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Dear Mark: The Purpose of Body Hair and the Non-Essentiality of Dietary Cholesterol

Posted By Mark Sisson On May 27, 2013 @ 8:00 am In Dear Mark | 76 Comments

In today’s edition of Dear Mark [7], I finally field a question that has been weighing heavily on the hearts and minds of the ancestral health community: body hair. I will tell you that there has been a lot of behind the scenes chatter between big names in the community about just how to tackle this question, and until now, no one has stepped up. To be frank, no one really knew what to say. No one wanted to commit. I certainly didn’t, but then I got this email from Natasha and I realized that something had to be done. The people couldn’t wait til the roundtable discussion on chest hair scheduled for the next PaleoFX or Loren Cordain’s keynote speech at AHS 13 on the evolutionary purpose of arm hair. They needed to know why body hair exists, and they needed to know now. After that, I cover the less exciting topic of the non-essentiality of dietary cholesterol. In other words, if we can make it, why do we need to eat it? I go over why that question misses the entire point, and more.

Let’s go:

I don’t think you’ve addressed this topic yet. People, especially women, today are obsessed with hair removal in various parts of the body. Grok and Grokette didn’t shave, wax, do laser hair-removal, etc and I’m sure they grew body hair for some evolutionary purpose (protection, temperature control, etc). My question is does all this hair removal lead to adverse effects or it is simply cosmetic and harmless? I personally don’t participate in this trend, but most do.


What’s the purpose of body hair?

It may have aided in the detection of parasites, like ticks or fleas. In one study [8], subjects with a single arm shaved had bed bugs placed on both arms. Overwhelmingly, bed bugs were detected first on the hairy arm. Arm hair also seemed to impede the bugs from feeding; bugs on bare arms began biting before the bugs on hairy arms. You’d think it would be the opposite, that you’d notice them first on the bare skin, but body hairs tend to be fairly sensitive to slight movement, almost like built-in motion detection sensors. You’re going to notice a tick threading its way through your arm thatch because it’ll kinda tickle.

It may have helped thermoregulate, but I think clothing, fire, and architecture have made that mostly irrelevant. Hominids have definitely been trending toward less and less body hair over the past couple million years.

How about facial hair? Face hair protects the face [9], blocking up to 90% of UV rays. Beards block pollen and dust, reducing the symptoms of seasonal allergies, while locking in moisture and keeping the skin fresh and young-looking.

Although you didn’t mention it specifically, I think it bears mentioning that pubic hair does seem to have a purpose, too: scent wick. Human pubic regions contain apocrine sweat glands whose pheromone-rich secretions [10] are acted upon by bacteria to produce even more pheromones – chemicals that trigger a social response in other people, usually of the opposite sex. Pubic hair essentially acts as a hangout for these secretions, allowing them to to stick around a little longer so that bacteria has more time to interact with them and produce interesting pheromones, which in turn have more time to exert their effects on others (and maybe attract a mate or set into motion a shot at procreation). Without pubic hair, pheromone production will likely drop and what pheromones are produced may not have as much longevity. It’s easy to think of pheromones as “bad smells” we no longer need or want, but they are a crucial aspect of attraction that likely remain relevant (even if we don’t know it and assuming we’re dealing with people face to face). Of course, seeing as how most of us keep that region covered up, I wonder how much really “gets through.”

So no, I don’t think there are any acutely adverse effects, other than razor burn, extreme itchiness or inappropriately placed lasers. According to some [11], pubic hair removal may inflame the area, lead to microscopic abrasions, and increase the risk of infection, but I haven’t seen any official statistics showing this to be the case. You certainly want to exercise caution and minimize trauma to the area, whatever your method of removal.

Your site talks a lot about how every cell in the body can make its own cholesterol, because cholesterol is so vital to the human body. But if every cell can make its own cholesterol, then why should we (or why do we) need to eat foods with cholesterol in them? Isn’t this just another reason for choosing veganism instead? A vegan recently said to me that she is healthy because her body already produces cholesterol on its own, so there is absolutely no need for her to ingest more cholesterol. Her logic seems to make sense, since the body can produce its own cholesterol. Thoughts?


Technically, this is true for most people. But in certain cases, when cholesterol requirements are elevated or cholesterol synthesis is impaired, dietary cholesterol may be incredibly useful and perhaps even necessary.

People with Smith-Lemli-Opitz syndrome (SLOS) produce very low levels of 7-DHC reductase, an enzyme involved in cholesterol synthesis, and may need to supplement with dietary cholesterol to make up for the lack of endogenous production. However, SLOS is a recessive disorder, meaning both parents must contribute a recessive gene to their child in order for him to have it; it’s fairly rare.

As you probably already know, testosterone is made from cholesterol. Since testosterone is an anabolic hormone involved in muscle building and strength development, people engaged in strength training need more testosterone. In these populations, cholesterol supplementation (via whole eggs) has been shown to increase strength considerably [12].

All this talk misses my major point concerning cholesterol: it’s not so much that we need dietary cholesterol (although it’s clearly beneficial in certain groups and under certain contexts), but that cholesterol-rich foods also tend to be incredibly nutritious. The cholesterol itself doesn’t hurt, and it may even help, but the stuff that comes along for the ride with cholesterol is what we truly want. Let’s just go through three particularly cholesterol-rich foods that you might stumble across when going Primal.

Eggs - Not only delicious and high in cholesterol, whole eggs are also loaded with vitamin A, choline, iodine, selenium, highly digestible protein, and, depending on what the chicken ate, good levels of vitamin E, vitamin K2, and DHA.

Liver – Nature’s multivitamin, liver is rich in iron, vitamin A, copper, B-vitamins, choline, and folate. Oh, and yes, it has a decent amount of cholesterol.

Shrimp – In addition to cholesterol, shrimp is also good for selenium, iron, and a neat little antioxidant known as astaxanthin.

These are good, healthy foods by any sane measure. Because they contain some cholesterol, though, they should “be limited.” Or “avoided.” Or “minimized.”

Just marvel at the preposterousness of this line of thinking by checking out an insightful article [13] from “HealthAliciousNess.com” (those jerks totally stole my name and I had to settle for Mark’s Daily Apple) warning us to “limit or avoid” the following high-cholesterol, highly-dangerous foods: the aforementioned egg yolks, shrimp, and liver, plus squid, caviar, pate, butter, sardines, cheese, liver sausage, crayfish, and shellfish. Do those really sounds all that dangerous to you?

I don’t know. Maybe your vegan friend is magic. If her body can manufacture adequate amounts of choline, selenium, iodine, B-vitamins, folate, iron, copper, protein, vitamin A (retinol, the pre-formed animal form, the good stuff), vitamin E, vitamin K2, and DHA, then sure, any foods that contain dietary cholesterol are probably unnecessary and she’s totally correct. If not, though, if she’s like the rest of us sad sacks with our pathetic reliance on exogenous vitamins and minerals, she may derive benefit from incorporating certain cholesterol-rich foods into her diet.

As for you, don’t go vegan. The fruits and vegetables are great, but you’ll really be missing out on some nutrient-rich-foods-that-happen-to-be-high-in-cholesterol-which-isn’t-essential-but-may-actually-confer-additional-benefits-or-at-the-very-least-be-entirely-innocuous. Don’t go seeking out cholesterol, don’t buy supplementary cholesterol, don’t make scrambled caviar every morning (but only because it’s so expensive). Just don’t shy away from foods that have it.

That’s it for today. Email me your questions here [14] and I’ll try to answer them in a future Dear Mark. Grok on!

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[8] study: http://rsbl.royalsocietypublishing.org/content/early/2011/12/08/rsbl.2011.0987.full.pdf

[9] Face hair protects the face: http://worldobserveronline.com/2013/04/15/beards-keep-you-young-healthy-handsome-says-science-2/

[10] apocrine sweat glands whose pheromone-rich secretions: http://www.ncbi.nlm.nih.gov/pubmed/11577991

[11] According to some: http://www.independent.co.uk/life-style/health-and-families/health-news/physician-calls-for-an-end-to-bikini-waxing-8008628.html

[12] shown to increase strength considerably: http://www.fasebj.org/cgi/content/meeting_abstract/22/1_MeetingAbstracts/962.13

[13] article: http://www.healthaliciousness.com/articles/foods-highest-in-cholesterol.php

[14] here: http://www.marksdailyapple.com/contact/#axzz2UT5BYDXd

[15] PrimalCon New York: http://www.primalblueprint.com/product/PrimalCon_New_York_2014/Events

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