Research has revealed that human metabolic processes produce something known as a "free radical." These free radicals cause a kind of oxidation which damages normal cells and weakens the body's immune response. This can lead to illness, aging and even death. Free radicals have also been implicated as a possible cause of cancer.
研究發現，人體在新陳代謝的過程中，會產生一種叫做「自造成破壞正常細胞、減弱抵抗力的氧化作用，最後導致疾病、老化、甚至死亡，這也是導致癌症的主要兇手。