This article at the NYTimes was a really good read: So Big and Healthy Grandpa Wouldn’t Even Know You. This will probably be behind a pay wall soon, so I’ll snip some of the text:
Over the past 100 years, says one researcher, Robert W. Fogel of the University of Chicago, humans in the industrialized world have undergone “a form of evolution that is unique not only to humankind, but unique among the 7,000 or so generations of humans who have ever inhabited the earth.â€
The difference does not involve changes in genes, as far as is known, but changes in the human form. It shows up in several ways, from those that are well known and almost taken for granted, like greater heights and longer lives, to ones that are emerging only from comparisons of health records.
The biggest surprise emerging from the new studies is that many chronic ailments like heart disease, lung disease and arthritis are occurring an average of 10 to 25 years later than they used to. There is also less disability among older people today, according to a federal study that directly measures it. And that is not just because medical treatments like cataract surgery keep people functioning. Human bodies are simply not breaking down the way they did before.
Even the human mind seems improved. The average I.Q. has been increasing for decades, and at least one study found that a person’s chances of having dementia in old age appeared to have fallen in recent years.
The proposed reasons are as unexpected as the changes themselves. Improved medical care is only part of the explanation; studies suggest that the effects seem to have been set in motion by events early in life, even in the womb, that show up in middle and old age.
“What happens before the age of 2 has a permanent, lasting effect on your health, and that includes aging,†said Dr. David J. P. Barker, a professor of medicine at Oregon Health and Science University in Portland and a professor of epidemiology at the University of Southampton in England.
It is worth reading the full article, they go through some eye opening examples of life before modern nutrition and medicine.
One wonders how many other influences are in play. I’m particularly curious to see if they have looked into epigenetic trends here as well. What the hell is epigenetics? From Ghost in the Genes, BBC’s excellent Horizon show on epigenetics:
Biology stands on the brink of a shift in the understanding of inheritance. The discovery of epigenetics – hidden influences upon the genes – could affect every aspect of our lives. At the heart of this new field is a simple but contentious idea – that genes have a ‘memory’. That the lives of your grandparents – the air they breathed, the food they ate, even the things they saw – can directly affect you, decades later, despite your never experiencing these things yourself. And that what you do in your lifetime could in turn affect your grandchildren.
Of course, we seem to be discovering new things all the time: Scientists Say They’ve Found a Code Beyond Genetics in DNA. This opens up more questions – How many more influences on our health have we not yet discovered?