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Writer's pictureIsabel Hemmings

Should we eat dairy foods?

For many years, saturated fats have been feared and avoided, so many people have been cautious about eating foods high in saturated fat, such as dairy foods, like milk, cheese and yoghurt. However a mountain of evidence now suggests that rather than being a risk, dairy foods are actually protective and beneficial for health. Here we review the most recent evidence which shows that as well as being good for your bones, dairy foods may reduce your risk of cardiovascular disease, some cancers, dementia and metabolic conditions such as Obesity, and Type 2 Diabetes.


Saturated fat, dairy foods and health

 

Over recent decades, in an effort to protect us from heart disease, we were advised to reduce our intake of saturated fats. Since the 1960s our intake of dietary fat fell 50% - from around 125g/d to less than 83g/d today and our intake of saturated fat fell from an average of 55g/day to around 30g/day. However, despite our reduction in fat consumption, especially saturated fat consumption, the aim of reducing cardiovascular disease through this measure has been largely unsuccessful, and the burden of many diseases, including obesity and type 2 diabetes has increased substantially.

 

Researchers are now considering why the reduction in saturated fat has not had the desired effect on improving health and many scientists are now calling for changes to be made to dietary guidelines which advise populations to lower saturated fat intake.

 

In particular, researchers point to strong evidence that saturated fats found in dairy foods, particularly in fermented dairy foods such as cheese  and yoghurt, are actually protective for health. They suggest that we are better considering whole foods, rather than components of foods (such as saturated fats), when offering guidance on a healthy diet.

 


The evidence on how dairy foods impact on health


There is now ample evidence that dairy foods make a positive contribution to a healthy diet, and some of this research is summarised below. The evidence detailed below is based on large numbers of studies and in-depth analysis, including:

  • Systematic reviews - which assess all available research studies and use clearly defined, systematic methods to obtain answers to a specific question.

  • Meta-analyses use statistical processes to analyse and combine results from several similar studies.

  • Umbrella reviews are systematic assessments of many systematic reviews and meta-analyses on a specific research topic. 


It should be noted that all the evidence is based on associations between dairy foods and disease, and this cannot prove a definite causal link. However, these studies involve large numbers of participants and therefore these associations are likely to be meaningful.



1.    Cardiovascular disease and stroke

 

There is now substantial evidence showing that dairy foods are not only not a risk factor for cardiovascular disease, but they are actually protective against such diseases:

 

Total dairy intake and risk of cardiovascular disease


  • In 2016, an assessment of the totality of evidence at that point concluded that milk and dairy products were associated with a reduced risk of cardiovascular disease, particularly stroke.

  • In the same year a meta-analysis of prospective cohort studies found total dairy intake, fermented milk and cheese intake to be significantly associated with a lower risk of stroke.

  • In 2017 a meta-analysis of 29 cohort studies involving 938,465 participants found no association between dairy consumption and health outcomes of mortality, Coronary Heart Disease (CHD) or Cardiovascular disease (CVD). This study also found an inverse association between total fermented dairy (including sour milk products, cheese or yoghurt) and mortality and CVD risk. This means that the more fermented dairy consumed, the lower the risk of CVD

  • In 2018 a systematic review and meta-analyses of prospective cohort studies found that total dairy did not increase risk of CHD. They concluded that dairy products are either neutral or protective against the risk of cardiometabolic diseases.

  • In 2019 an umbrella review of observational studies found  ‘convincing and probable’ evidence that dairy consumption decreased risk of cardiovascular disease, fatal stroke and hypertension.

 

Milk and cardiovascular disease


  • One systematic review and meta-analysis found that an increment of 200g of milk was associated with a 7% lower risk of stroke

  • The 2018 systematic review on total dairy found that milk intake, specifically, did not increase risk of CVD. They also found that milk was protective against stroke.

  • A 2021 umbrella review by Zhang et al of 41 meta-analyses on milk consumption found that 200ml (one cup) of milk per day was associated with a lower risk of CVD, stroke and hypertension.

They concluded  that milk does more good than harm for human health.


Cheese and cardiovascular disease


In 2021 a systematic review and meta-analysis of cohort studies published in Nature, reviewed the association between total dairy intake and risk of major atherosclerotic CVD (CHD and ischemic stroke). The study found an inverse association between cheese consumption and CHD risk


In 2023 an umbrella review of 54 meta-analyses found cheese consumption to be inversely associated with  all-cause mortality, cardiovascular disease, CHD and stroke. This means that eating cheese reduced risk for these diseases. 


Diagram 1 showing relationship between cheese intake and the risk of stroke



2.    Cancer

 

Dairy foods may also be protective against some, although not all, forms of cancer. An umbrella review of observational studies found ‘convincing and probable evidence’  that dairy foods decreased the risk of colorectal cancer. The protective effect of milk specifically was also shown by Zhang and colleagues in 2021.

 

Dairy foods are also shown as likely to be protective against breast cancer (Godos 2019). Cheese consumption has specifically been shown to be inversely associated with oestrogen receptor( ER) breast cancer, so risk reduced with consumption of cheese and there is evidence dairy intake may also be protective against bladder cancer and gastric cancer, (Thorning 2016).

 

However, there is evidence that whole milk in men may contribute to elevated prostate cancer mortality risk, with a greater intake of whole milk associated with an increased risk of prostate cancer mortality.



3.    Metabolic Syndrome, type 2 Diabetes and  Obesity

 

A 2016 review found milk and dairy products were associated with a neutral or a decreased risk of Type 2 diabetes. A 2019 umbrella review of observational studies found that dairy consumption was associated with a possible reduced risk of Metabolic Syndrome and Type 2 Diabetes and Zhang et al 2021 found a beneficial association between milk consumption and Type 2 Diabetes.


In 2023 another umbrella review found cheese consumption to be inversely associated with Type 2 Diabetes. These researchers also found milk intake (200mls/ day) to lower the risk of obesity.


Yoghurt is also shown to lower the risk of Type 2 Diabetes, with greater consumption of yoghurt being linked to a lower risk of Type 2 Diabetes


Figure 2 Yogurt consumption and risk of Type 2 Diabetes




4. Bone and dental health


Milk and dairy intake have long been considered beneficial for bone and dental health.

Dairy foods are an excellent source of calcium, phosphorus, protein and other nutrients that are important both for bone health. Calcium is critical for strong bones and our skeleton and dairy foods are known as beneficial for bone mineral density (Thorning 2016) and the prevention of osteoporosis. Milk and other dairy foods are the most the most readily available sources of calcium and evidence strongly supports the benefits of dairy foods for bone and muscle health. 200mls of milk per day has been shown to lower the risk of osteoporosis Zhang et al ( 2021) and cheese consumption has been shown to reduce the risk of fractures Zhang 2023).


Dairy foods have also long been recognised as important for dental health, and there are concerns that dairy alternatives may not provide the same protective benefits



5.   Dementia

 

A systematic review published this year found an inverse association between dairy intake and cognitive decline or dementia. Cheese may also be protective against dementia as consumption has been found to be inversely associated with dementia ( Zhang 2023) and milk consumption has a beneficial association with Alzheimers Disease (Zhange 2021).


In Conclusion


There is strong evidence that dairy foods have positive health benefits and contribute to protect against many diseases. The evidence on the positive impact of dairy foods on cardiovascular health is of particular importance given that many people have feared fats found in dairy foods due to the suggestion that saturated fats are bad for the heart. Dairy foods are beneficial for bone and dental health and seemingly protective against dementia. Dairy foods may also be protective against some cancers, including colorectal and some breast cancers, however whole milk may increase risk of prostate cancer.


Some references


Astrup A, Geiker NRW, Magkos F. Effects of Full-Fat and Fermented Dairy Products on Cardiometabolic Disease: Food Is More Than the Sum of Its Parts. Adv Nutr. 2019 Sep 1;10(5):924S-930S. doi: 10.1093/advances/nmz069. PMID: 31518411; PMCID: PMC6743821.

 

de Goede, J., Soedamah-Muthu, S. S., Pan, A., Gijsbers, L. & Geleijnse, J. M. Dairy consumption and risk of stroke: a systematic review and updated dose-response meta-analysis of prospective cohort studies. J. Am. Heart Assoc. 5, e002787 (2016).

 

Hu D, Huang J, Wang Y, Zhang D, Qu Y. Dairy foods and risk of stroke: a meta-analysis of prospective cohort studies. Nutr Metab Cardiovasc Dis. 2014 May;24(5):460-9. doi: 10.1016/j.numecd.2013.12.006. Epub 2013 Dec 25. PMID: 24472634. 

 

Guo, J. et al. Milk and dairy consumption and risk of cardiovascular diseases and all-cause mortality: dose-response meta-analysis of prospective cohort studies. Eur. J. Epidemiol. 32, 269–287 (2017).

 

Jakobsen, M.U., Trolle, E., Outzen, M. et al. Intake of dairy products and associations with major atherosclerotic cardiovascular diseases: a systematic review and meta-analysis of cohort studies. Sci Rep 11, 1303 (2021). https://doi.org/10.1038/s41598-020-79708-x

 

Godos, J., Tieri, M., Ghelfi, F., Titta, L., Marventano, S., Lafranconi, A., … Grosso, G. (2019). Dairy foods and health: an umbrella review of observational studies. International Journal of Food Sciences and Nutrition71(2), 138–151. https://doi.org/10.1080/09637486.2019.1625035

 

 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 Nov 22;60:32527. doi: 10.3402/fnr.v60.32527. PMID: 27882862; PMCID: PMC5122229.

 

Mingjie Zhang et al 2023 Cheese consumption and multiple health outcomes: an umbrella review and updated meta-analysis of prospective studies,

Advances in Nutrition, Volume 14, Issue 5,2023,Pages 1170-1186,ISSN 2161-8313,https://doi.org/10.1016/j.advnut.2023.06.007.

 

Lu W, Chen H, Niu Y, Wu H, Xia D, Wu Y. Dairy products intake and cancer mortality risk: a meta-analysis of 11 population-based cohort studies. Nutr J. 2016 Oct 21;15(1):91. doi: 10.1186/s12937-016-0210-9. PMID: 27765039; PMCID: PMC5073921.(prostate cancer)

 

Zhang X, Chen X, Xu Y, Yang J, Du L, Li K, Zhou Y. Milk consumption and multiple health outcomes: umbrella review of systematic reviews and meta-analyses in humans. Nutr Metab (Lond). 2021 Jan 7;18(1):7. doi: 10.1186/s12986-020-00527-y. PMID: 33413488; PMCID: PMC7789627.

 

Soedamah-Muthu SS, de Goede J. Dairy Consumption and Cardiometabolic Diseases: Systematic Review and Updated Meta-Analyses of Prospective Cohort Studies. Curr Nutr Rep. 2018 Dec;7(4):171-182. doi: 10.1007/s13668-018-0253-y. PMID: 30406514; PMCID: PMC6244750.

 

Fanny Villoz, et al Dairy Intake and Risk of Cognitive Decline and Dementia: A Systematic Review and Dose-Response Meta-Analysis of Prospective Studies,

Advances in Nutrition,Vol 15, Issue  2024,100160,ISSN 2161-8313,

 

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