驚人! 每人每年吃土3.6萬毫克!

We all know we shouldn't eat dirt, but we do it anyway. Mostly not on purpose – dirt gets into our bodies all day, every day, whether we want it to or not. It's understandably difficult to figure out exactly how much is getting in, but that might be beside the point.

我們都知道不該吃灰塵，但總會吃到。大多數時候都不是故意的——不管我們想不想，灰塵每天都從早到晚地進入我們體內。可以理解，想要準確計算我們每天吸入多少灰塵是很難的，但這並不重要。

We get our daily dirt allowance in all kinds of ways, from contaminated food, dust inhalation, and from not washing our hands before eating. The Environmental Protection Agency (EPA) has compiled an enormous amount of research on dirt consumption. About 45 percent of the stuff we inhale or inadvertently eat is soil, and 55 percent is dust.

我們每天以各種方式吸入灰塵，通過髒的食物、吸入的塵土、還可能是因爲吃東西之前沒洗手。環境保護署彙集了大量關於吸入灰塵的研究，我們吸入或無意間吃下去的大約45%是土，55%是灰塵。

The EPA numbers on unintentional dirt consumption focus on children, with one study reporting that babies from 6 weeks to 1 year old generally get 60 milligrams a day. From ages 1 to 20, that amount goes up to 100 milligrams a day. If you take those daily numbers and make them annual, that would be 36,500 milligrams or 1.3 ounces per year.

環境保護署關於無意間吸入灰塵的數據主要關注的是兒童。根據其中一項研究報告，6周到1歲的嬰兒通常一天會吸入60毫克灰塵。從1歲到20歲，會增加到每天100毫克。如果以年爲單位換算，就是每年36500毫克或1.3盎司。

Kids, as we all know, just love eating dirt, especially between the ages of 1 and 3. One researcher theorized that although childhood dirt-eating certainly is based in curiosity about the world and the new ability to play and grab, it could also be an effort to get some vitamins and minerals. Purposeful dirt-eating usually happens around a year old, which is when many babies stop breastfeeding, so maybe they're trying to regain some of that nutrition.

衆所周知，孩子就喜歡吃灰塵，尤其是1-3歲的孩子。一個研究人員系統地指出，雖然兒童時期吃灰塵絕對是出於對世界的好奇，孩子也在鍛鍊玩和抓的新能力，但這種行爲也能使孩子吸收一些維生素和礦物質。有意識地吃土通常發生在一歲左右，這時很多孩子斷了母乳，他們可能是在努力攝取一些母乳中的營養。

However, some people keep eating dirt after early childhood, a condition called geophagy, or soil pica (pica is the habit of eating nonfood items). In American culture, geophagy is regarded with concern. Pica, in fact, is a recognized Disease by the U.S. Agency for Toxic Substances and Disease Registry, with intentional dirt consumption of 500 milligrams a day qualifying as "pathological". But historically, and in many other cultures, it's not so odd or abnormal to eat dirt. Some pregnant women in sub-Saharan Africa eat dirt to soothe stomach upsets during morning sickness or to add extra nutrients to the developing fetus' body.

然而一些人過了幼兒期還會吃土，這種情況被稱爲食土癖或土壤異食癖（異食癖就是吃非食物東西的習慣）。在美國文化中，食土癖使人們很擔心。其實異食癖是被美國有毒物質和疾病登記處認定的一種疾病，每天有意識地吃掉500毫克土就被認定爲“病態”。但從歷史上看，在很多其他文化中吃土沒那麼怪，也不算病態。一些撒哈拉以南非洲的孕期婦女吃土來緩解晨吐時腸胃不適或補充胎兒生長所需的額外營養。

So while there's definitely cause for concern about contaminated food and soil, maybe we don't need to worry so much about inadvertent dirt consumption. It's only natural, right?

所以，雖然我們絕對有理由去擔心臟的食物和土，但無意間吃的土可能真沒必要太過擔憂。這只是自然狀況，對吧？