Monthly Archives: October 2007

Move Dem Bones

Move Dem Bones

Competency # 4 Activity

Reference: Karsenty et al, Cell, August 2007

Those old dry bones of yours may have a very interesting role to play in keeping you healthy.  You thought your bones were all about holding your body together.  Well, just this week we find out that your bones are now all about holding your metabolism together.  Your bones are actually an endocrine organ.  They secrete hormones!  This is a fascinating story.

A researcher at Columbia Univesity, Gerald Karsenty found that fat cells secrete a hormone that influences bone forming cells called osteoblasts.  Osteoblasts are responsible for forming new bone.  They are active in remodeling and shaping your bones in response to fractures, but also in response to daily use.   The more you use a bone, the more it gets stronger in response to the strains you put on it.  Follow me?  For years now, we have known that osteoblasts make a protein called osteocalcin.  Only osteoblasts make it.  We just didn’t know exactly what it did.

Now, Dr. Karsenty developed a line of mice genetically engineered to make more or less osteocalcin.  The deficient mice had low levels of insulin and very poor response to insulin in their fat cells.  The mice with extra osteocalcin were skinny, even on a high calorie diet.  And their tissues were very sensitive to insulin.  The osteocalcin made the pancreas ramp up and make lots of extra insulin producing cells.  And, it made fat cells put out a hormone called adiponectin.  Adiponectin makes you insulin sensitive.

Why is all this important?  Actually, it’s not just important, it’s huge.  It unlocks a major key to understanding diabetes.   Sixty percent of us are overweight, and at risk of getting diabetes.  The hallmark of “metabolic syndrome”, or prediabetes, is the gradual decline in our sensitivity to insulin.  And humans, with pre-diabetes, or metabolic syndrome, are known to have low levels of osteocalcin.  That was chalked off to coincidence.

Now, osteocalcin could be a treatment for diabetes, if one could make it and purify it, because it would be a great way to use the natural mechanisms of your body to make you more insulin sensitive and thereby control your blood sugar better.  That’s a great idea, if you want to spend $ 200 a month buying an expensive medicine.

Let’s go down a different road.  This is conjecture, as the science hasn’t been established yet, but the pieces all fit.  When you exercise, you move blood through your body, including your bone marrow.  You flush out more osteocalcin from your marrow spaces where your osteoblasts are.  The normal use of your bones makes them remodel and reshape themselves in response to your usage, and put out more osteocalcin.  We’ve known that exercise controls your blood sugar, more than just the calories you use.  Now we know why…  And we know that exercise, of any kind, helps diabetes.  And exercise is the key to losing weight and keeping it off.  Conjecture: exercise is the key to weight control because you flush osteocalcin out of your bones with all that extra blood flow.  It makes your fat cells store less fat and release more adiponectin.  You burn some calories.  But your metabolism gets better because osteocalcin rampus up the good stuff.  Your health improves.   Your bones are “glands” and make hormones.  Fascinating.

WWW.  What will work for me?  Exercise is where it’s at.  I am walking around the new pond in our village every night we can, except when the mosquitoes get too monstrous.  Can I use that as an excuse to get my treadmill greased up?  I’m moving into Stage 3 of change.  (Remember: Stage 1 of change is DENIAL.  Stage 2 is THINKING.) I’m PLANNING to exercise.   That’s three.   By trying a little, sooner or later, I’ll move into Stage 4, and actually start exercising.   Just not yet.  How about you?  Next week.  How much should I exercise?  The new standards have just been published.  Move them bones.  There’s evidence!

Salt’s at Fault

Salt’s at Fault

Competency # 16  Minerals

Reference: He, Ogden et al JAMA, Dec 1999;  Cook and Cutler:  BMJ April 20, 2007

Let’s talk salt.  It’s one of America’s four main food groups: the others being chocolate, sugar and fat.  And that’s why we are dying like flies from cardiovascular disease.  This is the story.  Salt kills, not just by making high blood pressure, but by also being a direct risk for heart attack.  Drs. Cook and Cutler followed up on three quarters of the patients from prior large randomized studies that had compared the short-term effects of salt reduction.  Those trials were conducted in 1987-1995.  Now, 12 years later long-term follow up of those patients was conducted to see if there were measurable long-term benefits from reducing salt for 18 months.  There was.

Yes.  Plain and simple.   This is the nail in the medical coffin for salt intake.  The long-term study showed that you can reduce your risk of heart attack, independently of everything else, by 25% by reducing salt in your diet.  We know that salt causes high blood pressure and is a risk factor for stroke.  We can now say unequivocally that it’s part of the cause of heart attack too.   It’s effects are long-term, and now conclusive.  Darn it.  I love salt.

How does it work?  Your blood is basically salt water.   .9% salt water to be medically exact.  If you force feed yourself salt, your body has to protect the salt concentration in your blood and it does so by making you feel very thirsty and drinking more water.   Your blood volume expands.  Your blood vessels are like a large water balloon and expand too.   And like the balloon, your blood pressure rises along with the expansion.  When you eat that salty meal, your weight can go up 5 pounds in a day, and it then takes three days of eating less salty meals to lose all that “water weight”.  You can wash it out faster by drinking tons of water, but it takes a couple of days.

We are eating five to ten times more salt than we need, or used to eat.  We do need salt.  A tiny bit.  If we do sweaty work, we need a tiny bit more.  Our bodies evolved to crave it because sodium, the guilty chemical part of salt, is rare in nature.  Our grandparents had diets with roughly one molecule of sodium for every eight molecules of potassium.  Now we are eating four of sodium for every one of potassium.  That’s a complete reversal of the ratio of those two vital “salts”.  The food industry knows that adding sodium to food makes us crave it more.  We just can’t help but nibble on salty foods: chips, pretzels, fried chicken, burgers…and the salt is part of the puzzle of why we are having so many heart attacks.

WWW:  What Will Work for Me?  Now I know.  That’s step one.  I’m trying to get in the habit of not adding salt, ever.  I pick up pepper now at the restaurant and pepper my food.  But Tabasco sauce is salt solution and is soooo good.  And soy sauce makes Japanese food.  Can I do the sushi with just the ginger and not the soy sauce?  I’m trying it out.   And get that bag of pretzels away from me.  Just don’t keep them around.  My heart needs me.