Mineralization of bone matrix is essential to living a healthy life. 99% of the body’s calcium (and other minerals) are contained in the bones and teeth. The matrix and minerals create two thirds of the bones weight, with the remainder coming from the water weight of bone. Bone cells called osteoblasts produce 85% of the collagen contained in the bone from which hydroxyapatite is created as a crystal-like matrix. In fact, it is this protein matrix that is much more essential to the health of the bone than calcium that most everyone is aware of.
The remaining 1% of calcium is involved in multiple functions, one of which is acid buffering mechanisms that assist in keeping the pH in neutral range. This is important because if lifestyles are too acidic (from poor food choices, high insulin and blood sugar and inflammatory burden from processed foods) creating a net acid excess the body will attempt to neutralize the acid by dumping calcium from bones stores into the blood. Ultimately acid excess over long periods of time contributes to demineralization and thus osteoporosis. There are graduated states of bone demineralization, the first of which is called osteopenia, defined as a reduced bone matrix up to 2.5 standard deviations below a normal 28-year-old woman. Osteoporosis is defined are demineralization more than 2.5 standard deviations.
Studies show that bone remodeling is every 5 years, and that while bone growth halts after puberty, there continues to be a balance between bone build up and bone breakdown. In test rats a variation of just .2 pH (pH is on a scale of 1 – 14) reduction caused a 500-900% loss of calcium from the rat bone. Human studies show that venous blood pH reduction from 7.37 to 7.33 resulted in significant calcium release from bone. The message clearly is that as we keep our acidity balanced by limiting correcting inflammatory issues in the body (blood sugar, insulin, poor food choices), the worst of which is sugar and sugar-forming foods like starches, we in turn spare the bone to keep its stores of calcium. AS well we realize that proper protein metabolism is required for bone health, so eating a good and regular supply of protein can contribute to bone health.
Currently osteoporosis and its related problems have become the third leading health issue and expense. It is simple to balance the underlying causes of this condition, then to demonstrate it within 6-9 months of proper nutritional repletion. All bone grows in response to stress. This is called Wolf’s Law and dictates that we should do weight-bearing exercise to promote health bone growth. If we consider the principle of bone growth and health and align ourselves in lifestyle with these principles osteoporosis no longer needs to be devastating for so many people.
The Anatomy and Physiology of Bone
Note: Fosamax-type drugs (bisphosphonates) function by blocking the breakdown of the old bone, which in turn, interferes with the rebuilding of new bone. The result – bone scan scores improve, but bone health does not.
Bone Structure
- Bone is formed from a collagen-protein matrix or framework, into which minerals deposit. This combination allows bone to be strong and hard, as well as flexible.
Bone Composition
- Bone matrix is formed from specific proteins and collagen fibers. This framework is like the steel infrastructure of a building. It constitutes about 1/3 of bone composition.
- Mineral salts deposit within the matrix, and form about 2/3 of bone composition. Minerals harden bone like the concrete poured into the infrastructure of a building, only bone is much more flexible.
- Many minerals compose bone including calcium, phosphorus, magnesium, and a host of trace minerals such as copper, zinc, manganese, boron, and silica. Many vitamins are needed for minerals to deposit into bone structure including vitamins A, C, D, E, K and EFAs (essential fatty acids).
Bone Remodeling
- Unlike buildings, bone is a living tissue and is constantly remodeling (that is, breaking down and building up). The body must break down the old bone to provide the building sites for new bone to rebuild.
- This is a normal and necessary process to maintain healthy bones.
- Remodeling requires a constant supply of bone-building material – proteins, vitamins, and minerals.
Hormonal Control of Bone Metabolism
1. Progesterone stimulates new bone growth
2. Testosterone stimulates new bone growth and promotes its strength and toughness.
3. DHEA stimulates bone growth.
4. Estrogen slows bone loss
Important Note: all the above hormones belong to the same family of hormones, steroid hormones, and each hormone can only properly play its role in bone health when in the correct balance with its other family members. Hormone replacement that uses high and / or imbalance amounts of any of the family members causes interference with their ability to function correctly.
5. Cortisol – excess cortisol in response to excess stress causes bone breakdown
Mechanical Stress and Bone Health
1. Bones grow and remodel largely due to the mechanical stresses, forces and demands made on them.
2. Gravity and exercise cause compression forces and muscle tendons pulling on the bones exert tension and torqueing forces.
3. This is the reason exercise, especially weight training and weight-bearing exercise strengthens bone.
4. Without adequate movement, weight bearing and resistance exercises, bone mass is lost
Osteoporosis
See: Perfect Bones: A Six-Point Plan to Promote Healthy Bones by Pamela Levin, R.N., The Nourishing Co
Definition
- Osteoporosis involves both the weakening of bone matrix and demineralization.
- Women typically reach their height of bone density at age 30.
- From age 30 on, many women will lose bone mass at the rate of about 1% per year.
Most Common Factors Leading to Osteoporosis
1. Poor childhood nutrition – fast food, processed food, food in package.
2. Poor nutrition in puberty when 60% of bone mass is being formed.
3. Poor nutrition in general, causing lack of ongoing building material for remodeling bone
4. Dieting – gaining and losing weight multiple times, as well as being too thin
5. Food disorders – bulimia, anorexia nervosa, sugar sensitivity / allergy
6. History of exercise level and type throughout lifetime:
a. Too little exercise does not stimulate healthy bone remodeling
b. Excessive exercise can cause excessive breakdown and sometimes hormonal deficiency in women
7. Smoking
8. Excessive alcohol consumption
9. Medications such as steroids, oral contraceptives, anticoagulants, diuretics, anticonvulsants, lithium, thyroxine
10. Hormonal imbalance
a. Estrogen Dominance
b. Low Progesterone
c. Low Testosterone
d. Low DHEA
e. High Cortisol – causes bone loss
f. Low Estrogen
11. Premenopause Syndrome – this state of estrogen dominance / progesterone deficiency accelerates premenopausal bone loss
12. Premature, surgical or chemical menopause, especially if the ovaries are removed
13. History of amenorrhea lasting more than a year
14. Intake of high doses of alpha tocopherol (“vitamin” E), synthetic vitamin A, or synthetic ascorbic acid (“vitamin C”) can cause bone loss
The Nurses’ Health Study – followed the dietary habits of 85,000 female nurses over the course of ten years. When evaluating the relationship between vitamin K (found in green leafy vegetables) and osteoporosis, researchers came to the conclusion that the nurses who ate the most vitamin K were about a third less likely to get a hip fracture. The significance of taking vitamin K was greater than taking a synthetic estrogen. Women who took a lot of vitamin D, but had low intakes of vitamin K, had doubled risk of hip fracture.
Understanding Bone Density Tests
- DEXA of Dual-Energy X-Ray Absorptiometry is considered the best method currently available to measure bone density.
- Reading a DEXA report is often as confusing as reading your phone bill.
- The test includes measurements of the hip, vertebrae (L4), and wrist, evaluating both trabecular (spongy) and cortical (rigid) bone.
- It is important to understand that DEXA measures bone density and not quality.
Reading the Test
Two scores
1. T-Score is a numerical comparison to the average bone density found at peak bone mass (a 30 year old).
2. Z-Score is a numerical comparison to the average bone density of an age-matched subject
- It is important to understand these are numerical representations of an average skeletal frame
- Women who are petite will often have lower scores, and this should be accounted for.
Scoring
Both scores are measured on a bell curve using standard deviations from normal
- Scores range between -3 and +3
- A negative score indicates lower bone density; a positive score indicates greater bone density.
- A 0 score indicates a bone density the same as the value you are being compared with
- Normal = a T-Score between -1 and +1
- Osteopenia = a T-Score between -2.5 and -1
- Osteoporosis = a T-Score below -2.5
- Significant risk for fracture = a Z-Score below -2
Problems with DEXA
It is important to remember that DEXA does not evaluate bone quality and bone health, and so it is not as accurate of a test as it is usually touted to be.
- “Ideally,” states J.C. Prior of the Division of Endocrinology and Metabolism at the University of British Columbia, the results of such tests “should be shown to correlate with the ashed mineral content of the bone, to parallel the tensile strength of bone, and predict the fracture frequency. None of the reported measurements can yet meet all these criteria.”1
- Indeed, according to J.E. Compston, Dept. of Medicine, University of Cambridge, some studies report that large increases in bone mas as seen in bone mineral density studies may actually be associated with a reduced bone strength and unchanged or increasing fracture rates. In fact, recent studies “indicate that fracture prevention is not necessarily associated with increase in bone density.”2
- “Truly healthy bones are not only dense, they are also flexible, supple and strong as a result of healthy micro-architecture. Bone density tests don’t measure these characteristics, which correlate more with fracture that density.”3
- Dr. John Lee recommends using the scores for the lumbar vertebrae (cortical bone) rather than the trabecular bone. Cortical bone “is relatively large and uniform, and the test results are generally more clinically accurate.”4
1J.C. Prior, “Progesterone as a Bone-Trophic Hormone” in Endocrine Reviews, Vol. 11, No. 2, May 1990, p6
2Bodmer, Kerry, “Editronate and Osteoporosis”, Women’s Health Newsletter, Vol.7, No.5, May 1998, p6
3Levin, Pamela, R.N., Perfect Bones: A Six Point Plan to Promote Healthy Bones, The Nourishing Company, (2000) p35
4Lee, John, M.D., Natural Progesterone, The multiple Roles of a Remarkable Hormone, BLL publishing, (1993) p84