You may have heard the term probiotics floating around recently – especially among people trying to boost their health. But, what are probiotics specifically? And, why are probiotics good for you?
Because make no mistake, they really are. In fact, probiotics are much more important to health than most people realize. The reason for this is related to an aspect of health that we often overlook, our gut.
The Significance of Gut Health
Collectively, the human body contains a large range of bacteria. Many of these bacterial species coexist with us and have no significant impacts on the body. But, some are in a mutualistic relationship, which means that the bacteria benefit, as do we. That pattern is especially common in the digestive tract.
In fact, the human gut contains more bacteria than other parts of the body, along with a greater diversity of bacteria. This pattern means that what is in our gut has an absolutely critical impact on overall health.
For that matter, the gut itself is very important to health. Some estimates suggest that around 70% of the immune system is located in the gut (1), making it critical for fighting diseases and allergies.
The bacteria found in our gut is collectively referred to as the gut flora or gut microbiota. Functionally, this collection of bacteria is similar to an organ and is sometimes referred to as the ‘forgotten organ’ (2).
Modern research is increasingly suggesting that gut health is critical to overall health and wellbeing. Additionally, some behaviors and decisions around food can compromise the bacteria in our gut, potentially increasing the risk of disease.
So, it’s clear that the distribution of gut flora is important – but what are the implications for health?
Well, the various species can play different roles. Some of them act to ferment dietary fiber, while others play a role in synthesizing vitamins and other useful compounds (3).
Having a good balance of gut bacteria has also been linked to a range of health benefits, which will be highlighted later on.
Compromised Gut Flora
There are also cases where a person’s gut flora may be significantly compromised and this can have dramatic impacts on health.
Some theories suggest that this situation can increase disease risk and lower the function of the immune system as a whole.
For example, antibiotics are commonly used to treat a range of conditions (even though they are often overprescribed). However, the medication doesn’t discriminate between types of bacteria – so it harms the gut flora as well as unhealthy bacteria (4).
As a consequence, people who have been on antibiotics often have compromised gut bacteria and this often will not recover on its own (5).
Some of the food we eat may also harm the balance of bacteria in our gut, as can some health conditions.
Some research also suggests that diets high in fat and in sugar can cause damaging changes to gut bacteria (10,11). This type of change and result in lower cognitive flexibility, which refers to the ability to adjust to changes in a person’s situation.
Additionally, there is growing evidence that artificial sweeteners may also harm gut bacteria (12) – and even just eating junk food periodically may cause damage, especially when this leads to overeating (13).
All of these patterns are concerning and mean that many people have lower levels of healthy bacteria than they need.
Promoting a good balance of bacteria in the gut is important for anyone and may offer significant health benefits. But, this pattern is particularly relevant for those who have lower-than-normal levels of gut bacteria.
A simple way around these issues would be to focus on a diet that is heavy in whole foods, where you are cooking most (or all) of your meals, rather than relying on processed alternatives.
If you also consume significant amounts of fruit and vegetables, you also boost your gut microbiome due to the presence of prebiotics, which are basically the food that your gut bacteria consume.
In many cases, you may also need to focus on getting probiotics into the diet, and we’ll talk about this area a little later on.
Research and Directions
The health of our gut microbiome is still a fairly new field and research is mostly in its early stages.
To make matters more complicated, the gut microbiome is vast, containing many different species of bacteria, each of which may have its own implications for health (14). Furthermore, the distribution of gut bacteria varies from one person to the next, often dramatically (15).
As a result, we are still learning all of the implications of gut bacteria for health, along with how to promote the best outcomes. Nevertheless, there is more than enough research to show that gut flora is critical to overall health.
What are Probiotics?
The field of probiotics strongly ties into the gut microbiota. According to the FAO and WHO, the term is defined as follows (16):
“live microorganisms which when administered in adequate amounts
confer a health benefit on the host”
The concept is that probiotics help to increase the diversity and number of bacteria present in the gut, which then serves to boost health benefits overall.
Such an impact is particularly true for people whose gut flora has been compromised in any way, such as those who have been on antibiotics.
Probiotics fall into two general categories.
The first of these is probiotics from food. The is the key reason that fermented foods are good for you, as bacteria are a key component of the fermentation process. As a result, various fermented foods can be a powerful way to promote a good balance of bacteria in the gut. Plus, many of them also taste amazing.
The simplest example would be probiotic yogurt and many studies have shown this yogurt can help promote positive digestion outcomes (17,18,19). For that matter, yogurt is a common choice for probiotic research and there are many healthy types to choose from.
However, if you do go with yogurt, make sure you pick a brand that actually contains healthy bacteria – as that isn’t always the case. Additionally, it’s important to pay attention to the species of bacteria that are present, as different products will vary in what they include and there may be multiple species present.
There are many other products out there but one other popular option is kombucha, which is typically a type of fermented tea (although it can also be made with coffee). Kombucha is also very popular because you can make it at home, such as with the kit below.
There are also many guides for making kombucha. For example, Wellness Mama talks about the benefits of kombucha and how to make it for yourself. The site Whole Natural Life offers details for another type of fermented drink - kefir.
The other category for probiotics is supplements. Like with yogurt, probiotic supplements often contain multiple types of healthy bacteria and the strains vary from one brand to the next.
This type of supplement can come in many forms, such as a powder or a pill. One example is the product below, which also acts as a good starting point for supplementing with probiotics.
Why Are Probiotics Good for You?
The simple answer about probiotics and health comes back to the topic of gut bacteria. Ideally, probiotics help increase positive bacteria in the gut, potentially resulting in health benefits overall.
As with gut health itself, research into this field is still ongoing. But, there is considerable evidence that probiotics can help to improve health.
Probiotics have also been linked to other health benefits, such as fighting migraine headaches (24).
Finally, there is increasing interest in the link between probiotics, gut health and mental illness. For example, conditions that involve anxiety and depression have been associated with more permeability in the gut (25).
Research has also shown differences in microbiota composition between people with major depressive disorder and those who do not (26), although cause and effect has not yet been proven.
One animal study even showed that transplanting ‘depression microbiota’ tended to result in depression-like symptoms, while the reverse did not (27). This pattern strongly suggests that gut bacteria may directly influence depression symptoms.
This isn’t especially surprising, as there is an association between what people eat and their brain function, which is particularly relevant for mental illness.
Probiotics have also been found to significantly affect interactions between the gut and the brain (28). This could also be the reason that probiotics may help with migraines (29,30), especially as there is a connection between migraines and gastrointestinal disorders (31).
With all this in mind, there is the potential for probiotics to help reduce some symptoms of depression. Some research with supplements supports this theory, although more evidence is needed (32,33,34,35).
Taking probiotics at the same time as antibiotics may also help to prevent and treat the diarrhea that antibiotics commonly cause (36). Likewise, probiotics can help with conditions like inflammatory bowel disease (37,38) and may play a role in fighting cancer (39).
However, not all research has agreed. For example, one study pointed out that findings on anti-inflammatory, antioxidant and HbA1c effects have been inconsistent across studies and that more research is needed (40).
From all this information, it’s clear that the bacteria in our gut plays a large role in health. In fact, there are many other potential interactions that have yet to be studied in any detail.
Even though we don’t know all of the mechanisms involved, these patterns strongly suggest that probiotics can help to promote health. Plus, many probiotics offer benefits of their own, especially the options that come from food.
Choosing the Best Probiotics
With research ongoing, it isn’t clear what the absolute best choices for probiotics are. In fact, many of the meta-analyses into the field simply considered any type of probiotic addition, regardless of the type of bacteria and whether it was food or supplement-based.
Furthermore, it’s likely that the impacts of specific probiotics will vary depending on the individual person and the state of their gut microbiome (41).
With this in mind, one of the best answers may simply be to vary the types of bacteria that you take through probiotics. After all, the gut microbiome is diverse and the various bacteria have different roles. As a result, consuming different types of bacteria through probiotics is likely to offer the best overall outcomes.
To do this in practice, you could choose to increase the amount of fermented food in your diet, while also using a using a probiotic.
It may also be worth paying close attention to the way that your body responds. After all, we do have different gut flora from one another. This means that some people may see benefits from a particular product or strain of bacteria, while others may not.
Likewise, some people are likely to see more benefits than others, especially if their gut microbiome was compromised in some way.
One final approach may be to try and find specific bacteria, as some strains have been studied more than others. For example, the site Dr. David Williams highlights five different bacterial strains that he considered to be powerful, one of which is Lactobacillus acidophilus.
Choosing bacteria in this way could be beneficial, especially if the research lines up with a particular health condition that you have. However, do be aware that the research is still incomplete and many strains have not been studied in depth.
As a result, the most powerful approach is still to vary the bacteria and not stick to a single strain.
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