Is Dairy Healthy? What Science Really Says.

If you want to know the truth about dairy, and whether or not it is healthy, then you want to read this article.

Milk — it does a body good.

No doubt you heard this statement said countless times across your lifespan. Whether it be splattered across billboards or as the tagline of the iconic television commercials popular in the 1980s, milk has always been and remains to be a staple food in the diet of many people as they grow.

As children, we are told that we need milk to have strong, healthy bones. As teenagers and young adults wanting to bulk up, we’re told to drink milk (as much as a gallon a day!) to support muscle building and recovery. As full-grown adults, many of us trade in our daily glass of milk for a delicious whey protein shake. And, those of us that still enjoy milk mix our protein powder into our glass of milk for the ultimate creamy, delicious, protein-packed treat.

Young or old, there is no denying that there is something special (possibly even irreplaceable) about a cold glass of milk (along with cookies for dunking).

These days (and for quite a few years, to be honest) milk is under constant attack. Some say milk is unnatural to drink as we are the only species to consume the milk of another. Others deride milk on the basis it’s laden with all sorts of potentially harmful chemicals, hormones, and indigestible proteins that will lay siege to your immune system, turn you into a mucusy mess, and maybe even lead you to severe disease.

So, what’s the real truth about milk? Is milk horrible for you, and more importantly, how did this childhood favorite become a persona non grata in certain circles?

That’s where we come in.

We’re here to discuss the facts about milk, specifically cow’s milk. We’ll separate myth from reality, and see what actual scientific research has to say about milk regarding health, wellness, weight loss, and muscle gain.

Before we get into the common reasons people give to avoid milk, let’s briefly discuss what is actually in milk.

What Is in Milk?

Milk is a fascinatingly complex food/beverage teeming with all sorts of compounds. After all, the primary purpose of milk (regardless of the species) is to provide a source of complete nutrition for a growing infant mammal. By definition, it must contain a host of essential and beneficial nutrient to support, sustain, and enhance life and development.

Speaking regarding percentages, milk is [1,2]:

  • 87% water
  • 9% carbohydrate (lactose)
  • 4% fat
  • 3% protein
  • 7% vitamins & minerals

Breaking these categories down a bit further, we see:

  • Protein — in the form of casein and whey proteins
  • Carbohydrates — lactose, which our bodies will digest into glucose and galactose
  • Fat — composed of ~400 individual fatty acids, though only 15-20 fatty acids make up 90% of the milk fat. Regarding saturated vs. unsaturated fat, milk is 65% saturated, 30% monounsaturated, and 5% polyunsaturated fatty acids.
  • Vitamins — milk contains both water-soluble Vitamins (B family and C) along with fat-soluble Vitamins (A, D, E, & K)
  • Minerals — Calcium, Magnesium, Phosphorus, Potassium, Selenium, Iodine, and Zinc

Now that we’ve got a bit more understanding of what’s in your typical glass of moo juice let’s look at the common complaints against the consumption of milk.

Top Reasons Given to Not Drink Milk

 

Humans Are the Only Species That Drink The Milk of Another Species

This is one of the major arguments used by the anti-dairy/anti-milk pundits, and it’s also one of the weakest.

First of all, nearly every diet out there except for vegan and vegetarian promotes the consumption of meat due to its high protein content and supply of essential amino acids that our bodies need to synthesize protein and build muscle.

If it’s ok for us to eat one part of an animal (its flesh), why is it not ok to eat another food from the same animal? After all, the milk from the cow is what provided the sustenance for it to grow its muscles which we then turn into steaks and hamburgers.

Already you can see the holes in this ship, but there’s more.

Despite what the “gurus” tell you, we are not the only species to consume the milk of another species. Research shows that western gulls and feral cats drink (steal) milk from northern elephant seals. [3]

One myth busted, let’s keep moving.

Drinking Milk Leaches Calcium from Your Bones and Causes Osteoporosis

Ever since childhood, we are told that it’s important to drink milk to grow strong, healthy bones. This, of course, is because milk is particularly rich in calcium.

Recently though, there have been claims sprouting up that drinking milk causes weak bones due to the removal of calcium from them.

The critical piece of evidence commonly cited by anti-dairy pundits is an analysis of 37 studies (which was funded by a pro-vegan organization, FYI) [4] asserted that dairy consumption was not associated with bone health.

It doesn’t take a Ph.D. in nutritional sciences to see there’s an apparent conflict of interest at play here with the study, but aside from that when approaching anything from a scientific frame of mind, you consider ALL of the evidence.

You do NOT cherry-pick studies only that align with your point of view. That’s not how scientists and individuals who claim to be “evidence-based” operate.

Another reason commonly pointed to in support of the “drinking milk weakens bones” myth is that since milk is high in protein when it is digested, it will increase the acidity of your blood.

To prevent your blood from becoming too acidic, your body draws calcium from your bones into your blood to neutralize the acid

If this sounds familiar, it’s because this idea lies at the core of the acid-alkaline diet, which promotes the concept that you should choose foods that exert an alkalizing effect in the body and avoid acid-forming foods.

However, there’s next to no legitimate scientific evidence to back this theory. Additionally, blood pH is not influenced by one’s diet (which means you can stop wasting money on those overpriced alkaline water systems, too.) If it was, you could eat the wrong foods at the wrong time and wind up dead.

Fortunately, the body maintains tight control over blood pH, much like it does core temperature. This is one of the primary functions of the stomach. It mixes the food you eat with all sorts of acids and other agents that make the food safe to continue transit through your body and for it to ultimately be absorbed.

Additionally, just because urine pH is acidic doesn’t inherently mean your body is in a state of ill health or metabolic acidosis. [5]

Furthermore, when you consider all of the evidence, the research is pretty clear in that dairy is bone-protective. [9,10] And, there’s also some other research showing that eating more protein also improves bone health. [6,7,8]

Now, this doesn’t mean you have to consume dairy or drink milk to have healthy bones, as there are many other familiar food sources the provide calcium. It’s just easier to hit your calcium and vitamin D goals if you do consume dairy.

What is Vitamin D essential concerning calcium?

Vitamin D is a fat-soluble vitamin that our bodies can synthesize when exposed to direct sunlight. However, due to longer commutes, more time spent indoors working or playing, and living in areas that don’t receive a significant amount of sunshine for considerable portions of the year has led to a bit of an epidemic of vitamin D deficiency.

Why is this important?

Vitamin D is needed to synthesize many hormones in the body, including testosterone. And, it’s also required for your body to absorb calcium properly.

This is commonly why dairy has vitamin D3 added to it.

Now, let’s move onto the next reason the anti-dairy crowd give as proof of why you should avoid milk and dairy.

Milk is Laced with Hormones

Cows are typically injected with hormones to increase their growth and rate of milk production. Included in the hormones given to these cows is recombinant bovine growth hormone (rBGH) and bovine somatotropin (bST).

Cows that are given these injections increase the concentration of insulin-like growth factor-1 (IGF-1) in the cow’s milk. This has alarmed some people due to the fact that there is some research noting a link between IGF-1 and cancer.

And, as you’ve probably heard, these hormones are carried over into the milk sitting on your store shelf. It’s not as scary sounding as you might think.

First, the amount of these hormones that make it into the milk are meager. [11] This is because the majority of the hormones present in the milk directly after milking are destroyed during the pasteurization process. [12]

Furthermore, unlike other steroid hormones, which can be taken orally, IGF-1 and rBGH must be injected to exert any effects in the body. When consumed orally, IGF-1 and rBGH are destroyed during digestion.

In other words, drinking milk from cows injected with hormones doesn’t mean you are absorbing the hormones. Your body destroys them. So, unless you are injecting milk, you have nothing to worry about.

Regarding the IGF-1 — cancer link and milk consumption, it is true that drinking milk increases the body’s production of IGF-1. [13]

 But, that does not automatically translate to “drinking milk causes cancer because it raises IGF-1.”

IGF-1 is needed for cell growth and regeneration, which makes it a marker for assessing the progression of cancer as at its core, cancer is the uncontrolled multiplying of malignant cells.

However, there has yet to be any concrete proof that IGF-1 directly “causes” cancer. The peptide hormone is associated with various cancers but has not been found to be causative. [14]

Furthermore, a 2016 review of dairy studies and meta-analyses concluded that:

“Consumption of milk and dairy products probably protects against colorectal cancer, bladder cancer, gastric cancer, and breast cancer. Dairy intake does not seem to be associated with risk of pancreatic cancer, ovarian cancer, or lung cancer, whereas the evidence for prostate cancer risk is inconsistent. In women, dairy offers significant and robust health benefits in reducing the risk of the common and serious colorectal cancer and, possibly, also the risk of breast cancer. In men, the benefit of the protective effect of milk and dairy on the common and serious colorectal cancer is judged to outweigh a potentially increased risk of prostate cancer.”[15]

Suffice it to say another myth about drinking milk has been busted.

Milk and Chronic Disease

Media outlets (including social media) love to cause a frenzy in the hopes of attracting viewers. Given the controversy over dairy in recent years, it’s become relatively common to see news outlets and various other organizations make some outlandish claims about dairy, specifically that it increases the risk of several chronic diseases including:

  • Type 2 Diabetes
  • Obesity
  • Cardiovascular Disease
  • Cancer
  • All-cause Mortality

When you get past the scare tactics, sensationalism, and fear-mongering, and read the published scientific literature, you see that dairy does NOT adversely impact health. It may benefit one’s health and resistance to chronic disease.

Multiple reviews have demonstrated that not only is milk not detrimental to your health it does do a body good.

Consider the conclusion from this 2016 review on dairy which stated:

“The totality of available scientific evidence supports that intake of milk and dairy products contribute to meet nutrient recommendations, and may protect against the most prevalent chronic diseases, whereas very few adverse effects have been reported.” [15]

In that same review, researchers also noted that consumption of dairy and milk was shown to improve body composition and support weight loss during periods of dieting.

Milk and dairy consumption was also associated with a reduced risk of type 2 diabetes, stroke, and cardiovascular disease: And the evidence also indicates milk has a beneficial effect on bone mineral density.

There’s more though.

A recent 2018 study published in The Lancet followed 136,000 people across 21 countries for roughly nine years. Researchers had subjects complete surveys notating their dairy intake. Those who consumed a higher amount of dairy exhibited lower risks of cardiovascular disease and stroke than those who consumed little to no dairy.

Furthermore, these associations held no matter if subjects consumed mostly low-fat or whole-fat dairy products. [16]

Again, this is epidemiological data, so it’s not concrete proof makes you healthy, but dairy consumption sure does not have a negative impact on one’s health.

Milk Causes Fat Gain

Milk has been recommended as a staple food for bulking up for decades. And plenty of people have put on a lot of weight (fat) while drinking milk (GOMAD diet anyone?).

And, if you’re struggling to gain weight, consuming some extra liquid calories can help you put on weight easier as liquid calories don’t pack the same satiety punch as whole foods.

However, this doesn’t mean inherently that milk causes weight gain, just like sugar, bananas, pasta, or any other single food doesn’t directly cause fat gain.

Consuming too many calories does.

Remember, weight gain is about calories in vs. calories out.

If you consume a diet consisting solely of the cleanest, gluten-free, sustainably sourced, organic food possible and avoided milk and dairy entirely, yet you still consume more total calories than you burn in a day, you will gain weight.

It’s as simple as that.

Milk (or any other food) does not directly lead to fat gain.

Many studies have shown that not only does milk NOT lead to weight gain, but it may also actually enhance fat loss and muscle gain. [17,18]

Additional research comparing calcium intake from dairy vs. pure calcium supplements notes that those who get their calcium from dairy experience significantly greater fat loss than those getting their calcium from supplements. [20,21]

Researchers believe that dairy contains several other beneficial bio-active compounds the promote extra fat burning which is not found in calcium supplements.

In regards to supporting muscle growth, dairy products contain whey and casein protein, both of which have been shown in research trials to enhance the anabolic effects of resistance training and support increases in lean muscle mass. [22,23,24]

Should I Drink Milk and Consume Dairy?

This ultimately is up to you.

Many people have trouble digesting dairy due to the lactose present in milk. The lactase enzyme is needed, and a significant portion of the population stops producing this enzyme between the ages of 2 and 3.

Now, this doesn’t mean you have to stop consuming dairy altogether. They do make low/no-lactose dairy products, including various kinds of milk that have added lactase enzymes or the lactose has been completely removed.

Another option is to consume a separate lactase enzyme or source any of the dairy-alternative milk on the market.

A final option is to consume whey protein powder, such as SteelFit® Steel Whey. High-quality whey protein powders remove nearly all of the lactose present in milk during the filtration process. But it still retains many of the beneficial immune-boosting fractions naturally present in whey protein and milk.

The choice to consume milk (and to a greater extent dairy) is up to you. Provided that you can tolerate dairy, there’s no reason to avoid it aside from personal preference.

It does not leach calcium from your bones, won’t infect you with cow hormones, and it won’t increase your risk of all sorts of chronic diseases.

Milk may, however, help you lose weight and build muscle as well as help you to meet your micronutrient goals for the day as well.

References

  1. Dairy extension. (n.d.). Composition of Milk Key Terms. Cornell Education, 1–5. Retrieved from https://dairyextension.foodscience.cornell.edu/sites/dairyextension.foodscience.cornell.edu/files/shared/Composition of Milk.pdf
  2. “Milk Composition | MilkFacts.info.” Home | MilkFacts.info, www.milkfacts.info/Milk%20Composition/Milk%20Composition%20Page.htm.
  3. Gallo-Reynoso JP, Ortiz CL. Feral cats steal milk from northern elephant seals. THEYRA. 2010 Dec;1(3):207-12.
  4. Lanou AJ , et al. “Calcium, Dairy Products, and Bone Health in Children and Young Adults: a Reevaluation of the Evidence. – PubMed – NCBI.” National Center for Biotechnology Information.
  5. Fenton, T. R., & Lyon, A. W. (2011). Milk and Acid-Base Balance: Proposed Hypothesis versus Scientific Evidence. Journal of the American College of Nutrition, 30(sup5), 471S-475S. doi:10.1080/07315724.2011.10719992
  6. Shams-White MM , et al. (n.d.). Dietary protein and bone health: a systematic review and meta-analysis from the National Osteoporosis Foundation. – PubMed – NCBI.
  7. Kerstetter JE , et al. (n.d.). Dietary protein and skeletal health: a review of recent human research. – PubMed – NCBI.
  8. JP, B. (n.d.). Dietary protein: an essential nutrient for bone health. – PubMed – NCBI. Retrieved from https://www.ncbi.nlm.nih.gov/pubmed/16373952
  9. RP, H. (n.d.). Dairy and bone health. – PubMed – NCBI.
  10. Caroli, A., et al. “Invited review: Dairy intake and bone health: A viewpoint from the state of the art.” Journal of Dairy Science, vol. 94, no. 11, 2011, pp. 5249-5262.
  11. Collier, R. J., and D. E. Bauman. “Update on human health concerns of recombinant bovine somatotropin use in dairy cows.” Journal of Animal Science, vol. 92, no. 4, 2014, pp. 1800-1807.
  12. Groenewegen, Paul P., et al. “Bioactivity of Milk from bST-Treated Cows.” The Journal of Nutrition, vol. 120, no. 5, 1990, pp. 514-520.
  13. Qin, Li-Qiang, et al. “Milk consumption and circulating insulin-like growth factor-I level: a systematic literature review.” International Journal of Food Sciences and Nutrition, vol. 60, no. sup7, 2009, pp. 330-340.
  14. Meinbach, David S., and Bal L. Lokeshwar. “Insulin-like growth factors and their binding proteins in prostate cancer: Cause or consequence?.” Urologic Oncology: Seminars and Original Investigations, vol. 24, no. 4, 2006, pp. 294-306.
  15. Thorning TK, Raben A, Tholstrup T, Soedamah-Muthu SS, Givens I, Astrup A. Milk and dairy products: good or bad for human health? An assessment of the totality of scientific evidence. Food Nutr Res. 2016;60:32527. Published 2016 Nov 22. doi:10.3402/fnr.v60.32527
  16. Dehghan, M., Mente, A., Rangarajan, S., Sheridan, P., Mohan, V., Iqbal, R., Yusuf, S. (2018). Association of dairy intake with cardiovascular disease and mortality in 21 countries from five continents (PURE): a prospective cohort study. The Lancet, 392(10161), 2288-2297. doi:10.1016/s0140-6736(18)31812-9
  17. Stonehouse W, Wycherley T, Luscombe-Marsh N, Taylor P, Brinkworth G, Riley M. Dairy Intake Enhances Body Weight and Composition Changes during Energy Restriction in 18-50-Year-Old Adults-A Meta-Analysis of Randomized Controlled Trials. Nutrients. 2016;8(7):394. Published 2016 Jul 1. doi:10.3390/nu8070394
  18. Chen M, Pan A, Malik VS, Hu FB. Effects of dairy intake on body weight and fat: a meta-analysis of randomized controlled trials. Am J Clin Nutr. 2012;96(4):735-47.
  19. Lu, L., et al. “Long-term association between dairy consumption and risk of childhood obesity: a systematic review and meta-analysis of prospective cohort studies.” European Journal of Clinical Nutrition, vol. 70, no. 4, 2016, pp. 414-423.
  20. Zemel MB: Role of dietary calcium and dairy products in modulating adiposity. Lipids 38:139–146, 2003
  21. Shahar, D. R., et al. “Does Dairy Calcium Intake Enhance Weight Loss Among Overweight Diabetic Patients?” Diabetes Care, vol. 30, no. 3, 2007, pp. 485-489.
  22. Joy JM, Vogel RM, Shane Broughton K, et al. Daytime and nighttime casein supplements similarly increase muscle size and strength in response to resistance training earlier in the day: a preliminary investigation. J Int Soc Sports Nutr. 2018;15(1):24. Published 2018 May 15. doi:10.1186/s12970-018-0228-9
  23. Wilborn CD, Taylor LW, Outlaw J, et al. The Effects of Pre- and Post-Exercise Whey vs. Casein Protein Consumption on Body Composition and Performance Measures in Collegiate Female Athletes. J Sports Sci Med. 2013;12(1):74-9. Published 2013 Mar 1.
  24. Volek, Jeff S., et al. “Whey Protein Supplementation During Resistance Training Augments Lean Body Mass.” Journal of the American College of Nutrition, vol. 32, no. 2, 2013, pp. 122-135.

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