Are Probiotics Good for Your Health?

Cynthia Bailey, MD|December 7, 2012

probiotics and stomach bacteria

Should you be cultivating your good germs the same way a farmer cultivates crops?

Can antibiotics be bad for you because they kill off too many germs?  

Science is at the dawn of a new era and the answers to these questions might surprise you!   Your body is full of “good germs” that may help you avoid asthma, fight sinus infections, boost your mood, and even control your weight. You need to know how to care for these good germs so they can help keep you healthy.

As a baby, you were born “germ free.” By adulthood, you’ve got 3 lbs of germs, called your microbiome, living in and on your body – and they’re either helping or hurting you! Your human body is home to a community of bacteria and yeast that's upwards of 10,000 different types of good germs. These cells outnumber the actual cells of your body by 10 to 1.

Until recently, doctors and scientists have believed that altering your microbiome with antibiotics was inconsequential to your health. Evidence is mounting, however, that killing off your microbiome with antibiotics may be harmful to your health. This means that our modern love affair with antibiotics may be coming to an end.

In this post, I want to share with you a fascinating article titled "Germs Are Us" that was published in the October 22, 2012 issue of The New Yorker magazine.  Yes, The New Yorker – not my usual scientific journal. Nevertheless, the article is an excellent overview of new scientific research into the human microbiome, and the information is important to your health. A long-time patient of mine brought me the article. She knew that I’d be interested, because I’m a big fan of probiotics. I know that every antibiotic prescription I write for a patient alters their microbiome. I counsel my patients on rebalancing their "flora and fauna" with probiotics after antibiotics. Now it seems that the impact of antibiotics on human health may be even bigger than I thought.

The author interviewed the leading scientists studying the human microbiome. What they’re learning will undoubtedly surprise you. First, you need to know that this is serious science, not wacko hucksters trying to sell you probiotic personal care products. The heavy hitters in research are putting significant research funds and focus towards this subject: the NIH, the European Commission, and China are all avidly studying it. So far, what we know is that the germs of your microbiome colonize every surface of your body. Most are in your gut, but you’ve got them in your nose, sinuses, ear canals, on your skin, etc. The variety of microorganisms, which are mostly bacterial, are huge. We also know that each person has their own unique set of "good" microbiome germs. At this point, most of the exciting research is focused on the germs living in the human gut. This subset of your microbiome is called your enterotype. Eventually doctors will be able to test and define your enterotype much like they can your blood type. They’ll be able to know which germs are good for your unique body, and which are actually bad for you. I imagine we’ll have the same sort of typing for your skin too, and the other colonized parts of your body as well.

So, what are the first exciting discoveries about your good (symbiotic) germs?

#1.  Good Bacteria May Help You Fight Obesity 

The most mind-blowing discovery for me is that some bacteria might help make you skinny. Yes, your gut germs may play a role in what you digest after every meal, including calories!  It is believed that at the beginning of the 20th century almost every person had a germ called H. pylori in their stomach. In developing countries, people still commonly have this stomach germ; but, now, only 1/5th of U.S. kids have it, probably because the germ is killed by antibiotics. In our country, kids receive, on average, 10-20 courses of antibiotics by the time they grow up; these antibiotics may kill off H.pylori, and the consequences may explain part of the obesity epidemic! H. pylori is a bacterium that, up until recently, we thought was always bad. It’s associated with stomach ulcers and some other health problems.  But now, it looks like some types of H. pylori might be good for your health because they play a role in managing your weight and more.

H. pylori appears to be important for the formation of a hormone that tells you when you’re full, so that you stop eating. It may be that “a whole generation” of kids today are growing up without this bacteria regulating their levels of this hormone, meaning the message to stop eating doesn’t reach their brain. Adding intrigue to this new observation, mice absorb more calories from their food and gain weight when they are given the same sort of antibiotic dosages use to treat a child’s ear infection. Yep, they get fat; no change in diet, just antibiotics, and it’s fat mice.  Apparently, the antibiotics kill the germs in the gut, which leads mice to “absorb more calories from the same amount of food and rapidly become obese.”

Taking the weight/antibiotic/gut bacteria connection one step further, the meat industry uses 3/4 of all antibiotics consumed in the US. Scientists speculate that the antibiotics fed to these animals (poultry, cows, and pigs) are probably bringing the animals to market weight fast because of the impact they have on gut bacteria and weight gain, not because the drugs are preventing or treating diseases to keep animals healthy.

#2.  Good Bacteria May Impact Your Risk of Asthma and Allergies 

It looks like H. pylori may protect against asthma and allergies too. Scientific researchers have correlated that the people with asthma are far more likely to NOT have H. pylori in their gut. In the laboratory, they also found that mice without H. pylori reacted more severely to dust mites and other allergens compared with mice with H. pylori.

#3.  Good Bacteria May Help You Prevent Sinus Infections

Researchers have found that a bacterium called Lactobacillus sakei may actually help prevent sinusitis. People who have this germ in their sinuses seem to be protected from sinus infections. The germ is killed by antibiotics.

#4.  Bad Bacteria May Increase Your Risk of Dental Cavities

Cavities may now be an infectious disease! A germ called Streptococcus mutans, which lives in the mouth, releases acid in the presence of sugar. This acid corrodes teeth. The next big question is, could cavities be eradicated by a mouthwash that kills S. mutans? Maybe. Can probiotic-rich foods provide good bacteria to crowd out the bad ones?  Interesting question.   I believe that it's the beginning of a new era in medicine, and it's complicated! 

The scientific studies are still evolving. So while we’re waiting for more information to emerge, what can you do to boost your body's good germs?

We don’t know for sure. Not every probiotic bacterium is good for every person. For example, Lactobacillus GC appears to reduce the risk of eczema in babies, but for people who have Crohn’s (a severe intestinal disease) it can worsen their disease. We also know that your bacterial population is dynamic, changing over the course of your life. The two questions I think we can answer right now are:

  1. Is there some stewardship you can/should be doing to "cultivate and nurture" your microbiome to maximize the presence of your good germs while discouraging the bad ones? 
  2. Should you start using every product labeled to contain “probiotics”?

The answers are common sense, but none-the-less important. I break them down into 2 steps, and they are my opinion only.

Step 1. Avoid antibiotics unless they are clearly needed to treat an infection. I’d also recommend avoiding them in the dairy and meat products you consume. To do this you need to eat organic alternatives only. Organic meat and dairy is more expensive. You can keep this from breaking the budget bank by eating half as much as you normally would, and increasing the less expensive alternative foods such as veggies, whole grains, and legumes. There are other great reasons to tweak your diet in this direction too. (To read more, click here for my post The Best Diet For Healthy Skin in 2012.)

Step 2. Include probiotic-rich foods in your diet. (Ask your doctor if you have a complex disease such as Crohn’s, an autoimmune disease, are immunosuppressed, or think this might not be safe for you to do.) Probiotic organisms are the fermenters used to preserve foods by our ancestors. They were eaten regularly because they were an essential part of food storage in a time when people did not have refrigerators, preservatives, and sterilization techniques. It means that the human body learned to live symbiotically with these organisms over thousands of years. Naturally probiotic rich foods are fermented foods that have not been cooked, because cooking kills the good germs. I prefer fermented foods over supplements labeled as “probiotics”, or foods with “probiotics” added as “fairy dusting” sales gimmick. I analogize probiotic cultures to a gold fish – you only want them if they are alive, and you want to see proof.  With a gold fish, you can tell if it’s alive because it’s swimming. When probiotics are alive, they ferment food (like make yogurt out of milk, sauerkraut out of cabbage, etc). Eat probiotics that you know are alive like live-culture yogurt, kefir, barrel fermented sauerkraut, etc. (To read more, click here for my post Kefir, The Best Probiotic For Healthy Skin.)

Will we see probiotics added to skin care products in a meaningful way?

Maybe.  We don’t know enough to make any recommendations yet though. Like probiotic supplements and “fairy dusted” probiotics in foods, I think the personal care product/probiotic chapter can’t be written until scientists figure out more of the details.

Reference: Germs Are Us, Annals of Science, Michael Specter, The New Yorker, October 22, 2012, (32-39).  Photo: Thanks and Gratitude to Euthman

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