Until about 4 to 6 months, your baby’s digestive system has what is called an “open gut.” This means that there are spaces between the cells of the small intestine which allow proteins and pathogens to pass into the bloodstream. This allows beneficial antibodies from from breastmilk to pass into the bloodstream, but it also means that proteins and pathogens from solid food can also pass through. This can make your baby more susceptible to allergies and illnesses. The proteins and antibodies from breastmilk coats and fits into those openings, and gives your baby a passive immunity to prevent illnesses and allergic reactions before the gut closes. At age 6 months, your baby can start producing these antibodies on his or her own and the gut has closed by this time.

Giving your baby any breastmilk benefits your baby, but they receive the greatest immunity when they are exclusively breastfed. Breastmilk helps the development of good bacteria that protects the baby’s gut. By exclusively breastfeeding for 6 months (as compared to 4-6 months), you further decrease the risk of gastrointestinal infection and respiratory infection such as pneumonia for your baby.

Studies have shown that introducing your baby to solids too soon is linked to a higher risk of obesity and diabetes and an increase in body fat when they become adolescents and adults.

Exclusive breastfeeding for 6 months may reduce your baby’s risk of anemia. Giving your baby iron fortified food may reduce the efficiency of your baby’s iron absorption. A study showed that babies who were exclusively breastfed for 7 months had higher hemoglobin levels than babies who started solids earlier than 7 months.

Babies under 6 months don’t need the extra calories from solids. At this age, solids tend to replace breastmilk in your baby’s diet. This mean your baby will take in less breastmilk, which would lower your milk production. Babies who take in a lot of solids at this age will tend to wean prematurely.

There are also additional benefits to delaying solids to 6 months. Mothers are less likely to become pregnant when they are exclusively breastfeeding and they have more rapid postpartum weight loss. Your baby will also be more developmentally ready for solids, which will make introducing them much easier! If you have more questions about when and how to introduce solids, contact us at our Healthy Horizons Breastfeeding Centers or come to one of our Breastfeeding Support Groups.