Dados do Trabalho

Título

DOES MILK PREVENT OR PROMOTE INFLAMMATION? INSIGHTS FROM IN VITRO ASSAYS

Introdução

Milk is widely consumed due to its high nutritional value, having possible protection against infections and anti-inflammatory activity. Conversely, milk’s microbiota reduces its shelf life and can pose health risks. Milk processing can introduce changes to its components, having led to speculation about a potential to induce chronic inflammation, which is associated with the development of a variety of metabolic, autoimmune, and degenerative diseases, being essential to understand the role of food in its etiology. The present study aimed to investigate processed milk samples for their potential to modulate inflammatory responses in an intestinal in vitro model, contributing to the current debate about the effects of processed milk’s consumption.

Material e Métodos

Raw, pasteurized, and ultra-high temperature (UHT) homogenized milk were subjected to an in vitro simulated digestion process and human colorectal adenocarcinoma cells (Caco-2) and Abelson murine leukemia macrophages (Raw 264.7) were cultivated in vitro and challenged with undigested and digested milk samples.

Resultados e Discussão

Results indicated that post-digestion, pasteurized milk decreased the production of IL-8 in 59% as opposed to UHT milk, which increased cytokine production in 115%, indicating that the less processed sample exerted an anti-inflammatory activity. In macrophages, UHT homogenized milk increased the production of inflammatory cytokines up to 238%, showing that more processing could lead to a pro-inflammatory response. Raw milk presented a 321% increase in IL-6 production, indicating a pro-inflammatory effect, as observed in processed milk samples.

Conclusão

The observed effects could be linked to the triggering of an inflammatory cascade after the release of NF-κB from the nucleus, culminating in the increase of inflammatory markers. Formation of Maillard reaction products and an increased presence of free fatty acids in processed milk are some of the possible explanations to this effect, in addition to the loss of anti-inflammatory compounds present in less processed milk samples. Moreover, these new findings suggest that consumption of raw milk, although lacking processing, can be potentially inflammatory giving its vast microbiota, in addition to the well-known risks of its consumption. It also suggests that the processing of milk can prevent or promote inflammation depending on to the type of processing to which it was submitted.