The results presented in this review suggest that the impact of nutrition on obstructive lung disease is most evident for antioxidant vitamins, particularly vitamin C and, to a lesser extent, vitamin E. By decreasing oxidant insults to the lung, antioxidants could modulate the development of chronic lung diseases and lung function decrement. Antioxidant vitamins could also play an important role in gene-environment interactions in complex lung diseases such as childhood asthma. Data also suggest that omega-3 fatty acids may have a potentially protective effect against airway hyperreactivity and lung function decrements; however, relevant data are still sparse. Although epidemiologic data suggest that consumption of fresh fruit may reduce risk of noncarcinogenic airway limitation, there are no clear data on which nutrients might be most relevant. While some studies evaluate daily intake of vitamin C, other studies use fruit consumption as a surrogate for antioxidant intake. Given the dietary intercorrelations among antioxidant vitamins, particularly vitamin C, beta-carotene, and flavonoids, as well as other micronutrients, it may be difficult to isolate a specific effect. Some population subgroups with higher levels of oxidative stress, such as cigarette smokers, may be more likely to benefit from dietary supplementation, since some studies have suggested that antioxidant intake may have a greater impact in this group. Studies of lung function decrement and COPD in adults suggest that daily intake of vitamin C at levels slightly exceeding the current Recommended Dietary Allowance (60 mg/day among nonsmokers and 100 mg/day among smokers) may have a protective effect (20). In the Schwartz and Weiss (85) and Britton et al. (87) studies, an increase of 40 mg/day in vitamin C intake led to an approximate 20-ml increase in FEV1. Daily mean vitamin C intakes in these studies were 66 mg and 99.2 mg, respectively, and the highest intake level (178 mg/day) was approximately three times the Recommended Dietary Allowance. Although the amplitude of the effect was modest, if these effects accumulate over 20-30 years, they could have a meaningful impact on the rate at which pulmonary function declines, particularly in symptomatic subjects (85). Longitudinal data support the hypothesis that fresh fruit consumption has a beneficial impact on the lung (95). Among children, consumption of fresh fruit, particularly fruit high in vitamin C, has been related to a lower prevalence of asthma symptoms and higher lung function (64). This effect was observed event at low levels of fruit consumption (one or two servings per week vs. less than one serving per week), which suggests that a small increase in dietary intake could have a beneficial effect. Consumption of fish has also been related to lower airway hyperreactivity among children (75) and higher lung function in adults (100); however, longitudinal data do not provide evidence that increased omega-3 fatty acid intake protects against lung disease (101). Experimental studies of persons with asthma suggest that magnesium infusion may have a place in the acute treatment of asthma, but it does not seem to have long-term benefits. The studies of sodium, selenium, and fish oils do not show convincing evidence of clinical benefits. Studies of vitamin C supplementation suggest a short-term protective effect on airway responsiveness and pulmonary function. It remains to be proven whether consistent use of vitamin C would have a protective effect on the evolution of chronic asthma. Results from supplementation studies conducted among subjects exposed to high levels of oxidants (57-60) suggest that daily intake of antioxidant vitamins exceeding the Recommended Dietary Allowance may have a beneficial effect on lung airways and that intake higher than the Recommended Dietary Allowance should be recommended for populations chronically exposed to photooxidant air pollutants (such as ozone), cigarette smoking, or vigorous exercise. It is difficult to determine the amounts of antioxidant vitamins that people should consume. In particular, although vitamin C was shown to have maximum bioavailability when given in a single dose of 200 mg (102), experiments on which this finding was based were conducted under normal conditions. Guidelines from the US National Cancer Institute (103) recommend consumption of five servings of fruit and vegetables daily, corresponding to a vitamin C intake exceeding 200 mg. Dietary surveys carried out in the US population indicate that less than 12 percent of US children and adults meet this recommended level of intake (104). Diet appears to be an important cofactor in the development of obstructive lung disease, although data are still sparse. There is a need for further research in experimental and epidemiologic settings to better understand the physiologic effects of antioxidant vitamins, omega-3 fatty acids, and other nutrients on lung tissues. The impact of diet on the incidence and evolution of asthma and COPD should be investigated using a cohort design that accounts for known risk factors. This will allow researchers to evaluate the exposure-disease relation over an adequate time frame and obtain insight into the causality of the relation. Some of these studies should enroll infants and young children to determine the impact of early diet on respiratory health. Research should also focus on the equally challenging policy issues--namely, finding effective methods of convincing people to increase their daily consumption of fresh fruits and vegetables, to stop smoking cigarettes, and to minimize their environmental and occupational exposure to pollutants and other agents that cause respiratory disease.

中文翻译：

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饮食和阻塞性肺疾病。

这篇综述的结果表明，营养对阻塞性肺疾病的影响最明显的是抗氧化剂维生素，特别是维生素C，在较小程度上还包括维生素E。通过减少对肺的氧化剂损害，抗氧化剂可以调节肺脏的发育。慢性肺部疾病和肺功能下降。抗氧化剂维生素在复杂的肺部疾病（如儿童哮喘）中的基因-环境相互作用中也可能起重要作用。数据还表明，omega-3脂肪酸可能对气道反应过度和肺功能下降具有潜在的保护作用。但是，相关数据仍然很少。尽管流行病学数据表明食用新鲜水果可能会降低非致癌性气道受限的风险，但尚无明确的数据表明哪些营养物质最相关。尽管一些研究评估了维生素C的每日摄入量，但其他研究却使用水果消耗量作为抗氧化剂摄入量的替代品。鉴于抗氧化剂维生素（尤其是维生素C，β-胡萝卜素和类黄酮）以及其他微量营养素之间的饮食相互关系，可能难以分离出特定的作用。某些具有较高氧化应激水平的人群，例如吸烟者，可能更可能从膳食补充中受益，因为一些研究表明，抗氧化剂的摄入可能对该组产生更大的影响。对成年人肺功能下降和COPD的研究表明，每天摄入的维生素C略高于当前的推荐饮食标准（不吸烟者为60毫克/天，吸烟者为100毫克/天）可能具有保护作用（20）。在Schwartz和Weiss（85）和Britton等人中。（87）研究表明，维生素C摄入量每天增加40 mg，导致FEV1大约增加20 ml。在这些研究中，每日平均维生素C摄入量分别为66 mg和99.2 mg，最高摄入水平（178 mg /天）约为建议饮食津贴的三倍。尽管影响的幅度不大，但如果这些影响在20到30年内累积，则可能会对肺功能下降的速率产生有意义的影响，特别是在有症状的受试者中（85）。纵向数据支持以下假设：食用新鲜水果对肺有有益影响（95）。在儿童中，食用新鲜水果，尤其是富含维生素C的水果，与哮喘症状的患病率较低和肺功能较高相关（64）。观察到这种效果是在水果消耗量较低的情况下发生的（每周一或两份，而每周少于一份），这表明饮食摄入量的少量增加可能具有有益的作用。食用鱼还与儿童气道高反应性降低（75）和成年人肺功能升高（100）有关。然而，纵向数据没有提供证据表明增加的omega-3脂肪酸摄入可以预防肺部疾病（101）。对哮喘患者的实验研究表明，镁注射液可能在哮喘的急性治疗中占有一席之地，但似乎没有长期的益处。钠，硒和鱼油的研究并未显示出令人信服的临床证据。补充维生素C的研究表明，对气道反应性和肺功能有短期保护作用。持续使用维生素C是否对慢性哮喘的发展具有保护作用还有待证明。在暴露于高水平氧化剂的受试者中进行的补充研究结果（57-60）表明，每天摄入超过建议饮食限额的抗氧化剂维生素可能会对肺气道产生有益影响，应建议摄入高于建议饮食限额的摄入量适用于长期暴露于光氧化性空气污染物（例如臭氧），吸烟或剧烈运动的人群。很难确定人们应该摄入的抗氧化剂维生素的量。特别是，尽管单剂量200 mg维生素C被证明具有最大的生物利用度（102），但这一发现所依据的实验是在正常条件下进行的。美国国家癌症研究所（103）的指南建议每天食用五份水果和蔬菜，相当于维生素C摄入量超过200毫克。在美国人口中进行的饮食调查表明，只有不到12％的美国儿童和成人达到了建议的摄入量（104）。饮食似乎是阻塞性肺疾病发展的重要辅助因素，尽管数据仍然很少。需要在实验和流行病学环境中进行进一步研究，以更好地了解抗氧化剂维生素，omega-3脂肪酸和其他养分对肺组织的生理作用。饮食对哮喘和COPD的发生和发展的影响应采用队列设计进行研究，该队列设计应考虑已知的危险因素。这将使研究人员能够在适当的时间范围内评估暴露与疾病的关系，并深入了解这种关系的因果关系。其中一些研究应招募婴幼儿以确定早期饮食对呼吸系统健康的影响。研究还应着眼于同样具有挑战性的政策问题，即寻找有效的方法，说服人们增加日常新鲜水果和蔬菜的消费，停止吸烟，并最大程度地减少他们在环境和职业上对污染物和其他污染物的接触。引起呼吸系统疾病。