1 . “Tooth loss and gum disease, which is inflammation (发炎) of the tissue around the teeth that can cause shrinkage (萎缩) of the gums and loosening of the teeth, are very common, so evaluating a potential link with brain diseases is incredibly important. Our study found that these conditions may play a role in the health of the brain area that controls thinking and memory, giving people another reason to take better care of their teeth,” said study author Satoshi Yamaguchi, Ph.D. of Tohoku University in Sendai, Japan.

The study involved 172 people with an average age of 67 who did not have memory problems at the beginning of the study. Researchers found that the number of teeth and amount of gum disease was linked to changes in the left hippocampus of the brain. For people with mild gum disease, having fewer teeth was associated with a faster rate of brain shrinkage, which was the same for people with severe gum disease having more teeth. After adjusting for age, researchers found that for people with mild gum disease, the increase in the rate of brain shrinkage due to one less tooth was equal to nearly one year of brain aging. By contrast, for people with severe gum disease, the increase in brain shrinkage due to one more tooth was equal to 1.3 years of brain aging.

“These results highlight the importance of preserving the health of the teeth and not just maintaining the teeth,” Yamaguchi said. Though the study does not prove that gum disease or tooth loss causes diseases like Alzheimer’s, it only shows an association. Yamaguchi added, “Future studies are needed with larger groups of people.” The current experiment involved only a small group of people in one region of Japan, and that too from one particular region of the world.

2 . Taking Care of Your Eyes

Many of us don’t pay much attention to eye care. It’s said that if you take care of your eyes, you can surely be healthy.     1     Natural eye care should be put in a number one place. There are several causes leading to poor eyesight like not enough food, genes (基因) and aging (老化).     2     If you happen to work in front of the computer, it is best to take a break every once in a while.

Something dirty can cause redness and make you feel uncomfortable. It is bad for your eyes, too. If this happens, the best way is to clean your eyes by using cold water.     3     For example, sunglasses are not just for fashion but they can also serve as a great way to protect your eyesight from UV rays.

    4     Remember that vitamins A, C and E are good for eyes. Try to eat food groups that have these vitamins. And you should do eye exercises because exercise protects your eyesight, too. If a person exercises regularly and eats the right kind of food, his eyes will stay in good condition for a long time.

    5     In a word, eye care is very important, however old a person is.

5 . Eyesight plays a very important role in our daily life. Every waking moment, the eyes are working to see the world around us. Over forty percent of Americans worry about losing eyesight, but it's easy to include steps into our daily life to ensure healthy eyes. Here are five suggestions for a lifetime of healthy eyesight:

Schedule yearly exams.

    1     Experts advise parents to bring babies 6 to 12 months of age to the doctor for a careful check. The good news is that millions of children now can have yearly eye exams and following treatment, including eyeglasses.

Protect against UV rays .

Long-term stay in the sun creates risk to your eyes. No matter what the season is, it’s extremely important to wear sunglasses.     2     Give your eyes a break.

Two-thirds of Americans spend up to seven hours a day using computers or other digital products.     3     Experts recommend that people practice the 20/20/20 rule: every 20 minutes, take a 20-second break and look at something 20 feet away.

    4    .

As part of a healthy diet, eat more fruits and vegetables each day. Vitamins C and E help protect eyesight and promote eye health.

Practice safe wear and care of contact lenses.

Many Americans use contact lenses to improve their eyesight. While some follow the medical guidance for wearing contact lenses, many are breaking the rules and putting their eyesight at risk.     5    

Otherwise: you may have problems such as red eyes, pain in the eyes, or a more serious condition.

6 . Researchers continue to show the power behind our sense of smell. Recent studies have found, among other things, that the smell of foods like pizza can cause uncontrollable anger in drivers on roads.

The review explains that smell is unique in its effects on the brain. According to Conrad King, the researcher who carried out the review, "more than any other senses, the sense of smell goes through the logical part of the brain and acts on the systems concerned with feelings. This is why the smell of baking bread can destroy the best intentions of a dieter."

Smell, which dictates the unbelievable complexity of food tastes, has always been the least understood of our senses. Our noses are able to detect up to 10,000 distinct smells. Our ability to smell and taste this extremely large range of smells is controlled by something like 1,000 genes (基因), which make up an amazing 3% of the human genome. Researchers Richard Axel and Linda Buck were together awarded a Nobel Prize in 2004 for their ground-breaking research on the nature of this extraordinary sense. These two scientists were the first to describe the family of 1,000 olfactory (嗅觉) genes and to explain how our olfactory system works.

According to one study in the research review, smelling fresh pizza or even the packaging of fast foods can be enough to make drivers feel impatient with other road users. They are then more likely to speed and experience uncontrollable anger on roads. The most reasonable explanation is that these can all make drivers feel hungry, and therefore desperate to satisfy their appetites.

In contrast, the smells of peppermint and cinnamon were shown to improve concentration levels as well as reduce drivers’ impatience. Similarly, the smells of lemon and coffee appeared to promote clear thinking and mental focus.

However, the way genes regulate smell differs from person to person. A study by researchers in Israel has identified at least 50 olfactory genes which are switched on in some people and not in others. They believe this may explain why some of us love some smells and tastes while others hate them. The Israel researchers say their study shows that nearly every human being shows a different pattern of active and inactive smell-detecting receptors.

7 . Have you ever wished you could see in the dark as well as an animal? In action movies, we often see characters wearing special glasses that reveal（显示）things that can't be seen in darkness. Everything looks green, but we can see the shapes and outlines clearly. As a matter of fact, this is somewhat similar to the way animals' night vision (视力) works.

You may have noticed eyeshine in pictures of animals, or seen it for yourself when light hits an animal's eyes. Dogs, cats, and many other animals have tissue (组织) called the tapetum lucidum（光神经纤维层） in each eye. The purpose of this tissue is reflect (反射) light deeper into the eye. For many animals, it leads to their excellent night vision, and it helps them hunt.

Different types of animals have different colors of eyeshine. The light reflecting back from the eyes of dogs and cat is likely to be yellow. Rats and birds usually have eyes that shine red. Other animals’ eyes may reflect white, yellow, green, or pink light. In each case, the color is related to the type of cells that make up the tapetum lucidum, as well as the chemicals inside the cells.

Eyeshine has the function of improving animals' night vision, but humans have found other uses for it. For example, when people are searching for certain types of animals, their eyeshine may be helpful in recognizing or discovering them. Also, eyeshine has inspired humans to invent substance (物质) that reflect light at night. Strips containing this substance are used to warn us of safety risks such as   raised parts of roads. Even though humans cannot see so well at night, we have still found ways to benefit from this amazing animal feature.

Guides on how to prevent hair lossHair loss is a condition that affects a good number of the human population. There are many reasons for that.    1    Drink at least eight glasses of water as the day wears on if you want to improve the texture (质地) of your hair. Water helps to reduce the free radicals (自由基) inside your body, so that you can have a strong head of hair for many years. Make water your primary liquid during the day.    2    Research has shown that men who live in polluted neighborhoods may experience hair loss, because polluted things enter their bloodstream and damage their hair.Find at least one hour during the day to exercise.    3    Aim to exercise at least three days a week to keep a healthy head of hair.Keep a balanced diet, including plenty of fresh fruit and vegetables. Keeping your whole body healthy will also keep your hair healthy, and healthier hair is likely to last longer.    4    Making sure that you’re eating foods rich in iron is a great way you can help strengthen your hair and prevent it from falling out. Think of eating foods like green leafy vegetables, raisins (葡萄干) and other dried fruits, and even whole grain foods.    5    

9 . Feifei, an 11-year-old boy from Xuzhou, Jiangsu Province, suffered from a sudden acute eye disease which has almost led to blindness. The disease was caused by excessive(过度的)eye fatigue(疲劳)during the winter vacation, during which he played computer games for continuous 10 days and nights.

Many youngsters in China nowadays are increasingly addicted to computer games and other electronic products. This is followed by a series of health problems, with the most typical case being myopia, or nearsightedness.

According to the latest research report released by the World Health Organization (WHO), the myopia     rate among Chinese teenagers ranks first in the world—70 percent of high school and college students. The rate is nearly 40 percent in primary school students, while it is only 10 percent for their peers in the United States.

There are at least 10 million people in China with severe myopia, and they are likely to get pathological(病理性的)myopia in middle age. Pathological myopia can't be treated with glasses or surgery, and it is one of the biggest factors that lead to blindness, Xu Xun, director of the ophthalmology(眼科学) department at Shanghai General Hospital, pointed out.

Experts explain that two major factors lead to the high rate of myopia among Chinese people. One is high academic pressure, and the other one is excessive use of electronic devices over a long period of time. Genetics, on the other hand, are not the main reason, as only 20 percent of Chinese people had myopia in the 1960s.

"Teenagers are now faced with severe academic pressure, which means they often study without natural light. This increases their risk of becoming nearsighted," Xu said.

Experts suggest that youngsters maintain a proper balance between study and rest so as to protect their eyesight, and parents should play an active role in the process.

10 . Easy Ways to Keep Your Brain Sharp

Everyone is forgetful, but as we age, we start to feel like our brains are slowing down a bit- -and that can be a very annoying thing.     1    Read on for some techniques worth trying.

1.     2    

People who regularly made plans and looked forward to upcoming events had a 50 percent reduced chance of Alzheimer’s disease (早老性痴呆症)，according to a recent study.     3    Something as simple as setting a goal to have a weekly coffee date with a friend will do. There’s evidence that people who have a purpose in life or who are working on long or short-term goals appear to do better. In other words, keep your brain looking forward.

2. Go for a walk.

Mildly raised glucose (葡萄糖) levels can harm the area of the brain that helps you form memories and physical activity can help get blood glucose down to normal levels. In fact, exercise produces chemicals that are good for your brain.     4    

3. Learn something new.

Take a Spanish class online, join a drawing club, or learn to play cards. A study found that mental stimulation (刺激) limits the weakening effects of aging on memory and the mind. But the best thing for your brain is when you learn something new and are physically active at the same time.     5    Or go dancing with your friends.