申論題

2. Mixed Questions Design 

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    People seeking straightforward nutrition advice might have a bone to pick with calcium, a building block of health that can start to seem like a piece from a complicated puzzle. Luckily, the basics – such as understanding why you need it and how to make sure you are getting enough – don't have to be puzzling at all.

    “Calcium is important for overall health,” said Dr. Kristina Petersen, an associate professor of nutritional sciences at Penn State University in University Park, Pennsylvania. “And we know inadequate intake or deficiency causes health problems.” Calcium is best known as the building material for your skeleton. More than 99% of it is in bones and teeth. But calcium also plays several roles related to heart health. It may help regulate blood clotting, heart rhythms and how blood vessels dilate and contract. People whose diets are deficient in calcium have a higher risk of high blood pressure, said Dr. Martha Gulati, director of preventive cardiology in the Smidt Heart Institute at Cedars-Sinai in Los Angeles. But exactly how that works is not fully understood, said Gulati.

    The recommended daily allowance for calcium is 1,000 to 1,200 milligrams a day for adults, depending on age; teens and pre-teens need slightly more. But this is where conversations about calcium can start to sound like a puzzle, or the seating arrangements at a high school cafeteria – because it is all about who calcium is fitting in with at mealtime.

   Without adequate vitamin D, for example, your body cannot absorb much calcium from food. That is particularly important for bone health, Petersen said. Meanwhile, some foods contain compounds that bind with calcium and prevent the body from using it. For example, spinach has a fair amount of calcium, but only about 5% ends up being bioavailable—that is, absorbed into the body. By comparison, about 32% of the calcium in milk is bioavailable.

   “Ultimately, I think that the best way to get nutrients is through our food,” Gulati said. “I don't advocate for a lot of supplements unless somebody truly can't get it from food.”

   Happily, experts have an easy answer to the question of how to get the calcium you need without keeping a nutrition textbook handy: Just eat a range of healthy foods throughout the day. “That should be sufficient,” Gulati said. “Sure, you could schedule your meals to avoid calcium-binding foods at the same time you are eating those that are calcium-rich,” she said. “But I think that's a very difficult way to eat.”

   “By eating a variety of healthy foods throughout your day, chances are you are not always eating something that's calcium-binding,” she said, “and you are probably getting something else that is beneficial.” And the thing about calcium is that there are actually lots of sources out there,” she said.

   Plant-based milks can be a good dairy alternative for people who are lactose intolerant or who don’t consume animal-based products. “However, you do need to make sure that you are choosing a calciumfortified one,” Petersen said.

   Gulati happens to be vegan and draws on a long list of non-dairy options to meet her needs. “Tofu is one great source of calcium,” she said. “Nuts, particularly almonds, are another good source, as are leafy greens, especially when cooked.”

   Other sources include beans, winter squash, sardines and canned salmon.

   Petersen said she finds dairy to be a convenient way to get her calcium. She likes milk in her coffee and is a big fan of yogurt and its many portable forms. “You can just put one in your bag and take it to work,and that's your snack.”

(1) Summarize the following article. Your total word count should   range from 200 to 250 words.