How can I maximize the health benefits of yogurt?
November 13, 2011 9:10 AM   Subscribe

If roughly one hour lapses between the time I remove a container of yogurt from the refrigerated case at Whole Foods, to when I place it inside my fridge at home, does that temperature change kill off most of the live & active bacterial cultures? If I leave the container in the fridge unopened for a few more days, will they repopulate the container? Also, if acidophilus are "acid loving" bacteria, should I be eating yogurt after a big meal, instead of on an empty stomach?
posted by invisible ink to Food & Drink (17 answers total) 2 users marked this as a favorite
The heat required to kill bacteria is much more than the temperature differential between a refrigerated environment and ambient air. Autoclaves operate in excess of 250 degrees F to kill bacteria and other life.
posted by dfriedman at 9:21 AM on November 13, 2011 [1 favorite]

Given that yogurt is cultured at 45 °C / 112 °F, I would think a brief period of being at room temperature could only help the bacteria grow. Its only kept cold to *prevent* further fermentation.
posted by Hither at 9:26 AM on November 13, 2011 [9 favorites]

The bacteria that are still alive in your yogurt when you buy it are mostly dormant at fridge temperatures (they are most active at much higher temperatures in the 30 and 40Cs). If your yogurt was full of thriving cultures at 4C, it would be incredibly sour by the time you bought it. Also, note that 20C air is not going to warm the yogurt up to 20C in an hour - it will still be quite cool.

Eat yogurt whenever you desire, it doesn't make any significant difference. Yogurt is acidic, but not all that strongly so. In any case, it is much less acidic than the contents of your empty stomach.
posted by ssg at 9:40 AM on November 13, 2011

Research in the last few years has shown that probiotics work the same whether they're live or not. They don't populate your intestinal tract either way, any effects are transient. So I don't see how it's going to make any difference, and most yoghurts etc I've seen recently don't bother with live cultures.

Also, only a few specific bacterial types have shown health benefits in a few specific disease states, in which case there would also be literature about the best way ways how and when to take them. If you let us know exactly what you're taking and why then we could give more specific advice? If you're just looking for general 'health benefits' then there aren't really any, so eat it however and whenever you want.
posted by shelleycat at 9:44 AM on November 13, 2011 [1 favorite]

Thanks everyone, for the very informative answers.

Shelleycat- I buy Stonyfield, which has these six:

  • Lactobacillus bulgaricus
  • Streptococcus thermophilus
  • Lactobacillus acidophilus
  • Bifidus
  • Lactobacillus casei
  • Lactobacillus rhamnosus

    and also, Brown Cow which has these four:

  • S. thermophilus
  • L. bulgaricus
  • L. acidophilus
  • Bifidus

  • My primary goal for eating yogurt is to stave off yeast infections. Any information is most welcome, thanks again!
    posted by invisible ink at 10:03 AM on November 13, 2011

    Yogurt with live cultures is very much still alive, as others have said. If you really want to find out just how alive, put a few tablespoons of that Brown Cow or Stonyfield in a few quarts of milk in a pot, cover, and stick in an oven at 120F. 8 hours later you've got a few quarts more yogurt than you had before.
    posted by dis_integration at 10:15 AM on November 13, 2011 [4 favorites]

    Research in the last few years has shown that probiotics work the same whether they're live or not. They don't populate your intestinal tract

    I hadn't heard this! (But am willing to believe it.) Do you have specific studies in mind, or pop news articles about this? Two family members - one human, one cat - were recently prescribed probiotic powder that you can mix into food, after going through heavy antibiotic treatment. Is that just placebo, or a doctor/vet who's behind the times?
    posted by LobsterMitten at 10:20 AM on November 13, 2011 [1 favorite]

    Unfortunately as of this year I'm not currently working in the digestive physiology field so I don't have studies at my fingertips, but I'm thinking specifically of general review papers I've read in the last year plus presentations at nutrition and gut health conferences and meetings. I have also seen unpublished data showing the same results in in vitro studies using either live bacteria or mixtures made of lysed (broken up) dead bacteria, which backs it up. This is all pretty well established by now so shouldn't be difficult to track down (I don't know about pop science writing, I don't tend to read stuff aimed at lay people because it generally pisses me off, heh).

    invisible ink, I don't know much about staving off yeast infections specifically because my background is in IBD, but a quick literature search shows that there may be some evidence (although how good it is is underclear) that some specific types of Lactobacillus *may* have some effects in this area when taken orally (it's also unclear if this leads to actual reduction in infections), although it would take more searching to see if the research actually panned out to anything. This fits what I'm familiar with, very specific substrains of bacteria giving specific benefits to certain patient populations e.g. E. coli Nissle 1917 in Ulcerative Colitis.

    Whereas, but the things you're eating appear to have a laundry list of whatever the company felt like growing at the time. I've never heard of those specific companies because I likely live in a different country, but based just on that list it's pretty clear they aren't therapeutic products aimed at a specific patient population. So just eat it however you want and enjoy the taste, that's the largest benefit you're going to get.

    Lots of vets and doctors and pharmacists and yoghurt companies still believe probiotics are a wonderful cure all, but the science just isn't bearing it out. But they make money and they generally don't hurt anyone, so it persists.
    posted by shelleycat at 10:46 AM on November 13, 2011 [2 favorites]

    Oh, that first paragraph was aimed at LobsterMitten. And my editing in general sucks.
    posted by shelleycat at 11:02 AM on November 13, 2011

    I purposely leave my yogurt out on the counter at least overnight, and sometimes a day, so that it gets more sour. I concur that your yogurt is ok.
    posted by small_ruminant at 11:15 AM on November 13, 2011

    Transporting yoghurt from Whole Foods to your house shouldn't have anything other than a negligible effect on the cultures inside of it, these are commercial strains, which means they have to be hardy as fuck.

    The acidophilus in the name comes from the fact that Lactobacillus acidophilus does best at pH levels below 5, but your stomach is generally between 1 and 2, which is one to ten thousand times more acidic. It is still pretty resistant to gastric acid but doesn't like it. Eating the yoghurt with a full meal will significantly increase the number of cells that remain viable when they get to your small and large intestines. Additionally, and please don't do this, consuming an antacid with the yoghurt would also let more cells through.

    "Research in the last few years has shown that probiotics work the same whether they're live or not. They don't populate your intestinal tract"

    The effect that probiotics have is has been plainly demonstrated to be intensely context dependent, but if you are an otherwise healthy adult, the cultures in store bought yoghurt are not especially likely to actively colonize you in such a way as to have much effect on yeast infections. That isn't to say that it won't do it or that eating yoghurt isn't worth doing for this reason.

    Repeatedly exposing healthy adults to monocultures of individual commercially useful strains has yet to be shown to have any measurable health effect. However, that is not to say that consuming foods with the intention of positively affecting your gut microbiota is a worthless exercise. Make your own yoghurt, saurkraut, kimchee, tempeh, vinegar, or booze.

    If you want a ridiculously plural culture of kombucha I can bring some with me when I stop through DC for Christmas.
    posted by Blasdelb at 11:39 AM on November 13, 2011 [2 favorites]

    My primary goal for eating yogurt is to stave off yeast infections. Any information is most welcome, thanks again!

    When I had this problem, eating yogurt didn't do much for me. Applying it, um, directly made a big difference, though. A lot of women in this thread seem to agree.

    Over the long term, what finally fixed it for me was diet change; I switched from vegetarianism to a meaty low-carb diet, and I haven't had a yeast infection since. I must've been missing something in my diet. I was a lazy hummus-and-tortilla-chips-for-dinner vegetarian, though, so your mileage will probably vary!
    posted by vorfeed at 12:04 PM on November 13, 2011 [2 favorites]

    I hadn't heard this! (But am willing to believe it.) Do you have specific studies in mind, or pop news articles about this?

    Coincidentally I just saw a reference to it on boingboing a few weeks ago. Pop article about a recent study.
    posted by hattifattener at 12:20 PM on November 13, 2011 [1 favorite]

    I should also note that there are safe and effective treatments available that your doctor or gynecologist can prescribe.
    posted by Blasdelb at 12:21 PM on November 13, 2011 [1 favorite]

    Mrs. lab.beetle had chronic yeast infections for years. She finally cured them with a combination of dietary changes (less sugar) and boric acid suppositories.
    posted by lab.beetle at 1:03 PM on November 13, 2011

    I can only stand so much yogurt, but I've found that acidophilus keeps my digestive tract in good shape - this over many, many years of trial and error. I'm old now and have a whole range of ailments, but I've avoided a few that I'm certain the acidophilus has kept at bay. I take prednisone via an inhaler through my mouth, but have never had a Candida infection, haven't had a yeast infection in 25 years, was recently told my colon is in such fine shape I don't need another colonoscopy for 10 years(!) - and all are thanks to acidophilus.

    I go to the health food store and buy live-culture acidophilus capsules that must be kept refrigerated. I take one a day unless I'm on antibiotics, when I take two or three a day. If I remember correctly, each capsule is equal to approximately eight small tubs of yogurt.

    Acidophilus capsules have been broken into warm water and used as a douche for recurrent yeast infections also. I don't know if that works, but it would also be worth a try if you've been struggling with recurrent yeast infections over a long period of time, indicating a yeast colony that's settled in and happy there.

    Probiotics, via yogurt or capsules, are inexpensive and have helped many people avoid doctor visits and expensive (and often ineffective) medicines; to me, that would be worth a try.
    posted by aryma at 12:54 AM on November 14, 2011

    Science Friday on NPR interviewed a guy a few weeks ago who studies this question. He had recently published a major study about how and whether probiotics and yogurt have any effect on the digestive system. The gist of it was that the bacteria in yogurt don't grow and repopulate your intestines, but they do somehow change the behavior of the bacteria that already live there. You can listen to the recording here, and the abstract of the article is here.

    my colon is in such fine shape I don't need another colonoscopy for 10 years(!)
    This is the generally accepted time frame between normal colonoscopies -- colon cancer grows so slowly, that even if something cancerous did start to grow the week after your colonoscopy, it would still be small enough to deal with easily when they see you again in 10 years. Not to disparage the health of your colon, because that's great news! I just want people to know that a 10-year follow-up schedule signifies "nothing looks like potential cancer right now," not "holy cow you have the healthiest colon we've ever seen!"

    posted by vytae at 8:44 AM on November 14, 2011 [1 favorite]

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