Dairy and human health: Is it really so bad?

In recent years, there has been a notable decline in the popularity of dairy products, driven by various factors including health concerns. While animal dairy products, including milk, cheese, and yogurt, are renowned for their rich nutritional profile, boasting essential nutrients such as calcium, vitamin D, protein, and various micronutrients, changing perceptions about health and nutrition have led many consumers to reconsider the role of dairy in their diets. Concerns regarding the potential adverse effects of certain components found in dairy on human health are continuously arising, and with conflicting findings and evolving perspectives, we were interested in revisiting the latest scientific evidence to understand better the impact of dairy products on human health.

Cardiovascular health:

Numerous studies have explored the link between dairy consumption and cardiovascular health. In particular, the saturated fat content in dairy is the subject of debate with some advocating for reduced intake of high-fat dairy to manage cholesterol levels and mitigate CVD risk factors. Clinical evidence strongly supports the idea that dairy consumption does not increase the risk of CVD (Chiu et al., 2016; Mishali et al., 2019) or adversely affect cholesterol levels, triglycerides, free fatty acids, or blood pressure (Schmidt et al., 2021). In fact, a study by Chiu et al. (2016) revealed that incorporating whole-milk dairy improved participants' triglyceride levels. However, it should be noted that some of these studies have faced criticism for relying on an observational study design, where dairy intake is self-reported; potentially introducing recall bias and under-reporting.

The vast majority of published studies indicate that dairy consumption does not increase cardiovascular risk.

Metabolic disorders:

Observational studies have consistently indicated that dairy consumption does not significantly impact glucose control in individuals with diabetes (Mitri et al., 2020; Schmidt et al., 2021). Moreover, research suggests a lower incidence of type 2 diabetes and metabolic dysfunction among individuals who consume dairy products (Choi et al., 2005). In a study by Chiu et al. (2016), the inclusion of whole-milk dairy foods was found to improve insulin sensitivity, further supporting the favourable effects of dairy consumption (Schmidt et al., 2021). Similarly, other investigations have reported that higher milk intake is associated with a reduced risk of type 2 diabetes (Tian et al., 2017), metabolic syndrome (Mena-Sánchez et al., 2019), and obesity (Wang et al., 2016). It should also be noted that producers frequently add fat and sugar to plant-based milks; potentially increasing the risk of metabolic disorders (Ratajczak et al., 2021).

The overall indication is that dairy consumption does not increase the risk of metabolic disorders.

Bone health:

One of the most widely touted benefits of dairy consumption is its positive impact on bone health, attributed to its calcium and vitamin D content. Both children and adults avoiding dairy products are at higher risk of fracture when following a diet devoid of dairy products (Rizzoli, 2022). In particular, fermented dairy products such as yoghurt or kefir, also contain bacteria, which may be especially beneficial for bone health (Aryana & Olsen, 2017). While some question the necessity of dairy for maintaining strong bones given the availability of other calcium-rich alternatives like leafy greens and fortified foods, it's important to acknowledge that milk and dairy foods are the most easily accessible sources of calcium. Moreover, many of these alternatives such as rice, oat, and almond milk have very low protein content compared to dairy (Ratajczak et al., 2021).

Overall, dairy foods are the most easily accessible sources of calcium and can contribute substantially to an individual’s daily protein intake.

Cancer:

Evidence regarding the relationship between dairy consumption and cancer risk remains inconclusive; with the current research; dominated by many study designs and of low to moderate quality. While many studies find no increased cancer risk with dairy consumption (Jeyaraman et al., 2019; Lu et al., 2016), some studies suggest that high intake of dairy products, particularly those high in saturated fats, may be associated with an increased risk of certain cancers, such as prostate and breast cancer (Lu et al., 2016; Missmer et al., 2002). However, other research indicates that dairy consumption (particularly low-fat, and fermented dairy products) could have a protective effect against certain cancers; including breast cancer (Lu et al., 2016; Jin & Je, 2022; Arafat et al., 2023). The conflicting findings may be attributed to various factors, including differences in study design and quality, population demographics, and dairy processing methods.

Overall, more high-quality research is needed to better understand the potential link between dairy consumption and cancer risk.

In summary, the relationship between animal dairy consumption and human health remains a complex and multifaceted topic, with ongoing research continuously revealing potential benefits and risks. We are also not ignorant to the other issues surrounding dairy consumption such as intolerances or allergies, and ethical and environmental concerns. Our recommendation for anyone who has eliminated any major food group from their diet is to consult a dietician or nutritionist to ensure their nutritional needs are adequately met. However, when examining the issue solely from a human health perspective, the research indicates that dairy consumption does more good than harm.

*Disclaimer*

The information presented in this article is for educational purposes only and is based on our interpretation of the current research. Individuals with specific health concerns or dietary restrictions should consult with qualified healthcare professionals or registered dietitians for personalised guidance and recommendations tailored to their individual needs and circumstances.

References:

Arafat, H. M., Omar, J., Shafii, N., Naser, I. A., Al Laham, N. A., Muhamad, R., Al-Astani, T. A. D., Shaqaliah, A. J., Shamallakh, O. M., Shamallakh, K. M., & Abusalah, M. A. H. (2023) The association between breast cancer and consumption of dairy products: A systematic review. Annals of Medicine, 55(1). Htt[://doi.org/10.1080/07853890.2023.2198256

Aryana, K. J., Olson, D. W. (2017). A 100-year review: Yogurt and other cultured dairy products. Journal of Dairy Science, 100, 9987–10013. http://doi.org/10.3168/jds.2017-12981

Bechthold, A., Boeing, H., Schwedhelm, C., Hoffmann, G., Knuppel, S., Iqbal, K., De Henauw, S., Michels, N., Devleesschauwer, B., Schlesinger, S., et al. (2019). Food groups and risk of coronary heart disease, stroke and heart failure: A systematic review and dose-response meta-analysis of prospective studies. Critical Reviews in Food Science and Nutrition, 59, 1071–1090. http://doi.org/10.1080/10408398.2017.1392288.

Chiu, S., Bergeron, N., Williams, P. T., Bray, G. A., Sutherland, B., Krauss, R. M. (2016) Comparison of the DASH (Dietary Approaches to Stop Hypertension) diet and a higher-fat DASH diet on blood pressure and lipids and lipoproteins: A randomized controlled trial. American Journal of Clinical Nutrition, 103, 341–347. http://doi.org/10.3945/ajcn.115.123281. 

Choi, H. K., Willett, W. C., Stampfer, M. J., Rimm, E., Hu, F. B. (2005). Dairy consumption and risk of type 2 diabetes mellitus in men: A prospective study. Archives of Internal Medicine, 165, 997–1003

Jeyaraman, M. M., Abou-Setta, A. M., Grant, L., Farshidfar, F., Copstein, L., Lys, J., Gottschalk, T., Desautels, D., Czaykowski, P., Pitz, M., & Zarychanski, R. (2019). Dairy product consumption and development of cancer: an overview of reviews. BMJ Open, 9(1), e023625. https://doi.org/10.1136/bmjopen-2018-023625

Jin, S., & Je, Y. (2022). Dairy consumption and total cancer and cancer-specific mortality: A meta-analysis of prospective cohort studies. Advances in Nutrition (Bethesda, Md.), 13(4), 1063–1082. https://doi.org/10.1093/advances/nmab135

Lu, W., Chen, H., Niu, Y., Wu, H., & Wu, Y. (2016). Dairy products intake and cancer mortality risk: a meta-analysis of 11 population-based cohort studies. Nutrition Journal, 15, 91. https://doi.org/10.1186/s12937-016-0210-9

Mena-Sánchez, G., Becerra-Tomás, N., Babio, N., Salas-Salvadó, J. (2019). Dairy product consumption in the prevention of metabolic syndrome: A systematic review and meta-analysis of prospective cohort studies. Advances in Nutrition,10, S144–53.

Mishali, M., Prizant-Passal, S., Avrech, T., Shoenfeld, Y. (2019). Association between dairy intake and the risk of contracting type 2 diabetes and cardiovascular diseases: A systematic review and meta-analysis with subgroup analysis of men versus women. Nutrition Reviews, 77, 417–429. http://doi.org/10.1093/nutrit/nuz006.

Missmer, S., Smith-Warner, S., Spiegelman, N., Yaun, S.-S., Adami, H.-O., Beeson, W. L., Brandt, P.A.V.D., Fraser, G., Freudenheim, J. L., Goldbohm, R. A., et al. (2002). Meat and dairy food consumption and breast cancer: A pooled analysis of cohort studies. International Journal of Epidemiology, 31, 78–85. http://doi.org/10.1093/ije/31.1.78.

Mitri, J., Tomah, S., Mottalib, A., Salsberg, V., Ashrafzadeh, S., Pober, D. M., Eldib, A. H., Tasabehji, M. W., Hamdy, O. (2020). Effect of dairy consumption and its fat content on glycemic control and cardiovascular disease risk factors in patients with type 2 diabetes: A randomized controlled study. American Journal of Clinical Nutrition, 112, 293–302. http://doi.org/10.1093/ajcn/nqaa138. 

Ratajczak, A. E., Zawada, A., Rychter, A. M., Dobrowolska, A., & Krela-Kaźmierczak, I. (2021). Milk and dairy products: Good or bad for human bone? Practical dietary recommendations for the prevention and management of osteoporosis. Nutrients, 13(4), 1329. https://doi.org/10.3390/nu13041329

Rizzoli, R. (2022). Dairy products and bone health. Aging Clinical and Experimental Research, 34(1), 9–24. https://doi.org/10.1007/s40520-021-01970-4

Schmidt, K. A., Cromer, G., Burhans, M. S., Kuzma, J. N., Hagman, D. K., Fernando, I., Murray, M., Utzschneider, K. M., Holte, S., Kraft, J., et al. (2021). The impact of diets rich in low-fat or full-fat dairy on glucose tolerance and its determinants: A randomized controlled trial. American Journal of Clinical Nutrition, 113, 534–547. https://doi.org/10.1093/ajcn/nqaa301

Tian, S., Xu, Q., Jiang, R., Han, T., Sun, C., & Na, L. (2017). Dietary protein consumption and the risk of type 2 diabetes: A systematic review and meta-analysis of cohort studies. Nutrients, 9(9), 982. https://doi.org/10.3390/nu9090982.

 Visioli, F., & Strata, A. (2014). Milk, dairy products, and their functional effects in humans: a narrative review of recent evidence. Advances in Nutrition (Bethesda, Md.), 5(2), 131–143. https://doi.org/10.3945/an.113.005025

Wang, W., & Wu, Y., Zhang, D. (2016). Association of dairy products consumption with risk of obesity in children and adults: A meta-analysis of mainly cross-sectional studies. Annals of Epidemiology, 26(12), 870–882.e2.