For a long time, it's been thought of primarily as a psychiatric disorder, but new research published this week in the journal "Nature Genetics" suggests there's an important physiological aspect as well.

長期以來厭食症一直都認為是精神疾病，但這週發表在《自然-遺傳學》期刊的新研究指出其中也有重要的生理因素。

This research links the disorder to genetics and metabolism, and it might change the way we understand the origins of the illness as well as potential treatments.

該研究將厭食症與遺傳及新陳代謝做連結，而這可能會改變我們對厭食症起因的了解，以及可能的治療方法。

Anorexia nervosa is an eating disorder.

神經性厭食症是種飲食障礙。

Affected people may be dangerously underweight, with a restricted intake of food, and often also have a distorted body image.

患者可能危險過瘦，對於食量受到限制，往往伴隨著身體變形。

The end result is that the body is starved of sufficient nutrients, which can lead to various medical complications and even death.

最終身體缺乏足夠的營養，導致各種併發症，甚至是死亡。

In fact, according to the U.S. National Institute of Mental Health, anorexia is the most deadly mental disorder.

事實上，根據美國國家心理衛生研究院，厭食症是最致命的精神疾病。

Even with treatment, many patients struggle to fully overcome anorexia.

就算有接受治療，很多患者仍在努力克服厭食症。

The authors of this new research suggest that current treatments might be too focused on psychology, and fail to consider the physiology involved in the disorder.

寫下這篇最新研究的作者指出，現在的治療方法可能太著重在心理上，而沒有想到這種疾病所牽扯到的生理學。

This study pulled together genetic data on almost 17,000 cases of anorexia nervosa among people of European ancestry.

這項研究匯總了歐洲血統中有神經性厭食症的遺傳數據，幾乎有 17,000 例。

When they compared that dataset with a control group, they found eight genetic variants significantly associated with anorexia.

當他們將該資料集與對照組進行比較時，發現了 8 種與厭食症明顯相關的遺傳變異。

Interestingly, some of these genetic traits are known to be related to levels of physical activity, as well as to metabolism, the processes inside the body that convert sustenance into energy.

有趣的是，這些遺傳特徵中有一些與身體活動和新陳代謝的程度有關，新陳代謝是身體內部將營養轉換為能量的過程。

People suffering from anorexia have been known to show signs of abnormal metabolism, but this has often been thought of as a side effect of being starved of nutrients.

現在已知患有厭食症的人會表現出新陳代謝不正常的跡象，但通常會認為是缺乏營養的副作用 。

However, the researchers say this genetic link means that an unusual metabolism might actually be partly responsible for causing the disorder.

然而，研究人員表示，遺傳上這樣的相關性代表不正常的新陳代謝可能是造成厭食症的部分原因。

The researchers say we should think of anorexia nervosa as arising from a combination of both psychological and physiological factors.

研究人員表示，我們應該將神經性厭食症，視為心理和生理因素的結合。

They say their analysis potentially expands the list of risk factors for the disorder, that is, characteristics that increase a person's likelihood of developing it.

他們表示，他們的分析無形中擴大了該疾病的危險因子列表，意思就是，一個人會患上此疾病的特徵。

And that in turn opens up a whole new avenue for medical professionals looking to develop treatments for this deadly disease.

因此這為想要找出治療方法來對付這種致命疾病的醫療專業人士開闢出一條全新的道路。

And anorexia isn't the only illness that's more complicated than it seems.

而厭食症不是唯一一個本身比表面看會更複雜的疾病。

Another new study this week, published in the "Journal of the American Medical Association," found a similar duality with dementia, but the other way around.

本週發表在《美國醫學會雜誌》的另一項研究發現失智症也有類似的關係，但因果是相反的。

Dementia is defined as a decline in mental ability that's severe enough to interfere with a person's daily life.

失智症定義為精神能力下降，嚴重到足以擾亂一個人的日常生活。

It can take many forms, but the most common is Alzheimer's disease, which affects more than five million people in the US alone, and Alzheimer's is known to be linked to genes.

它有很多形式，但最常見的是阿茲海默症，單在美國就有超過五百萬人受影響，而眾所周知阿茲海默症與基因有關。

There are well-known genetic risk factors that are associated with a patient's likelihood of developing Alzheimer's.

現今已知患上阿茲海默症有關的危險遺傳因子。

But this new study found that dementia can also be influenced by how healthy a person's lifestyle is.

但是這項新研究發現失智症也可能受到生活方式健康程度的影響。

Like the first study, this one looked at a wide sample of genetic data, this time from nearly 200,000 people in the UK, including more than 1,700 recorded cases of dementia.

如同第一項研究，本次也研究了廣泛的遺傳數據樣本，這次調查了近 200,000 英國人，其中包括 1,700 多例的失智症病例。

The researchers assembled a genetic risk score for each person, but also a lifestyle health score based on each person's self-reported diet, level of physical activity, and frequency of smoking or drinking alcohol.

研究人員收集每個人的遺傳風險分數，並根據每個人的自我飲食、身體活動程度，以及抽菸或喝酒的頻率來對生活方式進行健康評分。

They found that, even among people with a high genetic risk, the incidence of dementia was significantly lower in people with a healthier lifestyle versus people living less healthy.

他們發現，即使具有高遺傳風險的人，所擁有較健康的生活方式，與健康狀況較差的人相比， 失智症的發生率也明顯較低。

The difference was small but noteworthy.

差異雖然很小，但值得關注。

Of the study participants with high genetic risk of dementia, the disease developed in 1.78% of those with unhealthy habits, but only 1.13% of those with a healthier lifestyle.

有失智症高遺傳風險的研究參與者中，生活不健康的人有 1.78% 會發展成失智症， 但對於生活較健康的人只有 1.13%。

So in absolute terms, this would mean that if people at higher genetic risk improved their lifestyle, one case of dementia could be prevented for each 121 at-risk individuals every decade.

當然，這代表，如果遺傳風險高的人改善其生活方式，十年中，每 121 位高風險人， 就能預防 1 例失智症。

So this is certainly not a cure, but it does seem that dementia, like anorexia nervosa, is related to a combination of factors, both genetic and behavioral.

當然，這絕對不是解藥，但似乎失智症就像神經性厭食症，與遺傳和行為等多種因素有關。

Which is exciting because as we learn more, we might discover ways for people to offset their built-in risk of dementia by adjusting their behavior and lifestyle.

這令人興奮，因為只要我們了解更多，可能會發現透過調整行為和生活方式能夠抵銷他們固有的失智症風險。

But there's definitely still more to be learned.

但是這樣的了解肯定還不夠。

Both of these studies looked at specific populations of people, mainly those of European ancestry.

這兩項研究都針對特定人群，主要是擁有歐洲血統的人。

And it will no doubt take more study in more diverse populations to tease out exact interrelationships between the various factors involved in these diseases.

而肯定也必須在更多不同人群中進行更多研究，才能梳理出這些疾病的各種因素間確切的相互關係。

But the takeaway here is that illness is complicated, especially the ones we haven't figured out how to treat yet.

但重點是，這種疾病很複雜，尤其是我們還沒弄清楚如何治療時。

Genetics can be very helpful in understanding where diseases arise, but your genes are not your destiny.

遺傳對於了解這種病的起因非常有幫助，但遺傳不能決定你的命運。

Diseases often have complex and interrelated causes, and the more we come to understand that complexity, the better chance we have in the fight against them.

疾病通常有複雜和互相關聯的原因，我們了解越多其複雜性，就越有機會來對抗疾病。

Thanks for watching this episode of SciShow News.

感謝觀看本集 SciShow News 。如果你有興趣幫我們將每日影片讓全世界認識，從新聞到快問快答再到深入討論，你可以在 Patreon 上支持我們。 到 patreon.com/scishow 看看，那就是我們這麼做的全部原因。 感謝各位。