Dairy’s Role in Parkinson’s Disease

Mar 30, 2023

There are countless reasons to remove dairy products from your diet, especially to benefit your health. There are links to lifestyle diseases like cardiovascular disease and diabetes, as well as other health conditions like prostate cancer, breast cancer, and asthma. Something less often discussed are associations between diet and neurological conditions. 

We’re looking at the most current literature on dairy related to Parkinson’s disease, a progressive brain disorder that results in involuntary tremors, shaking, loss of balance, and difficulty talking.1 This condition remains much of a mystery, and its cause is still unknown to physicians and scientists.

The Honolulu Heart Study

The Honolulu Heart Study has been a major contributor to the science community’s understanding of Parkinson’s. It is considered one of the largest epidemiological studies of Parkinson’s to date.

The data suggests drinking greater than 16 ounces of cow’s milk per day more than doubled the chance of developing Parkinson’s, compared to drinking no cow’s milk. Calcium (whether from dairy foods or non-dairy foods) was ruled out as not affecting risk, suggesting milk itself is the culprit behind the elevated risk of Parkinson’s.2

Repeated results

We always want to look at the big picture and not single out one study, even if it is highly respected in the community. When it comes to the association of dairy consumption and Parkinson’s disease, the results have been repeated by additional research teams. There are three noteworthy studies with similar results:

  • The American Cancer Society’s Cancer Prevention Study II Nutrition Cohort also saw an elevated risk of developing Parkinson’s based on dairy product consumption. This research showed Parkinson’s developed 1.8 times more in men and 1.3 times more in women who consumed milk.3
  • A prospective cohort study looking at over 26,000 participants, called the EPIC-Greece cohort, also found a strong positive association between consuming milk specifically and developing Parkinson’s disease.4
  • A study combining the data of two prospective cohort studies, which included 125,000+ participants, found a positive association between low-fat dairy products, mainly skim and low-fat milk, and developing Parkinson’s.5

Collectively, these four studies all offer the same conclusion: there is an association between dairy product consumption and Parkinson’s disease risk.

What is in milk?

Researchers have not been able to identify what specifically is in dairy milk that is increasing the risk of developing Parkinson’s disease, however there is ongoing research to try to determine the cause. 

The researchers from the previously mentioned American Cancer Society’s Cancer Prevention Study II Nutrition Cohort suggest an interesting correlation between neurotoxic chemicals and dairy products. There is already evidence that exposure to certain pesticides may increase Parkinson’s risk. Organochlorines, polychlorinated biphenyls, and dieldrin have been found in the autopsied brains of patients with Parkinson’s disease, and these contaminants have also been found in dairy products.3 However, more research is definitely needed before coming to any conclusions on if there is a causal relationship.

Genetic factors

As we know, genetics play a huge factor in one’s ability to digest lactose beyond childhood. People with European ancestry are more likely to have the lactase persistence genetic variant rs4988235, which allows them to continue digesting lactose. Research from two separate studies has found that those with this gene also have higher rates of Parkinson’s.6,7 At this time, science cannot determine whether this gene is the reason for an increased risk of developing Parkinson’s. It may well be that individuals with this gene tend to consume more dairy products because they are not sickened by them (unlike over two-thirds of the population who are lactose intolerant) and therefore have more exposure to the potentially harmful components.


Reliable research studies have found a correlation between consuming higher quantities of dairy products, especially milk, and increased odds of developing Parkinson’s disease. As we know, correlation does not necessarily mean causation. However, when there are countless incredible dairy-free options available, why wouldn’t you make the switch? There are already so many benefits to your health when removing dairy from your diet, and decreasing your risk of developing Parkinson’s disease may be one more to add to the list.

Not sure where to begin? Check out our Ultimate Guide to Dairy-Free Alternatives.


References →

  1. Parkinson’s Disease: Causes, Symptoms, and Treatments. National Institute on Aging. https://www.nia.nih.gov/health/parkinsons-disease. Updated 2022. Accessed Mar 23, 2023 
  2. Morens DM, Davis JW, Grandinetti A, Ross GW, Popper JS, White LR. Epidemiologic observations on Parkinson’s disease: incidence and mortality in a prospective study of middle-aged men. Neurology. 1996;46(4):1044-1050. doi:10.1212/wnl.46.4.1044
  3. Chen H, O’Reilly E, McCullough ML, et al. Consumption of dairy products and risk of Parkinson’s disease. Am J Epidemiol. 2007;165(9):998-1006. doi:10.1093/aje/kwk089
  4. Kyrozis A, Ghika A, Stathopoulos P, Vassilopoulos D, Trichopoulos D, Trichopoulou A. Dietary and lifestyle variables in relation to incidence of Parkinson’s disease in Greece. Eur J Epidemiol. 2013;28(1):67-77. doi:10.1007/s10654-012-9760-0

Hughes KC, Gao X, Kim IY, et al. Intake of dairy foods and risk of Parkinson disease. Neurology. 2017;89(1):46-52. doi:10.1212/WNL.0000000000004057

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