The restorative powers of a cup of tea are often spoken of, but we'd always assumed it was mainly cultural rather than necessarily science based. However, a new study confirms that drinking tea can in fact have some real, provable health benefits: improving gut health, as well as helping to regulate your circadian rhythms (the body clock that controls your sleep-wake cycle).
An out-of-whack circadian rhythm, the kind that can result from irregular shift work or jet lag, can alter your metabolism, disrupt your blood sugar levels and lead to a higher risk of type 2 diabetes and obesity.
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These negative effects are, at least in part, due to the status of the bacteria in your gut, says Dr Carrie Ruxton, from the Tea Advisory Panel (opens in new tab) (who knew such a thing existed?). "Trillions of bacteria live in our gut – called the microbiota – and these can influence not only obesity levels and blood sugar control, but signals in the brain that make us feel sleepy or awake," explains Carrie.
A study (opens in new tab) published in Critical Reviews in Food Science and Nutrition found that simulated jet-lag caused changes in study subjects' gut microbiota, leading to weight gain and disrupted blood glucose levels. When a sample of gut microbiota from those jet-lagged study subjects was transplanted into non-jet-lagged study subjects, the new group's metabolism was similarly affected.
So here's the good part: "Studies show that plant compounds found naturally in tea – called polyphenols – have a striking effect on the gut microbiota, and encourage growth and activity of ‘friendly’ lactobacillus species,” says Carrie. These polyphenols can be found in a range of teas, including black tea, green tea, oolong and pu-erh.
That means that if you're struggling with the impact of sleep deprivation, drinking team can influence your body clock, and also help you avoid the longer-term negative impacts.
