Nutrition
Consume a (pH enhancing) alkalinizing, acid neutralizing or non-acid generating diet. Preventing low-grade metabolic acidosis from developing by eating an alkalinizing diet can reduce and/or prevent the development of osteopenia and/or osteoporosis. A diet high in acid-generating (pH lowering) foods such as hard cheeses and animal protein can result in low-grade metabolic acidosis, reduced bone density and kidney stones; whereas, a diet high in acid neutralizing or alkalinizing nutrients such as fruits, vegetables, calcium, magnesium, and potassium can prevent low-grade metabolic acidosis, reduced bone density and kidney stones from developing.
A good gauge of a foods ability to generate acid or base (neutralizes acid) in the body is Potential Renal Acid Load (PRAL).
Calcium
One should include 1200 to 1500 mg of calcium daily either via dietary means or supplementation. A meta-analysis of randomized controlled trials concluded that "Evidence supports the use of calcium, or calcium in combination with vitamin D supplementation, in the preventive treatment of osteoporosis in people aged 50 years or older". Magnesium, potassium and zinc are also important for proper bone formation and maintenance. Note that it is important to use highly absorbable forms of these minerals, such as lactate.
Vitamin D
Increasing vitamin D intake has been shown to reduce fractures up to twenty-five percent in older people. New vitamin D intake recommendations by the National Osteoporosis Foundation, (July 2007) for adults up to age 50 are 400-800 IU daily and for those over 50, 800 - 1,000 IU daily.
Excess protein
High protein intake is known to encourage urinary calcium losses and has been shown to be associated with osteoporosis.
Exercise
Multiple studies have shown that aerobics, weight bearing, and resistance exercises may all maintain or increase bone mass density in women depending on the intensity of exercise, the individual's metabolic state, age, and level of routine activity.
Quitting tobacco smoking
Drinking alcohol in moderation