# African-Americans have dense bones & sink easily, Asians have porous bones & they float. T or F? **URL:** \ **Category:** Factual Questions\ **Created:** [September 11, 2013, 1:39am UTC](https://boards.straightdope.com/t/african-americans-have-dense-bones-sink-easily-asians-have-porous-bones-they-float-t-or-f/668541 "2013-09-11T01:39:46Z")\ **Posts on this page:** 20\ **Page:** 1
**Author:** ![astro](https://avatars.discourse-cdn.com/v4/letter/a/9dc877/32.png) [@astro](https://boards.straightdope.com/u/astro)\ **Post date:** [September 11, 2013, 1:39am UTC](https://boards.straightdope.com/t/african-americans-have-dense-bones-sink-easily-asians-have-porous-bones-they-float-t-or-f/668541/1 "2013-09-11T01:39:46Z")
Is this claim from [this health related website](http://www.healthcentral.com/cholesterol/home-body-fat-test-2774-143.html)true or false? > [@](#): > > The bones of African-Americans tend to be dense and so they sink easily in water. On the other hand, the bones of Asians are light and porous so they tend to float. ---
**Author:** ![RandMcnally](https://avatars.discourse-cdn.com/v4/letter/r/b782af/32.png) [@RandMcnally](https://boards.straightdope.com/u/RandMcnally)\ **Post date:** [September 11, 2013, 1:43am UTC](https://boards.straightdope.com/t/african-americans-have-dense-bones-sink-easily-asians-have-porous-bones-they-float-t-or-f/668541/2 "2013-09-11T01:43:27Z")
That… doesn’t seem right. Like, at all. ---
**Author:** ![Fear\_Itself](https://sea3.discourse-cdn.com/straightdope/user_avatar/boards.straightdope.com/fear_itself/32/19637_2.png) [@Fear\_Itself](https://boards.straightdope.com/u/Fear_Itself)\ **Post date:** [September 11, 2013, 1:46am UTC](https://boards.straightdope.com/t/african-americans-have-dense-bones-sink-easily-asians-have-porous-bones-they-float-t-or-f/668541/3 "2013-09-11T01:46:18Z")
As if Asian bones are full of air spaces, which would turn into embolisms every time you fell down. ---
**Author:** ![california\_jobcase](https://avatars.discourse-cdn.com/v4/letter/c/9d8465/32.png) [@california\_jobcase](https://boards.straightdope.com/u/california_jobcase)\ **Post date:** [September 11, 2013, 1:54am UTC](https://boards.straightdope.com/t/african-americans-have-dense-bones-sink-easily-asians-have-porous-bones-they-float-t-or-f/668541/4 "2013-09-11T01:54:30Z")
Porous bones would be filled with watery fluids such as blood. Just how much denser is solid bone, if any? Fat is more buoyant than muscle and bones. I took a swimming class back when I was skinny. I did everything well except for anything that required floating, and one assignment was to tread water in the deep end of the pool for twenty minutes. Floating was permitted if you could do it- I couldn’t and had to tread water for twenty minutes. One muscle-bound body builder dropped the class because he wasn’t buoyant enough to swim! Every stroke just pulled him under. If he tried the “dead man’s float” he sunk like a stone. I just drifted slowly down when I tried it. ---
**Author:** ![Fubaya](https://avatars.discourse-cdn.com/v4/letter/f/c2a13f/32.png) [@Fubaya](https://boards.straightdope.com/u/Fubaya)\ **Post date:** [September 11, 2013, 2:06am UTC](https://boards.straightdope.com/t/african-americans-have-dense-bones-sink-easily-asians-have-porous-bones-they-float-t-or-f/668541/5 "2013-09-11T02:06:41Z")
> [@RandMcnally](#): > > That… doesn’t seem right. Like, at all. You mean they have it backwards, right? ---
**Author:** ![Der\_Trihs](https://sea3.discourse-cdn.com/straightdope/user_avatar/boards.straightdope.com/der_trihs/32/233_2.png) [@Der\_Trihs](https://boards.straightdope.com/u/Der_Trihs)\ **Post date:** [September 11, 2013, 2:12am UTC](https://boards.straightdope.com/t/african-americans-have-dense-bones-sink-easily-asians-have-porous-bones-they-float-t-or-f/668541/6 "2013-09-11T02:12:05Z")
> [@california\_jobcase](#): > > Just how much denser is solid bone, if any? Presumably a fair amount, or birds wouldn’t have hollow bones to help them fly. That said, I’ve never heard any claim remotely like this before. ---
**Author:** ![tomndebb](https://avatars.discourse-cdn.com/v4/letter/t/b9e5f3/32.png) [@tomndebb](https://boards.straightdope.com/u/tomndebb)\ **Post date:** [September 11, 2013, 2:34am UTC](https://boards.straightdope.com/t/african-americans-have-dense-bones-sink-easily-asians-have-porous-bones-they-float-t-or-f/668541/7 "2013-09-11T02:34:02Z")
There seems to be some validity to the claim: > **[Racial Differences in Bone Strength](https://www.ncbi.nlm.nih.gov/pmc/articles/PMC1863580/)** > > Osteoporosis has been defined as a systemic skeletal disorder characterized by compromised bone strength predisposing to an increased risk of fracture. The clinical consequences of fracture include short- and long-term morbidity as well as increased... [http://jcem.endojournals.org/content/82/2/429.full](http://jcem.endojournals.org/content/82/2/429.full) ---
**Author:** ![WhyNot](https://avatars.discourse-cdn.com/v4/letter/w/c77e96/32.png) [@WhyNot](https://boards.straightdope.com/u/WhyNot)\ **Post date:** [September 11, 2013, 3:17am UTC](https://boards.straightdope.com/t/african-americans-have-dense-bones-sink-easily-asians-have-porous-bones-they-float-t-or-f/668541/8 "2013-09-11T03:17:21Z")
I don’t know if Asian bones are so much less dense that they _float_ (even most of the chicken bones don’t float), but yes, it’s true that bone density tends to be greater, and rates of osteoporosis correspondingly lower, in Americans of African descent. ---
**Author:** ![aceplace57](https://sea3.discourse-cdn.com/straightdope/user_avatar/boards.straightdope.com/aceplace57/32/3500_2.png) [@aceplace57](https://boards.straightdope.com/u/aceplace57)\ **Post date:** [September 11, 2013, 3:33am UTC](https://boards.straightdope.com/t/african-americans-have-dense-bones-sink-easily-asians-have-porous-bones-they-float-t-or-f/668541/9 "2013-09-11T03:33:57Z")
I’m not sure why, but I rarely (if ever) see African Americans in competitive swimming or diving competitions. ABC had a celebrity diving show last winter and a black football player made comments about not floating/swimming well. He struggled on that show. I wouldn’t be surprised to learn that bone density had something to do with it. ---
**Author:** ![Colibri](https://sea3.discourse-cdn.com/straightdope/user_avatar/boards.straightdope.com/colibri/32/1841_2.png) [@Colibri](https://boards.straightdope.com/u/Colibri)\ **Post date:** [September 11, 2013, 3:41am UTC](https://boards.straightdope.com/t/african-americans-have-dense-bones-sink-easily-asians-have-porous-bones-they-float-t-or-f/668541/10 "2013-09-11T03:41:26Z")
> [@tomndebb](#): > > There seems to be some validity to the claim: > [Racial Differences in Bone Strength - PMC](http://www.ncbi.nlm.nih.gov/pmc/articles/PMC1863580/) > [http://jcem.endojournals.org/content/82/2/429.full](http://jcem.endojournals.org/content/82/2/429.full) There appear to be statistically significant differences in bone density between some racial groups. However, other sites point out that the variance _within_ racial groups is greater than that _between_ racial groups. That is, one cannot predict the bone density of individuals based on racial grouping; some whites will have denser bones than some blacks. ---
**Author:** ![Lamar\_Mundane](https://avatars.discourse-cdn.com/v4/letter/l/85f322/32.png) [@Lamar\_Mundane](https://boards.straightdope.com/u/Lamar_Mundane)\ **Post date:** [September 11, 2013, 3:52am UTC](https://boards.straightdope.com/t/african-americans-have-dense-bones-sink-easily-asians-have-porous-bones-they-float-t-or-f/668541/11 "2013-09-11T03:52:46Z")
> [@aceplace57](#): > > I’m not sure why, but I rarely (if ever) see African Americans in competitive swimming or diving competitions. At least thirteen Olympic medals have been won by black athletes, including four golds. > **[Cullen Jones](https://en.wikipedia.org/wiki/Cullen_Jones)** > > Cullen Andrew Jones (born February 29, 1984) is an American former competition swimmer and Olympic gold medalist who specializes in freestyle sprint events. As part of the American team, he holds the world record in the 4×100-meter freestyle relay (long course). At the 2012 Summer Olympics, he won silver medals in the 4 x 100-meter freestyle relay and the 50-meter freestyle, as well as the gold in the 4 x 100-metre medley. > Born on Leap day of 1984 in the Bronx borough of New York City, Jones... ---
**Author:** ![california\_jobcase](https://avatars.discourse-cdn.com/v4/letter/c/9d8465/32.png) [@california\_jobcase](https://boards.straightdope.com/u/california_jobcase)\ **Post date:** [September 11, 2013, 3:53am UTC](https://boards.straightdope.com/t/african-americans-have-dense-bones-sink-easily-asians-have-porous-bones-they-float-t-or-f/668541/12 "2013-09-11T03:53:16Z")
Ah, Der Tris, human lungs don’t connect to our bones. Any porosity therein will be filled with liquids, not gas. ---
**Author:** ![njtt](https://avatars.discourse-cdn.com/v4/letter/n/ecd19e/32.png) [@njtt](https://boards.straightdope.com/u/njtt)\ **Post date:** [September 11, 2013, 3:56am UTC](https://boards.straightdope.com/t/african-americans-have-dense-bones-sink-easily-asians-have-porous-bones-they-float-t-or-f/668541/13 "2013-09-11T03:56:32Z")
Well obviously we need to throw them in the duck pond to see which floats. ---
**Author:** ![DSeid](https://sea3.discourse-cdn.com/straightdope/user_avatar/boards.straightdope.com/dseid/32/20194_2.png) [@DSeid](https://boards.straightdope.com/u/DSeid)\ **Post date:** [September 11, 2013, 3:58am UTC](https://boards.straightdope.com/t/african-americans-have-dense-bones-sink-easily-asians-have-porous-bones-they-float-t-or-f/668541/14 "2013-09-11T03:58:35Z")
I can find other sources, both original articles and brief .edu reviews like [this one](http://depts.washington.edu/bonebio/bonAbout/race.html) that support the concept that bone density is greater in Blacks than in Whites or Asians. It is still a bit of a stretch to claim that such has much to do with buoyancy. Body composition is a more critical factor: how much is fat free mass and how much is fat? Fat floats. Fat percent trumps the small difference in bone density. [This page](http://www.halls.md/bmi/newyork.htm) provides data on that. One the one hand there is more overweight and obesity among Blacks in America so a random Black person may be more like to float than a random Asian person. OTOH for a given BMI an Asian person is likely to have a higher percent of body fat, so given equal BMIs the Asian person is more likely to float. ---
**Author:** ![DSeid](https://sea3.discourse-cdn.com/straightdope/user_avatar/boards.straightdope.com/dseid/32/20194_2.png) [@DSeid](https://boards.straightdope.com/u/DSeid)\ **Post date:** [September 11, 2013, 4:01am UTC](https://boards.straightdope.com/t/african-americans-have-dense-bones-sink-easily-asians-have-porous-bones-they-float-t-or-f/668541/15 "2013-09-11T04:01:24Z")
Now why bone density varies is not immediately obvious to me … one would think with less sun getting through and lower vitamin D levels that density would be lower, not higher, in Blacks. The article speculates that there are hormonal differences. I don’t know. ---
**Author:** ![WhyNot](https://avatars.discourse-cdn.com/v4/letter/w/c77e96/32.png) [@WhyNot](https://boards.straightdope.com/u/WhyNot)\ **Post date:** [September 11, 2013, 4:35am UTC](https://boards.straightdope.com/t/african-americans-have-dense-bones-sink-easily-asians-have-porous-bones-they-float-t-or-f/668541/16 "2013-09-11T04:35:39Z")
> [@DSeid](#): > > Now why bone density varies is not immediately obvious to me … one would think with less sun getting through and lower vitamin D levels that density would be lower, not higher, in Blacks. The article speculates that there are hormonal differences. I don’t know. Weight? I know heavier people tend to less osteoporosis than underweight people, giving the bones the benefit of weight bearing and impact to stimulate the osteoblasts (if I recall my physiology classes correctly). African Americans certainly average a higher BMI than Asians. (Again, as a group, generalization, here, have this broad brush…) ---
**Author:** ![Mister\_Rik](https://sea3.discourse-cdn.com/straightdope/user_avatar/boards.straightdope.com/mister_rik/32/491_2.png) [@Mister\_Rik](https://boards.straightdope.com/u/Mister_Rik)\ **Post date:** [September 11, 2013, 5:41am UTC](https://boards.straightdope.com/t/african-americans-have-dense-bones-sink-easily-asians-have-porous-bones-they-float-t-or-f/668541/17 "2013-09-11T05:41:21Z")
> [@california\_jobcase](#): > > Porous bones would be filled with watery fluids such as blood. Just how much denser is solid bone, if any? > Fat is more buoyant than muscle and bones. I took a swimming class back when I was skinny. I did everything well except for anything that required floating, and one assignment was to tread water in the deep end of the pool for twenty minutes. Floating was permitted if you could do it- I couldn’t and had to tread water for twenty minutes. One muscle-bound body builder dropped the class because he wasn’t buoyant enough to swim! Every stroke just pulled him under. If he tried the “dead man’s float” he sunk like a stone. I just drifted slowly down when I tried it. My dad told me that, when he was in the US Marine Corps, one of his fellow basic training grunts was a guy who had no buoyancy. He’d get in the water and sink like a rock. The guy finished his 4-year term in the Marines, and then joined the Navy, where he went onto become a Navy Seal. > [@njtt](#): > > Well obviously we need to throw them in the duck pond to see which floats. She’s a witch! Burn her! Burn her! ---
**Author:** ![thelurkinghorror](https://avatars.discourse-cdn.com/v4/letter/t/7c8e57/32.png) [@thelurkinghorror](https://boards.straightdope.com/u/thelurkinghorror)\ **Post date:** [September 11, 2013, 5:56am UTC](https://boards.straightdope.com/t/african-americans-have-dense-bones-sink-easily-asians-have-porous-bones-they-float-t-or-f/668541/18 "2013-09-11T05:56:58Z")
> [@njtt](#): > > Well obviously we need to throw them in the duck pond to see which floats. [I know at least one Asian person who would float](http://en.wikipedia.org/wiki/Kiki%27s_Delivery_Service). I suppose it’s not out of the question, although this is all new to me. E.g. earwax composition and appearance in white/black people is very different than Asian/Native American. I really doubt the stereotype of “black people can’t swim” is directly related, though, and I don’t think that African-American is the term they meant to use. ---
**Author:** ![A\_nice\_guy\_with\_an\_opinion](https://avatars.discourse-cdn.com/v4/letter/a/76d3ee/32.png) [@A\_nice\_guy\_with\_an\_opinion](https://boards.straightdope.com/u/A_nice_guy_with_an_opinion)\ **Post date:** [September 11, 2013, 6:04am UTC](https://boards.straightdope.com/t/african-americans-have-dense-bones-sink-easily-asians-have-porous-bones-they-float-t-or-f/668541/19 "2013-09-11T06:04:30Z")
Asian bones are good at math? Just trying to fit in here. ---
**Author:** ![Der\_Trihs](https://sea3.discourse-cdn.com/straightdope/user_avatar/boards.straightdope.com/der_trihs/32/233_2.png) [@Der\_Trihs](https://boards.straightdope.com/u/Der_Trihs)\ **Post date:** [September 11, 2013, 6:11am UTC](https://boards.straightdope.com/t/african-americans-have-dense-bones-sink-easily-asians-have-porous-bones-they-float-t-or-f/668541/20 "2013-09-11T06:11:16Z")
> [@aceplace57](#): > > I’m not sure why, but I rarely (if ever) see African Americans in competitive swimming or diving competitions. American blacks tend to be poorer, and have less access to things like pools. They aren’t likely to ever become good swimmers if they’ve seldom or never had the chance to swim at all. [Next page](https://boards.straightdope.com/t/african-americans-have-dense-bones-sink-easily-asians-have-porous-bones-they-float-t-or-f/668541.md?page=2)