March 1, 2004 -- Children who were breastfed as infants may have healthier hearts than their bottle-fed counterparts, and the benefits may last well into adulthood researchers say.
Researchers say breastfeeding has been linked to a number of health benefits in childhood, but there may also be some benefits that extend into adulthood.
"There is some weak evidence that there is a small lowering of blood pressure in adulthood [among children who were breastfed], but the evidence is inconsistent," says researcher Richard Martin, MSc, MFPH, of the University of Briston, U.K., in a news release. "No one has investigated in a prospective study whether the association changes with age."
Breastfeeding May Protect Children's Hearts
In the study, published in today's rapid access issue of Circulation: Journal of the American Heart Association, researchers tracked the effects of breastfeeding on 4,763 children in the U.K. who were born in 1991 and 1992 and were then examined when they were about 7 1/2 years old.
Researchers found that children who were breastfed for any length of time had slightly lower blood pressure than those who were exclusively bottle-fed using baby formula. After adjusting for other factors that might affect blood pressure, such as birth weight and mother's education, the study showed that breast-fed children had blood pressure readings that averaged 0.8 mm Hg lower for systolic pressure (the top number) and 0.6 mm Hg lower for diastolic pressure (the bottom number).
"Even this small reduction may have important population-health implications," says Martin. "A 1% reduction in population systolic blood pressure levels is associated with about a 1.5% reduction in all-cause mortality, equivalent to a lessening in premature death of about 8,000 to 20,000 deaths per year in the United States and the United Kingdom, respectively."
In addition, the study showed that the blood pressure-lowering effects of breastfeeding increased with the duration that the infant was breastfed. On average, every three months of breastfeeding was associated with a 0.2 mm Hg reduction in systolic blood pressure.
Researchers say differences in the nutrient content of breast milk and formula may at least partially explain the blood pressure-lowering effects found. Children who are breastfed tend to consume less sodium, which is associated with raising blood pressure.
In addition, they say formula feeding is more likely to lead to overfeeding and overweight babies -- two factors that are also known to raise blood pressure.