While browsing through my science news items this morning, I came across an article discussing the effects probiotics have on heart health. Seeing as I haven’t yet discussed probiotics on this blog, I thought this would make a good opportunity.
The article was published in Authority Nutrition. Within there are many citations, and appears to be evidence based, but does the evidence actually support the claim? Turns out not really.
Probiotics: A review
Before I get into the article, I want to make sure everyone is on the same page when it comes to probiotics.
The definition of probiotic is officially described as: denoting a substance that stimulates the growth of microorganisms, especially those with beneficial properties (such as those of the intestinal flora)
Before researching for this post, I was under the impression probiotics were a recent invention (within the last few decades) and was surprised to find that the idea is much older.
The hypothesis that your gut microbiome (the good bacteria living within your gut) could be altered was first coined by Russian scientist and Nobel laureate Élie Metchnikoff, who in 1907 believed that aging was caused by bad bacteria that excreted harmful substances into the gut. These toxic molecules then act on the body and cause characteristics of old age.
After witnessing that certain European countries who drank milk fermented by lactic-acid bacteria had relatively long healthy lives, Metchnikoff decided to incorporate the sour milk into his diet. Soon afterwards he had convinced many of his colleagues, and doctors were prescribing sour milk to treat various ailments.
After the initial sour milk product, many foods have been developed and labelled through the decades as a probiotic; including yogurt, buttermilk, kombucha fermented tea, and sauerkraut.
Recently, probiotics have gained momentum with the release of probiotic pill captures, or fermented drinks (such as kombucha) containing what is believed to be good bacteria meant to alter your gut flora and cure a plethora of diseases.
And the data suggests that the usage of probiotics has increased with the release of these new products. Data from the 2012 National Health Interview Survey show about 4 million U.S. adults use or have used a probiotic.
Nowadays, you can’t enter a grocery store without seeing 10 different brands of probiotics, all promising to cure disease or maintain gut microbiome diversity.
The Science Behind Probiotics:
When you type in the keyword probiotic into PubMed, 18,605 results are returned, with an exponential growth starting in the early 2000’s. However, much of the data coming out suggests probiotics are not as beneficial as companies would have you believe (as always).
Much research has been preformed discussing what scientists call the microbiome (the variety of bacteria that exist within us or on us , primarily referring to the intestine and skin.
Evidence suggests that an unhealthy microbiome with the wrong type of bacteria, or too little of good bacteria can contribute to many health defects. Those with disrupted microbiota can experience digestive tract issues, and possibly have an increased risk of developing heart disease, diabetes, weight gain, and many other medical issues. While the evidence is young, there does appear to be a link with the gut microbiome and many diseases we fight today.
Recent mice studies further confirm this hypothesis. Unhealthy mice who receive a microbiome replacement with the microbiome of another healthy mouse, under go a great change. One example shows that mice who are typically more afraid (hide, don’t jump from ledges, etc..) and get their microbiome replaced with mice who are more courageous, appear to become more brave. Other studies have shown that normal mice who get a microbiome replacement with obese mice end up actually gaining weight to similar levels as the original obese mouse.
This preliminary data needs to be further evaluated, but it does bring forward an interesting discussion of how microbiomes make up our human personality.
And so, probiotics on the surface have the potential to modify our microbiome and increase the health of those who take them by replacing them with beneficial bacteria. It seems that probiotics have in general two types of bacteria; Lactobacillus and Bifidobacterium.
However, these probiotics have mixed effects when it comes to the claims companies promote. In short, they are not the miracle cure.
Probiotics have been shown to relieve symptoms of certain medical ailments, such as inflammatory bowel disease, irritable bowel syndrome, or diarrhea caused by antibiotics. These however have not been conclusively tested, and much more work needs to be completed before we can actually consider probiotics a valid treatment.
What does seem to be clear though, is that if you are not suffering from a true, diagnosed medical disease, there is little or no benefit of taking probiotics. So don’t think of probiotics as something everyone should be taking. And if you have a compromised immune system for whatever reason, there is a risk of developing infections. Therefore, it is best to avoid probiotics.
Probiotics Contributing to Healthy Hearts:
Getting back to the article I initially found today, what I found was even more suspicious evidence suggesting probiotics are able to prevent heart disease and lower cholesterol.
The article is titled “Do Probiotics Benefit Heart Health?” and is on the surface a well cited article with what appears to be good information. The news item covers several review meta-articles that suggest probiotics decrease your cholesterol, your blood pressure, inflammation, and triglycerides.
However, after checking the sources my suspicions were confirmed.
Several review articles were cited, each being a meta-analysis of multiple studies involving human subjects. Almost all of which seemed to be double blind, placebo control studies. And there does appear to be at least some interesting data. However, these articles to the best of my knowledge are not using commercially available probiotics. In fact, I had a difficult time trying to find out exactly how much bacteria was added, and how it compares to those on the market.
In addition, I also found articles published in journals such as BMC Complimentary and Alternative Medicine that publish articles supporting traditional Chinese medicine (in children I might add), acupuncture, and other pseudo-scientific methods. This suggests to me the “peer review” of these journals may not stand up to the standards of evidenced based articles.
Being as probiotics are a drug, you would expect to find any evaluation of the proper dosage and potential toxicity (in this case probably likelihood of infection), but I found none.
All in all, the evidence provided by this news item does not impress me. It is impossible to prove anything in science, but these articles to me fall extremely short of suggesting probiotics contribute to lowering cholesterol or cure heart disease. The news items does not explicitly say that probiotics are the miracle cure, but I don’t believe it leaves the viewer with an accurate statement of the current research, and is not as evidence based as it suggests. There was however one true statement in the news item. Every article mentioned used patients either with high cholesterol, high BP, or high triglycerides. Therefore we cannot make the claim probiotics prevent high cholesterol or high BP
So far, I cannot conclusively say probiotics are completely useless. There does seem to be preliminary evidence suggesting benefits to those with medically diagnosed diseases, and the evidence of reducing cholesterol levels and preventing heart disease is shaky at best.
There seems to be no evidence suggesting it should be taken for normal healthy individuals, and there is too much discrepancies between the companies to suggest all of them work the same. If indeed there is a benefit towards ingesting one type of bacteria, the probiotic industry needs to police themselves and use the proper amount and type of bacteria shown to be clinically effective. There is very little evidence on safety of probiotics, and little evidence on efficacy over long periods of time.
To wrap up, until more evidence is released showing probiotics are more effective, and the probiotics are controlled by an agency responsible for developing them safely, stay clear of probiotics.
Thank you for reading. I hope you learned something. I know I did.
If you have any comments, suggestions, or sources you would like to share with me, please do not hesitate to leave a comment below. You can always email us at firstname.lastname@example.org, or find us on Facebook and Twitter.
As always, remember to stay curious, and be mindful!
Please note that is article is not intended to be medical advice. If you are struggling with a medical disease, please refer to a physician for proper advice and treatment.
- Arteriosclerosis and intestinal poisons. [a contemporary review of Metchnikoff’s work] JAMA1910, 55:2311-12.
- Featured Image Credit: https://benefitsofprobiotics.com/probiotic-supplements-gut-health/