Tuna Benefits + Side Effects

By Adriane Marie •  Updated: 03/03/22 •  13 min read
tuna benefits and side effects


Energy: tuna is bad for / increases the risk of anxiety, depression, heart disease impaired infant development, memory loss from PBCs, poor brain function, sickness from bacterial contamination, seafood is the number one cause of food poisoning in the United States, which leads to many side effects and causes extreme discomfort | tuna is good for / helps anemia prevention

Longevity: tuna is bad for / increases the risk of toxic chemicals known to cause cancer and brain degeneration, toxic contaminants and heavy metals from polluted water habitats, PBCs may cause liver damage, nervous system disorders, and fetal damage, dioxins, also linked to cancer and death, radioactive substances like strontium 90 and other dangerous contaminants like cadmium, mercury poisoning, lead, chromium, and arsenic, which can cause health problems such as kidney damage, impaired mental development and cancer, high levels of mercury can lead to Alzheimer’s, Parkinson’s, autism, mercury exposure can also lead to high blood pressure, an increased risk of heart attacks and higher LDL (bad) cholesterol

Appearance: tuna is good for / helps muscle building, weight loss

Tuna is…

a kids book about plant based eating
Teach Kids Where Our Food Comes From. Look Inside!


Water footprint: unknown

Carbon footprint: high, 6.1 CO2e to produce 1 kilogram or 2.2 pounds of canned tuna, a car driving equivalent of 14 miles or 22.5 kilometers

Destruction: high, tuna production is relatively destructive, negative impact on marine ecosystems, discarded fishing nets pollute oceans, fishing damages coral, sponges and poses severe threat to marine habitats, the Pacific ocean’s bluefin tuna population has dropped by 94% and is on the verge of extinction and continuing to consume bluefin tuna will contribute to its disappearance

Tuna is…


Kills: tuna, a type of saltwater fish

Harms: tuna, a type of saltwater fish, farmed fish spend their entire lives (up to two years) confined in tightly packed spaces, most farmed fish are predators and eat smaller fish, billions of wild fish must be caught in order to feed them, it can take several pounds of ocean fish to produce just one pound of farmed fish 

Indirectly kills or harms: sea-life, such as dolphins, sea turtles, protected fish, whales, seabirds etc. known as “bycatch”, unwanted marine life that unintentionally get caught, hooked and entangled in fishing nets

Tuna is…


Health and safety: hazardous, fishing workers are at risk of accident, injury, and death, reports show 20% of workers and almost 50% of trafficked victims have been injured on the job, injuries include cuts, broken bone, lost fingers, hands and limbs, head injuries, electrocutions, workers get caught in machinery, get thrown overboard, deaths are reported, boat decks are slippery and in constant motion, there can be hazardous machinery present

Living conditions: poor, fishing boats often lack toilets, intensive labor, rapid exhaustion, workers are held at sea and work against their will, they load catch onto bigger, commercial fishing boats in exchange for food and supplies, seafood caught illegally from slave worker boats gets mixed in with legal, commercial fishing boats in order to remain undetected, boats filled with trafficked migrants do not dock, sometimes for years, keeping slave workers unseen, trapped at sea, continuing forced labor and abuse, fishing industries around the world are responsible for systematic, illegal, fishing practices, human rights abuse, fishing workers are vulnerable to human trafficking and slave labor, in countries like Thailand (the third largest seafood exporter in the world), Burma, Indonesia, and Fiji seafood slavery is a major issue for migrant workers originally from Myanmar, Cambodia, Laos and Vietnam, seafood consumed in the United States is mostly from foreign sources

Wages: low, recruiters promise well paying jobs to poor, unskilled and vulnerable laborers, recruiters trick migrants into thinking they must work to pay off their debts, referred to as “debt peonage”, and little to no compensation for their work is given for long periods and maybe even years and are paid below the minimum wage 


Where is most tuna from?

The world’s top tuna exporter is Indonesia followed by Malta, Vietnam, South Korea, Spain, China, Turkey, Morocco, Croatia and Philippines. Thailand is the main supplier of canned tuna to foreign markets throughout the world. About 80% of the seafood consumed in the United States is imported. 

Is tuna nutritious?

Tuna is rich in Omega-3, Vitamin B12 and protein but extremely high in mercury and purines, which your body breaks down into uric acid. Additionally if fish farmed, antibiotics are always used.

tuna is acidic when fresh or canned.

acidic foods and alkaline diet benefits that improve ph levels

Is tuna alkaline or acidic? Tuna is acidic. What is the pH level of tuna? Tuna has a 6.0 pH level when fresh and 3.5 pH level when canned once digested. Fish is an acidic food group.

When you eat food, it breaks down to an ash residue that can be neutral, acidic or alkaline. Minerals such as potassium, calcium, magnesium, sodium, zinc, silver, copper and iron produce an alkaline ash; whereas sulfur, phosphorus, chlorine and iodine, which are in meat, coffee, dairy and alcohol, leave an acid ash.

Going alkaline easier than ever with this: Acidic and Alkaline Foods List

tuna is gluten free.

glutinous foods have side effects but a gluten free diet can help

Is tuna gluten free? Yes, tuna is gluten free. Tuna does not contain gluten when unbreaded and unseasoned. Tuna is a type of fish, therefore making it a naturally gluten free food. 

While celiac disease may not be as rampant as many marketing trends lead us to believe, you may have a gluten sensitivity…

Celiac and gluten sensitivity symptoms are similar and may include:

There are hundreds of potential symptoms, many of which are also symptoms of other conditions.

Going gluten-free easier than ever with this: Gluten and Gluten Free Foods List

tuna is a common food allergen: fish.

side effects of common food allergens like milk, wheat, soy, fish, tree nuts, peanuts, eggs and crustaceans

Is tuna a common food allergen? Yes, tuna is a common food allergen: fish. Many people experience allergic reactions to tuna.

A group of the eight major allergenic foods, AKA the Big-8, include:

These foods account for about 90% of all food allergies in the United States.

Severe food allergies can be life threatening. Following ingestion of a food allergen, a person with food allergies can experience a severe, life-threatening allergic reaction called anaphylaxis. 

Persons may still be allergic to and have serious reactions to foods other than the eight foods identified by the law.

Be aware of common dietary restrictions and food allergens with this: The Big 8 Most Common Food Allergens List

tuna is high in mercury.

mercury levels in seafood and fish have dangerous side effects

Is tuna high in mercury? Yes, compared to other kinds of seafood tuna is high in mercury.

Mercury is metal that produces toxic effects to the body. If consumed in high quantities it poisons the kidneys and nervous system. Mercury occurs naturally at low levels in rock, water and soil. However, human activity (most notably the burning of fossil fuels) has dangerously increased mercury levels to be around 450% higher than natural. 

Air pollutants from coal burning factories, for example, can travel around the world into lakes, rivers, and oceans. It is then absorbed and ingested by small aquatic organisms and starts working its way up the food chain.

Large, predatory fish on top of the food chain the highest levels of mercury, namely:

All fish and shellfish contain at least some traces of mercury. Nearly all mercury that we acquire within our bodies comes from eating seafood.

Too much mercury can cause the following symptoms:

The only way to ensure you do not consume mercury is to eliminate seafood from your diet entirely. Fish and crustaceans can be replaced by foods that are high in omega-3 fatty acids and vitamins such as D and B2 (riboflavin). 

Here’s an excellent book for further information on seafood: Bottomfeeder: How to Eat Ethically in a World of Vanishing Seafood by Taras Grescoe

tuna has a high carbon footprint.

carbon footprints of food and food emissions

Does tuna have a high or low carbon footprint? Tuna has a relatively low carbon footprint compared to other foods.

What is the carbon footprint of tuna? It takes around 6.1 CO2e to produce 1 kilogram or 2.2 pounds of canned tuna, a car driving equivalent of 14 miles or 22.5 kilometers.

Food not only has a water footprint but also a carbon footprint, known as CO2e, which stands for carbon dioxide equivalent. Since carbon measurements are a bit more difficult to comprehend, it is common to equate CO2e to the distance which a car drives in miles or kilometers.

When calculating carbon emissions, some factors may include…

There are a number of steps we can take to reduce energy output. According to Oxford Martin School researchers, if the world went vegan, eliminating animal-derived products, it could reduce greenhouse gas emissions by two thirds and avoid climate damages of $1.5 trillion.

But that’s not all!

It’s best to keep the following in mind when grocery shopping:

Find out how much carbon your food emits with this: Carbon Footprints of Foods and Ingredients List

tuna is unsustainable.

side effects of seafood, unsustainable food that pollutes oceans with plastic

Overall, is tuna eco friendly? Is tuna sustainable?

Tuna production is relatively unsustainable.

Whether farmed or wild caught, the seafood industry is environmentally destructive due to its direct impact on decreasing marine populations, polluting waters and habitat destruction.

Wild-caught fish and seafood is destructive due to overfishing (when populations die at a greater rate than they are able to replenish). Degraded ecosystems occur as a result and creates an imbalance that impacts important food chains. Consequently, vulnerable aquatic species like sea turtles and coral suffer. Scientists predict oceans will be fishless by 2048. Such a major loss in biodiversity would be catastrophic, as oceans regulate temperature and contribute to half of our oxygen on Earth.

There’s also an alarming amount of plastic pollution in our oceans. Abandoned and lost fishing gear make up more than 85% of all plastic pollution. Nets, traps and hooks continue to kill marine life. According to Greenpeace, “Abandoned fishing nets kill and injure more than 100,000 whales, dolphins, seals and turtles each year”.

Fish farming, or aquafarming, is not a sustainable alternative. Not only do farmed fish need to be fed fish to eat (perpetuating a never-ending cycle of fishing) but waters become contaminated with antibiotics (to prevent disease that inevitably occurs with overcrowded fish confinements), pesticides, parasites and fish feces. The toxic water then spreads to waterways and oceans, polluting ecosystems and eventually killing off wild fish populations.

All of the aforementioned fishing practices occur in order to meet global demand. The obvious solution for protecting our Earth’s oceans and waterways, marine habitats, ecosystems and wildlife is for consumers to significantly reduce or eliminate their seafood demand entirely.

tuna is not vegan.

seafood and fish is not vegan

Is tuna vegan? No, tuna is not vegan. Tuna is a type of fish, a living marine animal, therefore making it an animal-derived food. A tuna fish must be killed in order to produce tuna. 

Animals of factory farms and the livestock industry are suffering. They live in horrific conditions that often include confinement, physical abuse and unnatural environments…so much so that they need to receive antibiotics to keep from getting ill or spreading disease. They’re also injected with growth hormones to become fatter faster and live short lives, being slaughtered as soon as they finish growing and are killed prematurely, well before their natural lifespan.

Because we cannot see for ourselves how these animals live and what they endure does not mean it isn’t happening. The meat, poultry and dairy industries do everything they can to distance us from knowing how our food comes to be in order to keep us in the dark about what we support each time we buy animal derived products and byproducts.

Go vegan for animals!

It’s the best way to help animals and it’s not as difficult as you may think. Speak for animals with your actions, for they cannot speak at all.

Going vegan is easier than ever, at a glance with this: Vegan and Non Vegan Foods List

tuna has labor issues and human rights concerns.

labor rights, human rights and workers rights issues for the fishing industry

Is tuna a product that has known labor issues?

Yes. There are reports of serious worker mistreatment regarding the seafood industry. Tuna is a product that has human rights concerns.

There are high numbers of trafficked people promised work but then held at sea against their will. Boats filled with trafficked migrants do not dock, sometimes for years on end, keeping slave workers unseen and trapped at sea, continuing the forced labor. Recruiters trick migrants into thinking they must work to pay off their debts, referred to as “debt peonage”. There is little to no compensation for their work which is given for long periods -maybe even years. Seafood caught illegally from slave worker boats gets mixed in with legal, commercial fishing boats in order to remain undetected.

Fishing workers everywhere are at risk of accident, injury, and death. Injuries include cuts, broken bones, lost fingers, hands and limbs, head injuries and electrocutions. Workers get caught in machinery, get thrown overboard and deaths are reported. Boats are in constant motion, decks are slippery and there can be hazardous machinery present.

Fishing industries around the world are responsible for systematic, illegal fishing practices and human rights abuse. Fishing workers are vulnerable to human trafficking and slave labor, especially in countries like Thailand (the third largest seafood exporter in the world), Burma, Indonesia and Fiji. Seafood slavery is a major issue for migrant workers originally from Myanmar, Cambodia, Laos and Vietnam.

We improve lives around the world if we boycott problematic foods that are difficult for human rights authorities to regulate.


Fish, tuna, fresh, yellowfin, raw – FoodData Central – USDA

World Wide Fund for Nature: Overfishing


Healthline nutrition: tuna

Human rights watch: Hidden Chains Rights Abuses and Forced Labor in Thailand’s Fishing Industry

International Labour Office: Caught at sea

NRDC: Mercury Guide

Adriane Marie

As an educator, author and conscious consumer advocate, I study and organize ethical info for you to quickly see how our purchases impact animals, people and the planet. I hope you find this HEALabel knowledge useful and can apply it to your life for personal and societal improvement and empowerment.