The skeletal system comprises 206 bones, along with their associated cartilages, ligaments and joints. A healthy skeletal system consists of strong bones and stable, yet supple, joints. Osteoarthritis and osteoporosis are among the most common ailments of the skeletal system. These unrelated conditions, associated with deterioration of joints and weakening of bones, are at least partially preventable by observing certain do's and don'ts of exercise and nutrition.

Do This

Regular exercise is important for maintaining strong bones. When it comes to building and maintaining bone mass, choosing the right type of exercise is key. Weight-bearing exercises refer to those in which your muscles work against the force of gravity. This type of exercise stimulates an adaptive response in the body that leads to increased mineral density of the bones. Healthy bone mineral density makes bones less susceptible to fractures. The National Osteoporosis Foundation recommends exercises such as dancing, aerobics, hiking, jogging, jumping rope, stair climbing and tennis to help maintain strong bones.

Don't Do That

Contact sports and other activities that increase the risk of joint injuries increase the likelihood of arthritic degeneration of the joints in future years. A study published in September 2009 in the "Journal of Physical Activity and Health" reported that more than 40 percent of retired football players younger than age 60 reported arthritis compared to fewer than 12 percent of age-matched men who did not play football. The increased incidence of early-onset osteoarthritis in football players was attributed to injuries to ligaments and tendons during their playing years. Proper equipment and conditioning are important for injury prevention. Injuries to joints should be properly rehabilitated to minimize complications later in life.

Eat This

Consuming adequate amounts of calcium and vitamin D is critical to keep the skeletal system healthy. The authors of a study published in January 2011 in "Nutrition Research" suggest that inadequate vitamin D intake is common. They found low vitamin D levels in more than 40 percent of Americans. This prevalence suggests that it may be necessary for some people to take a vitamin D supplement to meet the minimum daily recommendation of at least 600 IU. Supplementation may also be necessary for some adults to meet the 1,200 mg recommended daily intake of calcium. People who avoid dairy due to allergies or sensitivities should consider supplementation. Other micronutrients needed for optimal bone health include magnesium, potassium and vitamins K and C. These are usually easy to obtain in a diet high in fruits and vegetables. Eating 5 servings of assorted fruits and vegetables daily usually provides adequate intake of these important nutrients.

Don't Eat -- or Drink -- That

While eating the right foods can help maintain healthy bones, certain dietary choices can contribute to bone mineral loss, potentially leading to osteoporosis and increased fracture risk. According to the National Osteoporosis Foundation, salty foods may weaken bones. Research presented at the 2013 meeting of the Endocrine Society appears to confirm the association between high salt intake and increased bone fragility. Avoiding processed or canned foods can help lower the amount of salt in the diet. Eating too much meat may also lead to a net loss of calcium in the bones. The National Osteoporosis Foundation also recommends moderation in consumption of alcohol, coffee, tea and soft drinks.