Here's the long and the short of it: The body knows how to be young. It knows how to be old. The body can be any age it decides to be.
The body doen't wear out like an old car or a washing machine with leaky gaskets. The life cycle is programmed into us. When you're 2 you have growth hormones through the roof, and when you're 13 your sex hormones flare up and when you're 60 your body dials up inflammation and programmed cell death. At the same time, your body is gradually shutting down your immune system and turning off the antioxidant defenses. Eventually it kills you. If the 'gators don't getcha then the 'skeeters will.
The whole process is coordinated by signal molecules in the blood. What signal molecules? Wouldn't we all like to know1 Researchers (including several people I know) are homing in on the answer, and we may have an intravenous fountain of youth a few years down the road. Or maybe not. Removing bad actors from the blood will be just as important as adding youthful signals.
How do we know aging is something the body does to itself, deliberately? There's a lot of evidence, and I've spelled it out in a book. (Two books actually, one for biology researchers , and one for everyone else .) Here's a sample:
- Aging is in our genes. In fact, there are genes that can be deleted from some animals by genetic engineering, and they live much longer. These can only be called "aging genes".
- These genes are closely related across the animal kingdom. The genes that control aging in lab worms are close to the genes that control aging in you and me.
- This means that evolution has kept aging genes around for at least half a billion years. They're no mistake. Evolution is holding on to aging for a reason.
- If the body were trying to live as long as possible, then it would succeed best when it had all the resource it needs and few demands. Eating a lot and not exercising would be a key to a long life. But we all know the opposite is true. Animals live a whole lot longer when they're starved half to death and exercising vigorously.
If the body can extend its life when it's starving, it could do the same thing when it had enough food, if it wanted to. This is one way we know that the body doesn't want to live beyond its appointed time.
Why doesn't my doctor tell me this?
It's a very legitimate question, and it doesn't have a simple answer. The reasons can be traced to the culture of science.
Ever since the mid-1960s, "natural medicine" has been in vogue. "Nature knows more than we know." "Help the body to do better what it is already doing well." There is no place within this viewpoint for the fact that what the body is "doing well" is killing itself. Doctors have trouble making sense of this. Maybe you can understand why.
There has also been dogmatism in the evolutionary biology community. Evolutionary theorists are particularly closed-minded and defensive, in part because they've been under attack by fundamentalist Christians. In this same time frame -- the mid 1960s -- evolutionary biology adopted the idea of the "selfish gene". This, in fact, is a very narrow way to look at the diverse and surprising modes of natural selection. But for 40 years, it became common in the field to say that there is really no such thing as cooperation, and all of evolution can be explained as the selfish behaviors of individual genes. So when evidence turned up that there are "aging genes" -- genes that have no other purpose than to slowly kill the individual who carries them -- the theorists ridiculed the idea. "We know this is wrong. You must be mistaken. Go back to your lab and look again." The problem is that death is programmed into our genes for the sake of the community, not the individual, and evolutionary theory has gone through a dark age in which they refuse to recognize that there are communities with evolvable interests apart from the individuals that make up the community.
Of course, the way science ought to work is that the theorists listen to the experimentalists, and they design their theories around the lab results. This is most true in biology, where life is complicated and theories all have their exceptions. But in this case, the theorists were waving their equations around as though they could tell the lab researchers, "what you are finding cannot be real."
Now that I understand aging, what does that do for me?
Understand that the diseases of old age are different from the diseases of youth. If you optimize your nutrients, get lots of exercise, avoid toxins and infections, get enough sleep -- that is probably all you need to be a healthy young person. But the diseases of age are different. We need various tricks to slow down the body's headlong rush into self-destruction. Fasting is the best trick I know. Avoid sugar and cut back carbohydrates. Eat less meat or none. A few hormones can help (metformin, DHEA). Anti-inflammatories (fish oil, aspirin, turmeric extract) are central. Anti-oxidants are a not a good idea for the most part, but glutathione is the exception (also NAC, from which glutathione is made). Vitamin D and Mg, and Zn supplements are good no matter what your age.
Few people are aware of the most powerful thing that one can do to extend life expectancy: Loving connections with family, leadership in the community, open-hearted social relations -- an engaged, connected life style is more important for longevity than cholesterol or blood pressure or even blood sugar levels.
There's a lot more detail at my web page, AgingAdvice.org.