March 1, 2024

Medical Trend

Medical News and Medical Resources

Whether coffee hurts the kidney or not depends on genes

Whether coffee hurts the kidney or not depends on genes



JAMA: Whether coffee hurts the kidney or not depends on genes! Scientists find that people with slow caffeine metabolizers who drink more than 3 cups of coffee per day are associated with more than doubling the risk of markers of kidney damage.

After the Spring Festival holiday, how many people rely on cold coffee and tea every day to overcome the long vacation syndrome and tighten their loose, tired, and rotten nerves.


Of course, the benefits of drinking coffee and tea are not only refreshing, but also have some health benefits, such as reducing the risk of cardiovascular disease and fatty liver [1].


However, some people are not suitable for drinking coffee, and its health benefits will not increase but decrease!


Caffeine in coffee is a central nervous system stimulant.

After ingestion by the human body, more than 95% of caffeine is metabolized in the liver by cytochrome P450 1A2 enzymes (CYP1A2 enzymes for short).

Individual differences in the ability to metabolize caffeine are largely determined by CYP1A2 gene polymorphisms [2,3].


Recently, an article published in the JAMA sub-journal proposed that whether high coffee intake is related to kidney damage depends on your CYP1A2 gene.


Ahmed El-Sohemy of the University of Toronto in Canada and his colleagues followed up 604 people for up to 7.5 years, collected data and analyzed them.

The results showed that for people whose CYP1A2 gene is a slow caffeine metabolizer, compared with drinking almost no coffee, drinking more than 3 cups of coffee a day was associated with a 1.7-fold increase in the risk of proteinuria, glomerular ultrafiltration, and hypertension , 1.1 times, 1.8 times correlation .

In individuals with a fast caffeine metabolizer of the CYP1A2 gene, there was no association between coffee intake and these risks [4].


The article was recently published in the journal JAMA Network Open .


Whether coffee hurts the kidney or not depends on genes

Screenshot of paper home page


The effect of caffeine intake on renal function has been controversial. Some studies have shown that caffeine may adversely affect renal function and structure by, inter alia, stimulating glomerulosclerosis [5,6].

At the same time, there are also research results to the contrary, showing that drinking moderately more coffee is associated with a lower risk of chronic kidney disease [7].


However, these studies did not take into account differences in the caffeine metabolizing capacity of different populations . Here, Ahmed El-Sohemy et al. assessed whether genetic heterogeneity in the CYP1A2 gene affects the association between coffee intake and renal impairment.


A total of 604 participants from the Italian HARVEST cohort [8] were included in the study, who were stage I hypertensive patients who had not received treatment.

 The researchers obtained genetic test results, lifestyle questionnaire results, and urinalysis data from these participants for analysis, and followed them up for a median of 7.5 years.

Proteinuria and glomerular ultrafiltration were used as indicators of renal injury. Proteinuria was defined as an albumin level ≥ 30 mg/24h, and glomerular ultrafiltration was defined as a glomerular filtration rate ≥ 150 mL/min/1.73 m 2 .


The participants had an average age of 33.3 years and an average body mass index (BMI) of 25.4. Among them, if 1 cup of coffee is calculated as 100mg of Italian espresso, 26.2% of people have low coffee intake (<1 cup/day), and 62.7% of people have moderate coffee intake (1-3 cups/day) , 11.1% of people had high coffee intake (>3 cups/day).


From the perspective of the participants as a whole, no harm was observed in drinking more coffee. But when stratified by genotype, the seemingly innocuous coffee slipped through the cracks.


According to the results of genetic testing, among these participants, more than half of the rs762551 loci on the human CYP1A2 gene were AC or CC genotypes (40.8% and 16.1%, respectively), which indicated weak caffeine metabolism [9]; The remaining 43.1% of the rs762551 loci were of the AA genotype, that is, they had a strong ability to metabolize coffee [9].


After multivariate adjustment, it was found that among participants with slow caffeine metabolism, heavy coffee consumption (>3 cups/day) was associated with proteinuria, glomerular ultrasonography, and 174%, 111%, and 181% increased risk of diabetes and hypertension (HR 2.74, 95%CI 1.63-4.62, P<0.001) (HR 2.11, 95%CI 1.17-3.80, P<0.01) ( HR 2.81, 95%CI 1.51-5.23, P<0.001) .


In participants with fast caffeine metabolism, no significant association was observed between coffee intake and the risk of proteinuria, glomerular ultrafiltration, or hypertension .


Whether coffee hurts the kidney or not depends on genes

High coffee intake was associated with an increased risk of proteinuria in individuals with AC or CC phenotypes; AA phenotypes were not


Whether coffee hurts the kidney or not depends on genes

High coffee intake was associated with increased risk of glomerular ultrafiltration in individuals with AC or CC phenotypes; AA phenotypes were not


It is worth noting that, in addition to kidney injury and hypertension, previous studies have revealed that the relationship between coffee drinking and the risk of myocardial infarction and impaired fasting blood sugar is also affected by CYP1A2 genetic heterogeneity .

All in all, these research results suggest that the health benefits and harms of drinking coffee are not applicable to everyone, and are linked to each person’s CYP1A2 gene .


However, Qidian noticed that among the 600 or so people recruited by Ahmed El-Sohemy this time, more than half of them belonged to the kind with slow caffeine metabolism and suffering from excessive drinking…Forget it, we don’t care about ourselves Are you the chosen one? I really want to show off my little coffee every day—you should be sober!










[1] N Engl J Med 2020; 383:369-378.DOI: 10.1056/NEJMra1816604

[2]Sachse C, Brockmöller J, Bauer S, Roots I. Functional significance of a C→A polymorphism in intron 1 of the cytochrome P450 CYP1A2 gene tested with caffeine. Br J Clin Pharmacol. 1999;47(4):445-449. doi:10.1046/j.1365- 2125.1999.00898.x

[3]Julious SA. Sample size of 12 per group rule of thumb for a pilot study. Pharm Stat. 2005;4(4):287-291.


[5]Palatini P. Glomerular hyperfiltration: a marker of early renal damage in pre-diabetes and pre-hypertension.Nephrol Dial Transplant. 2012;27(5):1708-1714. doi:10.1093/ndt/gfs037

[6]Singh VP, Singh N, Jaggi AS. A review on renal toxicity profile of common abusive drugs. Korean J Physiol Pharmacol. 2013;17(4):347-357. doi:10.4196/kjpp.2013.17.4.347

[7] Wijarnpreecha K, et al. Association of coffee consumption and chronic kidney disease: a meta-analysis. Int J Clin Pract. 2017;71(1):e12919. doi:10.1111/ijcp.


[8] Palatini P, Mormino P, Canali C, et al. Factors affecting ambulatory blood pressure reproducibility. results of the HARVEST trial. Hypertension and Ambulatory Recording Venetia Study. Hypertension. 1994;23(2):211-216. doi:10. 1161/01.hyp.23.2.211

[9] Cornelis MC, Kacprowski T, Menni C, et al; Swiss Kidney Project on Genes in Hypertension (SKIPOGH) Team. Genome-wide association study of caffeine metabolites provides new insights to caffeine metabolism and dietary caffeine-consumption behavior. Hum Mol Genet. 2016;25(24):5472-5482. doi:10.1093/hmg/ddw334

Whether coffee hurts the kidney or not depends on genes

(source:internet, reference only)

Disclaimer of

Important Note: The information provided is for informational purposes only and should not be considered as medical advice.