Trace Nutrients Research 26 : 109112 (2009)

Case Study

Supplementary Effect of Oyster Extract on Depressed Patients under
Treatment with Antidepressants (2nd Report)
Takeshi NISHIGORI1$and Yoshikazu MATSUDA2$
1$
Wakeno Hospital, Osaka 534, Japan, '2$
Japan Clinic Co., Ltd., Kyoto 616, Japan ''Summary
We examined the clinical effects of a new type of oyster extract with a zinc concentration three times higher than thatof a previously tested sample (made by Japan Clinic Co., Ltd.) on 4 depressed patients and 6 normal control subjects.
Doses of up to 3 tablets of this new oyster extract were administered to depressed patients for 6 to 10 days with or without antidepressants. We found that the clinical effects of the new oyster extract were almost the same as those of theprevious one. However, from a clinical point of view, the fact that the new oyster extract requires smaller doses has aneconomic benefit. The zinc component of oyster extract is considered to play a major role in improving depression.

Introduction

Materials and Methods

Following on from previous studies13$, we administered aDoses of up to 3 tablets of the new type of oyster extract

new type of oyster extract with a zinc concentration about

were administered without dosage modification for antide-

three times higher than that of a previously tested sample

pressants for 6 to 10 days to 4 depressive patients#%!& =(made by Japan Clinic Co., Ltd. ; see Table 1) to subjects

0 : 4 ; mean age = 73 years ; diagnosed with depressive

including 4 depressed patients in order to observe its sup-neurosis, major depression, or bipolar disorder using theplementary effects in combination with antidepressants.

DSM-III diagnostic criteria ). One subject with depressive

An outline of the supplementary effects of oyster ex-neurosis was administered oyster extract only.

tract has already been provided in a previous report3$;

The dose of oyster extract was adjusted gradually fromtherefore, this new clinical trial was undertaken to confirm

1 tablet per day to 3 tablets per day. The dose of three tab-if the same supplementary effect occurred by the admini-lets per day was administered for 2-3 days, and was thenstration of 3 tablets of a new type of oyster extract per day

tapered to 1 tablet per day within 6 days. For one subject

to depressed patients. Furthermore, adverse effects of thewith depressive neurosis, 3 tablets per day were adminis-

new type of oyster extract and its clinical effects on nor-

tered for 10 days from the beginning to the end of the trial

mal control subjects were examined.

without any additional medicament.
Table 1 Composition of oyster extract

P r e v io u s ty p e

N ew ty p e

28.1

28.3

Protein (g/100 g)
Fat (g/100 g)

2.0

2.0

Ash (g/100 g)

15.4

15.8
48.5

Carbohydrate (g/100 g)

49.1

Fiber (g/100 g)

1.5

1.5

Zinc (mg/100 g)

37.7

150.0

Taurine (g/100 g)

5.5

5.4

250 mg of oyster extract is present in each tablet.
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Address : Higashinoda 551, Miyakojima-ku, Osaka, 5340024, Japan''Address : Kai-nichi 101, Uzumasa Ukyo-ku, Kyoto, 6168555, Japan'! 109 !

Sleeping pills were administered in combination withthermore, she became depressed at the news of the deaths

the antidepressants (tricyclic antidepressants). For 3 sub-of neighbors and old friends. She felt guilty because she

jects, (the exception being a subject with bipolar disorder),had outlived these people.

4#the self-rating depression scale (SDS) test was performed

She took 3 tablets per day from the beginning of thetrial. She exhibited improved symptoms by the third day.

before and after the trial.
Six normal control subjects"%!&$2 : 4 ; mean age =After 10 days of the trial, she could poetize without diffi-48 years) were initially administered with 1 tablet per day.

culty and was able to receive many guests with ease. AtThis was then increased to 3 tablets per day for a period of

this stage, her SDS scale score was from 34 to 36.

2 days, following by tapering of the dose to 1 tablet per

Case 2day within 6 days.

Housewife, 61 years old. Her husband had undergone aThe subjects described their impressions and feelings

surgical operation for pancreatic cancer and she now had

during the trial in letters and discussions. This trial wasdifficulty cooking for him (he needed to follow a special

carried out in a manner that ensured confidentiality fordiet). She placed great importance on the wellbeing of her

the participants and was in accordance with the Declara-

husband. She was melancholic every spring and autumn.

tion of Helsinki regarding the use of human subjects in

She was in a poor condition at the time of the trial

medical experiments.

(autumn). She was being treated with a moderate dosageof tricyclic antidepressants and sleeping pills. She initially

Results

took 1 tablet per day and then her dosage was gradually
increased to 3 tablets per day. Three tablets were adminis-

Increased energy levels were observed in all subjects

tered for 2 days. Her symptoms improved within a few

within a few days. This improvement continued duringdays and she spent the 6 days of the trial tirelessly. She

the period of the clinical trial. After the trials, no rebound

was no longer pessimistic and enjoyed her daily domestic

phenomena were observed.

duties. She expressed her thanks to us. Her SDS scale

One subject with bipolar disorder entered a manic statescore was from 43 to 34.

after just 6 days of administration of the oyster extract

Case 3with antidepressants. The presence of a depressive, mel-Widow, 71 years old. She has two sons, but they live

ancholic mood diminished markedly in all cases, and disap-

apart from her. She attended hospital as an outpatient.

peared for one subject with depressive neurosis during

When in a severely depressed state, she spent her days

the trial. With the exception of the one patient with bipolarwishing to go to her husbands side (who had passed away).

disorder, no troublesome adverse effects were observed in

She had been treated with a moderate dosage of tricyclic

the patients and the normal control subjects.

antidepressants for a number of years without success

The normal control subjects mainly described feelings

and had been unable to enjoy cooking for a long time.

of increased energy or the disappearance of fatigue. In

She initially took 1 tablet per day, which was graduallycontrast to the reactions to the previous type of extract, noincreased to 3 tablets per day. During the 6 days of theadverse reactions were observed in the normal control

trial, her symptoms improved and she became cheerfulsubjects.

and in good humor. Her SDS scale score was from 30 to 25.

To indicate the effects of the oyster extract more clearly

Case 4and precisely, we provide a summary of the background

Widow, 72 years old. She had divorced three times andand study findings for 8 subjects : 4 (Nos. 1-4) were admin-

was childless. She had suffered from bipolar affective dis-

istered the new type of extract, 4 (Nos. 5-8) were adminis-

order for many years, and suffered from slight depression

tered the previous type.

prior to the trial. She took a small dose of tricyclic antide-

Case 1

pressants and sleeping pills as an inpatient of a hospital.

Widow, 87 years old. She lives separately from her sons

She initially took 1 tablet per day, which was graduallyfamily. She frequently complained of sleep disturbanceincreased to 3 tablets per day for a period of 2 days. Theand depression. She took Triazolam for a long time to in-dose was then decreased to 1 tablet over 6 days. Just as

duce sleep, but was nonetheless unable to sleep well. She

the trial was over, she left the hospital without permission.

enjoyed poetizing, but had recently been worried about

Afterwards, she explained that she had left to meet her

her dimished capacity to do this. She had an assigned

last husband (although she did not know where he lived).

workload to be completed each month, although she wasFurthermore, she asked her doctor to return some money

hesitant to continue to participate in this program. Fur-

that she had borrowed from another inpatient.

! 110 !

Discussion

Case 5
Housewife, 54 years old. She had no physical symptoms.
She was experiencing her first depressive episode, with

Although the number of cases in this study is small, ourmajor complaints of severe loss of energy and appetite, as

results suggest that this new type of oyster extract has al-well as insomnia. It was determined that she should receive

most the same supplementary anti-depressive effects on

drug therapy and psychotherapy in hospital as soon as

depressed elderly female patients as the previous type.

possible. She was given 10 tablets of oyster extract per

However, more cases will need to be studied to confirm

day with antidepressants and sleeping pills. Her symp-

our results. To investigate the relationship between thistoms improved the next day, and her depressive mood had

effect and the gender and age of subjects, more male anddisappeared entirely. She requested to leave the hospital

young subjects will have to be examined.
It is worthy of special mention that a melancholic, de-and did so within a week.
Case 6

pressive mood was alleviated in all cases, and in one sub-Housewife, 35 years old. She had attempted to commit

ject with depressive neurosis, this oyster extract had asuicide by inhaling gas while in a severely depressive state.

marked antidepressant effect without the simultaneous

She failed, but accidentally started a fire in the attempt.

use of anti-depressive medicaments. However, the adverse

Her first daughter perished in the fire and her second

reaction that involved a subject entering a manic state will

daughter received burns over her entire body, while thehave to be considered in future trials.

woman herself was not injured. As a result, she felt ex-

The smaller number of tablets required for the new type

treme guilt. She was administered strong anti-depressiveof oyster extract to improve the depressive state is also

drugs and underwent intensive psychotherapy on a daily

beneficial compared with the previous type from an economic

basis, but her symptoms did not improve.

viewpoint. Finally, in view of the anti-depressive effect ofIn the trial, she was administered 10 tablets of oyster ex-Taurine5, 6!, we consider that the main anti-depressive effecttract per day in addition to tricyclic antidepressants andof oyster extract originates from its zinc component79!.

sleeping pills. Around the third day of administration of

Notably, the main difference between the two types ofoyster extract, she exhibited a marked improvement inoyster extract is the concentration of zinc.

energy level, and took a walk in the hospital garden every

References

morning. However, this improvement did not persist, andseveral days later she was again spending almost all her

1!Kimura K, Kumura J, Nishigori T (1985) Clinical Effecttime in bed.
Case 7of Oyster Extract (Tablet) on Hebephrenic Schizophrenia. Trace Nutrients Research 2 : 153159.

A postgraduate student, 25 years old. He had sufferedfrom bipolar affective disorder since the age of 15. He had

2!Nishigori T, Uesugi T, Kamizawa T, Sasaoki T, Takashima

spent about half a year in a hypo-manic state and half aM, Nagai K, Kimura M, Itokawa Y, Kimura K (1986)

year in a sub-depressive state. While in the sub-depressive

Clinical Effect of Oyster Extract on Hebephrenic

state and under treatment with antidepressants and sleep-Schizophrenia and Zn and Cu Metabolism in It (2nd report). Trace Nutrients Research 3 : 7987.

ing pills, he was administered 10 tablets of oyster extract
each day. His symptoms improved within a few days and3!Nishigori T, Kimura K (1988) Supplementary Effect ofhe recommenced his studies. However, he gradually re-Oyster Extract on Depressed Patients under Treatment

turned to his original state.

with Antidepressants. Trace Nutrients Research 4 :Case 8203208.

A research worker, 48 years old. He had suffered from4!Zung WWK (1965) A Self-rating Depression Scale. ArchGen Psychiatry 12 : 6370.

bipolar affective disorder since the age of 20. His condition
had been satisfactory (so-called remission) during the pre-5!Davison AN, Kaczmarek LK (1971) Taurine  a Possible Neurotransmitter? Nature 234 : 107108.

vious 7 years. However, he was required to study andwork over 10 hours every day and had not taken a holiday

6!Whirley BK, Einat H (2008) Taurine trials in animal

for more than 4 years. As a result, he finally succumbed tomodels offer no support for anxiolytic, antidepressant or

his severe depressive state again. He took 5 tablets per

stimulant effects. Isr J Psychiatry Relat Sci 45 : 118.

day of oyster extract with no anti-depressive medicament

7!Maes M, Vandoolaeghe E, Neels H, Demedts, P,Wauters A, Meltzer HY, Altamura C and Desnyder R

for 1 week, but his symptoms did not improve.

(1997) Lower Serum Zinc in Major Depression Is a! 111 !

Sensitive Marker of Treatment Resistance and of theunipolar depression : a preliminary placebo-controlled

Immune/Inflammatory Response in That Illness. Biolstudy. Pol J Pharmacol 55 : 11431147.

Psychiatry 42 : 349358.

9!Nowak G, Szewczyk B, Plic A (2005) Zinc and Depres-8!Nowak G, Siwek M, Dudek D, Zieba A, Pilc A (2003) Effect!

of zinc supplementation on antidepressant therapy in! 112 !

sion. An update. Pharmacological Reports 57 : 713
718.