Wilson disease is an illness in which copper accumulates pathologically in the body, resulting in a range of symptoms—from liver disease to neurological dysfunction. The disease is named after Dr. Samuel Alexander Kinnier Wilson, who first wrote about it in 1912.

Dr. Wilson described the most notable manifestations of the disease and proposed it be called “progressive lenticular degeneration.” The name did not stick and the disease was eventually named after him. 

“There is great variability in the symptoms that patients with Wilson disease present with, and for that reason it is sometimes referred to as the great masquerader,” Mulligan and Bronstein wrote in Neurologic Clinics.

Fortunately, “the great masquerader,” when unmasked, can be effectively treated with anti-copper therapies. There are a number of medications approved for treating Wilson disease, all of which remove copper from the body in one way or another. 

Reducing Copper Buildup 

Aside from copper-chelating medications, dietary restriction has historically been considered an important aspect of controlling Wilson disease. This strategy relies on restricting copper intake to reduce its buildup in the body. 

“As [Wilson disease] is characteristically a problem of copper accumulation, it has been supposed that long-term mainstay treatment should include a copper restricted diet,” Russell and colleagues wrote in the European Journal of Clinical Nutrition. 

The typical dietary advice for patients with Wilson disease is to consume fewer copper-rich foods such as shellfish, liver, chocolate, nuts, mushrooms, etc. It is worth noting that most water filters do not filter out copper; a potential solution for this is to run the water to flush the pipes, which can significantly reduce copper levels. 

Teufel-Schäfer and colleagues conducted a literature review on whether there was clear evidence supporting a low copper diet for patients with Wilson disease, incorporating articles indexed in PubMed involving Wilson disease and nutrition through May 2022.

They reported that evidence shows the copper absorption rate is lower when patients consume a high-copper diet compared to a low-copper diet—absorption rates ranged from 56% with low-copper content to 12% with high-copper content. In other words, while more copper is absorbed in a high-copper diet, it is only due to relative copper content and not to a higher absorption rate. 

Teufel-Schäfer and colleagues pointed out that while American and European guidelines stress the importance of avoiding foods with high copper content, particularly in the first year of treatment, foods that have high copper content are typically not part of a newborn diet. This is, of course, only applicable if the disease is diagnosed early in life. 

“In order to achieve a too high copper intake, restricted foods would have to be consumed in large amounts,” Teufel-Schäfer et al wrote. 

In other words, even in adults, patients would have to be consuming copper-rich foods in very high amounts for it to matter in the context of Wilson disease, keeping in mind that individuals still need around 1.3-1.6 mg of copper per day. This is roughly equivalent to 625 mg milk chocolate, 320 g peanut butter, or 440 g mushrooms. 

American guidelines state that a vegetarian diet can delay disease onset and control progression by reducing copper bioavailability. This is based on a study of 2 patients who did not adhere to drug therapy but consumed a lacto-vegetarian diet. However, Teufel-Schäfer and colleagues pointed out that low copper intake can only prevent copper reaccumulation and not solve the more pertinent problem of a lack of copper excretion. 

“It should be noted . . . that the pathology of [Wilson disease] is not caused by an excessive intake of copper, but in a hepatocellular excretory disorder,” they wrote. 

Is Dietary Control Sound Advice? 

There is another downside to prescribing dietary control to individuals with Wilson disease—patient anxiety. Studies have shown that advising patients to restrict their intake of all copper-containing foods can cause considerable second-guessing and anxiety among patients. This is despite very limited evidence that food restriction has an impact on the course of the disease (with the exception of shellfish and liver). 

“Patients should be reassured that all they need to avoid is shellfish and liver during the first year of therapy, and from then on they can have one meal/week of shellfish, but only a very limited amount of liver,” Russell and colleagues wrote in the European Journal of Clinical Nutrition. “Further exclusions should be discouraged.” 

It is equally important for physicians to ensure that patients are not so careful with their diet that they end up with a compromised nutritional status, with malnutrition being the worst-case scenario. Instead, the aim should always be a well-balanced diet. 

In conclusion, while some restrictions in the diet make sense, there is no evidence for dietary restriction on all copper-containing foods. Patients should be made to understand that copper is still an integral part of their diet and that moderation is key. A well-balanced diet can be planned with the help of a dietitian as part of a multidisciplinary team. 

References

Teufel-Schäfer U, Forster C, Schaefer N. Low copper diet—a therapeutic option for Wilson disease? Children (Basel). 2022;9(8):1132. doi:10.3390/children9081132

Russell K, Gillanders LK, Orr DW, Plank LD. Dietary copper restriction in Wilson’s diseaseEur J Clin Nutr. 2018;72(3):326-331. doi:10.1038/s41430-017-0002-0

Mulligan C, Bronstein JM. Wilson disease: an overview and approach to managementNeurol Clin. 2020;38(2):417-432. doi:10.1016/j.ncl.2020.01.005