Prebiotics and probiotics both support the body in building and maintaining a healthy colony of bacteria and other microorganisms, which supports the gut and aids digestion.
These food components help promote beneficial bacteria by providing food and creating an environment where microorganisms can flourish.
Prebiotics are present in fiber-rich foods, such as fruits, vegetables, and whole grains. Probiotics occur in many fermented foods, including yogurt, sauerkraut, and tempeh.
Benefits and side effects of probiotics
Probiotics, such as yogurt, can support digestive health.
Research on the effects of probiotics is inconclusive, but it suggests that they may be beneficial in the following areas:
Numerous studies have found that probiotics may improve digestive health in some people.
A 2014 analysis of 24 trials found that probiotics could help prevent the life-threatening disease necrotizing enterocolitis in preterm infants.
A smaller body of research suggests that probiotics may improve mental health.
It is possible that probiotics have this effect because there is a link between gut and brain health.
The results of studies generally suggest that people with disorders affecting the stomach and intestines may see improvements with probiotics.
For example, a systematic review of trials in people with irritable bowel syndrome (IBS) found that probiotics seem to improve the symptoms of this condition. However, the authors caution that it is unclear how significant the benefit may be or which strain of probiotic is most effective.
The authors of a 2017 review of 17 Cochrane reviews considered the evidence supporting the potential benefits of probiotics.
They found that probiotics may decrease:
- the need for antibiotics
- school absences from colds
- the incidence of ventilator-assisted pneumonia
- gestational diabetes
- vaginal infections, such as yeast infections
However, the review did not find high-quality evidence that probiotics can prevent illness, and the authors conclude that more trials are necessary.
According to the same review above, people with Crohn's disease had a higher risk of adverse events when they took a specific probiotic.
People with weakened immune systems were also more vulnerable to side effects.
Other research from the National Center for Complementary and Integrative Health supports the conclusion that probiotics may not be safe for people with serious underlying medical conditions.
A 2018 analysis of probiotic trials warns that many studies do not report safety data, including information on adverse events, even when they claim to prove that probiotics work.
The lack of data regarding safety shows that scientists know little about the risks of probiotics, especially the potential issues of long-term use.
Anyone concerned about the risk of side effects should speak with a doctor before significantly increasing their intake of probiotics.
Benefits and side effects of prebiotics
Most people get enough prebiotics from the diet, without taking supplements.
Prebiotics are a component of some foods that the body cannot digest. They serve as food for bacteria and other beneficial organisms in the gut.
The benefits of prebiotics have links to the benefits of probiotics. Prebiotics may support a healthy gut, offering better digestive health, fewer antibiotic-related health problems, and other benefits.
There is less research on prebiotics than on probiotics.
As a result, the extent to which prebiotics improve health is unclear. Scientists are not yet entirely sure that they can strengthen the purported benefits of probiotics.
Some research suggests that prebiotics may benefit the body by:
- improving calcium absorption
- changing how quickly the body can process carbohydrates
- supporting the probiotic growth of gut bacteria, potentially enhancing digestion and metabolism
Prebiotics occur naturally in many foods, so there is no need for people to take prebiotic supplements.
There is currently no evidence that taking prebiotics and probiotics together is harmful. However, people who have chronic diseases or serious illnesses should avoid probiotic or prebiotic supplements unless a doctor advises otherwise.
Research on the side effects of prebiotics is also in its infancy and requires further investigation.
How prebiotics and probiotics interact
Prebiotics serve as food for probiotics, so probiotics need access to prebiotics to work effectively.
Research assessing the connection between the two is ongoing, and scientists cannot yet confirm whether taking prebiotics can support probiotic development.
People who eat a balanced, varied, and healthful diet will get many prebiotics and probiotics through their food:
Many foods are rich in probiotics, including:
- fermented foods, such as sauerkraut and kimchi
- traditional fermented buttermilk
- fermented cheeses, such as Gouda
By including a variety of foods in their diet, people can ensure that they consume a range of prebiotics that may fuel various strains of bacteria. Prebiotics are in many high-fiber foods, including some fruits, vegetables, and whole grains.
Some probiotic-rich foods may also contain prebiotics.
Babies get access to prebiotics through the sugars in breast milk, and some infant formulas also contain prebiotics.
For most healthy people, there is no need to take prebiotic or probiotic supplements. However, the risk of doing so is usually minimal for people who do not have weakened immune systems or underlying illnesses.
A diet consisting of a variety of fruits, vegetables, whole grains, and fermented foods makes it possible for people to consume sufficient prebiotics and probiotics without relying on supplements.
People should consult a doctor or dietitian if they feel that they need specific advice on the right diet for their needs.