There is SO MUCH to say about dairy. Milk and dairy products have been part of the human diet for millennia and have shaped our evolution. They are incredibly nutritious foods. They have also been surrounded by a buzz of controversy in nutrition research, as some critics suggest that it is unnatural and possibly unhealthy to consume dairy products. So what’s the truth? As always, probably somewhere in the moderate middle. Let’s review what dairy is all about and some of its nutritional qualities.
What is dairy?
As most of you probably know, “dairy” refers to milk and milk products, including foods like cheese, yogurt, cream, ice cream, and butter. Milk is made by all mammals and is meant as the first food for a newborn. Its formula is perfectly tailored to newborn animals and gives them the ability to continue developing outside of the womb.
Most of the milk consumed today is made by ruminants such as cows, sheep, and goats. These animals have the ability to digest dry grass (something we humans can’t do) and use the energy to make large amounts of milk. Milk is usually processed in large factories and is also transformed into the many dairy products we can find in grocery stores, which vary a lot from country to country.
Milk production and processing
Most of the world’s milk comes from cows, which tend to be raised and milked in large dairy farms. The milk is then processed on an industrial scale, which means that milk from many different dairy farms gets combined and processed in large plants, leading to a higher chance of contamination. This is where pasteurization comes in. Pasteurization is the process by which milk is heated to kill microbes that may be dangerous to our health. It makes milk safe for consumption and extends its shelf life, so that it can stay good for 10-18 days when refrigerated. Another process, called homogenization, is there to mix the milk’s fat thoroughly so that it doesn’t separate. This makes our milk slightly whiter and creamier, but also removes some of its flavour. Lastly, most of the milk we drink today has had some of its fat removed to make it low-fat milk, ranging from 0% to 2% fat. Some is still sold as whole milk, which has 3.5% fat. Most of the milk and milk products we can find at grocery stores have been processed in these three ways.
Raw milk
Raw milk is milk that did not undergo pasteurization and homogenization. It is not very common in North America or Europe. In the U.S. it requires a special certification and frequent inspections. In Canada, it is illegal to sell. Suffice it to say, raw milk is a risk and I do not recommend consuming it.
The health benefits of dairy
Nutrients in dairy products
As previously mentioned, milk is designed to be food for a newborn. As such, it has all of the nutrients a newborn needs to survive and grow. Of course, cow’s milk is formulated for a calf, not a human, but still it provides many essential nutrients. Cow’s milk is high in protein, vitamins and minerals, including calcium. Much of the milk found in grocery stores is also fortified with Vitamin D, which helps calcium get absorbed by the body. The only major nutrients missing from cow’s milk are iron and vitamin C.
The nutrients found in other dairy products highly depend on the product type. Some products are very high in fat, such as hard cheeses and ice cream, while others contain no fat at all. In general, most dairy products are high in protein and calcium.
Bone health
Milk and other dairy products tend to contain a lot of calcium, which is important to bone health. Many people in developed countries, especially women past menopause, experience low bone density, and this is associated with fractures. Reducing that risk has to do with maximizing the amount of bone we accrue when our bones are still developing, usually up until early adulthood. Having adequate calcium and protein in your diet during this time, as well as other important nutrients, exercise, and avoidance of smoking and excessive alcohol use, are all important to achieving strong bones.
Of course, it’s important to keep this up past early adulthood. Our bones are constantly being broken down and built up, and in general, we want a good balance between bone deconstruction and reconstruction. We can get this from exercising often and having a balanced diet throughout our lifetime. Milk can certainly be part of this diet, but there are other calcium-containing foods such as beans, nuts, tofu, and dark leafy greens that should be included. Unfortunately, just adding milk or dairy products to your diet cannot guarantee bone health.
Fermented dairy and gut health
Some dairy products are made by fermentation. Fermentation happens when bacteria in the milk begin to convert sugar into acids. These acids actually preserve the milk product while also changing its taste and consistency.
Fermented products are not only delicious, they are also good for our gut health! There is evidence that the bacteria found in some yogurts, specifically those labeled as containing probiotics, can actually protect us from other, disease-causing bacteria. These helpful bacteria secrete anti-bacterial compounds inside our intestines, which helps our immune system fight dangerous bacteria. There is evidence that these bacteria even help by lowering the production of carcinogens within our intestines! Keep in mind however, that standard yogurt, although great for you in other ways, does not provide bacteria that can survive in our digestive tracts. For that, you have to buy yogurt and other fermented products that specify that they contain probiotics.
Dairy and health controversies
Lactose intolerance
Let’s start by saying that humans are a bit weird. Of all the animals, we are the only species to continue drinking milk after being weaned from our own mother’s milk. However, this has given us a huge advantage in our growth and evolution, so I won’t be hating on this fact. It is worth noting though, that not everyone can drink milk past infancy. In fact, most people in the world (65%) have a reduced ability to digest milk, a condition called lactose intolerance. The culprit that causes issues in milk digestion is called lactose, and it is a sugar found in milk. Lactose is made up of two sugar molecules and needs to be broken down into its two constituent parts within our intestines in order to be absorbed. The thing that breaks it down is an enzyme called lactase. People with lactose intolerance have low levels of this enzyme. When these people eat dairy products that contain lactose, it doesn’t get broken down and instead passes into the large intestine, where it pulls in water (causing diarrhea) and gets metabolized by our resident gut bacteria (which produce gas). This is all around an unpleasant experience.
People with lactose intolerance can still consume dairy products if they wish. Some products, like yogurt and hard cheese, have less lactose in them so they can be consumed safely even by those who are lactose intolerant. There are also lactose-free milk and dairy products being sold in most grocery stores. These products have simply had the lactase enzyme added to them. Lastly, you could also buy lactase in pill or liquid form and take it with dairy products.
Babies and cow’s milk
Over the last few decades, the popular belief that milk is good for everyone all of the time began to be questioned. Specifically, the question of whether babies should be given cow’s milk started being scrutinized. Turns out that because cow’s milk is formulated specifically for calves and not human babies, it is actually not a good idea to give a baby cow’s milk before the age of 1. Cow’s milk contains too much protein and not enough iron and healthy fats for human babies. Giving babies cow’s milk can also trigger allergies to milk. So, it’s best to wait.
Obesity and heart health
Over the last few years, there has been some buzz in the media regarding the effects of dairy consumption on obesity and heart health. Based on the most recent research, it seems that this was overplayed.
Dairy consumption does not seem to be associated with higher body weight, and certain dairy products like yogurt may even protect from weight gain. The protein from dairy was also found to be helpful in retaining muscle mass during weight loss.
In terms of heart health, the argument goes that dairy products contain saturated fats, which we know are associated with heart disease. This much is true. However, evidence is starting to come out that the type of saturated fat (there are many kinds) as well as the food in which it is in, also have a lot to do with whether that particular food affects your health. When it comes to dairy products, apparently this makes all of the difference. It seems that although dairy products do contain high levels of saturated fats, these types of saturated fats and the other nutrients in the dairy product make it so that the fats do not affect heart health. Bottom line? It seems that dairy consumption is not associated with heart disease.
What’s the deal with butter?
Butter used to be considered a nutritional culprit. Nutritionists used to suggest to their clients to cut it out completely and replace it with margarine or plant-based oils, which are considered healthier. Nowadays, however, it seems that butter is making a comeback.
In nutritional research, butter is considered different from other dairy foods and is often not included in the statistical analysis. This is because butter is made just from milk fat and contains very few other nutrients. Research that does include butter is scarce, but the papers that exist suggest that butter intake is not associated with heart disease, diabetes, or all-cause mortality. This is why if you asked me, I’d tell you to eat butter if you like it. As always, moderation is key.
Recommendations
Interestingly, dairy is no longer included as its own food group in Canada’s Food Guide. Instead, it is placed in the “protein foods” category, with a suggestion of having a quarter of your plate made up of protein foods. This basically means that according to the food guide, you don’t necessarily need to eat a certain amount of dairy per day, and it’s considered just another protein-containing food.
But how much dairy should you eat when you do eat it? Since Canada’s Food Guide doesn’t have recommended portions anymore, I used information from the American Heart Association. They suggest serving sizes of 1 cup for milk and yogurt, and 40 grams for cheese (about the size of a matchbox). Both the American Heart Association and Canada’s Food Guide recommend choosing dairy products that are lower in fat or fat-free. They also suggest you stick to those with low sodium and sugar.
In general, I would tell you to continue eating dairy if you enjoy it. There is no need to be afraid of dairy consumption as it does not seem to be connected to any major health issues in adults. I would also recommend trying some new products! There are some great fermented products out there, like kefir, which are becoming more popular. I personally also enjoy cottage cheese and quark cheese, both of which are popular in Israel, where I grew up. Lastly, don’t feel guilty when eating hard cheeses, they are delicious and the research shows they are not bad for you. Of course, moderation is always key with everything, especially dairy products that are high in fat and calories, like cream, butter, hard cheeses, and ice cream.
Interested in some dairy-based recipes? Check out the recipes below:
References
Note: a lot of the research done on this subject is funded by the dairy industry. In my research, I tried to find articles that were not funded by the industry, as this could bias the results. However, some of the references below do have authors who received funds from the dairy industry and so there is the possibility of bias.
- American Heart Association. (2020). Suggested Servings from Each Food Group. Retrieved from https://www.heart.org/en/healthy-living/healthy-eating/eat-smart/nutrition-basics/suggested-servings-from-each-food-group.
- Givens, I. (Ed.). (2020). Milk And Dairy Foods: Their functionality in human health and disease. Elsevier Academic Press.
- Godosa, J., Tierib, M., Ghelfib, F., Tittab, L., Marventanof, S., Lafranconig, A., Gamberai, A., Alonzoj, E., Sciaccak, S., Buscemil, S., Rayc, S., Del Rioc, D., Galvanop,F., and Grossoc, G. (2019). Dairy foods and health: an umbrella review of observational studies. International Journal of Food Sciences and Nutrition, 71(2), 138–151. doi https://doi.org/10.1080/09637486.2019.1625035.
- Government of Canada. (2020). Canada’s Food Guide: Eat Protein Foods. Retrieved from https://food-guide.canada.ca/en/healthy-eating-recommendations/make-it-a-habit-to-eat-vegetables-fruit-whole-grains-and-protein-foods/eat-protein-foods.
- Josse, A. R., Atkinson, S. A., Tarnopolsky, M. A., and Phillips, S. M. (2011). Increased Consumption of Dairy Foods and Protein during Diet- and Exercise-Induced Weight Loss Promotes Fat Mass Loss and Lean Mass Gain in Overweight and Obese Premenopausal Women. The Journal of Nutrition, 141, 1626–1634. doi 10.3945/jn.111.141028.
- McGee, H. (2004). On Food and Cooking: The Science and Lore of the Kitchen. Scribner.
- OECD and FAO. (2019). Agricultural Outlook 2019-2028: Dairy and Dairy Products. Retrieved from http://www.fao.org/3/CA4076EN/CA4076EN_Chapter7_Dairy.pdf.
- Pimpin, L., Wu, J., Haskelberg, H., Del Gobbo, L., Mozaffarian, D. (2016). Is Butter Back? A Systematic Review and Meta-Analysis of Butter Consumption and Risk of Cardiovascular Disease, Diabetes, and Total Mortality. PLoS ONE 11(6). doi 10.1371/journal.pone.0158118.
- Procon. (2020). Historical Timeline. Retrieved from https://milk.procon.org/historical-timeline/.
- Rozenberg, S., Body, J. J., Bruyere, O., Bergmann, P., Brandi, M. L., Cooper, C., Devogelaer, J. P., Gielen, E., Goemaere, S., Kaufman, J. M., Rizzoli, R., and Reginster, J. Y. (2016). Effects of Dairy Products Consumption on Health: Benefits and Beliefs—A Commentary from the Belgian Bone Club and the European Society for Clinical and Economic Aspects of Osteoporosis, Osteoarthritis and Musculoskeletal Diseases. Calcif Tissue Int., 98, 1–17. doi 10.1007/s00223-015-0062-x.
- U.S. National Library of Medicine. (2020). Lactose Intolerance. Retrieved from https://ghr.nlm.nih.gov/condition/lactose-intolerance#statistics.