Researchers from Australia and China’s universities compared the effects of five days consumption of conventional milk (containing A1 and A2 β-casein) and A2 milk (contain A2 β-casein only).
“Conventional milk increased serum inflammatory and immune biomarkers, as well as an increased cognitive test error rate compared with A2 milk in the pre-schoolers.”
The findings were published in the Journal of Pediatric Gastroenterology and Nutrition.
The study recruited 75 children aged five and six with mild-to-moderate lactose intolerance.
In a double-blind, randomised, controlled, crossover study, subjects enrolled in a 5-day phase 1 intervention of either conventional milk or A2 milk and blood samples were taken.
They consumed the 250mL milk twice daily after a meal. The milk was provided by a2 Infant Nutrition Limited in Shanghai, China.
Subjects then entered a nine-day washout period before switching over to the other milk product for another five days.
The primary outcome of the study found consumption of conventional milk induced a significant increase (p<0.0001) in gastrointestinal symptoms compared to A2 milk, while A2 milk reduced biomarkers of inflammation.
Researchers said, “These results are also similar to those from a study by Ul Haq and colleagues, who reported that consumption of A1 β-casein induced an inflammatory response by activating the Th2 pathway in a mouse model.”
The researchers also found that after five days of A2 milk consumption, there were significantly higher mean faecal concentrations of acetic acid, butanoic acid, and total short-chain fatty acids SCFA, when compared with consuming conventional milk.
“This is relevant because SCFAs are fermentation products of gut microbiota, with reported anti-inflammatory properties, able to amplify colonic cell function,” researchers added.
“These results are consistent with previous observations in adults that conventional milk reduces SCFA levels and impairs colonic health.”
In this study, consumption of conventional milk was associated with a significantly higher stool frequency and significantly higher Bristol Stool Scale scores compared with the consumption of A2 milk.
They cited the similarity in adults, “The study by Jianqin and colleagues revealed longer gastrointestinal transit times, softer stools, and a greater incidence of diarrhoea, when adults consumed conventional milk.”
“These data suggest that exclusion of A1 β-casein may help alleviate adverse gastrointestinal symptoms.”
The researchers also found that the pre-schoolers performed better in a Subtle Cognitive Impairment Test after consumption of A2 milk.
They noted improved accuracy and results in both automatic and attentional processes.
These data suggest that consumption of A2 milk has a positive effect not only on the gastrointestinal system, but also on cognition in pre-schoolers.
The researchers concluded: “We report that conventional milk induces an inflammatory state that exacerbates the symptoms of digestive discomfort associated with lactose intolerance.
“Consumption of A1 β-casein induces inflammation in the small intestine. A2 β-casein, however, has a much slower rate of proteolytic digestion; therefore, its consumption results in a much lower yield of BCM-7.
“This exacerbation can be reduced by removal of A1 β-casein (via replacement with A2 β-casein), with subsequent improvement in gastrointestinal symptoms and aspects of cognitive function.”
Source: Journal of Pediatric Gastroenterology and Nutrition
DOI : 10.1097/MPG.0000000000002437
Effects of conventional milk vs milk containing only A2 β-casein on digestion in Chinese children: a randomized study
Authors: Xiaoyang Sheng, et al.