New research reveals a potential mechanism for how coffee may reduce the risk of type 2 diabetes

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• New scientific research investigates inflammation and insulin resistance in habitual coffee drinkers to understand how coffee may reduce the risk of type 2 diabetes (T2D), mediated by inflammatory biomarkers in the body 1.
• Drinking just one additional cup of coffee per day was associated with a 4-6% lower risk of T2D among participants in two large prospective cohort studies, which was partly explained by lower levels of inflammation1. 
• Experts consider consuming up to 400mg of caffeine (3-5 cups of coffee) per day to be a moderate and safe amount for most adults. For pregnant or lactating women, caffeine intake should be reduced to 200mg per day2. 
• These results further support previous research on the association between higher habitual coffee consumption and lower T2D risk 3-9, especially amongst drinkers of filtered or espresso coffee and non-smokers1. 

Wednesday 22nd March 2023: A new study published in Clinical Nutrition and funded by the Institute for Scientific Information on Coffee (ISIC) has found that coffee consumption may help reduce the risk of type 2 diabetes (T2D), mediated by differences in inflammatory biomarkers in the body. The research assessed the underlying mechanisms by which coffee consumption may help to reduce T2D risk, and found that lower subclinical inflammation may partially explain the association.

T2D is partly considered an inflammatory disease, thus by researching coffee’s effect on inflammation biomarkers such as C-reactive protein (CRP), which increases when there is inflammation in the body, the study sought to understand the underlying mechanisms linking higher coffee consumption with a lower risk of T2D3-9.

Using data from the UK Biobank (n=145,368) and the Rotterdam Study (n=7,111), researchers confirmed that a one cup per day increase in coffee consumption was associated with a 4-6% lower risk of T2D. It also predicted further possible favourable impact such as lower insulin resistance, lower CRP, lower leptin and higher adiponectin concentrations in cohort participants. Adiponectin is a hormone that regulates glucose and lipid metabolism, which has been shown to have anti-inflammatory and insulin-sensitising effects, and leptin is a hormone that regulates food intake and energy homeostasis.

A one cup per day increase was measured against individuals’ varying daily consumption rather than a set baseline. Daily consumption within the study cohort ranged from 0 to ~6 cups of coffee per day, with findings suggesting benefits from an extra cup per day regardless whether individuals fell at the lower or higher end of that range.

Data from the UK Biobank cohort also suggested that the manner in which coffee is prepared may impact its health benefits. Filtered or espresso coffee had the strongest beneficial association with lower T2D risk and CRP concentrations, alongside being a non-smoker.

The study is authored by a team led by Dr. Trudy Voortman, PhD, Associate Professor in Nutritional Epidemiology at Erasmus University Medical Centre Rotterdam, with Dr. Carolina Ochoa-Rosales, PhD, Postdoctoral Scientist at the same institute, as primary author of the study.

Dr. Voortman commented: “Coffee is one of the most frequently consumed beverages worldwide and its potential health effects trigger significant scientific research. Previous studies have linked higher coffee consumption to lower risk of developing T2D but underlying mechanisms remained unclear. Our research shows that coffee is associated with differences in the levels of inflammation biomarkers in the body, and as we know that T2D is partly an inflammatory disease, this could be one of the mechanisms at play. These findings could also support future research into the effects of coffee on other inflammation-related chronic diseases.” 

The research complements the existing body of evidence on the association between coffee consumption and lower risk of T2D, which may contribute to the development of guidance on how nutrition and lifestyle changes support reduction strategies for non-communicable diseases like T2D.

This research study, ‘C-reactive protein partially mediates the inverse association between coffee consumption and risk of type 2 diabetes: The UK Biobank and the Rotterdam Study cohorts’ was first presented at ASN’s Nutrition 2021 Conference and at Epi-Lifestyle Scientific Sessions 2021 organised by the American Heart Association, where it was awarded the Paul Dudley White International Scholar Award 2021.