The Search For The Anti Ageing Pill Reading Answers: IELTS Reading Practice Test

The Search For The Anti Ageing Pill Reading Passage

Scientists are searching for a drug that can extend life and restore youthful vitality in government laboratories and other locations. Caloric restriction research is illuminating the path.

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No drug currently available has been demonstrated to slow human ageing, the accumulation of molecular and cellular damage that increases vulnerability to infirmity as we age, as recently noted by ageing researchers. One intervention, however, which increases longevity and maintains good health in a variety of animals is the consumption of a low-calorie* but nutritionally balanced diet. These results imply that caloric restriction may also increase longevity and postpone ageing in humans.

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Unfortunately, people would likely need to consume fewer calories—roughly 30% fewer, or 1,750 calories per day instead of 2,500—to get the most benefit. Few mortals could maintain such a strict regimen, especially for so long. What if, however, a drug could be developed that, without actually making people reduce their intake of food, mimicked the physiological effects of doing so? Could this "caloric restriction mimetic," as we like to call it, help people live longer and healthier lives by delaying the onset of age-related diseases like diabetes, arteriosclerosis, heart disease, and cancer until later in life? After discovering a chemical agent that appeared to replicate many of the advantages of caloric restriction in rodents, scientists first raised this question in the middle of the 1990s. Although a substance that could safely accomplish the same feat in people has not yet been discovered, the search has been fruitful and given rise to optimism that CR mimics may one day be created.

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The benefits of caloric restriction

To comprehend the body's many effects of caloric restriction, researchers began looking for CR mimics. When they discovered that rats fed a low-calorie diet lived on average longer than free-feeding rats and also had a lower incidence of conditions that become more prevalent as people age, scientists first realised the benefits of the practice more than 60 years ago. Additionally, some of the treated animals lived longer than the oldest-living animals in the control group, indicating that not only did the average lifespan increase but also the maximum lifespan (the oldest attainable age). Various interventions, such as infection-fighting medications, can lengthen the average lifespan of a population, but only measures that slow ageing will lengthen life span to their maximum lifespan. 

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The rat results have been repeatedly replicated and applied to a wide variety of animals, including yeast, fruit flies, worms, fish, spiders, mice, and hamsters. Studies were previously restricted to short-lived animals that were genetically distinct from humans. However, caloric restriction studies being conducted on the rhesus and squirrel monkeys, two species more closely related to humans, have given scientists hope that CR mimetics may one day benefit humans.

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The monkey studies show that calorie-restricted monkeys have lower body temperatures and insulin levels than control animals that eat normally, and they maintain more youthful levels of some hormones that tend to decline with age.

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Indicators of risk for age-related diseases also favour caloric-restricted animals. For instance, they have more normal blood glucose levels and lower blood pressure and triglyceride levels, both of which indicate a lower risk for diabetes, which is characterised by abnormally high blood glucose levels. More recently, it has been demonstrated that rhesus monkeys kept on calorie-restricted diets for a prolonged period of time—nearly 15 years—have fewer chronic diseases. However, further observation of them and the other monkeys is required to determine whether low-calorie diets can lengthen monkeys' average and maximum life spans. CR mimetics would change the fundamental processes that cause ageing, in contrast to the numerous elixirs being advertised as the newest anti-ageing treatment. Our goal is to create substances that trick cells into turning on maintenance and repair.

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How a prototype caloric-restriction mimetic works

The most thoroughly researched candidate for a caloric-restriction mimic, 2DG (2-deoxy-D-glucose), functions by impairing how cells use glucose. It cannot be used on humans because it has been shown to be toxic in animals at some doses. However, it has been shown that certain chemicals can mimic the results of caloric restriction; the challenge is in selecting the right one.

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The molecule that fuels numerous bodily processes, ATP (adenosine triphosphate), is produced by cells using the glucose from food. Caloric restriction lowers ATP production and reduces the amount of glucose that enters cells by limiting food intake. When 2DG is given to animals who eat normally, a lot of glucose enters the cells, but the drug prevents the majority of it from being processed, which lowers ATP synthesis. Researchers have put forth a number of theories as to why preventing the production of ATP and processing of glucose might delay ageing. One possibility relates to the release of free radicals by the ATP-making machinery, which is thought to speed up ageing and age-related diseases like cancer by harming cells. Reduced use of the equipment should keep their output in check and limit the damage. According to another theory, cells may switch into an anti-ageing mode that prioritises the preservation of the organism over such 'luxuries' as growth and reproduction if their ability to process glucose is reduced. This would happen even if the food wasn't actually scarce.

caloric: a measure of the energy value of food

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