And the longer the period of breastfeeding, the lower the blood pressure reading, shows the research published in Archives of Disease in Childhood.
The research team assessed the impact of breastfeeding on elements of the metabolic syndrome in over 2000 randomly chosen children from Denmark and Estonia, aged between 9 and 15.
The metabolic syndrome refers to a combination of conditions that raise a person's risk of coronary artery disease. These include high blood pressure, diabetes, high insulin levels, high triglyceride levels, and low HDL cholesterol levels.
Breastfeeding did not have an impact on every element of the metabolic syndrome. But children who had been exclusively breastfed had lower systolic blood pressure than those who had not, said the researchers.
And the longer a child had been exclusively breastfed, the lower was his or her systolic blood pressure.
The effect may increase as a child ages, because the results showed that the greatest impact was on the older children, although the figures were not statistically significant.