Yonago Acta medica 2002;45:103–111

Dioxins and Fatty Acids in Breast Milk of Primiparas in Yonago
District, Tottori Prefecture, Japan
Mari Sampei, Koji Kimura*, Kousaku Ohno†, Shiro Ikawa‡ and Kazuo
Yamada§Department of Women’s and Children’s Family Nursing, School of Health Science, Tottori University Faculty of Medicine, *Radioisotope Research Center, Tottori University, †Department ofChild Neurology, Institute of Neurological Sciences, ‡Division of Clinical Laboratory Medicine
and §Division of Medical Biochemistry, Department of Pathophysiological and Therapeutic
Science, School of Medicine, Tottori University Faculty of Medicine, Yonago 683-8503 JapanWe analyzed the concentrations of polychlorinated dibenzo-p-dioxins (PCDDs) anddibenzofurans (PCDFs) in breast milk collected 1 week after childbirth from 8
primiparas in Yonago district, Tottori Prefecture, and investigated the relationshipbetween PCDDs or PCDFs and fatty acids in concentration, and the relationship between
dioxin concentration and kind of daily foods. The mean total content of dioxins (PCDDs
and PCDFs) was 0.48 pg-toxic equivalent (TEQ)/g (range 0.12–1.04 pg-TEQ/g) in breast
milk, and 16.7 pg-TEQ/g-fat (range 9.6–32.7 pg-TEQ/g-fat) in total lipids of breast
milk. The 8 primiparas showed a low mean dioxin concentration: the levels werelower in 6 of them and higher in 2 of them than in primiparas living in other cities inJapan. For 1 of the 2 mothers, the reason for the high level was thought to be her poor
intake of vegetables in the diet. The total dioxin content was well correlated with thetotal lipid content ranging from 1% to 3%. Fatty acids with C16:0 and C18:1 dominatedthose with C12:0, C14:0, C16:1, C18: 2 and C18:0, which were commonly detected. The amountof fatty acids with C10:0, C20:1, C20:2, C20:3, C20:4, C22:5 and C22:6 was small. Gas chromatograms of these fatty acids generally showed similar distributions in breast milk of the 8primiparas. The contents of fatty acids ranged from 17.1 to 31.3 mg/g (average 24.0mg/g) in bulk breast milk. No clear correlation was found in concentration between
PCDDs or PCDFs and specific fatty acids in breast milk.
Key words: breast milk; fatty acid; food life; lipid; polychlorinated dibenzo-p-dioxin; polychlorinated dibenzofuran; primipara

Polychlorinated dibenzo-p-dioxins (PCDDs)
and polychlorinated dibenzofurans (PCDFs),
which are reported as “endocrine disruptors”,
have a severe toxicity which acts as internal secretions causing sexual disturbances (Schuler etal., 1997; Kayama, 1998; Matsuo, 1998). The
presence of dioxins (PCDDs and PCDFs) inbreast milk has increased the advocation of
women’s and children’s health (Sakai, 1998;
Watanabe et al., 1999; LaKind et al., 2001). In

recent years, dioxins in breast milk have been
detected many times higher than the normal
concentration in breast milk, and the influenceon babies and infants is a serious problem(Ministry of Health and Welfare, 1998). We
wanted to clarify the qualitative and quantitative relationship between the concentrations of
dioxins and fatty acids, and the habitual intake
of daily food. The exposure to dioxins has been
decreasing as shown by a downward trend ofAbbreviations: GC, gas chromatography; MS, mass spectrometry, PCDD, polychlorinated dibenzo-p-dioxin;
PCDF, polychlorinated dibenzofuran; TEF, toxic equivalency factor; TEQ, toxic equivalent103

M. Sampei et al.

Table 1. Primiparas’ data, dietary life and living environments

Sample Age Height Weightnumber (year) (cm)
(kg)
1
2
3
4
5
6
7
8

30
25
27
31
33
27
27
30

155
157
160
158
161
150
152
150

60.0
53.5
71.3
61.0
56.2
63.0
64.5
59.8

Status ofmilk
secretion

Lipid content
in breast milk
(% )

Good
NormalGood
Good
Not so good
NormalGood
Very good

2.49
2.32
1.25
3.03
3.26
3.54
4.31
2.47

Meal*
Vegetable Meet
–
2+
2+
2+
3+
2+
2+
3+

2+
2+
2+
2+
2+
2+
3+
2+

Fish

Residence

2+
2+
2+
2+
+
2+
2+
2+

Yonago city
Yonago city
Yonago city
Saihaku-county
Yonago city
Tohaku-county
Saihaku-county
Tohaku-county* 3+, often; 2+, common; +, rare; –, little.

dioxins both in human breast milk and serum
lipids during the last 20 to 30 years (Kiviranta etal., 1999; Ministry of Health, Labour and Welfare of Japan, 2000; Przyrembel et al., 2000);
however, the level of dioxin content has notbeen made clear in smaller cities, which we
think should be made evident. In the San-in
region of Japan, except for Shimane Prefecture,breast milk has still not been analyzed fordioxins. Little information is available forallowing a good assessment of breast milk in
mothers especially in Tottori Prefecture. A
solution to the actual situation in Yonago district has long been awaited in order to help
expecting mothers who visit in Tottori University Hospital learn more about breastfeeding.
For this study, we analyzed and estimatedthe contents of PCDDs, PCDFs and lipids inbreast milk of primiparas (mothers of firstborn
children) who live in Yonago district, and discussed the quantitative relationships among
them.

Materials and Methods

Breast milk samples
Breast milk was obtained from 8 primiparas ingood health who were hospitalized at Tottori
University Hospital and had a normal delivery.
Samples were collected after suckling the baby

twice a day between day 3 and day 7. The collected quantity was 10 to 20 mL each, totaling
approximately 100 mL. The specimen was thenstored in a refrigerator at –80˚C until analysis.
Age and occupation of the primiparas were
not fixed and control of meals was not performed. However, they ate hospital food during
their hospitalization. Table 1 shows the conditions of the primiparas and other information.
The 8 primiparas well understood the purpose of the study as we explained it to them, andtheir consent to publish the data was obtained.

GC/MS conditions for dioxin analysis
A high-resolution gas chromatograph/highresolution mass spectrometer (double-focusingtype) is normally used for dioxin analysis. Gas
chromatography/mass spectrometry (GC/MS)
operating conditions recommended for dioxin
analysis by the guideline of the Ministry of
Health, Labour and Welfare of Japan are i) the
resolution must be above 10,000 and ii) everym/z set up must be less than 4 decimal points(Ministry of Health and Welfare of Japan, 1997;
Environment Agency of Japan Dioxin Risk
Evaluation Committee, 1998a). The analysis of
dioxins was done at the Hiroshima Environment and Health Association.

104

Dioxins and fatty acids in breast milk

Table 2. Concentration of PCDDs and PCDFs in breast milk
Samplenumber
1
2
3
4
5
6
7
8

PCDD/total milk*(pg/g) (pg-TEQ/g)

PCDF/total milk*
PCDD/total lipids†
PCDF/total lipids†(pg/g) (pg-TEQ/g) (pg/g-fat) (pg-TEQ/g-fat) (pg/g-fat) (pg-TEQ/g-fat)

9.40
3.40
2.50
2.50
11.0
3.00
6.10
5.50

0.30
0.10
0.00
0.20
1.10
0.22
0.38
0.24

0.68
0.17
0.12
0.18
0.73
0.28
0.43
0.27

0.15
0.05
0.00
0.10
0.31
0.11
0.13
0.12

380
150
200
83
330
86
140
230

26.7
7.60
10.1
6.60
22.7
7.60
9.30
10.9

0
4
0
7
32
6
9
10

6.0
2.0
0.0
3.5
9.6
3.0
3.3
5.0

PCDD, polychlorinated dibenzo-p-dioxin; PCDF, polychlorinated dibenzofuran; TEQ, toxic equivalent.
* Total breast milk.
† Total lipids of breast milk.

GC and GC/MS conditions for fatty acidanalysis

Separation before GC and GC/MS analyses

The analysis of fatty acids was performed at the
Tottori University Faculty of Medicine Mass
Spectrometry Laboratory. Breast milk was
methylesterized according to the method of
Yamamoto (1962). Quantitative analysis was
performed by a Hitachi G-5000 gas chromatograph. A JMS-DX 303 (JEOL, Tokyo, Japan)
and a GC 5890 (Hewlett Packard, Avondale,
PA) were used for qualitative analysis by GS/MS.
GC conditions for the analyses were as follows: Carrier gas was helium (35 mL/min).
The initial temperature was held at 150˚C for 2
min, and then raised at a ratio of 5˚C/min to
270˚C and finally retained at 270˚C for 15 min.
The temperature of the injector port was 250˚C,and detector, 300˚C. A capillary column DB–5
(J & W Scientific Co., Folsom, CA) (weak polarity; internal diameter 0.25 mm; film 0.25 µm;
length 30 m) for GC fatty acid analysis was
employed.
Mass spectra were measured by positiveelectron impact ionization at 70 eV and 300 µA.
The capillary column from the CBP 1 (J & W
Scientific Co.) (internal diameter 0.25 mm;
length 25 m) was employed for GC/MS use.
The fatty acid concentration was standardized
by heptadecanoic acid (C17:0) as the standard by
an area ratio.

The extraction of dioxin types was performed
based on guidelines set by the Environment Agency of Japan Dioxin Risk Evaluation Committee(1998a). The typical process has usually followed
the guideline of the Environment Agency ofJapan. Separation, extraction and methylesterification of fatty acids were based on the modification of the method of Yamamoto (1962) and
Maeda et al. (1996).

Results

Dioxin content in breast milk
Tables 2 and 3 show the PCDD and PCDF contents in breast milk samples obtained from the 8primiparas. The concentration of dioxin is reported by a quantity, that is, toxic equivalent(TEQ) of total dioxins (PCDDs + PCDFs). The
TEQ is the sum of every chemical isomers. The
toxicity of dioxin differs for every chemical isomer. Because the toxicity of 2,3,7,8-4 chloridation is the strongest among isomers, that of theother isomers is expressed by toxic equivalency
factor (TEF), as relative toxicity for 2,3,7,8-4
chloridation (TEF = 1) (Miyata, 1998a). We
calculated total dioxins as the sum of PCDDs
and PCDFs in pg-TEQ, to exclude coplanarpolychlorinated biphenyl.

105

M. Sampei et al.

Table 3. Concentration and TEQ of total dioxins (PCDDs + PCDFs)
Samplenumber

PCDDs + PCDFs/total breast milk
(pg/g)(pg-TEQ/g)

1
2
3
4
5
6
7
8

9.7
3.5
2.5
2.7
12.1
3.2
6.5
5.7

PCDDs + PCDFs/total lipids of breast milk
(pg/g-fat)(pg-TEQ/g-fat)

0.83
0.22
0.12
0.28
1.04
0.39
0.56
0.39

380
154
200
90
362
92
149
240

32.7
9.6
10.1
10.1
32.3
10.6
12.6
15.9

PCDD, polychlorinated dibenzo-p-dioxin; PCDF, polychlorinated dibenzofuran; TEQ, toxic equivalent.

5International ranges of the contents excluding Japan
Domestic ranges of the contents

Frequency

4

3

2

1

0
0-4

5-9

10-14

15-19

20-24

25-29

30-34

35-39

40-44

45-49 (pg-TEQ/g-fat)

Total dioxins in total lipids of breast milk
Fig. 1. Histogram of toxic equivalents (TEQ) for total dioxins (PCDDs + PCDFs)
in the total lipids of breast milk.

Table 2 shows the PCDD content in total breast
milk ranging from 0.12 to 0.73 pg-TEQ/g and
the PCDF content ranging from 0 to 0.31 pg-TEQ/
g. The total dioxin (PCDDs + PCDFs) content in
total breast milk ranged from 0.12 to 1.04 pgTEQ/g (average 0.48 pg-TEQ/g) (Table 3).
On the other hand, the PCDD content in the
total lipid amount of breast milk ranged from
6.6 to 26.7 pg-TEQ/g-fat and the PCDF content,
from 0 to 9.6 pg-TEQ/g-fat (Table 2). The total
dioxin (PCDDs + PCDFs) content in the total
lipid of breast milk ranged from 9.6 to 32.7 pg-

TEQ/g-fat (average 16.7 pg-TEQ/g-fat). Figure 1
shows a histogram of the total dioxin content in
the total lipids of breast milk. Primiparas 1 and5 had abnormally high levels at 32.3 and 32.7
pg-TEQ/g-fat, but the other 6 primiparas had
lower levels, 9.6 to 15.9 pg-TEQ/g-fat.
Their PCDD/PCDF ratio was about 2 times
higher than that (42/30 = 1.4) analyzed fromfood intake in an adult population in the UnitedStates (Schecter et al., 2001).

106

Dioxins and fatty acids in breast milk

(pg-TEQ/g)
1.2

Relationship between the dioxin and lipid contents

No. 5

Total dioxins
in total breast milk

1.0

Figure 2 shows the relationship of the dioxin
content in TEQ to the lipid content in breast
milk. The lipid content was 1.25% to 4.31% inbreast milk (Table 1). Exclusive of primiparas
1 and 5, the dioxin content in TEQ showed ahigh correlation (r2 = 0.819) to the lipid content.
Correlations were also high between TEQbased contents of PCDDs and PCDFs in total
breast milk and in total lipids of breast milk
(Fig. 3).

No. 1
0.8

No. 7

0.6

No. 8

0.4

No. 2
0.2

y = 0.132x - 0.044
r 2 = 0.819

No. 3
0.0

No. 6
No. 4

0

2

4

6 (%)

Total lipids of breast milk

Fatty acid composition of breast milk
Fig. 2. Relationship between the total lipid anddioxin contents in breast milk. TEQ, toxic equivalent.

The representative GC tracings of isolated fatty
acids and internal standard fatty acid are shownin Fig. 4 (methylesters). Identification of eachfatty acid methylester was from a fragment pattern in the mass spectrum (Fig. 5). The mostconcentrated fatty acids in breast milk of the 8primiparas were C16:0 and C18:1. The commonest fatty acids were C12:0, C14:0, C16:1, C18:2 andC18:0. The fatty acids in trace amounts were

(pg-TEQ/g-fat)
12

PCDFs
in total lipids of breast milk

(pg-TEQ/g)
0.4

y = 0.330x + 0.003
r 2 = 0.738

PCDFs
in total breast milk

C10:0, C20:1, C20:2, C20:3, C20:4, C22:5 and C22:6.
GC showed a similar tendency in the distribution patterns of these fatty acids throughout the
8 primiparas.

0.3

0.2

0.1

0.0
0.0

8

4

y = 0.279x + 0.515
r 2 = 0.544

0
0.2

0.4

0.6

0.8

PCDDs
in total breast milk

1.0

1.2

0

(pg-TEQ/g)

10

20

30

40
(pg-TEQ/g-fat)

PCDDs
in total lipids of breast milk

Fig. 3. Relationship between the PCDD and PCDF contents in total breast milk of 8 primiparas (left)
and in total lipids of breast milk (right). PCDD, polychlorinated dibenzo-p-dioxin; PCDF,
polychlorinated dibenzofuran; TEQ, toxic equivalent.

107

M. Sampei et al.

C16:0

22.5

15.9

C18:1

11.1

C14:0

C12:0
C20:4

C20:2
C22:6

50

35.0

45

35

30

25

20

15

10

5

C22:5

40

34.8

23.3

C20:1
29.7

28.8

19.2

C18:0

4.6

15.1

C10:0

22.0

C18:2
C16:1

C20:3

28.1

C17:0

29.5

7.4

Standard(min)

Retention time
Fig. 4. Gas chromatogram of methylester of fatty acids from primipara 3.

Fig. 5. Mass spectrum of methylester of C18:2 from primipara 3.

Discussion

Factors controlling the dioxin content inbreast milk
We measured the level of dioxins in breast milkof 8 primiparas in Yonago district. Only thebreast milk of primiparas was used as samples,
because PCDDs and PCDFs in the breast milkof primiparas are at significantly higher levelsof concentration than in multiparas (Vartiainen,
1997; Iida et al., 1999). The total dioxin content
we measured in total lipids of breast milk ranged from 9.6 to 32.7 pg-TEQ/g-fat (average 16.7
pg-TEQ/g-fat). The ranges of dioxin content
reported in Europe and Asia were from 6 to 40
pg-TEQ/g-fat (average 21 pg-TEQ/g-fat) (Environment Agency of Japan Dioxin Risk Evaluation committee, 1998b). Domestic research

108Dioxins and fatty acids in breast milk

Table 4. Fatty acid compositions in breast milk 1 week after childbirthPeaknumberRetention
time
(min)

2
(mg/g)

3(mg/g)

Sample number
4
5
6(mg/g) (mg/g) (mg/g)

7(mg/g)

8(mg/g)A (C10:0)
1 (C12:0)
2 (C14:0)
3 (C16:1)
4 (C16:0)
6 (unknown)
7 (C17:0)*
8 (C18:2)
9 (C18:1)
10 (C18:0)
11 (C20:4)
12 (C20:3)
13 (C20:2)
14 (C20:1)
15 (unknown)
16 (C22:6)
17 (C22:5)

4.6
7.4
11.1
15.1
15.9
18.4
19.2
22.0
22.5
23.3
28.1
28.8
29.5
29.7
34.6
34.8
35.0

0.38
2.71
4.75
1.64
11.65
0.38
3.00
3.98
12.58
3.02
0.25
0.22
0.28
0.40
0.24
0.11
0.14

0.16
1.29
2.47
0.92
7.60
0.08
3.00
4.15
10.85
1.58
0.24
0.17
0.26
0.28
0.17
0.63
0.34

0.55
3.71
6.17
2.93
18.35
0.21
3.00
6.52
14.30
3.25
0.49
0.47
0.44
0.53
0.20
1.12
0.40

0.63
2.96
3.45
1.41
11.66
0.13
3.00
4.14
13.86
3.73
0.34
0.22
0.27
0.36
0.13
0.78
0.23

1.10
5.29
6.70
2.95
17.48
0.25
3.00
9.03
19.75
3.45
0.48
0.36
0.56
0.61
0.15
0.88
0.31

0.67
3.28
4.41
2.91
19.47
0.28
3.00
11.66
21.97
4.03
0.59
0.45
0.61
0.75
0.10
0.72
0.33

0.25
1.76
3.27
1.82
12.25
0.14
3.00
3.87
17.83
3.14
0.37
0.24
0.56
0.61
0.13
0.80
0.42

45.74

34.18

62.63

47.30

72.34

74.56

50.47

Total
* Standard.

has reported levels of 10.9 to 44.6 pg-TEQ/g-fat(average 23.9 pg-TEQ/g-fat) in total lipids ofbreast milk (Akita 10.9; Sendai 11.4; Niigata
18.3; Saitama 22.8; Hamamatsu 28.1; Osaka 44.6;
Nara 40.5; Fukuoka 15.0; Okinawa 23.6 pgTEQ/g-fat) (Miyata, 1998b; Saitama Prefecture
Health and Welfare Division, 1998). The mean
dioxin level we found in Yonago district was
somewhat lower than these levels.
The total dioxin concentrations of the 8 primiparas were abnormally higher in 2 mothers(32.3 and 32.7 pg-TEQ/g-fat) than in the 6others (9.6–15.9 pg-TEQ/g-fat). This does notseem to be due to their body size (height andweight in Table 1) or breast milk secretingstates, but to differences in dietary habits.
Table 1 shows daily food data obtained from the
8 primiparas during personal interviews. For
primipara 1 with a high dioxin content in breast
milk, her vegetable intake was extremely low,while the other primiparas ate a good amount ofvegetables every day. This primipara normallyate fish and meat frequently, about 2 to 7 times
a week.

According to the Fukuoka Prefecture Health
Environment Research Laboratory (Miyata,
1998a), food fiber including cellulose absorbs
dioxins in the small intestine, which are durable
in the excretion of feces. Consequently, the reason why the dioxin content was high in primipara 1 might have been because of her low vegetable intake, although the number of breast milk
samples analyzed may not have been necessarily adequate.
The 2nd-highest content of dioxins was inprimipara 5 which requires another explanation. Although she had a high intake of vegetables, she had lived near a garbage incinerator
in Osaka for a long time. Considering that approximately 80% of dioxins comes from trashburning facilities (Miyata, 1998a), the primaryfactor of her high content may be because of her
residential environment. To uncover this as apossible cause, it should be further examined
whether the primipara was a first born child or
not, or how old she was when she delivered her
first child.

109

M. Sampei et al.

(pg-TEQ/g-fat)

Total dioxins
in total lipids of breast milk

35

No. 1

No. 5

30
25
20

No. 8
15

No. 7
10

No. 3

No. 2 No. 4 No. 6

5
0

0

2

4

6 (%)

Total lipids of breast milk
Fig. 6. Relationship between the lipid content inbreast milk and the total dioxin content in total lipids
of breast milk. TEQ, toxic equivalent.

The effects of smoking on the concentrationof dioxins are not discussed in the present paper.

Relationship between the dioxin and lipid/
fatty acid contents
The GC patterns of distribution of common
fatty acids were similar through out the 8 primiparas, as shown in Fig. 4. These results indicate that there was no clear relationship between the dioxin content and fatty acid composition. The most concentrated fatty acids were
C 16:0 and C 18:1, in accordance with previous
reports (Yamamoto, 1962; Maeda et al., 1996).
The concentration of all fatty acids in breast
milk ranged from 34.2 to 74.6 mg/g (average
55.3 mg/g) 1 week after childbirth (Table 4),
and from 41.8 to 89.2 mg/g (average 69.7 mg/g)
1 month after childbirth (data not shown). The
total lipid content in breast milk 1 month after
was 2.4 times (average 1.43 times) higher thanthat 1 week after (Table 4). Fatty acid C18:2
commonly increased 1 month after. C18:2 is an
important fatty acid for controlling the concentration of cholesterol in the plasma of the newborn (Potter and Nestel, 1976).

Our results suggest that the dioxin content inbreast milk is not related to a specific fatty acid.
However, a probable correlation was indicatedbetween the dioxin and total lipid contents inbreast milk, as shown in Fig. 2. PCDDs and
PCDFs are dispersed equally among the lipid
compartments of breast milk (Przyrembel et al.,2000). A higher lipid content (2–7%), on thecontrary, is negatively correlated with the dioxin content in total lipids of breast milk (Saitama
Prefecture Health Welfare Division, 1998).
This could be due to a diluting effect of dioxinsby lipids. However, our results did not showsuch a diluting effect, and we proved constant
TEQ-based levels except for the 2 abnormallydioxin-abundant breast milk specimens of primiparas 1 and 5 (Fig. 6). In these cases, wemust take notice that the total amount of dioxins
in breast milk increased as the lipid content increased.

Aknowledgments: We are grateful to Professor Naoki
Terakawa, Division of Reproductive-Perinatal Medicine and Gynecologic Oncology, School of Medicine,
Professor Takako Maeda, Department of Women’s andChildren’s Family Nursing, School of Health Science,
Tottori University Faculty of Medicine, and Chief
Nurse Nobuko Inada, Division of Maternity Services,
Tottori University Hospital, for thier kindness in encouraging us throughout this study. We also thank the 8primiparas hospitalized at Tottori University Hospital. Our special appreciation goes to Mr. Takashi
Nakamura of the Hiroshima Environment and Health
Association, for his pricise analyses of the dioxin specimens.
This study was supported by a research grant of
Tottori University College of Medical Care Technology, 1998.

110

References
1 Environment Agency of Japan Dioxin Risk Evaluation Committee. [Risk evaluation of dioxine.]Tokyo: Chuo Hoki Shuppan; 1998a. p. 128 (inJapanese) [GC/MS operating conditions recommended].
2 Environment Agency of Japan Dioxin Risk Evaluation Committee. [Risk evaluation of dioxine.]Tokyo: Chuo Hoki Shuppan; 1998b. p. 112 (inJapanese) (Table 5-2: [mean dioxin content ofbreast milk in several countries]).

Dioxins and fatty acids in breast milk

3 Iida T, Hirakawa H, Matsueda T, Takenaka S,
Nagayama J. Polychlorinated dibenzo-p-dioxins
and related compounds in breast milk of Japaneseprimiparas and multiparas. Chemosphere 1999;
38:2461–2466.
4 Kayama F. [The problems of endocrine disruptors.]
Kagaku 1998;53:12–15 (in Japanese).
5 Kiviranta H, Purkunen R, Vartiainen T. Levels
and trends of PCDD/Fs and PCBs in human milkin Finland. Chemosphere 1999;38:311–323.
6 LaKind JS, Berlin CM, Naiman DQ. Infant exposure to chemicals in breast milk in the UnitedStates: what we need to learn from a breast milk
monitoring program. Environ Health Perspect
2001;109:75–88.
7 Maeda T, Takayama M, Sampei M, Kasagi T,
Tanaka T, Iwai N, et al. Study on fatty acid composition in pregnant serum and puerperal breast
milk: especially of eicosapentaenoic acid. Tottori
Daigaku Iryo Gijyutsu Tanki Daigakubu Kiyo
1996;25:15–24 (in Japanese with English abstract).
8 Matsuo M. [Investigation on resemblance ofsynthetic chemical substance and hormone.]
Kagaku 1998;53:23–26 (in Japanese).
9 Ministry of Health and Welfare of Japan. [Standard manual for analysis of dioxin and related
compounds contained in waste disposal, 1997.]
Tokyo: Ministry of Health and Welfare of Japan;
1997. Notification No. 234:1122–1126 (in Japanese).
10 Ministry of Health, Labour and Welfare of Japan.
[Summary of the fiscal 1997–1999 Ministry of
Health, Labour and Welfare study reports on theconcentration of dioxin and related compounds inbreast milk.] Ministry of Health, Labour and Welfare of Japan [online] 2000 Dec 28 [cited 2001 Jul
3]: [10 screens]. Available from: URL: http://www.
mhlw.go.jp/topics/0012/tp1228-1.html.
11 Miyata H. [To understand dioxin contamination.]
Tokyo: Godo Shuppan; 1998a. pp. 29–30 (in Japanese) (Table 3).
12 Miyata H. [Mean dioxin content of breast milk inseveral cities in Japan.] In: Katei Eiyo Kenkyukai[home nourishment research society], ed. [Stop!

Dioxin contamination of food and breast milk.]
Tokyo: Hon No Izumisha; 1998b. p. 311 (Table 13)(in Japanese).
13 Potter JM, Nestel PJ. The effects of dietary fatty
acids and cholesterol on the milk lipids of lactating women and the plasma cholesterol of breastfed infants. Am J Clin Nutr 1976;29:54–60.
14 Przyrembel H, Heinrich-Hirsch B, Vieth B. Exposition to and health effects of residues in human milk. Adv Exp Med Biol 2000;478:307-25.
15 Saitama Prefecture Health and Welfare Division.
[Report on dioxin and related compounds inbreast milk findings of the fiscal 1997 survey.]
Saitama: Saitama-ken Kenko Fukushi-bu; 1998
(in Japanese).
16 Sakai S. [Trash and chemical substance.] Tokyo:
Iwanami Shoten; 1998 (in Japanese) (Iwanami
Shinsho No. 562).
17 Schecter A, Cramer P, Boggess K, Stanley J,
Papke O, Olson J, et al. Intake of dioxins and related compounds from food in the U.S. population. J Toxicol Environ Health 2001;63:1–18.
18 Schuler F, Schmid P, Schlatter C. Transfer ofairborne polychlorinated dibenzo-p-dioxins anddibenzofurans into dairy milk. J Agric Food
Chem 1997;45:4162–4167.
19 Vartiainen T, Saarikoski S, Jaakkola JJ,
Tuomisto J. PCDD, PCDF, and PCB concentrations in human milk from two areas in Finland.
Chemosphere 1997;34:2571–2583.
20 Watanabe S, Kitamura K, Nagahashi M. Effects ofdioxins on human health: a review. J Epidemiol
1999;9:1–13.
21 Yamamoto Y. The fatty acid compositions ofhuman colostrum and of mature milk fats frommothers on diets taken ad libitum and theirchanges during the course of lactation. Shonika
Kiyo 1962;8:284–291 (in Japanese).

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Received October 10, 2002; accepted October 29, 2002

Corresponding author: M. Sampei