Many people, when they are feeling miserable from a cold or the flu, get the urge to gorge on food. But picking the right foods can benefit and even speed healing.

"This is more or less a new area," said Kerry Neville, a Seattle dietitian and spokeswoman for the American Dietetic Association. "There has been some good research, and we'll be seeing more. But it remains to be seen how much of this can actually be helpful."

Teasing out how and where food can benefit is difficult because our immune systems -- a coordinated system of signals sent and received, feedback loops and multiple redundancies to ensure that foreign molecules are identified and destroyed if they are harmful -- are so complex. A breakdown in any part of the system leaves the whole body susceptible to infection and illness.

And lifestyle and environment can cause small breakdowns in the system all the time. Smoke, air quality, sunlight and poor diet can all contribute to a weakened immune system, particularly in the form of free radicals. These highly reactive molecules with unpaired electrons can break down cells, leaving them vulnerable to invading viruses and bacteria.

Antioxidants, a type of chemical found in plants, help neutralize free radicals and protect cells, thus bolstering the immune system. Antioxidants often give plants their color and can also include vitamins C, A, and E. Experts estimate that there are many more antioxidants that are as yet unidentified.

And studies have shown that some of the protective vitamins and minerals, when given alone, do not benefit people as much as getting those nutrients from their diets.

很多人在遭受伤风或流感的痛苦侵扰时,往往会采取大量进食的方式摆脱病害的困扰,选择适当的食物不仅对健康有益,更能有效地促进身体的复原.

西雅图营养学家兼美国饮食协会女代言人Kerry Neville发言说:"这是个崭新的领域,对此已经进行了一些很好的研究,我们还将看到更多的新研究产生,但是对于食物能有效促进身体康复的实际程度还有待进一步的深入研究."

要弄清食物是如何对身体哪部分有益并非易事,因为人体免疫系统结构复杂,主要是由信号收发,反馈回路以及复合备份共同配合协作,及时辨析并破坏外界有害分子确保身体机能的正常运行,该系统任何部分的损伤都会导致整体免疫力下降,易受感染,遭受疾病侵害.

生活方式,外界环境都能导致免疫系统的微弱损伤,吸烟,空气质量,阳光以及不良饮食习惯均会以自由基的形式削弱系统免疫力.这些带未配对电子的高活性分子能损伤细胞,使之更易受病毒细菌的侵袭.

植物体内有种化学物质---抗氧化剂,能抑制自由基保护细胞免受损害,从而维持免疫能力.不同的抗氧化剂有各自不同的颜色,可分为维他命C,A和E.专家推测还有更多的未经确认的抗氧化剂存在植物体内.

研究表明,饮食中吸取的一些维他命和矿物质所起的功效远大于单独服用时所起的功效.