你生來就註定要少吃某些食物

You are what you eat, or so the saying goes. But a new generation of molecular biologists is starting to give that old adage a decidedly high-tech twist.

俗話說：“吃什麼像什麼”。新一代分子生物學家正着手給這句話作一明白無誤的高科技解讀。

By combining the latest discoveries in human genetics with a deeper understanding of the hundreds of compounds found in food, investigators have begun to tease apart some of the more complex interactions between your diet and your DNA. In the process, they hope eventually to give consumers more personalized advice about what to eat and drink to stave off heart disease, cancer and other chronic conditions of aging.

結合人類遺傳學的最新發現和對食物中數百種化合物的進一步瞭解，研究者已經開始解析人們的日常飲食和DNA之間更爲複雜的相互作用。通過這一研究，他們希望最終能爲消費者提供一些更個性化的建議，即應如何健康飲食以避免和延緩心臟疾病、癌症和其他老年慢性病。

"We are trying to put more science behind the nutrition," says Jose Ordovas, a geneticist at the Friedman School of Nutrition at Tufts. "We want to finally understand why nutrients do what they do and to whom--why a low-fat diet may not work for some but works for others."

塔夫茨大學弗裏德曼營養學院的基因學家喬斯·奧多維斯說，“我們想讓飲食更科學，想徹底弄明白營養成分爲什麼起作用，對誰起作用——爲什麼低脂飲食只對一部分人有效。”

Do you drink three cups or more of coffee a day? Genetic tests can now determine whether you--like approximately 10% to 20% of the population--have a specific genetic variation that makes it harder for your body to absorb calcium in the presence of caffeine, thus increasing your rate of bone loss.

你是否每天要喝三杯以上的咖啡？現在遺傳學測試能夠確定你這樣的人——約佔人口的10%到20%——體內是否有某種基因變體，導致你的身體在有咖啡因時更難吸收鈣質，從而加速骨質流失。

Are you getting enough folic acid, found in beans, peas and fortified grains? Researchers have learned that many people have a genetic predisposition that puts them at greater risk of developing heart disease because they need more folic acid than the average person to maintain normal blood chemistry.

你是否攝取了足夠的葉酸？葉酸存在於蠶豆、豌豆和強化穀物裏。研究者們已經意識到許多人都有一種遺傳性易患病體質，使他們更易患心臟疾病，因爲他們需要比正常人攝入更多的葉酸來維持正常的血液化學作用。

Would a high-fat diet be particularly damaging to your health, given your genetic makeup? About 15% of folks are born with a form of a liver enzyme that causes their HDL, or good cholesterol, level to go down in response to dietary fat. In most people the HDL level goes up, counterbalancing some of the bad effects of dietary fat on LDL--the dangerous cholesterol.

從基因構成的角度來看，高脂飲食對你的健康造成嚴重損害嗎？大約15%的人生來就帶來某種形式的肝臟酶，這種酶在食物脂肪的作用下會導致高密度脂蛋白——或“好”膽固醇——的水平下降。而大多數人體內的高密度脂蛋白水平會上升，以部分抵消食物脂肪通過低密度脂蛋白——或有害膽固醇——所造成的不良影響。

None of those genetic variations are immediately life threatening. In fact, most of them have no apparent effect. The variants are not like the mutations most of us learned about in school--alterations that cause entire genes or series of genes to malfunction and that result in diseases like sickle-cell anemia and cystic fibrosis.

這些基因變異都不會直接危及生命。事實上，它們中的大多數變異甚至不會產生明顯的影響。這些變異不同於我們大多數人從學校裏瞭解到的基因突變——一種引起全部基因或者幾種基因機能的失常，並導致像鐮形血球貧血症和囊性纖維變性之類疾病的變化。

Instead the changes nutritional geneticists are looking for are more like normal variations in the correct spelling of a word--say, theatre or theater, depending on whether you speak the Queen's English or American. "We all have these variants in our genes," says Ray Rodriguez, a geneticist at the University of California at Davis. "And they affect how we absorb, utilize and store various nutrients."

相反，營養基因學家正在尋找的變異更像是一個單詞的不同的、但都正確的拼寫方式，例如theatre或theater，取決於你說的是英式英語還是美式英語。加利福尼亞大學戴維斯分校的基因學家雷·羅德里格斯說：“我們的基因中都有這樣的變異，它們影響着我們吸收、利用以及儲存各種營養成分的方式。”

Researchers now have a good reference guide for the 25,000 or so genes of the human genome and the more than 3 million common variants that lurk within those genes. They still need to figure out how all those genetic variables relate to health and disease.

研究者目前已詳細瞭解了人類基因組中大約25,000個基因以及潛伏在這些基因中的300多萬個常見變 異。他們還需要弄清楚所有這些基因變異是如何與健康和疾病相關聯的。

Add the fact that food is full of hundreds of bioactive compounds, each of which varies depending on where plants are grown or animals are raised, and you've got quite a lot of information to puzzle out. In the end, you'll probably find out you still need to eat your broccoli. But at least you'll have a better understanding of why.

再加上食物中含有成百上千種具有生物活性的化合物，而每種化合物又因植物產地或者動物飼養地不同而變化，那你就有大量的信息需要破解了。到最後，你也許會發現你仍需要吃西藍花，但至少更清楚地知道爲什麼要吃了。