Over the past decade, the consumption of probiotic dietary supplements has been increasing steadily. You walk into any drugstore, and there are so many different brands, it gets confusing. What exactly are probiotics? How do they benefit our health? Are there any risks of taking probiotics? These questions will be addressed in today’s post.
According to the World Health Organization, probiotics are defined as live microorganisms that, when administered in adequate amounts, confer a health benefit on the host. So, in other words, probiotics are good germs (bacteria or fungi) which help us to be healthier, when they are taken in the correct amounts. There won’t be a health benefit, if the amount taken is too small.
How do probiotics benefit our health?
1 – They have ‘antibiotic’ effects Probiotics facilitate the production of various chemicals which can be toxic to bad germs, preventing their growth or outright killing them. Additionally, taking probiotics results in the presence of larger amounts of good germs, which means less space for bad germs (‘competitive inhibition’).
2 – They enhance the barriers of the gut to infection Probiotics stick to the lining of the bowel wall, resulting in a barrier which prevents the bad germs from passing through and causing infection. Probiotics also compete with bad germs for limited ‘food’ resources, iron being a big one.
3 – Immune system enhancement Probiotics can stimulate the production of protective cytokines, which can prevent destruction of the protective cells lining the bowel wall. They may also enhance the immune system in the gut, enabling increased protection against harmful organisms.
Probiotics are not safe for everyone
Probiotics are for the most part, considered safe. However, because probiotics are live microorganisms (actual germs), they have the potential to cause infections.
Persons at risk for infection with germs present in probiotics, include those with very weakened immune systems such as those with cancer on chemotherapy, persons who have had organ transplants, and persons with uncontrolled diabetes. I remember once having a patient with severely uncontrolled diabetes, who had an infection in his blood stream from a Lactobacillus species. This is one of the most common bacteria in probiotic supplements.
Another group of persons at risk for complications from taking probiotics, are those with artificial devices in their bodies, such as prosthetic joints and heart valves, and cardiac pacemakers, for example.
Bacteria and fungi, including those contained in probiotic supplements, can transiently get into the blood stream. However the immune system, if working well, can quickly remove these microorganisms before they get a chance to cause infection. Unfortunately, because the immune system does not work well on artificial surfaces, bacteria can get lodged (stuck) onto foreign devices, and over time cause infection. (This mechanism of infection was explained in more detail in last week’s post.)
Another nagging issue with the safety of probiotics, is the fact that the dietary supplement industry is not very regulated. FDA approval is not required before putting probiotics on the market. There have been situations where companies have mislabeled contents of the supplements, even listing names of microorganisms that do not even exist!
In next week’s post, I will give some examples of foods containing probiotics, and tips on choosing a probiotic supplement.