Mixed versus exclusive breastfeeding

Two major studies clearly show that there is a distinct difference between exclusive breastfeeding and the more common practise of mixed feeding: breastfeeding in combination with other foods. Mixed feeding is very common in African countries, and although solid food may be introduced as early as three months, breastfeeding will frequently continue alongside solid foods for up to two years after birth. In fact, the high rates of HIV transmission reported in the studies listed above were generally associated with mixed feeding.

The first study, conducted in South Africa, involved 551 women who were counselled on the risk of HIV transmission through breastfeeding, and offered formula at a subsidised price. After 15 months, transmission rates were 19% for formula-fed infants, 25% in exclusively breastfed infants, and 35% in mixed fed infants. It is suggested that mixed feeding may have exposed babies both to allergens, causing inflammation and damage to gut mucosal barriers, and to HIV, which in turn led to a higher infection rate.1

The second, larger trial was carried out in Zimbabwe as part of Zvitambo, a study designed to assess the impact of vitamin A supplementation on maternal and infant health. It enrolled over 14,100 mothers at the time of delivery, of whom 32% were HIV-positive at the time of enrollment. Mixed feeding resulted in a four-fold greater risk of HIV transmission after six months, although this fell to three-fold by 18 months after birth.2

These data present healthcare workers with a significant challenge, since mixed feeding is a very common practise in resource-limited nations. Only 26% of the women in the Durban study who chose to exclusively breastfeed their infants did so, while a separate study involving women in rural KwaZulu Natal found exclusive breastfeeding of very young infants to be uncommon, at a rate of 5%.3

References

  1. Coutsoudis A Method of feeding and transmission of HIV-1 from mothers to children by 15 months of age: prospective cohort study from Durban, South Africa. AIDS 15: 379-387, 2001
  2. Humphrey J et al. Safer breastfeeding for babies born to HIV-positive mothers: part of the answer to a dilemma. Twelfth Conference on Retroviruses and Opportunistic Infections, Boston, abstract 106, 2005
  3. Bland RM et al. Longitudinal infant feeding study: constraints to exclusive breast feeding. 13th International Conference on AIDS, Durban, abstract WeOrC497, 2000
This content was checked for accuracy at the time it was written. It may have been superseded by more recent developments. NAM recommends checking whether this is the most current information when making decisions that may affect your health.