Coffee consumption and health: umbrella review of meta-analyses of multiple health outcomesBMJ 2018; 360 doi: https://doi.org/10.1136/bmj.k194 (Published 12 January 2018) Cite this as: BMJ 2018;360:k194
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In this review (1), the authors did the analysis to observe existing evidence for associations between coﬀee consumption and multiple health outcomes using meta-analysis, which is quite valuable in this studying area. As a conclusion, there did not exist exact connection between coﬀee consumption within usual levels of intake and disease. Interestingly, the protection effect did exist at three to four cups a day, which is more likely to benefit health than harm. Actually, the factors associated with coffee are more from chemical synthesis. In our opinion, it may be complicated and there are many confounding factors in these different articles, which is also mentioned by the authors.
Firstly, life styles vary largely according to income conditions. Income inequality was associated with higher health care expenditures (2). Thus, this of different people cannot be ignored and mixed.
Secondly, the plants (coffee beans) vary according to the types and different weather over years, seasons or situations, and the substances change (3). The influencing factors inside are different, which may contribute to different disease processes. Besides, the preferences people eat or drink are different, and some choose to add cream into coffee and some prefer sweetening. All of the differences may contribute to the bias.
Finally, the way coffee beans are baked varies, which may also contribute to the different content inside.
In this way, we speculate that at times some of the ‘non-medical factors’ may have influences on the outcomes though no changes may be observed for the disease process. Recently, more and more natural agents or extractives have been studied for disease generation (4-8). It is beneficial for patients and recovery. However, for clinic research, more details should be considered and a detailed guide may be needed to make these more standard and concise. Thus, better suggestions can be used in our clinical work.
1. Coffee consumption and health: umbrella review of meta-analyses of multiple health outcomes. Bmj. 2018 Jan 12;360:k194. PubMed PMID: 29330262. Pubmed Central PMCID: 5765813.
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5. Kim CY, Chung KS, Cheon SY, Lee JH, Park YB, An HJ. Rice Hull Extract Suppresses Benign Prostate Hyperplasia by Decreasing Inflammation and Regulating Cell Proliferation in Rats. Journal of medicinal food. 2016 Aug;19(8):746-54. PubMed PMID: 27441629.
6. Jeon HJ, Chung KS, An HJ. Anti-proliferation effects of Cistanches salsa on the progression of benign prostatic hyperplasia. Canadian journal of physiology and pharmacology. 2016 Jan;94(1):104-11. PubMed PMID: 27123496.
7. Chung KS, An HJ, Cheon SY, Kwon KR, Lee KH. Bee venom suppresses testosterone-induced benign prostatic hyperplasia by regulating the inflammatory response and apoptosis. Experimental biology and medicine. 2015 Dec;240(12):1656-63. PubMed PMID: 26085572.
8. Buncharoen W, Saenphet K, Saenphet S, Titaram C. Uvaria rufa Blume attenuates benign prostatic hyperplasia via inhibiting 5alpha-reductase and enhancing antioxidant status. Journal of ethnopharmacology. 2016 Oct 9. PubMed PMID: 27732901.
Competing interests: No competing interests