In the News: Omega-3s & Stress, Yogurt & the Brain

Omega-3s May Help Blunt the Effects of Stress

Stress is a normal part of life. But scientists have long known that prolonged, unmanaged stress can negatively affect one’s health. There’s a well-documented link, for example, between mental stress and heart disease, high blood pressure, chest pains or irregular heart beats.

Evidence gained over the years also indicates that omega-3 fatty acids found in fish oil help protect against cardiovascular disease, yet the underlying protective mechanisms are still not fully clear.

Could there be a connection between mental stress and omega-3s when it comes to heart heath?

Results of a new NIH-funded study (1) suggest that there is, and that these fatty acids can blunt the detrimental effects of mental stress on the cardiovascular system.

In the study, participants underwent a mental stress protocol before and after 8 weeks of taking either a placebo or fish oil supplement daily (providing 1.6 grams of EPA and 1.1 grams of DHA). The stress protocol consisted of participants doing a mental arithmetic drill as fast as they could for 5 minutes.

The fish oil supplements significantly lessened the stress-provoked increases in heart rate and muscle activity compared to placebo.

In short, the study provides new evidence that fish oil reduces the way the heart beats in reaction to mental stress, and could be one way in which the omega-3s benefit cardiovascular health.

Can We Count Yogurt as a “Brain Food”?

In keeping with the topic of the mind-body connection, another unique study2 conducted at UCLA is the first to show an interaction between probiotics (friendly bacteria) and the brain in people.

We usually associate probiotics with digestive health, but the new research provides pretty compelling evidence that probiotics can also affect brain activity.

In this study (2), women ate either a probiotic-rich yogurt, or an unfermented yogurt without probiotics twice daily for a month.

The women then underwent an MRI before and after completing an emotion-recognition task. The task entailed viewing a series of pictures of people with angry or scared faces and matching them to other faces showing the same emotion.

The MRI provided images of the brain at rest and during the reaction to the emotion-matching task.

Changes in brain activity were clearly seen only in the probiotic-consuming group.

The “at rest” images showed greater connectivity between the midbrain and the thinking associated areas of the brain’s cortex. The probiotic group also showed less brain activity during the task, suggesting that they were better able to process emotion and sensation than the placebo group.

Although they don’t yet know the signaling pathways involved, the researchers do know that signals are sent from the intestine to the brain, and that friendly bacteria living in the gut can affect those signals.

Scientists now need to figure out how the signals are sent, and how their findings can best be used to benefit people. Probiotics could, for example, help those with abnormal responses to pain and stress related to microflora imbalance.

In the meantime, there are lots of good reasons to support a healthy microflora. Probiotic rich foods include yogurt, milk with acidophilus, fermented foods like kefir, miso, sauerkraut, kimchi and soft cheeses like Gouda and cottage cheese. You can also eat sources of prebiotics (foods that feed friendly bacteria) such as the soluble fibers in fruits, vegetables (jicama, garlic and onions particularly) and whole grains. Pro-and pre-biotic supplements are helpful as well.

References

1. Carter JR et al. Fish oil and neurovascular reactivity to mental stress in humans. Am J Physiol Regul Comp Physiol 304:R523-30, 2013.
2. Tillisch K et al. Consumption of fermented milk product with probiotic modulates brain activity. Gastroenterol 144:1394-1401, 2013.