Blue Monday: the link between Depression & Gut Health

Blue Monday: the link between Depression & Gut Health

  • Gut Health

  • By Mathieu Millette, Ph. D., Mcb. A.

    It's the 3rd Monday in January which means it's officially "Blue Monday". Although not backed by any real science, it's considered to be the ‘gloomiest day of the year', and is typically a time when many of us feel particularly low. The feelings of sadness could, of course, be the combined results of the lousy weather, holiday debt, or low motivation levels. But in many cases, it may add up to the much more serious and complex reality of clinical depression, an area where recent scientific evidence is highlighting the important role of the gut microbiome (the community of microorganisms in our gut). Thus, for many people, whether facing low mood or clinical depression, it can be helpful to take a deeper look into how improving your intestinal health can impact your overall health and wellbeing.


    Gut-Brain Connection

    Although it may not seem like an obvious link, the gut and brain are highly connected to each other. In fact, the gut is often referred to as ‘the second brain’.

    A bi-directional communication system known as the ‘gut-brain axis' involves the central and enteric nervous systems, which links both the emotional and cognitive centers in the brain with peripheral intestinal functions within the gastrointestinal system.1

    The enteric nervous system (ENS) is the nervous system that runs through our digestive system and is connected to the brain via the vagus nerve. The ENS makes more neurotransmitters than the brain itself, including 90% of serotonin, which is often dubbed the “happy hormone”.

    When our behavior changes in a certain way, the brain is able to influence functions in the gut (such as motility or mucin secretion and production), along with immune functions (including the regulation of inflammatory particles known as ‘cytokines').

    Vice versa, the gut influences the brain using visceral messages.2 Recent advances in science have shown how the gut microbiome influence these interactions and that ‘dysbiosis' in the gut can lead to behavioral changes.3


    Depression & Gut Microbiome Dysbiosis

    Dysbiosis occurs when the gut microbiome, including its 100+ trillion bacteria, fall out of balance. Often caused by infection, poor nutrition, medication, dietary sensitivities, and stress, it can lead to what is known as ‘intestinal permeability'.

    Because the lining of the intestines is always permeable to a certain degree, there is a constant passage of nutrients in and waste particles out. However, as a result of dysbiosis, when the lining of the intestines becomes damaged, the intestines can become hyperpermeable or what is commonly referred to as ‘leaky'. When this happens, undesired foreign substances are allowed to pass through, entering the bloodstream, which then leads to our body to turn on the defense mechanisms that result in chronic inflammation. The result of the inflammation manifests as a series of differing symptoms, one of which includes depression.


    Healthy Microbes = Healthy Brain

    The benefits of a healthy gut microbiome show us that we have the power to heal our own bodies, at least in some capacity. Here are three ways you can take action in order to make yourself more resilient against the effects of depression:


    1. Adjust your diet: the foods you choose to eat can help to either create or reduce inflammation, which as noted above, is directly associated with the symptoms of depression. Choosing foods that contain natural probiotics (fermented foods), healthy fats (olive oil), phytonutrient rich fruits and vegetables, along with amino-acid rich bone broth can all support inflammation. Limit processed foods and decrease your intake of added sugars. Refer to your healthcare professional for more details.


    2. Take a proven probiotic: improving the quantity and variety of good gut bacteria with a potent, high-quality probiotic can support the gut microbiome diversity and help manage dysbiosis. When choosing a probiotic, it’s imperative that it contains bacterial strains that work together synergistically, and that the science shows that it is clinically proven to be effective for human health, being backed by finished product research. Take a look at Bio-K+ products that meet all of these criteria.


    3. Learn to relax: psychological stress, in particular, has profound effects on gastrointestinal function, especially when it's chronic. Learning how to rest and relax via stress reduction techniques such as deep breathing, meditation, yoga, or spending time in nature can all support a healthy nervous system and thereby also promote digestive health.


    Depression is a real problem and one with debilitating effects. However, preventing or reducing its impact isn't out of reach. Making the effort to support your gut microbiome with a high-quality probiotic such as Bio-K+, eating an anti-inflammatory diet and using stress management techniques will no doubt have positive downstream effects.


    Do you have any other questions about gut health? Ask us in comments below. If you are looking to stock up on Bio-K+, head to our store locator. For more information on Bio-K+, probiotics and digestive health, contact us, find us on Facebook and Instagram or join our community



    1. Carabotti, M., Scirocco, A., Maselli, M.A., & Severi, C. (2015). The gut-brain axis: interactions between enteric microbiota, central and enteric nervous systems. Annals of Gastroenterology.

    2. Oiach, Clara Seira et al. (2016). Food for thought: The role of nutrition in the microbiota-gut-brain axis. Clinical Nutrition Experimental, Volume 6, 25 - 38

    3. Lyte, M., Vulchanova, L., & Brown, D.R. (2010). Stress at the intestinal surface: catecholamines and mucosa–bacteria interactions. Cell and Tissue Research, 343, 23-32.

    4. Kelly, J.R., Kennedy, P.J., Cryan, J.F., Dinan, T.G., Clarke, G., & Hyland, N.P. (2015). Breaking down the barriers: the gut microbiome, intestinal permeability, and stress-related psychiatric disorders. Frontiers. Cellular. Neuroscience, 9, 392.


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    Mathieu Millette Mcb. A.
    About the author
    Graduated with honors from INRS-Armand-Frappier Institute, Dr Mathieu Millette is an authority on probiotics for the last 20 years.
    View all articles by Mathieu Millette
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