Danielle Selden- Vitamin A Critique Paper
Vitamin A’s ability to protect cells from oxidation, regulation of gene expression, and aid
in cell differentiation makes Vitamin A an important nutrient in regards to photoaging and the
prevention of wrinkles. The study, “Differential effects of low-dose and high-dose betacarotene supplementation on the signs of photoaging and type I procollagen gene expression in
human skin in vivo” considers the role of the pro-vitamin A molecule beta-carotene. The authors
Soyun Cho, at el. deliver promising findings regarding low-dose supplementation of betacarotene in the prevention and repair of photoaging (1).
The purpose of this article is to look at the effects of two different doses of beta-carotene
given over the course of 90 days to determine the antioxidant or pro-oxidant properties of betacarotene in photoaging skin. Interestingly, past clinical studies have yet to find a consensus that
beta-carotene provides protection as an antioxidant against UV radiation, and other studies have
shown beta-carotene to express a pro-oxidant quality. This disagreement in the effects of dietary
beta-carotene sparked the author’s interests to complete this study. Researchers Cho at el.
measured wrinkles and elasticity, procollagen gene expression (production and degradation) and
ultraviolet (UV)-induced damage in the skin (assessing visual changes). This study is
meaningful for the beauty and supplement industry, while many researchers and cosmetic
companies are looking for constitutes that can slow cutaneous aging (1). Results such as these
listed in this article can pave the way for further research on the benefits of the pro-vitamin betacarotene and can promote consumer interest in purchasing products with these proven benefits.
Cho at el. took a simple approach in conducting this study. The methods included
recruiting 30 healthy women (29 completed the study), ages 49-68 years old, and randomizing
subjects into groups of two different doses of beta-carotene (low-dose or high-dose), during a 90
period. The low-dose group was given 30mg/day and the high-dose group was given 90mg/ day.
Exclusion criteria included: no use of topical corticosteroids or retinoids two weeks prior. One
month prior the women could not use systemic steroid, vitamin intake or phototherapy. In
addition, no smokers, no use of anti-wrinkle/ whitening cosmetics, topical retinoids, chemical
peels, vitamins, or any other food supplements (including Spirulina and Chlorella) during this
study.
The women were measured at baseline and completion, and baseline measurements were
used as the control group in the study. Facial wrinkles and elasticity were measured objectively
by clinical photographs of the face in the crow’s feet area using skin replica and visiometer SV
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Danielle Selden- Vitamin A Critique Paper
600. The visiometer is a computerized instrument that uses light transmission to look at the
surface of the skin, which has 5 roughness parameters; the R-values: R1-R5 decrease as wrinkles
diminish. Facial elasticity was measured also in the crow’s feet region with a non-invasive, in
vivo suction skin elasticity meter Cutometer MPA 580, that also uses R-values to measure
elasticity: the closer to R1 then the more elastic the skin is. The buttock skin was measured by
type 1 procollagen, martox metalloproteinase-1, fibrilin-1, mRNA levels and UV0induced
thymine dimer and 8-hydroxy-2’-deoxyguanosine formation. The phototherapy device, Philips
TL-20W/12 fluorescent lamps were used as the UV source, and skin was irradiated in a 1 x 1
cm-sized squares with 10mj/cm2 increments of UV doses. Some subjects agreed to do biopsies
within 24 hours, and those samples were sectioned and fixed in formalin overnight to stain. The
samples were further measured using an image analysis computer program that measured the
thymine dimer and 8-OHdg-staining cells in the epidermis and dermis.
The most notable conclusion of this study is the finding that low-dose beta-carotene
supplementation is encouraged and demonstrated as effective to prevent and repair photoaging.
Within this finding, Cho at el. also found that oxidative damage in UV-irradiated Skin was
reduced in low-dose beta-carotene group. Oxidative damage was assessed via 8-OHdG
immunostaining, both groups showed a decrease in staining after supplementation with betacarotene, however only the low-dose group showed significantly reduced 8-OHdg staining (See
fig. 6) decreasing from 273.5 +/- 40.2 per x 200 field to 190.5 +/- 21.8 (p= 0.03)(1). In addition,
Cho at el. learned that facial wrinkles and elasticity were improved in low-beta-Carotene group.
Facial wrinkles were measured before and after beta-Carotene intake, and the low-dose group’s
facial wrinkles drastically improved in 90 days of beta-carotene supplementation, as suggested
by the visiometer readings R1-R5 decreasing all in P-value. The decrease in R-values indicates a
decrease in wrinkles. (See Fig. 1)(1). In regards to skin elasticity, the cutometer readings
indicated that R2, R5, and R7 values increased in the low-dose group indicating an increase in
cutaneous elasticity (See Table 1)(1). Cho at el. Further concludes that wrinkles were improved
in 3/5 categories for low dose groups only and doses at 90 mg/ day may have deleterious effects.
These findings relate to the authors purpose because based on the study measures the authors
were able to come to the conclusion that low-dose beta-carotene supplementation does in fact
provide effective in preventing and healing photoaging skin.
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Danielle Selden- Vitamin A Critique Paper
Possible limitations of this article that could have affected the results of the study are the
lack of a double-bind study and the lack of dietary considerations in the patients. The
researchers never considered diet, which could have drastically altered the actual beta-carotene
intake if the women were already consuming beta-carotene in their diet. Furthermore, none of
the women in the sample were asked about fat intake. This study was conducted in Seoul Korea,
which has a traditional diet that consists mostly low-fat meat and highly nutritious vegetables.
Fat intake can also alter the rate of absorption of vitamin A. In reference to the type of sample,
there were only 30 patients with no comparison/ placebo group. As previously noted, the
baseline was used as the control group. Important information could have been missed or
overlooked with this type of sample. It would behoove the researchers to conduct a further study
with a larger sample size, a control group, and perhaps in a different country with different
dietary preferences.
With the above findings I feel that Cho at el.’s results supported their stated purpose of
the study: to confirm that beta-carotene does have positive anti-oxidant affects on photoaging
skin; the low-dose group who supplemented with beta-carotene confirmed this. Furthermore as
proposed in the purpose of this study, beta-carotene may demonstrate pro-oxidant qualities. Cho
at el. Noted the pro-oxidant prediction may have some validity; that there may be a threshold
dosage past which the beneficial action of beta-carotene plateaus and possibly diminishes,
working in the opposite direction to adversely affecting the skin function (1). I feel that the
authors were realistic with their results, as they acknowledged that the high-dose group of betacarotene needed further study, as suggested by the pro-oxidant results. I consequently agree with
the authors that further study needs to be completed but I do believe that the results in regard to
the low-dose beta-carotene are significant and should be considered by consumers and the
medical community.
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Danielle Selden- Vitamin A Critique Paper
Citations
1. Cho S, Lee D H, Won C et al. Differential effects of low-dose and high-dose beta-carotene
supplementation on the signs of photoaging and type I procollagen gene expression in human
skin in vivo. Dermatology. 2010; 221: 160-171.
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