Microbiome bites March 12th: Probiotics For Anxiety and Bacteria for Eczema

Probiotics over prozac

Two very interesting studies this week:

1. Probiotics Over Prozac?

People suffering from depression were once dismissed with the phrase “it’s all in your head.” A new study published in the journal Scientific Reports suggests that such comments are not only thoughtless but also inaccurate.

Part of the problem is in your gut.

Researchers at the University of Virginia discovered that chronically stressed mice are lacking in Lactobacillus, a common probiotic. Simply adding the probiotic to their diets was enough to reverse the animals’ symptoms of anxiety and depression.

So, why does a lack of Lactobacillus cause anxiety and depression in the mice?

The researchers found that the low levels of Lactobacillus correlated with an increase in the levels of a metabolite called kynurenine in the blood. Kynurenine has previously been linked to depression, which suggests that these findings may also work in humans.

Evidence of the importance of the gut-brain axis continues to mount.

2. Let Bacteria Fight Off Eczema For You

Eczema is a form of dermatitis that affects some 18 million Americans. The most common form is known as atopic (meaning hereditary) dermatitis and it is particularly difficult to cure. A new study suggests that it may be possible to prevent and maybe treat it using beneficial bacteria already on your skin.

Human skin is covered in all kinds of bacteria, most of which cause no ills. However, Staphylococcus aureus, a common bacterium found on the skin, is known to aggravate the symptoms of atopic dermatitis.

Armed with this knowledge the researchers from UCSD swabbed the skin of 49 people with atopic dermatitis and 30 people without, to find what bacteria were there.

What they found was that those with healthy skin had greater numbers of two beneficial bacteria called Staphylococcus hominis and Staphylococcus epidermis. These bacteria make antibacterial peptides, which are a type of targeted antibiotics - they kill Staphylococcus aureus without harming other good bacteria. Common medicinal antibiotics are indiscriminate, killing good and bad bacteria.

The research team identified five volunteers who had an excess of Staphylococcus aureus on their skin, but hadn’t developed atopic dermatitis yet. They then took the two strains of good bacteria from the healthy skin and mixed it into a common moisturizer. The volunteers were instructed to apply the good bacteria moisturizer to one arm and a regular moisturizer to the other arm. By the following day three of the five had killed off most of the Staphylococcus aureus on the treatment arm and the other two it was completely gone!

The team doesn’t yet know if it will work for people who have already developed eczema, but clinical trials are under way.