it wasn't just because animals taste great,

味が美味いからではなく

it was pure necessity.

純粋に必要だったからだ

Climate change made many of the plants our ancestors relied on less available and meat bridged that gap.

主食である植物の多くが 気候変動で手に入らなくなり

From the discovery of fire at the latest, meat became a staple of the human diet.

肉が不足分を埋めた

But over the last few years eating meat has increasingly been associated with health risks like:

初めて「火」を発見してからは 肉が人類の主食となった

heart disease, certain cancers, and an early death.

だがここ数年で 心疾患・特定のガン・早死になどの

So how unhealthy is meat, really?

健康リスクと肉との関係が 徐々に指摘され始めている

In this video we'll only talk about meat.

では実際、肉はどれほど不健康なのか？

Dairy products deserve a video of their own.

動画で扱うのは肉だけだ

Biologically, we need to eat for three reasons:

乳製品は別の動画で触れる

for energy, to acquire materials to fabricate our cells,

生物学上、食事の目的は３つある

and to get special molecules that our bodies can't make themselves.

エネルギーの産生、細胞の材料集め

The energy and most of the materials come from the three macronutrients: fats, carbohydrates and proteins.

体内で合成できない 「特殊な分子」の摂取だ

Proteins are the most important resource for repairing and replenishing our cell structures.

エネルギーと大半の材料は

The special molecules are a large variety of vitamins and minerals we need to drive metabolic processes.

脂質・炭水化物・タンパク質という ３つの多量栄養素から得られる

Meat provides us with most of these things.

タンパク質は細胞の修復・補填に使われる 一番大事な栄養素である

It contains all essential amino acids our body needs and a lot of minerals like:

「特殊な分子」とは 多種多様なビタミンやミネラルのことで

iron, zinc and essential vitamins, some of which are barely found in plants like Vitamin B12.

代謝の活性化に必要だ

Only one essential nutrient is missing in most of the meat we consume: vitamin C.

肉からは栄養素の大半が補給できる

It appears in almost all plants and supports our immune system

全ての必須アミノ酸 鉄や亜鉛など多くのミネラル

as well as the development of connective tissues.

植物には無いビタミンB12などの 大事なビタミンが含まれている

After a few months without it you'd get scurvy.

肉食で不足する唯一の栄養素が ビタミンCだ

But meat has another big advantage, it's high bioavailability.

ほぼ全ての植物に含まれ 結合組織の形成や

Some of the nutrients in meat are broken down faster and available quicker than those from plants.

免疫力の強化といった働きを持つ

Spinach for example, contains more iron than meat, but it's absorbed much slower

ビタミンCがなければ 数ヶ月で壊血病になるだろう

and the body needs more energy to digest it.

メリットは他にもある 吸収されやすいということだ

Several health benefits have also been observed in communities that rely solely on meat.

肉の栄養素には 植物より早く分解・吸収されるものもある

The Inuit for example, are able to survive in extreme climate conditions thanks to a purely meat-based diet.

例えば、ほうれん草は肉より鉄分が多いが

Since they consume the whole animal including the organs, they get every single nutrient they need

吸収は緩やかで 消化に多くのエネルギーが必要だ

including vitamin C.

肉しか食べない地域では むしろ多少の健康効果が認められる

So meat itself is definitely not dangerous for us.

例えばイヌイットは、肉だけを食べて 厳しい気候を生き抜いている

But its health effects vary, depending on how its prepared and what animal it comes from.

臓器を含め、余す所なく食べるので あらゆる栄養素が摂取できる

When talking about meat in the Western world,

ビタミンCもね

we generally mean muscle tissues that have a high nutrient density,

つまり肉自体は 決して危険なものではない

but also lack some of the vitamins that make it possible to survive on meat alone.

だが加工の仕方や肉の種類で 健康への影響は変わる

The most healthy animals to eat are probably fish.

西洋で「肉」というと

Fish contains polyunsaturated fatty acids like omega-3,

普通は栄養素の詰まった筋組織を指すが

which may lower the risk of cardiovascular diseases and support anti-inflammatory immune functions.

ビタミンの欠乏もあって 筋組織だけで生きていくのは難しい

As part of a balanced diet, fish can be eaten regularly without worries.

一番健康に良いのは たぶん魚類だろう

Eating fish comes with its own bag of complications though,

魚はオメガ-３などの 多価不飽和脂肪酸を含み

like overfishing and the destruction of the oceans.

心疾患リスクの抑制効果や 抗炎症作用がある

We'll talk about that in another video.

バランスよく食べる分には 魚はどれほど食べても問題ない

A close second is the most popular meat, chicken.

一方で、魚を食べると 大量の問題も生じる

It's regarded as the meat with the fewest health risks.

乱獲や海洋汚染がその例だ

The only negative health effect of poultry is a bit controversial:

これは別の動画で話す

fat.

僅差で２番目に良いのが鶏肉だ

It's high content of saturated fats is associated with a higher cholesterol level and cardiovascular disease.

健康リスクが僅かだと考えられている

But this idea has also been criticized by a large number of scientists

諸説あるが1つだけ健康に悪いのは

arguing high cholesterol levels might be inherited and not caused by nutrition.

脂質だ

So in general, if you want meat and are concerned about your health, go for chicken.

高コレステロールや心疾患と関係のある 不飽和脂肪酸が

Things start to get problematic with high intakes of red meats like beef, veal, pork, lamb, horse and goat.

多量に含まれている

A recently published study recommends for example a maximum of 23 grams of red meat per day

だがこの見解は 多くの科学者に否定されてもいる

which is a very small steak per week.

いわくコレステロールが高いのは遺伝が原因で 食事のせいではないという

However, large-scale meta-analysis studies have shown that eating 100 grams of red meat every day

つまり肉を食べるとき健康が心配なら 大体は鶏肉を食べておけばいい

increases the risk of diabetes by 19%, of strokes by 11% and of colorectal cancer by 17%.

ところが牛・仔牛・豚・仔羊・馬・ヤギなどの レッドミートの大量摂取ではワケが違う

This sounds alarming. But before we panic, let's have a look at how these studies were conducted.

例えば最近の研究で レッドミートは1日23g未満が推奨されている

Because this brings us to the second big problem when trying to answer the question of

一週間で極小のステーキ程度だ

whether meat is unhealthy or not.

他方で、大規模メタ分析による研究では 毎日100gのレッドミート摂取で

Most studies that linked health risks to eating red meat were case-control studies.

糖尿病で19%、脳卒中で11%、大腸ガンで17%の リスク上昇が報告された

Which means taking a group of people with a disease and classifying them by their eating habits.

不安に思えるが、慌てる前に どういう研究だったか検証しよう

The more red meat they consume, the more likely they were to contract certain diseases.

肉が健康に悪いという結果には

The problem is that it's very hard to eliminate other factors.

研究デザインも影響するからだ

People who eat less meat tend to live a healthier lifestyle in general.

レッドミートと健康リスクの関係は ほとんどケースコントロール研究で調べられていた

They tend to eat more vegetables and fruit and are less likely to smoke and drink alcohol.

病気に罹った人を連れてきて 食習慣で比較する方法のことだ

Most studies try to eliminate these factors, but it's extremely hard to make definitive statements.

レッドミートが多いほど 特定疾患の罹患が認められたが

Things get worse when we look at processed meat though.

この方法の問題は 他の要素を排除しきれないことだ

Processing meat means adding certain chemicals by

総じて肉を食べない人ほど 健康的な生活を送りがちで

curing, smoking, sorting or fermenting

野菜や果物を多く摂り 喫煙や飲酒を避ける傾向にある

or in other words making it delicious.

多くの場合、そういう要素は排除されるが 完全な排除は極めて難しい

Bacon, ham, salami, sausages and hot dogs contain chemicals that are harmful for us

加工肉になると事態はより悪化する

like nitrates and nitrites that can damage the DNA in our digestive system and lead to cancer.

加工肉は化学物質が添加される

The w-h-o reviewed 800 studies over 20 years,

保存処理・燻製・選別・発酵が原因だ

and concluded that processed wheat is strongly linked to an increased risk of colorectal cancer.

「美味しくする」とも言う

Each extra 50 grams of processed meat per day increases your risk of cancer by 18 percent.

ベーコン、ハム、サラミ、ソーセージ、 ホットドッグは有害な化学物質を含む

When it comes to cancer risk, processed meat is now in the same category as plutonium,

例えばNO2やNO3は 消化過程でDNAを傷つけてガンを発生させる

asbestos and smoking.

WHOは20年間の800研究を再分析し

The w-h-o highlights that it's research is only about the question of whether or not something

加工肉と大腸ガンのリスク増加に 強い関連があると結論付けた

causes cancer and not to what extent.

加工肉の摂取が50g/日増えるごとに ガンのリスクが18%上昇する

But processed meat may also significantly increase the chance of suffering from

ガンの話になると

diabetes, strokes and coronary heart diseases.

加工肉とプルトニウム・アスベスト・タバコは 現在同じ分類に属する

It also makes a difference what sort of life our meat lived when it was still part of a living being.

何がガンの原因か調べただけで どの程度危険かは不明だと

It's common to feed large amounts of antibiotics to livestock

WHOは強調している

in order to prevent diseases which can spread antibiotic resistance.

だが加工肉も疾患リスクを大いに上昇させる

Combined, a high consumption of both red and processed meat

糖尿病、脳卒中、冠動脈疾患がその例だ

could increase your chance of premature death by up to 29%.

家畜が生前どう育てられたかも重要だ

This means if your chance of dying is at 3% this year, it's now 4%.

一般的に家畜には抗生物質が大量投与される

This might not sound like a lot but tiny percentages have a huge impact on societies of millions.

病気を防ぐためだが耐性菌も増える

They also seem harmless until they affect you.

加えて、レッドミートと加工肉の 両方を大量摂取すると

To blame meat alone for bad health would be wrong though.

早死にのリスクが29%上昇しうる

There is no evidence that the very essence of meat has any negative effect beyond it's high fat content.

つまり、今年死ぬ確率が3%なら それが4%になるということだ

And even this point is highly contentious.

たかが知れてると思うだろうが たった1%でも百万人単位で社会に影響を及ぼす

Just like with many other pleasures in life, sometimes too much of a good thing is harmful.

とはいえ悪影響が出るまでは肉は無害のようだ

Most public health agencies suggest cutting meat consumption to 500 grams a week

きっと肉だけが健康に悪いわけじゃない

while studies suggest cutting down processed meat as much as possible.

高濃度の脂肪以外に 肉の栄養素が悪影響を及ぼす証拠はないし

So if you feast on meat no more than once or twice a week, you should be good.

脂肪の悪影響でさえも諸説ある

For most people this already means a drastic change in their diets though,

何事もそうだが 良いことでもやりすぎは害になりうる

The average American consumes around almost 1600 grams of meat a week.

行政機関はレッドミートと加工肉の合計を 週500gに抑えるよう提言したが

The average German 1100 grams a week.

調査では加工肉も可能な限り 摂取を控えるべきだとしている

And many of us needs much much more.

要するに肉の日を 週１、２回に抑えるなら大丈夫だ

If you're not really sure, make a small note whenever you eat meat for a week or two.

とはいえ大半の人は 食生活の劇的な変化を要するだろう

You'll be surprised how much it really is.

平均的なアメリカ人は 週に約1600gの肉を食べる

So most people watching this video would benefit from cutting down on meat.

平均的なドイツ人なら1100gだ

Aside from health concerns,

それでもまだ満ち足りないようだが

there's still the fact that the meat industry is one of the largest contributors to climate change

肉食過多か分からないなら １、２週間の食事を記録してみよう

and has reached a scale where it's impossible to deliver millions of tons of meat

真実を知れば驚くはずだ

and still treat animals with dignity.

動画を見た人なら 肉を減らすメリットが分かるだろう

We've already discussed that in detail in another video.

健康以外のことで言うと

All in all, in moderation, meat is not unhealthy and you don't need to become vegetarian overnight

気候変動の元凶に 食肉産業が依然として挙がる

to have a real impact on your health and the planet.

何百万トンもの規模であるため

But your lifestyle choices do matter.

流通に不備があり 家畜の扱いはぞんざいだ

For yourself and for others.

詳細は別の動画ですでに検討した

The key is being open to trying something new once in a while.

概して、程々なら肉は不健康ではないし

Maybe you'll discover your new favourite dish.

健康や環境のことで思い悩んで 今すぐベジタリアンになる必要もない

Until you try you'll never know what you'll enjoy or what you're capable of.

重要なのはライフスタイルだ

Maybe after watching hours of Kurzgesagt videos, you've decided you'd like to learn how to animate.

自分と他者のためによく考えよう

Now you might not know this, but most of our team actually has a graphic design background.

扉は開かれた たまには新メニューに挑戦しよう

Learning about design principles first before we got into animation was really key to where we are today.

新しい好物が見つかるかも

There's a really great new Skillshare class on using Adobe Illustrator,

挑戦なくしては何が美味しく食せるのか 決して分からない

The software we use to create artwork by graphic designer Aaron Draplin

Kuzgesagtの動画に興味があるなら アニメの作り方を学んでみてはどうでしょう

and we can personally recommend it.

実はチームメンバーのほとんどは グラフィックデザイナーの経験者です

It's full of great tips to help understand and simplify a very complicated program.

我々が今日ここまで成長したのは 動画制作にあたってデザインの基礎を学んだからです

If you want to do more afterwards, we have three animation courses of our own on Skillshare too.

私たちも使っている"Adobe illustrator"を "Skillshare"で一緒に学びませんか？

Skillshare offers over 25,000 classes on topics

グラフィックデザイナーの Aaron Draplinが教えてくれます

like film and video editing, writing, design and technology from an array of skilled experts.

個人的にはオススメですよ

With the Premium Membership, you can access all of them for only $10 a month.

難しいプログラムも簡単に分かっちゃう 色々なコツが盛りだくさん！

And as a bonus, the first 1000 Kurzgesagt viewers to use the link in the description,

やる気がある人向けに

will get their first two months of Skillshare for free.

私たち自身が教える ３つのアニメ講座も用意しました