4. Some Ingredients May Cause Adverse Reactions

People with allergies or intolerances should read the labels of probiotic supplements carefully, since they might contain ingredients they could react to.

For example, some of the supplements contain allergens such as dairy, egg or soy.

These ingredients should be avoided by anyone who is allergic, as they may trigger an allergic reaction. If necessary, read labels carefully to avoid these ingredients (32).

Similarly, yeast-based probiotics should not be taken by those with yeast allergies. Instead, a bacteria-based probiotic should be used (33).

Milk sugar, or lactose, is also used in many probiotic supplements (34).

While studies suggest that most people with lactose intolerance can tolerate up to 400 mg of lactose in medications or supplements, there have been case reports of adverse effects from probiotics (35, 36, 37).

Since a small number of people with lactose intolerance may experience unpleasant gas and bloating when consuming lactose-containing probiotics, they may want to choose lactose-free products.

In addition to containing powerful probiotics, some supplements also contain prebiotics. These are plant fibers that humans cannot digest, but that bacteria can consume as food. The most common types are lactulose, inulin and various oligosaccharides (38).

When a supplement contains both probiotic microorganisms and prebiotic fibers, it is called a synbiotic (39).

Some people experience gas and bloating when consuming synbiotics. Those who experience these side effects may want to select a supplement that does not contain prebiotics (40).

SUMMARY

Probiotic supplements can contain allergens, lactose or prebiotic fibers that may cause adverse reactions in some people. These ingredients can be avoided by reading labels.

5. They Can Increase Infection Risk for Some

Probiotics are safe for the vast majority of the population, but may not be the best fit for everyone.

In rare cases, the bacteria or yeasts found in probiotics can enter the bloodstream and cause infections in susceptible individuals (41, 42, 43, 44).

Those at greatest risk for infection from probiotics include people with suppressed immune systems, prolonged hospitalizations, venous catheters or those who have undergone recent surgeries (45, 46, 47).

However, the risk of developing an infection is very low, and no serious infections have been reported in clinical studies of the general population.

It is estimated that only about one in one million people who take probiotics containing Lactobacilli bacteria will develop an infection. The risk is even smaller for yeast-based probiotics, with only about one in 5.6 million users getting infected (48, 49).

When infections do occur, they typically respond well to traditional antibiotics or antifungals. However, in rare cases, deaths have occurred (48, 50).

Research also suggests that people with severe acute pancreatitis should not take probiotics, as this may increase the risk of death (51).

SUMMARY

People with compromised immune systems, venous catheters, recent surgery, acute pancreatitis or prolonged hospitalizations should avoid taking probiotics.

The Bottom Line

Probiotics are living microorganisms that provide health benefits when consumed in large quantities. They can be taken as supplements, but also occur naturally in fermented foods.

Probiotics are safe for the majority of the population, but side effects can occur. The most common side effects are a temporary increase in gas, bloating, constipation and thirst.

Some people can also react poorly to ingredients used in probiotic supplements or to naturally occurring amines in probiotic foods. If this occurs, stop using probiotics.

In rare cases, people with compromised immune systems, prolonged hospitalizations or recent surgeries may develop an infection from probiotic bacteria. People with these conditions should weigh the risks and benefits before consuming probiotics.

Overall, probiotics are a beneficial addition to most people’s diet or supplement regimen, with relatively few and unlikely side effects.

Share This Post