Healthy bones are important for a number of reasons: They provide a framework for your body, serve as levers for movement and store critical nutrients. Blood cells are manufactured in the marrow of the bones. Bones have both tensile strength, which allows some pliability to resist breakage, as well as compressible strength, which makes them strong and hard. Bone density is a measure of the strength and thickness of bone tissue. To understand bone density and what influences it, you need to understand the nature of bone.
Bone Structure and Function
Though many don't think of it as such, bone is living tissue, and is subject to the same influences as other body systems. The outer layer of bone is hard, but the inner core is referred to as "spongy," a lattice-like structure that contains bone marrow. Bone serves an important storage site for minerals such as calcium and phosphorus, which can be drawn upon if the body becomes depleted. In the red bone marrow of large bones, red and white blood cells and platelets are manufactured. Poor nutrition and inadequate vitamin D absorption can compromise the integrity of bones.
Bone Growth and Development
In infancy, bone is cartilaginous in nature. That is, it is made up of connective tissue that is pliable and resistant to breakage. At the onset of puberty, the bodies of both males and females begin the ossification, or hardening, process, which will continue until the individual reaches their full adult height. The hormone estrogen plays an important role in this developmental phase in both sexes. After ossification, bone tissue is continually being renewed and replaced by the body. The ability of the body to produce new, healthy bone tissue is influenced by nutrition, exposure to sunlight, hormones and physical exercise.
Nutrition and Bone Health
Although calcium is touted as a bone-strengthening supplement, calcium alone is not enough to stimulate strong bone development. Vitamins A and C are also crucial, as is vitamin D, which helps bone to absorb calcium and integrate it into its structure. Vitamin D deficiency, also know as rickets, can compromise bone strength, especially when experienced during adolescence. Your body naturally manufactures vitamin D from sunlight, but because children and adults spend increasingly less time outdoors, and because they slather on sunscreen when they are outside, vitamin D deficiency has become common in Western cultures.
Things That Weaken Bones
Even well-nourished individuals who get adequate Vitamin D can be subject to loss of bone density. Carbonated soft drinks, both diet and regular, take a toll on bone tissue because the phosphates they contain leach calcium from the bones. Smoking and excessive alcohol consumption also weaken bones. Inactivity and a sedentary lifestyle do not promote strong bones for the same reasons inactivity does not promote strong muscles.
Ways to Strengthen Bones
To ensure strong, healthy bone development, pay attention to nutrition. Are you getting enough fruits, vegetables and other nutrient-dense food to satisfy your body's needs each day? Spend several minutes outdoors each day to allow your body to absorb the sunlight necessary for vitamin D production. The more skin you expose, the more vitamin D you will absorb. Darker-skinned people need longer exposure than fair-skinned individuals. Engage at least two or three times per week in a total body weight-bearing exercise routine. Weight-bearing exercise is crucial to stimulating increased bone density.
