Early Alarm Clock Wake-ups Could Have Adverse Effects on Your Gut Health, Indicates New Research – But How?

A recent scientific study reveals a connection between inconsistent sleep schedules and the presence of potentially harmful gut bacteria.

This study, which was published in The European Journal of Nutrition and conducted by scientists from King’s College London in conjunction with ZOE, a personalized nutrition firm, presents first-of-its-kind findings that link “social jet lag” – the modification in our circadian rhythms due to varying sleep routines between workdays and days off – with dietary quality, dietary habits, inflammation, and gut microbiome makeup within a single population group.

It is well established that shift work can upset the body’s internal clock leading to problems like weight gain, cardiovascular issues, and diabetes.

Nevertheless, it’s less widely recognized that even minor inconsistencies in sleep routines, such as waking up early morning with an alarm clock on workdays compared to waking up naturally on days off for those with standard work hours, can also affect our biological rhythms.

According to Dr. Wendy Hall from King’s College London, the principal author of the study, “We know that major disruptions in sleep, such as shift work, can have a profound impact on your health. This is the first study to show that even small differences in sleep timings across the week seems to be linked to differences in gut bacterial species. Some of these associations were linked to dietary differences but our data also indicates that other, as yet unknown, factors may be involved. We need intervention trials to find out whether improving sleep time consistency can lead to beneficial changes in the gut microbiome and related health outcomes.”

The composition of microbes in our gut, known as the microbiome, can positively or negatively affect health by producing either beneficial metabolites or toxins. Certain microbial species may be indicative of an individual’s risk of enduring health issues such as diabetes, heart disease, and obesity. The diet we follow influences the microbiome, implying that we can modify the diversity of our gut microbiota.

The study involved 934 participants from the ZOE PREDICT study, the largest nutritional research project of its kind. Researchers analyzed blood, stool, and gut microbiome samples, as well as glucose levels of individuals with irregular sleep patterns compared to those with regular sleep schedules. Despite previous studies focusing on populations with obesity or diabetes, this study primarily involved healthy, lean individuals who typically received more than seven hours of sleep per night throughout the week.

The study found that a mere 90-minute difference in sleep midpoint – the time halfway between falling asleep and waking up – can lead to variations in gut microbiome composition.

Participants with social jet lag were found to have poorer overall diet quality, consumed more sugar-sweetened beverages, and ate fewer fruits and nuts. These dietary habits may directly impact the abundance of certain gut microbiota.

Among the six microbiota species that were more prevalent in the group with social jet lag, three have been associated with unfavorable health outcomes. These microbes are linked to poor diet, obesity indicators, and cardiometabolic health issues, as well as blood markers suggesting elevated inflammation and cardiovascular risk.

Kate Bermingham, PhD, from King’s College London and a senior nutrition scientist at ZOE, who is also the first author of the study, stated: “Sleep is a key pillar of health, and this research is particularly timely given the growing interest in circadian rhythms and the gut microbiome. Even a 90-minute difference in the mid-point of sleep can encourage microbiota species which have unfavourable associations with your health.”

Previous studies have associated social jetlag with weight gain, chronic diseases, and mental fatigue.

Dr. Sarah Berry, a scientist from King’s College London and the chief scientist at ZOE, concluded by stating: “Maintaining regular sleep patterns , so when we go to bed and when we wake each day, is an easily adjustable lifestyle behaviour we can all do, that may impact your health via your gut microbiome for the better.”

Source: 10.1007/s00394-023-03204-x

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