HEALTH AND NUTRITION NEWS
No.5
September 15, 2003

National Institute of Health and Nutrition

CONTENTSPREFATORY NOTE
Mecca of the Research for Health and Nutrition ・・・・・Masahiro Takaishi
CURRENT RESEARCH PROJECTS
Challenge of Office of International Collaboration ・・・・・Hidemi Takimoto
THOUGHTS ON HEALTH AND NUTRITION RESEARCHThe Satiate Age・・・・・・・・・・・・・・・・・・・・・Fumiko Hirahara
RESEARCH FINDINGS
Low fish oil consumption inhibits SREBP-1 proteolytic activation, and highlevel consumption suppresses SREBP-1 expression・・・・Teruyo Nakatani
Diurnal variations in human urinary excretion of nicotinamide catabolites
Effect of stress on the metabolism of nicotinamide・・・・Mamoru Nishimuta
Bowel habits among the Japanese population・・・・・・・・Kumae Takashi-1-Mecca of health promotion research
Expectation for National Institute of Health and Nutrition
TAKAISHI, Masahiro
Ex director general of National Institute of Public Health
Rapid progress is expected in the area

Japanese.

of "health promotion" by the act of the “HealthPromotion Law”.

I hear that

It is well known that this law

thesetwomissions

has its background in the "Health Japan 21”

areproject.

It cannot be overemphasized that

improving with three"Health Japan 21” specifies the direction of thedepartments such as

national health promotion movement in the 21stDepartment

century as the third measure of national health

Humanpromotion.

Department

While decentralization advances

steadilyof

Nutrition,ofthese days, local municipalities strive to makeNational Health and Nutrition Survey-Healthhealth promotion programs, one after another.

Informatics, and Department of Food Science

Either on a national or on a local
government

level,

newpolicies

And there are alreadybegreat interests for the results of these researches.

The direction ofEspecially, I am interested in the achievement of

the policy becomes clear when scientific evidence

the human metabolic project by the firstisareconstructed human calorimeter in Japan. Theundertaken. All research institutes must makeresults of this project would be reflected in theefforts for research with outstanding ideas anddecision of the 7th revision of the Dietary

steady application.

Reference Intakes of the Japanese and also

supported by scientific proofs.

accumulatedandexactmust

Research for Health.

analysesThus, expectation to the National

become a firm foundation of national healthInstitute of Health and Nutrition is quite large.

promotion based on the scientific evidence.

It is the only research institute which conducts

There is no doubt that all other studies are

scientific studies to support national healthprogressing in the same way.

promotion policies.

It is definitely the “Mecca

I sincerely hope for the long future ofof health promotion research.”

continuing success of National Institute ofIn the directory of Incorporated

Health and Nutrition, as a “Mecca of healthAdministrative Agency National Institute ofpromotion research”.

Health and Nutrition, the mission of thisinstitute is clearly written as;
1)

Researches for health promotion to improveoverall health of the nation.

2)

Researchesfornutrition

anddietin-2-Current Research Project Introduction
Challenge of Office of International Collaboration
Center for Collaborative Research
Senior Researcher, Hidemi TakimotoCollaboration takes charge of answering theserequests and questions and organizes thematters according to the needs. Even though
this office has just established and as new as
OfficeforPromotionofIndustry-University-Institute Cooperation, it
has the great responsibility to act as a contact
point to flourish the exchange between NIHNand foreign researchers and develop cooperative
researches.
On January 16, 2004, Office ofInternational Collaboration will host its first
Asian Network Symposium entitled “Optimizing
maternal and child nutrition for the preventionof chronic diseases”.
These days, in mostcountries in South-East Asia, statistics show thequite high ratio such as 20~50% of children areborn as low-birth- weight (less than 2.5kg atbirth). These children tend to suffer fromchronic diseases such as ischemic heart disease,diabetes, and/or high blood pressure as adults.
Urgent prevention starting from a baby in themother’s womb or in infant age is needed. Topromote health of the children who shoulder thefuture, we need the action foresees the risk offuture diseases. I would like to exchange theknowledge with Asian researchers from thispoint of view at the symposium. The detailed
program will be soon available on our website, soplease keep it in mind and join us at the Asian
Network Symposium!

Japan is known as one of the most
longevity countries in the world. Not only
foreign researchers of health and nutrition, butalso people who are in charge of nutrition policy
or nutritional ventures are very much interestedin why so many Japanese are able to keep theirhealth and longevity. Their interest are mainly
caused by Japan’s uniqueness of being the only
country in developed countries without
demonstrating the upward trend of death rate ofischemic heart disease which is one of the
popular diseases of arteriosclerosis.
Although we can be proud of our long
history of the national monitoring system of
health and nutrition, “National NutritionSurvey”, and its huge pile of the reports, it is notrealistic for the foreigners to read and consult“The Current Status of National Nutrition”, oneof the reports. It is clear that the past effort toshare these information and our experienceswith other nations had not been enough. Up
until quite recently, even in NIHN, researchers
had had to answer the request individually suchas provision of information from internationalorganizations such as WHO or FAO, questions
about Japanese nutritional research fromforeign researchers and companies.
Also,provision of professional knowledge and skills todecision and operation of nutritional measure in
Asian countries were mostly handled by somevoluntary researchers.
Now,OfficeofInternational-3-Thoughts on Health and Nutrition Researches
The Satiate Age ~ How long we can call it “ Japanese Tea” ?
Fumiko Hirahara
Division of Food Science
MealSolution,
Home
Meal
Replacement, Eat-in, Convenience Food,
Dlicatessen, Copied Food, citrulline, etc. Thesehazards.”
Nowadays we hear of “queer eating(strange combination of foods)”, such as mixing
up all the food and sauce with boiled rice to eat,typically observed in young people. This was
also introduced in a TV program, and somepeople said it was disgusting. But a dietician
said, “It doesn’t matter so far as they eat abalanced diet.”
There are three functions in foods; 1)
Filling up, 2) Enjoying taste, shape, color,fragrance, and texture, 3) Maintaining one’s
health (The function of food).
Recently,
although the 3rd function comes under the
spotlight as well as the 2nd attracts the gourmet,
number of people grows who just take food tofulfill his/her stomach and pay no attention to
2nd or 3rd values.
We import a variety of foods fromother countries to fill our stomach, such as riceand Japanese tea. Both of them are estimated tokeep a high self-sufficiency rate, but I wonder
how long we can call it as “Japanese tea” or“Japonica rice”. I find “Japanese tea” without
real Japanese tea taste, or “wash-free rice” withless taste and texture. Is it possible to keep ourhealth with these foods?
We are living in an age that one has totake responsibility to keep and improve his/herhealth. I think it is very important to us, thespecialists, how and what kind of health related
information to offer to public nearly drowning in
the flood of information

are the key words in the questions from people
in recent ten days. As these show, we are living
in a raging flood of information on healthincluding many foreign terms.
Reflecting
people’s health concerns, there is at least one
program focusing on food and diet, whenever
you turn on the TV. Some programs pick up
real hot news from professional journals, even I
my self learn from TV sometimes. But usually,
I watch this kind of shows wondering how muchof these issues can reach to the audience and beunderstood.
Not only about these BIG words above,of course there are well thought inquiries aboutsuch issues; “consumption at a place ofproduction”, “prepared meals”,
each mealperfect”, “ solitary eating”, and “education
through intakes”. Some asked me about Dr.
Hayami’s and Dr. Saiki’s researches, or evenwanted to know about achievement over a half
century ago in “Food Analysis Conspectus：Firstedition of Food analysis (document reports)”. It
is interesting that some seem to want semblanceof health information, on the other hand, somepursue substantial knowledge.
There are some pathways ofinformation flow.
S to S (Specialist toSpecialist) and S to M (Specialist to Mass mediaand to public) are well known. We have to becareful because when information flows in an
inappropriate way, it can possibly cause “health-4-Current Research Findings
Low fish oil consumption inhibits SREBP-1 proteolytic activation, and high level
consumption suppresses SREBP-1 expression
Division of Clinical Nutrition
Teruyo Nakatani
Fish is well known as a healthy food.

It has been assumed that the decrease

Fish consumption prevents chronic diseases

in SREBP-1c due to polyunsaturated fatty acidsuch as ischemic heart disease and stroke.

was regulated at the messenger RNA level, butWhat is the reason for these health effects?

Fat

our study revealed that the intake of fish oil at

is considered unhealthy, but some fat is needed

usual dietary levels controlled SREBP-1c levels

for your body.

Therefore, the body tries toin liver through “suppressing the activation ofmaintain its fat volume at a certain range.

SREBP-1c protein”, which means that theWhen there is loss of body fat, the body tries toamount of SREBP-1c acting as a transcription

increase it.

factor decreased; therefore suppressing lipid

We need to produce enzymes forlipid synthesis, and we need “transcriptionsynthesis.

factors” for these enzyme production.

by the diet, through the expression of certainAll

The metabolic processes are affected

metabolic processes going on in our organs are

genes

chemical reactions, and these reactions needtranscription factors.

enzymes.

suchaschanging

theamountof

When a transcription factor works

Changing our usual diet may keep us

for lipid synthesis, the enzyme needed isaway from life-style related diseases, such asproduced, and then lipid synthesis starts.

fatty liver and atherosclerotic disease.

Consumption of fish oil is known todecrease the transcription factor SREBP-1c

Source: A low fish oil inhabits SREBP-1 proteolytic

needed for lipid synthesis. In our study, we fed

SREBP-1 mRNA in mice liver: relationship tocascade, while a high-fish-oil feeding decreases
anti-obesity.

10~60 fat energy percent of fish oil to mice, andNakatani T, Kim H-J, Kaburagi Y,

Yasuda K, Ezaki O : J. Lipid. Res.:44(2):369-379, 2003

examined the change in SREBP-1c.

-5-Current Research Findings
Diurnal variations in human urinary excretion of nicotinamide catabolites
Effect of stress on the metabolism of nicotinamide
Division of Human Nutrition
Mamoru Nishimuta5) Urine samples were collected and pooledduring 5 specific periods (0630 to 0830, 0830 to1300, 1300 to 1830, 1830 to 2200, 2200 to 0630 of
the next day).
We determined the amount of
catabolites of niacin excretions in urine such as
N1-methylnicotinamide(MNA),
N1-methyl-2-pyridon-5-carboxyamide (2-py), andN1-methyl-4-pyridon-3-carboxyamide (4-py), andobserved the diurnal rhythm and the effect ofstress on niacin metabolism. For a comparison,
we took the value of the excretionfrom the day with same menu without stresstests.
As a result, it became clear that there
was a daily rhythm in the metabolism of niacinwith urine analysis. Taking into account of the
enzymatic process of synthesis and degradationof niacin, the intake of total niacin per day wasenough in this experiment. Also it can be said
that niacin is used mainly in the day time whileenergy expenditure level is high, and during thenight time the usage of niacin decrease and fully
preserved. This is why MNA level was higher
in the early morning urine.
From the stress exposure experiment,
MNA and niacin catabolites in total increased
only with cold stress. This means that cold
stress activated the energy expenditure alongwith niacin synthesis from tryptophan.

Human studies are indispensable for
examining human nutritional requirements.
“Niacin”, one of the water-soluble vitamins, isthe generic name for nicotiamide and nicotinicacid, both are stored in liver. One of the featuresof this vitamin is that it is synthesized fromtryptophan (one of the essential amino acids) inthe body, and plays an important role in theenergy metabolism.
In order to examine the dietary niacin
requirement, we conducted the 12 days
experiment at the NIHN with 12 female
university students’ volunteers. The protocol
was as follows:
1) Four daily menus were devised and were fedin rotation.
2) Daily energy intake was 1890kcal/ day.
3) Meals included 13.3mg niacin and 706mg
tryptophan (which will be converted into
11.8mg niacin). Niacin equivalent was25.0mg/ day.
4) First 4 days were for adaptation, then, thesubjects experienced one of the following
artificial stresses once in the followingperiod.
(1) Cold exposure: staying in a 4℃ room,
two and half hour in the morning and in
the afternoon.
(2) Calculation: three hours non-stop
calculation with 3rd graders level in themorning and in the afternoon.
(3) Dark exposure: sitting and keeping
silence on a chair without backrest threehours with wearing eye mask in a darkroom in the morning and in theafternoon.

Source: Diurnal variations in human urinary excretionof nicotinamide catabolites; effects of stress on themetabolism of nicotinamide. Okamoto H, Ishikawa A,
Yoshitake Y, Kodama N, NIshimuta M, Fukuwatari T,Shibata K. Am J Clin Nutr:77:406-410, 2003

-6-Current Research Findings
Bowel habits among the Japanese population
Division of Health Promotion and Exercise
Takashi Kumae
Colon diseases, including cancer anddiverticulitis, have been increasing recently inJapan. This is probably related to bowel
disorders such as constipation, however, details
regarding bowel habits among the Japanese
population are very rarely published ordiscussed in the public domain. To clarify thisissue, it is important to examine the relationshipbetween colon diseases and bowel disorders. On
the other hand, the defecatory status of subjects,
especially constipation, are decided subjectively
in daily life, though several definitions fordefecatory condition are used in the scientificfield. However, studies detailing self-evaluationof the defecation status in general population
study groups do not exist; this may be attributed
to difficulty in obtaining objective assessmentsof bowel habits.
We conducted a research study basedon a structured interview involving 1,195
residents (40 years old and beyond) from rural
areas in Iwate-ken (a prefecture in north-eastJapan) about their bowel habits. The interview
elicited responses to a number among
self-reported bowel habits, including “Bowelmovement frequency”; “Length of time for bowelmovement”; “Straining after bowel movement”;“Regular bowel movements” “Changes in bowel
movements associated with journeys away fromhome”;“Alternatingdiarrhea/constipation
disorder”; “abdominal pain associated withbowel movement; and “Stool appearance”.
The status of defecation wascategorized under 1) normal, 2)marked
constipation 3)moderate constipation, 4)mild
constipation,
5)
alternating
diarrhea/constipation
disorder,6)diarrhea.
When the results were analyzed according to sex,more males answered “normal” (79.3%)
compared with females (60.5%). The results
also clearly showed that the proportion of
constipation was greater in females than inmales, with respective men and women
responses for marked, moderate, and mild
constipation of 3.6%/6.3%, 3.9%/14.2%, and6.3%/15.5%, respectively. On the other hand, theincidence of diarrhea was greater in males thanin females at 3.9% compared with 1.8%. Whenthe data were analyzed by age, more women in
any age group tend to be constipated than men,and the constipation tendency increased in bothgenders concomitantly with age. The reasons-7-

for this can be assumed to be; 1) Decreased large
bowel function with increasing age, and 2)
Decreased fiber intake associated with lower
energy intake.
Additionally, a logistic regression
analysis was carried out to analyze theassociation
betweenthecomplaintofconstipation and the other eight parameters,
and the odds ratio for each parameter wascalculated. The highest odds ratio value wasseen for the item “Bowel movement frequency”;
especially the value “Once per three days ormore” was noted in both genders (odds ratio:
13.38 and 42.46 in men and women,respectively). In addition, “Stool appearance”,“Length of time for bowel movement”, “Strainingafterbowelmovement”,“Alternatingdiarrhea/constipation/ disorder” and “Changes
in bowel movements associated with journeys
away from home” were significantly related withthe complaint of constipation in both genders.
All such parameters were thus utilized by thesubjects themselves to evaluate constipation in
the general population. On the other hand, theodds ratio for “Abdominal pain associated withbowel movement” was not significant for women,in contrast to that for men. In conclusion, theitem “Bowel movement frequency” was limited
as an objective index for evaluating bowel habits,
if only this parameter is assessed.
Our data allowed us to clarify thedifferences in the status of defecation by genderand age group. It would be of great help when
discussing of epidemiological research to elicit
and elucidate the relationships between large
bowel diseases and defecation. Our data also
revealed the status of personal judgment
regarding constipation, which should help toestablish clinical guidance during the treatmentof constipation.
Source: Bowel habits among the Japanese Population.
Matsuzaka M, Nkaji S, Umeda T, Suzuki K, Sugawara
K, Sakamoto J, Wada S, Kumae T, Tokunaga S: J Phys
Fit Nutr Immunol 13:9-16