Understanding Bone Strength

Bone is a mineralized living tissue which is constantly being broken down and rebuilt or remodeled. In fact, the body grows the equivalent of an entirely new skeleton every 7 years. There are two main types of cells that are crucial to bone remodeling – osteoblasts, and osteoclasts. The job of osteoblasts is to build new bone, and the job of osteoclasts is to break down bone. In healthy bone tissue, osteoblasts and osteoclasts work in balance with one another, routinely breaking down bone when needed by the body, and then rebuilding bone tissue to replace and strengthen the bone. When bone remodeling begins to favor break down of bone by osteoclasts over bone formation by osteoblasts, bone strength may be affected.

Everyone is at risk. It is a common misconception that only older women need to worry about bone loss. In fact, both men and women will begin to lose 0.5-1% of their bone density or degree of bone mineralization per year starting around age 30. In women, the rate of loss will spike to 2-3% per year for the first 3-15 years following menopause, which means that over the course of a lifetime, women will likely lose a higher percentage of their bone mass than men, but men are in no way protected from the potentially dangerous consequences of age-related bone loss.

So how do we meet our calcium needs? Studies have shown that individuals who obtain their calcium mainly from food have healthier bones than those who rely on calcium supplements to meet their needs. Why the difference? Most people’s calcium supplements contain an inorganic form of calcium called calcium carbonate, also known as limestone. Yes, that’s right, rocks. Not surprisingly, this very dense molecule is notoriously difficult for stomach acid to penetrate and subsequently enable the release of elemental calcium for absorption into the body. Similar to most nutrients, the body can utilize calcium more effectively when it is paired with co-factors naturally found in food such as magnesium and trace minerals.

Calcium is not the only nutrient you'll need to prevent bone loss. Bone is a living tissue made up of more than just calcium, and calcium does not function in isolation. Other vitamins and minerals play a major role in determining whether the calcium you ingest will actually be absorbed and properly utilized by the bones. The “calcium paradox” holds that without adequate vitamin K, calcium will not be deposited in the bones where it is required for maintaining bone strength, but rather in the arteries where it can severely compromise cardiovascular health. Another vitamin critical for calcium absorption and utilization is vitamin D. Individuals who are deficient in vitamin D absorb about one half the amount of calcium as individuals who maintain sufficient vitamin D levels. Magnesium and trace minerals like silica, vanadium, boron, and strontium have also been shown to be essential for the normal growth and development of skeletons in humans and animals, and should be included in a bone health nutritional program.

Vitamin K1, the form of vitamin K derived from plant foods, is poorly absorbed by the body. Vitamin K2 is the preferred form of Vitamin K for supporting bone health, protecting against osteoporosis, pathological calcification and cardiovascular blockages by depositing calcium in the bones and blood, and preventing calcium from being deposited in the vessels which case calcification (a risk for coronary artery disease). A form of vitamin K2 derived from the traditional Asian soy food natto has been clinically shown to promote bone health, as it contains a bacteria that can convert vitamin K1 into vitamin K2. A single daily dose of 45mcg of it can ensure delivery of K2 (MK-7) to all of the body's tissues 24 hours a day.

1. Organ meats such as liver, eggs, cheeses, fermented cheeses and curd are also good sources of vitamin K2.

1. Vegetables that are high in vitamin K, such as green peas, can also be a good source of vitamin K2. For example, green peas are a good source of vitamin K, some of which is converted into K2 by the body. Other excellent sources of vitamin K include spinach, Swiss chard, Brussels sprouts, broccoli, kale, asparagus, mustard greens, carrots and green beans.
2. For detailed information regarding trace minerals and vitamins, click on archived May 2009 blogs.
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