A recent study indicates that consuming strong coffee before breakfast could hinder the body’s ability to regulate blood glucose, emphasising the importance of timing in caffeine intake for those concerned about blood sugar levels.
A morning coffee before breakfast may have a bigger effect on blood sugar than many people realise, according to a report published by CursorInfo that draws on recent research into caffeine, insulin sensitivity and glucose control. The key issue appears to be timing: drinking a strong coffee on an empty stomach, then eating shortly afterwards, may make the body less efficient at handling the incoming glucose.
In the experiment described in the report, British researchers gave participants about 300mg of caffeine in black coffee roughly 30 minutes before breakfast. Blood sugar rose by about 50% after the meal. That does not mean coffee is automatically harmful, but it does suggest that the body’s response can change depending on when caffeine is consumed.
Earlier research backs up the idea that caffeine can interfere with insulin sensitivity. A study in Diabetes Care in 2002 found that caffeine could reduce insulin sensitivity in humans, which can push blood sugar higher. Research in Metabolism in 2007 reached a similar conclusion, showing reduced insulin sensitivity after caffeine intake, with the effect lasting for hours. Other studies, including work published in The Journal of Physiology and Diabetes Care, have also linked caffeine and coffee with impaired glucose disposal and higher fasting glucose.
Researchers have pointed to two likely mechanisms. One is caffeine’s effect on adenosine, a chemical involved in insulin secretion and how cells respond to insulin. The other is its ability to raise stress hormones such as cortisol and adrenaline, which can increase glucose in the bloodstream. A study in The Journal of Physiology in 2005 found that caffeine’s effect on glucose handling was partly driven by adrenaline.
The practical advice is straightforward. If blood sugar control matters, it may be wiser to eat first and drink coffee afterwards, rather than starting the day with a strong caffeine hit on an empty stomach. Cutting the dose or switching to tea may also reduce the impact.
Disclaimer: This content is for informational purposes only and is not intended to be a substitute for professional medical judgment, advice, diagnosis, or treatment.
