Peanut allergies.

花生過敏。

Between 1997 and 2008, the number of American children with a peanut allergy has tripled.

在 1997 和 2008 年間，對花生過敏的美國兒童人數增為三倍。

And today, an estimated 1.8 million kids in the U.S. have one.

而現今，估計有 180 萬美國兒童對花生過敏。

That's larger than the entire population of Philadelphia.

這人數比整個費城的人口還要多。

And the U.S. is not alone.

美國並不是單一個案。

The UK, Canada, and Australia have seen a similar rise in child peanut allergies.

在英國、加拿大和澳洲，對花生過敏的兒童人數也出現類似成長。

But, that's not the case for other countries like China, Thailand, Korea, the Philippines, and Israel.

但是中國、泰國、韓國、菲律賓和以色列等其他國家的情況並非如此。

So, what do these countries have that the U.S. doesn't?

所以這些國家有著什麼美國沒有的秘密呢？

In Israel, there is a joke that the first three words out of every toddler's mouth are: abba, which means dad, ima, which means mom, and Bamba.

在以色列有個笑話，每個牙牙學語的幼童最先說出口的前三個字是：abba 表示爸爸，ima 表示媽媽和 Bamba。

Bamba is a popular peanuty snack.

Bamba 是一種受歡迎的花生類零食。

An estimated 90% of Israeli families buy it on a regular basis.

根據估計，百分之九十的以色列家庭定期購買這項商品。

And guess what?

而你知道嗎？

The peanut allergy rate in Israel is 1/10 the rate that it is in the UK.

在以色列對花生過敏的比率是英國的十分之一。

And in China and Thailand, many children eat peanut rice porridge for breakfast.

而在中國和泰國，很多小孩吃花生米粥當作早餐。

And wouldn't you know it?

你應該猜的到吧？

Peanut allergies are relatively low there too.

在那裡，人們對花生過敏的機率也相對比較低。

But this could be a coincidence, right?

但這有可能只是巧合，對吧？

Thank goodness we have the researchers at King's College London.

值得慶幸的是我們有倫敦國王學院的研究員。

They recruited 640 infants 4 to 10 months old who were at risk of developing a peanut allergy.

他們招募了 640 名四到十個月大、具有花生過敏風險的嬰兒。

Half of the kids in the study ate peanut snacks regularly.

研究中，一半的孩子經常性的食用花生類零食。

Whereas the other half were told to avoid peanuts entirely.

而另一半則被告知要完全避免食用花生。

Then when the kids were 5 years old, they were brought in for one final experiment.

然後當孩子們五歲時，他們被帶回來做最後一次實驗。

All of them were instructed to eat some type of peanut protein.

所以有人被要求食用某種花生蛋白。

Of the kids who ate peanut snacks regularly since infancy, 3.2% had developed a peanut allergy.

嬰兒時期開始經常性食用花生零食的孩子中，有百分之三點二的人對花生過敏。

But the kids who avoided peanuts altogether, were much worse off.

但完全不吃花生的孩子們情況更糟糕。

More than 17% of them had developed an allergy to a nut that they had never consumed.

超過百分之十七的孩子對他們從未食用過的堅果類產生過敏反應。

That means they were six times more likely to develop a peanut allergy than kids who regularly ate peanuts.

這說明他們對花生過敏的可能性是經常性食用花生孩子們的六倍。

Of course, this is just one study.

當然，這只是一項研究而已。

But if you know how allergies work, it begins to make sense.

但如果你知道過敏反應的運作機制，那麼它就變得很合理了。

When someone with a peanut allergy encounters a peanut for the first time, their immune system kicks into overdrive.

當有花生過敏的人吃到花生，他們的免疫系統將會加速運作。

In this case, it sees the peanut as a threat.

在這個情況中，免疫系統將花生視為一個威脅。

And it produces antibodies in anticipation for a future encounter.

並產生抗體來預防下次的威脅。

So the next time this person eats a peanut, antibodies activate an immune response which the person experiences as an allergic reaction.

所以下次當這個人吃到花生時，抗體會激活免疫反應，這種反應就是過敏。

Scientists aren't sure why some people experience reactions and others don't.

科學家不確定為什麼有些人會經歷這些反應而有些人卻不會。

But they think that early exposure can certainly help at risk infants.

但他們認為早期食用花生能夠幫助具有花生過敏風險的嬰兒。

And luckily, allergies aren't always set in stone.

而且很幸運的是，過敏並不是無法扭轉的。

In a clinical trial earlier this year, doctors recruited children with peanut allergies.

在今年稍早的臨床試驗中，醫生召集了對花生過敏的孩子。

They gave them a small dose of peanut powder and slowly increased the dose over time.

醫生給他們小劑量的花生粉並隨時間逐漸增加劑量。

Sure enough, the children's immune systems became accustomed to the powder and nearly all of them were able to build up a tolerance to it.

果然，孩子們的免疫系統已經習慣了這種粉末，且幾乎每個人都可以建立起對於花生的耐受力。

This process, called desensitization, is a way of tricking your immune system.

這個過程稱為「系統脫敏法」，是一種欺騙免疫系統的方式。

And it could, if used correctly and safely, become a way to treat children who have a mild reaction to peanuts.

如果正確安全地使用，對花生有輕微反應的兒童而言，它可以作為一種治療方法。

And although results have been promising so far, these treatments are not a cure.

儘管這些結果至今看起來很有希望，但這些治療方法卻無法真正治癒。

What's more, scientists suspect that genetics may also play a role in allergy development.

再者，科學家懷疑遺傳也可能在過敏反應的發展中扮演重要角色。

So, before you take matters into your own hands and start feeding your babies peanuts, talk to a doctor and make sure that you're in the clear.

因此，在你開始動手餵食嬰孩花生之前，請先諮詢醫生且確認自己真正了解狀況。

After all, like everything in life, peanuts should be enjoyed in moderation.

終究像生活中的每樣東西，花生應該適度享用就好。