With the Advent of Agriculture, Human Bones Dramatically Weakened

By Carl Engelking | December 22, 2014 4:03 pm

leisure

Early human ancestors spent eons testing their skeletons while jogging through untamed landscapes hunting and gathering food to survive. Life is significantly easier today, and evidence of a more leisurely lifestyle is showing up in our rested bones.

Since the invention of agriculture, new research shows, human bones have grown lighter and far less dense than those of early humans and closely related primates. Researchers believe sedentary lifestyles — made possible by agriculture and technology — are the root cause of human bone degradation over the past 1,000 years. Their findings reinforce the idea that exercise, not diet, is key to preventing fractures and osteoporosis.

Thin Bones

Researchers in two different studies X-rayed samples of human bones from various points in the archaeological record, as well as bones from various modern primate species. In both studies, researchers were most interested in trabecular bone, which is the sponge-like internal structure of bones that gives them added strength.

Trabecular bone is of particular interest because it can change its shape and structure depending on the loads that are imposed on it. Basically, more load stress yields higher bone density and fewer air pockets in spongy trabecular bone. The more we exercise in life the stronger our bones grow, until they hit peak strength around the age of 30. After that, the aging process degrades our bones.

A New Development

Researchers found that early hunter-gatherers had far denser trabecular bone than modern humans, and that the decrease in bone density was more pronounced in lower limbs than in upper limbs, suggesting a link between bone density and changes in mobility. The density of 7,000-year-old hunter-gatherers’ bones was 20 percent higher than 700-year-old farmers’. Go back 150,000 years, and hominids’ bones were even denser.

What’s more, the evidence suggests the shift from thick-boned hunters to frail modern man happened relatively recently and rapidly in terms of evolutionary timelines. Researchers believe human bone density will continue to decline at an accelerated rate as technology continues to make life less laborious on our bodies. Researchers published their findings Monday in the journal Proceedings of the National Academies of Science (study one, study two).

Digging Through Bones

Although researchers found a link between lifestyles and bone density, there are still plenty of questions to answer. Trabecular bone architecture can vary in several ways including its shape, thickness and spacing. The current study didn’t account for all of these parameters, which could affect strength.

And if lack of activity means flimsier bones, researchers want to see if the obverse is true. The team plans to study the bones of modern super-marathon runners to see if they’re more closely similar to those of human ancestors.

 

Photo credit: Sebastian Kaulitzki/Shutterstock

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  • guest87

    Why you deleted my comment …?! Affraid about the facts??! :/

  • Mian Hanan53

    Yes

  • http://explaintwilightbreakingdawnending.blogspot.com/ catherinemostly

    I can certainly believe this… The less we need to do, the less we do (although we also ‘enjoy’ life in general more, I think). On top of getting ‘lazier’ – we also become interested in stupid, silly things that we would otherwise probably not be paying attention to, such as ‘reality’ shows, LoL!

    Lots of people believe that Humanity changed significantly as a result of the development of farming cultures vs. hunter/gatherer cultures. Some people also believe that aliens or some other mystical/spiritual force on the planet ‘helped’ Humans down this agricultural path with the intention of harming us, somehow.

    Perhaps that’s why a comment was deleted? 😉

    It really doesn’t matter HOW things came to us and/or changed the evolution of our societies. Dear God, we’re HERE as we are; and there isn’t much changing about that now, ha!

  • doramin

    This can’t be evolution. It has to be individual levels of activity. Humans can’t change in just a few thousand years.

    • Friz Martin

      I imagine if all the bone density measurements were done at birth or a reasonably short time afterwards we would have a better grasp of what our genes are initially programmed for. Then changes would cloud the picture as each individual adapted to their environment. Of course this would require a reference of historical bone density measurements of infants/young only, not an item in great supply.

      The general ability of modern “weak boned” human individuals to procreate and nuture their young with some semblance of normalcy would make any evolutionary genetic changes very slight.

    • Mel63

      Human evolution is sometimes quick, sometimes slow. According to recent studies it is getting faster. Activity level of the species is a driver of evolution. You are correct on that count. The dietary change from hunter to farmer would have accelerated the process, as well.

  • Michele Romeo

    There is tons of clinical evidence linking bone density and strength to regular exercise. When are we going to wake up and get unplugged? When we can no longer walk?

  • KEN

    I seriously doubt the “evidence” qualifies as truly random selection and therefor the results are merely reasonable conjecture supported by some “facts”. Without detailed data on nutrition, life style, prey, hunting techniques, farming crops, farming techniques, it is simply conjecture to ascribe larger thighs to hunters, and suggest they exercised more than farmers. I seriously doubt that typical ancient hunters engaged in anywhere near the duration or intensity of exercise of modern day marathon runners. There is a mystique that hunting is an exhausting endurance event probably perpetrated by NatGeo -type specials on Kalahari Kung hunters who attempt to survive in a very marginal environment . This is a totally atypical hunter-gather environment as are almost all modern hunter-gather environments. They have been driven out of their “happy hunting grounds” by farmers!!! Even if the data is “correct” does it (in part) mean that 700 year old farmers had terrible nutrition, rather than needing to exercise less than hunters.

  • dak kol

    Hand-In-Hand with idleness comes over-cooked and processed foods with much of the nutritional benefit lost in “hard cooking”.

    Most raw food, like our bodies, is very perishable. When raw foods are exposed to temperatures above 118 degrees, they start to rapidly break down, just as our bodies would if we had a fever that high. One of the constituents of foods which can break down are enzymes. Enzymes help us digest our food. Enzymes are proteins though, and they have a very specific 3-dimensional structure in space. Once they are heated much above 118 degrees, this structure can change. Once enzymes are exposed to heat, they are no longer able to provide the function for which they were designed. Cooked foods contribute to chronic illness, because their enzyme content is damaged and thus requires us to make our own enzymes to process the food. The digestion of cooked food uses valuable metabolic enzymes in order to help digest your food. Digestion of cooked food demands much more energy than the digestion of raw food. In general, raw food is so much more easily digested that it passes through the digestive tract in 1/2 to 1/3 of the time it takes for cooked food.

    Eating enzyme-dead foods places a burden on your pancreas and other organs and overworks them, which eventually exhausts these organs. Many people gradually impair their pancreas and progressively lose the ability to digest their food after a lifetime of ingesting processed foods.

    But you certainly can steam and blanch foods if you want your food at least warm. Use a food thermometer and cook them no higher than 118 degrees Fahrenheit. Up to this temperature, you won’t be doing too much damage to the enzymes in food.

    • frenchie mama

      Please read up on the mineral Boron;-) Up until recently, and I think very much like you about diet, I had no idea about Boron and what its lack meant to our bodies.

    • geekyneek

      Astounding. Not sure if you’re trolling or just evangelising about your badly thought out dietary beliefs. Please learn some basic dietary science before proselytising this sort of opinion.

      “Enzymes are proteins” – this is possibly the only accurate statement above. Proteins and Enzymes are very highly specific to their purpose, each has a specific role to perform and the proteins that perform one function in our own bodies can be completely different from those that perform the same functions in something that we eat as food.

      For this very reason, we use protease enzymes in our digestive systems, created by our own bodies, to break down any foreign enzyme or protein in our food into it’s constituent amino acids and associated compounds, which will then be used where needed in our bodies to be built into a protein structure that we need, be that in bone, muscle, enzyme or whatever else. In fact, should any foreign protein or enzyme actually reach our bloodstream without being broken down, the body will attack it with an immune response.

      Between the Protease (protein digestion), Amylase (sugar digestion), Lipase (fat digestion) along with the more minor but still very important enzymes in our digestive tract (all created by your body – not adopted whole from your food) all foodstuffs are broken down into usable building blocks for your bodies use.

      Somewhat humorously, the pancreas produces (among many other things) trypsin and chymotrypsin which takes apart the remainders of any protein (including foreign enzymes) after protease has acted upon it, in order to finish it’s digestive process, so the best way to, as you say “place a burden on the pancreas” is to make the digestive system have to work extra hard to break down protein. The easiest way to do this? Don’t fully cook your food…

  • Maxmilliana

    The main thing that changed since the beginning of agriculture is the consumption of large amounts of grains. I would look to that to see what effect it had on bone density. I think agricultural workers certainly did/do lots of weight bearing work, which should strengthen bones, and much of the population was engaged in this work until very recently.

    • Sherry Sparks

      I agree! Funny that there’s no mention of grain consumption and related high blood sugar as the cause of decreased bone density.

    • Scot Lyf

      how bout bone density of Inuit, Australian aboriginals, and other hunter gatherer populations?

    • frenchie mama

      its the lack of the mineral Boron in the soil now. See my post above:-) A big light bulb moment and a change in my family’s diet now has made a huge difference.

  • frenchie mama

    Its the lack of the mineral Boron in the food supply. Boron from
    modified soils are now blocked. Ask a farmer who practices soil
    modification. (I know a few) Adding this and that for pests etc.
    **Boron
    balances Calcium and where the body puts it into the body. It should be
    put into the bones and teeth etc., but its not being sorted properly.
    Without Boron it goes into places in the body it’s not needed, and
    possibly dangerous. Arteries, deposits in joints etc.he cells cannot
    pump it out well and thus it builds inappropriately.
    Pesticides and
    GMO bred plants with pesticide genes and sprays (see average corn for
    example) prevent Boron from being absorbed by the plant. Thus we do not
    eat it. A mistake was made in their science of the importance of Boron
    uptake.
    Boron was what was used for pest control by farmers up until modern pesticides and the plants geared to work with them.
    Boron
    also acts as a natural antibiotic. Kills bad bacteria in the plants and
    thus in so much, humans. It also for some reason helps Arthritis.
    Countries with the lowest Boron in their diets have the HIGHEST Chronic
    Pain rates. Research it.
    Also, it balances hormones and the thyroid.
    It kills chronic BV unlike anything else, and really Bacterial
    infections generally in the right balanced amount.
    People should research it thoroughly and please read many studies. Educate yourself.

  • auntiegrav

    Bone density correlates with brain density. The more we sit, the less we think.Civilization isolates people from the risks and interactions of the environment which spawned us, which means that the more we pursue the comforts of civilization, the less we are connected to reality. Humanity is suffering from a severe reality deficit these days in both physical and mental adaptations.

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