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http://www.guardian.co.uk/crime/article ... 91,00.html

Omega-3, junk food and the link between violence and what we eat

Research with British and US offenders suggests nutritional deficiencies may play a key role in aggressive bevaviour

Felicity Lawrence
Tuesday October 17, 2006
The Guardian

That Dwight Demar is able to sit in front of us, sober, calm, and employed, is "a miracle", he declares in the cadences of a prayer-meeting sinner. He has been rocking his 6ft 2in bulk to and fro while delivering a confessional account of his past into the middle distance. He wants us to know what has saved him after 20 years on the streets: "My dome is working. They gave me some kind of pill and I changed. Me, myself and I, I changed."

Demar has been in and out of prison so many times he has lost count of his convictions. "Being drunk, being disorderly, trespass, assault and battery; you name it, I did it. How many times I been in jail? I don't know, I was locked up so much it was my second home."

Demar has been taking part in a clinical trial at the US government's National Institutes for Health, near Washington. The study is investigating the effects of omega-3 fatty acid supplements on the brain, and the pills that have effected Demar's "miracle" are doses of fish oil.

The results emerging from this study are at the cutting edge of the debate on crime and punishment. In Britain we lock up more people than ever before. Nearly 80,000 people are now in our prisons, which reached their capacity this week.

But the new research calls into question the very basis of criminal justice and the notion of culpability. It suggests that individuals may not always be responsible for their aggression. Taken together with a study in a high-security prison for young offenders in the UK, it shows that violent behaviour may be attributable at least in part to nutritional deficiencies.

The UK prison trial at Aylesbury jail showed that when young men there were fed multivitamins, minerals and essential fatty acids, the number of violent offences they committed in the prison fell by 37%. Although no one is suggesting that poor diet alone can account for complex social problems, the former chief inspector of prisons Lord Ramsbotham says that he is now "absolutely convinced that there is a direct link between diet and antisocial behaviour, both that bad diet causes bad behaviour and that good diet prevents it."

The Dutch government is currently conducting a large trial to see if nutritional supplements have the same effect on its prison population. And this week, new claims were made that fish oil had improved behaviour and reduced aggression among children with some of the most severe behavioural difficulties in the UK.

Deficiency

For the clinician in charge of the US study, Joseph Hibbeln, the results of his trial are not a miracle, but simply what you might predict if you understand the biochemistry of the brain and the biophysics of the brain cell membrane. His hypothesis is that modern industrialised diets may be changing the very architecture and functioning of the brain.

We are suffering, he believes, from widespread diseases of deficiency. Just as vitamin C deficiency causes scurvy, deficiency in the essential fats the brain needs and the nutrients needed to metabolise those fats is causing of a host of mental problems from depression to aggression. Not all experts agree, but if he is right, the consequences are as serious as they could be. The pandemic of violence in western societies may be related to what we eat or fail to eat. Junk food may not only be making us sick, but mad and bad too.

In Demar's case the aggression has blighted many lives. He has attacked his wife. "Once she put my TV out the door, I snapped off and smacked her." His last spell in prison was for a particularly violent assault. "I tried to kill a person. Then I knew something need be done because I was half a hundred and I was either going to kill somebody or get killed."

Demar's brain has blanked out much of that last attack. He can remember that a man propositioned him for sex, but the details of his own response are hazy.

When he came out of jail after that, he bought a can of beer and seemed headed for more of the same until a case worker who had seen adverts for Hibbeln's trial persuaded him to take part.

The researchers at the National Institute on Alcohol Abuse and Alcoholism, which is part of NIH, had placed adverts for aggressive alcoholics in the Washington Post in 2001. Some 80 volunteers came forward and have since been enrolled in the double blind study. They have ranged from homeless people to a teacher to a former secret service agent. Following a period of three weeks' detoxification on a locked ward, half were randomly assigned to 2 grams per day of the omega-3 fatty acids EPA and DHA for three months, and half to placebos of fish-flavoured corn oil.

An earlier pilot study on 30 patients with violent records found that those given omega-3 supplements had their anger reduced by one-third, measured by standard scales of hostility and irritability, regardless of whether they were relapsing and drinking again. The bigger trial is nearly complete now and Dell Wright, the nurse administering the pills, has seen startling changes in those on the fish oil rather than the placebo. "When Demar came in there was always an undercurrent of aggression in his behaviour. Once he was on the supplements he took on the ability not to be impulsive. He kept saying, 'This is not like me'."

Demar has been out of trouble and sober for a year now. He has a girlfriend, his own door key, and was made employee of the month at his company recently. Others on the trial also have long histories of violence but with omega-3 fatty acids have been able for the first time to control their anger and aggression. J, for example, arrived drinking a gallon of rum a day and had 28 scars on his hand from punching other people. Now he is calm and his cravings have gone. W was a 19st barrel of a man with convictions for assault and battery. He improved dramatically on the fish oil and later told doctors that for the first time since the age of five he had managed to go three months without punching anyone in the head.

Threat to society

Hibbeln is a psychiatrist and physician, but as an employee of the US government at the NIH he wears the uniform of a commander, with his decorations for service pinned to his chest. As we queued to get past the post-9/11 security checks at the NIH federal base, he explained something of his view of the new threat to society.

Over the last century most western countries have undergone a dramatic shift in the composition of their diets in which the omega-3 fatty acids that are essential to the brain have been flooded out by competing omega-6 fatty acids, mainly from industrial oils such as soya, corn, and sunflower. In the US, for example, soya oil accounted for only 0.02% of all calories available in 1909, but by 2000 it accounted for 20%. Americans have gone from eating a fraction of an ounce of soya oil a year to downing 25lbs (11.3kg) per person per year in that period. In the UK, omega-6 fats from oils such as soya, corn, and sunflower accounted for 1% of energy supply in the early 1960s, but by 2000 they were nearly 5%. These omega-6 fatty acids come mainly from industrial frying for takeaways, ready meals and snack foods such as crisps, chips, biscuits, ice-creams and from margarine. Alcohol, meanwhile, depletes omega-3s from the brain.

To test the hypothesis, Hibbeln and his colleagues have mapped the growth in consumption of omega-6 fatty acids from seed oils in 38 countries since the 1960s against the rise in murder rates over the same period. In all cases there is an unnerving match. As omega-6 goes up, so do homicides in a linear progression. Industrial societies where omega-3 consumption has remained high and omega-6 low because people eat fish, such as Japan, have low rates of murder and depression.

Of course, all these graphs prove is that there is a striking correlation between violence and omega 6-fatty acids in the diet. They don't prove that high omega-6 and low omega-3 fat consumption actually causes violence. Moreover, many other things have changed in the last century and been blamed for rising violence - exposure to violence in the media, the breakdown of the family unit and increased consumption of sugar, to take a few examples. But some of the trends you might expect to be linked to increased violence - such as availability of firearms and alcohol, or urbanisation - do not in fact reliably predict a rise in murder across countries, according to Hibbeln.

There has been a backlash recently against the hype surrounding omega-3 in the UK from scientists arguing that the evidence remains sketchy. Part of the backlash stems from the eagerness of some supplement companies to suggest that fish oils work might wonders even on children who have no behavioural problems.

Alan Johnson, the education secretary, appeared to be jumping on the bandwagon recently when he floated the idea of giving fish oils to all school children. The idea was quickly knocked down when the food standards agency published a review of the evidence on the effect of nutrition on learning among schoolchildren and concluded there was not enough to conclude much, partly because very few scientific trials have been done.

Professor John Stein, of the department of physiology at Oxford University, where much of the UK research on omega-3 fatty acid deficiencies has been based, agrees: "There is only slender evidence that children with no particular problem would benefit from fish oil. And I would always say [for the general population] it's better to get omega-3 fatty acids by eating fish, which carries all the vitamins and minerals needed to metabolise them."

However, he believes that the evidence from the UK prison study and from Hibbeln's research in the US on the link between nutritional deficiency and crime is " strong", although the mechanisms involved are still not fully understood.

Hibbeln, Stein and others have been investigating what the mechanisms of a causal relationship between diet and aggression might be. This is where the biochemistry and biophysics comes in.

Essential fatty acids are called essential because humans cannot make them but must obtain them from the diet. The brain is a fatty organ - it's 60% fat by dry weight, and the essential fatty acids are what make part of its structure, making up 20% of the nerve cells' membranes. The synapses, or junctions where nerve cells connect with other nerve cells, contain even higher concentrations of essential fatty acids - being made of about 60% of the omega-3 fatty acid DHA.

Communication between the nerve cells depends on neurotransmitters, such as serotonin and dopamine, docking with receptors in the nerve cell membrane.

Omega-3 DHA is very long and highly flexible. When it is incorporated into the nerve cell membrane it helps make the membrane itself elastic and fluid so that signals pass through it efficiently. But if the wrong fatty acids are incorporated into the membrane, the neurotransmitters can't dock properly. We know from many other studies what happens when the neurotransmitter systems don't work efficiently. Low serotonin levels are known to predict an increased risk of suicide, depression and violent and impulsive behaviour. And dopamine is what controls the reward processes in the brain.

Laboratory tests at NIH have shown that the composition of tissue and in particular of the nerve cell membrane of people in the US is different from that of the Japanese, who eat a diet rich in omega-3 fatty acids from fish. Americans have cell membranes higher in the less flexible omega-6 fatty acids, which appear to have displaced the elastic omega-3 fatty acids found in Japanese nerve cells.

Hibbeln's theory is that because the omega-6 fatty acids compete with the omega-3 fatty acids for the same metabolic pathways, when omega-6 dominates in the diet, we can't convert the omega-3s to DHA and EPA, the longer chain versions we need for the brain. What seems to happen then is that the brain picks up a more rigid omega-6 fatty acid DPA instead of DHA to build the cell membranes - and they don't function so well.

Other experts blame the trans fats produced by partial hydrogenation of industrial oils for processed foods. Trans fats have been shown to interfere with the synthesis of essentials fats in foetuses and infants. Minerals such as zinc and the B vitamins are needed to metabolise essential fats, so deficiencies in these may be playing an important part too.

There is also evidence that deficiencies in DHA/EPA at times when the brain is developing rapidly - in the womb, in the first 5 years of life and at puberty - can affect its architecture permanently. Animal studies have shown that those deprived of omega-3 fatty acids over two generations have offspring who cannot release dopamine and serotonin so effectively.

"The extension of all this is that if children are left with low dopamine as a result of early deficits in their own or their mother's diets, they cannot experience reward in the same way and they cannot learn from reward and punishment. If their serotonin levels are low, they cannot inhibit their impulses or regulate their emotional responses," Hibbeln points out.

Mental health

Here too you have one possible factor in cycles of deprivation (again, no one is suggesting diet is the only factor) and why criminal behaviour is apparently higher among lower socio-economic groups where nutrition is likely to be poorer.

These effects of the industrialisation of the diet on the brain were also predicted in the 1970s by a leading fats expert in the UK, Professor Michael Crawford, now at London's Metropolitan University. He established that DHA was structural to the brain and foresaw that deficiencies would lead to a surge in mental health and behavioural problems - a prediction borne out by the UK's mental health figures.

It was two decades later before the first study of the effect of diet on behaviour took place in a UK prison. Bernard Gesch, now a senior researcher at Stein's Oxford laboratory, first became involved with nutrition and its relationship to crime as a director of the charity Natural Justice in northwest England. He was supervising persistent offenders in the community and was struck by their diets. He later set out to test the idea that poor diet might cause antisocial behaviour and crime in the maximum security Aylesbury prison.

His study, a placebo-controlled double blind randomised trial, took 231 volunteer prisoners and assigned half to a regime of multivitamin, mineral and essential fatty acid supplements and half to placebos. The supplement aimed to bring the prisoners' intakes of nutrients up to the level recommended by government. It was not specifically a fatty acid trial, and Gesch points out that nutrition is not pharmacology but involves complex interactions of many nutrients.

Prison trial

Aylesbury was at the time a prison for young male offenders, aged 17 to 21, convicted of the most serious crimes. Trevor Hussey was then deputy governor and remembers it being a tough environment. "It was a turbulent young population. They had problems with their anger. They were all crammed into a small place and even though it was well run you got a higher than normal number of assaults on staff and other prisoners."

Although the governor was keen on looking at the relationship between diet and crime, Hussey remembers being sceptical himself at the beginning of the study. The catering manager was good, and even though prisoners on the whole preferred white bread, meat and confectionery to their fruit and veg, the staff tried to encourage prisoners to eat healthily, so he didn't expect to see much of a result.

But quite quickly staff noticed a significant drop in the number of reported incidents of bad behaviour. "We'd just introduced a policy of 'earned privileges' so we thought it must be that rather than a few vitamins, but we used to joke 'maybe it's Bernard's pills'."

But when the trial finished it became clear that the drop in incidents of bad behaviour applied only to those on the supplements and not to those on the placebo.

The results, published in 2002, showed that those receiving the extra nutrients committed 37% fewer serious offences involving violence, and 26% fewer offences overall. Those on the placebos showed no change in their behaviour. Once the trial had finished the number of offences went up by the same amount. The office the researchers had used to administer nutrients was restored to a restraint room after they had left.

"The supplements improved the functioning of those prisoners. It was clearly something significant that can't be explained away. I was disappointed the results were not latched on to. We put a lot of effort into improving prisoners' chances of not coming back in, and you measure success in small doses."

Gesch believes we should be rethinking the whole notion of culpability. The overall rate of violent crime in the UK has risen since the 1950s, with huge rises since the 1970s. "Such large changes are hard to explain in terms of genetics or simply changes of reporting or recording crime. One plausible candidate to explain some of the rapid rise in crime could be changes in the brain's environment. What would the future have held for those 231 young men if they had grown up with better nourishment?" Gesch says.

He said he was currently unable to comment on any plans for future research in prisons, but studies with young offenders in the community are being planned.

For Hibbeln, the changes in our diet in the past century are "a very large uncontrolled experiment that may have contributed to the societal burden of aggression, depression and cardiovascular death". To ask whether we have enough evidence to change diets is to put the question the wrong way round. Whoever said it was safe to change them so radically in the first place?

Young offender's diet

One young offender had been sentenced by the British courts on 13 occasions for stealing trucks in the early hours of the morning.

Bernard Gesch recorded the boy's daily diet as follows:

Breakfast: nothing (asleep)

Mid morning: nothing (asleep)

Lunchtime: 4 or 5 cups of coffee with milk and 2½ heaped teaspoons of sugar

Mid afternoon: 3 or 4 cups of coffee with milk and 2½ heaped sugars

Tea: chips, egg, ketchup, 2 slices of white bread, 5 cups of tea or coffee with milk and sugar

Evening: 5 cups of tea or coffee with milk and sugar, 20 cigarettes, £2 worth of sweets, cakes and if money available 3 or 4 pints of beer.


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Я вот не смогу соблюдать диету, когда голодная становлюсь раздражительной... :wink:



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Wholly possible,but matter of fact that,these studies concerns with only USA.Try to teach hen to dance-as always...&....as always....... Итд итп и по кругу.По моему они всегда только и делают,что занимаются подобной ерундой.Это ,как говорится -Наш Кузенька с жиру бесится,а как побесится,так и спать пойдёт.Сюда бы этих исследователей-Жирное не кальцированное....В нашей стране это по моему вообще не приемлемо,и обсуждать будет довольно сложно.Тут многим и без диет пожрать нечего.



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http://www.naddum.com/Articles/food_die ... _print.htm

Not Enough Fish in the Sea

By George Monbiot, AlterNet
Posted on June 30, 2006, Printed on June 30, 2006

http://www.alternet.org/story/37862/

The more it is tested, the more compelling the hypothesis becomes. Dyslexia, ADHD, dyspraxia and other neurological problems seem to be associated with a deficiency of omega-3 fatty acids, especially in the womb. The evidence of a link with depression, chronic fatigue syndrome and dementia is less clear, but still suggestive. None of these conditions are caused exclusively by a lack of these chemicals, or can be entirely remedied by their application, but it's becoming pretty obvious that some of our most persistent modern diseases are, at least in part, diseases of deficiency.

Last year, for example, researchers at Oxford published a study of 117 children suffering from dyspraxia. Dyspraxia causes learning difficulties, disruptive behaviour and social problems. It affects about 5 percent of children. Some of the children were given supplements of omega-3 and -6 fatty acids, others were given placebos. The results were extraordinary. In three months, the reading age of the experimental group rose by an average of 9.5 months, while the control group's rose by 3.3. Other studies have shown major improvements in attention, behavior and IQ.

This shouldn't surprise us. During the Paleolithic period, human beings ate roughly the same amount of omega-3 fatty acids as omega-6s. Today we eat 17 times as much omega-6 as omega-3. Omega-6s are found in vegetable oils, while most of the omega-3s we eat come from fish. John Stein, a professor of physiology at Oxford who specializes in dyslexia, believes that fish oils permitted humans to make their great cognitive leap forwards. The concentration of omega-3s in the brain, he says, could provide more evidence that human beings were, for a while, semi aquatic.

Stein believes that when the cells which are partly responsible for visual perception -- the magnocellular neurones -- are deficient in omega-3s, they don't form as many connections with other cells and don't pass on information as efficiently. Their impaired development explains, for example, why many dyslexic children find that letters appear to jump around on the page.

So at first sight the government's investigation into the idea of giving fish oil capsules to schoolchildren seems sensible. The food standards agency is conducting a review of the effects of omega-3s on childrens' behavior and performance in school. Alan Johnson, Britain's secretary of state for education, is taking an interest. Given the accumulating weight of evidence, it would be surprising if he does not decide to go ahead. Already, companies such as St. Ivel and Marks and Spencer are selling foods laced with omega-3s.

There is only one problem: There are not enough fish. In March an article in the British Medical Journal observed that "we are faced with a paradox. Health recommendations advise increased consumption of oily fish and fish oils within limits, on the grounds that intake is generally low. However Š we probably do not have a sustainable supply of long chain omega-3 fats."

Our brain food is disappearing

If you want to know why, read Charles Clover's beautifully written book, The End of the Line. Clover traveled all over the world, showing how the grotesque mismanagement of fish stocks has spread like an infectious disease. Governments help their fishermen to wipe out local shoals, then pay them to build bigger and more powerful boats so they can go further afield. When they have cleaned up their own continental shelves, they are paid by taxpayers to destroy other people's stocks.

The European Union, for example, has bought our pampered fishermen the right to steal protein from the malnourished people of Senegal and Angola. West African stocks are now going the same way as North Sea cod and Mediterranean tuna.

I first realized just how mad our fishing policies have become when playing a game of ultimate frisbee in my local park. Taking a long dive, I landed with my nose in the grass. It smelt of fish. To the astonishment of passersby, I crawled across the lawns, sniffing them. The whole park had been fertilized with fishmeal. Fish are used to feed cattle, pigs, poultry and other fish -- in the farms now proliferating all over the world. Those rearing salmon, cod and tuna, for example, produce about half as much fish as they consume.

Until 1996, when public outrage brought the practice to a halt, a power station in Denmark was running on fish oil. Now I have discovered that the U.S. Department of Energy is subsidizing the conversion of fish oil into biodiesel through its "regional biomass energy program." It hopes that fish will be used to provide electricity and heating to homes in Alaska. It describes them as "a sustainable energy supply."

Three years after Ransom Myers and Boris Worm published their seminal study in Nature, showing that global stocks of predatory fish have declined by 90 percent, nothing has changed. The fish stall in my local market still sells steaks from the ocean's charismatic megafauna: swordfish, sharks and tuna, despite the fact that their conservation status is now, in many cases, similar to that of the Siberian tiger. Even my own newspaper's weekend magazine publishes recipes for endangered species.

The European Fisheries Council has just reversed the only sensible policy it has ever introduced. Having dropped them in 2002, it has decided to reinstate subsidies for new boat engines. Once again we will be paying billions to support overfishing. Franco rose to power with the help of the whalers and industrial fishermen of his native Galicia. Somehow the old fascists in Vigo -- the center of the European industry's power -- still seem to exercise an extraordinary degree of control.

If fish stocks were allowed to recover and fishing policies reflected scientific advice, there might just about be enough to go round. To introduce mass medication with fish oil under current circumstances could be a recipe for the complete collapse of global stocks. Yet somehow we have to prevent many thousands of lives from being ruined by what appears to be a growing problem of malnutrition.

Some plants -- such as flax and hemp -- contain omega-3 oils, but not of the long-chain varieties our cell membranes need. Only some people can convert them, and even then slowly and inefficiently. But a few weeks ago, a Swiss company called eau+ published a press release claiming that it has been farming "a secret strain of algae called V-Pure" which produces the right kind of fatty acids. It says it's on the verge of commercializing a supplement.

As the claims and the terrible names put me in mind of the slushiest kind of New Age therapy, I was, at first, suspicious. So I went to see professor Stein to ask him whether it was likely to be true. He could be said to have a countervailing interest: His brother is the celebrity fish chef Rick Stein. But he happened to have met the company's founder the day before, and he was impressed. The oils produced by some species of algae, he told me, are chemically identical to those found in fish: In fact this is where the fish get them. "I think they're fairly optimistic about the timescale. But there is no theoretical impediment. I haven't yet seen his evidence, but I formed a very strong impression that he is an honest man."

He had better be, and his project had better work. Otherwise the human race is destined to take a great cognitive leap backwards.

George Monbiot is the author of "Poisoned Arrows" and "No Man's Land" (Green Books). Read more of his writings at Monbiot.com.

This article originally appeared in the Guardian.
© 2006 Independent Media Institute. All rights reserved.
View this story online at: http://www.alternet.org/story/37862/


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Да, да насчет хемпа он все правельно подметил. Только именно из хемпа усваивается хорошо.



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Не знаю как насчёт хемпа, но вообще-то источником усваиваемых омега-3 жирных кислот является рыба и морепродукты.

Причём, рыба неспособна синтезировать омега-3 жирные кислоты точно так же, как и человек. Омега-3 жирные кислоты накапливаются в пищевой цепочке.
Те омега-3 жирные кислоты, которые содержаться в рыбе и морепродуктах, синтезируются водорослями, а затем постепенно накапливаются в пищевой цепочке, причём, на каждой стадии пищевой цепочки их концентрация возрастает.
Потому больше всего омега-3 жирных кислот содержат крупные хищные виды рыб, вроде лосося и макрели, которые занимают одни из самых верхних этажей пищевой пирамиды.


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http://newsletter.vitalchoice.com/e_art ... K,b1pTrCB7

Omega-3 Brain Evolution Theory Gets a Boost

Findings from coastal Africa support the idea that fishy diets helped humans evolve big brains rapidly

by Craig Weatherby

Our earliest human-like ancestors evolved brains bigger than their primate cousins’.

Was it because they gravitated to watery shores, abundant in plants and animals high in DHA, the long-chain “marine” omega-3 that dominates human brains?

When we attended the 2005 Seafood & Health conference in Washington DC, we were greatly impressed with a keynote speech by Professor Michael Crawford, Ph.D. director of the Institute of Brain Chemistry and Human Nutrition at North London University.

His basic thesis, shared by some other researchers, is that the explosion in hominid brain size that led to Homo sapiens depended on a supply of DHA-rich aquatic food. He made many compelling points, including that East Africa's Olduvai Gorge, site of our most famous early ancestors, was, at the time, Olduvai River.

However, Dr. Crawford's hypothesis has many critics, who note that modern humans thrive on diets rather low in DHA, and that many pre-human and early human species roamed areas not known for abundant aquatic life. In addition, there is no evidence a diet high in DHA alone results bigger brains, as attested by the tiny brains of fish and seabirds.

Critics of the water-foods hypothesis of brain evolution also point to the proven association between proportionally bigger brains and diverse, high-fat, and high-protein diets in general.

While neither side in this debate is likely to be proven completely right or wrong, new evidence seems to tip the scales toward Dr. Crawford’s camp.

Earliest-ever seashore settlements found on South African coast

Most researchers believe that modern humans first emerged between 150,000 and 200,000 years ago, in eastern Africa.

However, it is not clear exactly when early humans developed the capacity for symbolic thought, such as language and symbolic or representative art.

The debate between advocates of Dr. Crawford’s “aquatic brain” hypothesis and the skeptical majority of paleoanthropologists may rest on the answer to a key question.

Did modern cognitive abilities occurred gradually, purely in response to natural selection, or quite suddenly, after a boost in brain size and/or neurological capacity that was fueled by hominid diets newly rich in aquatic foods?

The prestigious journal Nature just published findings from a team led by paleoanthropologist Curtis Marean of Arizona State University … discoveries that seem to support the possibility of a diet-driven burst in brain size or power (ASU 2007).

Mareans’ team found evidence of early humans living on the coast in South Africa 164,000 years ago: a date far earlier than any ever documented for shore-dwelling humans, and smack in the center of the time period when anatomically modern humans emerged.

(By “anatomically modern”, paleoanthropologists mean homo-genus primates highly similar to 21st century Homo sapiens in terms of body proportions, teeth, jaws, skull shape, brain-cavity size, and other major features.)

As Dr. Marean said in a press release, “Our findings show that at 164,000 years ago in coastal South Africa humans expanded their diet to include shellfish and other marine resources, perhaps as a response to harsh environmental conditions. This is the earliest dated observation of this behavior.” (ASU 2007)

Critically, Marean’s team discovered evidence that these people were using pigment, probably to make symbols or art, and were using “bladelet” stone tool technology, whose oldest previously documented occurrence had been about 70,000 years ago.

The ASU release makes a very pertinent point: “These new findings not only move back the timeline for the evolution of modern humans, they show that lifestyles focused on coastal habitats and resources may have been crucial to the evolution and survival of these early humans.” (ASU 2007)

These intriguing findings will not end the debate over brain evolution, but they will certainly keep it nourished.

And other recent research lends support – albeit less direct – to the “aquatic brain” hypothesis of evolution

Pre-human savanna dwellers show evidence of shellfish diets

Two years ago, it was reported that instead of the exclusively plant-based diet that savanna-dwelling pre-humans were thought to eat, they might have been omnivores who ate fresh-water snails and crustaceans.

The earliest members of our genus, Homo, shared the African plains with another group of hominids, the australopithecines, for the first two million years of their existence. The two groups were closely related, but the australopithecines had giant molars, thick tooth enamel and a bony skull crest that anchored huge chewing muscles.

Paleoanthropologists presumed, logically enough, that the australopithecines used their heavy duty head and jaw structures to chew tough plant foods. But the results of a 2005 study suggested otherwise.

Homo developed a large brain and tool-making capabilities that enabled it to pursue a diet rich in meat, and researchers have presumed that the australopithecines evolved rugged anatomical equipment to grind up tough plant fare.

But recent findings from studies of carbon isotopes in ancestral African fossils show that the ratio of carbon 13 to carbon 12 in the teeth of australopithecines is higher than the ratio seen in animals that eat mostly fruit and nuts, but lower than in animals that subsist on grass seeds (Wong K 2006).

Alan B. Shabel of the University of California, Berkeley, has hypothesized that australopithecines’ teeth and jaws were built for eating hard-shelled invertebrates like snails and shellfish.

Even though eastern and southern Africa – where virtually all of the continent's hominid and australopithecine fossils are found – was in a dry period when the two pre-human species co-existed, wetlands dotted these savannas and plains than as they do now.

Much like modern wetlands, these ancient lakes, rivers and marshes were rich in shoreline creatures such as giant land snails and crabs.

And when Shabel examined modem African otters and the marsh mongooses, which specialize in eating these very same snails and crabs, he found the same distinctive skull features seen in the australopithecines.

Shabel then analyzed carbon isotopes in the otters and mongoose and their snail and crab prey. Indeed, the carbon profiles of all of these animals’ were similar to those of the ancient pre-human australopithecines (Wong K 2006).

This does not provide direct evidence for the idea that modern human brains were made possible by eating aquatic foods.

But it does suggest that savanna-dwelling pre-humans had access to aquatic foods, and ate significant amounts of them.

Our more direct Homo-genus ancestors did not evolve big jaws to chew shells. Instead, their brains are believed to have been bigger than the australopithecines’, so Homo species may have smashed aquatic animals’ shells or used tools to dig out the meat.

Thus, absent big teeth and jaws our Homo predecessors could still make protein- and omega-3-rich snails and crabs part of their omnivorous diet, thereby enabling faster brain evolution.

And the new findings out of South Africa suggest that availability of a far greater abundance of omega-3s, from ocean animals and plants, may have fueled a rapid leap forward in human brain size and power.

We’ll keep you posted on this intriguing, still-unfolding area of evolutionary inquiry.

Sources

* Arizona State University (ASU). ASU team detects earliest modern humans. Accessed online October 20, 2007 at http://asunews.asu.edu/20071016_earlyhumans
* Wong K. Food for Thought: Giant Hominid teeth not for crunching nuts, but shellfish. Scientific American, February 13, 2006. Accessed online October 20, 2007 at http://www.sciam.com/article.cfm?articl ... sc=I100322
* Minkel JR. Earliest Known Seafood Dinner Discovered: Dished out with a side of symbolic thought. Scientific American, October 17, 2007. Accessed online October 20, 2007 at http://www.sciam.com/article.cfm?articl ... anID=sa027


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