Humans lose up to 100 strands of hair a day, but we do have quite a lot of hair to start with.
人类每天最多会掉100根头发，但我们本来发量就很多。
There's some variation depending on hair colour but for an average adult the strand count is 100,000, so losing 100 a day is not too bad.
根据发色不同，发量也有所不同，对于普通成年人而言，发量为10万根，所以一天掉100根也没什么。
Although this is the average, people with red hair have around 80,000 strands, black or brown hair 100,000 and blondes have about 120,000.
尽管这是一般情况，红头发者发量约在8万根，黑发或棕发者在10万根，金发者约有12万根头发。
So hair used to be important for the reasons I mentioned earlier, but nowadays I'd say the main importance of hair is the fact that it is big business.
毛发一度起重要作用，此前我也已提及原因，但现在来说，头发的重要性主要体现在其（衍生的）大型产业。
Apart from the money involved in hair cutting, shaving, trimming, etc., a fortune is spent just on hair products.
除去剪发、剃须和修剪等等的费用以外，人们在美发产品上也投入了一大笔钱。
In the UK alone, consumers spend over five billion pounds each year on these.
仅仅在英国，消费者每年花费超过50亿英镑购买美发产品。
So next, I'd like to just give you a quick overview of the structure of hair.
接下来，我想给你们大概讲讲头发的结构。
As you can see, along the length of the hair, there are three main parts called the bulb, the root and the shaft.
正如你们所见，顺着头发长度不同，主要分三个部分，分别是毛囊、毛根和毛干。
A single hair is fixed at one end below the skin in the bulb. The bulb acts rather like a cap - it encloses the end of the hair in the head.
每根头发都由皮肤以下的毛囊固定住其中一端，毛囊的作用有些像一个箍，将头发紧附于头皮。
The next part of the hair is the root and this is the part of the hair which lies just beneath the skin and, in terms of hair production, is the most important.
下一部分为毛根（发根），这部分就在表皮以下，对于生发来说，起最关键作用。
This can be considered the control centre for each strand of hair and is where the glands are found.
我们可将这部分当作每根头发的控制中心，腺体也在此分布。
These produce oil which flows along the length of the hair and the health of the root determines the overall health of the strand of hair.
这些腺体分泌油脂，顺着头发流动，发根健康程度决定该根毛发的总体健康。
The last part is the shaft and this is the hair which is above the skin and is, of course, what we can see.
最后就一部分是毛干，这是皮上的毛发，也就是我们能看见的毛发。
Fortunately, this is not active, and I say "fortunately" because otherwise it would be very painful to have your hair cut!
幸运的是，这部分极不活跃。我说“幸运”，是因为若毛干很活跃，要理发就会变得非常痛苦。
And finally I'd just like to go over a few factors that impact on the overall health of hair.
最后我想讲讲影响头发整体健康的几个因素。
Like every other part of the body, our diet (that is what we eat) is extremely important to the condition of our hair.
就和身体的其它部位一样，我们的饮食（即我们吃的是什么）对于头发的状态说至关重要。
But whereas a change in your diet to, for example, eating unhealthy foods will soon be noticeable in your skin, changes to your hair will take a lot longer.
但尽管饮食的改变会明显反映于皮肤（例如吃不健康的食品），对头发的影响则需要经过较长时间才能体现。
A change in diet today could take several months to have an effect on your hair.
现在，饮食的变化要经过数月时间才会影响头发状态。
And so what is the key to healthy hair? Well, eating a balanced diet is the most important thing.
那头发健康的关键是什么呢？饮食均衡是最重要的。
There are a number of vitamins that are vital for good hair health, the main ones being vitamins C, D and E, and in a balanced diet all these vitamins should be readily available.
有好几种维生素对于健康头发都是必不可少的，主要是维生素C，D和E，均衡的饮食中应同时包含这些维生素。
If you need a boost of vitamin C, for example, one of the best things to eat are blueberries.
例如，如果你需要大量补充维生素C，最好吃点蓝莓。
For vitamin D, the best examples are fish, mushrooms and eggs and for vitamin E, nuts and seeds. Right, let's go on to...
要摄入维生素D，最好吃点鱼、蘑菇和鸡蛋，维生素E则是坚果和种子。好了，接下来…