Antibiotics and abnormal weight gain

The relationship between antibiotics and weight gain has long been known. Since the 1940s, tetracyclines have been associated with weight gain in human infants and in children. Significant weight gain has also been demonstrated in adults in the wake of antibiotic therapy (Rosenberg IH et al. 1974; Haight TH et al. 1995). Consequently, antibiotics have also been used in humans as adjunctive therapy for malnutrition (Trehan I et al. 2013; Smith MI et al. 2013). Cases of acquired obesity could also be associated with eradication therapy for Helicobacter pylori (Lane JA et al. (2011). In contrast, a weight-promoting effect could not be demonstrated for antifungal and antiviral drugs.

It is known that vancomycin leads to decreased gut microbial diversity in adults, with weight gain and acquired obesity (Million M et al 2013; Thuny F et al 2010). Cases of acquired obesity have also been associated with eradication therapy for Helicobacter pylori (Lane JA et al (2011).

In animal fattening, the use of antibiotics has been known for a long time. Used were: macrolides, tetracyclines and penicillins.

Long-term oral administration of doxycycline results in significant decreases in Bacteroidetes, Firmicutes, Lactobacillus, and total gut bacterial content. Thus, weight gain has been associated with a specifically altered profile of the gut bacterial microbiota, including a decrease in the Firmicutes/Bacteroidetes quotient and lower bacterial diversity (Angelakis E et al. 2014). M. smithii appears to play a dominant role in this. In an animal model, the degree and density of colonization with M. smithii was shown to correlate with the extent of weight gain (Angelakis E et al. 2014).

Antibiotics have been widely used in the past as adjunctive therapy for malnutrition (Trehan I et al. 2013; Smith MI et al. 2013). This approach has led many researchers to explore the effects of antibiotics administered in early infancy on childhood obesity. For example, vancomycin use has been associated with decreased gut microbial diversity, weight gain, and acquired obesity in adults (Million M et al. 2013; Thuny F et al. 2010).

Although changes in the gut microbiota resolve after short-term antibiotic therapy, long-term therapy can lead to profound changes.

1. Angelakis E et al. (2014) Abnormal weight gain and gut microbiota modifications are side effects of long-term doxycycline and hydroxychloroquine treatment. Antimicrob Agents Chemother 58:3342-3347.
2. Haight TH et al (1995) Effect of prolonged antibiotic administration on the weight of healthy young males. J Nutr 56:151-161
3. Lane JA et al (2011) Randomised clinical trial: Helicobacter pylori eradication is associated with a significantly increased body mass index in a placebo-controlled study. Aliment Pharmacol Ther 33:922-929.
4. Million M et al. (2013) Lactobacillus reuteri and Escherichia coli in the human gut microbiota may predict weight gain associated with vancomycin treatment. Nutr Diabetes 3:e87.
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6. Smith MI et al (2013) Gut microbiomes of Malawian twin pairs discordant for kwashiorkor. Science 339:548-554.
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