人為什麼會變老? 由第一道皺紋開始嗎?
日本作家村上春樹曾說：「我一直以為人是慢慢變老的，其實不是，人是一瞬間變老的。」 人變老，不是從皺紋或白髮開始，我們的衰老是從不理會自己健康那一天開始的。
生老病死，是人生必經之道。以往我們對衰老的態度是既來之，則安之。不是我們不想活得久一點，須知尋求長生不老，幾千年前的秦始皇已有古典記載。隨著我們對醫學和科學的認識日漸精進，我們已對衰老的原因有更深的認識。
現今醫學的研究發現衰老是由多種原因導致。我們粗略可以分開為兩大理論︰
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1) 破壞理論 我們呼吸時，細胞的線粒體Mitochondria將食物氧化分解並產生能量(以三磷酸腺苷ATP的形式儲存)，並且產生代謝產物．這些代謝產物包括了Reactive oxygen species (ROS)，ROS能積聚並對細胞DNA造成破壞。久而久之，細胞漸漸失去功能，就算還有修補能力，也不能回復以前的狀況，繼而導致崩壞、衰老、死亡。 |
2) 遺傳理論 我們發現在DNA藍圖裡有好幾種遺傳基因genes能決定我們人類的衰老狀況，這些基因控制著我們體內一種叫Sirtuins酵素的多寡。Sirtuins是麻省理工生物學教授Leonard P. Guarente在1991首次研究酵母菌細胞發掘出來的。其後我們發現秀麗隱桿線蟲有4種Sirtuins，黑腹果蠅有5種，而所有哺乳類動物包括我們人類有7種(SIRT1-7)。如果我們能全力增加Sirtuins 的工作潛能，發現酵母菌的壽命能增加30%，而果蠅實驗能增加其壽命至57%。研究發現， Sirtuins (SIRT1-7) 控制了幾乎人身體內所有組織的新陳代謝，能改變衰老引致的心血管病，癌病，腦退化，代謝病，關節炎及骨質疏鬆。 |
衰老帶來的健康問題很多，包括各類癌病，代謝病(肥胖，高血脂，糖尿)，腦功能衰退（認知障礙），心臟病（動脈粥樣硬化），視力聽力變差，肌肉體力轉弱，外觀難看（皮膚皺紋和鬆弛，頭髮全白），腦力全轉差了（智力和記憶力），關節炎困擾等等。在先進國家裏，9成的死亡人數都是跟衰老引致的毛病有關連的。
要對抗衰老，應該在年輕時就準備了。但儘管你已年達80，今天才開始抗衰老並不為遲。
Why do we age?
To be able to live longer and healthier is something we all long for. We all go through aging. Ironically, as a kid, we all want to grow up faster; but as we past middle age, we all want to grow old slower. If money can buy back youth, it must be the most sought after commodity in this world.
As science advances, we begin to understand more about why we age. There are numerous theories about aging. Here are 2 very important ones.
- Our body cells contain organelles known as mitochondria. They are the power houses that produce Adenosine Triphosphate (ATP) by metabolism. ATPs are the energy units that allow us to do all sorts of activities. Every single cell will rely on ATP to function normally. However, this metabolic process also produces reactive oxygen species (ROS) as a by-product, which can damage our DNA. Over time the damage accumulates to the extent that our cells are no longer able to repair themselves, leading eventually to cell death.
- In our DNA blueprint, we discover there are several genes that dictate how we age with time. They are called Sirtuins, first discovered by Professor Leonard P. Guarente of MIT in 1991. Caenorhabditis elegans ( a kind of roungworm) has 4 types of sirtuins, Drosophila (a kind of fruit fly) has 5. By activating the expression of these genes, we are able to increase the lifespan of yeast and Drosophila by 30% and 57% respectively. We humans and other mammals have 7 distinct types of sirtuins. Sirtuins control almost all aspects of metabolism, and can change the way and rate we age.