有利于人体健康的基于科学的健康饮食与锻炼

Louis J. Ignarro, 路易斯J. 伊格纳罗 博士 

UCLA医学院，分子与医学药理学教授，美国，加利福尼亚州，洛杉机

　　心血管疾病是全球发病率与死亡的首位原因。近二十年来，心血管疾病的发生率有上升趋势，特别是在女性中更为明显。尽管女性的首要死亡原因曾经是癌症，但如今主要原因为心血管疾病。当代，生活方式的改变解释了这一突然逆转，同时解释了近代心血管疾病发生率持续增加的原因。心血管疾病很大程度上是一种生活方式类疾患，因此它可以通过改变生活方式而变化。不健康的饮食，包括有饱和脂肪、红色肉类、包装食物中添加氢化油、食物中添加盐、水果与蔬菜数量的不足、富含抗氧化剂食物数量的不足致使了心血管疾病的发展。而且，久坐方式与肥胖进一步增加了心血管疾病的发生率。正因为这种不良生活方式已经危及到人体健康状况，因此改变生活方式将可以引导人体健康的改善。

　　１９９８年，生理学或医学诺贝尔奖被授予三位科学家，由于他们发现了一种小分子物质，一氧化氮（ＮＯ），是在体内广泛分布的保护机体抵抗心血管疾病与其他疾病的信号分子。进一步研究表明，一氧化氮的缺乏可能导致糖尿病、心血管疾病与其他疾病，而补充一氧化氮可预防与逆转此类疾病状态。不健康饮食与久坐生活方式与一氧化氮缺乏密切相关，而健康饮食与锻炼与一氧化氮产量与作用的明显增加有关。食入含有抗氧化剂不足的脂肪类饮食与盐类饮食将导致一氧化氮产量和作用减少。这类情况见于肥胖与糖尿病，这些疾病具有炎症、氧化应激的特征，两者均造成一氧化氮快速破坏。锻炼显著增加了一氧化氮产量，而久坐生活方式则导致一氧化氮产量低于正常。锻炼对于人体健康是必要的，因为锻炼将导致稳定的且持续的产生充足的一氧化氮，使机体能够保护自身预防心血管疾病与其他疾病。

　　一氧化氮直接由Ｌ－精氨酸产生，一种存在于所有食物蛋白质(肉、鸡、黄豆、鱼、牛奶、坚果、谷物)中的基本氨基酸。富含蛋白质与Ｌ－精氨酸的食物将增加机体内一氧化氮产量。由于一氧化氮可被氧化剂（饱和脂肪、炎症、氧化应激相关的氧自由基）快速破坏，摄入富含抗氧化剂的食物对于预防一氧化氮缺失是重要的。健康食物所致的一氧化氮产量增加可进一步通过经常、充足的锻炼而增强。增加锻炼而使一氧化氮产量增加的原因是动脉内血流量的增加刺激心血管系统内的L-精氨酸转化为一氧化氮。因此，健康饮食配以持续锻炼的规划为何以及如何能够预防和逆转心血管疾病，并且由此降低了这种生活方式所致疾病的死亡率，就应该清楚了。

Science-Based Requirement of Healthy Diet and Exercise for Human Health

Louis J. Ignarro, Ph.D.  Professor of Molecular and Medical Pharmacology, UCLA School of Medicine, Los Angeles, California, USA

　　Cardiovascular disease is the number one cause of morbidity and untimely death throughout most of the world.  The incidence of cardiovascular disease has risen over the past two decades, and this is especially evident in women.  The leading cause of death in women was cancer but today the leading cause is cardiovascular disease.  Lifestyle changes account for this sudden reversal as well as for the continued increase in the incidence of cardiovascular disease in modern times.  Cardiovascular disease is largely a lifestyle disease which, therefore, can be changed by altering lifestyle.  Unhealthy diets consisting of saturated fats, red meats, hydrogenated oils added to packaged foods, salt added to foods, inadequate quantities of fruits and vegetables, and inadequate quantities of antioxidant-rich foods have contributed to the development of cardiovascular disease.  Moreover, more sedentary lifestyles and obesity have further increased the incidence of cardiovascular disease.  Just as this detrimental change in lifestyle has worsened the state of human health, so can a reversal in lifestyle lead to the improvement of human health.

　　In 1998, the Nobel Prize in Physiology or Medicine was awarded to three scientists for their discoveries that the tiny molecule, nitric oxide (NO), is a wide-spread signaling molecule in the body that protects against cardiovascular and other diseases.  Further studies showed that deficient states of NO can lead to diabetes, cardiovascular disease and other diseases, whereas supplementation with NO can prevent and reverse such disease states.  Unhealthy diets and sedentary lifestyles are closely associated with NO deficiency, whereas healthy diets and exercise are linked to markedly increased production and action of NO.  Fatty and salty diets with inadequate antioxidant intake will lead to decreased NO production and action.  Such conditions exist in obesity and diabetes, which are characterized by inflammation and oxidative stress, both of which cause the rapid destruction of NO.  Exercise markedly increases NO production, whereas a sedentary lifestyle results in below normal NO production.  Exercise is healthy for the human body because it brings about a steady and continuous production of sufficient NO to enable the body to protect itself against cardiovascular and other diseases. 

　　NO is produced directly from L-arginine, a basic amino acid that is present in all dietary proteins (meats, chicken, soy, fish, dairy, nuts, grains).  Foods rich in protein and L-arginine will boost NO production in the body.  Since NO is rapidly destroyed by oxidants (oxygen radicals associated with saturated fats, inflammation and oxidative stress), the ingestion of foods rich in antioxidants (fish, fruits, vegetables) is essential to protect against the loss of NO.  The increased NO production resulting from a healthy diet can be further enhanced by frequent and adequate exercise.  The reason why exercise increases NO production is that the increased blood flow throughout the arteries stimulates the conversion of L-arginine to NO throughout the cardiovascular system.  Therefore, it should be clear why and how a healthy diet coupled to a continuous exercise program can both prevent and reverse cardiovascular disease and thereby lower the incidence of death attributed to this lifestyle disease.