Prolonged breastfeeding is linked to the hypotensive effects of certain infant gut bacteria

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Tuesday, March 4, 2025

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Breastfeeding for at least six months can boost beneficial gut bacteria linked to better heart health years later.

What

An observational study funded by the National Institutes of Health (NIH) found that infants who had more diverse bacteria in their gut had lower blood pressure during childhood, and this protective association was stronger if they had been breastfed for at least six months. The results were published in the Journal of the American Heart Association.

For the research, the researchers examined data from 526 children enrolled in a prospective study in Denmark. They looked for links between infant gut bacteria, which can be influenced by nutrition and support various health functions, and the child's blood pressure. To assess this, they collected stool samples to analyze the bacteria in the infants' guts during their first week, month, and year of life. Three and six years later, they measured the children's blood pressure.

The researchers found that children with more diverse gut bacteria at one month of age had lower blood pressure six years later. They then assessed the influence of breastfeeding, which was measured in this study over durations of at least six months. They found that in children who were breastfed for at least six months, the blood pressure-lowering effect of greater gut bacteria diversity was even stronger. Specifically, those who had greater gut bacteria diversity throughout the first month of life had systolic blood pressure that was about 2 mm Hg lower six years later if they had been breastfed for at least six months.

Researchers believe several reasons may explain these associations. Some gut bacteria have developed specialized biological machinery that allows them to convert the otherwise indigestible carbohydrates in breast milk into calories and substances that can be used by the body. Specific species of Bifidobacterium of which B. infantis, are superstars when it comes to breaking down these carbohydrates and turning them into short-chain fatty acids that can influence blood pressure and support cardiovascular health.

In infants who are not breastfed, bacteria that lack carbohydrates from breast milk to feed on may instead break down the carbohydrates lining the intestines. This could lead to a condition called leaky gut, in which bacteria and fats could enter the bloodstream. A leaky gut has been linked to inflammation and increased blood pressure in adults.

Additionally, researchers discovered that certain types of bacteria, including H. pylori, were present in some infants and that these bacteria were linked to increased blood pressure years later. H. pylori, which can be passed from mother to child, can create persistent levels of low-grade inflammation and may influence a “leaky gut.”

To make the study participants as comparable as possible, the researchers took into account the mother's medical history, her diet during pregnancy, pregnancy complications, when and how a child was born, and the duration of breastfeeding.

Approximately 4 to 7 percent of children worldwide suffer from high blood pressure, which can begin when the fetus is developing in the womb. These rates have doubled since 2020, so researchers are studying factors that can offset these risks and improve cardiovascular health.

The study was funded by a grant from the National Heart, Lung, and Blood Institute (NHLBI) K01HL141589.

Who

Charlotte Pratt, Ph.D., RD, Acting Chief, Clinical Applications and Prevention Branch, NHLBI

Study

About the National Institutes of Health (NIH): NIH, the nation's medical research agency, comprises 27 institutes and centers and is part of the U.S. Department of Health and Human Services. NIH is the primary federal agency that conducts and supports basic, clinical, and translational medical research, and studies the causes, treatments, and cures for common and rare diseases. For more information about NIH and its programs, visit www.nih.gov.

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