Emerging Research: What Can Make Probiotics in Yogurt Most Effective?

Probiotics are live micro-organisms that can be beneficial to your health. In order for probiotics to be effective, though, they must be eaten in the correct amount and in a way that allows them to survive the harsh environment of the stomach.

Yogurt is considered a probiotic food because of the standard bacteria used to make yogurt, Lactobacillus bulgaricus and Streptococcus thermophilus, which help digest lactose (milk sugar). This means nutrient-rich foods like yogurt are a great way to consume probiotics!

New research is underway looking not only at which probiotic strain is added to yogurt, but whether the structure and composition of yogurt itself might uniquely interact with the probiotic to make it more effective than other probiotic vehicles.

For example, a randomized, crossover clinical trial in healthy young adults investigated the effects of adding the probiotic Bifidobacterium animalis subspecies lactis BB-12 to a yogurt smoothie. It tested the effectiveness of the probiotic and the yogurt itself vs. a supplement and evaluated the effect of adding the probiotic either before or after fermentation.

This study is the first to discover the effectiveness of this particular probiotic in humans when the probiotic was added to yogurt as well as the difference between it being eaten in yogurt or as a pill.

The effect of the probiotic on the immune system was related to how it was eaten and when it was added to yogurt:

• When the probiotic was added to yogurt after fermentation, it reduced some markers of inflammation.
• There was no effect on inflammatory markers when the probiotic was given as a supplement.
• There was no effect on specific immune cells (i.e., T-cells, Natural Killer Cells) when the probiotic was added to the yogurt prior to fermentation.

Also, data from this same randomized crossover trial documented the effect of the same strain of probiotic (Bifidobacterium animalis subspecies lactis BB-12) on the self-reported incidence and severity of a cold or flu over the course of one month in 30 young healthy adults. None of the treatments impacted incidence of cold/flu, number of episodes of cold/flu, number of days absent from work due to illness, or sick score related to cold/flu. An isolated finding was participants experienced significantly fewer days with cold and flu symptoms when they ate the yogurt smoothie alone, when the probiotic was added to the smoothie before fermentation and when it was taken as a supplement. Contrary to the results described above, these observations did not occur when the probiotic was added to the yogurt smoothie after fermentation.

The differences in results likely reflect the complexity of the immune system and how foods and probiotics influence immune pathways differently. Though mechanisms were not identified, it is worth noting that, in the second paper, yogurt alone had an effect on the immune system and a trend for cold and flu symptoms in these young adults, perhaps due to its rich content of nutrients and bioactive components derived from fermentation. Future studies are needed to replicate these findings in a larger, more diverse group of people.