January 31, 2025 from Medscape
Drinking black coffee may do more than just help you wake up — it could also help protect against type 2 diabetes (T2D). A new study published in The American Journal of Clinical Nutrition found that regular coffee consumption without additives is associated with a lower risk of T2D. But when sugar or artificial sweeteners are added, that benefit drops significantly.
Researchers analyzed data from over 150,000 participants in three large U.S. cohort studies, following them for more than 3.6 million person-years. Participants regularly completed food frequency questionnaires that captured their coffee habits and additive use.
Each additional daily cup of black coffee was linked to a 10% reduced risk for type 2 diabetes. When participants added sugar, that risk reduction dropped to 5%. Artificial sweeteners weakened the benefit even more, with just a 7% lower risk.
Adding cream didn’t have a statistically significant effect, but non-dairy coffee whiteners showed a trend toward reduced protection. When sugar and artificial sweeteners were used together, no significant protection was observed.
“The use of additives, especially sugar and artificial sweeteners, may counteract the potential benefits of coffee consumption on diabetes,”
the researchers wrote.
Why the Additives Matter
The study suggests that the benefits of coffee on metabolic health may be influenced by what’s added to it. Sugar and sweeteners may interfere with the mechanisms that make coffee protective, although more research is needed to fully understand how these ingredients impact blood sugar and insulin sensitivity.
Cream, by contrast, appeared to have no negative impact. Non-dairy whiteners showed some weakening of coffee’s protective effect, but the association wasn’t statistically significant.
What This Means for Your Daily Cup
These findings highlight a simple but impactful public health message: how you take your coffee may matter for more than just taste. Cutting back on added sugars and sweeteners could help preserve the potential metabolic benefits of your morning brew.
The researchers note a few limitations, including the inability to assess the impact of milk, different coffee types, or commercial sugar-laden coffee drinks. Also, since the majority of participants were White healthcare professionals, the results may not generalize to all populations.
Still, with diabetes rates on the rise, this study adds weight to existing evidence that diet — even small daily choices — plays a role in chronic disease risk.
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