Is Drinking Milk Unnatural?

I recently got a note from Diane, who was upset with me for supporting the consumption of dairy products.

“No human should be consuming milk after they've been weaned from their mother's breast,” she wrote. “It is completely unnatural. Cow’s milk is intended only for baby cows—and it’s cruel to take the milk away from the calves for whom it is clearly intended. Need calcium? Milk, which may contribute to osteoporosis and numerous other health issues, is the last place you should be getting it.”

Before I respond to Diane’s remarks, I just want to repeat something I’ve said many times before: Drinking milk is not necessary for good nutrition (or strong bones) and I completely support anyone who decides for whatever reason that they don’t want to consume it. If you’ve decided you don’t want to drink milk, I am not going to try to talk you into it.

If, on the other hand, you ask me about the benefits or risks of dairy (or any other food), I will try to give you a balanced and evidence-based answer, so that you can base your decision on good information.

I’ve certainly heard these arguments against drinking milk before. Maybe you’ve heard them too. Maybe you’ve made them! Often there is a lot of emotion involved, which can make it hard to have a productive conversation about this issue. But I’d like to try.

Although they are often all jumbled together, there are actually three completely different arguments being presented here.

1. Drinking milk is unnatural
2. Drinking milk is unhealthy
3. Drinking milk is cruel

It’s possible to accept or reject one of these arguments without accepting or rejecting them all. So, let’s consider them one by one.

1. Is Drinking Milk Unnatural?

I would submit that the natural world does not operate with intention, nor is it all that attached to a plan. In fact, some of Nature’s greatest hits are the result of random errors and unintended consequences. Nature also doesn’t care about right or wrong, or whether something is fair or ethical or cruel. All nature "cares" about is what works.

If a bird lays an egg that hatches into a baby bird, which matures and lays another egg, that works for Nature. But if that egg is stolen out of the nest by a hungry raccoon who goes on to reproduce, that works too. Nature isn’t rooting for the bird more than it is rooting for the racoon. In fact, if Nature were actually capable of rooting for anything, it would probably hope that just enough eggs would be stolen to ensure plenty of baby racoons AND plenty of baby birds.

To the extent that consuming dairy enhanced the survival and reproduction of prehistoric humans, who then committed resources to enhancing the survival and reproduction of dairy animals, the fact that humans learned to use the milk of other species has worked out pretty well for Nature. So much so that some branches of the human family evolved to continue to produce milk-digesting enzymes throughout adulthood.

The objection to things that are not natural also seems to be somewhat selective. If you are willing to switch on a light after the sun goes down, use an alarm clock to wake you up, get in a jet plane and catapult yourself across three or four time zones in a few hours, run long distances without anything chasing you, or take a vitamin pill, then you’re doing quite a few things that are arguably a lot less natural than drinking milk.

The fact is that mother's milk contains nutrients that benefit animals other than that mother's babies—and it would be unnatural for those other animals to ignore that discovery.

2. Is Drinking Milk Unhealthy?

Just about anything can be consumed in quantities (or contexts) that make it harmful. But are dairy products bad for you when they are consumed in the context of a balanced and nutritious diet? Do they cause heart disease, cancer, or other diseases?

Diane specifically mentioned a correlation between dairy consumption and osteoporosis. But just because two things occur simultaneously does not mean that one thing causes the other. In this case, there are several more likely explanations for why these populations might have higher rates of osteoporosis, including genetics, activity levels, and other aspects of diet and lifestyle.

When we compare people within these populations (instead of across them), milk and dairy consumption are associated with better bone health—which makes sense, because milk is an excellent source of absorbable calcium, vitamin D, and other nutrients that help to build strong bones.

Others have claimed that drinking milk causes breast cancer, an argument based mostly on animal or test tube studies and observations gleaned from a single highly unrepresentative population.

---

As I discussed in my episode on diet and breast cancer, dozens of studies—several of them involving thousands of human subjects—have investigated the possible relationship between dairy consumption and breast cancer. Researchers have failed to show a consistent link between dairy consumption and breast cancer. (In a few of the studies, dairy consumption was actually linked to a slight reduction of risk.)

If you are trying to build a case against milk or dairy, you can sift through the scientific literature and find individual studies that suggest a link between dairy intake and various diseases. Look a bit further and you’re likely to find other studies finding that dairy consumption reduces the risk of those same diseases. (You’ll find lots of articles in the Nutrition Diva archives taking a closer look at many of these concerns.)

See also: Does Milk Increase Ovarian Cancer Risk?  and How Does Dairy Affect Your Hormone Levels?

When you step back and look at the literature as a whole—not to mention the evolutionary history of our species—it is hard to make a case that dairy products are uniquely harmful to humans. You can build a healthy diet with or without dairy products. And, of course, the opposite is also true.

See also How Much Dairy Is Too Much?

Whether the nutritional (or culinary) benefits outweigh the potential risks is going to come down to individual judgment, and that will probably be heavily influenced by which sources of information you choose to consider. It may also depend on your individual health concerns and priorities. Eliminating milk from your diet may clear up your acne but reduce your chances of getting pregnant, for example. Whatever you choose, you’ll have my full support. (My support, however, does not extend to tolerating false or misleading information.)

3. Is Drinking Milk Cruel?

The third argument against consuming dairy is that dairy farming is cruel or unethical, which is a moral or philosophical question. I am not a professional ethicist—but even the experts struggle with this.

Some might argue that the inalienable right to life, liberty, and the pursuit of happiness is not limited to humans but extends equally to all living things, and that keeping dairy cows is morally equivalent to keeping slaves.

Others might feel that it’s OK to take a cow’s milk in exchange for providing its food and shelter, but only as long as the cows are treated well. Given the limitations of cross-species communication (not to mention intra-species communication), there’s a lot of room for debate over what constitutes a good life for a cow. Come to think of it, there’s a fair amount of debate over what’s a good life for humans!

We all have to come to our own conclusions on this question. And, once again, this will probably be heavily influenced by what sources of information we consider.

Personally, I welcome the increased focus on animal welfare and the mounting demand for more humane treatment of agricultural animals. For example, there is now a growing movement in the dairy industry to keep calves with the mother cows until they are weaned. This certainly seems to be a step in the right direction in terms of balancing the rights and welfare of the cows and the humans who benefit (either financially or nutritionally) from the milk that the cows produce.

To the extent that I consume animal products, I go out of my way to identify and support producers who treat their livestock well. I recognize that others believe strongly that there is no way to consume animal products without cruelty.

But if you want to convince others that drinking milk is morally indefensible, I’d stay away from arguments about it being unnatural to drink milk, because that logic doesn’t hold up very well under scrutiny. Similarly, assertions that milk is unhealthy or causes disease are easy to refute (or at least counter) with hard evidence. Both of these flawed arguments end up diverting attention away from the important conversation that can and should be had about whether using animals for food is—or can be made—ethically acceptable.

As always, I look forward to hearing your thoughts.