Diet and Aesthetics

The purpose of this 2018 study was to find out whether the consumption of specific fruits or vegetables is connected to skin yellowness in young women. While carotenoids found in fruits and vegetables are known to contribute to skin yellowness, it was hypothesized that eating increased amounts of fruits and vegetables that are rich in these pigments (especially β-carotene) would induce the greatest variation in skin yellowness. Based on the food questionnaires completed and skin assessments conducted on women from the Hunter region, NSW, Australia, it was demonstrated that the higher combined consumption of fruits and vegetables, as well as higher total fruit intake, were associated with increased skin yellowness. A significant proportion of the variation seen in skin yellowness was attributed to the following fruits and vegetables: apples/pears, dried fruits, mangos/pawpaws, beans/lentils, spinach, broccoli, corn, and baked beans. This study supports the notion that the consumption of these 8 fruits and vegetables may confer a desirable effect on appearance by increasing skin yellowness. In addition, total combined fruit and vegetable intake appeared to have the same impact on skin.

This 2012 article focused on the effects of fruit and vegetable consumption on skin-color since increased skin yellowness associated with the intake of dietary carotenoids are said to enhance human appearance and serve as a cue for sexual selection in other species. Whitehead et al. planned to determine the magnitude and duration of diet change required to alter perception of skin color. The 35 participants were without make-up, self-tanning agents, and had not been exposed to intense UV light. Their diet and skin color were recorded at baseline, and after 3 and 6 weeks. The overall modification in fruit and vegetable consumption in the 6 weeks correlated with changes in skin redness and yellowness over this period. Altered reflectance in diet-linked skin was significantly linked with spectral absorption of carotenoids but not of melanin. It was also discovered that diet needed to be altered by 2.91 portions per day to make the women look healthier, while 3.3 portions were said to be required for increased attractiveness. In conclusion, elevated fruit and vegetable consumption positively influenced Caucasian skin appearance within six weeks.

Although eating more fruits and vegetables has been associated with enhancing facial attractiveness, Appleton et al. (2018) state that there is yet to be a study on the causal link between fruit and vegetable consumption and perceived attractiveness. This present study therefore analyzed people’s perceptions on attractiveness before and after the intake of 2, 5, or 8 portions of fruits and vegetables per day for 4 weeks. The 30 participants who reported low fruit and vegetable consumption at baseline were photographed before and after the 4-week intervention. These pictures were rated by 73 independent individuals for facial attractiveness, facial skin yellowness, redness, healthiness, clarity, and symmetry. Although 4 weeks of the fruit and vegetable intervention did not appear to directly affect attractiveness ratings, there was some evidence to support an indirect effect on skin yellowness among females. Again, no correlation was found between fruit and vegetable intake and skin healthiness, but skin healthiness showed a connection to facial attractiveness. The researchers conclude that the increased dietary inclusion of fruits and vegetables for 4 weeks indirectly increased female attractiveness through enhanced skin yellowness. However, due to the small effect size observed, using facial attractiveness to convince people to eat more fruits and vegetables is not necessarily recommended.

This 2019 article originally published in French has been translated to inform us of the benefits and risks of eating fruits and vegetables. Amiot-Carlin presents evidence from epidemiological studies that have demonstrated the protective roles of fruits and vegetables in cardiovascular disease, and have suggested its promising effects on weight gain, diabetes, colorectal cancer, and specific forms of breast cancer. The risk of developing cardiovascular disease is reduced by eating up to 800g of fruits and vegetables a day, while up to 600g/day appears to be sufficient to protect oneself from certain forms of cancer. To consume a balanced diet, it is important to eat enough fruits and vegetables, raw and cooked, while restricting the amount of ultra-processed and sweet products. There are many components of fruits and vegetables that offer protection, such as fibres, vitamins -B9, C-, minerals, polyphenols, carotenoids and sulphur compounds. White fruits, green leafy vegetables, and fruits and vegetables particularly high in beta-carotene and vitamin C have all shown protection from cardiovascular disease. Furthermore, cruciferous, and green-yellow vegetables appear to reduce incidence of some cancers.

Since piceatannol has been found to have a range of positive effects on skin (promoting collagen production and removing reactive oxygen species), this 2018 double-blind trial assessed the impact of piceatannol-rich passion fruit seed extract on the skin of healthy Japanese women aged 35-54 years. The study involved the random allocation of 32 women with dry skin to either receive the passion fruit seed extract (containing 5mg of piceatannol) or a placebo (dextrin) for 8 weeks. Questionnaire interviews were held at baseline, and after 4 and 8 weeks. The consumption of the passion fruit seed extract led to significant increases in skin moisture after 4 and 8 weeks (compared with before the trial). Transepidermal water loss reduced over time, although the differences were not significant. The questionnaires also revealed significantly less “perspiration” and “fatigue” observed in the passion fruit seed extract (piceatannol) group, relative to the placebo group. The overall data indicates that consumption of passion fruit seed extract (containing high quantities of piceatannol) may enhance the moisture of dry skin and reduce fatigue in women.

As many people are on the search for naturally occurring botanicals that prevent photoaging (premature aging of the skin caused by repeated exposure to UV light), Maruki-Uchida et al. (2013) highlight piceatannol and one of its dimers, scirpusin B, as antioxidants with high potential. Piceatannol and scirpusin B, which are present in passion fruit seeds, were investigated alongside passion fruit seed extract on their effects on keratinocytes (skin cells making up most of the uppermost layer of the skin). The experiment proved that piceatannol is an active component of the passion fruit seed extract in keratinocytes. In addition, the pretreatment with piceatannol reduced the production of reactive oxygen species induced by UV-B light in the keratinocytes. Piceatannol was also found to lower the activity of matrix-metalloproteinase (MMP)-1 activity, which are normally enhanced by UV-B light. To summarize these results, piceatannol and passion fruit seed extract (which contain high amounts of piceatannol) are both potential anti-photoaging cosmetic ingredients.

Vostálová et al. (2019) write about Silybum marianum, a medicinal plant traditionally used in treatment of liver disorders, and an extract of its seed named silymarin, which has more recently been studied for its use in dermatology. While the UVB-protective properties of silymarin have been studied, one limited area of research is its influence on activity of enzymes involved in the photoaging process. The objective of this present study was to evaluate silymarin and its flavonolignans on their potential to inhibit the enzymes collagenase, elastase, and hyaluronidase. DHSB, one of the flavonolignans, showed the greatest ability to scavenge DPPH radical, and appeared to be the best protector from UV-A. Silymarin and all of the flavonolignans investigated were found to inhibit collagenase and elastase activity but not anti-hyaluronidase. DHSB was the most potent of the flavonolignans. Overall, the results suggest that silymarin and its flavonolignans are promising agents for slowing down the progress of skin aging, and for skin protection against the damaging effects of solar radiation.

In this 2018 study, McGuirt et al. surveyed supermarket goers and objectively assessed them on their fruit and vegetable consumption through skin carotenoid evaluation. In addition to using the National Cancer Institute Fruit and Vegetable screener to calculate daily servings of fruits and vegetables, the researchers used a reflection spectroscopy measure called “Veggie Meter” to objectively ascertain the shoppers’ fruit and vegetable intakes. Accessibility to the supermarket was also analyzed and the shoppers were asked how frequently they visit the supermarket. The goal of this study was to determine the relationship between accessibility to that specific supermarket where the survey took place (according to the respondents), and their intake levels of fruits and vegetables. There was a positive correlation between skin carotenoids and scores for one of the accessibility assessments (mRFEI) and for the Special Supplemental Nutrition Program for Women Infants and Children (WIC). This links healthier food environments and participation in the WIC with fruit and vegetable consumption (via skin carotenoids).

The aim of this 2019 study was to analyze the impact of consuming lingonberry and amla fruit extract on human skin. Ninety-nine healthy female participants were randomized to either receive a drink containing 25 mg of lingonberry extract and 30 mg of amla fruit extract, a drink with 50mg of lingonberry extract and 60mg of amla fruit extract, or a placebo drink. While each person consumed 50ml of the assigned drink every day for 12 weeks, neither the subjects nor the experimenters were informed of the exact drink allocation. After 12 weeks of lingonberry and amla fruit extract intake, significant improvements were seen in skin elasticity, skin thickness, stratum corneum water content, and the degree of wrinkles (around the eyes), all in a dose-dependent manner. It was concluded that lingonberry and amla fruit extract prevents the weakening of skin and may hold potential as an anti-aging agent.

This 2012 review focuses on carotenoid coloration and how it may be a sexually selected cue to condition in species that possess elaborate color vision. Whitehead et al. emphasize the fact that for humans, this skin carotenoid pigmentation stimulated by fruit and vegetable consumption may provide a similar cue to health, especially in light-skinned Asians and Caucasians. There is evidence indicating that skin coloration improves apparent health, and that modifying diet can affect people’s perceptions of skin color within weeks. In fact, the benefits that the skin coloration associated with increased fruit and vegetable consumption provide to apparent health is greater than that of melanin pigmentation. Lastly, the authors highlight the positive impacts of diet enhancement on appearance, presenting a strong argument for adopting a healthy lifestyle.

Since more people will be inclined to change their dietary behavior if it was confirmed that diet enhancement would positively influence their looks or appearance, the aim of this 2015 review was to examine the literature on appearance’s relationship with dietary intake and determine to what extent dietary interventions affect perceived/actual appearance. Pezdirc et al. firstly systematically searched several databases for studies involving adult participants (18+ years old) that assessed appearance-related outcomes, and either observed or altered subjects’ dietary consumptions from actual food or supplement use. Of the 27 studies gathered for analysis, 19 were deemed as being of “positive” quality. According to the observational studies, numerous aspects of dietary intake were associated with skin coloration and aging. Most of the studies checked dietary supplements’ effects on skin appearance among women, while only one study looked at the impact of actual food consumption on appearance. Supplementation did result in significant improvements in at least one actual or perceived appearance-related outcome (facial wrinkling, skin elasticity, roughness, and skin color). This review highlights the need for additional studies of high quality that evaluate the effect of actual food intake on appearance using validated tools.

This 2017 review discusses the potential roles of vitamin C in skin health while examining the latest research studies. Pullar et al. explain that vitamin C is normally abundant in the skin, but its involvement in many important functions including stimulating collagen production and protecting the skin from photodamage caused by UV radiation are the justifications for the addition of vitamin C to some topical applications. But it is not clear whether applying these treatments directly to the skin is more effective than obtaining vitamin C through the diet. This review attempts to compare these 2 methods of vitamin C administration, flagging the areas of research that are limiting our understanding of vitamin C’s potential benefits on skin health. Finally, this article also suggests which skin properties are most likely to be enhanced by vitamin C consumption.

This 2020 review discusses the structure of skin, the signs of skin aging, and the possible mechanisms behind this aging process. Many people are fascinated about ways to maintain healthy skin and delay aging. Cao et al. explain that skin aging is a complex biological process characterized as chronological aging (referring to total length of time a person has been alive) and photo-aging (premature aging due to repeated exposure to ultraviolet radiation). Thanks to modern medicine, human life is increasingly being prolonged. However, environmental conditions are deteriorating, which can influence skin aging too. It is therefore that safe and effective methods are found to treat skin aging. Diet’s important relationship with skin has gradually become recognized. This present review demonstrates which stage we are at with regards to research, and discusses the possible directions of diet management, the effect of foodborne antioxidants on skin aging, and the challenges in this area of research that need to be addressed.