Scientists track effects of A2 milk on gut

Currently there are no conclusive human studies that show the effects of A1 protein, which is found in regular dairy milk, on the human gut. However, the team from Alfred Health and Monash University has set out to find the truth.

Lead researcher and Director of Gastroenterology at The Alfred, Professor Peter Gibson, said it is commonly believed that the A1 protein in regular cow’s milk (which contains both A1 and A2 proteins) can cause digestive issues and in some cases cognitive issues in humans.

There is a breed of cattle farmed extensively in New Zealand which, as a result of a genetic mutation, produces milk that only contains the A2 protein.

“We are trying to determine whether there is a physiological effect on people due to the A1 protein,” Professor Gibson said.

“This is a very important study because currently A2 milk is quite controversial – nearly all the data on it have been derived from animal studies so there is no direct proof that it is more tolerable for people.”

Professor Gibson said the A1 protein produces an opioid peptide in the gut which can slow digestion in some people.

If you'd like to know more or participate in the study, contact shirley.webber@monash.edu 

The study will be conducted on 10 healthy participants and 20 participants with Irritable Bowel Syndrome (IBS). They will be required to undergo a four-week diet consuming A1-containing milk three times per day, followed by four weeks dairy free, followed by a four-week diet consuming A2 milk three times per day. The opposite order of A1 and A2 milks will be used in one half of the participants.

The participants’ intestinal health will be monitored using a Smart Pill, which is a tiny camera that is swallowed and travels through the gut – capturing data along the way.

“There are two possible outcomes we’re going to see from this trial,” Professor Gibson said.

“We’ll either see that A2 milk is superior and definitely does not have the same effects on the bowel that A1-containing milk does, otherwise we will see that there is no real difference in the bowel.”

Some people also believe A1 intolerance can cause ‘brain fog’ and other cognitive or behavioural issues, including depression. Professor Gibson said this will be measured with a simple cognitive test.

If you would like to know more or sign up to participate in the study, contact shirley.webber@monash.edu