Consider not giving your cat tinned tuna to prevent poisoning and to support conservation

The latest news is: “Mercury found in tins of tuna described as ‘colossal risk to public health’ ” (Foodwatch France which was behind the investigation). Why do tuna have such high levels of mercury in them? And are there good reasons other than ingesting poison for no longer buying tuna in supermarkets? The following information comes from AI.

Out of the 150 tins tested in Britain, France, Italy, Spain and Germany, 148 were found to contain mercury, and more than half exceeded the 1mg/kg limit in UK and EU law. One tin bought in Paris had a record level of 3.9 mg/kg. – Metro newspaper

Tuna have high levels of mercury because of a combination of factors that involve the way mercury moves through the environment and accumulates in organisms. Here’s how it works:

1. Mercury Pollution in the Ocean

• Human Activities: The primary source of mercury in oceans is human activities, like coal burning, mining, and industrial waste, which release mercury into the atmosphere. Once in the atmosphere, it can travel long distances before settling in bodies of water.
• Conversion to Methylmercury: In the water, mercury transforms into methylmercury—a more toxic, organic form of mercury—due to microbial activity.

2. Bioaccumulation in the Food Chain

• Mercury Builds Up in Small Organisms: Plankton and small fish in mercury-contaminated waters absorb methylmercury, and it binds to their tissues.
• Tuna Eat Contaminated Fish: Tuna are large predatory fish, and they eat many smaller fish that have already accumulated mercury in their bodies. Because of this, the mercury concentrations increase as it moves up the food chain, a process known as biomagnification.

3. Long Lifespan and High Position in the Food Chain

• Tuna have long lifespans and are high on the food chain, giving them more time to accumulate mercury from all the fish they eat throughout their lives. This results in significantly higher mercury levels in tuna compared to smaller, shorter-lived fish.

Health Risks of Mercury in Tuna

• Methylmercury is toxic to the human nervous system and poses risks to fetal development, brain function, and overall health, making mercury-contaminated tuna a public health concern. Pregnant women, children, and those with high fish consumption are particularly at risk.

These factors combine to make certain tuna varieties, especially larger species like albacore and bluefin, particularly high in mercury.

Out of the 150 tins tested in Britain, France, Italy, Spain and Germany, 148 were found to contain mercury, and more than half exceeded the 1mg/kg limit in UK and EU law. Is tinned tuna unsafe period, both for cats and people?

The discovery that a significant portion of tinned tuna exceeds mercury limits does raise concerns, especially if consumed frequently or in large quantities, but it doesn’t necessarily mean that all tinned tuna is unsafe. Here’s a closer look at the situation for both humans and pets:

1. Human Health Risks from Tinned Tuna

• Risk from Accumulated Exposure: The danger lies in the accumulation of mercury over time. Occasional consumption is generally considered safe, but frequent, high-quantity consumption can lead to mercury buildup in the body, increasing the risk of mercury poisoning. This can affect brain function, the nervous system, and, especially, fetal development in pregnant women.
• Tuna Type Matters: Smaller species of tuna, such as skipjack, which is commonly used in canned light tuna, generally contain less mercury than larger species like albacore and bluefin. Opting for canned light tuna over white (albacore) tuna may reduce mercury exposure.
• Serving Size and Frequency: Many health authorities suggest limiting consumption. For example, the U.S. FDA advises adults to eat no more than one serving (around 4 ounces) of albacore tuna per week, but allows 2-3 servings of canned light tuna, which tends to be lower in mercury.

2. Tinned Tuna for Cats

• Sensitivity to Mercury: Cats are more sensitive to toxins like mercury due to their smaller body size and lower capacity to metabolize toxins.
• Occasional Treats vs. Regular Feeding: An occasional bit of tuna as a treat is likely safe for most cats. However, using tinned tuna as a regular part of a cat’s diet can lead to health issues, especially if it exceeds safety limits. Chronic mercury exposure in cats can lead to symptoms like loss of coordination, behavioral changes, and other neurological symptoms.
• Nutritional Deficiencies: Tuna also lacks key nutrients cats need, like taurine, and has a high sodium content. Regular feeding of tuna without supplementation can lead to nutritional imbalances in cats.

Alternatives and Best Practices

• Check Tuna Variety and Source: Opting for brands that use skipjack tuna, or those specifically labeled as low in mercury, can reduce exposure. Also, some companies conduct testing to ensure compliance with mercury limits.
• Moderation and Variety: Whether for yourself or your pet, limiting tuna intake and including a variety of low-mercury fish or other proteins is a safer approach.

Bottom Line

Tinned tuna, when eaten occasionally and in moderate amounts, can still be safe for most people and pets. But due to variable mercury levels, it’s wise to follow recommended guidelines, especially for vulnerable groups like pregnant women, children, and pets.

But why eat the stuff and allows cats to eat it when it is essentially poisonous? There are alternatives.

You’re absolutely right: given the health risks associated with mercury, especially in foods like tuna, many people choose to avoid it entirely or opt for safer alternatives. Here are some reasons why it’s often still consumed, as well as some compelling alternatives:

Why People and Pets Still Eat Tuna

1. Tradition and Habit: Tuna has long been a dietary staple, especially in canned form, because it’s convenient, affordable, and widely available.
2. Nutritional Value: Tuna is rich in protein, omega-3 fatty acids, and vitamins like B12 and D. These nutrients are highly beneficial for heart health, brain function, and overall well-being, which is why people often see tuna as a health food—despite the mercury risks.
3. Lack of Awareness: Some consumers aren’t fully aware of the potential dangers associated with mercury in tuna, and messaging about it can be inconsistent across health organizations and countries.
4. Cat Food Ingredient: Cats find the taste of tuna irresistible, and it’s often marketed as a treat food for them. However, it’s typically safer for cats to consume specially formulated foods that are balanced for their dietary needs and free from mercury concerns.

Safer Alternatives to Tuna

For both humans and cats, there are excellent, safer alternatives that provide similar nutritional benefits without the mercury risk:

For Humans

• Other Fish: Smaller fish like salmon, sardines, anchovies, and trout are generally low in mercury and high in omega-3s. Sardines, for example, have very low mercury levels and pack a powerful nutritional punch.
• Plant-Based Omega-3 Sources: Flaxseeds, chia seeds, and walnuts provide alpha-linolenic acid (ALA), an omega-3 fatty acid. While not as potent as fish-based omega-3s, they are beneficial and can supplement other sources.
• Fish Oil Supplements: If omega-3s are the goal, fish oil or algae oil supplements provide them without the mercury risk. Algae-based supplements are particularly appealing as they’re plant-derived and safe for people on vegetarian or vegan diets.
• Other Protein Sources: Eggs, beans, lentils, lean meats, and plant-based protein sources offer nutritional diversity without mercury concerns.

For Cats

• Commercially Formulated Cat Foods: Quality cat foods are balanced to meet a cat’s dietary needs and come in a wide variety of flavors, so you can avoid tuna-based products.
• Other Fish-Based Cat Foods: Salmon and whitefish varieties are typically lower in mercury than tuna and are available in cat-safe formulations.
• Animal-Based Protein Treats: Freeze-dried chicken or liver treats are popular with cats and provide nutrients without any risk of mercury exposure.
• DIY Cat Treats: Small portions of cooked poultry, shrimp, or salmon (prepared without seasoning) can be safe, nutritious treats without the risk of heavy metals.

Bottom Line

While tuna is nutritionally rich, the risks associated with mercury, especially when safer options exist, make it a questionable choice for regular consumption. Opting for alternative protein sources for both humans and pets is often the healthier, safer choice—helping avoid mercury toxicity altogether.

There is another reason for not eating tuna: conservation. Tuna are overfished and becoming endangered.

Absolutely, tuna overfishing is a significant and growing concern globally, both for environmental reasons and for the health of ocean ecosystems. Overfishing has driven several tuna species, especially the larger, more commercially valuable ones like bluefin tuna, toward endangered status. Here’s how conservation issues further justify reducing or avoiding tuna consumption:

1. Overfishing and Species Decline

• Population Decline: Popular tuna species, especially bluefin, yellowfin, and bigeye, are heavily overfished. For example, Atlantic bluefin tuna populations have dropped dramatically, with some estimates suggesting a decline of over 80% since the 1970s.
• Endangered Status: Atlantic bluefin tuna is listed as endangered by the International Union for Conservation of Nature (IUCN), and other species are classified as vulnerable or near threatened. Continued overfishing pushes these species closer to extinction.

2. Ecological Impact of Overfishing

• Disruption of Marine Ecosystems: Tuna are apex predators, playing a crucial role in maintaining balance within marine ecosystems. Removing large numbers of tuna upsets the food chain, affecting everything from small fish populations to marine plants.
• Bycatch and Habitat Destruction: Tuna fishing methods, such as longlining and purse seining, often result in bycatch, where other marine life—like dolphins, sharks, and seabirds—are unintentionally caught and killed. Additionally, some fishing practices damage coral reefs and ocean habitats critical to other species.

3. Sustainability Challenges in Tuna Fishing

• Difficulty of Regulating Tuna Fisheries: Tuna are migratory and cross international waters, which makes sustainable management challenging. Despite international agreements, illegal, unreported, and unregulated (IUU) fishing is rampant in the tuna industry.
• Questionable “Sustainable” Labels: Even “sustainable” tuna products are sometimes controversial. Certifications like the Marine Stewardship Council (MSC) label can still allow methods with significant environmental impacts, such as longlining. As a result, not all “sustainably labeled” tuna are actually as eco-friendly as they claim.

4. Alternative, Sustainable Seafood Choices

• Choosing Smaller, Abundant Fish: Smaller, fast-reproducing fish like sardines, anchovies, and mackerel are generally more sustainable choices than tuna. These fish not only have lower mercury levels but also recover from fishing pressure more quickly.
• Aquaculture (Fish Farming): Some seafood, such as farmed mussels, oysters, and certain types of farmed fish, have a much lower environmental impact than wild-caught tuna and are more sustainable options.

5. Plant-Based and Lab-Grown Alternatives

• Plant-Based “Seafood” Options: Increasingly, plant-based alternatives are available for consumers who enjoy the taste of tuna but want to avoid the environmental and health downsides. Companies are developing realistic, nutritious tuna alternatives made from legumes, algae, and other plant sources.
• Lab-Grown Fish: Cell-based or lab-grown seafood is an emerging field with the potential to provide genuine fish products without requiring the capture of wild populations. Though still in early stages, lab-grown tuna could eventually offer an eco-friendly, ethical alternative to conventional tuna.

Bottom Line

Reducing or eliminating tuna consumption supports both public health and ocean conservation efforts. Choosing sustainable seafood, or opting for plant-based or lab-grown alternatives, can reduce demand on endangered tuna populations and help protect marine ecosystems for future generations.

Bottom line from me: stop buying tinned tuna. I did years ago. Some cat caregivers often feed their cat tinned tuna as a treat but it is not based on what I have just said. My advise is to find an alternative treat. There are many.

What are the symptoms of mercury poisoning?

Mercury poisoning occurs when mercury accumulates in the body, leading to a variety of symptoms that can impact physical and mental health. The symptoms vary depending on the type of mercury (methylmercury, elemental mercury, or inorganic mercury), the level of exposure, and whether the exposure is acute (short-term, high exposure) or chronic (long-term, lower-level exposure). Here’s an overview:

1. Neurological and Cognitive Symptoms

• Memory Loss and Mental Fog: Difficulty remembering things or feeling mentally “foggy.”
• Mood Changes: Depression, irritability, or anxiety.
• Tremors and Muscle Weakness: Tremors in hands, muscle twitching, and general muscle weakness.
• Numbness and Tingling: Especially in hands, feet, or around the mouth, due to nerve damage.
• Loss of Coordination and Balance: Poor coordination, difficulty walking, and balance issues.
• Peripheral Vision Impairment: Mercury poisoning can reduce field of vision, known as “tunnel vision.”

2. Physical Symptoms

• Fatigue and Weakness: General weakness and a constant feeling of fatigue.
• Headaches: Frequent or severe headaches.
• Digestive Problems: Nausea, vomiting, diarrhea, or abdominal pain, particularly with acute exposure.
• Metallic Taste: Many people experience a persistent metallic taste in their mouth.
• Skin Rashes and Discoloration: Peeling or redness on hands, feet, or other skin areas; sometimes, the skin takes on a bluish or greyish tint.

3. Cardiovascular Symptoms

• Increased Heart Rate or Blood Pressure Issues: Chronic mercury exposure can contribute to elevated blood pressure and arrhythmias.
• Poor Circulation: May lead to symptoms like cold extremities or numbness in the limbs.

4. Symptoms in Children and Developing Fetuses

Children and unborn babies are especially vulnerable to mercury poisoning, as it can interfere with brain and nervous system development.

• Developmental Delays: Cognitive and motor delays in infants and young children, which can affect learning, speech, and physical skills.
• Reduced IQ and Learning Disabilities: Children exposed to mercury in utero may experience lasting impacts on intellectual development.
• Sensory Problems: Hearing and visual impairments are also potential symptoms in children affected by mercury exposure.

5. Acute Mercury Poisoning (High, Short-Term Exposure)

For those exposed to high levels of mercury in a short period (often through inhalation in industrial settings or chemical spills), symptoms may be severe and appear rapidly:

• Difficulty Breathing: Coughing, shortness of breath, and chest pain.
• Kidney Damage: Acute kidney issues may develop, leading to protein in the urine, swelling, and changes in urine output.
• Severe Gastrointestinal Issues: Nausea, vomiting, and intense abdominal pain.

Seeking Help and Treatment

If mercury poisoning is suspected, immediate medical attention is critical. Treatment options may include:

• Chelation Therapy: Using medications to bind with mercury in the bloodstream and aid in its removal.
• Supportive Care: For symptoms like tremors or neurological issues, physical therapy or other supportive treatments may help.
• Dietary and Lifestyle Changes: Reducing further exposure to mercury by avoiding high-mercury foods, such as certain fish, and improving overall diet and nutrition.

Early intervention can help mitigate some of the symptoms and prevent further damage, but because mercury poisoning affects the nervous system, recovery may take time and isn’t always complete, particularly in severe cases.

What are the initial, early symptoms?

The early symptoms of mercury poisoning can be subtle and easy to overlook, as they often resemble other health issues. Here are some of the initial signs that may indicate mercury exposure:

1. Neurological Symptoms

• Tingling and Numbness: This often begins in the hands, feet, or around the mouth due to nerve irritation.
• Mood Changes: Unexplained irritability, anxiety, or mood swings can be an early indicator.
• Memory and Concentration Issues: Subtle memory lapses, difficulty focusing, and mental fogginess may appear.

2. Physical Symptoms

• Metallic Taste in the Mouth: A persistent metallic taste is often reported early on, especially in cases of high exposure.
• Fatigue and Weakness: Feeling tired, weak, or unmotivated, even with adequate rest, may be a sign of early mercury exposure.
• Headaches: Frequent, unexplained headaches can be an early sign, particularly if they appear alongside other symptoms.

3. Digestive Symptoms

• Nausea or Upset Stomach: Stomach discomfort, nausea, or mild abdominal pain can develop early, especially in cases of dietary mercury exposure (e.g., from fish).
• Loss of Appetite: A decreased desire to eat may also accompany early symptoms.

4. Sensory Changes

• Vision Changes: Mild visual disturbances, such as blurriness or reduced peripheral vision, can begin early on.
• Sensitivity to Light and Sound: Increased sensitivity to light or loud sounds may also indicate early nervous system involvement.

When to Seek Help

Early symptoms may be subtle, but if you notice a combination of these signs, especially with known mercury exposure (e.g., regular consumption of high-mercury fish), it’s wise to consult a healthcare professional. Early intervention can help prevent progression to more severe symptoms.