I am in my 40's. What do I need to know about bone density?

Bone density is of concern to women as they reach mid-life because women have a higher rate of osteoporosis and subsequent fractures. Women are at greater risk because: we loose bone mass after menopause, we start out with smaller bones, and we live longer.

Throughout life, the bone re-models itself. That essentially means that it re-develops and renews itself. This renewal is comprised of two processes: the breakdown of the old bone and the creation of the new. Mineralization (with calcium) is the final stage which makes the new structure solidify into hard bone.

At about age 35, you have what is called Peak Bone Mass--your bones are as dense and strong as they will be. Before that time, the renewal phase was greater than the breakdown. Starting in the later thirties and continuing into the forties and beyond, this ratio reverses, so that about 1% of bone mass is lost each year.

The risk of fractures that ultimately come from bone loss and osteoporosis are only significant for about 5% of women in their forties. That is to say only 5% of women in their forties are below what is called the "fracture threshold", not that 5% are actually having fractures. The Fracture Threshold is the level of bone density at which fractures become a serious risk.

While genetics and what you did in your earlier years are prominent factors in determining your bone density, lifestyle today still plays a major role. Here's some things you can do to minimize bone loss:

A woman in her forties needs about 1000-1500mg of calcium a day. The lower amounts are for pre-menopausal, non-pregnant forties women. The higher amounts are needed in menopausal forties women.

Dairy foods are most women's main source of calcium. A cup of milk or yogurt has about 300 mg. Despite the popular "milk mustache" and "got milk" campaigns, milk should not be the sole source or even the main source of calcium for many women. It has a lot of fat and calories associated with the it. In the forties, it is not always the best option, as this is a time when metabolism is slowing down. In addition, women of all ages are lactose intolerant, meaning they have trouble digesting milk. Sardines, spinach, and green vegetables are also good sources of calcium that are low in fat, and high in fiber. Supplements can always be considered.

Vitamin D is essential to calcium absorption. Good sources of vitamin D are egg yolk, liver, and fish. It can be gotten through supplements, taken alone or the ones that are frequently added to milk and cereals. Sun exposure causes biochemical reactions in the body that increase Vitamin D levels. It only takes fifteen minutes at mid-day, so don't go out and bake and end up with skin problems.

Weight-bearing exercise. Running or jogging, walking, aerobics, and dancing are just a few types of activity that fall under this umbrella. In the forties, be aware of your own limits and injury history. Lastly, limiting alcohol, smoking and caffeine will also help keep bones stronger, longer.