Lack of selenium increases the toxicity of pain-relieving medication

Millions of people take painkillers such as Panadol or Calpol that contain paracetamol, and an estimated one billion people or so lack selenium due to nutrient-depleted farmland. This is an unfortunate cocktail because being deficient of selenium increases the risk of using paracetamol, so even the recommended dosage burdens the liver to such an extent that it causes toxicity and increase the risk of side effects. This was demonstrated in a collaborative study carried out by Bath University in England and Southwest University in China.

Paracetamol is a widely used pain-reliving and fever-reducing over-the-counter remedy. Paracetamol affects the synthesis of neurotransmitters that are forwarded to the central nervous system. There are also prescription medicines against strong pain that combine paracetamol with codeine, which is an opioid. It is extremely important not to exceed the recommended dose for paracetamol, which is four grams per day for adults, or the same as two 500 mg tablets four times daily. If this dose is exceeded, for instance in the case of attempted suicide, it may result in irreversible, painful and potentially lethal damage to the liver and other internal organs. According to new science, even the current maximum dose for paracetamol for adults can be too high.

Lack of selenium increases the toxicity of paracetamol

The scientists from Bath University in England and Southwest University in China have discovered that lack of selenium affects the rate at which paracetamol is metabolized by the body. In other words, ingesting the maximum four-gram daily dose of paracetamol in a day may be dangerous for people with low selenium levels. According to Dr. Charareh Pourzand from Bath University, who headed the collaborative study, selenium-deficient people may have difficulty with metabolizing paracetamol fast enough to protect their livers. This may cause a paracetamol overdose, even in cases where they are adhering to the proper guidelines for safe use of the drug.

In the case of selenium deficiency, the liver is attacked by harmful free radicals

Selenium is part of the powerful antioxidant enzymes called GPx that help counteract oxidative stress, which is an imbalance between harmful free radicals and protective antioxidants. We humans produce free radicals as a natural part of our energy metabolism, but also during detoxification, infections, and other metabolic processes. However, the free radicals must be controlled so they do not attack our cells.
When we lack selenium, the body is unable to produce sufficient amounts of selenium-containing antioxidant enzymes (selenoproteins) and that increases the free radical burden on the liver. Because the liver is the primary organ involved in breaking down paracetamol, it is exposes to oxidative stress. As a result, there may be damage to the cell membranes, DNA, and important proteins. Needless to say, the risk of damage goes up with regular consumption of paracetamol to quell recurrent or persistent pain. Dr. Pourzand therefore underlines the importance of eating a healthy diet with adequate selenium, yet that can be difficult even if you follow the official dietary guidelines.

Selenium sources and causes of the widespread selenium deficiency

You get selenium from oily fish, offal, eggs, brown rice, Brazil nuts, mushrooms, and certain other sources. However, in places such as Great Brian, Scandinavia, New Zealand, the Northeastern regions of China, and Southeastern states of America the farmland is low in selenium and that affects the entire food chain. Furthermore, the use of pesticides combined with altered eating habits contribute to the widespread problems with selenium deficiency. An estimated one billion people worldwide are believed to lack selenium. That is the same as one in seven global citizens.

Official and optimal recommendations

Dr. Pourzand also points out that one must be careful not to get too much selenium from supplements. One must therefore strive to get the exact right amount.
In Denmark, the official reference intake level (RI) for selenium is 55 micrograms, but numerous studies suggest that humans need around 90-100 micrograms to saturate selenoprotein P, which is used as a marker of the body’s selenium status. The European Food Safety Authority (EFSA) has established a safe upper intake level of 300 micrograms daily. In any case, it is important to get a healthy diet, as the selenium-containing proteins work with other nutrients such as vitamin E.

Referencer:

Li, J et al. Selenium Status in Diet Affects Acetaminophen-induced Hepatotoxicity via Interruption of Redox Environment. Antioxidants and Redox Signaling. 2020

Medical News Today. Study shows link between selenium-deficiency diet and paracetamol toxicity. Aug 5 2020

Lutz Shomburg. Dietary Selenium and Human Health. Nutrients 2017

https://da.wikipedia.org/wiki/Paracetamol

https://www.sst.dk/da/nyheder/2020/foraeldre-kan-give-deres-boern-paracetamol-som-tablet

https://www.med24.dk/bliv-klog-paa-laegemidlet-paracetamol