米田幸雄　Yukio Yoneda Ph.D.

　医薬品は重篤な発作や不快な症状を軽減する目的で使用されますが、医薬品投与で種々の症状が緩和されたのちは、生活習慣を改善することで次の発作や発症を防ぐのが基本的な考え方です。本来は症状を軽減するための一時的な使用に限局すべき化学物質ですが、実際には症状や発作の緩和後でも予防目的で、長期的に医薬品を投与する場合が頻繁に見受けられます。医薬品の有効成分は、基本的には新規に合成された化学物質なので、長期間にわたる投与の安全性は担保されていないのが実情です。それどころか、ときには一時的な投与の場合でも重篤な副作用が出現します。医薬品が「両刃の剣」といわれる所以です。今まで医薬品は、人類の平均寿命の延伸に大いに貢献して来たのは事実ですが、残念ながら健康寿命の延長に対する影響力はそれほど大きいとは言えません。一方、人類の歴史の中で安全性が担保された成分や食材が、食物や食品、あるいは飲料として日常的に摂取されてきたので、食品中成分の安全性は医薬品に比べてはるかに高いと思われます。現代社会で求められるのは、健康寿命と平均寿命の距離を短縮するアンチエイジング対策です。
　一方、医薬品の場合に比べて、健康食品の有効性に関する科学的根拠は極めて希薄であると言わざるを得ません。例えば、経口摂取された食物や食品は強酸性の胃液中で数時間以上滞留します。その後、消化酵素群の作用で低分子物質に分解されて小腸粘膜から吸収されないと、経口摂取後には血液中に成分は出現しません。基本的には、小腸粘膜から吸収された成分は門脈を経て肝臓に至り、その後心臓を経由して血流で初めて全身に配られます。肝臓は体内で最も大量の活性酸素を発生させる臓器ですが、血液中には内在性抗酸化物質のグルタチオンが極めて高濃度に存在しています。脳機能に対する有効性を確認するには、これらの関門をすべて通過して脳に到達する特性を証明することが求められる訳です。この基本的な食物吸収を考慮しない食品、健康食品、機能性表示食品あるいは特定保健用食品などが巷に溢れているのが現状です。食品類の有効性に関する基礎的研究が、医薬品の場合と同程度に発展および進化する必然性があると言えます。
　薬理学は今まで新規医薬品の発見と開発（＝創薬）を通じて、不快な症状の軽減や重篤発作の緩和を目指してきました。薬理学が人類の健康と福祉に大きく貢献してきたことは疑いのない事実ですが、医薬品が標的臓器や標的外臓器への副作用や毒性を示す危険性は常在しています。一時的な医薬品服用で突発的な不快症状を軽減してから、食品類の長期摂取を含む生活習慣の改善を図ることが、これからますます重要性と真実味を帯びてくると信じています。疾患を発症して不快症状を体験するよりも、生活習慣の改善を通じて症状の発症を予防することの方が、生活の質改善の観点から望ましいのは議論の余地がありません。安全性の高い食材や食品成分の機能性と有効性を、最新の科学技術を用いて学問的に証明することを目的として、この度予防薬理学研究所を設立する運びとなりました。研究者や学生の方々のみならず、広く一般市民の方々のご理解とご協力をお願い申し上げます。

Prolonged malfunctions of particular cellular molecules would sometimes lead to irreversible abnormalities and dysfunctions of cells, tissues and individuals, which are undoubtedly responsible for the consequential crisis of various symptoms and syndromes as particular diseases and disorders.

Pharmaceutical sciences have been dedicated to the discovery and subsequent development of innovative drugs useful for the therapy and treatment of patients suffering froma variety of these symptoms.

Validated evidence is absolutely required for the demonstration of beneficial effects of the acute administration of medicines and drugs on different syndromes and symptoms seen in patients, while they have no choice but to take drugs for mitigation of their unpleasant disabilities and conditions as quickly as possible even at the cost of inevitable untoward side effects sometimes highly toxic outside the target cells.This is the reason why drugs are often called as a “double edged sword”.

In contrast to drugs with inevitable side effects, edible foods have been often beneficial for the prophylaxis and/or alleviation of unpleasant conditions upon sustained daily intake from childhood in young to elderly people with particular health disturbances.

Foods are in principle derived from edible materials with guaranteed safety for people’s health for hundreds of years in human history unless quite excessive amounts are unbelievably consumed.

Although drugs are highly effective in inducing acute mitigation of unpleasant symptoms during the onset of diseases after a single oral administration for the therapy, chronic consumption is undoubtedly necessary for the appearance of alleviation of unpleasant functional disturbances with beneficial foods available
for the prophylaxis.

For patients suffering from severe symptoms of a particular disease, however, prophylaxis is sometimes much more important than therapy.

People do not have to suffer from heavily unpleasant conditions as long as they pay much attention to their life styles including daily food intake.

A tremendous number of edible foods and their ingredients have been used for the development of dietary supplements and nutraceuticals for many reasons in recent years, while their scientific background is considerably poor compared with drugs so far.

For example, edible active ingredients should be stable in the acidic gastric juice after oral intake, followed by cleavage with digestive enzymes for effective absorption from intestinal mucosal cells into the portal vein and subsequent hepatic metabolism before the appearance in circulating bloods for the delivery to target organs, tissues and cells.

They should be also excreted from the kidney after metabolism. However, this simple physiological mechanism is regrettably unclarified with numerous food-derived products on sale as a dietary supplement and/or nutraceutical in the market.

The poor scientific validation has been highly impairing the importance of prophylaxis of the onset of unpleasant disabilities and possible alleviation of particular symptoms in people taking
food-relevant products for health improvement.

It thus appears that nutraceutical sciences should be rapidly established in collaboration with pharmaceutical sciences for the purpose of maintenance of the health and welfare in human beings.

From this point of view, laboratory experiments are to be more critically and precisely done at least using molecular and cellular biological techniques with dietary supplements and nutraceuticals to provide qualified evidence for the clinical effectiveness and usefulness toward the prophylaxis and possible alleviation of a variety of unpleasant conditions in people without particular diseases diagnosed.

Both intervention and cohort studies are of course necessary for the establishment of nutraceutical sciences as seen with pharmaceutical sciences in the nearest future.

Reference: J Pharmacol Therap Forecast 1 (1) 1
（https://scienceforecastoa.com/Articles/JPTF-V1-E1-1001.pdf）

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