头发是健康的征兆.doc

头发是健康的征兆A healthy head of hair is easy to spot. Its full, shiny and lustrous with no flakes, frizzies or other visible damage. But what about when your crowning glory isnt quite so glorious? In some cases, it might be a harbinger of health problemsor it could simply mean that youre spending too much time with the blow dryer.White overnight?Weve all heard horror stories of someone who, in the aftermath of some terribly traumatic event, woke up to find their formerly brown, red or blond hair turned shockingly white. Well, dont worry about it happening to you, because, according to Dr. Arielle Kauvar, a New York dermatologist, it simply cant happen. “The only way for hair to turn gray is a gradual decline in melanin production at the root,” says Kauvar. “There is no biological event that can remove pigment directly from the hair shaft.” However, a physical or emotional trauma can cause a change in the hair. The illness or stress sends actively growing hair into a resting phase, and a couple of months later, all those strands in the resting phase may fall out. So, if the dark hairs fall out and the already white ones remain, the result is hair that looks suddenly grayer.Going graySome people start finding those wiry gray strands as early as their 20s, while others hold onto their natural color well into their 40s. The cause is unrelated to how healthyor unhealthyyou are. As with so many things, it turns out you can blame (or thank) your parents for the rate at which your hair turns gray. “Its mostly genetic,” Kauvar says, “so if your parents grayed early, it is likely you will too.” The hair thats already on your head doesnt lose pigment. But as you age, there is a decrease in melanin production in the hair bulb (or root). So when new strands start to grow, they may come in with lessor nopigment, thanks to that decrease in melanin. The change happens most quickly in Caucasians, 50 percent of whom will be at least 50 percent gray by age 50.Serious sheddingSeeing a swarm of strands in the shower drain every morning isnt necessarily a cause for alarmor a signal that anything is wrong with you. Its totally normal to lose about 100 strands of hair every day. And even if you think youre losing more than that, remember that your head carries at least 100,000 hair follicles, so its possible to collect a handful or two out of the bath or hairbrush without it visibly changing the appearance of your mane. And since those 100,000 or so follicles have different growth phases, even as several strands fall out, dozens of new ones are just on their way in to replace them. So unless youre starting to notice visible thinning of your hair or bald spots on your scalp, chances are the loss is nothing more than natural, everyday shedding.Visibly thinningIf you have iron or protein deficiencycommon with the caloric deprivation of anyone suffering from an eating disorderit is not unusual to experience severe hair loss. Thats because the malnutrition forces the body to conserve protein (the building block of all the bodys cells, including the hair) by shutting down hair growth. And since more hair may also be shedwithout being replacedthe result can be a noticeable thinning over several months. Thyroid disease (both an overactive thyroid and an underactive one) can also show up as increased hair loss. Once the disease is controlled, hair growth can usually be restored.Going baldReally losing your hair can be a sign that youve inherited a tendency for baldness, or it could indicate a bigger health issue. Heredity baldness, medically known as androgenetic alopecia, affects up to one third of men. The hair losswhich typically begins at the temples or crownis permanent. Alopecia areata is an autoimmune disease which can cause anything from smooth bald patches to the loss of all hair on both the head and body. The cause of the disease isnt known, although some doctors feel there is a genetic link. With this type of alopecia, hair normally grows back.The flaky stuffDandruff is one of hairs most misunderstood maladies. People often assume that those flakes must mean that the scalp is too dry and that, like skin thats flaking, it must obviously need more moisture to make it look better. But while some people may indeed suffer from a dry scalp, true dandruff is not a matter of dryness. “Dandruff is the common name for seborrheic dermatitis, an inflammatory condition of the scalp that causes redness and flaking in the areas of the skin that are rich in oil glands,” Kauvar explains. Other skin conditionssuch as psoriasis and eczemacan also cause a similar condition in which the scalp gets red, itchy and produces flakes of dandruff. In any case, the best cure is to seek out a medicated (not necessarily moisturizing) shampoo or scalp treatment.Dull, dry, brittle, and breakingHair that looks frazzled, frizzy and fried most likely is just that. We can do tremendous damage by using chemical dyes and permanents as well as by simply aiming the blow dryer at our heads every morning. Like being in the sun, all of these self-inflicted abuses destroy the cuticle and leave hair wide open to damage. Pulling hair into tight braids or ponytails can increase that stress and lead to breakageor even bald spots. But in addition to being a cue that you need to treat you hair more carefully, unhealthy strands can also be an indicator of an unhealthy diet. Without adequate protein, growing hair strands wont become as strong and resilient as they should be. And essential fatty acids (found in fish oil supplements, wild salmon, and flax seeds) may also play a role in keeping strands strong, shiny and healthy. If your diet is lacking in them, try increasing your consumption and see if your hair eats it up! Of course, what you eat can only impact hair that is just starting to grow, so it will be several months before any improvements are evident.一头健康的头发有如下特征：丰满、光泽，没有头屑或其它可见损伤。那么，是什么使你的至高无上的头发不再那么健康呢？从某种意义上说，它可能是你身体某部健康出了问题的先兆，当然也可能是你头发吹得太多了。一夜白发我们可能都听说过一夜白发的故事：某人在经历了可怕的外伤后，一夜醒来突然发现他原本乌黑、或棕褐或红或金色的头发变白了。那么，是否出了什么问题呢？据Arielle Kauvar博士，纽约一个著名的皮肤科医生说，它可能很简单，什么也没发生。Kauvar说，头发变白的唯一原因是根部黑色素的逐步减少，而一夜变白并没有黑色素的转移等生理事件发生。当然， 一个人身体或情绪上的伤害也能导致头发的变化，疾病或压力会令头发由长到不长，数月后，那些头发可能会脱落。所以，如果头发开始脱落，白的还是那么多，那么应该引起重视了。颜色灰白当一些人年近40，头发还能保持自然光泽时，另一些人却发现他们的头发20多岁时一个样。这和一个人和身体健康与否没有必然联系，这和各人父母头发变灰年纪有关。Kauvar说，如果你的父母头发变灰早，那么你也会早。和你的年龄一样，头发根部的黑色素也会逐年丧失，在你生出的新发里，黑色素也不如年轻时那么多。这种变化在白种人里面尤其明显，50%的白种人在50岁上下时头发会变灰。严重的掉发每天早上发现大把大把地脱发，是身体某部位有状况的一个预警。每天掉大约100根头发是正常的。但如果你掉的更多的话，那么你的头发最少有10万个小泡，这就要注意收集一些早上掉下的头发以观察你的头发变化了。因为这些小泡都有不同的生长规律，一些头发的掉下，都会有新的头发在此生长出来。所以，除非你的头发开始明显地变少或开始出现秃点，那就可能是头发出了状况，不再如自然般健康了。明显的稀薄如果你缺铁或蛋白质（正常情形下，是由不正常的饮食所致正常热量的流失），