Page 5 - SA Lifestyle Magazine

A Quick Lift
Coffee and tea are highly popular beverages people consume when they need a boost. Both contain caffeine, one of the world’s most commonly consumed stimulants.5 Caffeine’s effects include improving mood, increasing alertness, enhancing athletic performance, and reducing feelings of tiredness.5 However, large doses of caffeine (over 400mg per day) can lead to overarousal and feelings of tension and jitteriness.
L-theanine, an amino acid found in tea, supports cognitive function and has stress- mitigating properties. Studies have found that caffeine and L-theanine together increase alertness and cognition more effectively than either ingredient alone.6 L-Theanine also appears to dampen some of the stimulatory effects of caffeine which may help to attenuate some of the negative effects of caffeine overarousal.
That Gut Feeling
The enteric nervous system is a special division of the autonomic nervous system that operates within the gastrointestinal
tract to control digestive functions. Comprised of over 500 million neurons,
it is the most complex neural network
outside of the brain.7 The enteric nervous system is often nicknamed our “second brain” because it has the unique ability to operate somewhat independently from the brain. The gut-brain axis (GBA) creates a connection that allows back and forth communication
between the brain and gut. (Fig 1)
The microbes that live in our gut are part of the GBA, producing neurotransmitters and other chemicals that convey messages between the gut and brain.7,8 The gut produces approximately 95% of the body’s serotonin, a “feel good” neurotransmitter that plays important roles in mood, digestion, and sleep.8 Bacterial fermentation of dietary fibres and resistant starch in the gut generates short-chain fatty acids (SCFAs), which act on the GBA in various ways, like helping regulate serotonin production, that together affect emotion and cognition.9 Research has linked abnormally low levels of serotonin or SCFAs with various mood disorders.8,9
A healthy gut microbiome is diverse and contains a large number of microbes that produce compounds beneficial for our health and few that excrete harmful byproducts like
trimethylamine N-oxide (TMAO). Microbiomes are impacted by a multitude of lifestyle factors such as diet and medication. Different microbe species digest different substances,
and our diets help determine which species flourish.
Figure 1. The Gut-Brain Axis
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