Why milk is weird

JC: Humans have been drinking milk for tens of thousands of years.

But for something so familiar, it's actually kind of weird.

JOHANNA: One of the weird things about milk is that most adults

are actually lactose intolerant -

they can't digest milk.

JC: Another obvious - and also kind of weird - thing

is that milk is essentially breast milk -

a liquid made by a cow or other animal to feed its young.

JOHANNA: Why did humans start drinking it in the first place?

And is it even good for us?

I'm Johanna Zetterstrom-Sharp

and I am fascinated by the cultural history of milk.

JC: And I'm JC Niala, and I'm interested in how milk

has always been about more than just nutrition.

JOHANNA: Here's five surprising things that you probably

didn't know about milk.

COW MOOS

JC: When humans began drinking milk

around 10,000 years ago, it was a digestive challenge.

Babies are born with an enzyme called lactase

that breaks down lactose, the sugars in milk.

This enables them to digest breast or, more recently, formula milk.

For most people around the world,

lactase actually wears off after infancy,

leading to lactose intolerance,

which can show up as indigestion, bloating,

cramps or diarrhoea.

But many of our ancestors still drank it.

That was because milk turned grass that animals ate

into a superfood containing fat, protein, calcium,

and other nutrients.

For people travelling with their animals

in East Africa 7,500 years ago,

milk provided a reliable meal on the move.

JOHANNA: Milk was promoted as a vital source of calcium

in the post-war period,

essential for bones, teeth and muscles.

In 1946, milk was made free

for state school children across the United Kingdom.

And it's true that milk is rich in calcium -

one glass a day gives you about a third of the calcium you need.

But, in fact, cows get their calcium from plants,

which pull it directly from the soil,

so milk is a kind of second-hand source.

And us humans, we can get calcium from lots of different sources,

like kale, figs, tofu and sardines.

JC: We may think of milk as a single uniform thing -

a cool fresh white drink, slightly sweet,

drunk from the fridge.

Large-scale dairy farming means that the milk that we buy

comes from cows with tightly controlled diets.

This ensures uniform colour, creaminess and consistency.

But milk is a shapeshifter.

Its qualities change depending on the cow, the farm,

the microbes that travel in it.

A recent study showed that if you feed cows garlic,

it reduces the gases in cows' farts, which contribute to climate change.

But the strategy hit a problem

when people realised that the milk tastes funny.

JOHANNA: Milk cartons often depict Daisy,

grazing in the sunshine, enjoying life on the farm.

But these pictures never show her calf.

And this is no coincidence.

In most commercial dairies,

calves are taken away from their mothers within a day

so that the milk can be collected for humans.

And the milk we get from the supermarket

isn't from a single farm either.

It's a mix of many different milks.

And these cows are no "Daisys".

They are animals in a highly industrialised system,

treated with antibiotics and artificial feed

to produce consistent, low-cost milk all year round.

But there are some farms - like this one -

that prioritise the welfare of the cow

and choose sustainable farming methods.

But overall, we have become so disconnected

from the food that we eat

that it's hardly surprising that a survey in the US

found that 16 million people thought

that chocolate milk came from brown cows.

COW MOOS

JC: In modern English,

there's just one widely used word to describe this - milk.

But in other languages,

like the Runyankole/Rukiga languages in Uganda,

there's a whole vocabulary used to describe its sources,

tastes and preparations.

Many languages have words to distinguish

the first milk used to feed a young calf and later milk.

You could say that when the human relationship with milk runs deep,

the language grows to match it.

JOHANNA: We may think we know milk, but what we're finding is

we don't actually know milk at all.

JC: Our ideas about milk are carefully managed

to protect an industry

that is reliant on us drinking milk in large volumes,

disconnected from the animals that produce it.

JOHANNA: Milk is good for us.

But it's not good for all of us, all of the time, in the same way.