Read Time:3 Minute, 28 Second

Some of the most extensive research into the human microbiome has revealed that the health or variance in genetic diversity of certain bacterial species in your gut can help, sometimes significantly, with many of the most commonly diagnosed mental disorders such as depression, anxiety, or PTSD.

This includes work from the American Gut Project, which sources out the world’s largest collection of gut microbe samples – over 11,000, for use in scientific research. American Gut Project findings, while purely observational, suggest that bacterial diversity and richness in the human gut has the capacity to improve a variety of depressive symptoms.

In a recent paper published by the journal Nutrition, Iranian scientists found that markers for depression were reduced when taking a probiotic supplement containing particular microbes called lactobacillus casei and lactobacillus acidophilus.

In the small randomized, double-blind, placebo controlled trial, 40 people with major depressive disorder, also known to the world simply as “depression,” were given an 8 week course of probiotics. Diet and exercise activity were reported and controlled for, and after the 8 weeks ended, the scores of a self-administered questionnaire were compared with those from the start of the trial.

The researchers found that patients who had received a probiotic supplement had significantly lower scores on the Beck Depression Inventory than those who had received placebo. Blood tests would also show decreased insulin levels, and insulin resistance, increased glutathione levels, and lower C-reactive protein concentration in the probiotic group.

C-reactive proteins are compounds produced in the liver in response to inflammation. High levels of C-reactive proteins could indicate anything from an infection to cancer. This is typical of inflammatory molecules in our bodies, as several have been linked with every known disease, including depression and anxiety, and low levels of inflammation have been suggested as a potential corollary of longevity in humans.

Cheese for your Brain

For years, people have been eating cheese as a digestive assistant after meals, particularly in Europe where cheese holds a more prominent place in local culture and eating habits. Europe also has far-less restrictive laws for the manufacturing and distribution of raw milk products.

L. casei and L. acidophilus are common microbes found on raw or unpasteurized cheeses and yoghurts, or pasteurized dairy products which have been cultured. In fact, researchers have hypothesized that cheese can be an easy, less-expensive, and effective way of offering probiotic supplements to the public, since many cheesemakers use L. acidophilus and L. casei as lactic-acid starters in cheese production, and because cheese is a very viable environment for these types of microbes.

In one of the two most thorough reviews of probiotic-depression literature, Roumen Milev and Caroline Wallace found that out of 7 studies that sought to establish whether probiotic supplementation or a probiotic containing food or beverage, often dairy-based, can help alleviate MDD, anxiety, and improve cognition and mood, all but 2 found that it did. Across all 10 studies analyzed, the most common probiotic strain used was L. casei.

The study acknowledged that the increased expressions of C-reactive proteins, as well as pro-inflammatory cytokines like TNF-A, IL-1B, and IL-6, are recurring motifs in patients with symptoms of a mental or anxiety disorder, and suggested this might be due to increased gut-permeability, also known as “Leaky gut syndrome”.

It is hypothesized that probiotic food and supplements improve the stomach and gut lining, reducing permeability and therefore inflammation, just as was found in the Iranian paper.

Cultured or raw cheese, milk, or yoghurt have the ability to provide a host of lactobacillus species in an environment where they can thrive and remain viable for longer. Because they are used as a starter and so often inhabit cheese, yoghurt, or kefir, cultured dairy products also provide the microbes with a readily available source of their most prefered food when they arrive in your gut – lactose and casein.

All this perhaps suggests that cheese has a place in the modern American diet – especially if it is cultured.