What's the Difference Between Fermented and Probiotic Foods?

In this series, Dr. Greg Miller, Ph.D., FACN, answers some common questions received from the health and wellness community.

Question: What’s the difference between fermented and probiotic foods?

Answer: Both fermented and probiotic foods are made with microorganisms. However, not all fermented foods are considered probiotics. Only probiotic foods have enough live organisms to deliver a proven health benefit when used in adequate amounts.

For example, both yogurt and cheese are fermented foods, but only yogurt with enough live and active cultures can claim to be a food with probiotics.

Here’s a closer look at the two:

Fermentation is a process in which a microorganism, typically bacteria, converts a carbohydrate, such as starch or a sugar, into an alcohol or an acid. Many commonly eaten foods, such as wine, beer, sauerkraut, yeast breads, yogurt, kefir and cheese are also made using fermentation. These foods can be described as “containing live active cultures.” Though fermented foods may contain living microorganisms after they are made, some do not, and their health benefits have not been well defined by research. Even so, fermented foods can make an interesting and important contribution to our health and diets.

For example, yogurt and cheese are both nutrient-rich fermented dairy foods that contribute to daily dietary recommendations. Healthy eating plans, which include low-fat and fat-free dairy foods are linked to reduced risk of certain chronic disease, like Type 2 diabetes among adults. Future research is needed to determine how the fermentation process itself or other components in these foods could impact health.

On the other hand, to be considered probiotic, it must meet the FAO/WHO definition: “Probiotics are live microorganisms that, when administered in adequate amounts, confer a health benefit on the host.”

Yogurt can be considered a probiotic food because the traditional cultures, or good bacteria, in yogurt, Lactobacillus bulgaricus and Streptococcus thermophilus, have been well studied for their ability to help with lactose digestion. These live cultures can help digest lactose, or milk sugar. You may have noticed that some brands of yogurt contain the “live and active culture” seal on the package, indicating that a significant amount of the good bacteria remain alive after the fermentation process is complete. Use of the seal is voluntary, so some brands of yogurt may choose to not use the seal even though they may contain adequate amounts of live cultures.

If you have a question on dairy foods and health you would like me to answer in an upcoming column, please leave it in the comment section below or send me a message on Twitter @DrDairy50. Click here to read my answers to other common questions.