咖啡廳與健身日常

Fatty liver disease is exactly what the name suggests – a disease characterized by the build up of fat in the liver. There are two main types of fatty liver disease

脂肪肝這種疾病的症狀正好恰如其名：是一種在肝臟內囤積脂肪，進而造成肝臟阻塞的病症。一般來說，脂肪肝分為兩種：

Nonalcoholic fatty liver disease  非酒精性脂肪肝

Alcoholic fatty liver disease (also called alcoholic steatohepatitis) 酒精性脂肪肝〈亦稱為酒精性肝疾病/酒精性脂肪肝炎〉

Both types of fatty liver disease are diagnosed when fat makes up at least 10% of the liver, but the cause of the fat build up is different for each type.

上述這兩種脂肪肝疾病都是當脂肪在肝臟的比例中超過百分之10的情況下發生的，只是雖然都稱為脂肪肝，但是這兩種疾病的脂肪組成的來源是不一樣的。

The cause of alcoholic fatty liver disease is obvious. The amount of alcohol it takes to cause fatty build up in the liver, however, is not so obvious. The Liver Foundation suggests consuming no more than 14 drinks a week for men and 7 drinks a week for women. Anything more than may cause fat to build up in the liver.

造成酒精脂肪肝的病因是很明顯的，肝臟內所累積的脂肪是源自於酒精的攝取量，但這樣的說法過於籠統，到底飲用多少酒會應形成脂肪肝。根據肝臟協會〈the Liver Foundation〉的建議，成年男性一周的飲用量盡量不要超過14杯，而成年女性一周盡量不要超過7杯，只要超過這樣的攝取量，就很可能會造成肝臟內脂肪的累積，甚至會形成脂肪肝。

The treatment for alcoholic fatty liver disease is simple enough — stop drinking alcohol. Studies confirm that cessation of alcohol consumption can reverse alcoholic fatty liver disease.

治療酒精性脂肪肝其實相當簡單，只要戒掉酒精即可〈但其實對於有酒癮的人來說難了〉。這方面在研究上也顯示，戒掉酒精的確可以迴轉酒精脂肪肝。

However, the cause and treatment of nonalcoholic fatty liver disease are not as obvious. This is because many different factors (other than alcohol) can cause fat to build up in the liver.

但相對的，非酒精性脂肪肝的成因並不是那麼明顯，它的治療方式也並非那麼地容易。這是因為非酒精性脂肪肝的成因有太多種了，並非只單方面考慮酒精的攝取量的多寡而已。

The Truth About Nonalcoholic Fatty Liver Disease

關於非酒精性脂肪肝的真相

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〈註：原圖取自於原文〉

Nonalcoholic fatty liver disease affects 20-30% of adult populations in developed countries, but the mechanisms underlying its cause are incompletely understood. We can, however, take some clues from other common diseases to figure out why this happens.

在已開發國家中，有高達20至30%的人口是有罹患非酒精性脂肪肝的，但是這種疾病背後的成因到目前為止還不是很清楚。雖然，成因難解，但是我們可以做的，就是從其他相似的疾病來找到線索。

In epidemiological studies including people with type 2 diabetes, 62 to 69% of them also had nonalcoholic fatty liver disease. Another study found that 50% of patients with dyslipidemia (abnormally elevated cholesterol levels) had nonalcoholic fatty liver disease.

在罹患第二型糖尿病病患參與的流行病學研究〈epidemiological studies〉中顯示，其中有62%至69%的病患也正好有非酒精性脂肪肝。另一項研究顯示，大約有50%有著血脂異常〈dyslipidemia，膽固醇水準異常上升〉的病患也有這樣的症狀。

Obesity, metabolic syndrome, and heart disease are also closely linked with nonalcoholic fatty liver disease. In fact, the most common cause of death for nonalcoholic fatty liver disease patients is heart disease.

肥胖、代謝症候群〈metabolic syndrome〉與心臟病這三種症狀也與非酒精性脂肪肝有著密切的關連性。而事實上，非酒精性脂肪肝最常見的死因正是心臟病。

This leaves us with five conditions that are commonly associated with nonalcoholic fatty liver disease: type 2 diabetes, obesity, heart disease, dyslipidemia, and metabolic syndrome.

由這樣的推論來看，非酒精性脂肪肝最常見的情況有五種，分別為：第二型糖尿病〈type 2 diabetes〉、肥胖〈obesity〉、心臟病〈heart disease〉、血脂異常〈dyslipidemia〉

What is even more intriguing is that obesity, type 2 diabetes, heart disease, dyslipidemia, and metabolic syndrome all are intimately linked as well. This is because they can all be caused by a combination of lifestyle, genetics, and gut health issues. Scientists believe that the same is true for nonalcoholic fatty liver disease as well.

讓人覺得奇妙的是，上述這五個現象，如果仔細一想，有沒有發現都有著密切的關聯性。這是因為，上述的成因都源自於：日常的生活方式、遺傳及腸道健康問題〈gut health issues〉。科學家相信，這同樣也是非酒精性脂肪肝的症狀成因。

What Causes Nonalcoholic Fatty Liver Disease

非酒精性脂肪肝的成因是什麼？

The exact mechanisms that cause nonalcoholic fatty liver disease are not fully understood, but we do know for certain that lifestyle, genetics, and gut health issues play an important role.

造成非酒精性脂肪肝的確切機制目前還不是非常地清楚，但我們確定的是，生活方式、遺傳及腸道健康問題的影響相當地大。

1. Lifestyle — Eating Too Much and Exercising Too Little

日常生活方式：吃得太多，動得太少

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〈註：原圖源自於原文〉

Insulin resistance is a common side effect of eating too much and exercising too little, and it is one of the main reasons why fat builds up in the liver. Throughout the body, insulin resistance causes fatty acids to be released from fat cells and sugar to build up in the blood. The excess fatty acids and sugar (from the blood and the diet) enter the liver where they are converted into fat and stored.

吃得多、動得太少常見的後遺症就是胰島素抗性〈或稱為胰島素阻抗，Insulin resistance〉，而這正是脂肪積累在肝臟的主要原因之一〉。而這樣的狀況造成了脂肪酸從脂肪細胞釋放且糖會在血液中累積。過量的脂肪酸跟糖〈源自血液及飲食〉進到肝臟後，會轉換為脂肪然後在裡面做儲存。

As long as the liver, muscles, and adipose cells are resistant to insulin, sugar will continue to build up in the blood and fat will continue to build up in the liver. This vicious cycle of insulin resistance and fat accumulation in the liver is caused by eating too much and exercising too little.

只要肝臟、肌肉及脂肪細胞〈adipose cells〉對胰島素產生阻抗，糖會持續在血液中做積累且脂肪會在肝臟內持續囤積。由此來看，這樣胰島素阻抗及肝臟內脂肪囤積的惡性循環正是因為吃得多動得少的緣故。

Overfeeding on fat and sugar fills the cells up with energy to the point where they no longer respond to insulin. The liver receives the excess fat and sugar and has to store it has fat to save the body from the detrimental effects of having too much fat and sugar in the blood.

過量的脂肪跟糖會讓體內的細胞長時間充滿了能量，但也因此它們不在對胰島素有任何的反應。肝臟接收了過量的脂肪跟糖，只能將它們儲存為脂肪以防止血液中有過多的糖跟脂肪這樣對於體內的負面影響〈detrimental effects〉。

The quickest way to increase fat build up in the liver is by overfeeding on carbohydrates. Fructose, especially, will lead to the most fat accumulation in the liver. (Keep this in mind for when we go over the ideal fatty liver diet later.)

最快累積肝臟內脂肪的方式，就是攝取過多的碳水化合物。特別是果糖〈fructose〉會在肝臟內產生最大量的脂肪囤積〈把這句話先記著，我們後面會看看什麼叫做最理想的脂肪肝飲食〉

Having a sedentary lifestyle will also make your cells less sensitive to insulin. In fact, studies show that sitting for 2 hours after eating a meal can impair insulin sensitivity and increase blood sugar levels. Imagine what happens to you when the majority of your time is spent sitting and the majority of your meals consist of an overwhelming amount of carbohydrates and fat.

除了上述提及的飲食方面外，那動的方面呢？久坐不動〈sedentary lifestyle〉也可能會讓細胞對於胰島素有較低的敏感度。研究也證實，在吃完飯後直接坐在椅子上長達兩小時，是會減弱胰島素敏感度〈insulin sensitivity〉，並會增加血糖水準。想像一下，當您日常生活大部分的時間都是坐著且大多時候的飲食是含有過量碳水化合物及脂肪時，您的身體會產生什麼樣的狀況。

This is why many researchers agree that improving insulin sensitivity is a key strategy in the treatment of nonalcoholic fatty liver disease. However, there is a small subset of people who can get nonalcoholic fatty liver disease without showing any signs of insulin resistance.

這也正是為何，許多相關研究人員認同改善胰島素敏感度是治療非酒精性脂肪肝相當重要的一個環節。但，也有一部份罹患非酒精性脂肪肝的人並沒有顯示任何有關胰島素抗性的相關跡象。

2. Genetics — Gene Variants, Gender, and Ethnicity

遺傳：基因變異、性別及種族

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〈註：原圖源自於原文〉

Like many common diseases, nonalcoholic fatty liver disease is polygenic. This means that the interaction of many different gene variants can make someone more susceptible to having a fatty liver.

就像許多常見的疾病一樣，非酒精性脂肪肝是多基因性的遺傳疾病〈polygenic〉。這代表著，許多不同的基因變體的反應的相互影響是會讓一個人容易罹患脂肪肝。

One genetic variant, in particular, that is called  PNPLA3 I148M is associated with the development of nonalcoholic fatty liver disease without the presence of obesity, diabetes, dyslipidemia, or insulin resistance.

其中，特別是一種稱為PNPLA3 I148M的基因變體是與肥胖、糖尿病、血脂異常或是胰島素抗性現象的非酒精性脂肪肝的發展有關。

However, just because you have the gene does not mean you will have the disease. For example, the PNPLA3 I148M gene variant will only lead to disease progression in combination with alcohol abuse, unhealthy diet, high levels of fructose consumption, inactivity, or viral infection.

但是，你一定會懷疑，只是體內有這種基因並不會代表就一定會有著這樣的疾病嗎。這樣說是沒錯，單就PNPLA3 I148M這個基因變體來說其實只會促進疾病的進展，而這也需要搭配著酗酒、不健康的飲食、大量攝取果糖、少運動或是病毒感染才會容易發生這樣的現象。

The fact that nonalcoholic fatty liver disease has a polygenic basis also provides us with a possible explanation for why nonalcoholic liver disease tends to be found in clusters of family members. This is why it is of the utmost importance to develop healthy lifestyle habits if your parents and grandparents struggled with nonalcoholic fatty liver disease.

非酒精脂肪肝有著基因的緣故這樣的事實也對於為何這樣的症狀常見於有罹患非酒精性脂肪肝的家族當中有了合理的解釋。這是為何如果您有著正處於非酒精性脂肪肝病症的家人，養成健康的生活習慣就有著相當大的必要性了。

Other genetic factors like your gender and ethnicity impact your likelihood of developing fatty liver disease as well. Although older studies found that women were at greater risk for fatty liver disease, current studies found that it is more prevalent in men.

其他遺傳的因素像是性別跟種族等，也會影響脂肪肝疾病的發展喔。儘管在較早期的研究裡發現，女性罹患的風險較高，但是近年來的研究指出，男性罹患的比例越來越高了。

Scientists postulate that this is due to the difference in hormones and fat distribution between men and women. Men tend to store more fat near their organs, which is a type of fat that is more inflammatory. This increases the risk of many common diseases like heart disease, diabetes, and nonalcoholic fatty liver disease.Women, on the other hand, tend to accumulate fat in their hips and thighs, which is much less inflammatory.

關於性別方面，科學家假定這與性別間賀爾蒙的差異及體內脂肪分布有關。脂肪較容易儲存於男性的器官，而這類型的脂肪比較容易造成發炎。這也增加了許多常見疾病像是心臟病、糖尿病及非酒精性脂肪肝的風險。另一方面，脂肪較容易儲存在女性的臀跟大腿，這也代表著脂肪的屯積較不會讓女性產生炎症。

When it comes to ethnicity, studies have found that African Americans have the lowest risk of nonalcoholic fatty liver disease, despite having a higher risk of type 2 diabetes. Once again, this is thought to be because of the fact that they tend to store fat away from their organs.

再來看看種族的差異性，研究顯示，儘管非裔美洲人有著較高的第二型糖尿病的風險，不過他們罹患非酒精性脂肪肝的風險較低。再次證明前段所言，這樣現象被認為是因為脂肪儲存在他們體內通常是離他們的器官很遠的。

Conversely, Asians and Hispanics seem to have the highest risk of nonalcoholic fatty liver disease. Researchers think that this is because they tend to store fat near their organs more than other ethnicities.

相對地，亞洲人和西班牙裔罹患非酒精性脂肪肝的風險較大。研究人員認為，這是因為他們的體內較其他種族更傾向於儲存脂肪於靠近器官的地方。

Another important thing to mention is the effect that other genes have on the development of fatty liver disease. I am not talking about your genes. It’s time to move on to the genes in your microbiome.

除了上述所提的部分，另外不得不提的就是，還有其他的基因較容易促使非酒精性脂肪肝的形成。不過我在這裡並不是要繼續更深入地以遺傳基因的角度來看這件事情，而是該把焦點放在您體內微生物裡的基因了。

3. Gut Health Issues — Your Microbiome and Nonalcoholic Fatty Liver Disease

3.腸道的健康問題：微生物及非酒精性脂肪肝的關聯性

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〈註：原圖取自於原文〉

Your microbiome is made of 100 trillion bacteria that line your gut. The types of bacteria that flourish or perish have a substantial impact on your health, especially the health of your liver.

腸道裡的微生物是由高達100兆之多的細菌所組成的。這類型的細菌興衰〈講得好有歷史感，簡單來說是細菌的生長狀況〉，對於您的健康有著重大的影響，特別是肝臟的健康程度。

Studies done on the microbiome of obese patients found that they had a reduced abundance of a type of bacteria called Bacteroidetes and an increased abundance of another bacteria called Firmicutes. This ratio of Bacteroidetes to Firmicutes led to an increase in lipopolysaccharide absorption.

針對肥胖者體內微生物的相關研究中發現，他們體內一種稱為擬桿菌〈Bacteroidetes〉的細菌豐度降低，而厚壁菌〈Firmicutes〉的細菌豐度增加。而這樣的擬桿菌與厚壁菌的比率會導致脂多醣〈lipopolysaccharide〉吸收量的增加。

What are lipopolysaccharides? They are a component of the cellular membrane of gram-negative bacteria like Bacteroidetes. However, they aren’t as harmless as they sound.

那什麼是脂多醣？它們是擬桿菌〈如革蘭氏陰性菌〈gram-negative bacteria〉〉細胞膜的成分之一。由此來看，脂多醣並沒有像字面上看起來那樣的無害。

Lipopolysaccharides are endotoxins that trigger a potent inflammatory response in the body. This response contributes directly to insulin resistance in the liver and obesity.

脂多醣是一種在體內易促成潛在發炎反應的內毒素〈endotoxins〉。這種由脂多醣促進的發炎反應，是會直接造成肝臟的胰島素抗性以及肥胖。

Although everyone’s microbiome is unique, there seems to be a clear answer to where this obesity inducing microbiome comes from. The answer is — an obesity producing diet. More specifically, a high-sugar, high-fat diet.

雖說每個人體內的微生物組成都不太相同，不過目前已經對於這種促進肥胖的微生物的來源有了一個相當明瞭的答案。這個答案就是---易發胖的飲食方式。再講得精準點，就是高糖份高油脂的飲食。

This kind of diet reduces the diversity of the microbiome, favoring an increase in the Firmicutes-to-Bacteroidetes ratio in the gut. The result will be an obesity-causing microbiota profile that favors the development of obesity and fatty liver disease.

這類型的飲食方式會降低微生物的多樣性，會造成腸道裡的厚壁菌/擬桿菌這樣的比率增加，這樣的結果將會促進肥胖以及脂肪肝疾病的發展。

However, this isn’t the worst of it. The increase in lipopolysaccharides absorption caused by a poor diet and an obesity-causing microbiome can disrupt the liver so much that nonalcoholic fatty liver disease progresses to nonalcoholic steatohepatitis.

不過，這樣的結果還不是最糟的。糟糕的飲食方式加上致肥胖的微生物，造成脂多醣吸收量的增加，這會進而殘害肝臟，以致於非酒精性脂肪肝在這樣的情況下，會發展成非酒精性脂肪性肝炎〈nonalcoholic steatohepatitis〉

全文連結：Keto: The Best Fatty Liver Diet