By Dr. Mercola
You may be aware, and possibly have experienced firsthand, that antibiotics can cause diarrhea.
This is because antibiotics, by design, disrupt the balance of good and bad bacteria in your gastrointestinal tract, often killing off both beneficial and harmful microorganisms without distinction.
It is through this same mechanism that antibiotics may also be causing you to pack on extra pounds.
In fact, Dr. Martin Blaser, a professor of microbiology at New York University Langone Medical Center, suggests that antibiotics may permanently alter your gut bacteria and interfere with important hunger hormones secreted by your stomach, leading to increased appetite and body mass index (BMI).
Antibiotics Lead to Increases in Body Fat and Hunger Hormones
Research by Dr. Blaser has shown that 18 months after antibiotics are used to eradicate H. pylori bacteria, there is a:
- 6-fold increase in the release of ghrelin (the "hunger hormone") after a meal
- 20 percent increase in leptin levels (leptin is a hormone produced by fat tissue)
- 5 percent increase in BMI
Levels of ghrelin should ordinarily fall after a meal to signal your brain that you're full and ready to stop eating; an increase would therefore essentially tell your brain to continue eating, leading to weight gain. Further, the increase in leptin levels is concerning because overexposure to high levels of the hormone can lead to leptin resistance, which means your body is unable to properly hear leptin's signals.
The way your body stores fat is a highly regulated process that is controlled, primarily, by leptin. If you gain excess weight, the additional fat produces extra leptin that should alert your brain that your body is storing too much fat and needs to burn off the excess.
To do this, signals are sent to your brain to stop being hungry and to stop eating. When you become leptin-resistant, your body can no longer hear these messages -- so it remains hungry and stores more fat.
Interestingly, you can easily become leptin resistant by eating the typical American diet full of sugar (particularly fructose), refined grains and processed foods … which, like antibiotics, will upset the balance of bacteria in your gut.
Farmers Use Antibiotics to Fatten Up Livestock Quickly
About 70 percent of all the antibiotics produced are used in agriculture -- not necessarily to fight disease, but rather to promote weight gain.
As stated by the Ontario Ministry of Agriculture, Food and Rural Affairs:
"Continuous, low-dose administration of an antibiotic can increase the rate and efficiency of weight gain in healthy livestock. The presence of antibiotics likely changes the composition of the gut flora to favor growth. Debate is ongoing as to how gut flora are changed; change may simply be a reduction in numbers, a change in species composition or a combination of the two.
… Some antibiotics may also enhance feed consumption and growth by stimulating metabolic processes within the animal."
Unfortunately, this practice is also contributing to the alarming spread of antibiotic-resistant disease. As it pertains to your weight, there's ample reason to believe that this same phenomenon occurs in humans as well, figuratively turning Americans into fatted calves.
Your Gut Bacteria and Your Waistline Go Hand-in-Hand
Research by Dr. Blaser, for instance, found that mice fed antibiotics (in dosages similar to those given to children for throat or ear infections) had significant increases in body fat despite their diets remaining unchanged.
Multiple studies have actually shown that obese people have different intestinal bacteria than slim people, and that altering the microbial balance in your gut can influence your weight. Here are six such studies:
- When rats were given lactic acid bacteria while in utero through adulthood, they put on significantly less weight than other rats eating the same high-calorie diet. They also had lower levels of minor inflammation, which has been associated with obesity.
- Babies with high numbers of Bifidobacteria and low numbers of Staphylococcus aureus -- which may cause low-grade inflammation in your body, contributing to obesity -- appeared to be protected from excess weight gain. This may be one reason why breast-fed babies have a lower risk of obesity, as Bifidobacteria flourish in the guts of breast-fed babies.
- Two studies found that obese individuals had about 20 percent more of a family of bacteria known as Firmicutes, and almost 90 percent less of a bacteria called Bacteroidetes than lean people. Firmicutes help your body to extract calories from complex sugars and deposit those calories in fat. When these microbes were transplanted into normal-weight mice, those mice started to gain twice as much fat.
- Obese people were able to reduce their abdominal fat by nearly 5 percent, and their subcutaneous fat by over 3 percent, just be drinking a probiotic-rich fermented milk beverage for 12 weeks.
- Probiotics (good bacteria) have been found to benefit metabolic syndrome, which often goes hand-in-hand with obesity.
- Probiotics may also be beneficial in helping women lose weight after childbirth when taken from the first trimester through breastfeeding.
Healthy Gut Bacteria Cannot Coexist With Antibiotics
Antibiotics can save your life if you develop a serious bacterial infection, but it's important that you resist the urge to ask your physician for a prescription for every ear, nose, or throat infection you come down with. Likewise for a cold or the flu. Antibiotics are useless against viral infections like these, and when used for this purpose will only harm your health by wiping out the good bacteria in your gut.
Antibiotic use has become so routine in the United States that one round of the drugs may seem like no big deal, but remember that using them drastically alters the makeup of bacteria in your gut, which will need to be rebuilt in order for you to stay in good health. Whenever you use an antibiotic, you're also increasing your susceptibility to developing infections with resistance to that antibiotic -- and you can become the carrier of this resistant bug and even spread it to others.
Ultimately the problem of antibiotic-overuse needs to be stemmed through public policy on a nationwide level, especially in the agricultural community, but I urge you to also take personal responsibility and evaluate your own use of antibiotics, and avoid taking them -- or giving them to your children -- unless absolutely necessary.
Remember that the foods you eat are also a major source of exposure to antibiotics, so to protect your gut bacteria you should buy primarily antibiotic-free, organically raised meat and produce. Keep in mind that conventionally farmed food is often grown in fertilizer derived from factory-farmed animal waste and human sewage, which may be a source of contamination with antibiotic-resistant bacteria.
The Recipe for Healthy Gut Bacteria
Your gut bacteria are vulnerable to your lifestyle. If you eat a lot of processed foods, for instance, your gut bacteria are going to be compromised because processed foods in general will destroy healthy microflora and feed bad bacteria and yeast.
In addition to antibiotics, your gut bacteria are also very sensitive to:
- Chlorinated water
- Antibacterial soap
- Agricultural chemicals
Because virtually all of us are exposed to these at least occasionally, ensuring your gut bacteria remain balanced should be considered an ongoing process, and consuming fermented foods is one of the best ways to do this.
One of the reasons why fermented foods are so beneficial is because they contain lactic acid bacteria -- a type of beneficial gut bacteria that research shows can help you stay slim.
I have long stated that it's generally a wise choice to "reseed" your body with good bacteria from time to time by taking a high-quality probiotic supplement or eating non-pasteurized, traditionally fermented foods such as:
- Lassi (an Indian yoghurt drink, traditionally enjoyed before dinner)
- Fermented organic grass-fed raw milk, such as kefir
- Various pickled fermentations of cabbage, turnips, eggplant, cucumbers, onions, squash and carrots
- Natto (fermented soy)
If you do not eat fermented foods on a regular basis, a high-quality probiotic supplement can be incredibly useful to help maintain healthy gut bacteria when you stray from your healthy diet and consume excess grains or sugar, or if you have to take antibiotics.
Also please remember that it is vital to eliminate ALL sugars. They will sabotage any beneficial effects of the fermented foods, as they will act as nutrients for the pathogenic yeast, fungi and bacteria that are in your gut.