By David Marsh
(Originally published in Positive Health Magazine: May 2001, Issue 64)
Charles Darwin believed there were are two great controlling forces behind evolution: one was natural selection, the other the 'conditions of existence'. He saw natural selection as dependent on the conditions, so he considered the conditions as the most important of the two controlling forces [Reference 1 & Postscript].
FATTY ACIDS = FAT
Some are essential: some are not.
EFA's EXPLAINED
As the 19th century was the period of discovery and understanding of the proteins, the 20th & 21st will be known as the era of discovering and learning about the essential fatty acids, or lipids. For those not familiar with the essential lipid saga, here is a brief outline.
There are two types of fat found in the body, one is storage or saturated fat, the white blobs one sees in butchered meat. This is the sort of fat found bulging round many of today's waistlines. Storage fat is solid at room temperature, like grease or butter: whereas structural fat is liquid, like olive oil. Our bodies convert excess dietary energy to make storage fat which it can store somewhere, ready to be called upon as an energy reserve in hard times, when food is short.
The second type of fat is structural (or polyunsaturated) fat which is intracellular, invisible and can only be seen in tissues when stained and viewed through a microscope.
Unlike saturated fat the structural fats cannot be made by the body and have to be obtained in the diet. For this reason they are known as 'essential': and 'structural' because they help build tissue - cell walls, cell membranes and other cellular constructions, nerve cells: with proteins they build nearly everything.
As with the 'parent' essential amino-acids from which protein is made, structural fats (or lipids) have 'parent' fatty acids (only two, not 8 or 9 as with amino acids). These are known as 3 omega, and 6 omega. The parent 3 omega fatty acid, alpha-linolenic, is to be found in green leaves: and the parent 6 omega fatty acid, linoleic acid, is to be found in the oily part of seeds.
These 'structural' lipids are fluid: they have 'bendy-hinges' (double bonds) in their molecular structure, which give them elasticity. Storage fat has no double bonds which is why it is solid. The 3 omega parent has 3 double bonds, whilst the 6 omega parent has 2 double bonds.
Once ingested, the parent fatty acids are converted, slowly and somewhat laboriously by the body, into progressively more and more complicated molecules: 3 omega goes through five such stages of change, ending up as docosahexaenoic acid, DHA which proudly sports 6 bendy double bonds, making it unique in the spectrum of fatty acids. The ready-formed long chain 3 omega DHA is found predominanly in aquatic food sources, namely fish and shell fish.
6 omega goes through similar such changes [check] finally landing up as arachidonic acid: or AA. This long chain 6 omega is found in animal tissues, particularly in offal, liver, kidney, heart. It is essential for vascular tissue, and especially the placenta, which creates the new vascular system built to supply the fertilised egg / developing foetus with nutrient.
Both DHA and AA are 'neural lipids' which make up 60% of the human brain. DHA is used in synaptic junctions in the brain, in nervous tissue, and in the photoreceptor of the eye. 75% of foetal nutrition comprises guess what - DHA & AA), water, etc. Meanwhile, AA is as important for the vascular system.
To summarise: the human body can make the long-chain derivates AA and DHA, but it is a slow, not very efficient process. Those cultures traditionally using fish would get rich supplies of DHA, the end product of 3 omega, biosynthesis, 'oven-prepared' by the fish.
Some quite long chain lipids are to be found in certain blue green algae available today from health food shops and niche marketeers. Sources such as chlorella, spirulina, aphanizomenon flos aqae and duniella have promising nutrient spectrums: these can be useful for vegetarians or vegans [for further information see 2].
THE FIVE PHASES
Students of evolution rarely fail to be impressed when, examining each evolutionary epoch and its various phases, we find again and again that in every new epoch, when a new, more highly evolved lifeform becomes established, gathering itself for its future of dominance, the supporting 'conditions of existence' (to borrow Darwin's phrase for the environment) had always to be in place and functioning first: preparing for the dance of the DNA with the environment.
To see this more clearly we'll look at a few epochs of evolution: an epoch can be divided into five parts.
Phase One sees a rich nurturing environment supplying the right temperature, light, food and other basic living materials to small populations, which under such protective and stimulating conditions reproduce rapturously; populations thrive and grow successfully.
Phase Two is more of the same, but population numbers have increased.
Phase Three populations have increased considerably, to the point where there is a dwindling of food and resources per capita - any species or type which has extra abilities in capturing their necessities will succeed over less efficient types.
This carries on through Phase four, until its end, when an exhausted environment fails to supply the needs of hugely increased populations when even the best-fitted cannot survive.
Phase Five is Phase One of the new epoch, when different species, better-fitted to the new environmental matrix* become dominant (*the new chemistry is often brought about by the activites of the sheer numbers of the previously dominant species).
One of the earliest lifeforms, the blue-green algae, were the dominant lifeform for over two and half billion years. They produced oxygen as a by-product of photosynthesis, and over this time slowly oxygenated the planet. Equally importantly they produced proteins, carbohydrates and essential fatty acids - or lipids - which were rich in 3 omega including DHA. The Blue-Greens laid down the basic building blocks of life, which we rely on, now and for the foreseeable future.
So DHA played a huge role in the 2.5 billion years of early Blue-Green life. In their teeming zillions the blue-greens (some divide in to 4 every 28 hours) gradually oxygented the planet which had previously been without oxygen (anaerobic). When the oxygen level rose from 0% to 3% of today's oxygen levels, and oxygen began to be used to provide superior fuelling, animal life fairly whooshed into being in top gear. Within 500M years all the phyla - or branches of the animal family tree - were laid down, and evolution took off, with the creatures getting larger and larger until the age of the great reptiles, and of course the dear old dinosaurs.
Their 'conditions of life', or their environment, was a 'sine qua non' of their success. A vitally important part of these 'conditions' was an environment rich in DHA: a nutrient the landlocked foodchain does not have access to.
Over thousands of millions of years 'blue-green' activity, the environment of all living things was spectacularly rich in DHA. Fish and reptiles need omega 3 lipids for reproduction: they prospered for 1000's of millions of years cashing in on the billions of years of the blue-greens' exertions.
Now we take a great leap to the end of the Cretaceous period, roughly 70 million years ago when the dinosaurs disappeared, after which the mammals were to rise to dominance.
Here we can see a further example of the environmental mix coming first, before the evolutionary change actually happened, in the evolution of the placental mammals. For their evolution to be possible there had to be a widely available source of AA, the long chain 6 linoleic (see below) which became widely available only after the demise of the dinosaurs. Then a strange thing happened which no-one has yet managed to explain entirely.
In the terrible obliteration of most terrestrial animal life, when the dinos met their pitiful end, and some creatures retreated to flourish in the sea: most plant life changed from ferns and ginkos, to flowering and seed bearing plants and trees!
We have the giant meteorite theory, the 100,000 year period of intense volcanic acitivty theory and rare metal theories: but speculation also points to a giant sunflare dowsing the planet with solar storms and unsual clouds of radio or quantum activity which effected a genetic mutation - or was it a modification? - which suddenly produced seeds, a rich source of linoleic acid from which AA is made, biosynthetically by the animals that eat them.
Now AA is a vitally important part of the vascular system: the mammalian placenta is basically a new vascular system specially created to support the nutritional and other needs of the growing foetus. The mammalian explosion couldn't have happened without the AA from 6 linoleic: which, it's worth repeating, only became widely available when the flowering and seed bearing plants took centre stage [3].
Also from the family of the omega lipids come the long chain and very highly specialised prostaglandins and leukotrienes. Certain of these sophisticated biochemicals are so powerful they are 1000 times more powerful than histamine, the chemical that makes hay-fever sufferers sneeze. Their functions in mammals include regulating our blood flow, immune systems and reproductive processes [2].
Prostaglandins have been discovered to affect gene behaviour, or how the gene 'expresses' itself. This means it has the ability to make the (same) genetic structure (DNA, genome) behave in a different way. They have been been found to have the ability to affect the expression or viral genes, and in ammals to switch on muscle protein syntheses [2].
Here we have a link between genetic expression, diet and physical activity. The latter played a prominent role in our evolution: the results of lack of this highly biologically-desirable activity over only one or two generations is now being seen, sadly, in growing numbers of our children.
THE SAVANNAH PARADIGM
Mammals have bigger brains than fish and birds, and this is largely due to the vascular system of the placenta providing rich supplies of AA and DHA to the growing foetus.
However a riddle presented itself in the development and growth of the land mammals. As their bodies grew larger and larger, their brains became proportionately smaller. Also early hominids apart from homo erectus (our line) such as Australopethicus, an early savahannah dweller, had a far smaller brain than ours (less than half the size of modern brains), and they stayed the same size for some 3 million years, whereas homo erectus, which gave rise to homo sapiens, developed larger and more capable brains over a fraction of that time, a few hundred thousand years. Why?
For about three quarters of a century the perceived wisdom amongst scientists has been that our line of ancestors, Homo erectus, after emerging from the forests became savannah or plains dwellers, living on large mammals, roots, shoots and fruits. The challenges of life on the open plains, having to outwit large and dangerous animals, the climate, etc, was according to the old dogma, how our earliest ancestors learned to stand on two legs and developed their large brains.
This followed the discovery in the 1920's of 'Maung Child' in the Olduvai Gorge in S. Africa, by Raymond Dart, the anthropaleontologist from Witwatersrand University, South Africa, who was largely responsible for this scientific belief system or paradigm [4]. He went on to make other important paleonotological finds, and lectured and published widely. His story was written up by Robert Ardrey in his best-selling book "African Genesis" first published in 1961.
However in 1960 Sir Alistair Hardy from Oxford University, enlarging on the ideas of Max Westerhofer (published 1923), suggested that "some modern human anatomical features indicate an aquatic form of adaptation" [5]. Hardy floated the theory that when our forebears, homo erectus, emerged from the forests they became riverine, lacustrine or marine shore-dwellers [6].
Elaine Morgan, with Hardy's help, developed the idea in her books 'the Descent of Woman', 'the Aquatic Ape' [7] and 'the Scars of Evolution', creating the new paradigm of waters-edge evolution [8].
The theory is based on certain anatomical features that man shares with marine mammals (the cetaceans - whales, dolphins and porpoises) which are not found in other land mammals.
These include loss of body hair; a layer of subcutaneous fat; innate ability to swim; a 'diving-reflex' which slows down the heart-rate and reduces oxygen consumption when the face is submerged; face to face copulation; the ability to weep (with the exception of elephants, which by the way have webbing between their toes, and have been known to swim 300 miles); and far more sweat glands than any other land mammal [7].
In our books "The Driving Force: Food in Evolution and the Future": and "Nutrition & Evolution" (Crawford & Marsh) we added specifically environmental and nutritional dimensions to the debate, describing important implications for our food choices today [2].
New evidence is now coming from archeological discoveries in north and south Africa, Australia, Chile and northern Spain of remains and artifacts from 100,000 thousand years (kyr) ago in S.Africa [9], from 125 kyr ago in Eritrea, 14,700 years ago in Chile which clearly demonstrate that the early forebears of homo sapiens were shore-dwellers living on fish, shell fish, and aquatic plants, in addition to food from land or woods [10].
A significant number of top scientists from various discplines are now espousing the waters-edge evolution theory which explains that homo sapiens didn't come from the lines of prairie dwellers after all. Homo erectus, being shore dwelling, would have had a very different diet to that of the landlocked savannah-dwellers, with their 'meat and 2 roots and shoots' and neanderthal behaviour [3: 5: 10: 11].
100 kyr ago in the last ice-age, the sea level would have been much lower as water was held frozen in the poles. Using coastways as tracks, the early travellers radiated out from Africa using the oceans rivers and lakes for their food supply [9]. They would have had ample DHA (long chain essential fatty acid see below), one of two essential fatty acids which make up 60% of the human brain.
This "Out of Africa" hypothesis, pioneered by Chris Stringer, professor of Human Origins, from London's Natural History Museum refutes the "multi-regional development theory" which theorises that modern man emerged in different parts of the world at around the same time [9].
Meanwhile 'Mungo Man', from Lake Mungo Australia is, at 60,000 years old, challenging the Out of Africa enthusiasts. As our distinguished ancestors were travelling out of Africa over 100,000 years ago, developments of this tale will be fascinating. (As Mungo Man was lacustrine it does not detract from our thesis) [12].
A new/current paradigm shift
Thomas Kuhn in 1962 published his hugely successful book 'the Structure of Scientific Revolutions' - which was quoted for decades afterwards - describing how one scientific belief system - or paradigm - would, following progress in scientific knowledge, supecede previous paradigms which can be seen as the belief systems of previous eras [13].
Examples of paradigm shifts in the past include Darwin's theory of natural selection replacing the belief that God made the world in 7 days: and in Mendels discovery of recessant and dominant genes, resulting in what is known as 'the modern synthesis' in 1935 [2].
Paradigm shifts don't happen everyday and usually take decades to bite and take hold. Not everyone lives to see a paradigm change. So we are privileged at the moment to be witnessing a major paradigm shift in evolutionary thinking, by a growing number of senior scientists and researchers worldwide.
This new research which has followed on from the human genome project and subsequent DNA mapping, together with new work tracing isotope patterns which can show past climates, and exciting new paleontological finds worldwide point to a new environmental dimension being grafted into natural selection.
The new discoveries indicate that homo erectus, far from being a savannah dweller was a shore-line dweller, living at the waters-edge, on river and lake banks, and marine shores. From the above new work most paleonotologists have left the savannah origin of our ancestors behind, and are now espousing the new paradigm. It is now thought that our earliest ancestors, for perhaps hundreds of thousands of years, were shore dwelling, living off aquatic foods on the water side and land foods on the other.
The shore-dwelling foodchain would therefore be quite different to the meat and two veg of the savannah dwellers. Mineral and EFA content would have been far more opulent at the waters-edge. But the one nutrient which stands out is DHA. In its ready made form it is not available to the plains and savannah dwellers, apart from those who lived in well-rivered lands, islands or near coastal areas which would have provided bountiful supplies of fish, like Britain, Japan and much of the USA.
Top scientists worldwide are now pinpointing DHA's implications in more ways than brain size. DHA has been found to be used in the some of the most sophisticated bio-electrical wizzardry in the brain and nervous system: it acts both as biological building blocks, and because of the unique pattern of its carbon 'flexi-' chains and bendy 'double bonds', the DHA molecule appears particularly efficient at conducting bio-(di)-electrical messages along its structure. This efficacy seems unmatched by other essential fatty acids [3: 11].
It seems many people are at risk of DHA deficiency; not that (some) fish is not still plentiful: people are eating less (over half the world's fish catch goes to feed animals, and fish). Also overmuch meat eating (6 omega) can impede 3 omega levels as they both compete for the same enzyme [22].
Pondering on the now well-understood transgenerational effects of nutrition [11: 14], and considering the eating habits of certain social groupings over the last couple of centuries, it could be reasoned that the diseases of our civilisation - some of which have reached pandemic proportions, such as cancer, heart disease, depression, mental illness, asthma, alzheimers, diabetes, suicide and other common problems such as low birth-weight babies, autistic, attention deficit hyperactive and allergic children (ADHD), can be seen, collectively, as examples of non-adaptive evolution [15].
This non-adaptation is 'a response to', or 'the results of' an increasingly unsupportive, nutrient depleted and polluted environment - providing poor national diets on a multi-generational level. Many of the above diseases are implicated with EFA deficiency, usually accompanied by multiple vitamin, mineral and fibre shortfalls.
Front-line researchers worldwide are now suggesting that DHA deficiency in pregnancy is giving rise to babies with a similar deficiencies, which affect both the developing and developed brain. Mood disorder, depression and possibily schizophrenia are implicated: as is the inclination in sufferers to violence [16]. ADHD is definitively linked to DHA deficiency in the minds of most front line researchers [22].
Many of us would support the ideas of the (then) First Lady Hilary Clinton (speech 20. 3. 200) when she implored everyone, including the professions, to come up with more help for children with behavioural and mental disorders. Commenting on a 4 year period ('91 - '95) when the use of ritalin alone rose by 150%, and anti-depressants by over 200%, she called on 'experts from the administration, parents, advocates, educators, researchers, health-care professionals and consumers' to confer and come up with some answers [19, 20, 21].
Coincidentally or not, Great Britain with its Neanderthal diet, has the worst health record of any country in western Europe. We also are known for anti-social behaviour; and have more people in prison than any West European country apart from Portugal.
This scenario of 'worst diet - most anti-social behaviour' has a kind of logical, common-sense ring to it, which might even motivate politicians and professors such as run our Food Standards Agency to brush up on nutrition [15: 17]. How can food be safe - in the long term - if it is grown on nutrient and humus starved soil, sprayed with potentially harmful chemicals up to ten times, refined and purified almost to nutritional extinction, filled with more 'edible' chemicals, and often manufactured months if not years before?
Making political targets to ease these problems is worthy: more teams to discover the cancers, and providing better ways of coping with them sound very good. But how about preventing it in the first place?
We know that many cancers grow in specific nutrient-starved conditions [18]. Heart disease is largely preventable: yet the scientific knowledge is often going little further than researchers and pioneers and a few hundred medical doctors? [11].
One suspects this is for political and economic reasons, with the Health of the Nation being skilfully played-off against the Health of Share-Performance. The latter seem currently to be in a stronger situation.
Solutions lie in educating the public (including the professions), improving the quality of our environment, our soils, our foodchain and eating habits, thereby helping to prevent greater disaster in the near future.
Homo erectus, our earliest line-ancestors, living as forest / water shore dwellers would have obtained a much broader spectrum of nutrients, including DHA and minerals, and had the intelligence during those harsh times to travel on and around the southern shores, following the seafood supplies around the coasts, delving ever deeper into both hemispheres.
For the last number of generations the northern hemisphere diet of meat from large mammals and two veg has been mimicking the eating habits of the extinct Neanderthals: whose diet comprised of meat from large mammals with seeds, roots and leaves. This is a diet inviting deficiences of DHA and minerals and a surfeit of 'non-communicable diseases' (degenerative disease)... which are in fact communicable - from one generation to the next.
Remembering nutrition's transgenerational effects, we should all make an effort to reverse the progress of the degenerative diseases (eating 2 - 3 portions of oil fish a week: herring, mackerel, sardines, sild, sprats, salmon, oysters, other shell fish, algae, seaweed, etc).
In so doing we could individually play our own small part in reducing the load on our strained national health service, and reverse the trend - seen in increasingly anti-social behaviour (particularly at football 'games') and possible steps towards atavism.
Violence, once widely attributed to the 'aggressive' ingredient of red meat, as we have already seen, is now thought to be caused by poor brain development through deficiences of DHA [14]. Similarly DHA deficiencies in a developed human brain can be linked with violent behaviour. This as we have seen above can be exarcerbated by heavy meat eating at the exclusion of fish, with the meat ( 6 omega) preventing the uptake of DHA.
To conclude: for more than 70 years paleobiologists held the view that it was on the savannahs, in fierce laboratories of competition, that the human brain evolved. Michael Crawford (above) comments "The biochemical evidence indicates that this was impossible. The savannah species lost brain capacity logarithmically as they evolved larger bodies. The richest source of the lipids and trace elements that would have been needed for cerebral expansion was at the land / water interface" [11].
Be prepared for more discoveries in the fields of EFA's and genetic expression. If nutritional biochemicals can instruct the genetic mechanism, our current evolutionary theory will have to expand its borders: this 'enlargement' will be music to the ears of environmentalists.
POSTSCRIPT
"It is generally acknowledged that all organic beings have been formed on two great laws - 'Unity of Type' and 'the Conditions of Existence'... in fact, the law of the Conditions of Existence is the higher law, as it includes, through the inheritance of former variations and adaptations, that of Unity of Type'[1].
"Changed conditions of life are of the highest importance in causing variability, both by acting directly on the organisation, and indirectly by affecting the reproductive mechanism" [1].
David Marsh 17/1/2001
REFERENCES