Effects of Dried Brewer`s Yeast on Skin and QOL: A Single

Received: Oct. 27, 2009
Accepted: Jan. 21, 2010
Published online: Feb. 24, 2010
Original Article
Effects of Dried Brewer’s Yeast on Skin and QOL:
A Single-Blind Placebo-Controlled Clinical Study of 8-Week Treatment
Sawako Hibino 1), Umenoi Hamada 2), Hozumi Takahashi 2), Miwako Watanabe 3), Naoko Nozato 4),
Yoshikazu Yonei 2)
1) Faculty of Health Sciences, Morinomiya University of Medical Sciences
2) Anti-Aging Medical Research Center, Graduate School of Life and Medical Science, Doshisha University
3) Mareesia Garden Clinic
4) Trend Analysis Section, Department of Research & Development, Asahi Breweries Limited.
Abstract
Objective: Brewer’s yeast contains vitamins, minerals, amino acids and other nutrients, and has been reported to control intestinal
function as well as to exert anti-ulceration, anti-tumor and anti-allergy effects. The present study evaluated the effects of oral
treatment with dried brewer’s yeast tablets (study product) on skin in a single-blind placebo-controlled design in humans.
Methods: Thirty-two healthy volunteer women (37.0±4.8 years) were allocated as follows: Group E-30 (n=11) were treated with
30 tablets/day of the study product (containing 7,125mg/day of dried brewer’s yeast), Group E-9 (n=10) were given 9 tablets/day
of the study product, and the control group (n=11) were given 30 placebo tablets/day. The treatment period was 8 weeks. Two
patients prematurely discontinued the study (discontinuation rate: 5.9%) and were excluded from the analyses. The study product
(Ebios Tablet®) was provided by Asahi Food & Healthcare Co., Ltd. Before and at 4 and 8 weeks after the study, subjective
symptoms were evaluated using the Anti-Aging QOL Common Questionnaire (AAQol) and checking skin symptoms, skin
images were analyzed with SK Info (SKI, Integral Co.) and Aphrodite-III (PSI), and skin color (CM-700d, Konica Minolta
Sensing, Inc.) and elasticity (Cutometer MPA580, Courage & Khazaka electronic GmbH) were measured.
Results: In Group E-30, the AAQol physical symptom “cold skin” score was significantly improved at 8 weeks (p<0.05). The
skin symptoms “make-up runs easily” and “desiccated and gritty skin,” as well as the physical symptom “menstruation-related
troubles” were improved in a significant and dose-dependent way from the control group (p<0.01). On skin analysis, SKI
demonstrated an increase in moisture content (15.4%, p=0.010), decrease in erythema (– 18.3%, p<0.001) and increase in
elasticity (13.3%, p=0.003), while PSI revealed an increase in hydration (Total: 14.5%, T zone: 13.7%, U zone: 18.2%, p<0.01)
and decrease in pores (– 32.7%, p=0.022). Cutometer analysis showed a dose-dependent increase in skin elasticity, while analysis
of skin color showed a decrease in hemoglobin (– 9.5%, p=0.016), improved lightness (– 0.7%, p=0.045) and decrease in redness
(– 8.3%, p=0.013). During the study period, no serious adverse events were noted.
Conclusion: These results suggest that treatment with dried brewer’s yeast is useful in improving skin condition, e.g. moisture
content and elasticity, and also QOL.
KEY WORDS: dried brewer’s yeast, freckles, wrinkles, skin elasticity, moisture content of skin
Introduction
We have previously investigated the effects of cosmetics 13),
supplements 14,15) and health foods 16) on skin from the viewpoint
of Anti-Aging Medicine using common objective parameters using
a skin imaging and analyzing device. Here, we investigated the
effects of dried brewer’s yeast on human skin and QOL in a
single-blind placebo-controlled clinical study.
Dried products made from the yeast used for brewing beer
contain a range of nutrients, including vitamins, minerals, amino
acids, dietary fiber, and nucleic acids. Dried brewer’s yeast
products are used as quasi-drugs and foods with health claims
(foods with nutrient function claims) in Japan. Animal
experiments and clinical studies have demonstrated that dried
brewer’s yeast is effective in improving diabetes mellitus 1),
promoting ferrous iron absorption 2), controlling intestinal
functions 3), improving lipid metabolism, e.g. decreasing
LDL-cholesterol levels 4), and exerting anti-ulceration 5,6) and
anti-tumor effects 7). Several reviews have also appeared 8-12).
Anti-Aging Medicine 7 (4) : 18-25, 2010
(c) Japanese Society of Anti-Aging Medicine
Associate Prof. Sawako Hibino,
Faculty of Health Sciences, Morinomiya University of Medical Sciences
1-26-16, Nanko-Kita, Suminoe-ku, Osaka City, Osaka 559-0034 Japan
Tel: +81-(0)6-6616-6911 / Fax: +81-(0)6-6616-6912 / E-mail: [email protected]
18
Prof. Yoshikazu Yonei, M.D., Ph.D.
Anti-Aging Medical Research Center, Graduate School of Life and Medical Science, Doshisha University
1-3, Tatara Miyakodani, Kyotanabe city, Kyoto 610-0321 Japan
Tel & Fax: +81-(0)774-65-6394 / E-mali: [email protected]
Table 1
Subjects and Methods
Major nutritional ingredients typically found
in dried brewer’s yeast*
* Content may vary to some extent since this is a natural product
Subjects
Thirty-four healthy volunteer women (mean age: 36.9±4.7years)
were randomly divided into one of three groups, Group E-30
(n=12), Group E-9 (n=11), and a control group (n=11). After
excluding one subject each who withdrew from Groups E-30 and
E-9 (discontinuation rate 5.9%), 32 subjects were included in the
analysis, consisting of 11 in Group E-30, 10 in Group E-9 and 11
in the control group (mean age: 37.0±4.8 years).
(1) General composition(%)
Crude protein
37 - 50
Mineral
6 - 10
Carbohydrates
25 - 40
(soluble nitrogen-free substances)
Fiber
Fat
Moisture
1 - 10
1 - 3
4 - 9
(2) Vitamins (µg/g)
Thiamine (B1)
Riboflavin (B2)
Nicotinic acid
Pyridoxine (B6)
Folic acid
Biotin
Study Design
The present study was a single-blind placebo-controlled clinical
trial. Groups E-30 and E-9 received 30 tablets/day (containing
7,125mg/day of dried brewer’s yeast) and 9 tablets/day of the
study product, respectively, and the control group received 30
placebo tablets/day, for 8 weeks. During this period, subject
condition was checked on three predetermined observation days.
The study product contained dried brewer’s yeast (Ebios Tablet®
237.5 mg; Asahi Food & Healthcare Co., Ltd., Sumida-ku, Tokyo).
Table 1 shows the major nutritional ingredients typically found in
dried brewer’s yeast. One placebo tablet (250 mg) contained
crystal cellulose (Ceolus UF-F702) at 99% and lubricant (calcium
stearate) at 1%.
Each subject took the prescribed number of tablets three times
daily after meals. The subjects were instructed to take the study
product even if they did not have a meal. When they forgot to take
the study product, they were instructed as follows: if they noticed
the missed dose during the same day, they were to immediately
take the missing dose; and if they noticed the missed dose on the
following day or later, they were to miss that dose.
Regarding lifestyle-related habits, the subjects were instructed
to avoid excessive eating, very demanding exercise, and lack of
sleep. They were also instructed to continue the same alcohol
consumption habits as before.
The subjects maintained a “diary” every day. Those responsible
for checking the diaries determined if their lifestyle-related habits
had changed, and whenever the investigator found anything which
required improvement, he/she informed the subject. On each
observation day, the subjects recorded their recent health condition
in a “Health Condition Report” form.
21 22 100 60.1 0.5 -
360
80
1000
100
80
3.6
p - aminobenzoic acid
9 - 800
Choline
3500 - 5300
Pantothenic acid
20 - 350
Vitamin B12
0.001 - 0.004
Inositol
2700 - 5000
(3) Nitrogen-containing ingredients (%)
Pure protein
64 –76 of previous N
RNA
3-9
DNA
0.2 - 0.5
Glutathione
0.5 - 1
Composition of amino acids
Isoleucine
Leucine
Lysine
Methionine
Phenylalanine
Threonine
Tryptophan
Valine
Alanine
2.1
2.6
2.6
0.6
1.0
1.9
0.5
2.2
2.7
-
3.1
7.2
4.5
1.6
2.5
4.3
0.9
4.9
4.8
Arginine
Aspartic acid
Cystine
Glutamic acid
Glycine
Histidine
Proline
Serine
Tyrosine
1.5
3.9
0.1
5.6
2.6
1.0
- 3.0
- 6.8
- 1.5
- 10.4
- 3.2
- 2.1
2.1
1.3 - 4.7
1.8 - 2.2
(4) Carbohydrates (%)
Glycogen
Trehalose
3 - 25
1
Glucan
Mannan
6 - 8
4 - 6
(5) Lipid (%)
Fat
Phospholipid
0.9
0.8
Ergosterol
0.2 - 1.4
45 - 59
28 - 48
0.1 - 2.5
Calcium
Magnesium
Silica
1.0 - 4.5
4.0 - 8.1
0.1 - 1.6
Cobalt
Chrome
Selenium
0.5
0.1 - 0.2
0.16
(6) Inorganic ingredients (%)
Phosphorus
Potassium
Sodium
Evaluation Methods
(7) Trace ingredients (mg/100g)
Subjective symptoms were divided into two categories,
physical symptoms and mental symptoms, and rated as described
in our previous study according to a 5-grade scale ranging from
1 to 5 points using the Anti-Aging QOL Common Questionnaire
(AAQol) 17). This Questionnaire was downloaded from the
Web site of the Japanese Society of Anti-Aging Medicine
(http://www.anti-aging.gr.jp/anti/clinical.html).
Facial skin was evaluated at two sites, i.e. the right cheek and
the left cheek, for the volume of moisture, sebum, melanin and
erythema, as reported previously 13). The amount of moisture
contained in the stratum corneum was determined with a skin
moisture analyzer (corneometer) (CM825SPANC, Courage &
Khazaka electric GmbH, Cologne, Germany) 18) using the
phenomenon that the electrical capacitance of the skin varies
depending on its moisture content. Sebum volume was determined
with a skin sebum analyzer (sebumeter) (SM810SPANC, Courage
& Khazaka electric GmbH) 19), which measures changes in
transmittance through a dedicated film. The volume of melanin in
Copper
Zinc
Manganese
9 - 10
5
0.5
the skin and degree of erythema were measured with a mexameter
(MX18, Courage & Khazaka electric GmbH), which irradiates the
skin with light of a specific wavelength and measures the reflected
light using a light diode to calculate the melanin and erythema
indices 18). These parameters were recorded with an SK Info®
(Integral Corporation, Shinjuku-ku, Tokyo) (hereinafter referred to
as SKI), which integrates various measurement devices.
Skin images were analyzed with the Skin Diagnosis System
Aphrodite-III system (PSI Co., Ltd., Seoul, Korea) (hereinafter
referred to as PSI) to evaluate oil content, total moisture content,
excess keratin, pores, and wrinkles at the corner of the eye. Skin
color was determined with a spectrophotometer (CM-700d,
19
Effects of Dried Brewer’s Yeast on Skin and QOL
Konica Minolta Sensing, Inc., Sakai-city, Osaka). As previously
reported 20), skin elasticity was determined with a Cutometer
(MPA580, Courage & Khazaka electric GmbH) 21). Skin hydration
was evaluated with a moisture content analyzer (corneometer)
(CM825, Courage & Khazaka electric GmbH) 22).
The present study was performed between March 6 and May
2, 2009. The climate condition around the study area was shown in
Table 2 23). All study participants received an explanation regarding
how to take the study product either by a documented information
form or by participation in an explanatory meeting at the medical
institution where this study was performed (Mareesia Garden
Clinic, Shinjuku-ku, Tokyo). The study subjects understood that
even if they had given consent to participate in the study, they
were free to express the desire to withdraw from the study on their
own volition at any time during the study period without being
disadvantaged in any way.
Table 2
Results
Results of the Questionnair
Comparison of scores before and 8 weeks after the study in
Group E-30 revealed that among the AAQol physical symptoms,
“cold skin” was improved (p=0.026) and “blurred vision” was
worsened (p=0.026) at 8 weeks after the study (Table 3). The
additional symptom “menstruation-related troubles” also improved
(p=0.038). With regard to mental symptoms, none of these
improved whereas “inability to solve problems” worsened
(p=0.046). For skin symptoms, improvement was noted in
“make-up runs easily” (p=0.011) and “desiccated and gritty skin”
(p=0.005), while “dull, fragile nails” was worsened (p=0.038).
On comparison of the E-30 and control groups, the following
changes in symptoms between baseline and 8 weeks differed,
namely the physical symptoms “lethargy” (p=0.018), “skin
problems” (p=0.003), and “menstruation-related troubles”
(p=0.006); mental symptom “irritability” (p=0.031); and skin
symptoms “make-up runs easily” (p=0.002), “course skin”
(p=0.012), “desiccated and gritty skin” (p=0.003), and “thinning
eyebrows” (p=0.011). Group E-30 demonstrated the favorable
effects of the study product in all changes.
The relationship between the number of study tablets
prescribed and the change from baseline for each symptom at 8
weeks after the start of the study was evaluated to determine the
presence of dose-dependence. Dose-dependent changes were noted
for “skin problems” (p=– 0.50, p<0.01), “menstruation-related
troubles” (p<0.05), “inability to solve problems” (p=0.36, p<0.05),
“make-up runs easily” (p=0.54, p<0.01), “course skin” (p=– 0.45,
p<0.05), “desiccated and gritty skin” (p=– 0.58, p<0.01), “skin
sagging or swollen” (p=– 0.38, p<0.05), “no tone or complexion”
(p=– 0.36, p<0.05) and “thinning eyebrows” (p=– 0.43, p<0.05).
Changes were favorable for all symptoms excluding “inability to
solve problems.”
Climate information during the observation term
February
Average temperature
°C
minimun
°C
maximum
°C
Avarage humidity
%
Duration of sunshine hour
UV amount*
Erythemal UV
kJ/m2
UV-B
kJ/m2
7.8
11.5
4.4
50.0
131.2
March
April
May
0
4 weeks
8 weeks
10.0
13.7
6.3
48.0
162.9
15.7
20.2
11.9
54.0
226.7
20.1
23.6
16.9
64.0
154.6
1.08 ± 0.13 1.54 ± 0.13 2.46 ± 0.19 2.60 ± 0.18
8.24 ± 0.93 11.75 ± 1.00 18.86 ± 1.47 19.81 ± 1.40
Data were obtained from the website of Japan Meteorological Agency in 2009 23).
*UV amount: daily amount of ultraviolet. Data are expresse as a monthly average.
Ethical Considerations and Declaration of No
Commercial Relationship
Skin Analysis
The study was performed at a third party institution in
compliance with the ethical principles of the Declaration of
Helsinki and the Personal Information Protection Law, and by
reference to the “Ordinance regarding the Good Clinical Practice
(GCP)” (MHW Ordinance No. 28 dated March 27, 1997). At the
medical institution which performed the study, an ethical
committee for clinical studies held meetings to review the ethical
justification and validity of the study. This study was approved by
the committee and conducted according to the approved protocol.
Through the authority of Doshisha University, the laboratory
of the authors was financially supported by Asahi Food &
Healthcare Co., Ltd. and Asahi Breweries Foundation (Sumida-ku,
Tokyo) for this study. The authors have no commercial
relationship with companies related to the field of the study. The
activities of the laboratory are annually declared to the Committee
of “Conflicts of Interests”.
Measurement with SKI (using two-sided mean values) in
Group E-30 revealed the following improvements: increased
moisture content (+15.4%, p=0.010), reduced erythema (– 18.3%,
p<0.001), and increased elasticity (+13.3%, p=0.003) (Table 4).
Melanin significantly increased (+14.2%, p=0.031) in Group E-30
as was seen in the control. Inter-group analysis with the control
group showed no significant differences in any of these parameters.
Measurement with PSI in Group E-30 revealed improvements
at 8 weeks after the start of the study in total moisture content
(+14.5%, p=0.003), hydration (T zone) (+13.7%, p=0.003),
hydration (U zone) (+18.2%, p=0.020), and pores (– 32.7%,
p=0.022) (Table 5). Inter-group comparison demonstrated that
among these parameters, total moisture content (p=0.015) and
hydration (T zone) (p=0.016) showed more favorable effects in
Group E-30 than in the control group. For “hydration (T zone),”
the change from baseline noted at 8 weeks after the start of the
study was dose-dependent (p=0.35, p<0.05) (Fig.1).
Skin color measurement (using two-sided mean values)
demonstrated improvements at 8 weeks in hemoglobin index
( – 9.5%, p=0.016), lightness (L*) (+0.7%, p=0.045), and redness
(a*) (– 8.3%, p=0.013) (Table 6). Inter-group analysis showed no
significant difference between Group E-30 and the control group.
With regard to lightness, the change from baseline noted at 8
weeks after the start of the study was dose-dependent (p=0.36,
p<0.05) (Fig.2).
Determination of skin elasticity with the Cutometer (using
two-sided mean values) revealed that R0, which decreases as skin
Statistical Analysis
Statistical analyses were performed using the statistical analysis
software Dr.SPSSII (SPSS Japan Inc., Shibuya-ku, Tokyo) and
Excel Tokei (Social Survey Research Information Co., Ltd.,
Shinjuku-ku, Tokyo). ANOVA, paired t-test for comparisons
before and after treatment, inter-group analyses and analysis of
correlations were all two-tailed, and results were considered
significant at the <5% level.
20
Table 3
Anti-Aging QOL Common Questionnaire and skin symptoms
Group E-30
Physical symptoms
Before(0w)
Blurred vision
Lethargy
Skin problems
Cold skin
Menstruation-related troubles
±
±
±
±
±
8 weeks after
±
±
±
±
±
Inter-group
analysis
Control group
p value
Before(0w)
±
±
±
±
±
8 weeks after
±
±
±
±
±
p value
vs. control
1.08
1.19
0.94
1.36
1.33
0.026
0.724
0.089
0.026
0.038
2.36
2.18
2.36
3.09
2.18
0.93
0.90
1.10
1.10
1.37
0.553
0.025
0.016
0.001
0.082
0.221
0.018
0.003
0.357
0.006
2.00 ± 0.77 1.64 ± 0.67
1.55 ± 0.93 2.18 ± 0.75
0.104
0.046
2.18 ± 1.17 2.45 ± 1.13
2.27 ± 1.19 2.36 ± 1.12
0.391
0.588
0.031
0.054
0.052
0.104
0.104
0.493
0.676
1.000
0.420
1.000
0.011
0.441
0.176
0.756
0.070
0.005
0.132
0.064
0.676
0.360
0.341
0.506
0.756
0.724
0.192
0.659
0.588
0.277
0.038
3.36
3.27
3.36
3.36
3.09
3.27
2.00
3.45
2.27
2.45
2.36
2.09
2.18
2.18
3.00
3.09
2.73
2.91
3.00
2.36
2.91
3.00
1.45
2.73
2.64
2.00
2.36
1.000
1.000
0.341
0.588
0.676
0.588
0.242
0.441
0.096
0.756
0.724
0.138
0.111
0.064
0.307
1.000
0.779
0.216
0.052
0.221
0.676
0.441
0.053
0.192
0.724
0.756
0.242
0.081
0.164
0.330
0.377
0.506
0.534
0.164
0.611
0.002
0.717
0.108
0.051
0.012
0.003
0.057
0.123
0.637
0.083
0.684
0.170
0.947
0.429
0.011
0.302
0.550
0.338
0.290
1.55
1.82
2.73
3.00
2.55
0.93
0.87
0.90
1.61
1.44
2.18
1.73
2.09
2.36
2.18
0.92
1.17
0.92
1.22
1.25
2.55
2.73
3.27
2.27
2.45
Mental symptoms
Irritability
Inability to solve problems
Skin symptoms
Noticeable pores
Noticeable blackheads in pores
Concerned about extension of pores
Dry skin
Concerned about dull skin
Frequent pimples
Itchy skin
Concerned about spots or
Make-up runs easily
Poor complexion
Oily face
Sticky or dirty skin
Coarse skin
Desiccated and gritty skin
Slackened skin
Not elastic, not glossy
Concerned about crows feet
Concerned about rough skin
Rough dry skin during
Bags under eyes
Corner of eyes sagging
Corners of mouth sagging
Thinning eyebrows
Fat chin
Thinning hair
Slow growing nails
Dull, fragile nails
3.91
3.36
3.91
4.36
3.36
2.82
2.09
3.91
3.55
2.18
2.36
2.00
2.73
3.36
4.27
4.18
3.09
3.45
2.91
1.91
3.09
3.18
1.73
3.00
1.91
1.36
2.18
±
±
±
±
±
±
±
±
±
±
±
±
±
±
±
±
±
±
±
±
±
±
±
±
±
±
±
1.04
1.36
1.38
0.81
1.21
1.40
1.58
1.30
1.13
1.08
1.21
0.77
1.10
0.81
0.79
0.98
1.38
1.13
1.58
0.83
1.45
1.47
1.19
1.34
0.83
0.50
1.40
3.36
3.00
3.55
4.09
3.45
2.82
1.73
3.91
2.73
2.36
1.91
1.91
2.00
2.55
3.64
3.27
3.00
3.00
3.27
1.73
3.18
3.09
1.45
2.82
2.00
1.64
2.55
±
±
±
±
±
±
±
±
±
±
±
±
±
±
±
±
±
±
±
±
±
±
±
±
±
±
±
1.21
1.26
1.44
0.70
1.37
1.33
0.79
1.04
1.19
1.12
1.22
1.14
0.63
0.69
1.12
1.27
1.10
1.34
1.27
0.65
1.40
1.30
0.69
1.40
1.00
0.81
1.63
±
±
±
±
±
±
±
±
±
±
±
±
±
±
±
±
±
±
±
±
±
±
±
±
±
±
±
1.12
0.90
1.21
0.81
0.94
1.49
0.77
0.82
0.90
0.93
1.43
1.30
0.75
0.60
1.34
1.04
1.10
0.94
1.26
0.92
1.14
0.89
0.52
1.42
1.29
0.63
1.43
3.36
3.27
3.18
3.55
3.00
3.18
2.45
3.64
2.73
2.55
2.45
2.55
2.73
3.09
3.36
3.09
2.82
3.45
3.55
2.73
3.00
3.18
1.91
3.00
2.55
1.91
2.82
±
±
±
±
±
±
±
±
±
±
±
±
±
±
±
±
±
±
±
±
±
±
±
±
±
±
±
0.81
0.79
0.98
0.82
1.18
1.40
0.93
0.81
0.90
0.93
1.21
1.04
1.27
1.14
0.92
1.04
1.08
1.13
1.21
0.90
1.00
0.87
0.83
1.18
1.13
0.70
1.33
Group E-30 : n=11, Control group : n=11.
Mean±SD.
Table 4
Skin analysis: Measurement with SKI using mean values of the both sides
Group E-30
Before(0w)
Sebum
Moisture
Melanin
Erythema
Elasticity
0.00
59.75
101.15
323.41
52.64
±
±
±
±
±
0.00
6.17
30.48
62.29
4.48
8 weeks after
p value
±
±
±
±
±
ND
0.010
0.031
0.000
0.003
0.00
68.95
115.50
264.18
59.64
Inter-group
analysis
Control group
0.00
10.24
29.60
47.67
5.81
Before(0w)
0.00
60.71
117.94
294.41
51.91
±
±
±
±
±
Group E-30 : n=11, Control group : n=11.
Mean±SD, ND : not detected.
21
0.00
10.59
32.48
59.19
4.29
8 weeks after
0.00
63.95
128.64
245.86
56.55
±
±
±
±
±
0.00
13.02
28.18
49.52
6.31
p value
vs. control
ND
0.424
0.049
0.000
0.025
ND
0.228
0.390
0.454
0.356
Effects of Dried Brewer’s Yeast on Skin and QOL
Table 5
Skin analysis: Measurement with PSI using mean values of the both side
Group E-30
Before(0w)
Oil
T zone
Oil
U zone
Total moisture content
Excess keratin
Hydration
T zone
Hydration
U zone
Pores
Wrinkles at the corner
of the eye
0.42
0.11
47.64
12.88
35.18
27.00
16021
0.12
±
±
±
±
±
±
±
±
0.46
0.32
8.92
8.16
8.93
3.44
7577
0.02
8 weeks after
p value
±
±
±
±
±
±
±
±
0.365
0.292
0.003
0.585
0.003
0.020
0.022
0.510
0.34
0.04
54.55
11.09
39.99
31.91
10785
0.11
Inter-group
analysis
Control group
0.32
0.09
8.18
8.52
7.76
6.41
3923
0.02
Before(0w)
0.43
0.09
46.91
6.19
31.03
26.36
18532
0.13
±
±
±
±
±
±
±
±
0.52
0.15
5.49
4.95
4.53
6.04
4223
0.03
8 weeks after
p value
vs. control
±
±
±
±
±
±
±
±
0.866
0.452
0.621
0.326
0.227
0.649
0.063
0.082
0.523
0.251
0.015
0.175
0.016
0.175
0.101
0.474
0.45
0.06
47.64
7.71
32.13
27.36
16770
0.12
0.58
0.08
6.14
4.78
6.31
5.57
3299
0.02
Group E-30 : n=11, Control group : n=11.
Mean±SD.
Table 6
Skin color measurement using mean values of the both sides
Group E-30
Before(0w)
Index for the volume of melanin
Hemoglobin index
Lightness(L*)
Redness(a*)
Yellowness(b*)
0.99
1.46
66.43
10.61
16.37
±
±
±
±
±
8 weeks after
0.12
0.32
1.61
1.66
2.34
0.98
1.32
66.87
9.73
16.48
±
±
±
±
±
0.14
0.26
1.66
1.45
2.15
Inter-group
analysis
Control group
p value
Before(0w)
0.439
0.016
0.045
0.013
0.682
0.96
1.24
68.36
9.26
16.58
±
±
±
±
±
8 weeks after
0.12
0.28
2.60
1.89
1.12
0.96
1.22
68.08
9.08
16.55
±
±
±
±
±
0.15
0.24
2.78
1.75
1.20
p value
vs. control
0.977
0.734
0.388
0.612
0.934
0.577
0.120
0.063
0.133
0.730
Group E-30 : n=11, Control group : n=11.
Mean±SD.
Fig. 1. Dose-dependent change from baseline in moisture content (T zone)
Fig. 2. Change from baseline in lightness (L*) determined by skin color analysis.
determined with PSI. * p < 0.05 vs control. Mean ± SEM, E-30 : n=11,
E-9 : n=10, Control : n=11.
Table 7
Mean ± SEM, E-30 : n=11, E-9 : n=10, Control : n=11.
Skin elasticity test and perspiration volume test using mean values of both sides
Group E-30
Skin elasticity index
R0
R1
R2
R6
R7
Volume of perspiration
Before(0w)
0.25
0.09
0.64
0.49
0.30
±
±
±
±
±
0.04
0.02
0.08
0.09
0.06
29.05 ± 5.26
8 weeks after
±
±
±
±
±
p value
0.03
0.01
0.06
0.11
0.04
0.006
0.030
0.864
0.405
0.648
30.11 ± 5.98
0.625
0.23
0.08
0.64
0.52
0.31
Inter-group
analysis
Control group
Before(0w)
0.25
0.08
0.66
0.48
0.33
±
±
±
±
±
0.03
0.01
0.06
0.09
0.04
27.07 ± 7.14
Group E-30 : n=11, Control group : n=11.
Mean±SD.
22
8 weeks after
p value
vs. control
0.03
0.01
0.06
0.09
0.04
0.225
0.040
0.036
0.630
0.094
0.084
0.003
0.047
0.313
0.068
27.14 ± 5.30
0.966
0.710
0.24
0.09
0.63
0.47
0.31
±
±
±
±
±
loses elasticity, decreased in Group E-30 (– 9.5%, p=0.006),
although inter-group analysis showed no significant difference
between Group E-30 and the control group (Table 7). R1, which
decreases as the capability to return to the original state increases,
decreased (– 8.6%, p=0.030), and more favorable effects were
noted in Group E-30 than in the control group (inter-group
analysis: p=0.003). R2, which represents the viscoelasticity of the
skin and is considered the most reliable index, did not change
significantly after 8 weeks (+0.4%, p=0.864), although more
favorable effects were noted in Group E-30 than in the control
group (inter-group analysis: p=0.047) (Fig.3). Dose-dependency
was observed in the change from baseline for R1 (p=0.50, p<0.01)
and from baseline for R5 (p=0.37, p<0.05). The change from
baseline for R2 was significantly correlated to the change from
baseline for R1 (p<0.01).
On the 44th day of treatment, a 33-year-old woman in Group
E-30 went to an open-air concert and stayed for 2 hours in strong,
direct exposure to the sun. On the 46th day, small rashes appeared
on her face and neck, and on day 48 she stopped taking the study
product. On the 51st day, the flare had extended over the entire
face. She visited a dermatology clinic where photosensitivity was
diagnosed, and treatment with a topical steroid was begun
(Kindavate® 0.5 grams/day). On the 55th day, the symptom was
relieved. She had experienced similar symptoms once in the past
but the cause was unknown. The event was diagnosed as an
incidental “photosensitivity” and determined “unrelated” to the
study product.
Evaluation of Adverse Events
A 37-year-old woman in Group E-9 who used a face mask due
to pollinosis for two days developed rashes on her jaw on the
second day of treatment. These gradually increased and by day 13
had extended over the entire jaw. On day 15, treatment with the
study product was discontinued, and the rash was treated with
Locoid® (steroid), Azunol® (for topical use), Sato Salbe 10® (for
topical use) and Allegra® (oral medicine). On the 18th day, the
symptoms were resolved. This event was diagnosed as incidental
contact dermatitis related to the face mask, and was rated as
“unrelated” to the study product.
Fig. 2. Dose-dependent change from baseline in skin elasticity indices R0, R1, R2 and R5 determined with Cutometer. * p < 0.05 vs control. Mean ± SEM, E-30 : n=11, E-9 :
n=10, Control : n=11.
23
Effects of Dried Brewer’s Yeast on Skin and QOL
Discussion
The present study has provided interesting results regarding
the effects of dried brewer’s yeast on the skin. Yeast first improved
moisture content of the skin, and second improved elasticity. For
moisture content, the significant improvement in the subjective
symptom “desiccated and gritty skin” was supported by the
improved moisture content of skin as determined by SKI and PSI.
This finding appears highly reliable, since dose-dependence was
confirmed in the 3 groups, i.e. the control group as well as Groups
E-9 and E-30. For elasticity, measurements with a Cutometer and
SKI confirmed the significant improvement in elasticity. Among
Cutometer-related parameters, results showed that the most
reliable, R2, was significantly different between Group E-30 and
the control group at 8 weeks, which also supports the reliability of
these findings.
Very few studies have investigated the effect of yeast on skin,
and no report could clearly explain the mechanism of
improvement in moisture content and elasticity. Yeast extract from
Saccharomycopsis was reported to inhibit, via gene expression of
heme-oxigenase-1, the nitric oxide from macrophages, thus
preventing the damage of epidermal cells 24). Antioxidant-enriched
yeast may promote the ability of regeneration and protect the skin
against doxorubicin toxicity 25). These results indicate that the
supplementation of yeast as an anti-oxidant may prevent the
damage of epidermal cells and enhance the ability of tissue
regeneration. It is also possible to prevent the oxidative damage of
collagen which plays a role to keep the skin elasticity. When the
regeneration of the skin is activated, it also promotes the synthesis
of collagen and ceramide which acts as a skin moisturizer. This
may be a reason that the dried brewer’s yeast improved the skin
elasticity and moisture amount in this study. In healthy adult men
who used skincare cosmetics containing hydrolyzed yeast for 2
weeks, evaluation of effects on the skin by skin imaging revealed
improvements in crows feet (wrinkles and stickiness at the corner
of the eye) 26). This result is compatible with the present findings.
Comparison of skin color before and after the study showed
an improvement in Group E-30 in the volume of melanin and
lightness. This finding suggests that some ingredients of dried
brewer ’s yeast, which include glutathione (γ-glutamine
cysteinylglycine: GSH), biotin, nicotinic acid (niacin), vitamin B12
and essential amino acids such as tryptophan, are involved in the
effects of yeast on the skin 27-30). Among these substances, GSH in
particular decreases with aging 31) and is involved in the
proliferation and differentiation of neurocytes 32). GSH deficiency
induces neurodegeneration through oxidative stress 33), and GSH is
decreased in patients with Alzheimer disease 34). More recently, its
effect as a depigmenting agent has been reported 35).
Biotin is essential to the maintenance of healthy skin and
wound healing 36,37). Biotin deficiency induces skin diseases or
alopecia 38,39).
Tryptophan is involved in the synthesis of melanin, which has
an antioxidant effect 40,41). In the skin, it has been reported that
melanin protects the skin against ultraviolet rays 42,43) and reduces
pigmentation so as to produce bright-looking skin 44).
The state of the skin generally reflects the physical status such
as gastrointestinal function. In the state of constipation, the
amount of fermenting and degenerated products in intestines
increases. These products shift into blood, and it becomes a cause
to deteriolize the skin function 45). The brewers dried yeast is
shown to improve the bowel movement 46,47). It is also reported
that the dry yeast addition yogurt intake improves the intestinal
environment of bacterial flora 48). These factors maybe play a role
in contributing to the improvement of skin function, although
“constipation” score was not significantly changed in this study.
24
A serious side effect is not reported to the cellulose crystalline
used as a placebo. It can explain the data change seen in the
control group by the climatic difference. The skin test was done in
March, April, and May. Meanwhile, the rise in the temperature and
humidity, and the increase of durations of sunshine and the amount
of ultraviolet rays were admitted (Table 2) 23). Especially, an
increase of UV-B causes various troubles in the skin 49). In this
study, the melanin amount in control showed significant increase
(Table 4), and the skin elasticity seemed affected (Fig.3) although
it was not significant. Also in the previous study performed in June,
July and August 16), the increased UV sure caused the
augmentation of pigmented lesions and melanin amount. The skin
moisture amount in control seemed affected (Fig.1) in relation to
the rise of humidity, however, it was not significant.
On the other hand, in E-30 group, it is possible that effect is
counterbalanced due to such a disadvantageous condition. Thus, a
significant ameliorating effect might not have been in this study.
The melanin amount admitted a significant increase due to the UV
effect, however the lightness (L*) improved significantly by the
skin color test. It is thought that the lightness improved to the
extent that redness (a*) improves it, because this test is caught
overall in the skin color tone.
During the present study period, 2 subjects prematurely
discontinued the study due to contact dermatitis in one subject in
Group E-9 and photosensitivity in the second in Group E-30. In
both subjects, these events were rated as “unrelated” to the study
product since they were highly incidental. Throughout the study
period, no serious adverse events were noted in the study subjects,
including these discontinuations. Although skin symptom score
“glossless and easily broken nails” has increased significantly in
E-30 group, we did not judge it as a side effect. The reason is that
the extent was negligible and the score rose to the same level as in
control group.
In conclusion, 8-week treatment of premenopausal women with
dried brewer’s yeast at 7,125mg/day produced a significant improvement
in the subjective symptoms “cold skin,” “menstruation-related
troubles,” “make-up runs easily” and “desiccated and gritty skin.”
Further, skin analysis demonstrated a significantly increased
moisture content (about 15%), improved elasticity, and an improved
hemoglobin index. These effects in improving moisture content and
skin elasticity were dose-dependent. Findings suggestive of
unfavorable effects were increased scores for the subjective
symptoms of “blurred vision,” “inability to solve problems,” and
“glossless and easily broken nails,” and an increased volume of
melanin, as determined by skin analysis, although no serious
adverse events were noted. These results indicate the possibility
that treatment with the study product may be useful in improving
both skin condition and QOL. Brewer’s yeast is a natural
substance containing high levels of nutrients such as protein,
carbohydrates, lipids, minerals, vitamins and dietary fiber, as
shown in Table 1. In the future, brewer’s yeast is expected to be
useful in a variety of fields, since it contains these ingredients in
well-balanced combinations.
Acknowledgment
This study was supported by Asahi Breweries Foundation
(Sumida-ku, Tokyo) in 2009.
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