Subject: The Forgotten Part of Bone

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The Forgotten Part of Bone

" Susan Lark, M.D. " <drlarkbroadcast1 Add

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Wed, 31 Mar 2004 00:18:28 -0500

 

 

 

 

 

In this update:

• The Forgotten Part of Bone

• Bone's Breakdown and Remodel Process

• The pH Connection

• Healthy Hint: Bone Mineral Density Tests

 

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March 31, 2004

Dear Joann,

 

With half of all American women at high risk for developing low bone

density and osteoporosis, it is essential that your bones receive

adequate preventive care and support. Unfortunately, today's

conventional approach—calcium and vitamin D supplements or anti-

resorptive drugs (such as Fosomax)—is an overly-simplified approach.

 

The fact is one-third of your bone weight is made up of a protein

matrix, which I refer to as the bone matrix. It contains a variety

of minerals and nutrients, only one of which is calcium. And even

though physicians learn this during their medical training, many

treat their patients as if they were walking around on calcium

sticks. If this were the case, your bones would be so brittle that

they would snap every time you fell down or bumped into an object.

 

To truly treat and prevent osteoporosis, you can't overlook the

complex structure, because this often " forgotten part " of bone works

with a variety of minerals to give your bones their strength and

resilience.

 

The Forgotten Part of Bone

 

The bone matrix comprises 30 percent of your bone's weight. This

flexible, honeycombed structure consists mainly of collagen fibers,

plus chondroitin sulfate and hyaluronic acid. Another 70 percent of

your bone contains minerals that attach to the bone matrix. While

these minerals consist mainly of calcium and phosphates, other

minerals such as sodium, magnesium, copper, potassium, zinc, and

manganese are also present. Here, the whole is definitely greater

than the sum of its parts—the collagen imparts flexibility and the

crystalline minerals provide rigidity and strength. That's how your

hip can sustain up to 600 pounds of force, and still manage to twist

and bend without breaking!

 

Bone's Breakdown and Remodel Process

 

Many women don't realize that bone is a living, changing tissue.

Bones are constantly breaking down and rebuilding. In fact, 20

percent of your bone mass is replaced every year. The breakdown (or

resorption) phase begins when cells called osteoclasts detect a

crack in the crystalline structure of your bone. Once the

osteoclasts have broken down enough bone to create a small hole,

they die, and a new team of cells called osteoblasts takes over.

 

Osteoblasts are responsible for producing both the collagen fibers

and proteoglycans—large molecules that become a gelatinous substance

consisting primarily of chondroitin sulfate and a protein core. This

enables the bone matrix to be more resilient and flexible, thereby

enabling the bone to withstand physical trauma and injury. The

process of breaking down and repairing these small fissures

typically takes three to six months.

 

Until about age 20, your osteoblast activity exceeds your osteoclast

activity, so bones get naturally larger and stronger. Then there is

a period of stability that lasts about 15 years. After 35,

osteoblast activity in women starts to decline at a rate of about

one percent a year, until perimenopause, when it decreases as much

as three or four percent per year through menopause. The loss drops

back to the one percent or so annually for post-menopausal women.

 

Bone loss occurs when the breaking down activity of the osteoclast

is greater than rebuilding activity of the osteoblast.

Pharmaceutical drugs, such as Fosomax, work to halt osteoclast

activity, theoretically restoring balance to the remodeling process.

The problem is that when the breakdown process is stopped, you are

left with bone that is filled with hairline cracks that should have

been rebuilt. This means that over time, your bones become brittle.

Similarly, estrogen slows the rate of resorption and the likelihood

of fractures.

 

On the other hand, exercise, especially weight-bearing, is a great

way to increase osteoblast activity. Physical stress creates minute

electrical charges within the bone matrix, which spark your

osteoblasts into action.

 

The pH Connection

 

The osteoclasts secrete an acid that dissolves old bone, which has

an effect on your pH balance. When your blood and tissues are pushed

out of their slightly alkaline state, they instruct the osteoclasts

to break down more bone. This releases calcium and other alkaline

minerals from the disintegrated bone into the bloodstream, which in

turn helps regulate pH balance. Remember, your bones not only serve

to support your body, they also are called upon constantly to donate

their mineral reserves to neutralize excess acid in your blood.

 

Even when your acid load is tempered by adjusting your diet and

other high-acid factors, the body continues to make daily " mineral

withdrawals " from your " bone bank " to neutralize acid by-products of

metabolism and stress. Whether your bones can afford this will

depend on their mineral reserves.

 

In my next eLetter, I explain how you can maintain a strong bone

matrix and provide nutritional recommendations. Until then, you can

get information on joint health by visiting my Web site at

drlark.com.

 

 

Here's to your health!

 

 

Susan M. Lark, MD

 

 

P.S. In the April issue of my newsletter, The Lark Letter, I discuss

the health benefits of giving to others. I also invited Kat James to

share more beauty tips with you. And I talk about the different

types of sugar substitutes and tell you which ones I recommend. If

you are not a r and you would like to receive this issue,

be sure to by April 8, 2004 by calling 877-437-5275 or

clicking here. You don't want to miss it!

 

 

 

 

Bone Mineral Density Tests

 

An inexpensive and non-invasive home urine test that measures the

stability of your bone matrix can be used to assess if the collagen

in your bone matrix is being broken down too rapidly. Higher than

normal levels of deoxypyridinium (D-pyd) and pyridinium (Pyd),

collagen crosslinks that are released in your urine as bone breaks

down, can indicate if bone is being lost at a greater rate than your

body can replace it. A number of laboratories perform this test,

including:

 

MetaMetrix Medical Labs

800-221-4640 or

www.metametrix.com/Testing%20Services/

 

Ostex International

800-996-7839 or

www.ostex.com/Products/

 

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