The question is prevalent among the carnivore, paleo and keto communities and is definitely relevant to anyone else that eats dairy.

You may have heard that milk is healthy. It’s a great source of calcium that keeps your bones and teeth strong. Or you may have heard that it’s unhealthy. And that full fat cream, butter, and cheeses make you fat. But these are all staples on a ketogenic diet resulting in confusion about what exactly to do.

With a Carnivore or meat-based diet there is even more confusion. Dairy comes from an animal so it’s approved. But at the heart of a meat-centered nutrition plan is eating in a way that is congruent with how humans are designed to eat, and dairy would not have been in the human diet until the Agricultural Revolution when humans first domesticated animals.

Within the last 7,000 years some humans adapted to eating dairy by developing a degree of lactase tolerance. As babies and adolescents, humans have a gene that encodes for the lactase enzyme which breaks down lactose (milk sugar). Through most of human history, this gene would “turn off” after infancy. Thus, all adult humans were naturally “lactose intolerant.” However, thanks to a mutation that kept this gene “on” (to some degree) throughout adulthood, lactase tolerance started to spread.

Is dairy truly a “natural” food?

At this stage it becomes important to stop, rewind, and remember what dairy is meant for.

Dairy consumption is meant to grow a baby mammal into a big mammal.

A calf into a cow. A kid into a goat. A lamb into a sheep.

In order to do this, it is loaded with energy – fat, carbs, and sugars. It is also loaded with vitamins, minerals and growth factors. Human breast milk is similar as it is designed to supply a baby with what it needs to grow a lot and quickly.

However, cow milk and human milk are not the same.

Important Dairy Considerations

Milk Sugar – Lactose

If you are white, with European ancestry, you may have been led to believe that lactose intolerance is an uncommon genetic mutation. In fact, lactose intolerance is the normal, and those who are lactose tolerant, are the people who, in reality have the genetic mutation.

Lactose is the sugar in milk. In order to digest it, you need a special enzyme called lactase. As babies you have this enzyme. However, throughout human history the gene that controls lactase production “turns off” between the ages of 2 and 5. This corresponds with the weening of a baby off breast milk. Traditionally, around this time, humans lost the ability to produce lactase, and thus all humans (besides children) were lactose intolerant.

That was until about 10,000 years ago.

With the domestication of animals, the easy energy from diary provided a large selective advantage from a survival perspective. A genetic mutation called the LP allele that prevented the lactase gene from “turning off” began to become more prevalent. Adults with this mutation could now retain the ability to make lactase. Because of the selective advantage “lactase persistence” spread throughout Europe.

In the modern world, 2 out of 3 people are still lactose intolerant, meaning they still lose the ability to produce lactase. If these people consume lactose it passes through their GI tract and cannot get broken down. The lactose reaches the large intestines where bacteria ferment it, releasing lactic acid and gases. This results in feeling bloated and suffering from pains and gases.

There is a spectrum of lactose tolerance. Many people still lose the complete ability to make any lactase at all and others can make enough to digest up to 90% or so of the lactose they eat. And then there are people in between on this spectrum.

Milk Protein – Casein

Besides the varying ability to digest lactose, milk proteins – casein and whey – can be problematic for many people. For those who have trouble with dairy, that is not from lactose intolerance, it is the milk proteins creating the challenges.

Casein is a thick and sticky protein that takes digestive enzymes longer to break down. This is why it is referred to as a “slow-release” protein.

Cow milk has about 4 times more casein than human milk. This casein is also not structurally the same. Cows have a form of casein called alpha S1 casein whereas human breast milk is beta casein. This alpha S1 form of casein is the most common cause of milk protein allergies.

Cows stomachs are different from human stomachs. Cows also a special enzyme called rennet designed to break up big clumps of casein. Humans do not have rennet and many people have a hard time digesting large amount of casein.

Milk Protein – Whey

Whey is way easier to digest than casein, but, again, cow whey is different from human whey.

A problem with whey proteins in milk is that it causes insulin to rise similar to that of pure sugar. However, it doesn’t cause blood sugar to spike. This combination can destabilize blood glucose (hypoglycemia) and hormone levels that lead to cravings as well as mood swings and fatigue.

Whey also signals the body’s Growth Hormone (GH) to rise. Together with casein which signals IGF-1, you get a combination of hormone production that mimics that of puberty, fueling large amounts of growth.  This may be seen as a beneficial thing for a bodybuilder to supplement with after a workout, but perhaps not such a good thing to be stimulating on a regular basis throughout life…or for the population in general.

Addiction, Acne, and Absorption

Besides the digestion of milk sugars and the potential adverse impact of milk proteins, dairy can play a role in being addictive, causing acne, and deficiency in iron.

·       Milk peptides may have natural opioid properties which can make dairy seem addictive and sedating. Many people experience that feeling of not being able to stop with simply one small piece of cheese!!!!

·       A growth factor called betacellulin that can lead to acne through overproduction of sebum – the natural skin oils.

·       Pediatricians advise parents not to feed their baby cow’s milk for the 1st year because of the risk of developing an iron deficiency. The milk could interference with iron absorption and/or damage to GI tract.

The Need For Calcium

Calcium absolutely has its necessary place in the human diet. However, its role in bone health is not as direct as you may have been led to believe.

North Americans are a notable example as they eat more dairy than almost any other country and have higher rates of osteoporosis. There is also a lack of evidence that dairy or calcium supplements strengthen bones or protects from osteoporosis. In fact, vitamin D seems more critical.

 Should You Eat Dairy

Humans are designed to eat human breast milk as infants. Throughout history young humans are weaned off this milk which corresponded with the loss of the ability to digest lactose.

During the Agricultural Revolution, when animals were first domesticated, humans began to incorporate dairy into the diet for the first time. At that time methods were developed to remove as much lactose as possible. Then through a genetic mutation, humans began to retain the ability to digest lactose in varying degrees into adulthood however this was selective and 2/3 of the world still cannot effectively digest this milk sugar.

Cow’s milk, designed to grow a baby cow into a big cow, and is not the same as human milk. Certain incompatibilities, especially in milk proteins, can cause issues. The growth factors, while potentially beneficial in building muscle and fueling growth, may not be the best idea to stimulate day-in-and-day-out for long term health.

My guess is that those tolerant to lactose and without noticeable reactions to the milk proteins are fine to incorporate some dairy into the diet. It probably makes sense for bodybuilders, but less so for the general public.

In my personal experience I have found that most people feel far better when dairy is removed and/or limited. What could it hurt to do a test, eliminate dairy for a month, and then try it back in and see for yourself.