Casein

Cow’s milk dairy products contain casein

Many people have difficulty digesting dairy products because of lactose intolerance. This is an inability to break down the milk sugar, lactose, causing digestive distress. Most of us (depending on genetics) lose the enzyme that breaks down lactose when we are very young children.1 Humans did not evolve to continue digesting milk after weaning, and only a few thousand years or so (a short time period, evolutionarily speaking) did some of us start consuming the milk of another species: cows.

While lactose intolerance is a common discomfort, some people have an allergy to the milk proteins. Casein is the primary protein in milk, making up 80 percent of milk protein. The remaining 20 percent consists of whey, but casein is more commonly allergenic and causes inflammation.

Cross-reactivity with gluten, and autoimmunity

Casein is molecularly similar to gluten. Because of this, many people have cross-reactivity to both proteins if they have an antibody response to one or the other.2 This means that if you have celiac disease or an allergy to gluten, consuming dairy can cause the same symptoms. For this reason, it is important to eliminate both dairy and gluten at the same time.

Additionally, these antibodies to wheat and dairy can cross-react to neural antigens in the brain, potentially leading to neural autoimmunity.3 Research has even identified a specific autoimmune connection to these dietary proteins affecting a subset of patients with autism, in which autoantibodies attack the cerebral cells that control motor movement and the release of GABA.4

Milk protein allergies can also increase autoantibodies to folate receptors in the central nervous system, leading to folate deficiencies that cause oxidative stress in some children with ASD, affecting speech processing and social-emotional behavior.5-6

Elevated antibodies and immune sensitivity to casein have also been associated with schizophrenia, recent-onset psychosis and bipolar disease.7-8 Children with a milk allergy are also twice as likely to have a psychiatric diagnosis like ADHD or oppositional defiant disorder (ODD).9

Cow, sheep or goat milk? A1 and A2 proteins

Casein comes in two forms – A1 protein, which is found in American Holstein cow’s milk, and A2, which is found in the milk of Jersey cows as well as sheep’s milk and goat’s milk. The A1 protein is the less-tolerated form of milk protein. Many people who cannot tolerate cow’s milk do well on sheep’s or goat’s milk, and this is why. A1 casein releases an opiate-stimulating compound called casomorphin, which attributes to the addictiveness of dairy products.10 Casomorphin is also implicated in contributing to sudden infant death syndrome by inducing sleep apnea.11

When removing casein from the diet, it’s important to remove all dairy products for a period of time. (Though ghee, or clarified butter, is generally well-tolerated as milk proteins have been removed.) Later, once immune responses have resolved, you can try reintroducing sheep’s or goat’s milk products, which contain the less-reactive form of casein, A2. While some people may tolerate these foods, others may not, and will need to avoid all dairy indefinitely.

References

  1. Swallow D. M. (2003). Genetics of lactase persistence and lactose intolerance. Annual review of genetics, 37, 197–219. https://doi.org/10.1146/annurev.genet.37.110801.143820
  2. Vojdani, A., Tarash, I. (2013). Cross-reaction between gliadin and different food and tissue antigens. Food and nutrition sciences, 4 (1) 20-32. http://dx.doi.org/10.4236/fns.2013.41005
  3. Vojdani, A., Kharrazian, D., & Mukherjee, P. S. (2013). The prevalence of antibodies against wheat and milk proteins in blood donors and their contribution to neuroimmune reactivities. Nutrients, 6(1), 15–36. https://doi.org/10.3390/nu6010015
  4. Vojdani, A., O’Bryan, T., Green, J. A., Mccandless, J., Woeller, K. N., Vojdani, E., Nourian, A. A., & Cooper, E. L. (2004). Immune response to dietary proteins, gliadin and cerebellar peptides in children with autism. Nutritional neuroscience, 7(3), 151–161. https://doi.org/10.1080/10284150400004155
  5. Ramaekers, V. T., Sequeira, J. M., Blau, N., & Quadros, E. V. (2008). A milk-free diet downregulates folate receptor autoimmunity in cerebral folate deficiency syndrome. Developmental medicine and child neurology, 50(5), 346–352. https://doi.org/10.1111/j.1469-8749.2008.02053.x
  6. Frye, R.E., Sequeira, J., Quadros, E., Quadros, E.V,  James, S.J., & Rossignol, D.A.  (2013). Cerebral folate receptor autoantibodies in autism spectrum disorder. Mol psychiatry, 18, 369–381. https://doi.org/10.1038/mp.2011.175
  7. Severance, E. G., Gressitt, K. L., Yang, S., Stallings, C. R., Origoni, A. E., Vaughan, C., Khushalani, S., Alaedini, A., Dickerson, F. B., & Yolken, R. H. (2014). Seroreactive marker for inflammatory bowel disease and associations with antibodies to dietary proteins in bipolar disorder. Bipolar disorders, 16(3), 230–240. https://doi.org/10.1111/bdi.12159
  8. Severance, E. G., Dickerson, F. B., Halling, M., Krivogorsky, B., Haile, L., Yang, S., Stallings, C. R., Origoni, A. E., Bossis, I., Xiao, J., Dupont, D., Haasnoot, W., & Yolken, R. H. (2010). Subunit and whole molecule specificity of the anti-bovine casein immune response in recent onset psychosis and schizophrenia. Schizophrenia research, 118(1-3), 240–247. https://doi.org/10.1016/j.schres.2009.12.030
  9. Topal, E., Catal, F., Soylu, N., Ozcan, O. O., Celiksoy, M. H., Babayiğit, A., Erge, D., Karakoç, H. T., & Sancak, R. (2016). Psychiatric disorders and symptoms severity in pre-school children with cow’s milk allergy. Allergologia et immunopathologia, 44(5), 445–449. https://doi.org/10.1016/j.aller.2016.03.001
  10. Brogan, K. Two foods that may sabotage your brain. https://kellybroganmd.com/two-foods-may-sabotage-brain/
  11. Wasilewska, J., Sienkiewicz-Szłapka, E., Kuźbida, E., Jarmołowska, B., Kaczmarski, M., & Kostyra, E. (2011). The exogenous opioid peptides and DPPIV serum activity in infants with apnoea expressed as apparent life threatening events (ALTE). Neuropeptides. 45. 189-95. 10.1016/j.npep.2011.01.005
©️ 2021 Angie Spinelli