The Truth About Dairy

Lately, dairy’s popularity has taken a hit. With increased recognition of vegan and plant-based diets, many people assume that dairy has a negative affect on health. Although plant-based diets are great, it’s extremely important that we do the proper research before cutting certain foods out of our diet completely, dairy included. However, with the amount of accurate information out there, there is just as much, if not more, inaccurate information to counter it. That being said, it’s essential to make sure you’re getting your information from reliable sources. Obviously the goal of this blog to provide “clarity in a world of confusing diet advice,” so I wanted to do a sort of meta-analysis in today’s post, in order to clear up some misconceptions. Within the post, there are links to sites and research studies that back up what I’m saying (so you don’t just have to take my word for it). I also have a complete list of my sources at the end in case you wanted to see them that way as well.

Nutrient Content

Milk is one of those foods that seems to have a little bit of everything. It contains all three macronutrients (carbohydrates, fat, and protein), as well as many essential micronutrients. One cup of 2% milk contains the following:

• 8 g protein
• 12 g carbohydrates
• 5 g fat
• 342 mg potassium (9% DV)
• 464 IU vitamin A (11% DV)
• 1.3 ug vitamin B12 (22% DV)
• 120 IU vitamin D (30% DV)
• 293 mg calcium (29% DV)
• 224 mg phosphorus (22% DV)
• 0.45 mg riboflavin (26% DV)

Bone Health

Calcium and phosphorus are some of the most important nutrients when it comes to bone health. And dairy products are one of the easiest ways to get them into your diet, because of their bioavailability. When the body is given the proper amount of calcium, it is able to store enough of it in the bones to make them solid and strong. Whereas, if we are calcium deficient we are at a greater risk for having porous bones, and therefore diseases such as osteoporosis. In dairy products, phosphorus forms a micelle with calcium, making the calcium more soluble and bioavailable than it would be on its own. (Basically you are able to absorb more calcium.) Vitamin D (which is usually added to milk through fortification), along with magnesium, zinc, and potassium also play a role in bone health because they aid in the process of calcium absorption.

Recently, there has been some controversy as to whether milk actually helps with bone health at all. One recent study done in Sweden suggests that a higher intake of dairy might actually increase risk of fracture in women, though not in men. However, the authors of the study strongly caution readers that much more research is needed to actually prove a correlation, due to the fact that it was simply an observational study, and other factors (such as physical activity, other aspects of diet, and disease history) were not considered. Also, for this one study that has been done, there are countless other studies that show the exact opposite. So although many anti-dairy folks are taking this study and running with it, maybe a little bit more research should be done before jumping to conclusions.

Some medical professionals also claim that milk may not improve calcium intake, due to the fact that calcium is needed to transport animal protein (which is obviously also present in milk). So does this mean that the calcium present in milk is simply being cancelled out due to the presence of animal protein? Well, not necessarily. Other medical professionals say that this isn’t really an issue. Why? Because the amount of calcium in milk versus the amount needed for protein transport is very different. Apparently for every glass of milk (which has 8 grams of protein), the body only uses 14 of the 300 mg of calcium to transport protein. So you are still getting 286 mg of calcium per glass. Which still makes milk one of the best sources of calcium out there.

Obesity & Diabetes

Milk has also been shown to have a significant impact on obesity and diabetes risk. Study after study after study after study (and probably many more) has shown an inverse relationship between dairy intake and conditions like obesity, diabetes, and metabolic syndrome. Some of these studies were done with low-fat dairy, but some were done with high-fat dairy. So though there is a perceived health risk commonly associated with high-fat dairy, maybe it’s not so bad after all.

Cancer

Milk’s influence on cancer, like with most other things, is a little bit confusing. In other words, the results are a little bit mixed. For example, dairy has shown to potentially decrease risk of colorectal cancer. Yet, it has also been shown to potentially increase risk of prostate cancer. With other cancers, such as breast and gastric cancers, dairy intake appears to have no affect.

The Microbiota

Pre- and probiotics have really blown up in the past few years. Gut health is now more talked about than ever. Probiotics specifically are known for populating the live cultures inside the GI tract, and in turn, promoting immunity and overall health. So what is dairy’s role in this hot topic? Well many dairy products are fermented, such as cheeses, yogurts, kefir, and sour cream. These fermented products are a good source of probiotics, and therefore are really beneficial for GI health. Also, to the right is a diagram (that I found here) that shows some other benefits of fermented dairy.

Cognitive Health

Dairy has also been shown to positively impact brain health. Milk contains something called a milk fat globule membrane (MFGM), defined has “an oil droplet enclosed in plasma membrane from the lactating cell.”  MFGMs have been attributed to many cognitive benefits, including its impact on Alzheimer’s onset, memory, depression, and stress.

Another study indicated that “dairy intake is associated with brain glutathione concentration in older adults.” Glutathione acts as an antioxidant. Specifically, cerebral glutathione is an antioxidant present in the brain. Because of how much oxygen is used up by the brain, there are many reactive oxygen species constantly being generated. This is why cerebral glutathione is so important. This study found that those who had a higher dairy intake also had higher concentrations of cerebral glutathione. Based on these results, dairy may help produce antioxidants in the brain.

Heart Health

Last but not least, I want to cover dairy’s impact on heart health. MFGMs (which I mentioned above) not only affect the brain, they also affect blood pressure. MFGMs, ACE-inhibitors, milk peptides, and various other nutrients present in dairy products have been shown to have anti-hypertensive affects. They lower blood pressure and therefore reduce risk of heart disease and stroke. As shown in the image above, fermented dairy products also alter cholesterol levels, raising HDL (good) cholesterol and lowering LDL (bad) cholesterol.

Is There Anyone Who Shouldn’t Consume Dairy?

Obviously if you are diagnosed with lactose intolerance, you experience horrible discomfort and GI symptoms from consuming dairy. So it’s probably a good idea to stay away from it. But if you do not have lactose intolerance, there’s really no reason to avoid dairy products.

Conclusion

Ok, so that was a lot of information. I hope you were able to learn a few things about dairy and now feel that you have a more well-rounded understanding of the health implications. It’s important to always be vigilant while grocery shopping. Just because dairy itself is good for you doesn’t mean that those heavily processed “cheese” balls are. Recommended servings per day and fat content are also things to pay attention to. Given all the health benefits and versatility, I personally love dairy products. While I also enjoy almond and soy milk, I definitely consume a good amount of dairy milk as well. And yogurt is a huge staple in my diet. Whether or not you consume dairy products is completely up to you. But I think it’s important to be informed before you decide either way.

Sources

While I always link my sources within my posts, I wanted to make it extremely clear that this information is not simply my opinion. It is backed by many research studies and other professional opinions. Here is a comprehensive list of my sources for this post, in case you wanted to check them out for yourself.

1. https://www.ncbi.nlm.nih.gov/pubmed/29494487
2. https://onlinelibrary.wiley.com/doi/epdf/10.1111/1541-4337.12183
3. https://link.springer.com/article/10.1007%2Fs00394-012-0418-1
4. https://www.heart.org/en/healthy-living/healthy-eating/eat-smart/nutrition-basics/suggested-servings-from-each-food-group
5. https://www.ncbi.nlm.nih.gov/pubmed/21173413
6. https://www.eatright.org/food/vitamins-and-supplements/types-of-vitamins-and-nutrients/calcium
7. https://www.choosemyplate.gov/dairy-nutrients-health
8. https://www.ncbi.nlm.nih.gov/pubmed/16801582
9. https://www.ncbi.nlm.nih.gov/pubmed/21753066
10. https://www.nature.com/articles/1601869
11. https://www.cancer.gov/about-cancer/causes-prevention/risk/diet/calcium-fact-sheet#r27
12. https://academic.oup.com/ajcn/article/101/2/287/4494384
13. https://www.ncbi.nlm.nih.gov/pubmed/21617020
14. https://www.healthyeating.org/Milk-Dairy/Nutrients-in-Milk-Cheese-Yogurt/Nutrients-in-Milk
15. https://ods.od.nih.gov/factsheets/VitaminD-HealthProfessional/
16. https://www.hsph.harvard.edu/nutritionsource/what-should-you-eat/calcium-and-milk/calcium-full-story/#calcium-from-milk
17. https://www.bmj.com/content/349/bmj.g6015
18. https://www.webmd.com/food-recipes/features/milk-for-your-bones#1
19. https://www.ncbi.nlm.nih.gov/pubmed/16333032
20. https://www.eatright.org/food/vitamins-and-supplements/nutrient-rich-foods/prebiotics-and-probiotics-creating-a-healthier-you
21. https://www.mayoclinic.org/what-are-probiotics/art-20232589
22. https://www.ncbi.nlm.nih.gov/pubmed/15956291?dopt=Abstract
23. https://www.sciencedirect.com/science/article/abs/pii/0304415775900118
24. https://pubchem.ncbi.nlm.nih.gov/compound/glutathione#section=Top
25. https://www.ncbi.nlm.nih.gov/pubmed/1088085
26. https://academic.oup.com/jn/article/137/3/825S/4664770