This post may contain affiliate links. Please read my disclaimer for more info.

greek yogurt with granola and berries

Listen to Dr. Neal address this topic on Episode 435 of the podcast Optimal Health Daily.

My wife was watching some Golden Girls reruns on TV the other day.

“Why?” you may wonder.

It brings back fond memories. When she was a kid, her parents would allow her to stay up late on Saturday nights and watch the show. She says she would usually fall asleep in front of the television set before the show ended and now, she can finally watch them in their entirety – and understand the jokes. But, anyhoo, while she was watching there just happened to be a commercial for a probiotic supplement that promised to help “keep you regular.”

Are Probiotic Health Claims Really True?

We have lots of good bacteria found in the gut–we’re talking LOTS of them–it is estimated that each person has anywhere from 10-100 trillion of these good bacteria in our intestines. And remember, these are good bacteria; they help keep us healthy.

What’s amazing is that each person’s microbiome is different. There are lots of different strains or species of these good bacteria within each person, but in different quantities. It is believed there are at least 400 different species of these good bacteria within each person. It’s these different quantities that make everyone’s microbiome unique to each person.

What are Probiotics?

They are live bacteria that support the health of our microbiome. And, yes, foods like yogurt, Kefir, and Yakult contain lots of probiotics. The trouble is we don’t really know how helpful these foods are when it comes to actually increasing the number of good bacteria in your gut. This is because these foods have to first pass through the stomach before they get to the intestine. The stomach is a pretty harsh environment for most things. It’s possible that many of those good bacteria are destroyed before they get to the intestines, where they can thrive. As always, I have to rely on actual studies to find out whether probiotics are helpful. Luckily, there are plenty of those!

Based on the data I have seen, there are some probiotics that are showing promise for helping reduce the symptoms of certain conditions. For example, there are some that may help reduce the symptoms of Irritable Bowel Syndrome (IBS), like diarrhea and cramping.

What about other conditions where the symptoms don’t seem directly connected to the gut, like the common cold?

Some studies have found that supplementing with certain strains of probiotics may reduce the likelihood of getting a cold or, if you do get sick, reduce how long the cold will last. Supplementing with 2 strains of Lactobacillus–Lactobacillus plantarum and Lactobacillus paracase–seem to be the most helpful.

There are also some data that support the use of S. salivarius in reducing risk of viral or bacteria-causing throat infections. As far as these throat infection studies go, researchers have only looked at children so we don’t know if we’d see the same results in adults.

Does Probiotic Supplementation Help with Weight Loss?

With regards to probiotic supplementation and weight loss, we need more and better designed studies to understand what’s going on. Many of the studies are sponsored by companies that may have a financial stake in the findings, like the Nestle company for example. These companies will create formulations of these products and then give money to researchers to try them out. That can quickly pose a conflict of interest, pressuring the researcher to find a positive result.

Probiotics & Other Conditions

Researchers have also studied strains of probiotics on cholesterol and even anxiety and depression. For lowering “bad” or LDL cholesterol levels in the blood, a combination of Lactobacillus acidophilus and Bifidobacterium lactis may help. But don’t expect it to dramatically lower these bad cholesterol levels–if it does help, it may only lead to a modest lowering.

When it comes to anxiety and depression, an association between gut health and these conditions has been established. Researchers have started to examine whether improving gut health can also improve anxiety and depression. The research is promising, but what’s not so clear is which probiotic strains appear to help. Right now, there appear to be 2 strains that may help: Bifidobacterium longum and Lactobacillus helveticus.


In summary, there are many probiotic strains out there. Here are the ones that I’ve mentioned so far:

  • Lactobacillus plantarum and Lactobacillus paracasei – potentially prevent colds
  • S. salivarius – may help prevent throat infections in children (we need more studies with adult participants)
  • Lactobacillus acidophilus and Bifidobacterium lactis in combination – possibly help lower “bad” LDL cholesterol levels
  • Bifidobacterium longum and Lactobacillus helveticus – may help with anxiety and depression

We must also be careful before supplementing with probiotics, as well. As I’ve mentioned many times before, the supplement industry is kind of like the Wild West right now. Supplement manufacturers are creating products that aren’t being tested by independent third parties, so they are putting fillers in their products and marketing them as supplements. It is very possible that you could go out and purchase what you think is a probiotic supplement, but if we were to actually analyze the product to see what it’s truly made of, we might find it contains no good bacteria at all. Or if the product does contain good bacteria, there aren’t enough of them to make a difference. Most of the studies suggest that getting doses of 1 billion live probiotic cultures may be what’s required in order to see any beneficial effects.

With regards to proper storage of these probiotics, some require refrigeration whereas others may be stable at room temperature. It really depends on the brand and the probiotic strains. Carefully read the packaging to find out how best to store the probiotic. And, as always, if you decide to begin supplementing (with anything really), speak to your primary healthcare provider first.

Listen to Dr. Neal address this topic on Episode 435 of the podcast Optimal Health Daily.