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Over the last decade, milk has become a bit controversial.


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Some people say it's a necessary and nutritious food, vital for healthy bones,


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but others say it can cause cancer and lead to an early death.


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So, who's right?


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And why are we drinking it anyway?


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[Intro music]


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Milk is the basis of every mammal's diet after birth,


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when our digestive systems are immature and small.


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Basically, it's power food to kick-start our bodies and help us grow.


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Milk is rich in fat, vitamins, minerals, and milk-sugar: lactose.


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On top of that, for a while after birth, it also contains antibodies and proteins


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that protect us from infections and regulate our immune system.


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But it's a lot of effort for mothers to produce.


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Eventually, humans stop drinking mother's milk


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and transition to the diet of their parents.


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This is how it's been for thousands of years.


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Until about eleven thousand years ago,


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when our ancestors settled down in the first agricultural communities.


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Soon, they domesticated the first dairy animals:


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goats, sheep, and cattle.


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They found that dairy animals are able to eat useless and abundant stuff


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and turn it into nutritious and tasty food.


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This made a huge difference in terms of survival,


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especially in hard times.


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So groups that had milk available had an evolutionary advantage.


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And through natural selection,


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it changed the genes of communities who consumed a lot of it.


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This adaptation has to do with a specialized enzyme: lactase.


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Babies have a lot of it in their system,


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so they can break down the milk-sugar lactose and digest milk easily.


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But the older we grow, the fewer lactase enzymes our body produces.


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Worldwide, about 65% of the population do not have the enzyme after infancy,


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which means they are not able to digest more than about 150 milliliters each day.


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This lactose intolerance is not spread evenly around the world, though.


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In some East Asian communities, for example, it's up to 90%.


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In Northern Europe and North America, the rates are the lowest overall.


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There are probably a few reasons for this uneven distribution.


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The trait was first introduced by random mutation,


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which happened independently of each other in a few populations.


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The fact that farming replaced hunting and gathering more and more


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created natural-selection pressure.


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People who were able to digest lactose had more foods at hand,


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which was an advantage.


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The migration of dairy farmers to the north then spread it further, which probably pushed back populations there that didn't have the trait.


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Okay, but if milk has been a valuable part of our diet for thousands of years, why is it so controversial?


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There are a number of claims regarding the negative and positive health effects of milk.


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The negative ones cover a wide variety,


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from brittle bones to cancer, and cardiovascular diseases to intolerance and allergies.


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So, how do they hold up?


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Some older studies found a connection between milk and a high risk of breast, colon, and prostate cancer


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But meta analyses found no impact on your cancer risk.


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On the contrary, the calcium in milk might even have a protective effect against colon cancer.


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Although this could be calcium in general, it's not clear milk plays a role in this effect.


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Only studies on prostate cancer showed an increased risk for people who consumed more than one and a quarter liters of milk a day.


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But again, the association is inconsistent and other studies don't find any effects.


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We discuss these studies in more detail in our sources document. All in all, the research seems to show that if you drink between


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100 to 250 milliliters of milk per day, cancer is not a concern.


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Similarly, meta-analyses could not find any impact from milk or dairy products on


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your risk of heart disease, stroke, or your total mortality.


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Some studies even suggested that high blood pressure might be rarer in people who eat a lot of dairy,


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although the evidence is not strong enough to claim this with confidence.


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The case gets more complicated though when we look at bones.


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A number of studies found neither positive nor negative effects for adults.


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What most people worry most about though are harmful amounts of pesticides, antibiotics, or hormones.


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There are hormones in milk, but only in very low concentrations.


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For example to get the same amount of hormones as from the pill,


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you'd need to drink about 5000 litres of milk,


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and even if you did, most hormones would be destroyed by your digestive system


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before they could affect you,


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which is the reason why so much medication is coated to protect it from our digestion.


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For pesticides and antibiotics,


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there are regulations in most parts of the world that only allow completely harmless amounts.


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Milk that surpasses these thresholds is not allowed to go on the shelf.


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So there's nothing in particular to worry about.


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Besides allergies and those suffering from lactose intolerances,


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the best known negative effects of milk are probably acne and general discomfort after drinking milk or eating dairy products,


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and here the effects are very real.


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For example, skimmed milk has been found to statistically increase the rate of acne by 24%.


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Allergies against milk products are especially prevalent among children, with one in 18 kids in Germany suffering from them.


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In general, these allergies tend to get better or disappear as they grow older though.


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Okay. Is milk healthy then?


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Milk, no matter if it comes from mothers, cows, sheep, goats, or camels is a nutrient-dense food.


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It contains all necessary macronutrients and many micronutrients.


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Especially in regions where people struggle to get enough calories,


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milk can contribute to a healthy life and lower child mortality.


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For those living in the developed world, in general


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milk is not harmful if you are not allergic or intolerant to it.


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Especially for children, it's a good way to get large amounts of calcium


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and for vegetarians, it's a good source of vitamin b12 and B vitamins in general.


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This does not mean there are not other alternatives with the same effect. You do not need to drink milk to be healthy


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Milk is also definitely not a substitute for water.


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Milk is power food, and the additional calories from drinking a lot of it on a regular basis can contribute to being overweight.


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Especially flavored milk or chocolate milk is more comparable to beverages like lemonade than a healthy snack, and there's another thing to consider.


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Milk production has a significant impact on the global climate.


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About 33 percent of cropland is used to feed grazing animals including dairy cattle


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Even though the carbon footprint of dairy products has declined since 1990,


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Dairy production is still responsible for 3 percent of all greenhouse gas emissions,


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even more than all airplanes combined.


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Milk is a huge industry and sadly, most of its production in factory farms causes incredible suffering.


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Cows are impregnated over and over, separated from their young shortly after birth,


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and slaughtered once their tortured bodies are not productive anymore.


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We can't ignore that much of the milk we consume stems from an industry


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that is basically torture and contributes to climate change.


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What about plant-based milk?


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In terms of protein levels and nutritional value, only soy milk can compare to cow milk.


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The others need to be artificially enriched to reach similar levels of vitamins and calcium.


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So they can be an alternative to milk.


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And another option might be available soon.


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Several startups have created non-animal milk


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that is nutritionally identical to dairy milk,


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for example, through fermentation by gene modified bacteria.


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This lab-grown milk can even be turned into cheese,


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something that plant based alternatives struggle with because they lack casein and whey protein,


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the key ingredients that give dairy its taste and structure.


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The environmental impact is a different story though.


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Many milk alternatives use significantly less energy, land and less water to produce


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so they have a much lower environmental impact than animal milk.


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If you want to have the lowest possible negative impact on the planet, the best choice is whatever milk alternative is regional.


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As with almost any topic milk is complicated.


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It's not harmful for the majority of the population and it's crucial for many people around the world.


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It's good, nutritious food, but also harmful to the planet and causes a lot of suffering.


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We need to decide as a society how we want to deal with these facts.


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