Why monkeys do not get osteoporosis

When med­ical researchers want to study a dis­ease that affects human beings, they try to find an “ani­mal mod­el” of the dis­ease. This means find­ing the same dis­ease affect­ing a dif­fer­ent species, espe­cial­ly a species that can eas­i­ly be stud­ied in a lab­o­ra­to­ry. At first, they hoped that they would find osteo­poro­sis in mon­keys. Like women, mon­keys have a month­ly men­stru­al cycle, and some mon­keys even­tu­al­ly go through menopause. They even lose some of the cal­ci­um from their bones after menopause. Yet mon­keys don’t get osteo­poro­sis after menopause, not even if they go through menopause ear­ly from hav­ing their ovaries removed.


So why don’t mon­keys get osteo­poro­sis? An even bet­ter ques­tion is this: why is osteo­poro­sis so rare in most of the world’s pop­u­la­tions? Why is it so com­mon in places like the Unit­ed States and Scan­di­navia? In par­tic­u­lar, why is it com­mon in the same pop­u­la­tions that get heart dis­ease?

Osteoporosis is largely dietary

More animal protein, more osteoporosis

If you want to see how com­mon osteo­poro­sis is in a pop­u­la­tion, look at the num­ber of elder­ly women in that pop­u­la­tion who break a hip. This involves some com­pli­cat­ed arith­metic, because you have to adjust for the num­ber of elder­ly women in the pop­u­la­tion. But once you run those num­bers, you get an amaz­ing result. The more ani­mal pro­tein a pop­u­la­tion con­sumes, the high­er its risk of osteo­poro­sis is. Women who get their pro­tein from plants instead of ani­mals are much less like­ly to get osteo­poro­sis. You can see this same rela­tion­ship when you com­pare dif­fer­ent coun­tries with each oth­er and when you study the eat­ing habits of women with­in the same pop­u­la­tion. When you keep get­ting the same results, even when you ask the ques­tion in dif­fer­ent ways, you can be con­fi­dent that you’ve found the truth.

It’s clear that a diet that’s rich in ani­mal pro­tein caus­es osteo­poro­sis. The hard part is fig­ur­ing out why. Is there some­thing par­tic­u­lar­ly dan­ger­ous about ani­mal pro­tein? Or is there some­thing ben­e­fi­cial about plant foods as a whole? Could the answer to both ques­tions be yes?

The pro­teins in ani­mal tis­sue tend to con­tain more of the sul­fur-con­tain­ing amino acids methio­n­ine and cys­teine than do the pro­teins of plants. This means that your body pro­duces more sul­fu­ric acid (bat­tery acid!) when it burns ani­mal pro­tein than when it burns plant pro­tein. As a result, eat­ing ani­mal pro­tein pro­duces an excess acid load in the body. This acid load is called meta­bol­ic aci­do­sis. To buffer all that excess acid, your body some­times bor­rows some of the cal­ci­um from your bones. You will then end up los­ing a lot of cal­ci­um through your kid­neys. This explains why peo­ple who eat a lot of ani­mal pro­tein are at increased risk for both bone loss and kid­ney stones. It also explains why mon­keys, which are plant-eaters, are remark­ably free from osteo­poro­sis, even after menopause.

More fruit and vegetables, less osteoporosis

The more fruit and veg­eta­bles peo­ple eat, the health­i­er they tend to be. A low risk of osteo­poro­sis is only one of the many ben­e­fits of eat­ing fruits and veg­eta­bles.

There’s less sul­fur in plant pro­teins than in ani­mal pro­teins. As a result, you’d get less meta­bol­ic aci­do­sis if you get your pro­tein from plants instead of ani­mals. Even bet­ter, if you eat lots of veg­eta­bles and fruit, you’ll neu­tral­ize the acid from the plant pro­teins. Veg­eta­bles and fruit con­tain nat­ur­al antacids: not only do they con­tain alka­line min­er­als, such as potas­si­um, mag­ne­sium, and cal­ci­um, they often con­tain organ­ic acids that get bro­ken down into water and bicar­bon­ate (as in bak­ing soda!). That’s why most fruits and veg­eta­bles have a net alka­lin­iz­ing effect on the blood and urine. (One excep­tion is cran­ber­ries, which con­tain an organ­ic acid that doesn’t get bro­ken down before it pass­es into the urine.)

Besides con­tain­ing nat­ur­al antacids, veg­eta­bles and fruits may con­tain oth­er nutri­ents that are impor­tant for the health of the bones. Exam­ples include vit­a­min K and trace min­er­als such as boron.

More calcium, more osteoporosis!!!

We know that eat­ing ani­mal pro­tein caus­es an acid load that can rob our bones of cal­ci­um. Can we com­pen­sate for this prob­lem by eat­ing more cal­ci­um? Unfor­tu­nate­ly, high cal­ci­um intakes seem to make the prob­lem worse, not bet­ter.

When­ev­er I pick up a women’s mag­a­zine these days, I see arti­cles and adver­tise­ments urg­ing me to eat more high-cal­ci­um dairy foods and to take cal­ci­um sup­ple­ments, in the hopes of pre­vent­ing osteo­poro­sis. Yet when I look at the sci­en­tif­ic research, I find that pop­u­la­tions who eat low-cal­ci­um diets are less like­ly to get osteo­poro­sis than pop­u­la­tions who eat high-cal­ci­um diets. Extra cal­ci­um seems to make the prob­lem worse, not bet­ter!

When I look at the sci­en­tif­ic research, I find that it’s prac­ti­cal­ly impos­si­ble to find any­one who got sick from eat­ing a plant-based diet that’s low in cal­ci­um. The peo­ple who have trou­ble with cal­ci­um bal­ance are the ones who are eat­ing too much ani­mal pro­tein, and too much cal­ci­um!

The human body is actu­al­ly very good at main­tain­ing cal­ci­um bal­ance on a rel­a­tive­ly low-cal­ci­um, plant-based diet. Peo­ple get into trou­ble when they eat lots of ani­mal pro­tein. They get into even more trou­ble when they also eat lots of cal­ci­um. That’s because peo­ple who eat lots of cal­ci­um don’t use cal­ci­um effi­cient­ly. If they did, they would either turn to stone or die of cal­ci­um poi­son­ing. Unfor­tu­nate­ly, their bod­ies get so used to wast­ing cal­ci­um that they for­get how to store it cor­rect­ly.

Mark Heg­st­ed, who was a researcher at Har­vard Med­ical School and one of the world’s fore­most experts on cal­ci­um in nutri­tion, warned us back in 1986 that osteo­poro­sis is not due to cal­ci­um defi­cien­cy, and that in fact the pop­u­la­tions that are sus­cep­ti­ble to osteo­poro­sis are the rich West­ern indus­tri­al­ized soci­eties where peo­ple eat lots of ani­mal pro­tein and lots of cal­ci­um. Eleven years lat­er, the Study of Osteo­porot­ic Frac­tures showed that the women who were using cal­ci­um sup­ple­ments were more like­ly to break a bone. The researchers couldn’t rule out the pos­si­bil­i­ty that the cal­ci­um sup­ple­ments were actu­al­ly mak­ing the prob­lem worse!

What about bone mineral density (BMD)?

Women’s mag­a­zines nowa­days are filled with arti­cles that urge women to get their bone min­er­al den­si­ty test­ed, and to take pre­scrip­tion drugs to boost their bone min­er­al den­si­ty. These arti­cles leave out an impor­tant fact. Bone min­er­al den­si­ty is just a mea­sure of how white your bones look on an x-ray image. It doesn’t tell you much about how strong your bones are. For exam­ple, a stick of chalk would look stark white on an x-ray image. So would chalk dust. Yet nei­ther of those is very strong. Bone is hard­er than chalk dust and hard­er to break than chalk because the min­er­al crys­tals in bone are embed­ded in a tough matrix made of car­ti­lage.

What real­ly mat­ters, when push comes to shove, is how strong the bones are. The bone min­er­al den­si­ty mea­sure­ments don’t tell us the whole sto­ry. Unfor­tu­nate­ly, many of the rec­om­men­da­tions that are being made for the pre­ven­tion or treat­ment of osteo­poro­sis are based on how they affect bone min­er­al den­si­ty, not on how they affect the risk of frac­ture. There is seri­ous con­cern that some treat­ments that make the bones look bet­ter on an x-ray may also be mak­ing them more brit­tle, and more like­ly to break.

How to prevent osteoporosis

Back in 1986, Mark Heg­st­ed warned us that the con­ven­tion­al advice for pre­vent­ing osteo­poro­sis might be mak­ing things worse, not bet­ter. For­tu­nate­ly, there is some gen­er­al advice that seems to be help­ful.

Eat plants, not animals

When researchers from the World Health Orga­ni­za­tion stud­ied the prob­lem of osteo­poro­sis, they came up with two dif­fer­ent sets of rec­om­men­da­tions: one for places like Europe and North Amer­i­ca, where peo­ple eat a lot of ani­mal pro­tein and osteo­poro­sis is com­mon, and a dif­fer­ent one for places like Asia and Africa, where peo­ple eat much less ani­mal pro­tein and osteo­poro­sis is rare. In oth­er words, you can put your­self in a much low­er risk cat­e­go­ry for osteo­poro­sis just by cut­ting the ani­mal pro­tein out of your diet. The more fruit and veg­eta­bles you eat, the health­i­er your bones and the rest of your body will be.

Go outside and play

The human body is designed for an active, out­door lifestyle. Yet many of us today live as if we were designed to be cave-dwelling slugs. Our health suf­fers as a result. Our mus­cles and bones dete­ri­o­rate from lack of use, and we might end up with a defi­cien­cy of vit­a­min D.

Every­one knows that exer­cise makes your mus­cles stronger, but they might not real­ize that it also helps to make the bones stronger. By putting stress on the bones, exer­cise helps to stim­u­late the bone-remod­el­ing process. This helps to reju­ve­nate the bones, and to strength­en them where nec­es­sary. Exer­cise also helps improve bal­ance, flex­i­bil­i­ty, and coor­di­na­tion, so that peo­ple are less like­ly to fall and injure them­selves. This improve­ment in gen­er­al fit­ness can decrease the risk that some­one with osteo­poro­sis will fall and break a hip.

Spend­ing some time out­doors can also ensure that you will get enough vit­a­min D to have strong bones and a healthy immune sys­tem. Vit­a­min D is actu­al­ly a pow­er­ful hor­mone that is pro­duced in your skin when the skin is exposed to the ultra­vi­o­let light in bright sun­shine. Peo­ple who avoid sun­shine, or who use too much sun­screen, could end up with a defi­cien­cy of vit­a­min D.

In chil­dren, a severe defi­cien­cy of vit­a­min D caus­es a defor­mi­ty called rick­ets. Vit­a­min D defi­cien­cy dur­ing ges­ta­tion and ear­ly child­hood might also increase the risk of autism. In adults, a severe defi­cien­cy of vit­a­min D can cause a bone soft­en­ing called osteo­ma­la­cia. It can also pro­duce a painful syn­drome that mim­ics fibromyal­gia.

Light-skinned peo­ple at the lat­i­tude of Boston, Mass­a­chu­setts, can gen­er­al­ly get enough vit­a­min D from just get­ting a few min­utes of noon­day sun­shine on their face and fore­arms dur­ing the spring, sum­mer, and autumn. Dark-skinned peo­ple and those who live fur­ther north might want to have their doc­tor mon­i­tor their vit­a­min D lev­els.

Follow a healthy lifestyle

Although we think of osteo­poro­sis as a dis­ease of elder­ly women, it also occurs in elder­ly men. It can also occur in younger peo­ple, often as a result of a hor­mon­al imbal­ance or from the use of cor­ti­sone-like drugs for the treat­ment of var­i­ous dis­eases. For­tu­nate­ly, you can reduce your risk of those same dis­eases by fol­low­ing the same lifestyle tips that help to pre­vent osteo­poro­sis:

  • Eat plants, not ani­mals
  • Go out­side and play

A low-fat, plant-based diet is the first line of defense against many kinds of chron­ic degen­er­a­tive dis­ease. You might be able to reduce your risk of osteo­poro­sis even fur­ther by doing the fol­low­ing:

  • Don’t smoke
  • Don’t eat too much salt
  • Lim­it the intake of alco­hol and caf­feine
  • Lim­it the intake of cola bev­er­ages, which con­tain phos­phor­ic acid

The first step in man­ag­ing any dis­ease is to remove the cause. If you already have a diag­no­sis of osteo­poro­sis, your first step in man­ag­ing it will be to cor­rect your diet, so as not to make the prob­lem any worse. You and your doc­tor will also have to weigh the risks and ben­e­fits of the var­i­ous avail­able treat­ments.