Exercise is important in all phases of life, but for seniors, it’s crucial to maintaining independence. Exercise ensures that seniors can get around and continue to do the things they enjoy and helps to prevent serious health conditions. 【小题1】

Strength exercises are among the best exercises for seniors. 【小题2】 These exercises can also improve a senior citizen’s metabolism(新陈代谢), which can be important for the maintenance of healthy blood sugar levels and normal weight.

Balance exercises are good for senior citizens as well because they build up muscles in the legs and strength in the lower body. They can help a senior citizen have better stability, translating into lowered risk of serious falls. 【小题3】

【小题4】 They help improve flexibility, making it easier for an older person to remain physically active and move around without stiffness(僵硬) and pain. Additionally, stretching exercises help senior citizens avoid muscle­related injuries, which can occur in the course of exercising as well as during daily living.

Though exercise is good for senior citizens, it is smart for seniors to speak with their doctors before starting any new exercise program. 【小题5】 In some cases, they may also recommend avoiding certain exercises altogether.

Someday it may be possible for people to deal with their food allergies(过敏)simply by brushing teeth. A New York City-based company has started a trial to test this concept in a small group of peanut-allergy sufferers. The idea is to expose users to small doses(剂量)of an allergen daily, in order to build tolerance to it

“Tying this treatment to a daily routine should help allergy sufferers keep up with regular treatment,” say researchers at Intrommune Therapeutics, which developed the toothpaste. The product may also do a better job than existing therapies(疗法). Several years ago, William Reisacher, an allergist at Weill Cornell Medicine in New York City, was standing in front of a mirror brushing his teeth. “I saw all the foam(泡沫)in my mouth going into all the areas I wanted it to go,” he says. “If food proteins could be delivered as a toothpaste, that would get the treatment to the right cells and make it a routine daily habit.”

“William told me this crazy idea he had, and I thought it was perfect,” says Michael Nelson, cofounder of Intrommune. “The newly started trial of the toothpaste will include 32 peanut-allergic adults to test how well they tolerate increasing doses. Future trials may test toothpastes that contain several different allergens.”

Other allergists support the toothpaste concept, though some worry about dose control and safety. “When there are sores in a patient's mouth or after a patient loses a tooth—allergens may have direct access to the bloodstream, which increases the risk of systemic allergic reactions,” says allergist Sakina Bajowala.“Safety is something I'm going to be watching closely,” she says. “But if they find something that can                    be commercialized and made accessible, and if they can prove it's safe and effective, then fantastic.”

Vitamin D is a key nutrient for health, helping to keep your bones strong while also assisting with muscle and immune function. But people across the globe aren’t getting enough of it, making vitamin D the most popular supplement on the market.

Vitamin D helps your body absorb calcium (钙) from food, which keeps your bones strong and helps prevent osteoporosis, a disease that causes bones to become thinner and less dense. Vitamin D also protects you from more severe conditions such as osteomalacia, or “bone softening,” and it protects kids from rickets (佝偻病). Vitamin D also plays important roles in muscle movement, communication between nerves, and immune defenses against bacteria and viruses, according to the National Institutes of Health’s Office of Dietary Supplements.

All our bodies really need to make vitamin D is sunlight, but the older you become, the harder it is for your thinning skin to produce it when exposed to sunlight, with production decreasing by about 13 percent each decade. People with darker skin have more of the melanin pigment (黑色素) that absorbs the UV rays essential to vitamin D production, so naturally they make less of it. Some estimates show that darker skin is about 90 percent less efficient at making vitamin D compared to lighter skin.

Advice on how to get vitamin D is conflicting. Sunlight is the best source, but we’re told to cover up to avoid skin cancer. Then we’re advised to eat a diet rich in vitamin D even though most foods don’t contain enough of it.

“There are so many recommendations out there, so how do we prioritize what we should be doing and which are the most important things to do?” says Anne Cappola, an endocrinologist and professor of medicine at Penn Medicine.” In some ways it would be easy if all we had to do was take supplements, but it’s more complicated than that.”

It doesn’t hurt to be more mindful about vitamin D. “You definitely want to have enough,” Cappola says, “but more is not always better.”