What is SAD?

Seasonal affective disorder (SAD) is a form of depression or low mood related to the change of season, usually from summer to winter. While it is normal to 'hibernate' over the cold, dark winter months, persistent depressive symptoms may lead to major depression affecting your sleep, energy levels, relationships, job and appetite. The WHO has predicted that, by 2030, depression will contribute to the highest level of disability attributable to any physical or mental disorder worldwide.[1] Some signs of depression are:

  • Persistently low, sad, or depressed mood
  • Lost interest and pleasure in your usual activities
  • Thoughts of hopelessness and death
  • Decreased energy and tiredness
  • Probiotics may be your natural alternative solution.

The gut-brain axis

The last 15 years have seen the emergence of microbiota and its connection with the digestive system (aka the gut-brain axis). The food we eat is processed in the gut to produce microbial metabolites such as short-chain fatty acids, branched-chain amino acids, and peptidoglycans that trigger signalling pathways. [2] The microbiota and the brain communicate with each other via various routes, including the immune system, tryptophan metabolism (involved with ageing, energy homeostasis and behaviour), the vagus nerve (the main nerves of your parasympathetic nervous system) and the enteric nervous system (one of the main divisions of the autonomic nervous system).[3][4] 

How do probiotics reduce SAD?

Individuals with chronic illness and stress have been proven to have reduced levels of beneficial bacteria compared to non-depressed individuals. A systematic scientific review found many Lactobacillus and Bifidobacterium strains seem to have the most beneficial effects on mental health.[5] And although the scientific community is excited about the potential to solve our depression epidemic, we are still a while away before any conclusive statements can be made.

Here are the two proposed mechanisms of action:

  1. Serotonin: Probiotics may help to increase the production of free tryptophan, increasing serotonin (dubbed the "feel-good hormone"). This increase in serotonin may facilitate the regulation of the hypothalamic-pituitary-adrenal (HPA) axis to improve the stress response and reduce depressive symptoms.[5]
  2. Inflammation: individuals with depressive symptoms often have a compromised gastrointestinal lining or "leaky gut", where harmful endotoxins leak into the bloodstream to create a global immune and inflammatory response. Probiotics may help to repair the gut lining, reduce endotoxin distribution and reduce inflammation. The result is improved HPA axis regulation and neurotransmitter activity.[5]

What are Smidge® probiotics?

The Smidge® founders all overcame their personal set of health challenges using the power of probiotics. Their individual success is the driving force behind their small-batch production of clean, balanced formulas that contain no GMO and are gluten- and dairy free. In addition, they chose to use vegetarian capsules and are Current Good Manufacturing Practices (cGMP)-certified to ensure all products are stable and pure.

Smidge® Infant Probiotic

Children are increasingly suffering from stress and anxiety. The most common examples include: having negative thoughts about themselves, problems with friends, bullying, peer-group pressure, changing schools or moving homes.

Support your children's inner resilience with Smidge® Infant Probiotic powder – their most gentle formula. It is ideal for sensitive individuals of all ages, including those taking probiotics for the first time. Infants under the age of 2 may benefit from the strain Bifidobacterium infantis, which supports breast milk metabolism.

Smidge® Sensitive Probiotic (available in capsule and power)

There are various reasons for a sensitive gut. Gut sensitivities can arise after exposure to different allergens that trigger your immune system, a viral or bacterial infection, puberty, and hormones (especially in women during pregnancy or menopause).

The Sensitive Probiotic powder contains one extra strain (L. plantarum) and is twice the potency of the Infant Probiotic. Smidge® Sensitive Probiotic is a powerful formula suited for sensitive individuals who may have reacted to certain strains of bacteria found in other probiotic formulas. Many Smidge® customers with histamine intolerance, digestive issues, skin problems and other health conditions begin with Sensitive Probiotic Powder. It is best for ages 3+ or children between the ages of 2 and 3 who have already used the infant formula.

Smidge® Optimal Probiotic

When we struggle with SAD, whole-body inflammation increases. Histamines are molecules involved in local immune responses and are of interest in recent scientific studies regarding depression.[6][7][8][9]. Tuberomamillary neurons and a limited number of mast cells in the brain can produce high levels of histamine, resulting in neuroinflammation and exacerbate depressive symptoms.[10]

Smidge® Optimal Probiotic Capsules contain histamine-degrading species to help metabolise the excess histamines in the body, reduce histamine intolerance and reduce brain inflammation.

Smidge® Yeastbiotic

A persistent Candida outbreak can deteriorate the wall of your intestine, leading to a leaky gut. When this happens, not only does Candida penetrate the bloodstream, but toxic byproducts also release into your body. This can lead to many symptoms, including irritability, moodiness, anxiety, and depression.

Smidge® Yeastbiotic capsules feature the friendly yeast Saccharomyces boulardii, which can gently crowd out pathogenic yeast. S. boulardii is clinically proven to support people during antibiotic treatment, especially with Candida, diarrhoea and C. diff, as guided by a healthcare practitioner. And you don't have to worry about it affecting your antibiotics. Most people use this one on a short-term basis.



[1] Prevention of depression worldwide: a wake-up call

[2] Gut/brain axis and the microbiota

[3] The Microbiota-Gut-Brain Axis

[4] Microbes and the gut-brain axis

[5] The effects of probiotics on depressive symptoms in humans: a systematic review

[6] Chronic brain histamine depletion in adult mice induced depression-like behaviours and impaired sleep-wake cycle

[7] A tale of two transmitters: serotonin and histamine as in vivo biomarkers of chronic stress in mice

[8] Chronic histamine 3 receptor antagonism alleviates depression like conditions in mice via modulation of brain-derived neurotrophic factor and hypothalamus-pituitary adrenal axis

[9] The Role of Acute and Chronic Neuroinflammation in Depression: Uncovering the Relationship Between Histamine and Serotonin Transmission

[10] Histamine receptors, agonists, and antagonists in health and disease