HEALTH AND NUTRITION NEWSNo. 12June 15, 2005

Table of Contents
Prefatory Note
Interviews with new Director-General……………..………………………………………Shaw Watanabe

CURRENT RESEARCH PROJECTS
Laboratory of Biological Function of Food Component……………………………….……Yoshiko Ishimi

THOUGHTS ON HEALTH AND NUTRITION RESEARCH
Connexin genes have wide range of tumor-suppressive effects.................................... Tomohiro YanoRESEARCH FINDINGS
Effects of tube-fed liquid formula with dietary fiber in the bed ridden elderly patients……………Takashi Kumae
Suppressive Effect of Citrus Aurantium against Body Fat Accumulation and Its Safety……………. Kazuhiro Kubo
Activities of DGAT in the liver, with respect to intra-abdominal obesity and steatosis…………Tomomi Yamazaki© National Institute of Health and Nutrition

Prefatory Note
Interviews with the new Director-General
Shaw WATANABE
Director-General, NIHN
About the supplement use
Since there is no post marketingsurveillance (PMS) for the supplements, I
would like to establish it systematically. For
which, a cohort study by the Nutrition
Representative (NR) and registered dietitians
in cooperation with the food industries could
bring practical and great impacts.
In Japan, there is a traditional terms fromoriental medicine regarding diet for health (e.g.
“shokuyou (=Taking foods in a healthy way forbetter health)”, ”ishoku dogen (=Medicine andone’s daily diet are equally important in making
a sick body well)”), and I would like to establish
the scientific evidence for these terms. So, I
shall work on the management of NIHN incollaboration with various organizations. Since
it concerns “food”, at the governmental level, it
is important to establish the collaboration not
only with the Ministry of Health, Labor andWelfare, but also with the Ministry ofAgriculture, Forestry and Fisheries. The
understanding of Ministry of Education,
Culture, Sports, Science and Technology isalso inevitable for the implementation of“shokuiku (=Promotion of learning on thehealthy diet from an early stage, in particularon the choice of foods, to secure the healthyliving over the course of one’s life). Likewise, aproject for which all the ministries work
together may be needed in the field of healthscience. Since information based on theevidence is highly required, I would enhance
the function as an information center at our
Institute.

As a new Director-General…
Ministry of Health, labor and welfare has
declared to enhance the control oflifestyle-related diseases. This time, I
accepted to take up the present position, andam honored to be the Director-General of theresearch institute with an 85-years history. I
myself have diabetic mellitus, and have been
controlling over the disease well through dietand exercise. Through my experiences, I’m
now well aware that diet and exercise are
essential for the healthy living. Generally,
people in good health are not conscious ofbeing “healthy”, and rather tend to consider“health maintenance” and “health promotion”
as the issue of other people. I hope that our
Institute will accumulate the scientificknowledge necessary for good health,following the “Health Frontier Plan”.
Role of our InstituteSince it is not a big institute, I would aim at
a research institute as think tank open to the
public. The annual National Nutrition Survey
which started after the World War II is a great
asset. “Nutrition” can be largely divided into
two; “preventive nutrition” for health promotion,and “clinical nutrition” in the hospital. So, I
would attempt to organize the team that could
work on both types of nutrition, for which theregistered dietitians may play important roles.
Besides, it is also important to clarify the basic
mechanism by animal experiments and in-vitro
ones, as these finding could eventually beapplied to human beings. In Japan, we used tosuffer from the serious food shortage in thepast, while we are now surrounded by theexcessive foods. In addition, various nutritional
supplements are now widely used seeking for
better health. However, an intervention has
explored that excess intake of β-carotene has
rather negative impacts on human’s health.
Consequently, the importance of human study
is now well recognized.

Foods for specified health use“Therapeutic diets” and “Foods specified
for health use” may sound similar, but there isa significant difference between them. The
former has been utilized for patients in many
hospitals, whereas the latter has insufficientevidence regarding the effects for humanbodies. I think, therefore, the standard should
2Prefatory Noteordinal diets, for which NR could play animportant role.

be revised sooner or later. Since there has
been no systematic evaluation for theapplication to be qualified as the “Foods
specified for health use”, more strict design will
be required in the human studies
Regarding the nutrition labeling, theresponsibility should be basically put on the
consumers themselves as well as the foodcompanies, by which only the products withappropriate label will survive in the market.
However, the labeling of biological andpharmacological functions is practically difficult
with respect to the Pharmaceutical Affairs Law.
Besides, the descriptions of these functions
would contain the technical terms, most ofwhich are difficult for the consumers tounderstand. Yet, the FAO/WHO Codex
Alimentarius Commission now recommends
the labeling of these functions as well, if itreally works on the disease preventions.

Recommendations for the food industry
Human bodies require lipid, protein andcarbohydrate, which are consumed more than
one ton annually. With a rapid increase of
diabetic mellitus and obesity in Japan, it is very
important for us to know the actual energy
intake. Therefore, I would like to request the
food companies to put more easily
understandable nutrition labeling on each foodproducts.
For example, for most of the food products,
energy is shown in the unit of “per 100g”, butwhat we actually would like to know is energy
per packet/serving. In addition, the present
standard for labeling allows that less than fivekcal can be shown as “0 kcal”, but I suggest it
should be more realistic to show it as “< 5 kcal”.
Although food companies tend to fully follow
the ministerial decrees on the standardized
labeling, showing the accurate energy could
earn more trust from the consumers.
Development of low-calorie foods is also very
important in order to control the obesity among
the populations.

About the use of various supplements
Few supplements have the label on the
maximum limit of intake. So, some people may
believe that more intakes should be better. It
must be noted, however, that the excess
intake of even so-called “healthy food” maycause rather negative impacts on health.
The interaction between foods and medicine
has been gradually known. Likewise, thecombined intake of food and supplements
should also be carefully considered.
We, human beings, would take foods
following the experiences of thousands’ years,
while weare not yet certain about theconsequence of the long-termed intake ofsupplements. It is therefore not advisable torely on the supplements only without taking the

From interviews for “Food Industry Newspaper”

ProfilesGraduated from Keio University School of Medicine in 1965. Majored in pathology in the graduate school,
after which he worked for National Cancer Institute (USA) and National Cancer Center (Japan). In 1985, he
was appointed as the chief of Division of Epidemiology, where he explored the new field of cancer etiology
and molecular epidemiology. From 1996, he worked on a new research on “Environment, food, health” at
Tokyo University of Agriculture. He is one of the world authorities in the field of functional food factors. He is
also the Director of Association for promotion of life science. Awarded WHO memorial medal in 1993,
Medical Award of the Japan Medical Association in 1995, and a merit medal from the Japanese
Epidemiological Association. He has been in the present position since 2005.

3

Current Research Projects
Laboratory of Biological Function of Food Components
Yoshiko Ishimi
Division of Applied Food Research
the abnormal bone/lipid metabolism observed
after the menopause. In addition, an experimental
study for animal as well as for human is also
implemented, in order to examine if the
combination of soya diet and exercise could
increase the effects. In the human study, we
instruct the volunteers after menopause tocontinue the quick walking 3 times per week anddaily soybean isoflavone intake, and then, we
keep monitoring the impact on the bone/lipid
metabolism. If the preventive effects of diets andexercise are confirmed from this experiment,
elderly people will be able to enjoy more healthy
life, and thus the medical expenses will be
reduced.
Nowadays, with various health foods
available in the market and overflowing
information, we may find it difficult to decide how
and which foods to choose. Since 2001, theNational Institute of Health and Nutrition has beenworking on the evaluation of the effects ofingredients in the so-called health foods whichhave not been scientifically proved, focusing on
the health effects and safety against the lifestyle
related diseases. Of which, our Laboratory is
responsible for the evaluation on the foodcomponents of health foods that advertise theeffects for maintaining the health of bone andcartilage. Our latest research findings are
updated regularly in the website of our Institute (inJapanese only). Please refer to the following
website for the background information of theabove project; http://www.nih.go.jp/eiken/english/
researchz/ juuten_shokuhin_e.html

Laboratory of Biological Function of Food
Components is mainly in charge of the evaluationof function and health effects of food components
related to bone metabolism and lipid metabolism,
as well as the analyses of “Foods for Special
Dietary Use”.
Although bone may look a calm organ, in
reality, active metabolism takes place. Bonefunctions not only as a supporting organ for thewhole body, but also as storage of calcium (Ca).
Since Ca is the most important mineral tomaintain one’s life, in response to the shortage of
Ca content in the blood, metabolic control works
to stabilize blood Ca level by eluting Ca frombone. Therefore, bone is important organ not only
to support the body, but also for the vital activity.
Determinants of bone mass include genetic
factors, nutrition, exercise, life style and hormone.
In particular, deficient secretion of estrogen after
menopause could bring a serious consequence,that is, a rapid progress of bone loss. Unless one
stores a sufficient bone mass during the youth,bone density will be low due to the menopause
and she will be prone to breaking bones, namely“postmenopausal osteoporosis”. It is estimatedthat about half of Japanese women would
experiencethebonefractureduetopostmenopausal osteoporosis.
Osteoporosis is called as a silent disease, as
it is asymptomatic at the initial stage. Once one
gets bone fracture, however, there is a highpossibility that she will be bedridden for her
remained life. Consequently, QOL of the elderly
will be greatly affected. Recently, Ministry of
Health, Labour and Welfare implements various
policies to reduce the number of elderly persons
who require the long-termed nursing care, of
which we would emphasize that the prevention ofbone fracture should be most important problem.
Under this circumstance, we have beenworking on the researches with the aim toestablish the preventive methods of osteoporosis,
which could be practiced effectively in the daily
life. Focusing on the compounds derived fromSoya that has a weak estrogenic activity, we havebeen investigating the effects of soya intake on
4Thoughts on Health and Nutrition Research
Connexin genes have wide range of tumor-suppressive effects
Tomohiro Yano
Division of Applied Food Researchcells, by controlling the cell attachment andcytoskeletal formation independently of gap
junction, and also as an essential gene forexpression and maintenance of protein necessary
for the normal cell functions.
Furthermore, recent studies showed that
Connexin genes could control comprehensively
the signal system related to invasion andmetastasis, by which invasion and metastasis canbe inhibited even in metastatic malignant tumor
cells. This finding would suggest thattumor-suppressive effects of Connexin genes
could widely contribute to the cancer prevention
and treatment.
In the future, further attempts will be made toestablish the procedures for cancer prevention
and treatment by targeting the recovery of effectsof Connexin genes that work differently by thetype of cancer. I hope that our research team
could make a significant contribution in this study
theme.

Tumor cells are greatly heterogeneous withvarious characters, which is one of the main
factors to make the cancer prevention andtreatment complicated. Antitumor drug does nottake effect all the times, and some of the
carcinoma tissues have the antitumor drug
resistance. Cancer recurrence, invasion andmetastasis are attributable to these resistanttissues, which makes it difficult to recovercompletely. Control of the survival and growth ofthese malignant tumor cells is therefore very
important. Generally, the grade of malignancy isdefined by the level of dedifferentiation from thehighly differentiated normal cells. In order tocontrol the survival and growth of the malignant
tumor cells effectively, it is important to recoverand maintain the functions of gene cluster
necessary for the differentiation of normal cells.
Among these gene clusters, we focused onConnexin genes, which express the gap junction.
Connexin genes maintain the intercellular
homeostasisbyequalizing
intracellularconcentration of hydrophilic molecule (Mw ≤1300)
among adjacent cells, by which the differentiationof cells can be preserved. We, therefore,
attempted to establish the procedures for cancer
prevention and treatment by utilizing thetumor-suppressive effects of Connexin genes.
Fortunately, I was given an opportunity towork at Unit of Multistage Carcinogenesis, theInternational Agency for Research on Cancer(IARC) in Lyon of France for 20 months from
October 1998. IARC is a part of WHO, and was aleading center at that time for the analyses oftumor-suppressive effects of Connexin genes. I
was able to acquire in-depth knowledge on
various tumor-suppressive effects of Connexin
genes, by which I could further develop thesubsequent researches.
Initially, Connexin genes were known mainlyby the expression of gap junction which could
suppress the growth of cancer cell. Later, it was
further explored that Connexin genes widely
contribute to maintain the differentiation of normal
5

Latest Research
Effects of tube-fed liquid formula with dietary fiber in the bed-ridden elderly patients
Takashi Kumae (Division of Health Promotion and Exercise)
A liquid diet fed through a nasogastric tube is used for patients who cannot take a meal orally and ismore physiologic than intravenous feeding. A liquid diet has the added advantage of being adaptable forhome patients because it does not require the same high levels of sterility that are associated withintravenous feeding. A liquid diet is the most nutritionally appropriate for elderly patients bedridden for along term.
Dietary fiber (DF) may be presented in two forms; one is water-insoluble fiber and the other iswater-soluble one. These components have different physiologic and nutritional effects. Digestion in thesmall intestine is affected mainly by water-soluble DF, whereas the regulation of large intestine functions
and fecal excretion are associated mainly with water-insoluble DF. The purpose of a DF-containing liquid
diet include a decrease or elimination of diarrhea, which is the most common complication, and anincrease of stool volume to maintain an appropriate environment in the large intestine.
Oligosaccharides, which are resistant to digestion and absorption in human small intestine, has recently
received attention as a prebiotic or DF.
In this study, a liquid diet containing two kinds of DF (water-insoluble cellulose and water-soluble
oligosaccharide) was administered to twenty-two elderly bedridden patients (9 men and 13 women) for 4
weeks. The effects were monitored by changes in blood parameters and bowel movement. No patients
reported problems associated with blockage of the nasogastric tube due to DF administration.
Although DF is known to inhibit the absorption of nutrients, in this study, body weight of both maleand female increased slightly during the first 15 days of the trial. Besides, there was no change innutritional parameters such as total protein, hemoglobin, albumin, total cholesterol, triacylglycerol, HDL
cholesterol, calcium, iron and magnesium during the administration of liquid diets. These findings would
suggest the beneficial effects of a liquid diet with cellulose and oligosaccharides. It must be noted,
however, that this was a short-termed controlled study, and that a more detailed analysis are required toclarify not only the health effects, but also the possible side effects of DF and oligosaccharides.

A tube-fed liquid formula diet containing dietary fiber increased stool weight in
bed-ridden elderly patients.
Nutrition. 2004 Nov-Dec;20(11-12):955-60.
Nakaji S1), Umeda T1), Kumae T2), Ohta S3), Totsuka M4), Sato K4), Sugawara K1), Fukuda S5).
1) Department of Hygiene, Hirosaki University, Aomori, Japan
2) Division of Health Promotion and Exercise, National Institute of Health and Nutrition, Tokyo, Japan
3) Department of School Health, Faculty of Education, Hirosaki University, Aomori, Japan
4) Department of Health and Physical Education, Faculty of Education, Hirosaki University, Aomori, Japan
5) First Department of Internal Medicine, Hirosaki University, School of Medicine, Hirosaki, Japan

Abstract:
OBJECTIVE: The number of bedridden elderly patients who need a liquid diet has been increasing. We
evaluated the usefulness of a tube-fed liquid diet containing cellulose and oligosaccharide for elderly
bedridden patients. METHODS: Twenty-two elderly bedridden patients were given a liquid dietcontaining cellulose and lafinose for 4 wk. Parameters associated with blood and stool weight were
measured during this period. RESULTS: Stool weight increased by 32.0 g in men and 8.8 g in women at
2 wk and remained at these weights up to 4 wk (P < 0.05 before and after 2 wk, 3 wk, and 4 wk in men,and P < 0.05 before and after 3 wk in women). Body weight increased in men (0.5 kg) and women (0.7kg) 15 d after starting the diet and then remained at these values up to 29 d thereafter, and statisticallysignificant differences were not seen. There were no changes in nutritional parameters such as total
protein. CONCLUSION: No significant changes were observed in the general condition of elderly
patients, with the exception of a positive increase in fecal weight, by 30-d supplementation of a liquid dietcontaining cellulose and lafinose.
6

Latest Research
Suppressive effect of Citrus Aurantium against body fat accumulation and its safety.
Kazuhiro Kubo (Division of Food Science)
In Japan, Citrus aurantium (CA) is known as a kind of orange (dai-dai), which has been used for a
specific ornament on the New Year’s Day and also for herbal medicine. Citrus, an old name of lemon
tree, means a kind of oranges, and Aurantium means orange-yellow in Latin. CA is also called as “sourorange” or “bitter orange”. CA is now popularly used as an ingredient of many ephedra-free supplements
for dieting. The active constituent of CA is considered to be synephrine, and its suppressive effectagainst body fat accumulation is thought to occur through β-adrenergic receptors. Receptors, locatedon/inside cell membrane, change the cell functions in response to the external factors (e.g. hormone,light). Likewise, adrenergic receptors become activated by the binding of adrenaline or noradrenalin.
There are two types of adrenergic receptors; one is α-receptor that basically brings excitatory effects
and the other is β-receptor that brings suppressive effects. These receptors further can be divided into
α1, α2, β1, β2 and β3, each of which has various effects. .
Studies on the associations between β-adrenergic receptors and lipolysis have been reported mostly
by examining the white adipose cells of mammals. Of which, it is also explored that β3-adrenergic
receptor strongly promotes lipolysis and thermogenesis. Synephrine, which is an active constituent ofCA, is said to stimulate and activate β3-adrenergic receptor. Because of its suppressive effect against
body fat accumulation, Synephrine is used in many diet products.
Synephrine
One study reported that in humans a suppressive effect against
β-adrenergic receptors
body fat accumulation occurs when synephrine-containing CA istaken with other stimulants such as caffeine, but no other humanstudy has been done regarding the effect of synephrine on body
Fatty Acidfat accumulation. In this study, therefore, we focused on theTG
Fatty Acid
suppressive effects of synephrine-containing CA against body fat
accumulation and its safety in rats.
Adipose cells

Suppressive effect of Citrus Aurantium against body fat accumulation and its safety.
Journal of Clinical Biochemistry and Nutrition. 2005;36:11-17.
Kubo K, Kiyose C, Ogino S, Saito M.
Division of Food Science, National Institute of Health and Nutrition, Japan

Abstract:
A large number of so-called diet foods containing Citrus aurantium (CA) and its active constituent,
synephrine, for suppressing body fat accumulation are currently on the market. However, only one
human study has demonstrated the efficacy of CA, and its potential cardiotoxity has been reported in a
rat study. Therefore, we investigated the safety of CA and its suppressive effect against body fat
accumulation in rats. High fat (20% (w/w)) diets containing CA (synephrine content, 6.4%) at 0, 40, 200,
1000 and 5000mg/kg diet were fed to rats ad libitum for 79 days. For dieting, the recommended daily
intake of CA in many dietary supplements ranges from 100 to 1000mg/day, and the amount used in thisexperiment was approximately equivalent to 40 and/or 200mg/kg diet. In the 5000mg/kg CA group, theadrenaline and domamine concentrations in plasma were significantly higher, perirenal fat pad weight
was significantly lower, and body weight tended to be lower than in the control group. Although noabnormalities of serum clinical and biochemical parameters were observed except for adrenaline anddopamine, and also no histopathological abnormalities were evident in the heart, heart weight in the
5000mg/kg CA group was significantly lower than in the control group. Therefore, it is necessary to
examine more precisely the potential cardiotoxicity caused by excess intake of CA. Particularly, theelucidation of influences of the simultaneous intake of CA and some stimulants, such as caffeine, awaits
further characterization.
7

Latest Research
Activities of DGAT in the liver, with respect to intra-abdominal obesity and steatosis
Tomomi Yamazaki (Division of Clinical Nutrition)
In the liver, Triglyceride (TG) is synthesized and its excessive accumulation could lead to steatosis. The
synthesized TG is either stored in cytoplasmic droplets or secreted as very low density lipoprotein(VLDL) particles. Acyl-CoA:diacylglycerol acyltransferases (DGATs) is a membrane-bound enzyme thatcatalyzes the last step in triglyceride (TG) synthesis. Classified by detergent sensitivity, two types of
DGATs in microsomes have been proposed: the overt type (on the cytosol) catalyzes the synthesis of
TG destined for cytoplasmic droplets, and latent type (on the lumen of endoplasmic reticulum (ER))
catalyzes the synthesis of TG for VLDL formation.
There are two types of DGAT enzyme; DGAT1 and DGAT2, which are unrelated proteins that exhibit
DGAT activity. In order to elucidate the roles of DGAT1 and DGAT2 in the liver, especially in the overt
and latent DGAT activities, we created liver DGAT1- and DGAT2-overexpressing mice byadenovirus-mediated gene transfection, and then their phenotypes were investigated.
DGAT1-overexpressing mice had increased latent DGAT activity and a dilated ER, whereas thesechanges were not observed in DGAT2-overexpressing mice. As expected from the increased latent
DGAT activity in DGAT1-overexpressing mice, VLDL
secretion and particle size were increased, resulting
Liverin increased gonadal fat mass expressing a large
amount of VLDLR. This finding highlights the
Lipid droplet
importance of the VLDLR in the etiology of some
types of obesity, that is, intra-abdominal obesity.
In conclusion, our findings suggest that it would
While adiposebepossible to prevent obesity and steatosis by
tissue↑suppressing the activity of DGAT1 and DGAT2
respectively. It is therefore recommended toestablish dietary management to control the
Figure. Activities of DGAT1 and DGAT2,
and increased fat mass
activities of DGAT so as to maintain good health.

Increased very low density lipoprotein secretion and gonadal fat mass in miceoverexpressing liver DGAT1.
Journal of Biomedical Chemistry, 2005 Jun 3;280(22):21506-14
Tomomi Yamazaki1), Eriko Sasaki1), Chihaya Kakinuma2), Takashi Yano2), Shinji Miura1) andOsamu Ezaki1)
1) Department of Clinical Nutrition, National Institute of Health and Nutrition, Tokyo, Japan
2) Mochida Pharmaceutical Company Limited, Shizuoka, Japan

Abstract: Acyl-CoA:diacylglycerol acyltransferases (DGATs) catalyze the last step in triglyceride (TG)synthesis. The genes for two DGAT enzymes, DGAT1 and DGAT2, have been identified. To examine
the roles of liver DGAT1 and DGAT2 in TG synthesis and very low density lipoprotein (VLDL) secretion,
liver DGAT1- and DGAT2-overexpressing mice were created by adenovirus-mediated gene transfection.
DGAT1-overexpressing mice had markedly increased DGAT activity in the presence of thepermeabilizing agent alamethicin. This suggests that DGAT1 possesses latent DGAT activity on thelumen of the endoplasmic reticulum. DGAT1-overexpressing mice showed increased VLDL secretion,
resulting in increased gonadal (epididymal or parametrial) fat mass but not subcutaneous fat mass. The
VLDL-mediated increase in gonadal fat mass might be due to the 4-fold greater expression of the VLDL
receptor protein in gonadal fat than in subcutaneous fat. DGAT2-overexpressing mice had increased
liver TG content, but VLDL secretion was not affected. These results indicate that DGAT1 but not
DGAT2 has a role in VLDL synthesis and that increased plasma VLDL concentrations may promote
obesity, whereas increased DGAT2 activity has a role in steatosis.
8