Hikers, Don’t Get Lost in The Trek’s Tuna Myths
If a recent piece from The Trek (“Could This Thru-Hiker Staple Give You Mercury Poisoning?” by James Townsend) is aimed at making the hiking community smarter on nutrition then it has wildly missed the mark, instead amplifying long-discredited, fear-mongering narratives that could scare an entire community off an affordable, nutrient-rich protein.
The author of the piece is a self-described “social media coordinator” and “photojournalist”—not a scientist or a nutrition expert. So it’s no surprise that many of the claims made about tuna and mercury are false, misleading, or taken out of context. It’s worth dealing with a few of them in order:
First, the author claims that mercury “enters the ocean primarily from human activities.” This is a tell-tale clue that much of what’s to follow will be distorted, for two reasons. First of all, it’s not true. As one science writer summarizes the evidence: “Industrial mercury emissions plummeted 73 percent from 2007 to 2019 in the US and 30 percent globally between 1990 and 2010—significantly reducing the amount of mercury that accumulates in the fish we eat.” Indeed, the United Nations concluded about 70 percent of the methylmercury found in seafood is naturally occurring, the result of volcanic activities and other natural processes.
Why does it matter where the tiny amounts of mercury in seafood are coming from? Aren’t they a danger either way? That gets us to the second-of-all: The fact that most of the mercury in our oceans is naturally occurring means that there has literally been trace amounts of mercury in sea life since the dawn of sea life.
In other words, if regular seafood consumption were causing an epidemic of mercury poisoning, we’d know about it by now. Both the data and common sense back this up. Consider that there is precisely zero evidence that populations like Japan’s—who eat about seven times as much fish per capita as Americans—are suffering from a hidden mercury crisis. In fact, Japan has the highest life expectancy in the world.
Next the author warns that while eating tuna “occasionally is generally considered safe…eating it daily for months, as some backpackers might” isn’t. He goes on at length: “That means if you are eating a single-serving white tuna packet every day on trail, you’re exceeding the recommended weekly limit by nearly seven times. Even with light tuna, eating more than two or three packets weekly is enough to push you beyond the safe range.”
Good news for tuna freaks in the hiking world: this is totally and unequivocally false.
Let’s stick to the facts. Let’s stick to the facts. First and most significantly, the federal dietary guidance the author cites on tuna is aimed specifically at pregnant women and those who may become pregnant—not the general public. Even that most sensitive group, moms, can safely eat up to 56 ounces of tuna—that’s a tuna sandwich for breakfast lunch and dinner, and then some. There is no—repeat no—restriction for the general population. And to suggest that there is, as the author does, is a mistake, and a consequential one. Let’s broaden things out: Average mercury content across U.S. seafood is roughly 0.072 ppm—about 14 times lower than the FDA’s level of concern (1.0 ppm) and over 100 times lower than the lowest levels ever associated with adverse effects. In other words, for ordinary consumers, the real-world risk from regular consumption of seafood—including canned and pouched tuna—is effectively zero.
And the facts on the ground bear that out. To this day, there have been no confirmed cases of methylmercury toxicity in the U.S. from the ordinary consumption of commercial seafood.
Period.
As for the difference between “white” (albacore) and “light” (skipjack) tuna, the FDA and EPA list both among the “good” or “best” choices in their advice to pregnant women, nursing mothers, and young children. Again, that’s for the most sensitive consumers, not the general public much less the average hiker. Whether you eat light or white tuna is primarily about your preferences in taste, texture, and subtle differences in nutrient content—not safety. For the general population, both remain healthy, affordable, and low-risk protein options.
By contrast, the kind of nitpicking between varieties only serves to confuse consumers and scare them off eating seafood altogether. Indeed, the biggest risk to populations like hikers comes from not eating enough seafood generally, due in part to alarmist articles like this one. That’s why most Americans eat less than half the recommended amount of seafood each week—and that missing out on fish means forfeiting proven health benefits.
Canned and pouched tuna is one of the most accessible, protein-dense, nutrient-packed options in the pantry. Wild-caught, shelf-stable, rich in omega-3s, B-vitamins, selenium and high-quality lean protein—there is a broad consensus that tuna provides real health value as part of a balanced diet.
The most honest part of the Trek posts comes in the form of an editorial disclaimer:
Ed. Note: We are hikers, not doctors. This advice is not intended to be a substitute for professional medical advice, diagnosis, or treatment. Always seek the advice of a qualified health care provider with any questions you may have regarding diet and medical conditions.
The hiking community would have been better off if they simply left it at that.