Canned tuna is a popular pantry staple due to its ease of use, affordability, and high protein content. However, like other fish, it contains mercury, which, in high levels, can be harmful. Understanding the safe amount of canned tuna you can consume weekly is essential to reap its nutritional benefits while minimizing risks.
Mercury in Tuna and the Risk
Mercury is a naturally occurring element in the earth’s crust and is released into the environment through volcanic activity and human activities like coal burning and industrial processes. Once released, mercury can travel through the atmosphere and eventually settle in bodies of water, like oceans, where it transforms into methylmercury, a toxic organic compound.
Fish, including tuna, absorb mercury, primarily in methylmercury, from the water they swim in and the prey they consume. Over time, mercury accumulates in the flesh of fish, and larger, longer-living predators such as tuna tend to have higher levels of mercury due to bioaccumulation. This process occurs when a fish consumes other organisms that have mercury in their bodies, leading to an accumulation of mercury in the fish’s body over its lifetime.
The concern with mercury stems from its potential health risks when ingested by humans, especially in high amounts.
Here’s how mercury, once ingested, could pose risks:
- Nervous System Damage: Mercury is a neurotoxin that can cross the blood-brain barrier, potentially causing damage to the nervous system. High levels of mercury exposure can lead to tremors, memory problems, and, in severe cases, brain damage.
- Developmental Delays in Children: Developing fetuses, infants, and young children are most at risk from mercury exposure. In children, excessive mercury exposure can interfere with the development of the nervous system, affecting cognitive thinking, memory, attention, language, and fine motor and visual-spatial skills.
- Heart Disease: Some studies suggest that mercury exposure might be associated with an increased risk of cardiovascular diseases in adults. The potential risks include higher chances of heart attacks, coronary heart disease, and other cardiovascular events.
- Other Health Concerns: Mercury exposure could also lead to vision or hearing loss, muscle weakness, lack of coordination, and, in extreme cases, death.
Pregnant and nursing individuals have higher stakes as mercury can pass from the mother to the fetus or newborn, potentially impacting the child’s development.
Given these risks, health organizations and food safety authorities have established guidelines to help individuals make safer seafood choices. The categorization canned tuna into “Best Choices” and “Good Choices” by the FDA, based on mercury content, serves as a guide for consumers to enjoy the nutritional benefits of tuna while minimizing mercury exposure risks.
How Often Should You Eat Canned Tuna?
The safe amount of canned tuna can vary based on individual factors:
- Body Weight and Diet: The safe amount of tuna can be influenced by one’s body weight and overall diet. It’s advised to spread tuna consumption over the week rather than eating it in large amounts at once to minimize mercury exposure.
- Special Populations: Pregnant and nursing women and young children are advised to adhere to more restrictive guidelines due to the potential adverse effects of mercury.
The frequency of canned tuna consumption is subject to various factors, including the type of tuna, the individual’s age, and the sensitivity to mercury, especially in groups like pregnant or nursing individuals and young children.
The Dietary Guidelines for Americans suggests most adults should aim for at least 8 ounces, or 2 servings, of fish per week, encompassing canned tuna within this recommendation. This guideline aims to provide a balanced intake of essential nutrients like omega-3 fatty acids while minimizing mercury exposure.
On the other hand, the Food and Drug Administration (FDA) advises choosing fish varieties lower in mercury, especially for children aged 1-11 and individuals who are pregnant, attempting to become pregnant, or breastfeeding.
The serving sizes are defined differently for adults and children by the FDA: for adults, 4 oz is considered 1 serving, while for children, the serving size varies from 1 oz for ages 1-3, 2 oz for ages 4-7, 3 oz for ages 8-10, and 4 oz for those aged 11 and older.
Canned light tuna, low in mercury, is highlighted as one of the best choices for limiting mercury exposure. Pregnant or breastfeeding individuals can have 2-3 servings of canned light tuna per week. In comparison, children are advised to have 2 servings per week. This aligns with the FDA’s categorization of canned light tuna as a “Best Choice” due to its lower mercury content.
However, white albacore and yellowfin tuna, whether canned, fresh, or frozen, contain slightly more mercury, falling under the “Good Choices” category by the FDA. These tuna varieties are not advised for children. Still, pregnant or breastfeeding individuals can have up to 1 serving per week, allowing for some variety in seafood consumption while minimizing mercury exposure.
Bigeye tuna, often featured in sashimi and sushi, is high in mercury and is not recommended for sensitive groups like pregnant or nursing individuals and children. Additionally, the FDA points out that these groups should avoid raw fish altogether to mitigate the risk of foodborne illnesses.
FDA Recommendations & Guidelines on Canned Tuna Consumption
The U.S. Food and Drug Administration (FDA) has set forth guidelines to ensure the safe consumption of canned tuna, primarily due to its mercury content.
Here are the key takeaways:
- Light Tuna: Adults are advised to limit their consumption to no more than 12 ounces of canned light tuna per week, which equates to about three 5-ounce cans. Light tuna generally has lower mercury levels than other types, making it a safer choice for more frequent consumption.
- Albacore Tuna: Albacore tuna has a higher mercury content, necessitating more restrictive guidelines. Some sources suggest a limit of one average-sized can per week to minimize mercury exposure.
Dietary Guidelines for Americans
The 2020-2025 Dietary Guidelines for Americans emphasize the importance of including seafood in your diet for its nutritional benefits, particularly the omega-3 fatty acids:
- Seafood Consumption: The guidelines recommend a minimum of 8 ounces of seafood per week. Canned tuna is a convenient and affordable way to meet this recommendation, offering a high-protein, low-calorie option rich in essential nutrients.
Light Vs. Albacore Tuna
Understanding the difference between light and Albacore tuna can help in making informed decisions regarding consumption:
- Mercury Content: Light tuna, usually skipjack, has lower mercury levels than Albacore tuna, making it a safer option for more frequent consumption.
- Nutritional Value: Both types offer high protein, essential omega-3 fatty acids, and other vital nutrients, albeit with a variance in mercury content, which impacts the recommended consumption levels.
Frequency of Consumption
The frequency at which canned tuna can be safely consumed varies based on the type of tuna:
- Weekly Frequency: Some sources suggest that light tuna can be eaten up to 12 times per week, aligning with the FDA’s guideline of 12 ounces per week, while the mercury-rich Albacore type should be limited.
Is Canned Tuna Safe For Pregnant Women?
Regarding pregnant and nursing individuals, the FDA has set guidelines emphasizing seafood consumption, including canned tuna, due to its nutritional benefits. Pregnant and breastfeeding individuals are encouraged to consume between 8 to 12 ounces of a variety of seafood per week, opting for those lower in mercury. In terms of serving size, the FDA defines one serving as 4 ounces, suggesting 2 to 3 servings a week from seafood lower in mercury or 1 serving from those with a moderate mercury level.
When it come to the type of tuna, canned light tuna, including skipjack, is classified as a “Best Choice” by the FDA due to its lower mercury content, making it a safer option for more frequent consumption. On the other hand, canned albacore or white tuna falls under “Good Choices,” indicating a higher mercury content and suggesting lesser consumption.
The Mayo Clinic also chimes in on this, recommending a limit of 6 ounces of albacore tuna and tuna steaks per week. Verywell Family provides a more detailed guideline, suggesting up to 12 ounces of canned light tuna and up to 4 ounces of albacore or yellowfin tuna per week for pregnant individuals.
Is Canned Tuna Safe For Children?
For young children, the FDA provides age-specific serving sizes: 1 ounce for ages 1 to 3, 2 ounces for ages 4 to 7, 3 ounces for ages 8 to 10, and 4 ounces for age 11. It’s suggested that children have 2 servings a week from the seafood listed as “Best Choices” by the FDA. Although the exact age to introduce tuna to children is not specified, the mercury content in fish is a crucial factor to consider. Hence, consulting healthcare providers for personalized advice is recommended.
A notable mention is the Safe Catch Elite brand, recognized as the only canned tuna on the market that meets Consumer Reports’ “Low Mercury” criteria, making it a trusted choice for pregnant individuals and children.
Furthermore, the new U.S. Dietary Guidelines emphasize the consumption of seafood, especially those rich in omega-3 fatty acids and lower in mercury, for individuals planning on having children and those pregnant or breastfeeding. This highlights the importance of making wise seafood choices, including canned tuna, to reap the nutritional benefits while minimizing potential health risks associated with mercury exposure.
Canned tuna is a nutritious and convenient choice. Still, moderation and adherence to guidelines are crucial to mitigate the risks associated with mercury exposure. Following the guidelines and recommendations ensures you’re consuming canned tuna safely while enjoying its nutritional benefits.