Many of us grew up hearing different advice about milk. Over the years, marketing and trends have told parents and consumers what is “healthy”. From skim milk being better than whole milk, to lactose-free dairy being essential, to probiotic drinks like kefir becoming a sudden health fad. These trends often change with new information (or new marketing campaigns). For instance, kefir’s benefits have recently been in the spotlight, with sweet-flavored kefir drinks now available in stores. Yet few people explored the traditional origins of kefir or realized that authentic kefir isn’t meant to be sugary. This shows how easily a product can be labeled “healthy” just to boost sales. We need to scrutinize health claims and examine actual research, particularly when it comes to something as familiar as milk.
One claim that has gained attention is “adults should not drink milk”. Some suggest that grown-ups cannot digest milk like kids do. And that continuing to drink whole milk beyond childhood is unnecessary or even harmful to adult health. In this article, we examine whether there is any truth to this claim. Can adults drink whole milk without issues? Is milk only problematic because of lactose, or are there other factors? We’ll dive into the science of lactose intolerance, how age and genetics affect milk digestion, and whether avoiding dairy can cause intolerance.
We’ll also compare regular A1 milk to A2 milk (found in certain cows, and naturally in goat and sheep milk). To see if the type of milk protein makes a difference. In the end, we’ll highlight the benefits of sheep milk – a rich source of A2 milk – and why we at Secret Lands Farm choose to raise sheep for the healthiest milk. Let’s find out if adults can keep enjoying milk and how to do it in the healthiest way.
Can Adults Drink Whole Milk?
The short answer is yes – many adults can and do drink whole milk. As long as they don’t have an intolerance or allergy. There is no official guideline that says “adults must stop drinking milk.” In fact, national dietary recommendations in countries like the United States still include milk as part of a healthy diet for adults. U.S. guidelines have traditionally suggested about three servings of dairy per day for adolescents and adults. This implies that, from an official standpoint, milk is considered safe and nutritious for grown-ups. There is no confirmed research saying that natural whole milk (including whole A2 milk) is inherently harmful to adults. Recent studies have not identified any unique risks from consuming A2 milk specifically. In other words, if you tolerate dairy, drinking a glass of milk in adulthood is generally fine.
Milk in Balance, Not Excess
However, moderation is essential. Milk is a rich food, and drinking excessive amounts might have downsides. Some nutrition experts point out that while milk provides calcium and protein, it is not an essential dietary requirement for adults. You can get those nutrients from other foods if you choose. They also caution that very high dairy intake (several glasses of milk a day for many years) hasn’t proven extra benefits for adult health. For example, one review noted that countries with the highest milk consumption also had the highest rates of hip fractures. Suggesting that more milk didn’t equal stronger bones in adults.
The same researchers observed that drinking milk excessively might be linked to certain health risks. Like a greater risk of prostate or endometrial cancer. However, this is based on observational data. These findings don’t mean milk is “toxic”. Instead, they suggest there’s no need to force down vast quantities of milk in the name of health. Adults can consider milk an optional part of the diet. It can be a convenient source of nutrients, but it’s not the only source.
Do Adults Need to Drink Milk?
In truth, adults do not need to drink milk every day if they get enough nutrition elsewhere. Milk has long been touted as an important source of calcium, vitamin D, and protein for growing children. But once we’re grown, a balanced diet can provide those nutrients via other foods like leafy greens, nuts, seeds, beans, fortified plant milks, etc. Harvard nutrition experts note that dairy is optional for most adults and that other calcium sources (such as leafy greens, tofu, or fortified juices) can fill the gap if one doesn’t drink milk. So if you don’t like milk or it doesn’t agree with you, you can absolutely have a healthy diet without it.
On the other hand, if you do enjoy milk and tolerate it well, you can undoubtedly keep drinking it in moderation. A glass of whole milk provides a host of nutrients – not just calcium and vitamin D, but also high-quality protein, vitamin B12, riboflavin (B2), phosphorus, and potassium. Whole milk does contain fat (around 3.5% milkfat), much of it saturated fat. Current guidelines suggest choosing low-fat dairy to limit saturated fat, but research is ongoing about whole milk’s effects. The key is moderation: a cup or two per day as part of a balanced diet is generally considered fine for most healthy adults. It will supply valuable nutrients and calories for energy. Just be mindful if you add milk on top of an already high-calorie diet – balance is everything.
Is Too Much Milk Bad for Adults?
“Too much” of anything can be a problem, and milk is no exception. Drinking enormous quantities of milk daily (for instance, several tall glasses every single day) may lead to issues over time. High milk intake means high calorie and high saturated fat intake, which could contribute to weight gain or elevated cholesterol in some people. Excess calcium from dairy (while rare) has been speculated to possibly contribute to specific health issues, as mentioned earlier (like prostate cancer risk), though cause-and-effect isn’t proven. Also, if you fill up on milk, you might be displacing other foods in your diet, potentially leading to less fiber or other nutrients.
The Right Amount of Dairy for Adults
Most evidence suggests that moderate consumption is key. One or two servings of milk or dairy a day is generally not associated with harm in healthy individuals, and can be part of a balanced diet. In fact, some studies even find neutral or slightly beneficial effects of dairy on heart health and weight, but results are mixed. Problems seem to arise at very high intakes or if you have specific sensitivities. So, adults should feel comfortable enjoying milk daily in reasonable amounts if they like. But drinking a litre of milk every day “just because” isn’t necessary and might be counterproductive. Always listen to your body and follow any personal medical advice. If you notice unwanted weight gain or digestive discomfort, consider adjusting how much milk you drink.
Finally, consider what type of milk you consume. Whole milk is creamy and nutritious, but it has more calories and fat. Some adults prefer plant-based milks (soy, almond, etc.), which can be alternatives, though they have different nutrition profiles. We’ll discuss A2 milk and sheep milk later as well – these are options that may offer better digestibility for some adults. In short, adults can drink milk, but they don’t have to, and if they do, it’s wise to consume it in moderation rather than in excess.
Lactose Intolerance: Does Age Make a Difference?
If there’s one big reason people say “adults shouldn’t drink milk,” it’s lactose intolerance. Lactose intolerance is the inability to fully digest lactose, the natural sugar in milk, due to low levels of the enzyme lactase in the intestine. Lactose intolerance is indeed much more common in adults than in young children. But this isn’t because of age alone. It’s mostly about genetics and whether your body “turns off” lactase production after infancy.
Humans are actually born with the ability to digest lactose because baby mammals need to digest their mother’s milk. Healthy infants produce plenty of lactase enzyme in the small intestine. In most mammals (and many humans), lactase production starts to decline after the weaning period, when milk is no longer a regular part of the diet. Historically, our ancient ancestors didn’t drink milk after early childhood, so it was normal for lactase to shut down by the time a child grew out of the breastfeeding/toddler stage. For the majority of the world’s population, this is precisely what happens. By the time they reach later childhood or adolescence, their lactase enzyme levels drop dramatically. And they become lactose malabsorbers (unable to digest large amounts of lactose). This genetically programmed drop in lactase is often referred to as lactase non-persistence or adult-type hypolactasia.
It’s in Your Genes, Not Your Age
It’s estimated that around 65–70% of adults worldwide have some degree of lactose intolerance due to lactase non-persistence. The timing can vary – some people begin losing lactase as early as 2-5 years old, while others don’t notice issues until their teens or adulthood. On the other hand, about 30–35% of people inherit a genetic trait that keeps the lactase enzyme “on” throughout life. This trait is called lactase persistence, and it evolved in populations that traditionally consumed a lot of animal milk.
For example, groups with a long history of dairy farming (like Northern Europeans, or certain African and Middle Eastern herding cultures) have a high prevalence of lactase persistence. In Sweden or Denmark, the majority of adults can digest lactose just fine, whereas in East Asia or West Africa, the majority of adults are lactose intolerant. Your genes largely determine this, not your calendar age. However, age is when the symptoms show up if you don’t have the persistence gene.
So, lactose sensitivity does increase with age for many people, but only because their genetics program the lactase enzyme to decline after infancy. If you have the genes to keep producing lactase, you can drink milk at 30, 50, or 80 years old with no issues. But if you don’t have those genes, you might start noticing discomfort from milk in childhood or later, as your lactase levels drop. It’s not that milk is inherently bad for adults. It’s that not all adults have the enzyme to digest the milk sugar.
What Causes Lactose Intolerance?
The primary cause is genetic. As mentioned, most humans are born with the gene for lactase, but a mutation (change) in our DNA is required for that gene to remain active lifelong. Only those who inherited this mutation (lactase-persistence allele) from their parents will maintain high lactase into adulthood. Everyone else will see a reduction in lactase after the weaning years. From an evolutionary perspective, the lactase-persistence mutation spread in communities that domesticated cattle, goats, or sheep for milk – having the ability to digest milk gave those people a nutritional advantage (extra calories and calcium/protein) in times of need. This positive selection explains why today we see significant regional differences in lactose tolerance.
Besides genetics, there are other forms of lactose intolerance too. Secondary lactose intolerance can occur at any age if the small intestine is damaged or affected by illness. For example, severe gastroenteritis, untreated celiac disease, Crohn’s disease, or other intestinal issues can temporarily reduce lactase production. In those cases, treating the underlying condition can sometimes restore lactose tolerance.
Lactose Intolerance Symptoms
When an adult with low lactase drinks a lot of milk, the undigested lactose travels to the colon where gut bacteria ferment it. This fermentation produces gas and pulls in water, which leads to the classic symptoms. Common lactose intolerance symptoms in adults include:
- Bloating and abdominal pain (from gas production in the gut)
- Excess gas and belching
- Cramping sensations in the lower belly
- Diarrhea or loose stool (as lactose draws water into the intestines)
- Nausea (in some cases)
These symptoms typically start 30 minutes to 2 hours after consuming a high-lactose meal. The severity of symptoms can vary widely from person to person. Some people with lactose intolerance might feel sick after just one glass of milk, while others can drink a latte or have cheese and feel okay.
Finding Your Dairy Tolerance
Importantly, lactose intolerance is dose-dependent – many lactose-intolerant adults can handle a small amount of lactose without trouble. Most people with lactase non-persistence retain some enzyme activity (it’s not usually zero), so they might be able to enjoy a small serving of milk or certain dairy products with minimal or no symptom. Fresh milk tends to have the most lactose, whereas aged cheeses and yogurt have much less (fermentation by bacteria breaks down lactose).
This is why someone might say “I can’t drink a glass of milk, but I can eat a cup of yogurt or a piece of cheddar just fine.” It’s not all-or-nothing – lactose intolerance for many adults is about finding your personal threshold. If you consume dairy in moderate portions or alongside other food, you might experience very mild or no symptoms. But if you chug a large milkshake on an empty stomach, you could be in for GI distress if you’re sensitive.
It’s also worth noting that lactose intolerance is not the same as a milk allergy. If you’re lactose intolerant, your body cannot digest the milk sugar, leading to GI symptoms, but your immune system isn’t reacting. A milk allergy, on the other hand, is an immune reaction to milk proteins (casein or whey) and can cause hives, respiratory issues, or even severe allergic reactions. Milk allergy is more common in children and is often outgrown. It’s relatively rare in adults. Here we are focusing on intolerance (enzyme-related), which is much more common.
Conclusion: Enjoying Milk in Adulthood – Listen to Your Body
So, can adults drink milk? Absolutely – if you enjoy it and it agrees with you, there’s no research-backed reason that all adults must avoid milk. The notion that adults “cannot digest milk at all” is a half-truth; it’s correct that many adults (around 2 in 3 worldwide) don’t digest lactose well, but a significant number (especially those from dairy-consuming cultures) retain the ability to digest milk sugar and can drink milk daily without issues. Even if you are lactose intolerant, you may not need to swear off dairy entirely – you might tolerate small amounts, especially of certain products, and your gut can adapt to improve your tolerance over time.
The key takeaways for adult milk consumption are:
- Know your own tolerance: If milk gives you stomach problems, identify whether it’s lactose intolerance or perhaps an issue with A1 protein. You can experiment with A2 milk (or goat/sheep milk) to see which you tolerate. Many people with “dairy intolerance” find a solution in either using lactase drops/pills for lactose or switching to A2 dairy sources. If you have a true milk allergy, then milk (including sheep milk) won’t be suitable – but lactose intolerance can often be managed.
- Moderation and quality: Include milk as part of a balanced diet, not as a singular magic food. One or two servings a day can provide benefits, but you don’t need to force yourself to drink milk if you don’t like it. Ensure the rest of your diet covers your nutritional needs. When you do consume dairy, opt for high-quality, natural sources (like whole milk, yogurts without tons of added sugar, or cheeses) to get the most benefits. A2 milk or sheep/goat milk can be a great quality choice.
- Gradual changes: If you decide to incorporate a new type of milk (say, switching from regular cow milk to sheep milk) or reintroduce dairy after a break, go slowly. Your digestive system may need a little time to adjust. For example, start with a half-cup of sheep milk or a small amount of cheese and see how you feel. Gradually increase as tolerated. As we noted, it took time for intolerance to develop, and it can take some time to reverse it. Be patient with your gut.
- Health is individual: While we provide general guidance, everyone’s body is unique. Some adults thrive on dairy, others do better without it. The goal is to stay healthy by giving your body what it needs. If that includes milk, great! If you prefer alternatives, that’s fine too.
Rethink Milk Myths
At the end of the day, the idea that “adults can’t drink milk” is not a hard rule – it depends on the person. Whole natural A2 milk (like sheep milk) is not officially confirmed to harm adults; in fact, it’s quite the opposite, offering an easily digestible, nutrient-rich option. For those who have shied away from milk due to digestive issues, exploring sheep milk’s benefits could open up a new world of nutrition. We encourage you to read your labels (know whether that milk is A1 or A2, lactose-free or not, etc.), do a bit of self-experimentation within safe limits, and make informed choices. You might discover you can enjoy dairy again by choosing the right type.
Stay healthy and don’t hesitate to question nutritional “facts” that might just be marketing in disguise. By relying on up-to-date research and listening to your body’s signals, you can find the diet that’s right for you. Stay healthy with Secret Lands Farm, and if you’re curious about sheep milk, we’ll be happy to be part of your journey to enjoyable, healthy dairy consumption!
Sources:
- Harvard T.H. Chan School of Public Health – Milk may not be necessary for most adults hsph.harvard.edu
- MedlinePlus Genetics – Lactose intolerance (LCT gene and lactase nonpersistence) medlineplus.gov
- Forsgård RA et al., Am J Clin Nutr (2019) – Lactose digestion in humans: intestinal lactase is constitutive; colonic microbiome is adaptable pmc.ncbi.nlm.nih.gov
- Medical News Today (Updated Sept 1, 2025) – A2 milk: Benefits vs. A1 milk medicalnewstoday.com
- Dairy Foods Magazine (Feb 12, 2024) – All about A2, goat and sheep milk dairyfoods.com
- Shrestha et al., Frontiers in Nutrition (2021) – Sheep vs. cow milk in lactose malabsorbers trial frontiersin.org
- Bellwether Farms FAQ – Benefits of Sheep Milk bellwetherfarms.com