Our daily circadian rhythms allow us to function optimally in a dynamic world, adjusting our biology and sleep-wake cycles to the meet demands imposed by our environment and lifestyle habits. (1)

Between 33-45% of the Australian population experience sleep disturbances. (2)
In addition to governing sleep-wake cycles, circadian clocks are integrated into all biological processes at a molecular level. Circadian rhythms are fundamental biological imperatives, which govern every aspect of health. (1,3)

When challenged by environmental stressors, dysphasic sleep patterns or unhealthy eating behaviors, circadian clocks can become misaligned, affecting not just sleep patterns, but leading to wide-ranging health conditions. (3)
​In addition to insomnia, circadian dysfunction has been associated with cardiometabolic disorders, glucose dysregulation, neuroinflammation, mood disorders and an increased risk of breast cancer. (1,3)
 
Circadian Reboot Support
Evidence-based approaches known to improve circadian health include the timing of light exposure, chrononutrition and many other factors: (1,3-5)

• Get as much natural morning light as possible and reduce light exposure during the evening
• Exercise, ideally during the day and not at night
• Define a sleep routine which includes relaxation and mindfulness
• Make time to step back from stressful situations and reduce pressure
• Reduce electronic devices and stimulating surroundings, at least 30 minutes prior to bedtime
• Chrononutrition: Concentrate food intake in the first and middle parts of the day
• Follow a whole food Mediterranean style diet, known to improve overall circadian health
• If napping, ensure it is no longer than 20 minutes and not within 6 hrs. of bedtime
• Avoid stimulants such as caffeine and things known to reduce sleep quality, such as alcohol.

 
4 Key Herbs for Healthy Sleep Patterns
Herbal medicines can be extremely beneficial in a clinical setting for improving sleep patterns and helping to reset sleep-wake cycles, which is essential for circadian health. For example:

• Californian poppy (Eschscholzia californica) supplementation helps normalise sleep patterns with no evidence of carry over effects or addiction. (6,7)
• Lavender (Lavandula angustifolia) improves sleep quality and shortens sleep onset by up to 80% in some clinical studies. (8,9)
• Passionflower (Passiflora incarnata) has been traditionally used for the treatment of insomnia, nervousness and anxiety. It works by improving melatonin production and supporting GABA activity. (7,10)
• Ziziphus (Ziziphus jujube) improves sleep quality, prolonging sleep time and increasing NREM sleep. It contains active constituents which are naturally sedative, by improving GABA-energic activity within the brain. (7)

 
Circadian rhythm dysfunction requires ongoing dietary and lifestyle support, including changing both day and nighttime habits to create new sustainable routines, which support a circadian health.
 
References:

1. Foster, R. G. (2020). Sleep, circadian rhythms and health. Interface Focus, 10(3), 20190098. doi:10.1098/rsfs.2019.0098 
2. Adams, R., Appleton, S., Taylor, A., McEvoy, D., & Antic, N. (2016). Report to the sleep health foundation 2016 sleep health survey of Australian adults. The Adelaide Institute for Sleep Health.
3. Abbott, S. M., Malkani, R., & Zee, P. C. (2018). Circadian disruption and human health: a bidirectional relationship. European Journal of Neuroscience. doi:10.1111/ejn.14298 
4. Zheng, D., Ratiner, K., & Elinav, E. (2020). Circadian Influences of Diet on the Microbiome and Immunity. Trends in Immunology. doi:10.1016/j.it.2020.04.005 
5. Zuraikat, F. M., Makarem, N., St-Onge, M.-P., Xi, H., Akkapeddi, A., & Aggarwal, B. (2020). A Mediterranean Dietary Pattern Predicts Better Sleep Quality in US Women from the American Heart Association Go Red for Women Strategically Focused Research Network. Nutrients, 12(9), 2830. doi:10.3390/nu12092830 
6. Schafer HL, Schafer W, Schneider W, Elstner EF. Sedative action of extract combination of Eschscholtzia californica and Corydalis cava. Arzneim Forsch Drug Res 1995; 45: 124-26.
7. Bruni, O., Ferini-Strambi, L., Giacomoni, E., & Pellegrino, P. (2021). Herbal Remedies and Their Possible Effect on the GABAergic System and Sleep. Nutrients, 13(2), 530. https://sci-hub.do/https://doi.org/10.3390/nu13020530
8. Kasper, S., Anghelescu, I., & Dienel, A. (2015). Efficacy of orally administered Silexan in patients with anxiety-related restlessness and disturbed sleep–A randomized, placebo-controlled trial. European neuropsychopharmacology, 25(11), 1960-1967.
9. Chen SL, Chen CH. (2015). Effects of Lavender Tea on Fatigue, Depression, and Maternal-Infant Attachment in Sleep-Disturbed Postnatal Women.Worldviews Evid Based Nurs. 12 (6):370-9.
10. Appel, K., et al. (2011). Modulation of the gamma-aminobutyric acid (GABA) system by Passiflora incarnata L. Phytother Res, 2011. 25(6): p. 838-43.

For more than 200,000 years, humans were foragers, consuming large amounts of fibrous plant material and evolving with gut microbiota which was well-adapted to utilise this ancestral diet. (1)
 
During industrialisation however, the gut microbiota was subjected to numerous insults, leading to two significant and detrimental changes:

1. A loss of diversity. Researchers confirm the compounded effects of reduced microbiota-accessible fibres, chlorinated water, antibiotics and other environmental pressures, has led to a loss of more than half the microbial diversity found in traditional populations. (2)
 
2. A microbiome and human genome miss-match. New research suggests our gut microbiota is rapidly evolving in an attempt to cope the industrialised diet. This rapid adaptation is in stark contrast to the much more slowly evolving human genome. The result is an incompatibility between adapted gut microbiota and human hosts. (1)
The combination of loss of diversity and incompatible microbiota, scientists suspect is a significant driver in the emergence of chronic conditions such as: (1,2)
 

• mood disorders
• immune dysfunction
• chronic inflammation
• obesity

 
How can we create more compatible and resilient microbial ecosystems?
 
Specific probiotics strains derived from minimally disturbed traditional communities, may hold the key. Research suggests unique strains are capable of remodelling industrialised microbiota, to become more compatible with our human genome and improve microbial diversity. (1,3)
 
In conjunction with healthy dietary changes, restoration of our gut microbiome may promise improved immune health, metabolic balance and a reduction in mood disorders. (1-4)

References:

1. Sonnenburg, J. L., & Sonnenburg, E. D. (2019). Vulnerability of the industrialized microbiota. Science, 366(6464), eaaw9255. doi:10.1126/science.aaw9255
2. Bello, M. G. D., Knight, R., Gilbert, J. A., & Blaser, M. J. (2018). Preserving microbial diversity. Science, 362(6410), 33–34. doi:10.1126/science.aau8816
3. He, B., et al. (2019). Lactobacillus reuteri Reduces the Severity of Experimental Autoimmune Encephalomyelitis in Mice by Modulating Gut Microbiota. Frontiers in immunology, 10, 385. doi:10.3389/fimmu.2019.00385
4. Laitinen, K., & Mokkala, K. (2019). Overall dietary quality relates to gut microbiota diversity and abundance. International journal of molecular sciences, 20(8), 1835. doi.org/10.3390/ijms20081835

The bi-directional connection between the gut and brain is well established, however researchers now believe the role microbiota plays in our perception, mood and behaviour has been significantly underestimated. (1)
 
Gut-brain axis interactions have been linked to changes in stress and anxiety behaviours, the sleep–wake cycle, sexual behaviour, perception of fear and loneliness, food cravings, social connection, even odour and attraction. (2,3)

Microbiota are capable of producing neuroactive molecules which strongly influence the autonomic nervous system via enteric neurons. They act by hijacking the vagus nerve, the neural axis between the gut and the brain. (1)

Evidence suggests gastrointestinal microbiota may be under selective pressure to manipulate host behaviour in order to increase their survival and fitness. (1)
 
For example, gut microbes are capable of altering our mood and feeding behaviour by: (1,3)

• Altering the dopamine-reward system, to generate cravings for foods they require, or foods that suppress their competitors.
• Changing neuropeptide signalling to induce dysphoria until we eat foods that enhance their fitness.
• During starvation, production of neurotransmitters such as GABA, reducing inhibitions, altering facial expressions and making us appear more socially attractive thereby increasing chances of finding food within the group.

 
The latest research suggests specific probiotic strains can therapeutically remodel the human gut microbiota, balancing the complex bi-directional interplay between the gut and nervous system. (4) Potential benefits of therapeutic remodelling of gut microbiota include reductions in stress and anxiety, improved mood, a stronger drive towards healthy eating patterns and improved social connection. (1,3,4)
References:
1. Alcock, J., Maley, C. C., & Aktipis, C. A. (2014). Is eating behavior manipulated by the gastrointestinal microbiota? Evolutionary pressures and potential mechanisms. Bioessays, 36(10), 940-949.
2.  Karsas, M., Lamb, G., & Green, R. J. (2018). The immunology of mind control–exploring the relationship between the microbiome and the brain-part 1. Current Allergy & Clinical Immunology, 31(2), 103-109.
3. Karsas, M., Lamb, G., & Green, R. J. (2019). The immunology of mind control: exploring the relationship between the microbiome and the brain (part II). Current Allergy & Clinical Immunology, 32(1), 50-57.
4. Martin, C. R., Osadchiy, V., Kalani, A., & Mayer, E. A. (2018). The Brain-Gut-Microbiome Axis. Cellular and Molecular Gastroenterology and Hepatology, 6(2), 133–148.