Dairy foods are commonly recommended to children, but should adults consume dairy? The short answer is yes. So let’s take a look as to why adults between the ages of 19-59 should be incorporating dairy into their everyday diet. 

Dairy for decreased disease risk 

As of 2020, 41.9% of the United States (U.S.) population is considered to have obesity, 7.2% of the population has coronary artery disease (CAD), and as of 2019, 11.3% of the population has diabetes.1-3 These staggering statistics do not include the amount of people who are at risk for heart disease or pre-diabetes as well. To help combat the high prevalence of obesity and other chronic diseases, dietary changes are strongly recommended. Incorporating low-fat or fat-free dairy foods into the diet has been associated with reduced risk of many chronic diseases, such as cardiovascular disease and type 2 diabetes.4,5 

Chronic disease can also be a cause of inflammation, and contrary to popular belief, recent research has shown that dairy does not contribute to an increase in inflammation, but may even reduce chronic inflammation.4,5 Additionally, fortified dairy products may improve cardiometabolic risk biomarkers.5 Lastly, dairy provides essential nutrients such as vitamins A and D, zinc, and selenium, which all play an important role in the immune system to help fight off infections.4 

Dairy for weight loss

With the prevalence of obesity exceeding over 40% of the U.S. population, weight loss is recommended for many adults.1 However, losing weight can be extremely challenging. Incorporating dairy into a well-balanced diet may help weight loss goals. Current evidence shows that dairy consumption can increase lean body mass and reduce body fat.6

The high protein content in dairy helps contribute to its benefit on weight management. When losing weight, it is important to be in an overall calorie deficit. Dairy’s high-quality protein helps prevent the loss of muscle mass during this period of weight loss.6 In addition, protein at meals helps promote satiety and can prevent overeating. Simple carbohydrates digest quickly when eaten alone, and hunger can recur quickly thus promoting overeating. Adding a protein source meals can help slow digestion and help individuals feel fuller for a longer period of time.7 For example, it would be more beneficial to pair cereal in the morning with Greek yogurt or cow’s milk due to their high protein content rather than consuming cereal alone or with a low-protein beverage, such as almond milk. 

Research is also showing that dairy foods that contain probiotics, such as yogurt or kefir, can actually reduce weight gain.6 A recent systematic review and meta-analysis of 15 randomized controlled trials showed that individuals who consumed probiotic foods had a significantly reduced bodyweight, BMI, and fat percentage compared with the placebo.8 It was also found that probiotics had an improvement on blood glucose, insulin, and insulin resistance, which may be beneficial for those who have type two diabetes as well.9

Dairy for bone health

The adult lifespan spreads over the course of 40 years. During these years the body undergoes many physical changes. In the earlier stages of adulthood, dairy foods provide calcium, vitamin D, and protein, which are important for accruing peak bone mass around the ages of 25-30.4,10,11   Diet can impact our peak bone mass either positively or negatively. A consistently poor diet that is not rich in essential vitamins and minerals can negatively affect bone mass, whereas a high-quality diet that is rich in bone-supporting nutrients can greatly improve bone mass.10 Dairy foods uniquely offer nutrients that are essential for bone growth like calcium, vitamin D, phosphorus, potassium and magnesium.11 As an added bonus, the vitamin D in fortified dairy foods helps our bodies better absorb its calcium. 

Current research shows that consuming dairy can help maintain bone mass throughout adulthood and is associated with reduced fracture risk and greater bone mineral density.11 As we age, the risk of osteoporosis and bone fractures increases, especially in women.11 By the age of 40, the loss of bone mass begins to occur, which can lead to osteoporosis over time. To help prevent this, regular exercise and a diet rich in calcium and vitamin D can help slow the rate of bone mass loss.10,11 A recent meta-analysis found that the consumption of dairy increased bone mineral density in women and concluded that dairy intake is an effective way to help prevent osteoporosis in postmenopausal women.12 

A decline in bone mineral density is also a concern with weight loss, especially in the female population.11 To help prevent any further decrease of bone mineral density, prioritizing dairy foods that are high in both protein and calcium can aid with weight loss while ensuring that bone mineral density does not decline further.6,11 In a recent clinical trial, postmenopausal women participated in a weight loss study while consuming 4-5 servings of low-fat dairy foods per day or calcium and vitamin D supplements. The participants that consumed dairy foods had better bone health outcomes than those in the control group.13 Evidence also supports that higher intakes of milk, yogurt, and cheese are linked to greater bone mineral density in men as well.14

Dairy for muscle mass maintenance

Similar to bone mass, muscle mass can also begin to decline as early as 40-50 years old.15 Sarcopenia is the term that describes the loss of muscle mass and strength, and like osteoporosis, it can become heightened with poor diet and lack of regular physical activity. A diet low in protein has been associated with decreased muscle mass.15 Sufficient dietary protein helps enhance muscle building activity and provides essential amino acids to promote muscle protein synthesis.15

Dairy is a high-quality protein source that contains all essential amino acids which helps with the prevention of muscle mass loss and can promote muscle protein synthesis.15 Leucine is an important amino acid that is needed for muscle protein synthesis. Dairy foods, particularly milk, contain whey protein, which is a naturally good source of this essential amino acid.15 In addition, dairy foods can be very affordable and many do not require cooking, which makes it a practical option for adults of all ages with a busy schedule. 

Incorporating Dairy

Dairy contains many essential vitamins and minerals, such as vitamins A and B12, riboflavin, niacin, phosphorus, and zinc. Because dairy foods are so uniquely nutrient dense, they are beneficial to incorporate into the diet to help prevent any nutrient deficiencies and support our health in many ways. From immune health to bone and muscle mass retention, to weight management and disease prevention, dairy foods have a lot to offer. These benefits can be achieved by getting in the recommended intake of 3 servings of dairy products per day.4,16 For most dairy products that are liquids or yogurts, one serving of dairy is equal to one cup. For cheeses, serving sizes are generally 1-1.5 ounces, and for cottage cheese, a serving is two cups. Incorporating dairy into the diet doesn’t have to be done by just drinking milk. To optimize nutrient diversity, try incorporating dairy intake with plant foods, such as berries and Greek yogurt, cottage cheese and peaches, or feta baked with tomatoes.  

Contrary to the many nutritional myths surrounding dairy, dairy foods can play an important role in the health of adults. Daily dairy intake can help reduce the risk of nutritional deficiencies and chronic disease, prevent the loss of bone mineral density and muscle mass, promote the development of muscle mass, and aid with weight management. Dairy can be incorporated into the diet by drinking or cooking with milk, having Greek yogurt or cottage cheese at breakfast, adding whey protein powder to smoothies, or adding fresh mozzarella to sandwiches. There are so many delicious and affordable ways to make dairy an easy addition to the everyday diet. 

References: 

1. https://www.cdc.gov/obesity/data/adult.html
2. https://www.cdc.gov/heartdisease/facts.htm
3. https://diabetes.org/about-us/statistics/about-diabetes 
4. https://www.usdairy.com/getmedia/618a5611-a8ff-4c5d-9161-bd2e48a5b0d3/NDC_Lifespan_Adults_FINAL-12-01-2021.pdf?ext=.pdf
5. Gil Á, Ortega RM. Introduction and Executive Summary of the Supplement, Role of Milk and Dairy Products in Health and Prevention of Noncommunicable Chronic Diseases: A Series of Systematic Reviews. Adv Nutr. 2019 May 1;10(suppl_2):S67-S73. doi: 10.1093/advances/nmz020. PMID: 31089742; PMCID: PMC6518123.
6. Dariush Mozaffarian, Dairy Foods, Obesity, and Metabolic Health: The Role of the Food Matrix Compared with Single Nutrients, Advances in Nutrition, Volume 10, Issue 5, September 2019, Pages 917S–923S, https://doi.org/10.1093/advances/nmz053
7. Wilde PJ. Eating for life: designing foods for appetite control. J Diabetes Sci Technol. 2009 Mar 1;3(2):366-70. doi: 10.1177/193229680900300219. PMID: 20144369; PMCID: PMC2771510.
8. Borgeraas, H.,  Johnson, L. K.,  Skattebu, J.,  Hertel, J. K., and  Hjelmesæth, J. (2018)  Effects of probiotics on body weight, body mass index, fat mass and fat percentage in subjects with overweight or obesity: a systematic review and meta-analysis of randomized controlled trials. Obesity Reviews,  19:  219– 232. doi: 10.1111/obr.12626.
9. Ruan Y, Sun J, He J, Chen F, Chen R, Chen H. Effect of Probiotics on Glycemic Control: A Systematic Review and Meta-Analysis of Randomized, Controlled Trials. PLoS One. 2015 Jul 10;10(7):e0132121. doi: 10.1371/journal.pone.0132121. PMID: 26161741; PMCID: PMC4498615.
10. https://orthoinfo.aaos.org/en/staying-healthy/healthy-bones-at-every-age/
11. https://www.usdairy.com/getmedia/1db50585-9c11-4c40-acf6-a132ee3802b7/Science-Summary-Bone-Health-2021.pdf?ext=.pdf
12. Shi Y, Zhan Y, Chen Y, Jiang Y. Effects of dairy products on bone mineral density in healthy postmenopausal women: a systematic review and metaanalysis of randomized controlled trials. Arch Osteoporos. 2020;15(1):1-8. doi:10.1007/s11657-020-0694-y
13. Ilich JZ, Kelly OJ, Liu PY, et al. Role of calcium and low-fat dairy foods in weight-loss outcomes revisited: Results from the randomized trial of effects on bone and body composition in overweight/obese postmenopausal women. Nutrients. 2019;11(5). doi:10.3390/nu11051157
14. van Dongen LH, Kiel DP, Soedamah-Muthu SS, Bouxsein ML, Hannan MT, Sahni S. Higher Dairy Food Intake Is Associated With Higher Spine Quantitative Computed Tomography (QCT) Bone Measures in the Framingham Study for Men But Not Women. J Bone Miner Res. March 2018. doi:10.1002/jbmr.3414
15. Hanach NI, McCullough F, Avery A. The Impact of Dairy Protein Intake on Muscle Mass, Muscle Strength, and Physical Performance in Middle-Aged to Older Adults with or without Existing Sarcopenia: A Systematic Review and Meta-Analysis. Adv Nutr. 2019 Jan 1;10(1):59-69. doi: 10.1093/advances/nmy065. PMID: 30624580; PMCID: PMC6370271.
16. U.S. Department of Agriculture and U.S. Department of Health and Human Services. Dietary Guidelines for Americans, 2020-2025. 9th Edition. December 2020.