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  • 期刊

From 'Lactose Intolerance' to 'Lactose Nutrition'

從“乳糖不耐”到“乳糖營養”

摘要


乳糖不耐症的概念建構在西方及開發中經濟體的醫學。其證據為佔全球少數的北歐衍生族群,其腸道乳糖酶活性續存至兒童晚期及整個生命週期。這些人擁有rs49882359等位基因(C/T)的T單核甘酸多型性(SNP),又被稱為C/T-13910,其MCM6基因正向影響乳糖酶LCT基因。其他在非洲及中東的乳糖酶續存族群,他們有不同的基因變異。這些SNPs代表自農業革命及營養依賴的生態適應與乳品業的共同演化。意即,多數人因為小腸乳糖吸收不良產生的腸胃道症狀與其是否為乳糖酶非續存(LNP)關係不大。LNP者,大腸菌相的乳糖酶能夠發酵乳醣,所以糞便中並無乳糖存在。短鏈脂肪酸(SCFAs)及氣體(氫氣、二氧化碳及甲烷)是否引起症狀,端看其劑量。一個LNP者,在任何時間均可消化最多25 公克的乳糖。食物或餐點內容、腸道菌相的特性、年齡及其他因素,才是影響其耐受性原因。因此,LNP者的乳糖不耐是一種失調或是疾病的主張是一種錯置及文化觀點。真正重要的是常被攝取的乳製品是否會引起症狀。也就是說,建議以乳製品耐受性測試取代乳糖不耐症測試。

並列摘要


The concept of lactose intolerance has become embedded in Western medicine and developing economy medicine. It is based on evidence that intestinal lactase activity persists into later childhood and throughout life in only a minority of the world's population, notably northern European-derived populations. These people have the T single nucleotide polymorphism (SNP) of the rs49882359 allele (C/T), also known as C/T-13910, the MCM6 gene which positively influences the lactase LCT gene. Other lactase persistent (LP) populations are found in Africa and the Middle East with different genetic variants. These SNPs represent co-evolution with dairying since the agricultural revolution and nutrient-dependent ecological adaptation. That said, gastrointestinal symptoms considered due to small intestinal lactose malabsorption are poorly correlated with lactase non-persistence (LNP), the situation for most people. With LNP, colonic microbiome lactase enables lactose fermentation to occur so that none is found in faeces. Whether the short chain fatty acids (SCFAs) and gases (hydrogen, carbon dioxide and methane) produced cause symptoms is dose-dependent. Up to 25 g of lactose at any one time can usually be consumed by a LNP person, but its food and meal pattern context, the microbiomic characteristics, age and other factors may alter tolerance. Thus, the notion that lactose intolerance is a disorder or disease of LNP people is misplaced and has been one of cultural perspective. What actually matters is whether a particular dairy product as normally consumed give rise to symptoms. It is, therefore, proposed that lactose tolerance tests be replaced with dairy food tolerance tests.

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