I'M BACK!!
Life got a little crazier than normal. Sorry for the delay. I'm in a new city, transitioning my "always gotta do something" attitude for "chill the fuck out, rachel", and taking the time to get back into writing. Man. I'm out of practice. Anyways, I wrote this piece for the last newsletter I did for EAC (waaaahhh), so, enjoy.
ANTIBIOTIC USE IN INFANCY AND OBESITY LATER IN LIFE
Probably a year ago at this point, a client of mine asked me if I had heard about a new study linking antibiotic use in infancy to increased adiposity (fat) later in life. Wayyyy back in my college days, we learned about a concept called the gut-brain axis, which is basically how the bacteria in our guts have their own universe, and it communicates back and forth with the central nervous system (brain and spinal cord) to control things like metabolism and mood. The interesting thing about this relationship is that the gut seems to have the larger impact on the brain - not vice versa (so who's really running the show here??!!??).
This brief conversation between him and I sparked a year of on-again, off-again research into the topic. I quickly learned that in the last 6 years or so, the research on the microbiota-gut-brain axis has been rapidly developing. I hope this is a somewhat comprehensible summary of my findings. They've also made it sound fancier, but with good reason. We used to lump microbiota (the community of microorganisms that share our body space) and the gut (the collection of actual digestive organs such as the stomach and small/large intestine) into one category, but new findings have shown the immense impact that the microbiota have on regulating gut and brain health. They basically keep us alive - we might as well properly recognize them.
THE ASSOCIATION BETWEEN ANTIBIOTIC USE IN INFANTS AND OBESITY LATER IN LIFE
The supposed initial article was discussing the correlation between antibiotics given to infants and the statistically significant rise in obesity of these babies later in life.
So what's going on? I found a study done by a research team at New York University's Langone Medical Center that describes it pretty simply. They hypothesized that gut microbiota regulated metabolism, and that changes to this population created lifelong disruptions in metabolism (even after the population was restored). But what was altering the gut microbiota? Their hypothesis: antibiotics given during the crucial time when our body is initially developing our microbiota, birth (some argue even prenatally) to 3 years of age. According to post-doctoral researcher Laura Cox, "Infancy is a time of growth and development where stem cells are dividing - they're choosing if they're going to become muscle or fat or bone. There have been other studies that show changes early in infancy can impact body composition later on."
Here's what they did to test this theory. (Animal model, not humans):
1. In one group, they gave the mothers antibiotics during the last week of pregnancy, and then continued the antibiotics after birth.
2. A second group of mice received a low dose of antibiotics after they were weaned from their mother, and then throughout their lives.
3. A third group was not given any antibiotics.
What did they find? The mice in the first two groups had significantly higher BMI's than the third group.
But how can you assume that the antibiotics weren't directly affecting metabolism? The scientists hypothesized that the microbiota were the culprits here, so they did one final experiment to make sure:
4. Lastly, they transferred the microbiota from an (antibiotic) exposed mouse to a germ free (no microbiota) mouse.
They also found that these mice became fatter.
This study was done back in 2012, and since then, more and more research and epidemiological studies have emerged backing the claim that antiobiotics given prenatally or within the first 1-3 years of life permanently alter the gut microbiota, specifically reducing the amount of Lactobacillus andBifidobacterium. When the gut microbiome is disrupted in this way, we see an altered metabolism and a heightened expression of the genes that promote fat adiposity (basically, your body wants to hold onto more calories and store them as fat). The questions that researchers are looking at now involve how or if these metabolic changes are permanent, and diet or other therapies to reduce the risk of temporary or permanent metabolic change.
<Quite honestly, if you think about it from a common sense standpoint (we're veering from science for a moment for a personal thought), it makes sense that this would be the body's overall response to antibiotics. Our bodies are created for survival. If we're signaling to our body from infancy that something is wrong, the body will enter survival mode, holding onto as much energy (calories) in the most efficient way: fat.
(Nutrition break: fat holds the most calories/gram, both in your food and on your body, at 9kcal/gram. Alcohol is second, at 7kcal/gram; both protein and carbohydrate hold 4kcal/gram).>
What can we do to prevent or treat this problem? There seems to be a growing movement to reduce the blanket antibiotic treatment (most infants are given antibiotics for preventative ear and upper respiratory tract infections), but, I'm not a doctor (and don't play one on tv), so my interpretation of these studies doesn't hold much weight. Look further into concepts such as fecal microbiota transplants, phage therapy, anti-quorum sensing, and anti-toxin production as alternative means for antibiotic treatments if you're curious.
I can, however, approach this from a diet prospective: probiotics are a great intervention. Probiotics are any live microorganism that helps us when given to us in an adequate amount. This differs from prebiotics, which are nondigestible substances that help the growth of the beneficial microorganism. (Basically, probiotics are the helpful bacteria, and prebiotics are food that help populate the helpful bacteria). Common probiotics include several
Lactobacillus and
Bifidobacterium species...aha! The same ones killed off by the antibiotics!
It's not clear if ingesting probiotics in adult life will help to regulate metabolism from getting these antiobiotic treatments as kids. But, it's not going to hurt you. Promoting gut health and maintaining the proper balance of bacteria in the gut is very rarely ever a bad thing. Gut health is related to immunity, mental health, and a host of other bodily processes.
(My crappy bibliography)....
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-Rachel Webb, RD
A real motherfucking dietitian.
