Glycative Stress Research
Online edition : ISSN 2188-3610
Print edition : ISSN 2188-3602
Received : November 14, 2019
Accepted : January 15, 2020
Published online : March 31, 2020
doi:10.24659/gsr.7.1_29

Original article

Effects of ostrich meat intake on amino acid metabolism and growth hormone
secretion: A comparative clinical study.
Mari Ogura 1), Yuji Morita 1, 2), Wakako Takabe 1), Masayuki Yagi 1), Fuka Okuda 1), Misato Kon 1),
Kenichi Asada 2), Tetsuro Urata 2), Tomoko Tsuji 3), Yoshiko Kawaguchi 3), Yoshikazu Yonei 1)
1) Anti-Aging Medical Research Center and Glycative Stress Research Center,
Faculty of Life and Medical Sciences, Doshisha University, Kyoto, Japan
2) Urata Clinic/SQOL Kanazawa, Kanazawa, Ishikawa, Japan3) Yoshinoya Holdings Co.,Ltd, Tokyo, Japan

Abstract

Objective: We investigated the effects of the intake of ostrich meat (OM), which is characterized by high protein and low fat,on the body, focusing on protein and amino acid metabolism and growth hormone (GH) secretion.
Methods: Plasma amino acid levels, growth hormone (GH) secretion after exercise and autonomic nervous function (device
used: VM500 [Fatigue Science Laboratory Inc.]) were measured in 12 healthy subjects (33.3 ± 6.9 years old, BMI 21.6 ± 1.6)
after ingestion of the test food (OM) or control food for one week each.
Results: A significant increase in the blood levels of branched-chain amino acids (BCAAs), lysine and histidine, and anincrease in those for 1-methylhistidine and 3-methylhistidine, which are the indicators of muscle protein breakdown, wereobserved after the intake of OM, suggesting that protein metabolism in the muscles was activated. Subclass analysis excluding
cases with high GH before exercise load showed a significant increase in GH secretion after a walking exercise (30 min) only
after the intake of OM. The autonomic nervous function test did not reveal any significant findings. There were no OM-related
adverse events during the study.
Conclusion: OM is a low-fat meat containing physiologically significant amino acids in large quantities, and it wassuggested that OM could be safe and suitable for a protein and amino acid supplement.

KEY WORDS: ostrich meat, amino acids, branched-chain amino acid (BCAA), growth hormone, anti-fatigue

Introduction

In recent years, lifestyle-related diseases such as visceralobesity, metabolic syndrome, dyslipidemia, fatty liver, andtype 2 diabetes are increasing. These diseases are often
accompanied by postprandial hyperglycemia (glycemic
spikes), hypertriglyceridemia, and high LDL-cholesterol,
resulting in a high glycative stress condition due to the increaseof aldehydes derived from sugars and lipids. Glycative stressinduces structural changes in the body’s constituent proteinsand functional proteins by highly reactive aldehyde groups,
promotes the progression of arteriosclerosis, becomes a risk
factor for cerebral and cardiovascular events, and is also
closely related to the onset and progression of dementia.
The causes of the increase in glycative stress-associateddiseases include decreased physical activity and increased
caloric intake. However, qualitative changes in nutrition
rather than quantitative changes in the caloric intake ofJapanese people are a more serious problem. Trends ofeating habits in recent years show that for carbohydrates, rice

Contact Address: Professor Yoshikazu Yonei, MD, PhD
Anti-Aging Medical Research Center, Graduate School of Life andMedical Sciences, Doshisha University
1-3, Tatara Miyakodani, Kyotanabe, Kyoto, 610-0394 Japan

Phone/ Fax: + 81-774-65-6394 Email: yyonei@mail.doshisha.ac.jp
Co-authors; Mari O, m-ogura@po.kbu.ac.jp ; Yuji M, ymorita707@yahoo.co.jp ;Takabe W, wtakabe@mail.doshisha.ac.jp ; Yagi M, yagi@yonei-labo.com ;Fuka O, ctuc2017@mail4.doshisha.ac.jp ; Misato K, ctuc2013@mail4.doshisha.ac.jp ;Kenichi A, asada@hospy.jp ; Tetsuro U, tetsuro.u@hospy.jp ;Tomoko T, t.tsuji@ysn.yoshinoya.com ; Yoshiko K, y.kawaguchi@ysn.yoshinoya.com_ 29 _

Glycative Stress Research 2020; 7 (1) : 29- 41(c) Society for Glycative Stress ResearchEffects of Ostrich Meat Intake on Amino Acid and Growth Hormone

consumption has decreased, and for proteins, consumption ofanimal meat has increased rather than fish meat, suggestingthat there is a slight increase in fat intake 1). Dietary fibers
have decreased with a lower intake of vegetables and fruitsin the diet. As one of the methods to overcome the problems
in terms of diet quality, we focused our attention on ostrich
meat, which is a source of good quality protein with less fat.
An adult male ostrich (Struthio camelus) is 2 to meterstall and weighs over 135 kg and is the largest living bird 2-4).
Ostriches have an excellent ability to run on the ground with
their kick force exerting a pressure of 4.8 tons per 100 cm 2.
Ostriches are sometimes considered to be omnivorous.
However, an ostrich can be defined as a herbivore based on
its intestine, which is longer than other birds, where the fiberin the grass is fermented just like in horses and rabbits andused as an energy source. Stones swallowed are used as a
bezoar to grind the food that has been consumed in the gizzard.
Ostrich meat is rich in iron, dark red and has a crunchy texture.
The meat is widely recognized as healthy meat because of
its low fat content and rich L-carnitine level 5, 6). The meatis also characterized by abundant amino acids with a sweet
taste, such as alanine and glycine, compared to other meats.
A repeated measurement study was used to verify
the physical changes, especially post-intake amino acidmetabolism, growth hormone secretion during exercise load,and degree of fatigue, after ostrich meat (test food) ingestion
with the values after control food intake as control.

MethodSubjects

The changes in growth hormone secretion and blood
amino acid levels in 12 healthy men and women between 25
and 45 years old belonging or related to Urata Clinic/Sqol
Kanazawa, after the intake of processed food (smoked ham,boiled in water) using ostrich meat (OM) as a test food were
investigated with those after control food was taken as acontrol.
After the “research using human subjects” was approveda)a)by the ethics review committee of the Society for Glycative
Stress Research, a briefing on the study was held at Urata
Clinic/Sqol Kanazawa (Kanazawa City, Ishikawa) and 12
subjects who had given prior written consent to participate
in this study and were not in conflict with the following
exclusion criteria, were included as subjects:(1) Subjects currently suffering from an illness andreceiving medical treatment(2) Subjects with a history of or now suffering from severe
disease of liver, kidney, heart, lungs and blood(3) Subjects with severe anemia(4) Subjects who are at risk of developing an allergic
reaction to the test food, or other foods or drugs(5) Subjects who regularly consume high protein diet(6) Female subjects who are pregnant, lactating or who
might be pregnant(7) Subjects who are currently participating in otherhuman clinical trials, and those who have participatedin other human clinical trials within the past 3 months
At the case review meeting after the completion ofthis study, all 12 subjects (33.3 ± 6.86 years old) who were
included in this study were considered for analysis.

Study Design
The test food was smoked ham or meat boiled in water
prepared using OM provided by Yoshinoya Holdings Co.,
Ltd. (Chuo-ku, Tokyo, Japan) (Fig. 1). Tables 1 and 2 show
the nutritional ingredients and amino acid content of OM.
The experiment schedule is shown in Fig. 2. First, thesubjects were requested to consume 100 g of the test food
(OM boiled in water) as breakfast on the first day of thestudy. At that time, they were allowed to consume waterand steamed rice along with the test food. Table 3 shows
the nutritional composition per serving of the test food andcontrol food. From the time of intake until the end of thetest on that day, the subjects were allowed to consume only
water. Anthropometric measurements, background surveys
and walking exercise with an intensity of about 3 METS
were performed when the subjects visited the test facility(Visit -1). Walking conditions were the same as previouslyb)b)Fig. 1. Test food (ostrich meat: OM).
a) Smoked ham. b) Boiled in water.

_ 30 _Glycative Stress Research

Table 1. Nutritional composition.

Table 2. Amino acid composition.

Nutritional values per 100 g ostrich meat

Amino acid content per 100 g ostrich meat

EnergyCarbohydrate
AshProteinFat
Total fatty acid
Saturated fatty acid
Monounsaturated fatty acid
Polyunsaturated fatty acid

103
0.0
1.1
22.8
1.3
1.45
0.45
0.59
0.41

kcal
g
g
g
g
g
g
g
g

Vitamins
Vitamin A
Vitamin B1 (thiamine)
Vitamin B2 (riboflavin)
Vitamin B3 (niacin)
Vitamin B6
Follic acid
Vitamin B12
Vitamin C
Vitamin E

0.0
0.18
0.27
4.38
0.48
7. 00
461
0.0
0.24

μg
mg
mg
mg
mg
μg
μg
mg
mg

Day 0 Day 1

Day 7

Visit 1

Day 14

Visit 2Visit 37 days7 daysTest food+ Steamed rice

Control food+ Steamed riceFig. 2. Test schedule.
Table 3. The nutrient composition of control and test food.

Fig. 2
Water (g)Energy (kcal)
Protein (g)Carbohydrate (g)Fat (g)Sodium (mg)

1.32
1.84
0.54
0.84
0.72
1.66
0.93
0.54
0.96
1.20
0.91
0.79
3.05
0.84
0.95
1.84
0.28
0.24
0.04

Arginine
LysineHistidine
Phenylalanine
Tyrosine
LeucineIsoleucine
Methionine
ValineAlanineGlycineProlineGlutamic acid
SerineThreonine
Aspartic acid
Tryptophan
CystineFree glutamine

Control food

Test foodCup soup

Boiled in water

Smoked ham

136
2.5
22
4.4
659

61.2
102
21.9
0
1.6
136

47.7
96
18. 5
0.1
2. 4
323

_ 31 _

g
g
g
g
g
g
g
g
g
g
g
g
g
g
g
g
g
g
g

Effects of Ostrich Meat Intake on Amino Acid and Growth Hormone

reported 7), and the subjects walked for 30-minutes on atreadmill (Life Fitness Discover Treadmill SE3; Brunswick
Corporation, Illinois, USA) set at a speed of 4. 5 km/h. A
glucose load (40 g of glucose) was administered 75 minutes
before the walking exercise to temporarily suppress GH
secretion, which is the primary endpoint. Subsequently,
15 minutes before the walking exercise, GH, amino acids
analysis, triglyceride (TG), plasma glucose (PG) andimmunoreactive insulin (IRI) were measured by hematology
and blood biochemistry tests and autonomic nervous function
was evaluated using a VM500 device (Fatigue Science
Laboratory, Yodogawa-ku, Osaka, Japan). A second sampleof blood was drawn after the walking exercise, and change inblood tests and autonomic nervous function before and after
walking were evaluated.
The subjects, then, consumed the test food for a total of
6 days for breakfast, with 100 g intake of ham OM (test food)for 3 days, and 100 g intake of OM boiled in water (test food)for 3 days (subjects could decide the order of intake). On day
7, the subjects visited the test facility (Visit-2), a walking
exercise with an intensity of about 3 METS was performedfor 30 minutes. A glucose load was administered 75 minutes
before the walking exercise, blood test and autonomic nervous
function evaluation were performed 15 minutes before thewalking exercise, and a blood test was performed again after
the walking exercise.
Subsequently, the subjects consumed control food(Jikkuri Kotokoto Kongari Pan Corn Potage; Pokka Sapporo
Food & Beverage Ltd., Nagoya, Aichi, Japan) that was set
as the control for breakfast starting one week before thethird examination day (consumption of water and steamed
rice along with the control food was allowed). The tests
performed on the third examination day (Visit-3) were thesame as those on the second examination day. The study
period was from April 2019 to May 2019.

nerve (low frequency (LF)) and parasympathetic nerve (highfrequency (HF)) components are extracted from the form of
the pulse wave and expressed as the autonomic nerve balance(LF/HF), and an activity index of the autonomic nerves isexpressed as CCVTP (coefficient of component variancetotal power).
The average of the calculated values for each heartbeat was used as the LF/HF. It has been reported that when aperson is tired, the tension of the sympathetic nervous systemincreases and the activity of the parasympathetic nervous
system decreases. As a result, a balance value of less than
2.0 is evaluated as “Standard value,” between 2.0 and 5.0 as“Warning,” and 5.0 or more as “Caution needed.”
CCVTP was the average value of the indices derived
from the sum of LF and HF over the entire duration of themeasurement. This value is high in healthy subjects andlow in those with fatigue and stress. In healthy persons, thenumerical value is high while they are young and gradually
decrease with aging. The result was matched with the
population information of CCVTP to determine the age at
which the measured value matches, and was expressed as
autonomic nervous function age.

Statistical Analysis
Statistical analysis software SPSS (IBM Japan, Chuoku, Tokyo, Japan) was used for statistical analysis and apaired t-test was performed for comparison over time.
One-way analysis of variance and Tukey's range test were
performed for differences between groups. A risk rate of lessthan 5% was considered a significant difference. No outliersin particular were set. However, when data could not be
obtained due to problems during testing or a serious problem
occurred in the reliability of the data, such values wereconsidered as missing values and substitute values were notused.

Ethical Review

Evaluation items

Anthropometric measurements
Height, weight, body fat percentage, body mass index(BMI), systolic and diastolic blood pressure, and pulse rate
were measured. The body composition test was performed
using a body composition analyzer (InBody770; InBody
Japan, Koto-ku, Tokyo, Japan).

Blood chemistry examination
Peripheral blood tests and biochemical tests were
performed using the blood samples. The evaluation items
for the examination were GH, amino acid analysis, TG,
PG and IRI. The measurements during the tests using theblood samples were performed by Alp Co., Ltd. (Kanazawa,
Ishikawa, Japan).

Autonomic nervous function evaluation

This study was conducted in compliance with theHelsinki Declaration (revised at the 2013 WMA General
Assembly in Fortaleza) and the Ethical Guidelines for
Medical and Health Research Involving Human Subjects(Notification of the Ministry of Education, Culture, Sports,
Science and Technology Ministry of Health, Labor andWelfare). This study was approved by holding a “ethics
committee meeting for 'Research on Human Subjects' at
the Society for Glycative Stress Research” (Shinjuku-ku,
Tokyo, Japan), where deliberation on the ethics and validityof the study was conducted. (Glycative Stress Research 2019
No. 001). The clinical trial for this study was pre-registered(UMIN #000035656).

Results

General background

Vital monitor VM500 (Fatigue Science Laboratory,
Yodogawa-ku, Osaka, Japan) was used to measure the balance
and amount of activity (autonomic nervous function age) of
the autonomic nervous system 8, 9). In this method, sympathetic

The 12 subjects analyzed were 33.3 ± 6.9 years old,
169.7 ± 7.6 cm tall, weighing 62.6 ± 8.5 kg, and having a BMI
of 21.6 ± 1.6 (Table 4 ).

_ 32 _Glycative Stress ResearchAmino acid analysis

Table 4. Anthropometry.
Average
Age

33.3

±

6.86

Height

cm

169.7

±

7.59

Weight

kg

62.6

±

8.51

Body fat %

21.5

±

5.57

-

21.6

±

1.55

BMI

In the blood amino acid analysis performed during
each visit ( Table 7 ), amino acid that showed significant
difference between groups on Visit-2 and Visit-3 werevaline ( p < 0.05), methionine ( p < 0.05), isoleucine (p <0.01), leucine ( p < 0.01), tyrosine ( p < 0.05), β-alanine(p < 0.05), 1-methylhistidine (p < 0.01), lysine (p < 0.05),
and 3-methylhistidine (p < 0.01), and all the values during
Visit-2 were significantly higher than those during Visit-3.
1-methylhistidine and 3-methylhistidine were significantly
higher during Visit-1 than during Visit-3 (both p < 0.01,
Fig. 5 ). These amino acids remained high during ostrich
meat intake, but showed a significant decrease one week
after discontinuation.

SDn = 12. BMI, body mass index; SD, standard deviation.

Growth Hormone (GH)GH on Visit-1 (day 1 of OM intake) was 0.86 ± 1.09 ng/
mL and 3.20 ± 3.69 ng/mL before and after the walking
exercise. On Visit-2 (day 7 of OM intake), it was 1.23 ± 1.66
ng/mL and 2.45 ± 2.01 ng/mL before and after the walking
exercise On Visit-3 (day 7 of control intake), it was 1.13
± 2.46 ng/mL and 1.71 ± 1.80 ng/mL before and after thewalking exercise (Table 5). The changes in blood GH levels
between before and after exercise on each visit are shown in
Fig. 3. There was no significant difference in the GH change
rate between the groups in Visit-1, Visit-2 and Visit-3.
During the verification of individual data for each visit,some subjects were found to have a high GH value before
exercise. Hence, subclass analysis was performed with thepre-exercise cutoff value set at 4.00 ng/mL or more ( Fig. 4 ).
During Visit-2, GH had increased significantly after exercise( p = 0.018, Table 6 ). On the other hand, no significant
increase in GH was observed during Visit-1 and Visit-3.

Triglyceride (TG)
Serum TG was 88.3 ± 34.9 mg/dL before exercise and71.2 ± 25.4 mg/dL after exercise during Visit-1, 100.2 ± 77.2
mg/dL before exercise and 65.2 ± 18.3 mg/dL after exercise
during Visit-2, and 78.1 ± 26.5 mg/dL before exercise and74.3 ± 36.6 mg/dL after exercise during Visit -3 (Table 8 ).
There was no significant difference in the TG change rate
between the groups during Visit-1, Visit-2, and Visit-3.

Blood glucose (PG)
PG was 114.0 ± 35.5 mg/dL before exercise and 93.1 ±15.9 mg/dL after exercise during Visit-1, 112.2 ± 35.3 mg/dL
before exercise and 88.8 ± 14.8 mg/dL after exercise during
Visit-2, and 108.3 ± 26.7 mg/dL before exercise and 92.8
± 18.3 mg/dL after exercise during Visit-3 ( Table 8 ). There
was no significant difference in the PG change rate between
the groups during Visit-1, Visit-2, and Visit-3.

Table 5. Serum GH
Before walking

After walking

p value

Inter- group analysis(vs.Visit-3)

Visit -1 (OM 1 day)ng/mL

0.86 ± 1.09

3.20 ± 3.69

0.056

0.481

Visit -2 (OM 7 days)

ng/mL

1.23 ± 1.66

2.45 ± 2.01

0.134

0.382

Visit -3 (Control 7 days)

ng/mL

1.13 ± 2.46

1.71 ± 1.80

0.538

Data are expressed as mean ± SD, paired t test, n = 12. OM, ostrich meat; Control, control meat; GH, growth hormone; SD, standard deviation. Statistical analysis
by Turkey test.

Table 6. Serum GH: Subclass analysis.
Before walking

After walking

p value

Visit -1 (OM 1 day)ng/mL

0.86 ± 1.09

3.20 ± 3.69

0.056

Visit -2 (OM 7 days)

ng/mL

0.81 ± 0.95

2.62 ± 2.02

0.018

Visit -3 (Control 7 days) ng/mL

0.4 0 ± 0.46

1.39 ± 1.53

0.064

Subclass analysis was conducted by excluding the subjects who’ s GH values exceeded 4.00 ng/mL before walking.
Data are expressed as mean ± SD, paired t test, Visit -1 (n = 12), Visit -2, 3 (n = 11).
OM, ostrich meat; Control, control meat; GH, growth hormone; SD, standard deviation.

_ 33 _

Visit-1
Visit-1

12
12
10
10
8
8
6
6
4
4
2
2
0
0

Before walking
Before walkinga)a)After walking
After walking

b) b)

a)

Before walking
Before walking

After walking
After walkingb)

Visit-3
Visit-3

12
12
10
10
8
8
6
6
4
4
2
2
0
0

80
80
60
60
40
40
20
20
0
0
-20
-20
-40
-40

GH
change(%)
GHchange
(%)

Serum
GH
Serum
GH

Visit-2
Visit-2

12
12
10
10
8
8
6
6
4
4
2
2
0
0

Serum
Serum
GH
GH

Serum
GH
Serum
GH

Effects of Ostrich Meat Intake on Amino Acid and Growth Hormone

Before walking
Before walking

After walking
After walking

c)c)
c)

visit-1
visit-1

visit-2
visit-2

visit-3
visit-3

d)d)
d)

Fig.
Fig. 3. 3
GH secretion: Total analysis.
Fig.
3Exercise-induceda) One day after Test food (OM) intake (Visit-1). b) One week after Test food (OM) intake (Visit-2). c) One week after Control food intake(Visit-3). d) Percent change of serum GH. Results are expressed as mean ± SD. n = 12 at each visit. GH, growth hormone; OM, ostrich
meat; SD, standard deviation.

Visit-3

Visit-2

12

12

10

10

8

8

6

6

4

4

2

2

0

Befor walking

0After walking

Befor walking

After walkingb)a)Fig. a)4. Exercise-induced GH secretion: Subclass analysis.

b)a) One week after Test food (OM) intake (Visit- 2). b) One week after Control food intake (Visit -3). The subjects with high pre-values ofGH exceeding 4.00 ng/mL are excluded in the subclass analysis. *p < 0.05, paired t test, n = 11. GH, growth hormone; OM, ostrich meat.

Fig. 4_ 34 _Glycative Stress Research

Table 7. Amino acid Analysis
Visit -1
(OM 1 day)TaurinePhosphoethanolamine
Aspartic acid
Hydroxyproline
Threonine
SerineAsparagine
Glutamic acid
Glutamine
Sarcosine
α-Aminoadipic acid
ProlineGlycine
AlanineCitrulline
α-Aminobutyric acid
ValineCystine
Methionine
Cystathionine
Isoleucine
LeucineTyrosine
β-Alanine
Phenylalanine
β-Aminoisobutyric acid
Homocystin
γ-Aminobutyric acid
Monoethanolamine
Hydroxylysine
Ornithine
1-Methyl histidine
Histidine
Lysine3-Methyl histidine
Tryptophan
Anserine
Carnosine
Arginine
Alloisoleucine
Fischer’ s ratio

77.23± 9.824.46± 0.84-13.48

157.83132.88

65.83

61.20

512.01-

178.21241.76433.88

23.26
23.59

252.58
30.42
28.14

-

71.00

128.13

66.73
9.79

65.20
2.04
-

9.89

-

129.04
18.11

92.29

223.84

6.20

56.07

-

41.30
-

3.51

Visit -2
(OM 7 days)

± -

76.82

± 9.084.33± 1.28-± 3.1513.56± 27.51156.38± 18.83132.38± 11.59

68.01± 11.93

60.93± 66.17521.92

± -

-

± -

-

± 44.81180.82± 37.76230.84± 2.6924.66± 75.46434.88± 6.1524.98± 36.09266.95± 6.7830.25± 16.68

81.05± 5.19

31.23

± -

-

± 26.07144.36± 1.8810.38± 13.98

69.56± 12.57

66.33± 0.81

1.89

± -

-

± -

-

± 1.839.27± 25.45133.37± 13.79

92.74

± -

-

± 4.6122.93± 55.00

236.96± 9.8956.17± 1.26

6.51

± -

-

± -

-

± 15.4245.28± 0.74

3.59

± -

-

± -

± 4.45± 45.00

Visit -3
(Control 7 days)
73.31± 13.83

4.14± 0.79-10.75

135.09± 19.53

124.66± 17.59

62.93± 11.60± 69.32± ± -± 50.56± 41.97± 80.11± 4.85± 5.9962.83

505.34-168.31

234.48414.98
21.74

22.59

± 61.21204.49± 9.6620.54± 32.26

49.08± 6.28± -± 46.11

32.78
-

98.01

± 12.9454.69± 8.8957.58± 3.43± 0.71
± ± -

7.42

2.08
-

± 1.06

8.67± 39.60

108.90± 13.83

84.95

± -

± 9.52-7.50± 73.64

178.20± 8.8848.31± 1.42
± ± -

4.37
-

± 13.0333.28± 0.63

3.23

± -

-

± -

± 5.52± 24.83± 11.69± 10.09± 17.20± 43.99± ± -± 55.11± 37.25± 47.72± 3.56± 4.92± 39.90± 5.73± 4.60± -± 9.88± 17.86± 14.61± 1.84± 12.07± 0.79± ± -± 1.43± -± 26.23± 4.98± 13.74± 25.78± 1.21± 9.32± ± -± 13.86± -± 0.70n = 12. OM, ostrich meat; Control, control meat; Fischer’ s ratio, the molar ratio of BCAAs (leucine, valine, isoleucine) to aromatic AAs (phenylalanine,tyrosine); BCAAs, branched-chain amino acids; SD, standard deviation.

_ 35 _

Effects of Ostrich Meat Intake on Amino Acid and Growth Hormone

ValineValine400
400

LeucineLeucine ＊＊

＊
＊

300
300
200
200
100
100
0
0

Visit-1
Visit-1

Visit-2
Visit-2

Visit-3
Visit-3a)a)a)Isoleucine
Isoleucine
＊＊
＊＊

120
120
80
80
40
40

Visit-1
Visit-1

Visit-2
Visit-2

Visit-3
Visit-3c)c)c)Lysine

60
60
50
50
40
40
30
30
20
20
10
10
0
0

＊
＊
＊
＊

Visit-1
Visit-1

Visit-2
Visit-2

Visit-3
Visit-3

＊

80

200

60

150

40

100

20

50

0

Visit-1

Visit-2

Visit-3e)e)Visit-1

Visit-2

Visit-3

ff))
1-Methyl-histidine

20

Visit-3
Visit-3

Methionine
Methionine

100

250

30

Visit-2
Visit-2

Tyrosine

＊

300

40

Visit-1
Visit-1d)d)d)Fig. 5
Fig. 5 350

0

＊＊

b)
b)
b)

160
160

0
0

200
200
150
150
100
100
50
50
0
0

＊＊
＊＊

3-Methyl-histidine10_ 36 _

8
6

＊＊
＊＊

g. 5

Fig. 55000Visit-1

Visit-2

Visit-3e)Visit-2

Visit-3Glycative Stress Researchf)1-Methyl-histidine

403-Methyl-histidine

＊＊

＊＊

10

＊＊

＊＊

8

30

6

20

4

10
0

Visit-1

2

Visit-1

Visit-20

Visit-3g)g)Visit-1

Visit-2

Visit-3h)h)β-Alanine

20

＊
15
10
5
0

Visit-1

Visit-2

Visit-3i i))Fig. 5. Changes of plasma amino acid.

a) Valine. b) Leucine. c) Isoleucine. d) Methionine. e) Lysine f ) Tyrosine. g) 1-Methyl-histidine. h) 3-Methyl-histidine. i) β-Alanine.
Results are expressed as mean ± SEM, n = 12. *p < 0.05, **p < 0.01 by Tukey’s test. SEM, standard error mean.

Insulin (IRI)
Serum IRI was 26.4 ± 10.9 μU/mL before exercise and11.0 ± 8.0 μU/mL after exercise during Visit -1, 23. 5 ± 10.0
μU/mL before exercise and 10.7 ± 6.6 μU/mL after exercise
during Visit -2, and 22.2 ± 9. 2 μU/mL before exercise and10.8 ± 6.8 μU/mL after exercise during Visit - 3. In eachgroup, insulin decreased significantly before and after
exercise (both p < 0.01, Table 8 ). There was no significant
difference in the IRI change rate between the groups during
Visit -1, Visit -2, and Visit-3.

Autonomic nervous function evaluation
Autonomic nerve balance (LF/HF) was 1.70 ± 1.71 before
exercise and 2.57 ± 2.11 after exercise during Visit-1, 1.01
± 0.63 before exercise and 2.00 ± 1.41 after exercise during
Visit-2, and 1.46 ± 1.17 before exercise and 1.46 ± 0.82 after

exercise during Visit-3. During Visit-2, LF/HF increased
significantly before and after exercise (p = 0.045, Table 9 ).
However, those values were mostly around the “Standard
value (less than 2.0).” There was no significant differencein the LF/HF change rate between the groups during Visit-1,
Visit-2, and Visit-3.
Among the pre-exercise LF/HF values of Visit-1, Visit-2,
and Visit-3, the values during Visit-2 were the lowest.
However, no significant difference was observed between thegroups.
The autonomic nervous function age was 35.6 ± 14.0
years before exercise and 4 0.3 ± 13.4 years after exercise
during Visit-1, 44.4 ± 11.2 years before exercise and 42.5 ±9.2 years after exercise during Visit-2, and 41.7 ± 11.4 years
before exercise and 38.2 ± 12.1 years after exercise during
Visit-3. There was no significant difference in the change
rate between the groups during Visit-1, Visit-2, and Visit-3.

_ 37 _

Effects of Ostrich Meat Intake on Amino Acid and Growth Hormone

Table 8. Serum TG, PG and Serum IRI

serum TG

PG

Serum IRI

Before walking

After walking

p value

Visit -1 (OM 1 day)

mg/dL

88.25

± 34.88

71.17± 25.36

0.202

Visit - 2 (OM 7 days)

mg/dL

100.17± 77.2365.17± 18.26

0.158

Visit -3 (Control 7 days)

mg/dL

78.08

± 26.5274.25± 36.56

0.781

Visit -1 (OM 1 day)

mg/dL

114.00± 35.52

93.08± 15.85

0.088

Visit - 2 (OM 7 days)

mg/dL

112.17± 35.3088.75± 14.84

0.055

Visit -3 (Control 7 days)

mg/dL

108.25± 26.72

92.83± 18.30

0.129

Visit -1 (OM 1 day)

μU/mL

26.37

± 10.94

11.03± 7.950.001

Visit -2 (OM 7 days)

μU/mL

23.49

± 10.01

10.65± 6.57

0.002

Visit -3 (Control 7 days)

μU/mL

22.24

± 9.17

10.83± 6.82

0.003

Data are expressed as mean ± SD, paired t test, n = 12. OM, ostrich meat; Control, control meat; TG, triglyceride; PG, plasma glucose; IRI, immunoreactive
insulin; SD, standard deviation.

Table 9. Evaluation of autonomic nervous activity.

Autonomic balance

Autonomic nervous
function age

Before walking

After walking

p value

Visit -1 (OM 1 day)

1.70

± 1.71

2.57± 2.11

0.296

Visit - 2 (OM 7 days)

1.01± 0.632.00± 1.41

0.045

Visit -3 (Control 7 days)

1.46± 1.171.46± 0.82

0.997

Visit -1 (OM 1 day)

year

35.58

± 13.98

40.25± 13.39

0.4 33

Visit - 2 (OM 7 days)

year

44.42

± 11.2242.50± 9.24

0.666

Visit -3 (Control 7 days)

year

41.67

± 11.40

38.17± 12.08

0.492

Data are expressed as mean ± SD, paired t test, n = 12. OM, ostrich meat; Control, control meat; GH, growth hormone; SD, standard deviation.

Safety evaluation
No adverse events or side effects were observed due tothe test food during or after the study period.

Discussion

How ostrich meat became a food source
The murals of ancient Egypt depict ostriches being
raised. After landing in Cape Town, South Africa in 1652,
the Dutch actively captured and slaughtered ostriches, likeother wild birds. Ostrich breeding became active around the17th century and by the 20th century, ostrich feathers, alongwith gold, diamonds and wool, had become South Africa's
principal item of trade. Ostrich breeding had long been alivestock business that was monopolized by South Africa.
However, the ban on the export of eggs and birds from South
Africa was lifted in 1993, and breeding of ostriches as newpoultry source became widespread throughout the world.
Even in Japan, since the late 1990s, ostrich breeding has

become more active with an increase in the number of birds
and establishment of producers’ groups, and the ostrich was
included as an animal subject in the Livestock Infectious
Disease Prevention Act in 2008 10).
Since ostrich meat (OM) is high in protein and low infat, some consumers who are conscious about health started
consuming OM as a substitute for beef in Europe and theUnited States, especially in the European Union (EU)countries, Bovine Spongiform Encephalopathy (BSE) was a
tailwind for OM. The market size based on consumption isestimated to be tens of thousands of tons per year worldwide
and about 100 tons per year in Japan.

Result summary
In this study, blood amino acids, GH secretion anddegree of fatigue (autonomic nervous function) after exercise
load were compared by repeated measurements in 12 healthy
men and women after intake of OM (test food) and control
food. The results showed that blood levels of amino acids
such as branched-chain amino acids (BCAAs) increased
and GH secretion was observed to increase significantly_ 38 _Glycative Stress Research

after exercise load with subclass analysis when OM wasconsumed. The autonomic nervous function test showed nosignificant difference between the groups. No adverse eventswere observed with OM intake.

Branched-chain amino acids (BCAAs)
BCAAs, namely, such as valine, leucine and isoleucine,are amino acids involved in muscle synthesis, and the bloodlevels of which increased after OM intake in this study. Postexercise intake of BCAA activates muscle protein synthesisassociated signaling in human skeletal muscles and suppresses
exercise-induced activation of mechanisms associated withproteolysis 11). The administration of BCAAs suppresses theexercise-induced expression of the mTORC1 inhibitor DDIT4mRNA in skeletal muscles and prevents activation of theubiquitin-proteasome system. Post-exercise consumption of
BCAAs partially suppresses exercise-induced expression ofperoxisome proliferator-activated receptor γ - coactivator 1α
mRNA and activation of ubiquitin-proteasome signaling andsuppresses DDIT4 mRNA expression. On the other hand,
ACC Ser79/222 phosphorylation, an endogenous marker
of AMP-activated protein kinase activity, increases after
exercise regardless of BCAA intake. Key markers of protein
synthesis, such as expression of IGF1 mRNA isoforms or
phosphorylation do not change with or without BCAA intake.
Maintaining skeletal muscles is important for sustaining
daily physical activity and maintaining quality of life.
Protein increases muscle protein synthesis within 1-2 hours
after intake. Muscle protein anabolism associated withprotein intake is caused mainly by leucine, and the rate ofmuscle protein synthesis also increases with an increase in the
blood leucine levels 12). Intake of leucine-enriched essential
amino acid mixture suppresses the exercise-induced elevationof muscle damage markers in the blood, reduces muscle
damage and assists muscle recovery 13).
When electrical stimulation of skeletal muscles and BCAA
intake are used in combination for healthy students, lactic acidlevels after exercise are lower, oxygen consumption is higher,
and delayed myalgia is milder compared to the control group 14).
In the elderly with sarcopenia who are undergoing convalescentrehabilitation, a combination of resistance training and BCAA
intake brings better improvement 15). There are several otherreports on the recovery-promoting effects of the intake
of BCAAs on patients in rehabilitation 16, 17). Since BCAA
levels also decrease after invasive surgeries 18), OM may besuitable as a preoperative and postoperative meal for BCAA
supplementation.

Association with GH secretion
Since basic amino acids such as lysine and arginine havea GH secretion effect, intravenous administration tests ofthese amino acids are performed to diagnose GH secretion
deficiency 19). These amino acids also affect the gastrointestinal
motility, while lysine promotes gastrointestinal motility, but
arginine suppresses gastrointestinal motility.
In clinical studies, it has been reported that a single intake
of a supplement containing lysine and arginine also increases
GH secretion after exercise load (30-minute ergometer) 20).
In this study, there was a significant increase in lysine bloodlevels as well as GH secretion during subclass analysis after

OM intake, suggesting that the potential of GH secretion may
have increased after OM intake.

Muscle metabolism and 3-methylhistidine
In the body, proteins maintain a nitrogen balance state
by repeating synthesis and decomposition. Skeletal muscle
tissues account for a large percentage of body proteins andhave a high metabolic rate. 3-Methylhistidine is a constituent
amino acid of myosin and actin. 3-methylhistidine producedby the decomposition of muscle protein is excreted in urine
without being metabolized 21). By measuring the amount of
3-methylhistidine excreted in the urine, the decomposition
rate of actin in the muscles can be estimated. The synthesis of
3-methylhistidine in muscle cells is performed by introducing
the methyl group of methionine into histidine after thetranslation of the polypeptide chain of myosin and actin 22, 23).
As protein intake in the diet increases, fluctuations inenzyme activity increase 24, 25), plasma protein and proteins in
the liver, kidney, and small intestinal mucosa 25) increase, andprotein metabolism in the muscles increase 21). It is consideredthat the rate of proteolysis of skeletal muscles increases asmuscle metabolic activity increases 27). In this study, sinceamino acids, such as BCAAs, which assist muscle synthesis,
increased with the intake of OM, indicating that protein
metabolism in the skeletal muscles was activated, it canbe interpreted that 3-methylhistidine, which is an index ofmuscle protein decomposition, increased.

Fatigue and amino acids
A close relationship exists between amino acids
and fatigue. BCAA concentration in the blood decreases
during acute muscle fatigue due to exercise load 28). Valine
supplementation during exercise is effective in maintaining
hepatic glycogen and blood glucose, increases spontaneous
activity after exercise, and contributes to reducing fatigue
in animal experiments using rats 29). It has been reported ina randomized, double-blind, placebo-controlled, crossoverstudy that a 4-week intake of food containing S-allyl cysteine
reduces fatigue 30). Even clinical studies have shown that intakeof leucine-enriched essential amino acid mixture assists in therecovery from muscle fatigue 13). The amino acid compositionof OM is rich in leucine and may contribute to recovery frommuscle fatigue.
In this study, a reduction in fatigue could be expectedby OM intake. However, a significant difference was notdetected between the groups in autonomic nervous function
evaluation. The autonomic nerve balance (LF/HF values)
before exercise load was 1.70 ± 1.71 during Visit-1, 1.01 ±0.63 during Visit-2, and 1.46 ± 1.17 during Visit-3, and thepost- OM intake values were the lowest. This could be anindicator of a potential fatigue-reducing effect of OM intake.

SafetyThe investigation of radioactive contamination following
the accident at the Fukushima Daiichi Nuclear Power
Station has been reported 31). As a result of inspection using
ostrich samples collected from December 2011 to May 2012,129m Te and 110mAg were not detected in any of the inspected
samples. Low levels of 137Cs (19.2 ± 11.7 Bq/kg) and 137Cs_ 39 _

Effects of Ostrich Meat Intake on Amino Acid and Growth Hormone(18.3 ± 11.3 Bq/kg) were detected in the skeletal muscles offive ostriches bred in the Kanto region, 150 km away fromthe nuclear power plant while no radioactive Cs was detectedin the ostriches bred before the accident, and it is presumed
that the cause of the contamination was a transient event
caused by the radioactive material carried from the nuclear
power plant. Radiation contamination has not been reported
in ostriches hatched after 2013. Since ostrich meat is rich inhigh quality unsaturated fatty acids, which are oxidized due
to long-term storage, the meat needs to be stored carefully 4).

Conclusion
The result of comparative study of blood amino acids,
GH secretion after exercise load and autonomic nervous
function after intake of test food (OM) and control food for
one week each on 12 healthy subjects showed a significant
increase in blood amino acid levels, such as BCAAs, lysine

Referenceand histidine, and a significant increase in GH secretion after
exercise load with subclass analysis, after OM intake. OM
is low-fat animal meat containing good quality amino acidsin large quantities, and it was suggested that OM is safe andsuitable as a protein and amino acid supplement.

Conflict of Interest
This research received support from Yoshinoya
Holdings.

Acknowledgment
This study was presented at the Meeting for ClinicalResearch and Nutrition Therapy of Japanese Society of AntiAging Medicine on November 10, 2019, Tokyo, Japan.

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_ 41 _