When taken too often, antibiotics are harmful to gut health. Medical evidence proving such damaging effects has grown significantly over the past year.

The main hazards linked to taking too many rounds of antibiotics have centered on a growing vulnerability to Clostridium difficile (C. diff) infections and obesity in adults.

Unfortunately, the harm antibiotics do to human health may start much earlier, during the early stages of childhood development—even before your baby is born—and may last for a lifetime, according to a pair of recent studies.

Reprogramming your baby’s gut health with antibiotics

Researchers at NYU’s Langone Medical Center studied the effect low doses of penicillin given over a lifetime would have on the health of mice in a study published in the medical journal Cell.

The big picture conclusion: Starting in the last week of pregnancy or during nursing, mice given low doses of penicillin were more vulnerable to metabolic abnormalities including obesity than animals exposed to antibiotics later in their lives.

In the main experiment, researchers compared the effect of penicillin on three groups of rodents: Two groups received penicillin—one before birth and the other later after weaning—then for the remainder of their short lives, while a third control group was given no antibiotics at all.

Both groups of mice that were fed penicillin had higher amounts of fat on their little bodies than the control group, but the womb group was the fattest, providing solid proof that mice were “more metabolically vulnerable if they get antibiotics earlier in life,” says Dr. Laura Cox, lead author of the study.

Not only did penicillin-treated mice carry twice as much fat compared those fed only high-fat food, but their bodies also showed signs of metabolic disorders.

Do antibiotics lessen the amount of gut bacteria? Not necessarily…

Scientists took another important step by transferring gut bacteria from penicillin-treated mice and those not given the antibiotic to antibiotic- and germ-free mice shortly after the time they would be weaned (three weeks old).

Mice given gut bacteria from donors treated with antibiotics were fatter than those treated with antibiotic-free gut bacteria.

Another interesting discovery made by NYC researchers during their study may have overturned a long-standing belief that antibiotics (at least penicillin) reduces the amount of gut bacteria contained in the body.

As a whole, gut bacteria didn’t decrease, but four very important strains did: Allobaculum, Candidatus, Arthromitus, member of the Rikenellaceae family and the very popular Lactobacillus (one of the key bacteria ingredients in EndoMune Advanced Probiotic).

These results reaffirm the work conducted by one of the most popular researchers in the field of gut health research, Dr. Martin Blaser, director of the NYU Human Microbiome Program and author of the book, Missing Microbes: How the Overuse of Antibiotics is Fueling Our Modern Plagues.

More evidence broad-spectrum antibiotics may trigger obesity

A more recent study appearing in JAMA Pediatrics gets to the heart of the problem: Health problems occur when exposing babies under age 2 and up to age 5 to broad-spectrum antibiotics.

Using electronic records spanning 2001-13 from a network of primary health clinics, scientists tracked the health of more than 64,000 children from birth to age 5. The numbers speak volumes:

• Nearly 70 percent of all children were exposed to antibiotics more than twice on average before they reached age 2.

• Young children who were exposed to all antibiotics or broad-spectrum antibiotics four or more times had a greater risk of obesity.

• The prevalence of obesity or being overweight increased over time from 23 percent at age 2 to 33 percent at age 4.

One additional factoid from the study that’s worth noting: No link was found between obesity and prescribing children narrow-spectrum antibiotics, medicines that treat a more select group of bacterial types, according to the Alliance for the Prudent Use of Antibiotics (APUA).

However, broad-spectrum antibiotics can handle a greater number of bacterial types and are often prescribed to treat a wider variety of infectious diseases or when the source of the infection is unknown, according to APUA. Varieties of broad-spectrum antibiotics include some synthetic penicillins, quinolones and aminoglycosides.

Because infants are so very vulnerable to antibiotics, especially soon after they’re born, it’s important for moms to work with their family pediatricians to ensure their babies get the healthy start they need to avoid metabolic problems that could lead to lifelong ailments like obesity.

The good news: A multi-species probiotic like EndoMune Advanced Junior can give your baby’s health a much-needed boost by protecting the diversity of beneficial bacteria in their gut and strengthening their tiny but growing immune systems.