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Category: Medical

Lifespan: Why We Age – and Why We Don’t Have to

This is one of the books I recently read and found most interesting. The title is Lifespan: Why We Age-and Why We Don’t Have to. Unfortunately, the Japanese translation has not been published yet, so I listened to it in the English version of Audible.

Why do people age? What is aging?

Even in 2020, the reasons and mechanisms of aging are not fully understood. Aging is an unavoidable event for most people on the planet, and it is natural for them to age and eventually, die.

On the other hand, this book states that “aging is a disease and is a disease that can be dealt with.” If you look at this particular sentence, it sounds like a commercial of a suspicious health product, but the author David Sinclair is a genuine biologist and co-founder of a bio-venture. By the way, I became aware of the existence of Sinclair’s books because of his guest appearance on the podcast that I always listen to.

The points mentioned in this book, along with the scientific evidence, are:

  • Yeast and human cells behave similarly (this is why many Nobel prize winners come from yeast researchers).
  • Sir2 (sirtuin gene) is found to be significantly involved in longevity in yeast.
  • Deletion of Sir2 shortens lifespan, and activation increases lifespan of yeast. (However, some observations deny this fact.)
  • Sir2 is activated by hunger and calorie restriction.
  • The easiest ways to extend human life are proper diet, moderate exercise, and sauna.
  • Sir2, a longevity gene, is activated by dietary restriction and exercise.
  • Sauna generates stress that promotes Sir2 activation when combined with a water bath.

Until now, medical treatment in which humans have spent a great deal of time on research is merely responding to individual diseases, and we have not invested time in research of aging which causes all diseases, according to this book.

As is often said, the probability that a child will get cancer is almost zero. However, due to foods containing additives, radiation falling on the earth, and the effects of stress, the epigenome that determines the function of genes changes with age, and as a result, normal cells become cells that can cause various diseases.

Every day, the human body undergoes an enormous amount of DNA damage, and the body has the ability to repair it. However, as DNA damage increases and repairs cannot keep up, mistakes in DNA replication begin to occur. The substance produced by this replication error is called ERC, and it is thought that the accumulation of ERC leads to aging. Sir2 prevents the formation of this ERC.

Research on ERC and Sir2 seems to be in a state of inactivity as far as this book is concerned. This is because conducting research on diseases that are already prominent is likely to yield short-term returns both academically and business-wise. Because longevity is difficult to set as an indicator of what is to be achieved, it is understandable that research does not progress easily.

As this book repeatedly states, almost all diseases are caused by aging. If you can keep your body condition, the state of the epigenome to be precise, as it was when you were born, you should not be sick except for congenital ones. And if aging itself is regarded as one of the diseases, it should be possible to slow down or stop the progress.

Whether you consider delaying and stopping aging as the world of science fiction or something that can be realized by making use of the knowledge and technologies largely depends on the values ​​of each person. I always want to be the latter.


最近読んだ書籍の中で特に興味深かったものを紹介します。タイトルは Lifespan: Why We Age – and Why We Don’t Have to 。残念ながら日本語訳はまだ出版されてないようですが、自分は英語版のAudibleで聴きました。



一方で、本書では「老化とは病気である。そして対処可能な病気である。」と明言しています。ここだけ見れば、なんだか怪しい健康商品の宣伝っぽいですが、著者のDavid Sinclair氏は正真正銘の生物学者で、バイオ・ベンチャーの共同設立者でもあります。ちなみに、自分がSinclair氏の書籍の存在を知ったのは、いつも聴いているポッドキャストに同氏がゲスト出演したことがきっかけでした。


  • イースト菌と人間の細胞は振る舞いが似ている(多くのノーベル賞受賞者がイースト菌の研究者から出ているのはこのため)
  • イースト菌でSir2(サーチュイン遺伝子)が寿命に大きく関与していることが発見される
  • Sir2を欠損させると寿命が短縮し、活性化すると寿命が伸びることがイースト菌で観測される(ただし、この事実を否定する観測結果もある)
  • Sir2は飢餓やカロリー制限によって活性化される
  • 人で実践できる最も簡単な長寿化は適切な食事制限、適度な運動、サウナである
  • 食事制限や運動によって長寿遺伝子であるSir2が活性化される
  • サウナは水風呂と組み合わせることでSir2活性化を促すストレスを発生させる







a16z Podcast: Taking the Pulse on Bio

As a CEO of digital health startup, I could not miss this one.

Bioengineering can also benefit from unsupervised learning approach as discussed in another a16z podcast by letting AI show us the unique features that lead to a theory (or CRISPER) rather than having a human ‘guess’ it. There is no doubt that quantum computing will play an important role here in the near future.

I’m 100% certain that new type of entrepreneur who understands both bioengineering and computer science (perhaps, quantum computing) will attract so much attention from VCs as a bio industry needs this kind of talent.

Well, I gotta go back to college and study bioengineering again. :)