Ingenious: a new podcast bringing research to life

If you were born in New Zealand, you probably grew up thinking of milk as a superfood, a view likely promoted by everyone from your mum to the advertising pumped out by New Zealand’s dairy food giants.    

But if you are a Kiwi of non-Pākehā heritage, you might have noticed something else – drinking milk, particularly a lot of milk, doesn’t make you feel great.   

The first episode of Ingenious explores the astonishing fact that lactose intolerance affects almost 70 percent of the world’s adult population – and describes how evolution, genetics and culture have shaped humanity’s relationship with dairy.  

Hosted by Nikki Mandow, an award-winning journalist and podcast host now working at the University of Auckland, Ingenious will tell stories of the groundbreaking research and mind-expanding ideas coming from the University, and hear from the people behind those ideas about the impact of their work on the world – and on our lives. 

To introduce Ingenious to as wide an audience as possible, the University has teamed up with leading independent and award-winning news media site Newsroom.co.nz to host and support the podcast.  

Other episodes in season one include ‘Is space junk out of control?’, ‘The digital crash dummies out to revolutionise our health’ and ‘Could a 2500-year-old idea fix democracy?’ 

Mandow says launching the series with the topic of lactose intolerance was a no-brainer, as the problem impacts so many people, but the science is not well understood.   

“The symptoms of lactose intolerance vary between people, but can include gas, bloating, pain, nausea and diarrhea. But astonishingly, given the story we hear about dairy, research into the gut shows intolerance is actually the normal human reaction.”     

But what about babies? Surely pretty much all of us start life drinking milk – mums’ milk or formula?  Mandow talked to Clare Wall, Professor of Nutrition and Dietetics and head of the School of Medical Sciences at the University of Auckland. 

“Babies have no problem digesting lactose because they produce enough of the enzyme lactase to be able to break it down so it can be absorbed and utilised in the body,” Wall says.   

But what traditionally happened with humans (and other mammals) was that as babies started to eat solid food and became less dependent on human milk, the requirement for lactase diminished and so their bodies produced less and less of the enzyme.   

“In that case, when you start drinking milk with lactose in it, you can’t break down that lactose and absorb it, so it goes into the large bowel undigested. And the lactose starts to ferment and produces a lot of gas,” Wall says.    

For these lactose intolerant people, that means a distended tummy, abdominal pain, wind, and sometimes diarrhea and even vomiting.    

Thousands of years ago that didn’t matter – humans didn’t drink milk; they ate meat and plants.  But somewhere around 5,000 to 8,000 years ago some people in northwestern Europe and a few African, Middle Eastern and Southern Asian communities developed a genetic mutation. Instead of lactase production switching off after babies were weaned, the children developed a ‘lactase-persistent gene’ which allowed them to continue to produce lactase into adulthood.  

And because milk is actually pretty good for you (if it doesn’t make you sick), particularly in times of famine, scientists speculate this lactase-persistent gene was useful to the humans that had it.  So natural selection meant the genetic mutation became more widespread.  

“I have seen some other quite interesting evolutionary aspects, where scientists feel it was advantageous to be able to drink cow's milk, because it also protected people from some diseases,” Clare Wall says.

“Cows got things like anthrax, or cryptosporidium and some other diseases as well, so drinking cows’ milk provided humans with a little bit of immunity against those diseases.”  

It was mostly white Northern Europeans who ended up with that cunning milk-friendly gene, and so were able to happily consume dairy products.   

And these white people were colonisers. They went to the US and Australia and New Zealand and brought their lactase-persistent tummies – and their love of dairy – with them   Farmers built up herds of cows, and milk was promoted as a superfood.

But experts estimate almost 70 percent of the world’s population has what’s known as lactose malabsorption, a reduced ability to absorb lactose.  That includes most New Zealanders of Māori, Pacific, Asian, South American and African heritage.  

Listen to the Ingenious podcast to find out more about lactose intolerance, including why some people who aren’t lactose intolerant still can’t drink milk, and what scientists are doing to try to help.