by Cy Willson
The Truth About Sardines
Joe Rogan recently said he suffered from arsenic toxicity from eating too much of a certain food. Can that really happen?
Arsenic toxicity from food or water occurs, but experiencing arsenic poisoning from eating sardines, as Joe Rogan said happened to him, is highly unlikely. Here’s why.
Arsenicals or Arsenic Species
Arsenic is a metalloid that exists in several chemical forms. Which form you ingest makes a dramatic impact on its potential toxicity.
Generally speaking, inorganic arsenic, and, in particular, trivalent arsenic, is considered the most toxic, followed by pentavalent arsenic. Inorganic arsenic occurs naturally in the Earth’s crust. It can make its way into food and water either via natural deposits or due to human activities (mining or arsenic-based pesticides).
Organic arsenic is considered much less toxic than inorganic arsenic, although trivalent organic arsenic metabolites are a potential exception. Some forms of organic arsenic, such as arsenobetaine, are actually considered non-toxic (1,2). These organic forms are more often encountered in organisms or foods that have metabolized inorganic arsenic to these less harmful forms or consumed them from lower trophic level organisms.
What’s in Sardines? Not All Arsenic is Alike.
Virtually all fish from the sea, including sardines, salmon, anchovies, cod, mackerel, tuna, and shellfish (even mushrooms), have a fairly significant amount of arsenic in their tissues. The vast majority consists of non-toxic arsenobetaine (1-3). The remainder, if present, consists of very small quantities of other methylated arsenicals, considered to have only moderate toxicity.
Inorganic arsenic – the form people refer to when mentioning actual arsenic poisoning – is not normally found in sardines or other seafood at significant concentrations (mollusks and shellfish can sometimes be the exception). Inorganic arsenic toxicity stems from contaminated groundwater or eating large amounts of contaminated food – rice or other contaminated crops, and sometimes animals fed contaminated feed.
There are, however, no documented cases of arsenic poisoning from sardines. The single case reported in the literature (and repeatedly cited in the lay press, unfortunately) was actually about an individual who reported consuming sardines while visiting his physicians. He specifically said that he believed he had arsenic poisoning (4). However, he couldn’t actually provide any can of sardines of the same brand when questioned and flaked out on the physicians when they tried to question him more. Not the most reliable patient and case report!
The physicians in that case evaluated only total arsenic levels in his urine rather than performing arsenic speciation analysis. This is what I suspect happened with Rogan.
So, whether it was an inorganic form (virtually impossible with sardines) versus another source isn’t possible to say. Although, confusingly, the authors state that this was a case of inorganic arsenic toxicity (without citing any evidence). As noted, inorganic arsenic isn’t found in sardines in any significant quantity outside of an unusual circumstance.
The fact that the physicians only evaluated total arsenic in the patient’s urine is also problematic. Even normal seafood consumption, especially within 24 hours of urine collection, can lead to total arsenic levels outside the normal range despite not actually consisting of any significant quantity of inorganic arsenic and with no indications of toxicity (5,6).
Ok, Sardines Are Fine. But What Foods Should I Avoid?
Interestingly, spirulina, a popular ingredient in many “greens” products, has elevated levels of inorganic arsenic. (I’d stick with Biotest’s Superfood (Buy at Amazon) instead.)
Typical culprits are rice, juices (apple), and chicken. You can reduce the level of inorganic arsenic in rice by boiling it more like you would pasta, using more water rather than the label directions say to use. For chicken, other than not eating three pounds per day, it’s not a bad idea to consume foods that help mitigate some of the harmful effects of arsenic, including fruits and vegetables, while making sure you’re getting enough protein, zinc, and vitamins C and E. Induced sweating via exercise and sauna may also be helpful.
Don’t Worry, Joe!
Sardines contain arsenic, but the vast majority is not the harmful type. You and Rogan shouldn’t worry about eating sardines or any other fish because of arsenic. Most likely, Rogan had total arsenic assayed without any speciation performed, which can lead to erroneous interpretations.
References
References
- Luvonga C, Rimmer CA, Yu LL, Lee SB. Determination of total arsenic and hydrophilic arsenic species in seafood. J Food Compost Anal. 2020 Nov 24;96(103729):10.1016/j.jfca.2020.103729. doi: 10.1016/j.jfca.2020.103729. PMID: 34092915; PMCID: PMC8174234.
- Taylor V, Goodale B, Raab A, Schwerdtle T, Reimer K, Conklin S, Karagas MR, Francesconi KA. Human exposure to organic arsenic species from seafood. Sci Total Environ. 2017 Feb 15;580:266-282. doi: 10.1016/j.scitotenv.2016.12.113. Epub 2016 Dec 24. PMID: 28024743; PMCID: PMC5326596.
- Schaeffer R, Soeroes C, Ipolyi I, Fodor P, Thomaidis NS. Determination of arsenic species in seafood samples from the Aegean Sea by liquid chromatography–(photo-oxidation)–hydride generation–atomic fluorescence spectrometry. Analytica chimica acta. 2005 Aug 15;547(1):109-18.
- Othman L, Nafadi A, Alkhalid SH, Mazraani N. Arsenic Poisoning due to High Consumption of Canned Sardines in Jeddah, Saudi Arabia. Cureus. 2021 Jan 19;13(1):e12780. doi: 10.7759/cureus.12780. PMID: 33628652; PMCID: PMC7890435.
- Navas-Acien A, Francesconi KA, Silbergeld EK, Guallar E. Seafood intake and urine concentrations of total arsenic, dimethylarsinate and arsenobetaine in the US population. Environ Res. 2011 Jan;111(1):110-8. doi: 10.1016/j.envres.2010.10.009. Epub 2010 Nov 19. PMID: 21093857; PMCID: PMC3073506.
- Choi BS, Choi SJ, Kim DW, Huang M, Kim NY, Park KS, Kim CY, Lee HM, Yum YN, Han ES, Kang TS, Yu IJ, Park JD. Effects of repeated seafood consumption on urinary excretion of arsenic species by volunteers. Arch Environ Contam Toxicol. 2010 Jan;58(1):222-9. doi: 10.1007/s00244-009-9333-8. Epub 2009 May 24. PMID: 19466477.
…sad to say he works out himself you’d think he would have some common sense.