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. 2015 Aug 13;7(8):6751-79.
doi: 10.3390/nu7085309.

Adaptation to Lactose in Lactase Non Persistent People: Effects on Intolerance and the Relationship Between Dairy Food Consumption and Evalution of Diseases

Free PMC article

Adaptation to Lactose in Lactase Non Persistent People: Effects on Intolerance and the Relationship Between Dairy Food Consumption and Evalution of Diseases

Andrew Szilagyi. Nutrients. .
Free PMC article


Dairy foods contain complex nutrients which interact with the host. Yet, evolution of lactase persistence has divided the human species into those that can or cannot digest lactose in adulthood. Such a ubiquitous trait has differential effects on humanity. The literature is reviewed to explore how the divide affects lactose handling by lactase non persistent persons. There are two basic differences in digesters. Firstly, maldigesters consume less dairy foods, and secondly, excess lactose is digested by colonic microflora. Lactose intolerance in maldigesters may occur with random lactose ingestion. However, lactose intolerance without maldigestion tends to detract from gaining a clear understanding of the mechanisms of symptoms formation and leads to confusion with regards to dairy food consumption. The main consequence of intolerance is withholding dairy foods. However, regular dairy food consumption by lactase non persistent people could lead to colonic adaptation by the microbiome. This process may mimic a prebiotic effect and allows lactase non persistent people to consume more dairy foods enhancing a favorable microbiome. This process then could lead to alterations in outcome of diseases in response to dairy foods in lactose maldigesters. The evidence that lactose is a selective human prebiotic is reviewed and current links between dairy foods and some diseases are discussed within this context. Colonic adaptation has not been adequately studied, especially with modern microbiological techniques.

Keywords: digesters; lactase; lactose; maldigesters adaptation.


Figure 1
Figure 1
Bar graph represents the summary Odds Ratios or Relative Risks of the effect of dairy foods on colorectal cancer based on a meta-analysis of 67 studies [118]. In individual studies, the highest dairy food intakes was compared with the lowest intake. The three bars with 95% confidence intervals represent the outcome of regional meta-analyses of individual regional studies. The regions are divided according to percent lactase distribution (Lactase Persistent (LP)/Lactase Non persistent (LNP)) of the populations into low LNP (≤20%) (North America, Western Europe, Australia, N represents the number of studies 42) mid LNP (21%–79%; mean 50%) (South Europe, Latin America, N of studies 17) and high LNP (≥80%) (Asia, N of studies 8).Meta analyses include both case-control and cohort studies, although the original analyses also reported these types of studies separately. Modest but statistically significant reduction of colorectal cancer is noted in high (RR = 0.84, 95%CI = 0.73–0.97) and low LNP (RR = 0.80, 95% CI = 0.73–0.88) regions. In the mid LNP studies, a small non-statistically significant reduction in CRC is noted (RR = 0.92, 95% CI = 0.79–1.06). Modified figure reproduced from Szilagyi et al. [118] with permission from Francis & Taylor.

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