Study suggests milk with A2 β-casein causes less gastrointestinal discomfort

The study, which was funded by The a2 Milk Company, monitored the gastrointestinal symptoms of 600 Chinese adults with self-reported lactose intolerance and digestive discomfort after drinking milk.

Methods​

The double blind, randomized, cross-over study, subjects were given milk containing A1 and A2 beta casein (conventional milk) and A2 beta casein milk (provided by The a2 Milk Company) in randomized treatment sequences: receiving conventional milk on the first day and milk containing A2 beta casein on the eighth day, or vice versa, according to the study.

Subjects used a food diary to record milk intake and completed a visual analogue scale (VAS) to monitor their gastrointestinal symptoms after one hour of consuming the milk sample. After three hours, subjects provided a urine sample and another VAS for gastrointestinal symptoms.

The subjects continued a dairy-free diet for seven days and on day eight, returned to the study site to repeat the study procedures and consume the corresponding milk product.

Results​

Gastrointestinal symptoms (bloating, abdominal pain, stool frequency, etc.) scores were graded on a numeric scale at three different times -- one,

three, and 12 hours following consumption of each milk sample.

The combined results of the gastrointestinal reactions of all participants after consuming conventional milk ranged between 0 and 3 (0=no discomfort), and A2 β-casein milk symptoms scores ranged between 0 and 2.  

"The symptom scores for all six symptoms were consistently lower with milk containing A2 β-casein than with conventional milk at both 1 and 3 h after consumption,"​ researchers said. 

“These findings suggest that, in some individuals with self-reported lactose intolerance, the adverse gastrointestinal symptoms following milk intake might be related to the presence of A1 β-casein in milk rather than lactose itself.”​

Source: Nutrition Journal

https://doi.org/10.1186/s12937-017-0275-0​

“Effects of cow’s milk beta-casein variants on symptoms of milk intolerance in Chinese adults: a multicentre, randomised controlled study”​

Authors: Mei He, et al