Sharks, Cartilage, Cancer, Bones, Vitamin D and Naked Mole Rats

[McCamy Taylor]

Here are some random musings on cancer and its relationship to bone metabolism. No cancer cures here, just starting points for further study.

I. Sharks Do Get Cancer

In 1992, Dr. I William Lane published the book Sharks Don't Get Cancer: How Shark Cartilage Could Save Your Life. His theory was simple. Sharks do not get cancer. Sharks have lots of cartilage. Cartilage is tissue in which blood vessels do not grow. Cancer needs lots of blood vessels to survive. Kill sharks and consume their cartilage and you will not have cancer.

http://www.scientificblogging.com/science_paradise/busting_marine_myths_sharks_do_get_cancer



In fact, sharks do get cancer---though not as often as vertebrates. And eating shark cartilage is extremely unlikely to cure your cancer, as a lot of shark lovers keep trying to tell us.

However, a couple of recent medical studies make me wonder if there is something to the notion that sharks have less cancer because they are cartilaginous fish. While you and I and most of the fish in the sea and birds in the air and creatures that walk the earth have bones, sharks have none (except for their teeth). Maybe what sets sharks apart is not their cartilage. Maybe it is their lack of bone.

What does bone have to do with cancer? Two compounds which promote bone health are now being studied for their possible effect in preventing cancer.

In recent years, there have been a number of studies which have suggested that Vit. D may inhibit the formation of cancer, particularly colon cancer. In one study, those with the highest Vit. D levels had a lower colon cancer incidence than those with the lowest Vit. D levels.

http://www.ncbi.nlm.nih.gov/pubmed/17296473

Another study found the same effect for breast cancer.

http://www.sciencedaily.com/releases/2007/02/070206100608.htm

Recently, bisphophonates (such as Fosomax) were found to be associated with lower rates of breast cancer.

http://www.bloomberg.com/apps/news?pid=newsarchive&sid=att6V4eOZMgw

Bisphosponates work by inhibiting the cells which breakdown bone (called osteoclasts). Bone in the human body is constantly being remodeled. It is broken down and then fixed back up by osteoblasts. Bisphosponates also increase the number and activity of osteoblasts. Therefore, it overlaps with Vitamin D in terms of function. For example,
the bone protein osteocalcin, can be used as a biologic marker for new bone formation. More new bone formation, more osteocalcin.

http://en.wikipedia.org/wiki/Osteocalcin

Bisphosphanates increase osteocalcin levels.

http://www.ncbi.nlm.nih.gov/pubmed/15046901

Vit D is necessary for osteocalcin formation.

http://www.jbc.org/content/265/35/21881.full.pdf

If you look back at the cancer studies above, folks who are most deficient in Vit D. seem to have the most cancer risk. Could Vit. D deficiency cause some chemical or hormone response in the body which in turn promotes tumor cell growth? Could bisphosponates prevent that chemical or hormone response which promotes tumor cell growth?

Just raising the rate of bone turnover is not enough to prevent cancer. Physiologic administration of growth hormone (to people who do not have enough) also increases bone turnover and osteocalcin levels, but no studies have suggested that growth hormone slows down cancers.

http://www.ncbi.nlm.nih.gov/pubmed/8967668

The link---if there is one---between having a skeleton and getting cancer is probably more complicated than that.


II. Naked Mole Rats Don’t Get Cancer

I am going to change gears here. While sharks occassionally get cancer, there is one animal that truly is cancer free. I refer to the naked mole rat.



You can read about this little guy who lives underground in a society a lot like an ant or bee colony here:

http://en.wikipedia.org/wiki/Naked_mole_rat

These guys can not feel pain. And they live for an almost impossibly long 28 years (other rats live 2-4) and they do not age. They can tolerate extremely low levels of oxygen. And, unlike most rats, they never get cancer. Wiki claims that this is because the have a combination of the p27 gene all mammals have and a unique p 16 gene.

Note that Vit D. in lab studies can increase the activity of the cancer inhibiting p 27 gene.

http://www.ncbi.nlm.nih.gov/pmc/articles/PMC2228067/pdf/brjcancer00171-0062.pdf

Naked mole rats are one of the few vertebrates that do not make Vitamin D.

http://en.wikipedia.org/wiki/Vitamin_D#cite_note-12

If you feed naked mole rats Vitamin D, their metabolic rate goes up. The naturally low metabolic rate of these animals has been credited as the source of their longevity.

http://www.ncbi.nlm.nih.gov/pubmed/8384476

How on earth does a mammal regulate its calcium without Vit. D? Good question. Let me know if you find an answer. Naked mole rats do not have insulin either. Maybe they have something better, something that keeps their bones strong and their arteries young without raising their metabolic rate. Maybe that something is also what keeps them from getting cancer.

Please, whatever you do, don’t start eating them or taking them in capsule form. I can pretty much guarantee that will not do anything except contribute to the extinction of the naked mole rat. You can not eat an animal’s brains to gain its knowledge, and you can not chew on an animals cartilage to acquire its unique metabolism.

[Newest Reality]

1. Ah, a deep, metaphysical question answered for me!

I shall reincarnate as a naked mole rat! That's just what I have been searching for for so long.

Thanks!

[Ken Burch]

2. Here's what you'll look like, then:

[G_j]

3. great post

I'm still reading! Muchos Gracias

[planetc]

4. In northern climes, we don't get as much sun as southerners, and thus ...

we're not getting as much sunlight-induced vitamin D formation internally. I think I'm right in saying that the body makes its own vit. D, from sunlight? It's therefore worth our time to ask our doctors what our blood level of D is. I recently did this, found a cooperative doctor, and found that mine was more than adequate. I had started taking vitamin D as a replacement for Fosamax, which had been prescribed for osteoporosis, but which didn't agree with my body much. Having had some unpleasant experiences over the years from prescription drugs, I have also been following the work of Dr. Susan Brown, who has a Better Bones project, and feels that we can address the bone health problem in other ways than the standard Actonel or Fosamax. What I noticed immediately is that if I take some extra vitamin D, I sleep better too.

Disclaimer: I'm doing two experimental things here: not taking Fosamax, and taking D as a possible or partial replacement. This is a non-scientific experiment, and should not be tried without at least a tiny bit of medical knowledge as justification. What I feel bottom line about vit. D is that it's probably not doing any harm, and may be doing some good. Meanwhile, the standard prescription drugs for osteoporosis or osteopenia have side effects for some patients, and they're rather unpleasant.

If vit. D will also ward off cancer, so much the better: let's check out whether this is true, and why.

[kimmerspixelated]

7. EXCELLENT RESPONSE.

Kudos to you for rejecting mod. medicine. There has been a lot of good research findings behind algae based calcium for bone health. Garden of Life makes a good calcium called Raw Calcium in their Raw vitamins line.

For the naysayers who just love to jump my butt- the reason to choose alternative medicine has to do with the non-disputable fact that the body does not molecularly (sp?) recognize anything synthetic.It really doesn't know how to metabolize said drugs. Plants, herbs and minerals have the same molecular makeup as we do. Yes, caution, always.

[SocialistLez]

5. I've been taking Vitamin D faithfully for about 3 months

At first it made me VERY gassy and still does on ocassion. :blush:

If that's the price I have to pay for reducing my cancer risk, I'm fine with it.
Cancer is one of my biggest fears.

[BadgerKid]

6. Cool. Lots to think about. Thx! n/t