基因營養學:DNA能改變健康和飲食習慣嗎

Just a few decades ago, our genes and what they say about us was largely a mystery. Now, with a quick swab of your mouth scientists can reveal everything from your family history to the diseases that you are susceptible to.

僅僅幾十年前，基因對於我們還如同一團迷霧般難以理解。而現在，只要用棉籤在口腔裏刮一下，你就能知道包括家族病史以及潛在疾病等一切信息。

This is all thanks to the human genome project, the biggest collaborative project aimed at better understanding the biology of our species. In the 90s, scientists from the US, UK, Japan, France, Germany, Canada and China worked together to work out the base pairs in our DNA.

這都是人類基因組計劃的功勞。這個世上最大的合作項目致力於更好地研究人類生物學。在上世紀90年代，來自美，英，日，法，德，加以及中國的科學家們合作並解密了人類DNA中的鹼基對。

Nutrigenomics services like DNAFit analyse a person's DNA and their genetic variations to give them a personalised workout and diet plan.

基因營養類服務，比如DNAFit，能分析人們的DNA及遺傳變異，以給出定製的鍛鍊與飲食計劃。

Ideal diet and vitamin and micronutrient intake; a person's carbohydrate and fat sensitivity; lactose and gluten intolerance risk; ability to recover after exercise; salt, alcohol, and caffeine sensitivity as well how prone a person is to of soft tissue injury are all measured.

理想的飲食與維生素和微量元素的攝入；對於碳水化合物與脂肪的敏感度；對乳糖及谷蛋白不耐受的風險；運動後的恢復能力；對鹽，酒精，咖啡因的敏感度甚至是否容易軟組織受損，所有這些項目都會被評估。

To piece together profiles, DNAFit test 45 gene variants in the human body. But, considering there are 10 million variants in the human body, how accurate and useful are the results?

DNAFit需要檢測人體45處基因變異來合成一份報告。但考慮到人體的基因有多達上千萬對鹼基，這份報告的準確度與適用度可靠嗎？

Commenting on whether honing in on 45 variants is enough to gain a deep understanding of what we should eat, Dr Tim Spector, Professor of Genetic Epidemiology, said: "sadly not."

對於研究45對鹼基是否足夠我們制定飲食計劃的問題，遺傳流行病學教授，蒂姆·斯佩克特博士給出的答案是"很可惜並不夠"。

"Although diet choices are often partly genetic, these gene variants are often associated with risk of allergy or disease," he says. "They explain only a small fraction of the differences between people. There are a few exceptions like for lactose intolerance, coffee drinking or alcohol or coeliac disease but basing diet recommendations on genetic tests not usually helpful."

"雖然對於飲食的選擇常常是由基因引起的，但這些基因的變異也常常會和過敏與疾病聯繫到一起，"他說道。"它們只是人與人之前不同的一小部分。雖然能給出關於乳糖不耐症，喝咖啡與酒精的量或是乳糜泄等的建議，但這份報告對於制定飲食計劃的幫助並不大。"

Instead, he points towards the gut microbiome - which varies widely between individuals - as the best way to personalise a diet.

他指出，變化更加多樣的腸道微生物羣對於定製膳食影響更大。

"Genetically testing your microbes is more valuable than testing your own genes at the present," he suggests.

他建議道："目前來說，檢測你體內的微生物一般比檢測你的基因更有用"。

Dr Turi King, Reader in Genetics and Archaeology at the University Leicester elaborates that there many be difference between populations, and that environmental factors including diet, exercise and smoking can play a larger part that our genes, for instance relating to conditions such as coronary heart disease.

萊斯特大學遺傳學與考古學的圖裏·金博士闡明，人類之間的區別有很多，其中的環境因素，包括飲食、運動及吸菸都會對我們的基因造成重大影響，比如與冠心病等病症之間產生聯繫。

"There's a lot of interactions going on and it's often not as simple and straightforward as we might hope.

"我們的基因與環境不斷在交互，這其中的影響常常比我們想象的要複雜和曲折。"

"But there is no doubt, particularly with the research that is going on, that we will be finding out more and more about what parts of our DNA are involved with diet, exercise and disease in the future."

"但毫無疑問，有了那些研究，對於哪部分DNA會關係到我們的飲食、運動與疾病，將來我們會了解得更深。"