Biophysical properties of redness-prone skin in Korean women.

BACKGROUND: Facial skin redness can have a negative impact on the quality of life. In this study, we investigated the skin biophysical parameters associated with facial skin redness as a function of aging. METHODS: Our aims were as follows: (1) to understand the impact of non-pathological facial skin redness on the quality of life of Korean women through a survey; and (2) compare skin biophysical properties between women with and without facial skin redness. RESULTS: Women aged between 20 and 39 years perceived their own facial skin redness at a higher rate than those aged ≥40 years. In addition, in redness-prone women, the intensity of skin redness and skin surface perfusion were higher, while skin hydration was lower regardless of age. In redness-prone women aged ≥40 years, the values for transepidermal water loss, elasticity, and skin thickness were lower, and the mean pore depth was greater. Facial redness intensity was higher, and the distribution was wider in redness-prone younger women, while only redness intensity increased in the older age group. CONCLUSIONS: Overall, redness-prone women aged ≥40 years had weaker skin properties. Our study indicated the age-related biophysical characteristics of non-pathological facial skin redness. We believe that our findings will help improve its negative effects.

In vivo method to evaluate antioxidative activity using UVA-induced carbonylated protein on human skin.

BACKGROUND: Skin is continuously exposed to oxidative stress caused by reactive oxygen species (ROS) produced by the ultraviolet (UV) light, and it is important to evaluate the antioxidant activity. Carbonylated proteins (CPs) are candidate markers of oxidative modification as a result from the ROS. We aimed to develop the CP-based method to assess the efficacy of antioxidants in human skin. METHODS: Ten healthy females were enrolled in the study to determine the UVA dosage for CP production, and another 10 females were included to evaluate the antioxidative activity. The stratum corneum was collected from test skin using D-Squame tape, and CPs from the SC were stained by fluorescence labeling and observed using a fluorescence microscope. RESULTS: CP level significantly increased with UVA irradiation from 15J/cm2 to 50J/cm2 compared to the control (non-UVA) area. CP production significantly increased by 34.38% and 35.22% in UVA irradiation and squalene (vehicle) areas. 5% α-tocopherol and ß-carotene significantly increased the CP production by 20.77% and 19.34% after 2 hours of 30J of UVA irradiation compared to control area. Inhibition rate of CPs in 5% α-tocopherol and 5% ß-carotene showed 41.45% and 45.37% after 2 hours of UVA irradiation. CONCLUSION: This study developed the simple, visual, and direct in vivo method to evaluate the antioxidative activity for products in human skin by measuring the CP level as an oxidative modification caused by UVA-induced ROS generation.

Evaluation of facial skin age based on biophysical properties in vivo.

OBJECTIVE: The evaluation of skin age, reflecting overall facial characteristics, has not been established. Previous studies focused on visual assessment or individual-specific feature such as wrinkles or skin color. We studied the evaluation model of skin age index (SAI) including the overall aging features including wrinkles, skin color, pigmentation, elasticity, and hydration. METHODS: Total 300 healthy women aged between 20 and 69 years included in this study. Pearson correlation analysis performed to identify the key factors among the biophysical properties with aging and developed the prediction model of SAI. Statistical regression analysis and machine learning technique applied to build the prediction model using the coefficient of determination (R2 ) and root mean square error (RMSE). Validation study of the SAI model performed on 24 women for 6 weeks application with anti-aging product. RESULTS: Prediction model of SAI consisted of skin elasticity, wrinkles, skin color (brightness, Pigmented spot, and Uv spot), and hydration, which are major features for aging. The cforest model to assess a SAI using machine learning identified the highest R2 and lowest RMSE compared to other models, such as svmRadial, gaussprRadial, blackboost, rpart, and statistical regression formula. The cforest prediction model confirmed a significant decrease of predicted SAI after 6 weeks of application of anti-aging product. CONCLUSION: We developed a prediction model to evaluate a SAI using machine learning, and led to accurate predicted age for overall clinical aging. This model can a good standard index for evaluating facial skin aging and anti-aging products.

Layering sunscreen with facial makeup enhances its sun protection factor under real-use conditions.

BACKGROUND: The proper application of sunscreen is important to ensure protection of the skin against ultraviolet (UV) damage. Sunscreens are used in various ways in real world situations, which alters their UV protection efficacy. In this study, we simulated typical consumer use of sunscreen, which is often sequentially covered with facial makeup, in a laboratory study. METHODS: We compared the sun protection factors (SPF) of sunscreen and makeup products after consecutive layering of the products. RESULTS: The SPF of each sunscreen and makeup product was dramatically lower than stated on the label upon application of a typical amount used by a consumer, which is lower than recommended. For high-SPF products, the drop in effective protection was proportionally greater than those for the low-SPF products upon application of lower doses. However, layering sunscreen and makeup products greatly increased the effective SPF compared with that achieved by single application of each product, even when the amount of each product used was below the recommended level. CONCLUSION: Layering sunscreen with makeup may compensate for insufficient sunscreen application in real-life conditions by providing an additional source of UV protection and improving the homogeneity of coverage. Our results suggest that recommending consecutive application of sunscreen and makeup products may be a practical and useful approach to improving UV protection that would not require additional steps in the facial care routines of many individuals.

Effects of anti-wrinkle and skin-whitening fermented black ginseng on human subjects and underlying mechanism of action.

The aim of this study was to determine the effects of anti-wrinkle and skin-whitening of fermented black ginseng (FBG) in human subjects and to examine underlying biochemical mechanisms of action. A clinical study was performed to evaluate efficacy and safety using a 1% FBG cream formulation. Twenty-three subjects were recruited and instructed to apply control or FBG creams each on half of their face twice daily for 8 weeks. After 8 weeks FBG cream significantly reduced appearance of eye wrinkles compared to prior to exposure and control cream. Skin color was significantly brightened using FBG cream in comparison with control cream. To determine the mechanism of actions involved in anti-wrinkle and skin-whitening effects various concentrations of FBG were applied to human fibroblast CCD-986sk and mouse melanoma B16F1 cells. Collagen synthesis in CCD-986sk cells was improved significantly at 1, 3, 10, or 30 µg/ml of FBG. At 30 µg/ml, FBG significantly inhibited (73%) collagenase, and matrix metalloproteinase-1 (MMP-1) compared to control. Tyrosinase activity and DOPA (3,4-dihydroxy-L-phenylalanine) oxidation were significantly decreased at all tested concentrations. Melanin production in B16F1 cells was concentration-dependently reduced 15% to 60% by all concentrations of FBG. These results suggested that a 1% FBG cream exerted anti-wrinkle and skin-whitening effects.

Effects of anti-wrinkle and skin-whitening fermented black ginseng on human subjects and underlying mechanism of action.

The aim of this study was to determine the effects of anti-wrinkle and skin-whitening of fermented black ginseng (FBG) in human subjects and to examine underlying biochemical mechanisms of action. A clinical study was performed to evaluate efficacy and safety using a 1% FBG cream formulation. Twenty-three subjects were recruited and instructed to apply control or FBG creams each on half of their face twice daily for 8 weeks. After 8 weeks, FBG cream significantly reduced the appearance of eye wrinkles compared to prior to exposure and control cream. Skin color was significantly brightened using FBG cream in comparison with a control cream. To determine the mechanism of actions involved in anti-wrinkle and skin-whitening effects various concentrations of FBG were applied to human fibroblast CCD-986sk and mouse melanoma B16F1 cells. Collagen synthesis in CCD-986sk cells was improved significantly at 1, 3, 10, or 30 µg/ml of FBG. At 30 µg/ml, FBG significantly inhibited (73%) collagenase, and matrix metalloproteinase-1 (MMP-1) compared to control. Tyrosinase activity and DOPA (3,4-dihydroxy-L-phenylalanine) oxidation were significantly decreased at all tested concentrations. Melanin production in B16F1 cells was concentration-dependently reduced from 15% to 60% by all concentrations of FBG. These results suggested that a 1% FBG cream exerted anti-wrinkle and skin-whitening effects.

Benzophenone-3 and benzophenone-8 exhibit obesogenic activity via peroxisome proliferator-activated receptor γ pathway.

Benzophenone-3 (BP-3) and benzopenone-8 (BP-8) are commonly used ultraviolet (UV) filter ingredients in diverse sunscreen products. Recently, the obesogenic activity of avobenzone, a long wave UV A filter, was elucidated in the adipogenesis model of human bone marrow mesenchymal stem cells (hBM-MSCs). In this study, the obesogenic potentials of BP-3 and BP-8 were investigated because of their chemical similarity to avobenzone. During the adipogenesis in hBM-MSCs, BP-3 and BP-8 (EC50, 25.05 and 43.20 µM, respectively) potently promoted adiponectin secretion than avobenzone (EC50, 72.69 µM). In target identification, both BP-3 and BP-8 directly bound to peroxisome proliferator-activated receptor γ (PPARγ), which was associated with the recruitment of steroid receptor coactivator-2 (SRC-2). BP-3 functioned as a PPARγ full agonist whereas BP-8 was a PPARγ partial agonist. In addition, BP-3 and BP-8 significantly increased the gene transcription of PPARα, PPARγ, and major lipid metabolism-associated enzymes in human epidermal keratinocytes, a major target site of UV filters in human skin. This study suggests that BP-3 and BP-8 are obesogenic environmental chemicals similar to phthalates, bisphenols, and organotins.

Antiaging Potential of Fucoxanthin Concentrate Derived from Phaeodactylum tricornutum.

The aim of the study was to investigate the potential of a fucoxanthin concentrate prepared from Phaeodactylum tricornutum as a wrinkle care cosmetic agent. The concentrate (up to 25 µg/ml) did not affect the proliferation of human fibroblasts. In addition, the concentrate significantly increased procollagen synthesis in the fibroblasts at 12.5 and 25 µg/ml; however, it significantly decreased the expression of matrix metalloproteinase (MMP)-1, MMP-2, and MMP-9 at 25 µg/ml. In a follow-up study, a wrinkle care cream containing 0.03% of fucoxanthin concentrate was prepared and tested in women (aged 35-50 years, n = 21) for 8 weeks. The cream was applied twice daily. Safety assessment of the cream was carried out visually. In addition, interviews were conducted to investigate if adverse events such as erythema, edema, scaling, itching, stinging, burning, tightness, or prickling had occurred. No symptoms that threaten skin safety were reported. Evaluation of wrinkles around the eyes using the replica method showed a statistically significant decrease in wrinkles at week 8. Moreover, skin moisture and elasticity increased significantly from week 4. These results suggest that the fucoxanthin concentrate has no adverse effects on the skin and can be used as an active ingredient in wrinkle care cosmetics.

CXCL14 downregulation in human keratinocytes is a potential biomarker for a novel in vitro skin sensitization test.

To elucidate the roles of epidermal keratinocytes in the toxicological outcomes of chemically induced contact dermatitis, genome-scale transcriptional analyses were performed using normal human keratinocytes (NHKCs) treated with 10 µM sodium lauryl sulfate (SLS) or 5 µM urushiol. In Gene Ontology (GO) enrichment analyses, SLS- and urushiol-induced upregulated DEGs are commonly associated with the regulation of pro-inflammatory responses and epidermal differentiation processes in NHKCs whereas cellular protein metabolic process was also identified as a commonly downregulated DEG signature. Among the downregulated DEGs, CXCL14 was investigated as a potential biomarker for a new in vitro skin sensitization test using OECD TG429 reference chemicals. CXCL14 was significantly downregulated in NHKCs in response to 62.5% of the OECD TG429 sensitizers in a concentration-dependent manner. When the sensitizer-induced upregulation of chemokine CXCL8 was included in the analysis, 87.5% of the OECD TG429 reference sensitizing chemicals significantly induced either CXCL8 upregulation or CXCL14 downregulation in NHKCs. Only one OECD TG429 reference non-sensitizer changed the constitutive CXCL14 expression in NHKCs whereas five out of six non-sensitizers altered CXCL8 production. The reference irritating non-sensitizer SLS caused a false-positive outcome. The downregulation of constitutively expressed CXCL14 was regulated by both the MAPK/ERK and JAK3/STAT6 pathways in NHKCs. CXCL14 can be used as a mechanism-based biomarker in the development of in vitro skin sensitization tests and may help improve the distinction between allergenic sensitizers and non-sensitizers.

A novel in vivo test method for evaluating the infrared radiation protection provided by sunscreen products.

BACKGROUND: Infrared radiation (IR) exposure generates reactive oxygen species and induces matrix metalloproteinase-1 expression in human skin. Moreover, while not as acute as ultraviolet radiation, repeated infrared irradiation can result in the photoaging of skin. Broad-spectrum sunscreens can protect skin from IR, but no human in vivo test methods for the evaluation of sunscreens' IR protection effect have been developed. We aimed to develop such a method. MATERIALS AND METHODS: We included 155 Korean subjects in our three-part clinical study. The IR reflectance of subjects' skin was measured using a benchtop model of an IR light source and a reflectance measuring probe. We measured the IR reflectance in relation to skin color and hydration level to set up our experimental conditions. We then calculated the infrared protection factors (IPFs) of cosmetic emulsions as the IR reflectance ratio between cosmetic sunscreen-applied skin and non-sunscreen-applied skin and assessed the relationship between IPFs and the amount of sunscreen ingredients. Finally, this method was validated using several commercial sunscreen cosmetics. RESULTS: Skin color and hydration level did not influence the IR reflectance of subjects' skin. The IPFs of cosmetic sunscreens showed a positive correlation with the amount of inorganic sunscreen ingredients. CONCLUSION: In this study, we developed a simple, fast, and ethically acceptable human in vivo test method for evaluating the IPFs of cosmetic sunscreens.

Evaluation of factors triggering sensitive scalp in Korean adult women.

BACKGROUND: The scalp care market is growing rapidly and research into the factors associated with sensitive scalp is performed in many countries. However, to the best of our knowledge, no previous study has examined the factors triggering sensitive scalp in Korean women. Thus, the aim of our study was to establish objective standards for sensitive scalp, investigate factors that trigger this condition, and determine the ratio of sensitive scalp in Korean women. METHODS: A total of 125 Korean adult women participated in the study. The participants answered the questionnaire, had their scalp temperature measured, and the sensitive scalp condition was evaluated and analyzed. RESULTS: Compared to the non-sensitive scalp (NS) group, the sensitive scalp (SS) group had a significantly higher average temperature and increased heat sensation, dandruff, erythema in the scalp, past history of atopy, history of hair loss, medical history of scalp disease, concern for scalp care, and interest in mild products and frequency of use. The majority of participants in the SS group had a dry scalp, and itching was common. CONCLUSION: This study may help us to understand the characteristics of the sensitive scalp in Korean females and determine factors associated with triggering a sensitive scalp.

A long-wave UVA filter avobenzone induces obesogenic phenotypes in normal human epidermal keratinocytes and mesenchymal stem cells.

Avobenzone is the most commonly used ultraviolet (UV) A filter ingredient in sunscreen. To investigate the biological activity of avobenzone in normal human epidermal keratinocytes (NHEKs), the genome-scale transcriptional profile of NHEKs was performed. In this microarray study, we found 273 up-regulated and 274 down-regulated differentially expressed genes (DEGs) in NHEKs treated with avobenzone (10 µM). Gene Ontology (GO) enrichment analysis showed that avobenzone significantly increased the DEGs associated with lipid metabolism in NHEKs. In addition, avobenzone increased the gene transcription of peroxisome proliferator-activated receptor γ (PPARγ) and fatty acid binding protein 4 in NHEKs, implicating that avobenzone may be one of the metabolic disrupting obesogens. To confirm the obesogenic potential, we examined the effect of avobenzone on adipogenesis in human bone marrow mesenchymal stem cells (hBM-MSCs). Avobenzone (EC50, 14.1 µM) significantly promoted adipogenesis in hBM-MSCs as its positive control obesogenic chemicals. Avobenzone (10 µM) significantly up-regulated mRNA levels of PPARγ during adipogenesis in hBM-MSCs. However, avobenzone did not directly bind to PPARγ and the avobenzone-induced adipogenesis-promoting activity was not affected by PPARγ antagonists T0070907 and GW9662. Therefore, avobenzone promoted adipogenesis in hBM-MSCs through a PPARγ-independent mechanism. This study suggests that avobenzone functions as a metabolic disrupting obesogen.

Age-related biophysical changes of the epidermal and dermal skin in Korean women.

INTRODUCTION: The clinical characteristics of skin were investigated to study the inter-relationship and changes in the biophysical properties of the epidermal and dermal layers associated with aging using noninvasive methods. METHODS: Our study included 100 healthy women aged between the early 20s and late 60s. Biophysical characteristics of skin such as color (brightness and spots), transparency, wrinkle on crow's feet, elasticity, hydration, sebum content, glossiness, and transepidermal water loss measured under controlled conditions. RESULTS: This study performed in a Korean population demonstrated that aging significantly affects human skin in terms of parameters such as wrinkles, skin color, elasticity, and epidermal hydration. Age-related changes in skin hydration showed varying patterns between the epidermis and dermis. Skin color showed heterogeneous characteristics between the upper and lower epidermal layers associated with aging. Skin elasticity and wrinkles were observed to show and inversely proportional relationship in the early 40s. CONCLUSIONS: We confirmed the significant influence of aging on the biophysical properties of skin and determined the distinct age-related biophysical changes in the epidermal and dermal layers of skin using noninvasive method. This study indicates the need for further research to investigate the distinctive age-related changes in characteristics of the epidermal and dermal layers of human skin.

Evaluation of human electroencephalogram change for sensory effects of fragrance.

BACKGROUND: The stabilizing effect of lavender and the arousal effect of peppermint essential oils are acknowledged and used widely in aromatherapy and the cosmetics industry. However, no evaluation method confirms the effects of essential oils through quantitative and objective electroencephalogram (EEG) results; instead, only a psychological and subjective method exists. Therefore, this study aims to create a new emotional cosmetic evaluation paradigm using EEG values. Moreover, it enables quantitative interpretation of the results in addition to the subjective survey outcomes. METHODS: For this study, 12 healthy female Korean participants were recruited and three fragrances were used. The EEG results were collected for 3 minutes (1 minute each before, during, and after inhalation of every fragrance). RESULTS: The quantitative EEG outcomes indicate changes in the participant's brainwaves before and after inhalation. Significant changes in the EEG were observed. Based on the results, the effects of fragrances were confirmed to be stabilizing for lavender, and arousing for peppermint and coffee aroma. Furthermore, the subjective questionnaire results indicate similar tendency as that of the quantitative EEG results. CONCLUSION: In addition to psychological and subjective assessments, our emotional evaluation method can verify the cosmetic fragrance effects through quantitative and objective results.

Different Cosmetic Habits Can Affect the Biophysical Profile of Facial Skin: A Study of Korean and Chinese Women.

BACKGROUND: Previous studies on the age-, climate, and skin care habit-related changes of biophysical parameters have mainly focused on Caucasians, and studies on Asians are in paucity. OBJECTIVE: This study was aimed to investigate the variations of cutaneous biophysical parameters in Chinese and Korean women (northeast Asians) and to assess the association between those parameters and age, climate, and cosmetic habits. METHODS: A cross-sectional study included 361 healthy Chinese and Korean women between 18 and 49 years of age in 4 cities (Guangzhou, Nanjing, and Shijiazhuang in China, and Suwon in Korea). We measured skin surface temperature, hydration, transepidermal water loss (TEWL), sebum, elasticity, skin pore, wrinkle, and skin tone (brightness) using non-invasive instruments. Demographic profiles and cosmetic habits were assessed using a questionnaire. RESULTS: Skin elasticity and tone decreased, and pore size and wrinkle increased with age. Subjects in Suwon (Korean) showed higher hydration level, lower TEWL and lower sebum, less severe wrinkle and brighter skin than those in the 3 cities in China. After adjusting for age and region, using sunscreen everyday, wearing base makeup daily, and using moisturizers improved hydration, TEWL, and elasticity significantly. CONCLUSION: Women in Suwon (Korea) were found to have a better profile of biophysical parameters than women in the 3 Chinese cities, which might be attributed to cosmetic habits, besides age and climatic factors. The fact that appropriate cosmetic habits are associated with favorable skin biophysical parameters underscores the importance of daily skin care routine in preserving skin functions.

Biophysical properties of striae rubra and striae alba in human skin: Comparison with normal skin.

BACKGROUND: Striae distensae are common dermal lesions that progress through two different stages: the striae rubra, which appears to be erythematous, and striae alba, which is characterized by a hypopigmented feature. The clinical characteristics between striae distensae stages and normal skin remain unknown. OBJECTIVES: We aimed to investigate the clinical characteristics according to stages of striae distensae in terms of their biophysical properties, using objective noninvasive measurements in comparison with adjacent normal skin. METHODS: Sixty-one healthy female subjects with striae distensae were included as follows: 30 with striae rubra and 31 with striae alba on the abdomen and thighs. Hydration of the epidermis and dermis, skin color brightness, and Erythema index were measured. Skin elasticity, roughness, and dermal echo-density of the skin with striae distensae and adjacent normal skin were also measured. RESULTS: Hydration of the epidermis and dermis showed no significant difference between the skin with striae distensae and normal skin. Brightness of skin with striae alba and normal skin was significantly higher than that of skin with striae rubra. Erythema index of skin with striae rubra was significantly higher than that of skin with striae alba and normal skin. Skin with striae rubra and striae alba had a rougher surface than normal skin. Elasticity and dermal echo-density were significantly lower in striae distensae skin. CONCLUSIONS: Striae rubra and striae alba had similar biophysical properties in terms of skin hydration, elasticity, roughness, and dermal density. Moreover, striae distensae have less elasticity, more roughness, and lower dermal density than normal skin.

Phosphodiesterase 4B plays a role in benzophenone-3-induced phototoxicity in normal human keratinocytes.

Benzophenone-3 (BP-3), which is extensively used in organic sunscreen, has phototoxic potential in human skin. Phosphodiesterase 4B (PDE4B) has a well-established role in inflammatory responses in immune cells. Currently, it is unknown if PDE4B is associated with BP-3-induced phototoxicity in normal human keratinocytes (NHKs). We found that BP-3 significantly increased PDE4B expression in ultraviolet B (UVB)-irradiated NHKs. Notably, BP-8, a sunscreen agent that shares the 2-hydroxy-4-methoxyphenyl methanone moiety with BP-3, also upregulated PDE4B expression in NHKs. Upon UVB irradiation, BP-3 upregulated the expression of pro-inflammatory factors, such as prostaglandin endoperoxide synthase 2, tumor necrosis factor α, interleukin 8, and S100A7, and downregulated the level of cornified envelope associated proteins, which are important in the development of the epidermal permeability barrier. The additive effects of UVB-activated BP-3 on the expression of both pro-inflammatory mediators and cornified envelope associated proteins were antagonized by treatment with the PDE4 inhibitor rolipram. The BP-3 and UVB co-stimulation-induced PDE4B upregulation and its association with the upregulation of pro-inflammatory mediators and the downregulation of epidermal differentiation markers were confirmed in a reconstituted three dimensional human epidermis model. Therefore, PDE4B has a role in the mechanism of BP-3-induced phototoxicity.

Assessment of exposure for baby cosmetic care products in a Korean population.

Assessment of exposure to cosmetic products via the skin is important for evaluating the risks associated with the use of these products. However, few exposure studies have been conducted with babies, particularly in Asia. The aim of our study was to assess the exposure to selected cosmetic products in babies under the age of 36 months, over both winter and summer months. We evaluated exposure for seven cosmetic baby care products identified in a previous web-based survey as being commonly used by Korean parents. Parents were instructed to use their baby's products as per their usual habit, recording usage for each product on a daily basis over a 14-day period. Products were weighed at the start and completion of the study, with the change in weight used to determine the total amount of product used. Descriptive statistics for daily exposure were calculated. In this study, daily exposure for different products was influenced by sex, age groups and seasons. Of specific note, 3.51% of the lotion in a wet wipe was transferred to the skin. In conclusion, we provide baseline exposure data for baby products, with exposure being based on parents' usual use of the products.

Efficacy of fermented green tea on peripheral skin temperature: a randomized and placebo-controlled clinical study.

BACKGROUND: This study was aimed at assessing the therapeutic efficacy of green tea on peripheral skin for cold hypersensitive subjects, who had the feeling of cold hands and feet at cold temperatures, one of the most common complaints in Asian women. METHODS: This randomized and placebo-controlled clinical study included 60 female Korean subjects who had the feeling of cold hands and feet at cold temperatures. The subjects were randomly assigned into two groups to receive fermented green tea or a placebo (hot water). RESULTS: The skin temperature of the hands and feet was measured using digital infrared thermography at the baseline and at 15, 30, 45, and 60 min after the oral administration of the tea or placebo. The skin temperature of the hands and feet of the fermented green tea-administered group was significantly higher than that of the placebo-administered group. The temperature difference between the finger and the dorsum of the hand was significantly lower in the fermented green tea-administered group than that in the placebo group. CONCLUSIONS: Fermented green tea is helpful for cold hypersensitivity. This is the first clinical study to evaluate the efficacy of fermented green tea on peripheral skin in subjects having the feeling of cold hands and feet at cold temperatures by infrared thermography. However, further studies are necessary to evaluate the long-term effects of the fermented green tea for cold hypersensitivity and to elucidate the underlying physiological mechanism.

Comparison of skin color between two Asian populations: according to latitude and UV exposure.

BACKGROUND: Skin color varies among ethnic groups on accounts of genetic background. Within an ethnic group, skin color may also vary according to geographical environments and sun exposure habits. While many reports address skin color differences between ethnic groups, few have compared skin color within as ethnic group. AIMS: To compare skin color characteristics according to differences in latitude including UV exposure between two Asian populations (Korean and Cantonese [Chinese]). METHOD: We included 461 healthy female subjects: 317 Korean (age 42.3 ± 7.16) and 144 Cantonese (age 41.5 ± 11.2). Skin phototypes were classified according to the Fitzpatrick classification, and back skin color measured using the Minolta colorimeter. We evaluated the lightness (L*), yellowish (b*) value, individual typology angle (ITA°), and minimal erythema dose (MED). RESULTS: Fitzpatrick phototype ratios were similar in Korean (II: 19.9%, III: 78.9%) and Cantonese (II: 27.1%, III: 72.9%). However, the L* (68.47 ± 2.66 vs. 66.44 ± 2.47), ITA° (41.80 ± 5.51 vs. 40.20 ± 5.79), and b* (20.56 ± 1.71 vs. 19.28 ± 1.97) were significantly higher in Korean than in Cantonese. Korean had a significant lower MED than Cantonese (22.33 ± 2.89 vs. 23.38 ± 6.04). CONCLUSIONS: Subjective phototype self-assessment showed similar results in Korean and Cantonese. However, objective skin color parameters differed between the two populations. Koreans, who live at a higher latitude and get relatively little sun exposure, have lighter skin color than the Cantonese and burn easily upon UV exposure.