What is a good CFU count, and how much of it do we need?
Colony forming units, or CFUs, are a unit of measurement used to determine the number of bacterial cells in a probiotic supplement, lab sample, or some dairy foods like yoghurt and kefir. High CFU counts are sometimes seen as a quality indicator. Still, it is just one of the factors that determine the quality.
Bacterial strain combination, the delivery mechanism, a person's microbiome (which depends on age, diet, location, and lifestyle), and clinical studies should also be considered when we try to access particular products containing probiotics.
Currently, many probiotic supplements advertise high colony-forming units (CFUs) as the only marker for quality. Therefore, checking the number of colony-forming units has become habitual when choosing probiotic supplements or food like yogurt and kefir. In addition, some companies heavily advertise their superior count. As a result, many people believe that the higher the CFU count, the better. However, this needs to be corrected, and will explain below why.
CFU stands for Colony Forming Units. This means the number of live and active microorganisms in one serving of a probiotic dietary supplement or food containing probiotics. These are typically measured in CFUs per gram or per milliliter.
A colony is the individual colonies of bacteria, yeast, or mold growing together. Bacteria, yeasts, fungi, and viruses are all considered microorganisms.
Probiotic supplements generally consist of good "probiotic" bacteria and yeast. In addition, some fermented food contains yeasts and fungi like kefir, villi, and others.
Probiotic food, like traditional Bulgarian yogurt, is defined by its bacterial combination and should contain L.Bulgaricus and S.Thermophilus only. Some producers call yogurt with other added species "probiotic yogurt" to distinguish between traditional Bulgarian yogurt that includes 2 species and enhanced yoghurt-like food that contains L.Acidophilus, Bifido and others. Kefir is fermented dairy food containing a mix of bacterial species and yeast. Villi contain lactic bacteria, yeast, and a specific fungus usually found in the environment and get to the mixture by the milk.
In microbiology, a colony-forming unit estimates the viable cells of bacteria, yeast, or fungi in a sample. It's easier than counting the number of cells themselves. This is because individual cells are tiny; some may be dead, whereas others are alive.
To measure the number of colony-forming units, a bacterial culture of the microorganism is added to an agar plate (a petri dish with agar solution as a growth medium for the microorganism) in a microbiology laboratory. Often, this requires serial dilutions of the original sample, as the original sample might be very concentrated.
Each healthy bacterial cell should be capable of dividing over and over again, forming a colony of bacterial cells. On an agar plate, the naked eye can count these colonies individually. Total CFU can be estimated from that count. And on a probiotic label, CFU represents the number of live cells in each serving. They're usually counted in the billion, ranging from 2 billion to 75 billion.
It's essential to keep track of the number of times the sample was diluted, also called the dilution factor. If the sample is too concentrated, you will see a large area of bacteria instead of individual colonies.
After a few days of tracking the bacterial growth, the colonies can be seen as a cluster of bacteria or fungi growing together. These colonies are counted. Then you use a specific formula to calculate CFU.
A single colony often has a circular pattern. CFUs matter (especially for probiotics supplements which are shallowed directly) because they indicate how many live beneficial bacterial cells you ingest with your probiotic. The good bacteria you swallow should be alive to be effective.
The average CFU count in probiotic capsules is between 1 and 10 billion CFUs per serving. On the other hand, yogurt producers can add a "live and active cultures" seal on voluntary bases if their yogurt or kefir contains at least 100 million cultures per gram at manufacture. The live and active cultures seal can also be used for frozen yogurt containing at least 10 million cultures per gram at the moment of manufacture.
In recent years, some companies have focused on extremely high CFU counts, claiming that higher CFUs mean better results. However, this is not a universal truth because potency is more than just a number.
The gut contains 400 to 600 different bacterial strains and species comprising nearly 2 million genes (the microbiome). Indeed, the number of bacteria within the gut is approximately 10 times that of all of the cells in the human body, and the collective bacterial genome is vastly more significant than the human genome. Therefore, the goal of taking a probiotic supplement or consuming any probiotic-containing food is to add beneficial bacteria back into the gut so that these bacteria can improve the overall environment in the gut.
Of course, you want to take a high enough quantity of bacteria to ensure these can make a positive difference in the gut. At the same time, taking too high an amount of one or a few specific strains of bacteria may have a negative effect. You might experience digestive upset, or the bacteria will flush through you without having an impact and leave your body.
Instead of focusing on CFUs, we urge you to focus on your probiotic source's efficacy, science, and delivery mechanism. Considering that the number of CFUs isn't an excellent indicator of probiotic quality, here's what you should focus on when determining a probiotic's quality.
1. The combination of Bacterial Strains
Each of the 400 to 600 probiotic bacterial strains in your gut performs a different function. Microbiome research could reveal which strains you need to supply quite precisely, which is frequently difficult or expensive.
2. Clinical Studies and Scientific Evidence
In a ground-breaking study, scientists examined the gut microbiome of identical twins. They concluded that our gut bacteria play a critical role in the metabolic processes in the body and that there is an "intense interplay" between our gut bacteria and our body. Clinical studies on the beneficial effect have been performed for centuries and are still ongoing. Bulgarian yogurt is one of the most researched food. Although studies continue, it is worldwide recognized as a real functional food. The additions of Bifidus, Acidophilus, Rhamnosus, Gasseri Salivarius and Reuteri, recognized as beneficial bacteria, could boost your health if consumed regularly and variably.
3. The Delivery Mechanism
Another critical factor is the delivery mechanism, meaning how the product is manufactured and ingested.
To truly benefit from taking a probiotic, the bacterial species must survive the journey from the manufacturer to the store, to your house, and eventually through your gastrointestinal tract into your large intestine.
This can pose many challenges, including changes in temperature and moisture and exposure to the acid in your stomach.
Unfortunately, in many probiotic supplements, most good bacteria die before you even get the chance to ingest them. And even if the bacteria survive and make it into your mouth, probiotics in capsules and chewable often don't survive the passage through the stomach's acidic environment mainly because they are inactive or dormant. If they survive, they stay like that until they find favourable conditions in the gut.
However, to increase the chances of successfully passing through your body, you must activate and strengthen them. When using the bacterial starter culture and adding it to milk to make yogurt and kefir, you activate the beneficial bacteria, increase the number as they grow and multiply during the fermentation, and make them strong for their passage through the stomach into your intestines.
The acidification of the fermented dairy food additionally guarantees a stable and balanced amount of live and active bacteria(when made fresh with dairy milk, without additives, and with no processing after the fermentation is completed). In this way, the bacterial cultures live in an acidic environment, and they are most adapted and ready to pass through the acidity in the stomach.
Consuming variable and freshly made fermented food (dairy or not) frequently is the only thing that might improve digestion and well-being, as our grandparents used to do.
In the following article, we will learn to recognize if the bacteria are working and how to choose the dosage.