How Much Beta Carotene To Change Skin Color

one.

Introduction

Carotenoids course an integral function of the human antioxidant defense network, which protects the body against cellular damage caused past the harmful actions of costless radicals.^{i – 3} Excessive amounts of free radicals can crusade oxidative stress, which has been linked to a multifariousness of negative health consequences.^{4 , v} Carotenoids potentially provide a protective effect confronting a variety of disorders linked to oxidative stress, including cardiovascular disease, certain cancers, and eye disorders,^{2 , 6 – 8} although two studies found an increased incidence of lung cancer subsequently beta-carotene supplementation in heavy smokers and individuals exposed to asbestos.^{ix , ten} A protective effect is also consequent with the findings that depression carotenoid levels were associated with increased all-cause mortality in a large study of U.S. adults.¹¹ Carotenoids cannot be synthesized by the human being body and are obtained from the diet, primarily from red, orange, or yellow pigmented fruit and vegetables.^{2 , 12} Plasma carotenoids are deposited in various human tissues, including the liver, adipose tissue, and skin.^{13 , 14}

Carotenoids accumulate in man skin by either diffusing from the blood, through the hypodermis and dermis to the epidermis, or transportation to the epidermis via sweat, which contains carotenoids.^{xiv , xv} The 2 nearly prominent carotenoids in the peel are beta-carotene and lycopene.^xiv Studies have shown that ultraviolet radiations¹⁶ and infrared radiation¹⁷ reduce the concentration of carotenoids in the skin, presumably because the carotenoids are destroyed through their interaction with radiations-induced costless radicals. Oxidative stress is associated with enhanced skin aging,^xviii and conversely, pare with a high carotenoid concentration appears younger¹⁴ and has fewer furrows and wrinkles than skin with a low carotenoid concentration.¹⁹ Supplementation with beta-carotene (and increased dietary intake of fruit and vegetables) besides produces an increase in the normal skin yellowness^{20 – 22}—only not skin redness or luminance²¹—of Caucasian skin, and studies have shown that a somewhat yellower skin color is considered healthier and more than attractive by both African and Caucasian observers.^{20 , 23 – 25}

Skin carotenoid concentrations are highly correlated with serum carotenoid concentrations^{26 – 28} and tin, therefore, provide a noninvasive index of systemic carotenoid concentrations. Skin carotenoid concentrations can besides serve equally biomarkers for fruit and vegetable consumption,^{20 – 22 , 29} the antioxidative capacity of human skin, oxidative stress, in general,^{30 , 31} and possibly vitamin A levels [since beta-carotene is a precursor of vitamin A (Ref. 32)]. Another advantage of investigating skin carotenoid concentrations is their utilize in appearance-based interventions.²² Whitehead et al.³³ found that participants reported a significant, sustained increase in their fruit and vegetable consumption after researchers demonstrated the benign issue of fruit and vegetable consumption in a digital manipulation of the participant's own facial image. Participants who received health information and those who saw the same digital manipulation in a generic face up did not report a significant increment in fruit and vegetable consumption.³³

Very little is known virtually the influence of carotenoid supplementation on African pare. First, although various studies have shown an increase in skin carotenoid concentration and skin yellowness due to carotenoid supplementation in Caucasian skin,^{20 , 21 , 27 , 28 , 34} to our noesis, no study has all the same examined the result of carotenoid supplementation on African skin. Second, we previously found that African observers significantly increased skin yellowness (and lightness) in same race facial images to increment the facial images' apparent health.²⁰ It is, however, even so unclear whether moderate increases in carotenoid concentrations produce perceivable xanthous colour differences in African peel, especially under natural sunlight conditions.

To accost these gaps in the literature, this study aims to test whether beta-carotene supplementation produces a significant carotenoid-specific color modify in three unlike regions of African skin: lightly pigmented skin, highly pigmented skin with depression sun exposure, and highly pigmented pare with high sunday exposure.

2.

Materials and Methods

2.one.

Ethical Approval

This written report was approved in writing past the Ideals Commission at the University of Pretoria (EC110630-050). All participants gave written informed consent prior to taking function in the study.

2.ii.

Participants and Written report Design

Ten black African female person participants ( $\text{mean age}=27.57$ ; $\mathrm{s}.\mathrm{d}.=\mathrm{half-dozen.85}$ ) were recruited from the University of Pretoria. Participants completed a questionnaire containing questions on their age, gender, ethnicity, and the use of skin lightening products. All participants reported beingness of African descent and none of the participants reported using skin lightening products. The questionnaire also contained questions concerning contraindications for beta-carotene supplementation: pregnancy or breastfeeding; allergy to basics, soya, and sulfites; or heavy smoking. Co-ordinate to the Globe Health Organisation definition, a heavy smoker smokes more than 20 cigarettes daily.³⁵ As a conservative cutoff, we, therefore, excluded anyone who smokes more than ten cigarettes daily. Ane participant was allergic to basics and was, therefore, excluded from the study.

Using a Konica Minolta CM2600d reflectance spectrophotometer, we measured half-dozen predefined pare areas in three dissimilar regions of African skin: palm (lightly pigmented skin); inner arm (highly pigmented peel with low sunday exposure); outer arm, forehead, left cheek, and correct cheek (highly pigmented skin with high sun exposure). The predefined skin areas were measured in (1) CIELab colour space, CIELab L* (luminance centrality), CIELab a* (green-red axis), CIELab b*(blue-xanthous axis), and (2) spectral reflectance values (400 to 740 nm). The measurement discontinuity was held lightly against the skin to minimize force per unit area-induced bleaching. All participants were asked to remove their makeup using hypoallergenic wipes at least fifteen min before spectrophotometry measurements.

The supplementation report was conducted between August and early October 2011 (winter/early on spring). Participants were provided with a calendar week's supply of Holland & Barrett beta-carotene capsules [15 mg; containing soya bean oil, capsule shell (gelatine, glycerine), corn oil, thickener (yellow beeswax), beta-carotene, emulsifier (soya lecithin), vitamin E (as dl-Alpha tocopherol)] and asked to take one capsule daily and return on a weekly ground for 8 weeks. Each week nosotros measured the six predefined skin areas with the spectrophotometer and participants were provided with another week'south supply of beta-carotene supplements. Two participants discontinued the report in week five because they were experiencing symptoms that they thought might be attributed to beta-carotene supplementation (participant i: facial rash; participant 2: nervous and silly), leaving seven participants for the final analysis.

2.three.

Statistical Assay

We performed a repeated measures general linear model (GLM), with measurement area (forehead, left cheek, right cheek, inner arm, outer arm, and palm) and week (weeks 0 to viii) as within-field of study factors. Next, separate repeated measures GLMs were performed for each measurement area to determine which measurement areas showed significant increases in skin yellowness. To control for multiple testing, we adapted the blastoff level to a conservative $\alpha =0.005$ using Bonferroni correction ( $0.05/10$ ). The difference in spectral reflectance values earlier and subsequently supplementation were used to verify whether the change in CIELab b* values was most likely due to carotenoids. All analyses were performed in SPSS version 21.

iii.

Results

3.one.

Descriptive Statistics

A descriptive table with CIELab b*, CIELab L*, and CIELab a* values before and after supplementation are provided in Table one.

Table 1

Mean CIELab b*, CIELab L*, and CIELab a* values at the unlike measurement areas before and after supplementation. Standard deviations are indicated in brackets.

	CIELab b*			CIELab Fifty*			CIELab a*
	Before	After	Change	Before	Later on	Change	Before	Later on	Alter
Palm	17.66 (1.58)	19.33 (2.41)	ane.67	58.30 (one.88)	58.30 (0.95)	0.00	10.13 (1.40)	12.78 (1.49)	2.65
Inner arm	18.64 (i.55)	19.78 (1.72)	1.14	51.fifty (4.79)	49.98 (five.06)	$-1.52$	8.64 (0.76)	viii.99 (0.83)	0.35
Outer arm	18.xviii (3.00)	eighteen.42 (3.14)	0.24	45.23 (6.17)	43.83 (6.00)	$-\mathrm{1.forty}$	ten.53 (0.57)	x.54 (0.78)	0.01
Brow	17.49 (three.36)	17.16 (4.x)	$-0.33$	43.43 (5.27)	42.63 (5.28)	$-0.80$	11.91 (0.84)	11.67 (1.19)	$-0.24$
Left cheek	20.45 (one.40)	xx.01 (2.41)	$-0.44$	48.42 (iv.29)	47.22 (v.04)	$-1.20$	11.50 (0.77)	xi.41 (0.78)	$-0.09$
Correct cheek	xx.71 (2.00)	twenty.29 (2.21)	$-0.42$	48.26 (four.71)	47.17 (4.04)	$-\mathrm{ane.09}$	11.32 (0.66)	eleven.46 (0.86)	0.14

three.ii.

Repeated Measures GLM

Muachly's test indicated that the assumption of sphericity had been somewhat violated for measurement area [ ${\mathrm{x}}^{\mathrm{two}}(\mathrm{xiv})=25.84$ , $p=0.049$ ); therefore, degrees of freedom were corrected using Greenhouse–Geisser estimates of sphericity ( $\epsilon =0.42$ ). The repeated measures GLM analysis of CIELab b* revealed a significant principal effect of measurement area [ $\mathrm{F}(2,\mathrm{thirty})=5.530$ , $p=0.018$ , $\eta p_{\text{partial}}^2=0.480$ , $\text{observed power}=0.768$ ] and calendar week [ $\mathrm{F}(8,48)=2.375$ , $\mathrm{p}=0.031$ , $\eta p_{\text{fractional}}^{\mathrm{two}}=0.284$ , $\text{observed power}=0.836$ ]. There was likewise a significant interaction between week and measurement expanse [ $\mathrm{F}(\mathrm{40,240})=2.235$ , $p\le 0.001$ , $\eta p_{\text{fractional}}^{\mathrm{ii}}=0.271$ , $\text{observed ability}=\mathrm{i.000}$ ]. These results indicate that in that location was a difference in skin yellowness between the dissimilar measurement areas (Fig. 1). More importantly, results evidence that there was an increase in participants' peel yellowness over the 8-calendar week supplementation study (CIELab b* earlier: $\text{hateful}=\mathrm{xviii.856}$ , $\mathrm{s}.\mathrm{d}.=1.807$ ; CIELab b* after: $\text{mean}=\mathrm{nineteen.165}$ , $\mathrm{s}.\mathrm{d}.=2.418$ ), with certain measurement areas showing a larger modify in CIELab b* than others (Fig. 1). The interaction between week and measurement area (just neither of the master effects) was nonetheless pregnant at the conservative Bonferroni adjusted level of $\alpha =0.005$ .

Fig. 1

The change in skin yellowness (CIELab b* values) over the 8-calendar week supplementation study for unlike measurement areas. The palm (solid square) and the inner arm (solid triangle) were the simply two measurement areas that showed a significant increase in CIELab b* values.

Carve up repeated measures GLMs for each measurement area were used to determine which measurement areas showed significant increases in skin yellowness. When analyzed separately, simply the palm [ $\mathrm{F}(8,48)=\mathrm{four.324}$ , $p=0.001$ , $\eta p_{\text{partial}}^{\mathrm{ii}}=0.419$ , $\text{observed ability}=0.988$ ] and inner arm [ $\mathrm{F}(\mathrm{eight},48)=3.002$ , $p=0.008$ , $\eta p_{\text{partial}}^{\mathrm{two}}=0.333$ , $\text{observed}\text{power}=0.923$ ] measurement areas showed a significant increase in pare yellowness over the 8-week supplementation written report (all other measurement areas $p\ge 0.11$ ; Fig. 1). The CIELab b* increase in the palm remained significant at Bonferroni adjusted blastoff, but the CIELab b* increase in the inner arm did not. Since CIELab a* (skin redness) values in the palm of the hand also increased substantially after supplementation (Table one) and since basal CIELab b* and CIELab a* are highly correlated in the palm of African skin ( ${\mathrm{r}}_{\mathrm{southward}}=0.786$ , $p=0.036$ ), we performed a repeated measures GLM of CIELAb a* in the palm of the hand to compare the variance explained past CIELab b* and CIELab a*. The palm measurement area also showed a significant increase in skin redness over the 8-calendar week supplementation study [ $\mathrm{F}(8,48)=3.419$ , $p=0.003$ , $\eta p_{\text{fractional}}^{\mathrm{two}}=0.363$ , $\text{observed power}=0.956$ ], but CIELab a* explained less variance than CIELAb b* ( $\eta p_{\text{partial}}^{\mathrm{two}}=0.419$ ), indicating that CIELab b* is driving the association between beta-carotene supplementation and peel colour change.

3.iii.

Change in Spectral Reflectance due to Dietary Supplementation of Beta-Carotene

To verify whether the change in CIELab b* was probable to be due to a change in carotenoid coloration, we calculated the change in spectral reflectance values across the supplementation study for the palm and inner arm (week 8 to calendar week 0). The differences were and then averaged across all participants for each position (Fig. two). Lower values betoken that a smaller proportion of incident light is reflected (which is consistent with a greater light adsorption past peel pigments). Based on the literature, we expected a decrease in spectral reflectance values at 450 to 490 nm—the wavelengths associated with superlative light absorption by beta-carotene^{20 , 36}—if peel carotenoid coloration increased across the supplementation written report. Equally expected, nosotros observed a decrease in spectral reflectance values at $\sim 450$ to 490 nm (especially for palm measurements), indicating that the change in CIELab b* values were probable to be due to a modify in carotenoid coloration (Fig. 2).

Fig. two

Alter in spectral reflectance values due to dietary supplementation of beta-carotene. The graph shows a trough at $\sim 450$ to 490 nm for both measurements (specially the palm), which is consistent with an increment in light adsorption by skin carotenoid paint.

iv.

Discussion

The aim of this report was to determine whether beta-carotene supplementation produces a meaning yellowish color change in different regions of African skin. To our noesis, this is the kickoff study to exam the effect of carotenoid supplementation in African skin. Our results testify that oral supplementation with a daily dose of 15 mg beta-carotene over the course of 8 weeks was associated with a significant increase in peel yellowness in African skin, primarily in lightly pigmented peel (east.grand., palm), but also to some extend in highly pigmented skin with low sun exposure (e.chiliad., inner arm). Consistent with previous findings in Caucasian skin,^twenty beta-carotene supplementation was most strongly associated with CIELab b* skin colour changes in the palm measurement area (explaining 42% of the variance). CIELab a* values also increased significantly in the palm measurement area beyond the supplementation study. This is not unexpected, given the loftier correlation between CIELab b* and CIELab a* values in African peel.^{24 , 25} Our results show that CIELab b* is, however, driving the association between beta-carotene supplementation and skin colour modify. Palm measurements of CIELab b* levels might, therefore, serve as a potential marker for systemic carotenoid concentrations;^{26 , 27} fruit and vegetable consumption;^{20 – 22 , 29} the antioxidative chapters of human skin; oxidative stress, in general;^{thirty , 31} and possibly vitamin A levels in the African population [since beta-carotene is a precursor of vitamin A (Ref. 32)].

We should signal out some limitations to the study. First, the study had a adequately low sample size. Nevertheless, repeated measures essentially increase the power of the analysis (due east.g., Ref. 37), and mail service hoc power analyses indicate that the study had sufficient power ( $\text{observed power}>0.8$ ) to detect a beta-carotene supplementation effect on skin coloration. Second, we did not include a washout menses before and later the supplementation study, which might have increased the noise in beta-carotene levels. Tertiary, we did not measure out plasma carotenoid levels directly. Information technology is, withal, highly likely that the plasma carotenoid levels increased after supplementation, given that we observed a significant increment in carotenoid-specific coloration in the palm of the hand after beta-carotene supplementation. Still, future studies could do good from including plasma carotenoid levels, washout periods, and a larger sample of male and female participants.

We did non find a significant increase in skin yellowness in highly pigmented peel that has high lord's day exposure (e.g., outer arm and face). This is nigh likely because an increase in melanin pigmentation due to increased lord's day exposure in early jump—as evidenced by decreased CIELab 50* values (Table 1)—overshadowed the changes in carotenoid pigmentation. Some other nonmutually exclusive explanation is that carotenoids accumulated during the supplementation study may have been oxidized through increased ultraviolet and infrared exposure during early jump. It is, therefore, unlikely that participants volition be able to observe a beneficial issue of fruit and vegetable consumption in sun-exposed highly pigmented African skin under natural sunlight weather. Of course, a change in carotenoid coloration might as well be observable in lord's day-exposed highly pigmented African skin during late summertime/early winter or if participants eat more than fruit and vegetables or higher doses of carotenoid supplementation.

In summary, nosotros found a significant increase in skin yellowness of African skin afterward an 8-week beta-carotene supplementation written report, merely but in lightly pigmented skin (e.1000., palm) and to some extend in highly pigmented skin with low sunday exposure (due east.g., inner arm). Pare carotenoid measurements in the palm of the mitt or lord's day-protected pare areas might, therefore, serve as a potential marking for systemic carotenoid concentrations in people of African descent.

Acknowledgments

The authors were funded by the Due south African National Research Foundation (5.C.), the British Academy, and Wolfson Foundation (D.P.).

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Biography

Vinet Coetzee obtained her PhD in 2011 from the University of St. Andrews, Scotland. She completed a two-year NRF Deficient Skills postdoctoral fellowship and is currently employed as a research swain at the Section of Genetics, University of Pretoria, South Africa. Her principal enquiry involvement lies within the interdisciplinary field of human being evolutionary biology. More specifically, her work focuses on morphological cues that indicate wellness. She has published 19 papers in peer-reviewed journals.

David Ian Perrett is a professor in psychology at the Academy of St. Andrews, Scotland. He received his D.Phil. from the Academy of Oxford in 1981. His research focuses mainly on face perception, including facial cues to health. He received the British Psychological Society President'southward Award, the Golden Brain Award, the Experimental Psychology Order Mid-Career prize, and a British Academy Wolfson Research Professorship. He has published over 200 papers in peer-reviewed journals.

Source: https://www.spiedigitallibrary.org/journals/journal-of-biomedical-optics/volume-19/issue-02/025004/Effect-of-beta-carotene-supplementation-on-African-skin/10.1117/1.JBO.19.2.025004.full

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