The health benefits of breastfeeding extend far past weaning. As researchers look at the various factors associated with different diseases, they often find that children and adults who were breastfed as infants are less likely to experience problems with chronic diseases. In some cases, even minimal amounts of breastfeeding may provide some protection against disease in later life, but usually the longer a baby is breastfed the greater the protective effect. Here are some of the ways that breastfeeding builds a lifetime of good health:

1. Breastfeeding prevents obesity. Even in infancy, breastfed babies as a group are leaner than their formula-fed peers. Studies have shown that children who are breastfed are less likely to be obese during adolescence, and that longer periods of breastfeeding greatly reduce the risk of being overweight in adulthood. Overweight children are more likely to become overweight adults. Since breastfed babies themselves control how much they eat (aided by the changes in fat levels during a feeding session), children who are breastfed learn to trust their bodies' signals about how much they need to eat and when. This builds healthy eating habits right from the start. Although parents might urge a formula-fed baby to finish up the last ounce or two of milk in the bottle, you can't do this to a breastfed baby. When she's done, she's done!

2. Better teeth. Breastfed babies have better jaw alignment and are less likely to need orthodontic work as they get older. A study of 10,000 children found that those who were breastfed for a year or more were 40 percent less likely to require orthodontic treatment. The sucking action used to breastfeed involves complex motions of the facial muscles and tongue. This improves the development of facial muscles and the shape of the palate. The better jaw alignment associated with breastfeeding can even mean less snoring and a lowered risk for a condition known as obstructive sleep apnea--the blockage of air flow during sleep, which can disturb sleep patterns and lead to other health problems.

3. Lowered risk of heart disease. All the evidence isn't in yet, but some researchers believe that breastfeeding during infancy may lower the risk of heart attacks and strokes in later life. This is due in part to the higher levels of cholesterol in human milk. Some heart researchers theorize that because of the cholesterol content of human milk, a breastfed baby's liver learns to metabolize cholesterol better than formula-fed infants. This leads to lower blood cholesterol levels as adults and thus a lower risk of heart disease. Though limited in number, some studies have shown that adults who were formula-fed as infants tend to have higher blood cholesterol and are more likely to have arterosclerotic plaques than those who were breastfed.

4. Lowered risk of juvenile diabetes. Babies who are breastfed are less likely to develop type 1 diabetes mellitus in childhood. Researchers have attributed this lowered risk of diabetes to the delayed introduction of cow milk in breastfed babies. In addition, researchers have shown a lower insulin release in breastfed infants compared to infants fed formula. This preventive effect is particularly important if you have a family history of diabetes.

5. Lowered risk of multiple sclerosis. Multiple sclerosis, a degenerative muscle disease that strikes adults, may be caused in part by myelin breakdown. However, multiple sclerosis is less common in countries where breastfeeding rates are high. Human milk's contribution to the myelin formation may help to prevent multiple sclerosis in later life.

6. Lowered risk of asthma and allergy. Studies have shown that breastfeeding lowers the chances of a child developing allergies and asthma symptoms. Breastmilk's immune components protect babies from allergens in the first months of life. Breastfeeding also delays the introduction of potentially allergenic foods, such as cow milk and soy protein, into the diet until the baby is older and the immune system is more mature.

7. Other diseases. Research suggests that breastfeeding may also play a role in preventing digestive diseases, such as ulcerative colitis and Crohn's disease, as well as childhood cancers. This makes sense: nourish an infant's body with the unique food designed for it by nature and that body will function in a healthier way, perhaps for the child's entire life.

Breastmilk's influence on health is probably more far-reaching than researchers have even dared to imagine, but studies of factors that affect the development of disease in adults seldom ask their research subjects how they were fed as infants (and many adults would have trouble giving accurate answers to these kinds of questions). New studies of what breastmilk contains suggest that this living biological fluid carries substances that are critical to the optimal development of many systems in the body. This early development may very well affect the progress of many diseases throughout life.