick skin type 1 or 2. | Consisted of a total of five study visits following a 4-week dietary washout period: baseline, 4, 8, and 16 weeks. The patients were randomized into two intervention groups: almond group and control group. Almond group received an average of 340 kcal/day of almonds. | There were no significant differences in sebum production and transepidermal water loss between the almond and control groups. Wrinkle severity and wrinkle width were significantly decreased in the almond group compared with the control intervention. | [47] |
Randomized- blinded | 56 postmenopausal women with a Fitzpatrick skin type I or II. | A total of 56 female participants were randomly assigned to two intervention groups: the almond group, which received almonds, and the control group, which received a calorie-matched snack. In the almond group, the dose of almonds provided accounted for 20% of the total energy in the participants’ diet. The almond snack group received approximately 2 g of sugars per day, whereas the control snack group received approximately 8 g of sugars per day that was additional to their regular food intake. 24 weeks. | Reduction in the average severity of wrinkles compared to the baseline. Additionally, intensity of facial pigmentation decreased in the almond group. | [48] |
Randomized parallel group | 39 women with a Fitzpatrick skin type II–IV. | The patients were randomized into two intervention groups: avocado and control. The participants either consumed one avocado daily or no avocado based on randomization performed. 8 weeks. | Daily consumption of one avocado per day for 8 weeks improved firmness and elasticity and reduced the tiring of repeat stretching of the forehead skin. | [50] |
Case-control | 30 patients with AD (according to the criteria for the diagnosis of AD established by the Japanese Dermatological Association) less than 20 years of age and age- and sex-matched control subjects (68 healthy individuals). | A questionnaire survey was conducted for 1 week, and then fecal specimens and 24 h skin secretion specimens were collected from all subjects. Fecal microflora, fecal IgA levels, and IgA concentrations in the skin were analyzed. The data for the 2 groups (i.e., patients with AD and healthy control subjects) were compared. | The counts of Bifidobacterium were significantly lower in patients with AD than in healthy control subjects (9.75 ± 0.68 vs. 10.10 ± 0.50, p < 0.05). Percentages of Bifidobacterium were significantly lower in patients with severe skin symptoms than in those with mild skin symptoms (40 ± 6% vs. 19 ± 6%, p < 0.05). In addition, the frequency of occurrence of Staphylococcus was significantly higher in patients with AD than in healthy control subjects (83% vs. 59%, p < 0.05). | [80] |
Case-control | 21 psoriasis patients from a Brazilian referral dermatology service and 24 controls. | A stool sample was collected from each participant at the time of inclusion in the study, and the samples were analyzed by sequencing the 16S rRNA gene. | Patients with psoriasis showed higher levels of the Dialister genus and the species Prevotella copri compared to the control group. Conversely, there was a decrease in the Ruminococcus, Lachnospira, and Blautia genera, as well as the Akkermansia muciniphila species, in the psoriasis group compared to the control group. Additionally, individuals with psoriasis had lower diversity in their gut microbiota compared to the control group. | [79] |
Case report | 63-year-old woman with ulcerations on both lower legs and diagnosed livedoid vasculopathy by biopsy. | The patient adopted a whole-food plant-based diet (WFPB) as a potential treatment with no other form of treatment. | The symptoms were initially completely resolved, but they reappeared later due to a lack of adherence to a proper diet. | [82] |
Case report | 58-year-old female patient with pemphigus vulgaris and type 2 diabetes mellitus. | Incorporated a change in lifestyle with different approaches, including hydrotherapy, yoga, a vegetarian diet, herbal preparations, and massage. | The patient was successfully weaned off all medications and had complete remission from PV. | [83] |
Cross-sectional | They measured skin autofluorescence (SAF) in 332 adult hemodialysis patients who were dialyzing in north central London. | SAF was measured in 332 adult dialysis patients. | SAF was lower in the twenty-seven vegetarians than it was in the non-vegetarians. | [84] |
Observational retrospective | 21 omnivore patients, 21 vegan patients, with surgical excision of melanoma. | The assessment of postsurgical complications and the quality of scars was conducted using a modified version of the Scar Cosmesis Assessment and Rating (SCAR) scale. | Wound diastasis was more frequent in vegans (p = 0.008). Higher modified SCAR score than omnivores (p < 0.001), worst scar spread (p < 0.001), more frequent atrophic scars (p < 0.001), and worse overall impression (p < 0.001) were observed in vegans. | [29] |