Probiotics During Cold Season?

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Probiotics During Cold Season?

Babies delivered via caesarean section appear to be at increased risk for various allergic diseases. The thought is that vaginal delivery leads to the first colonization of the baby’s gut with maternal vaginal bacteria. C-section babies are deprived of this natural exposure and have been found to exhibit a different gut flora. This concept is supported by research noting that a disturbance in maternal vaginal flora during pregnancy may be associated with early asthma in their children. This all suggests our natural gut flora can affect the development of our immune system (for better or for worse).

In adulthood, two studies published back in 2001 suggested that probiotics could have systemic immunity-enhancing effects. Subjects given a probiotic regimen saw a significant boost in the ability of their white blood cells to chomp down on potential invaders. (You can watch a video of white blood cells doing their thing in my video Clinical Studies on Acai Berries. A must-see for biology geeks :). And even after the probiotics were stopped, there was still enhanced immune function a few weeks later compared to baseline (check out my 4-min video Preventing the Common Cold with Probiotics? to see the graph). A similar boost was found in the ability of their natural killer cells to kill cancer cells.

Improving immune cell function in a petri dish is nice, but does this actually translate into people having fewer infections? For that, we had to wait another 10 years, but now we have randomized double-blind placebo controlled studies showing that those taking probiotics may have significantly fewer colds, fewer sick days, and fewer symptoms. The latest review of the best studies to date found that probiotics, such as those in yogurt, soy yogurt, or supplements, may indeed reduce one’s risk of upper respiratory tract infection, but the totality of evidence is still considered weak, so it’s probably too early to make a blanket recommendation.

Unless one has suffered a major disruption of gut flora by antibiotics or an intestinal infection—in other words unless one is symptomatic with diarrhea or bloating—I would suggest focusing on feeding the good bacteria we already have, by eating so-called prebiotics, such as fiber. After all, as I noted in Preventing and Treating Diarrhea with Probiotics, who knows what you’re getting when you buy probiotics. They may not even be alive by the time we buy them. Then they have to survive the journey down to the large intestine (Should Probiotics Be Taken Before, During, or After Meals?). Altogether, this suggests that the advantages of prebiotics—found in plant foods—outweigh those of probiotics. And by eating raw fruits and vegetables we may be getting both! Fruits and vegetables are covered with millions of lactic acid bacteria, some of which are the same type used as probiotics. So when studies show eating more fruits and vegetables boosts immunity, prebiotics and probiotics may be playing a role.

How else might we reduce our risk of getting an upper respiratory infection? See:

The immune boosting fruit and vegetable video I reference in Preventing the Common Cold with Probiotics? is Boosting Immunity Through Diet. See also Kale and the Immune System and the subject of my post last week, Boosting Immunity While Reducing Inflammation.

-Michael Greger, M.D.

PS: If you haven’t yet, you can subscribe to my videos for free by clicking here and watch my full 2012 – 2015 presentations Uprooting the Leading Causes of Death, More than an Apple a Day, From Table to Able, and Food as Medicine.


Michael Greger M.D., FACLM

Michael Greger, M.D. FACLM, is a physician, New York Times bestselling author, and internationally recognized professional speaker on a number of important public health issues. Dr. Greger has lectured at the Conference on World Affairs, the National Institutes of Health, and the International Bird Flu Summit, testified before Congress, appeared on The Dr. Oz Show and The Colbert Report, and was invited as an expert witness in defense of Oprah Winfrey at the infamous "meat defamation" trial.

8 responses to “Probiotics During Cold Season?

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  1. I was gluten free and vegan for 4 1/2 yrs. I even got diet advice directly from one of the most prominent vegan/vegetarian doctors in the nation, but I only became sicker while eating this way. Hypothyroid worsened, developed PCOS, energy became very low, and worst of all chronic constipation (as in every single day) and bloating worsened. A couple yrs ago I was diagnosed with Small intestine bacteria overgrowth. The above mentioned doctor said to try Xifaxan and reduce high FODMAP (=Fermentable Oligo-Di-Monosaccharides and Polyols) foods. This did not help. I had to go a step further and eliminate all fruits and veggies except well cooked carrots and zucchini, all legumes, all grains and potatoes, all dairy except raw goat cheese, in order to get rid of the bloating and get some energy, constipation has improved but only very slightly. I’ve been using dextrose as a carb source to avoid ketosis. There are others in my same predicament. Do you have any advise for us??

    1. When reading your comment this came to mind: 1) Small intestine parasite infestation that has not been eliminated; and 2) A need for special high colonic therapy and gut re-colonization techniques and nutrients. Perhaps you may want to engage a complementary and alternative medicine (CAM) MD or DO who understands the above and can guide you. Just a thought with good wishes for relief.

      1. Thanks for the reply! I have already worked with and continue to work with several different CAM, holistic, and conventional practitioners. The majority of them do suspect parasites in addition to the bacteria overgrowth, and although they have different suggestions as to meds and supp’s, they do all suggest to avoid all foods that exacerbate gastric distress. Through various elimination diets I have determined that in addition to gluten and junk food, fresh fruits and vegetables, and anything high fiber or starchy are the worst offenders. As a staunch natural foods proponent it was hard for me to give up on salads, green smoothies, and veggie soups, but it has provided some relief. As for colonics they only seem to provide relief for a few days afterwards then back to normal. I’ve tried many different probiotics in order to repopulate with good bacteria (VSL#3, Align, soil-based, etc.), none have helped at all. I have not tried Fecal transplant but from what I’ve read it only helps with C-diff and disorders centralized in the lower intestine, not so much for disorders higher up in the small intestine and not for motility disorders. Thing is, via forums and other social media, I have found I am not alone! Many others who have yeast or bacteria overgrowth and/or parasites have had to eliminate many healthy foods in order to get relief from their symptoms. What do we do if we cannot digest these wonderful healthy foods?

        1. Just choose 1 gastroenterologist to make a colonoscopy and a fibroscopy to determine from the 2 ends of your digestive tube what is right and what is wrong, Ask him to prescrive simple blood tests to evaluate a possible parasite, infection or allergy, then with these results start to design a nutrition plan with a professional with a specific treatment if necessary.Stop fashionable diet, the best MD do not need ad and fantasy, they know what to do face to a patient. Each patient is unique and do not waste time with advice that will not work for you.

          1. I have had the colonoscopy and fibroscopy. The results show twisted colon, hiatal hernia, she also gave a breath test and that was how I was diagnosed with small intestine bacteria overgrowth. My gastro doc, the one who gave me those tests, said I should go on the low FODMAP diet. She explained to me the molecular research behind it. I then consulted with one of the top vegan nutritionists (he is also a M.D.) in the country, he also said to eliminate high FODMAP foods, he also said to take VSL#3, but it did not help. He said eventually I would be able to digest better but after 4 1/2 yrs, I was only worse. I asked about allergy testing, he said the IgE antibodies test is not entirely reliable, and that I need to do an elimination diet to find out for sure. The Xifaxan the GI doc gave me did not work, I’ve also tried antifungals. She says she is sorry that she does not have any more answers for me aside from avoiding foods that make my gastro symptoms worse. There is another thing that she suggests and that is to take more and higher strength of antibiotics but that it will likely only be a temporary solution. I do not do any “fashionable diet”. I just try to avoid the things that cause gastro issues for me specifically. It just so happens that others find that fresh veggies/fruits and starches cause digestion issues as well. Thank you kindly for your suggestions though.

            1. My website is you can register for free and I will answer. You have different issues and you have to take care of each one by one to be OK in minimum few months. The hiatal Hernia is simple to treat and important as it is a painful handicap. Starting with it you may improve your general digestion. Digestion is kind of cascade of reactions with signals, when you start to quiet the first issue, the tolerance for many nutriments improves and after a while you are surprise to feel better and have an easier”normal” life.

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