Nutraceuticals and food-based cosmetics are a growing field in dermatology. Almonds are a commonly studied food, as they are a rich source of fatty acids, phytochemical polyphenols and antioxidants such as vitamin E [1
]. A previous randomized 16-week pilot study that compared almond ingestion to a calorie-matched intervention showed, with statistical significance, that almond supplementation improved wrinkle severity in postmenopausal women with Fitzpatrick skin types I and II, relative to control [2
Postmenopausal women are more susceptible to the development of facial-aging related changes [3
]. Skin aging is a multifactorial process and there is growing evidence that nutrition levels and eating habits can contribute to morphological changes in the skin and modulate oxidative stress and inflammation [5
]. In the case of almonds, the vitamin E (alpha-tocopherol) content can range between 21.9–31mg/100g of almonds [6
] and it has been shown that almond consumption can elevate circulating alpha-tocopherols [7
]. Additionally, previous studies have shown that the ingestion of alpha-tocopherol-containing supplements can improve facial wrinkles in post-menopausal women [9
]. Alpha-tocopherol has antioxidant and photoprotective functions, especially against ultraviolet type A radiation that is implicated in the development of wrinkles and pigment unevenness [11
]. Furthermore, tocopherol has pigment reducing and skin brightening properties [12
The Fitzpatrick scale is a classification system that ranges from I–VI and was developed to estimate the response to ultraviolet exposure with varying skin pigmentation [14
]. The type I classification refers to skin that always burns and never tans, while the type II classification refers to skin that burns frequently and tans with difficulty [14
]. In addition to estimating the response to ultraviolet light, some research suggests that in middle-aged subjects, Fitzpatrick skin types may be influential in skin aging, where skin types I and II may experience photoaging at an accelerated pace [15
]. Fitzpatrick types I and II were the population of interest in the pilot study, and the population assessed in this investigation.
This study expanded upon the previous pilot study to both expand the number of participants and to increase the assessment follow up from 16 weeks to 24 weeks. We assessed the influence of almond consumption on wrinkle severity, skin pigmentation and other skin biophysical properties.
This randomized clinical trial demonstrates a significant reduction in wrinkle severity in the intervention group consuming almonds. In fact, this study showed an increased magnitude of reduction in wrinkle severity of 15% at 16 weeks, compared to the previous pilot study assessing the same outcome, which showed 9% reduction at 16 weeks compared to baseline [2
]. Furthermore, this study showed a continued reduction of that magnitude at 24 weeks. Surprisingly, there was also a reduction in the overall pigment intensity in the almond supplementation group.
The antioxidant and photoprotective properties from alpha-tocopherols in almonds may serve to reduce development of wrinkles and pigment unevenness [11
]. This may further account for the results in the reduction of skin pigmentation in the almond group. Vitamin E’s effects on pigmentation has been documented in the literature, especially by interacting with lipid peroxidation of melanocyte membranes, increasing glutathione content and inhibiting tyrosinase, a key enzyme in pigmentation [17
]. Interestingly, vitamin E was found to have minimal efficacy in treating pigmented disease such as chloasma [18
]; however, when used in combination with other vitamins, such as A and C, vitamin E showed an improvement in skin pigmentation [18
]. Interestingly, almonds are not just a rich source of vitamin E but also a source of niacin, which has been shown to improve facial pigmentation. Our findings emphasize the need to look at almonds as a whole food with multiple nutrient components rather than oversimplifying its nutritional content to its tocopherol content.
This study confirmed the findings of a previous almond pilot study in regards to the TEWL and sebum excretion results [2
], except that the control group had a large increase in their sebum excretion rate. Our findings suggest that the caloric intake may not be the driving factor in sebum excretion rate. The food supplementation in the control group added extra sugars to the diet compared to the almond supplementation group and may explain why the sebum excretion rate was increased in the control supplementation group, although this would require further specific study. Although previous research has demonstrated that sebum excretion has a negative association with wrinkle severity [20
], our data suggests that sebum excretion rate may be more nuanced based on the foods that are ingested and that the role of the sugar content in the foods may influence wrinkles, as was suggested in a previous prospective study with high mango intake compared to low mango intake [21
The influence of whole foods on skin health and appearance continues to be a growing field. Recently, a study assessed the influence of mangos on wrinkles and skin pigmentation [21
]. Specifically, Fam et. al. found an increase in erythema of the cheeks with 85 g of mango intake (p
= 0.04), reduction of wrinkles with 85 g of mangos and the opposite effects with a 250 g mango intake in postmenopausal women with Fitzpatrick skin types II or III. It is thought that ß-carotene and other carotenoids provide photoprotection of the skin through antioxidant effects [21
]. Therefore, it is unlikely that erythema was caused by the amount of β-carotene consumed from the fruit. Furthermore, β-carotene has been shown to decrease erythema in other studies [22
Consistent results of the reduction of wrinkles due to almonds in this and the previous pilot study suggest that diet can influence markers of facial photoaging. In addition to basic sun protection habits, such as regular use of mineral-based sunscreens and sun protective clothing, almonds and their components may have a part in the reduction of skin wrinkles and pigment intensity. Our unexpected findings of reduced pigment intensity suggest that future studies should include higher Fitzpatrick skin types and younger participants to further assess the role of almond supplementation on facial pigment.
This study was limited to 24 weeks and our results do not give insight into longer durations of ingestion. This study was limited to postmenopausal woman with sun sensitive Fitzpatrick skin types I and II and the results cannot be generalized to younger, male, or higher Fitzpatrick skin type populations. In addition, the supplementation between the almond vs. the control group was not macronutrient matched, though it was calorically matched.