2006年11月26日美國國家科學院院刊（PNAS）發表了美國奧克蘭特兒童醫院營養與代謝中心埃米斯的綜述“微量營養素攝入低可能加速老年人退行性疾病發生” ，作者提出了一項營養學新理論“微量營養素缺乏,損傷三步曲”。
營養不良常常與許多疾病如癌症、心髒病等的發生相聯係。人類飲食需要宏量營養素（熱量的重要來源）和微量營養素（約40種必需的礦物質、維生素和其他生化物質）。現在的膳食維生素礦物質攝入不足很普遍，大多是由於過多地消耗高能、低微量營養素、加工精細的食物造成的。美國人膳食中維生素礦物質攝入不充分，這可能導致人體慢性代謝紊亂，包括線粒體破壞、脫氧核糖核酸（DNA）損害、染色體破裂，進一步引起氧化損傷和細胞老化，最終引起遲發性疾病（如癌症）發生，這就是“微量營養素缺乏，損傷三步曲”。觸發這“三步曲”的微量營養素缺乏可能加速癌症、老化和神經中樞衰退。因此，作者表示服用多種維生素礦物質補充劑是一種確保終身能達到微量營養素膳食推薦攝入量的保健方法。
對老年人而言，他們需要的營養素並不比年輕人少，但老年人的消化機能逐漸退化、各種消化液的分泌減少、消化酶的活性下降、胃腸道吸收功能下降，再加上許多老年人伴有胃腸動力障礙，導致胃口變差，進食量減少。因此，一方麵是營養素的攝入減少，另一方麵是營養素的吸收減弱，如果不注意營養素的補充則會出現營養素“入不敷出”，最終導致多種營養素缺乏和慢性疾病的發生。如果老年人正在服用一些藥物如阿司匹林、消膽胺等幹擾營養素的吸收和利用，這就是雪上加霜了。
據全國最新營養調查結果顯示，我國60歲以上老年人的營養素補充劑使用率僅為8.5%，遠遠低於歐美發達國家。因此營養學家呼籲：在提倡均衡營養、合理膳食的前提下，通過合理服用維生素礦物質可以改善營養缺乏狀況、預防慢性病的發生和促進健康。
老年人在選購維生素礦物質補充劑時，要特別關注配方是否專為老年人定製，是否強化一些對老年人特別重要的營養素，例如維生素A、E、B6、B12、鈣、鉻、鉀等。大量研究顯示，服用多種維生素礦物質補充劑，能有效降低老年患者血壓，降低冠心病發生的風險，預防缺血性腦卒中的發生，同時還能增加免疫力，防止感染性疾病的發生。
廣州日報
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| | | | | 回答: 缺什麽就會老得快?(ZT) 由 鮮葡萄 於 2007-06-02 13:03:25 Bruce N Ames. Low micronutrient intake may accelerate the degenerative diseases of aging through allocation of scarce micronutrients by triage. PNAS 2006(103): 17589-17594.
Abstract：Inadequate dietary intakes of vitamins and minerals are widespread, most likely due to excessive consumption of energy-rich, micronutrient-poor, refined food. Inadequate intakes may result in chronic metabolic disruption, including mitochondrial decay. Deficiencies in many micronutrients cause DNA damage, such as chromosome breaks, in cultured human cells or in vivo. Some of these deficiencies also cause mitochondrial decay with oxidant leakage and cellular aging and are associated with late onset diseases such as cancer. I propose DNA damage and late onset disease are consequences of a triage allocation response to micronutrient scarcity. Episodic shortages of micronutrients were common during evolution. Natural selection favors short-term survival at the expense of long-term health. I hypothesize that short-term survival was achieved by allocating scarce micronutrients by triage, in part through an adjustment of the binding affinity of proteins for required micronutrients. If this hypothesis is correct, micronutrient deficiencies that trigger the triage response would accelerate cancer, aging, and neural decay but would leave critical metabolic functions, such as ATP production, intact. Evidence that micronutrient malnutrition increases late onset diseases, such as cancer, is discussed. A multivitamin-mineral supplement is one low-cost way to ensure intake of the Recommended Dietary Allowance of micronutrients throughout life. |
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