最近，一篇發表於國際雜誌International Journal of Epidemiology上的研究論文中，來自丹麥的科學家們通過研究首次利用基因來調查咖啡對機體的效應，相關研究結果表明咖啡和生活方式引發的疾病風險並無關聯。

　　我們都喜歡喝咖啡，本文研究者發現咖啡並不會增加也不會降低個體患生活方式疾病，比如肥胖、糖尿病等疾病的風險；研究人員基於機體的基因而開展的研究，因為基因決定著我們一天內攝入咖啡的量。文章中研究者共對9.3萬名丹麥人進行了研究，該研究首次調查了基因和個體一生大量攝入咖啡之間的關聯，研究者表示，咖啡本身和生活方式引發的疾病並沒有任何關係。

　　文章中研究者設計了一種獨特的研究方式，即對影響機體對咖啡欲求的基因進行了深入的剖析和研究，如果機體中存在特殊的咖啡基因，那麼想必沒有這種基因的個體而言，攜帶咖啡基因的個體攝入咖啡的量要高一些，而這就可以幫助研究者去觀察是否大量的咖啡攝入會增加或降低個體患生活方式疾病的風險。

　　最後研究者Boerge Nordestgaard說道，如今通過研究我們都知道，咖啡基因和個體患2型糖尿病或肥胖症的風險並無關聯，這就表明，喝咖啡並不會引發，同時也並不會保護個體患生活方式類的疾病，後期研究者還將通過更為深入的研究來解析為何喝咖啡和個體患生活方式的疾病並無關係。

　　doi:10.1093/ije/dyv083

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　　Coffee intake and risk of obesity, metabolic syndrome and type 2 diabetes: a Mendelian randomization study

　　Ask Tybjrg Nordestgaard1,3, Mette Thomsen1,3 and Brge Grnne Nordestgaard1,2,3,*

　　Background: Coffee is one of the most widely consumed beverages. We tested the hypothesis that genetically high coffee intake is associated with low risk of obesity, metabolic syndrome and type 2 diabetes, and with related components thereof. Methods: We included 93 179 individuals from two large general population cohorts in a Mendelian randomization study. We tested first whether high coffee intake is associated with low risk of obesity, metabolic syndrome and type 2 diabetes, and with related components thereof, in observational analyses; second, whether five genetic variants near the CYP1A1, CYP1A2 and AHR genes are associated with coffee intake; and third, whether the genetic variants are associated with obesity, metabolic syndrome and type 2 diabetes, and with related components thereof. Finally, we tested the genetic association with type 2 diabetes in a meta-analysis including up to 78 021 additional individuals from the DIAGRAM consortium. Results: Observationally, high coffee intake was associated with low risk of obesity, metabolic syndrome and type 2 diabetes. Further, high coffee intake was associated with high body mass index, waist circumference, weight, height, systolic/diastolic blood pressure, triglycerides and total cholesterol and with low high-density lipoprotein cholesterol, but not with glucose levels. In genetic analyses, 9–10 vs 0–3 coffee-intake alleles were associated with 29% higher coffee intake. However, genetically derived high coffee intake was not associated convincingly with obesity, metabolic syndrome, type 2 diabetes, body mass index, waist circumference, weight, height, systolic/diastolic blood pressure, triglycerides, total cholesterol, high-density lipoprotein cholesterol or glucose levels. Per-allele meta-analysed odds ratios for type 2 diabetes were 1.01 (0.98–1.04) for AHR rs4410790, 0.98 (0.95–1.01) for AHR rs6968865, 1.01 (0.99–1.03) for CYP1A1/2 rs2470893, 1.01 (0.98–1.03) for CYP1A1/2 rs2472297 and 0.98 (0.95–1.01) for CYP1A1 rs2472299. Conclusions: High coffee intake was associated observationally with low risk of obesity, metabolic syndrome and type 2 diabetes, and was associated observationally with related components thereof, but with no genetic evidence to support corresponding causal relationships.