What is milk anyway, and why is it white?
Milk is fundamental to mammals. In fact, it’s one of our defining characteristics; “mammal” comes from the same root as “mammary,” i.e. the gland that produces milk.
It is composed of water, butterfat globules (the white, “milky” part) plus carbohydrates, proteins, vitamins and minerals, especially calcium, B vitamins. With carbs, protein, fat and micronutrients, it’s the perfect cocktail for a young mammal to grow and survive, and an excellent pan-nutritional food for adult humans.
Whole or skimmed?
Low fat or skimmed milk (in which the fat content has been separated and “skimmed” from the solution) has been marketed as a sort of diet milk, with fewer calories and fats.
However, whole milk is not exactly swimming in fat to begin with. It usually has 3.5 to 4 percent fat content. (Even the fattiest milks, from, for example, Jersey cattle, only have around 5 percent fat content.) But fat (like protein and carbohydrates) is a necessary macronutrient, and it helps the body absorb fat-soluble vitamin A and D, which means skimmed milk may actually provide fewer of those vitamins though the content is technically the same.
Furthermore, new research suggests fat has wrongly taken the blame for obesity and heart disease. Sugar is a much bigger culprit, and it is often added to low fat milk to make it taste better, which might be one reason why children who grow up drinking skimmed milk actually seem to be more obese, some studies suggest.
Is it OK to drink skimmed milk if I am lactose intolerant?
Lactose, or milk sugar, is broken down by lactase enzymes in the gut, which can lead to a range of symptoms such as bloating, gas and diarrhoea for people whose do not produce enough lactase. But lactose, also called milk sugar, is contained among the milk’s carbohydrates, not fats, which remains after skimming. (That is why lactose intolerant people do not necessarily have problems eating butter.)
Worse, lactose intolerance is also far more common than people think. Around 90 percent of people of East Asian descent are lactose intolerant to some degree, and 65 percent of humans in general.
Interestingly, only around five percent of Northern Europeans (with a long culinary history of unfermented milk products, Heidi style) are lactose intolerant.
Pasteurised or unpasteurised?
Milk does not last long, and before the wide use of pasteurisation (treating milk with heat to kill microbes) in the 20th century, dairy cows were often kept as close as possible to urban areas to allow the milk to be consumed before disease microbes had a chance to mature.
Nowadays, pasteurisation is what allows a jug of milk to remain drinkable for weeks on a supermarket refrigerator aisle.
But a new trend from naturalists, local food advocates and, apparently, Gwyneth Paltrow encourages drinking unpasteurised, a.k.a. “raw,” milk, touting its rich, varied flavour and claiming that the pasteurisation process eliminates benign probiotic microbes that help with digestion and gut health.
The jury is still out on the probiotic issue, but it is true that unpasteurised milk does have a stronger flavour and richer consistency than pasteurised milk. But the United States CDC strongly recommends against drinking unpasteurised milk, detailing the many horrible diseases that can be transmitted even by the most hygienically-produced local dairies, most commonly affecting children.
Therefore, unless your milk was literally obtained this morning from your own cow, do the smart thing and make sure it’s pasteurised.
Buttermilk is what remains after the butterfat has been separated from regular milk. Thus, despite the name, buttermilk actually contains less fat, carbohydrates and overall calories than regular milk. But again, milk fat is good fat, and buttermilk’s somewhat sour taste makes it less desirable for drinking.
On the other hand, buttermilk is high in protein and benign microbes (similar to yogurt) which makes it excellent for baking.
Cow or goat? Or buffalo?
All mammals produce milk, but the milks of high-producing cows, goats, sheep, camels and other “dairy animals” are the most widely consumed.
When Americans say “milk” they probably mean cow’s milk (the US leads the world in cow dairy products), but India is the world’s top milk producer overall, and the majority of it comes from buffalos.
So what’s the difference between the milk of our various four-footed friends? In terms of taste, not a whole lot. Fans of goat’s milk, for example, often report a sweeter, “goat-ier” taste to goat’s milk, although that may simply be due to different pasteurisation processes.
However, the chemical consistency of different milks (the butterfat globules are smaller in goat’s milk) makes for a bigger difference in milk-derived products such as cheese and yogurt.