Glycative Stress Research
Online edition : ISSN 2188-3610
Print edition : ISSN 2188-3602
Received : August 9 2016
Accepted : September 1, 2016
Published online : September 30, 2016

Original Article

Iodine-enriched egg reduced total body fat and visceral fat among normal
individuals: A placebo-controlled, randomized, double-blind study
Jiro Yokoyama 1), Megumi Morioka 1), Hajime Inoue 2), Yoshikazu Yonei 3), Keiichi Suzuki 4),
Kazuo Katoh 4), Sang-Gun Roh 4, 5)
1) Nippon Nosan Corporation, Yokohama, Kanagawa 220 -81460, Japan
2) Dept. of Plastic & Reconstructive Surgery, Div. of Stem Cell Medicine (Endowed Chair by ANGFA Co.)
St. Marianna University School of Medicine, Kawasaki 216-8511, Japan3) Anti-Aging Medical Research Center / Glycative Stress Research Center, Graduate School of Life and Medical Sciences,
Doshisah University, Kyoto, Japan
4) Division of Functional and Developmental Science of Livestock, Graduate School of Agricultural Science,
Tohoku University, Aoba, Sendai 981-8555, Japan
5) Lab of Animal Physiology, Graduate School of Agricultural Science, Tohoku University, Sendai 981-8555, Japan

Abstract

Objectives: This study aimed to evaluate the effects of iodine-enriched egg (IE) on total body fat, visceral fat, body weight,body mass index (BMI), and safety parameters among normal individuals.
Methods: This randomized, double-blind, placebo-controlled study recruited 56 normal individuals (28 men, 28 women;
BMI: 25 – 30 kg/m 2), who were assigned to receive either boiled IE or ordinary egg (OE) each day for 12 weeks. Total body
fat and visceral fat were measured at baseline and 12 weeks using abdominal computed tomography. Body weight, BMI, andblood samples were also evaluated at baseline and week 12.
Results: Although both groups exhibited similar caloric intakes, the IE group exhibited significantly reduced visceral fat
area at week 12, compared to the OE group. In addition, the IE group exhibited a significant reduction in total and visceralfat area, compared to the baseline value. There were no significant differences in the blood parameters between the IE andOE groups. No significant adverse effects were observed.
Conclusion: These results suggest that IE ingestion may help reduce visceral fat.

KEY WORDS: iodine- enriched egg, total body fat, visceral fat
Introduction

Body fat accumulation is regulated by energy intake
and expenditure, and a serious imbalance between these twoprocesses is a major risk factor for cardiovascular disease
and lifestyle-related diseases, such as diabetes, hypertension,
hyperlipidemia, and arteriosclerosis. In this context,
metabolic syndrome is defined as a group of disorders thatinvolve abdominal obesity with high blood glucose levels,
dyslipidemia, and high blood pressure.
Several functional foods and substrates can be used toprevent the accumulation of excess total body fat and visceralfat, and these functional foods have been commonly
incorporated into diets 1). Functional eggs are easily consumed

Corresponding author: Sanggun Roh,
Lab of Animal Physiology, Graduate School of Agricultural Science,
Tohoku University, Sendai 981-8555, Japan
Tel: 81-22-717-8698 Fax: 81-22-717-8701 E-mail: sanggun. roh@tohoku. ac. jp
Co-authors: Yokoyama J, j_yokoyama@nosan.co.jp ;Morioka M, m_morioka@nosan.co.jp ; Inoue H, h2inoue@marianna-u.ac.jp ;Yonei Y, yyonei@mail.doshisha.ac.jp ; Suzuki K, k1suzuki@bios.tohoku.ac.jp ;Katoh K, kato@bios.tohoku.ac.jp

every day, and previous studies have revealed that iodineenriched eggs (IE) protect against diabetes and alter lipid
metabolism 2 - 6). Furthermore, patients with diabetes who
consumed IE for 3 months exhibited significantly lower
blood glucose levels, compared to normal individuals 7).
Moreover, chickens that received egg white from IE exhibited
lower plasma glucose concentrations, compared to chickens
that were fed egg white from ordinary eggs (OE) 8). However,to the best of our knowledge, no studies have evaluated theeffects of IE and OE on body fat accumulation in humans.
Therefore, the present study aimed to evaluate whether
ingesting IE helped reduce total body fat and visceral fat innormal individuals.

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Glycative Stress Research 2016; 3 (3): 172 - 176(c) Society for Glycative Stress ResearchGlycative Stress ResearchMethods

differences. A P-value of < 0.05 was used to identify
statistically significant differences.

Ethical considerations

The present study complied with the ethical principlesof the Declaration of Helsinki (the 2004 clarification by
the World Medical Association General Assembly), Japan’s
Act on the Protection of Personal Information, the Ministryof Health, Labor, and Welfare’s Ordinance regarding Good
Clinical Practice (no. 28; March 27, 1997), and the Ethical
Guidelines for Epidemiological Research (Ministry of Health,Labor, and Welfare; Ministry of Education, Culture, Sports,Science, and Technology). The study’s design was approvedby the Doshisha University Ethics Committee for Scientific
Research Involving Human Subjects (##14 082) and theclinical research ethics board of the Tokyo Synergy Clinic.
All participants provided their informed consent after
receiving a full explanation regarding the study.

Study design

This study used a randomized, double-blind, placebocontrolled design. Participants were recruited from individuals
who were identified by the Department of Anti-Aging
Medicine (Doshisha University, Faculty of Life and MedicalSciences). Individuals were considered eligible if they
were ≥ 20 years old and did not fulfill any of the exclusion
criteria: a food or drug allergy, pregnant or lactating,receiving treatment using medication or follow-up, diabetes
mellitus diagnosis, pronounced cardiopulmonary function
disorder, receiving medication for hypertension, a history ofgastrointestinal surgery, or suspicion of infectious disease.
Some individuals were also excluded from the study basedon the investigator’s discretion.
The included individuals were randomly allocated toreceive one boiled IE (Yodoran Hikari ®) or one OE each day
for 12 weeks. The compositions of OE and IE were shownin Table 1. During the study, the participants were required
to make five clinic visits: a health screening, a baseline
evaluation, after 4 weeks of ingestion, after 8 weeks ofingestion, and at week 12 (4 weeks after the ingestion
period). A well-trained nurse recorded the participants’ bodyweight, height, BMI, and subjective complaints at each visit,and collected blood samples for laboratory testing (collectedduring the morning after a 10 - h fast). The blood test
parameters included levels of triglycerides, total cholesterol,
high-density lipoprotein cholesterol, low-density lipoproteincholesterol, and other metabolites. Self-reported dietarycaloric intakes for the 3 consecutive days before the baseline
and week 12 visits were assessed, and the average daily
caloric intake values were calculated for each participant.

Subcutaneous and visceral fat assessment

Computed tomography (CT) was performed at baseline
and week 12 to measure the subcutaneous and visceral fat
areas at the level of the umbilicus (L4 – L5; Legato Duo CT;
GE Yokogawa Medical Systems, Tokyo, Japan). The visceralfat area was used to evaluate visceral obesity. The CT data
were analyzed using FatScan software.

Statistical analyses

All data were reported as mean ± standard error. The
paired t-test was used to evaluate intra- and inter -group

Results and Discussion

Among the 6 4 individuals who were randomized to thetreatment groups, 5 individuals dropped out because of
personal reasons that were unrelated to the IE or OE. Fiftynine individuals completed the study, although 3 individuals
were excluded during the analysis because of poor compliance(1 individual did not follow the ingestion protocol) or
unreliable CT data (n = 2). Thus, the final analyses evaluate
data from 56 individuals (28 men, 28 women, age: 50.4 ± 6.5
years, body mass index [BMI]: 27.12 ± 1.33 kg/m 2 ). The IE
and OE groups exhibited similar baseline demographic andanthropometric characteristics ( Table 2 ).
The FatScan analyses of the CT data revealed that theIE group exhibited significantly lower week-12 values for
total body fat and visceral fat, compared to the OE group (p= 0.037 and p = 0.001, respectively). However, both groups
exhibited similar week-12 values for BMI, triglyceride
levels, low-density lipoprotein cholesterol levels, and highdensity lipoprotein cholesterol levels ( Table 3 ). Most blood
test parameters did not exhibit time-related intra-groupchanges (e.g., the IE group exhibited similar baseline andweek-12 values for free triiodothyronine and thyroxine).
However, the IE group did exhibit a significant 12-weekincrease in urinary iodine levels.
Our previous study revealed that the treatment of 3T3-L
adipocytes using yolk from IE reduced their fat accumulationand inhibited adipocyte differentiation 9). Another study also
revealed altered lipid metabolism in rats after they ingested
IE, such as higher tissue lipoprotein lipase activity 3). The
present study showed that the pituitary-thyroid axis was notchanged by ingestion of IE. The iodide related components
as iodide peptide of IE responsible for fat accumulation inadipocytes are present in egg yolk. These findings suggestthat the iodide peptide in IE may help directly reduce fat
accumulation in normal individuals, without changing their
thyroid hormone secretions.

Conclusion

The present study revealed three main findings. First,
the IE group exhibited significantly lower total body fat
and visceral fat, compared to the OE group. Second, bothgroups exhibited similar values for body weight, BMI, andblood parameters (e.g., total cholesterol and low-density
lipoprotein cholesterol). Third, none of the participants
reported problematic adverse effects.

Conflicts of interest

The authors have no financial relationship with theorganization that sponsored this study. The sponsor played
no part in the research, data collection, data analysis, writingof the manuscript, or decision to publish.

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Table 1. The composition of OE and IE

IEOE

Crude proteing

12.3

12.3

Crude fatg

9.1

10.3

Crude Carbohydrateg0.80.3

Energykcal

134

151

Iodineμg

130017Iodide peptideμg361

ND

IE, iodine-enriched egg; OE, ordinary egg; ND, Not detected All compositions were shown per
100 grams of edible egg.

Table 2. The participants' baseline characteristics

I E (n = 28)

OE (n = 28)

Total (n = 56)

Ageyears

49.86 ± 6.65

50.93 ± 6.47

50.39 ± 6.53

Heightcm

163.90 ± 7.80

164.10 ± 9.80

164.00 ± 8.80

Body weightkg

73.50 ± 7.44

72.61 ± 8.74

73.06 ± 8.06

Body mass index

kg/m 227.31 ± 1.2526.93 ± 1.41

27.12 ± 1.33

Total fat areacm 2365.02 ± 62.89

352.13 ± 53.60

358.57 ± 58.26

Subcutaneous fat areacm 2234.45 ± 57.74

233.75 ± 66.91

234.10 ± 61.92

Visceral fat areacm 2130.56 ± 38.68

118.38 ± 41.26

124.47 ± 40.10

White blood cells/μL

5,789.30 ± 1,385.20

5,635.70 ± 1,237.40

5,712.50 ± 1,303.70

Red blood cells

10 4 /μL

472.10 ± 38.70

480.70 ± 37.10

476.40 ± 37.80

Hemaglobin

g/dL

14.26 ± 1.45

14.24 ± 1.87

14.25 ± 1.66

Hematocrit%42.55 ± 3.66

42.58 ± 4.37

42.57 ± 3.99

Triglycerides

mg/dL

128.80 ± 58.10

122.90 ± 51.60

125.90 ± 54.50

LDLmg/dL

157.20 ± 37.00

150.60 ± 38.00

153.90 ± 37.30

HDLmg/dL

58.30 ± 11.40

61.10 ± 13.50

59.70 ± 12.50

Free T 4

ng/dL

1.15 ± 0.15

1.22 ± 0.15

1.18 ± 0.16

Free T 3pg/mL

3.28 ± 0.26

3.34 ± 0.28

3.31 ± 0.27

Urinary iodine

μg/L

453.20 ± 498.00

351.70 ± 312.10

402.50 ± 414.90

Urinary iodine corrected for creatinine

μg/g Cre391.10 ± 758.30

224.00 ± 171.10

307.50 ± 551.20

Total free iodine

μg/day530.20 ± 1,144.90

278.80 ± 202.90

404.50 ± 824.50

Data are expressed as mean ± standard error.
IE, iodine-enriched egg; OE, ordinary egg; HDL, high-density lipoprotein cholesterol;
LDL, low-density lipoprotein cholesterol; T3, triiodothyronine; T4, thyroxine.

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Table 3. The characteristics of participants who ingested iodine-enriched egg and ordinary egg for 12 weeks

Baseline
Ageyears

Heightcm

Body weightkg

Body mass indexkg/m 2Total fat area

cm 2

Subcutaneous fat area

cm 2

Visceral fat areacm 2

White blood cells/μL

Red blood cells

10 4/μL

Hemaglobin

g/dL

Hematocrit%Total cholesterol

mg/dL

Triglycerides

mg/dL

LDL

mg/dL

HDL

mg/dL

Free T 4

ng/dL

Free T3

pg/mL

Urinary iodine

μg/L

Urinary iodine
corrected
for creatinine

μg/g Cre

Total urinary idoine

μg/day49.86 ± 6.65-±28

163.90 ± 7.80-±28

73.50 ± 7.44

IE

28

IE

OE
OE
IE

OE
IE

OE
IE

OE
IE

OE
IE

OE
IE

OE
IEOE
IE

OE
IE

OE
IE

OE
IE

OE
IE

OE
IE

OE
IE

OE
IE

OE
IE

OE
IE

OE
IE

OE

week 1228282828
28

50.93 ± 6.47

164.10 ± 9.80-±-±-----

27.40 ± 1.46

0.40

26.93 ± 1.41

26.83 ± 1.45

28

365.02 ± 62.89

355.02 ± 57.24

28

234.45 ± 57.74

235.62 ± 57.19

28

130.56 ± 38.68

119.40 ± 37.66

285,789.30 ± 1,385.20

5,725.00 ± 1,523.80

28472.10 ± 38.70

469.60 ± 34.00

28282828

233.75 ± 66.91

118.38 ± 41.26

5,635.70 ± 1,237.40

347.77 ± 59.38
231.41 ± 68.80

116.36 ± 41.69

5,614.30 ± 1,331.00

28

480.70 ± 37.10

480.50 ± 38.50

28

14.24 ± 1.87

14.09 ± 1.92

28
28
28

14.26 ± 1.45

42.55 ± 3.66

42.58 ± 4.37

14.06 ± 1.57

42.55 ± 3.89

42.54 ± 4.62

28232.20 ± 40.20

235.30 ± 38.10

28

128.80 ± 58.10

146.10 ± 128.30

28157.20 ± 37.00

28

227.50 ± 41.50

227.00 ± 38.50

122.90 ± 51.60

123.30 ± 70.40

28

150.60 ± 38.00

144.10 ± 34.90

28

61.10 ± 13.50

63.50 ± 14.90

1.22 ± 0.15

1.23 ± 0.1728282828

58.30 ± 11.40
1.15 ± 0.1528

3.28 ± 0.26

28453.20 ± 498.00

28391.10 ± 758.30

28

3.34 ± 0.28

155.40 ± 37.90

57.60 ± 11.40
1.19 ± 0.17

3.29 ± 0.35

3.28 ± 0.28

971.40 ± 1,351.20

351.70 ± 312.10

448.20 ± 686.00

28224.00 ± 171.10

278.30 ± 419.00

28278.80 ± 202.90

2828

530.20 ± 1,144.90

Data are expressed as mean ± standard error.
1 P-values for comparing baseline and week 12 values in the IE and OE groups.
2 P-values for comparing the 12-week overall change between the IE and OE groups.
3 P-values for comparing the 12-week percent change between the IE and OE groups.
IE, iodine-enriched egg; OE, ordinary egg; HDL, high-density lipoprotein cholesterol;
LDL, low-density lipoprotein cholesterol; T 3, triiodothyronine; T 4, thyroxine.

_ 175 _-0.41

72.36 ± 8.44

352.13 ± 53.60-73.73 ± 7.68

72.61 ± 8.74

27.31 ± 1.25

1698.20 ± 882.70

899.30 ± 1,328.20
349.60 ± 500.3

0.25
0.24
0.04
0.30
0.76
0.35
0.00
0.550.77
0.93
0.58
0.95
0.17
0.21
0.99
0.89
0.55
0.91
0.50
0.98
0.76
0.13
0.65
0.13
0.12
0.56
0.84
0.29
0.05
0.46
0.20
0.43
0.30
0.41

P-values

23----

0.17

0.21

0.16

0.17

0.36

0.53

0.44

0.30

0.05

0.03

0.89

0.76

0.70

0.79

0.80

0.80

0.94

0.88

0.60

0.60

0.55

0.46

0.51

0.49

0.15

0.18

0.59

0.58

0.37

0.43

0.15

0.01

0.30

0.01

0.41

0.01

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