Antibiotics can cause weight gain.
It’s not unusual for me to hear a story from a patient like this: “I don’t know what happened. I was doing really well with weight loss, but then suddenly I just ballooned.”
When I hear that I ask: “Did you take antibiotics sometime in the last 3-4 months?” Very often, the answer is: “Um… Oh right! Yes, I did.”
Weight gain from antibiotics is a clinical reality. The research is finally starting to catch up.
Evidence that antibiotics cause weight gain
In 2012, British researchers reported that children exposed to antibiotics early in life are more likely to become overweight later in life. Professor Martin Blaser from New York University Langone Medical Center has also done some fascinating studies. First, he demonstrated that mice exposed to antibiotics gained twice as much weight as untreated mice on the same diet. Professor Blaser then looked at humans. He monitored 92 subjects after one course for H pylori bacteria and found that their weight increased significantly. He also detected a dramatic increase in blood levels of the ‘hunger hormone‘ ghrelin. Made by stomach cells (and normally suppressed by H Pylori), ghrelin is a strong appetite stimulant and promoter of belly fat. In Professor Blaser’s study, antibiotics increased ghrelin by 6 times, and the hormone stayed high for 18 months. The satiety hormone leptin was also affected.
The ghrelin effect is just one mechanism for weight gain. Antibiotics also damage intestinal bacteria, and that translates into metabolic changes that we are only just starting to understand. Intestinal bacteria determine how many calories you absorb. They manufacture nutrients and reduce inflammation. Intestinal bacteria also have a direct influence on lipid metabolism and insulin sensitivity.
Antibiotics also damage mitochondria. That affects weight because mitochondria’s main job is to convert food into energy. If you have not yet heard of mitochondria, then get ready. You are going to hear a lot more about them very soon. Mitochondria are major players in health. They are tiny organelles that exist in each and every cell. Mitochondria burn calories. They also boost communication between synapses in the brain, manufacture heme (the main protein in hemoglobin), and slow aging (just to name a few of the many, many things that they do for us).
How many courses of antibiotics is too many?
I used to ask patients: “Do you take many antibiotics?”
I no longer ask that question, because the answer was usually: “not many”. By “not many”, most people meant one course of antibiotics per year. One course per year is apparently now perceived as normal and standard. Eek!
One course of antibiotics per year is too many. A better figure would be one or two courses in a lifetime. Antibiotics are amazing, life-saving drugs. I don’t like to imagine the world without them. But they are for life-threatening infections such as a kidney infection. They’re not for regular consumption.
Probiotics cannot fix the problem
Probiotics are not a solution.
I feel bad if natural medicine has somehow promoted the myth that “‘just take this probiotic after antibiotics” and all will be well. All will not be well. Probiotics relieve symptoms, promote the health of good bacteria, and prevent infection with bad bacteria like Clostridium.
But probiotics do not re-colonize your intestine. They cannot fix the permanent extinction of some species of intestinal bacteria that are caused by antibiotics. They cannot reverse the weight gain.
I’m not asking you to say no to antibiotics if you really need them. The time to make the decision is not when you’re dealing with a full-blown chest or sinus infection. The time to make the decision is now, as prevention, before you get to that point again. If you are prone to frequent infections, then you need an immune-boosting strategy such as zinc, vitamin D & dairy-free diet.
This is what I say to my patients: “I am prescribing an immune-boosting, antibiotic-avoiding strategy as part of your long-term weight loss plan.”