AF is a disease of civilization. Get uncivilized!!

That's really what it comes down to. Over millions of years the human body's systems were perfected in harmony with its natural nutrient environment, and then came the agricultural/ industrial/ manufacturing revolutions. So here we are, doing our best to be healthy civilized with uncivilized bodies.

A most incredible event some 73 +/- thousand years ago very nearly put an end to human existence when the 'supervolcano' Toba* in Indonesia erupted. It's estimated that as few as several thousand people survived to carry on, most likely somewhere in Central Africa. It's been a fascinating experience to read about all this in George Weber's masterful website** and to relate it all to our current nutritional dilemma, especially why we like salt so much when too much is poison. We evolved on as little as 768 mg/day of sodium, which along with 10,500 mg/day of potassium makes for a 14:1 K/Na ratio.***

That near-annihilation of our species had the effect of making us more genetically similar than would otherwise have been the case. The small amount of initial variation in mitochondrial DNA has allowed tracking of migrations that ultimately populated the entire globe.

Be well everybody
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*Supervolcano: [en.wikipedia.org]. Toba catastrophy theory: [en.wikipedia.org]

**Toba Volcano: [www.andaman.org]. From Chapter 5: "It has been estimated that only 40 to 600 females (which translates into a total population of less than 3,000 persons; Harpending H.C. et al. 1993) came through the bottleneck. Another estimate arrived at 500 to 3,000 females (ref. Rogers A.R. 1993) and yet another at 1,000 to 4,300 individuals (Ayala F.J. 1996; Takahata N. at al. 1995). The highest estimate so far has 10,000 females of reproductive age as the minimum (ref. Ambrose S.H.. 1998). Even if the highest estimate is accepted, we are talking about the entire human race numbering no more than the population of one small country town today".

***Paleolithic nutrition revisited: A twelve-year retrospective on its nature and implications. (Table 3): [www.nature.com]

Get uncivilized!! continues with this excerpt from George Weber's Toba Volcano, Chapter 5, Through the Bottleneck:

1. A most peculiar mammal: Homo sapiens

Human beings, in civilizations that think about such things, pride themselves on their (occasionally) towering intelligence, their scientific, technological, philosophical, economic and artistic accomplishments. Scientific nomenclature knows humans as Homo sapiens ("wise man") which nicely reflects the high self-esteem characteristic of the species.

Leaving the towering but hard-to-measure intelligence aside, there are other, much more easily measured if rather less well-publicised aspects of Homo sapiens that set off the species quite spectacularly from other life forms on earth:

Of all living things on earth weighing more than a few grams or ounces,

(a) Homo sapiens is today the only truly world-wide species, living in flat and rugged, in hot and cold, in dry and wet, in high and in low places, and practically everywhere in between. The species has recently even managed to gain a foothold in Antarctica and gone for a walk on the moon. In large cities the species has also created its own environment, something no other large animal has done.

(b) Homo sapiens has by far the largest numbers of individuals (estimated 6,300,000,000 in 2003) of any large species

(c) Local variations (known as "races") also show extraordinarily low levels of within- and between- population genetic variation in comparison to the nearest relatives, the apes. This odd fact supports an extremely recent origin for Homo sapiens (ref. Ferris et al., 1981; Ruvolo et al., 1993). Only around 10% of the limited human genetic variation is accounted for by differences between populations (ref. Lewontin, 1972; Relethford, 1995).

(d) Homo sapiens has very little genetic diversity despite its huge numbers.

The last point is the oddest - and the least widely known. It is also one of the arguments in favour of a relatively recent bottleneck (e.g. Toba) rather than one much longer ago (e.g. one proposed for 2 million years ago by the "regional continuity" supporters (ref. Hawks, et al, 2000). The low genetic diversity implies that the present teeming multitude of human beings trace back to a numerically tiny and relatively recent founding population.

A geneticist had this to say on Homo sapiens:

... we have sequenced 10 kb of non-coding DNA in a region of low recombination at Xq13.3 from 70 humans representing all major language groups of the world. In addition, the same sequence has been determined from 30 chimpanzees, representing all major subspecies, as well as bonobos. Comparison to humans reveals an almost four-fold higher diversity and a three-fold greater age of the most recent common ancestor of the chimpanzee sequences. Phylogenetic analyses show the sequences from the different chimpanzee subspecies to be intermixed ... These data, as well as preliminary work in the other great apes, indicate that the human genome is unique in carrying extremely little nucleotide diversity. (ref. Kaessman H. et al, 2000)

While human overall genetic diversity is low, what diversity exists, is highest in Africa. This fact is one of the major arguments in favour of the "Out of Africa" theory of human origins:

... the gene pool in Africa contains more variation than elsewhere, and the genetic variation found outside of Africa represents only a subset of that found within the African continent. From a genetic perspective, all humans are therefore Africans, either residing in Africa or in recent exile. (ref. Pääbo S., 2001)
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(continue at [www.andaman.org])

Erling - Another brilliant contribution! Thanks for sharing the results of your many hours of research on this topic, the facts of which are often mis-stated. I look forward to spending time reading at your links.

You aren't the only one who says civilization is at the root of our health issues... but this is especially enlightening.

Jackie

Thanks Hans, good to have this pared down to what belongs. Perhaps George Weber's delightful Acknowledgments will also survive:


"Sincere thanks to all the authors listed in the References and to all those that have worked, are working and will work in the field - as long as they publish their results.

Many thanks to all the scientists and their publishers (among which my compulsory weekly reading Nature figures foremost) whose drawings, charts, photographs, data, arguments and ideas I have used and sometimes adapted to the requirements of the Internet where this article is published exclusively. Wherever possible, the source for materials used is given so that the scientific labourers and their publishers do not feel left out or cheated.

I hope that many readers will follow up and go back to the sources that have fed this article. There is plenty more there to draw from.

A special thanks to Tim Gillin of Australia for his original thinking and his ideas. It was Tim who about 2 years ago in all innocence started me off on what I have come to think of as "the Toba trip". I have often cursed him for it, but now that it is done, I feel mostly grateful.

My gratitude also goes to the ladies of the Kantonsbibliothek Baselland at Liestal, Switzerland, for invariably filling even the most outlandish request for article reprints. It can't have been easy.

And last but not least, a great big kiss to my wife Eloi in gratitude for all she has had to put up with while my head has been on Toba She has had to put up with quite a lot, I can tell you!

Needless to say, I alone remain responsible for what I have written here. Blame me for it, but be kind and merciful even in your wrath.

George Weber
THE ANDAMAN ASSOCIATION