How Often Is It Too Much to Eat Tuna? Understanding Mercury Risks

December 26, 2025 •

3 min read

According to the FDA, most adults should consume 8 to 12 ounces of seafood per week, but how often is it too much to eat tuna? The answer depends heavily on the specific tuna species, as mercury levels can vary significantly and pose a risk with overconsumption.

Quick Summary

Safe tuna consumption depends on the species, with limits for light/skipjack differing from albacore due to varying mercury levels. Vulnerable groups like pregnant women and children need stricter limits to avoid health risks associated with mercury accumulation.

Key Points

Moderate Your Intake: Most adults should limit tuna, especially high-mercury types, to a few servings per week to avoid mercury accumulation.
Choose Canned Light Tuna: Opt for canned light or skipjack tuna, which have lower mercury levels than albacore and can be consumed more frequently.
Restrict Albacore: Due to higher mercury content, limit canned albacore (white) tuna to no more than one 4-ounce serving per week for most adults.
Vulnerable Populations Need Caution: Pregnant women, breastfeeding women, and young children should adhere to stricter guidelines for tuna, avoiding high-mercury varieties entirely.
Diversify Your Fish Intake: To reap omega-3 benefits without mercury risk, include a variety of low-mercury fish like salmon, sardines, and shrimp in your diet.
Understand Bioaccumulation: Mercury builds up in larger, longer-lived predatory fish like tuna, which explains why they have higher levels than smaller species.

The Benefits and Risks of Tuna Consumption

Tuna is a global dietary staple, prized for its high-quality protein, affordability, and versatility. It is also an excellent source of essential nutrients, including heart-healthy omega-3 fatty acids (DHA and EPA), selenium, and vitamins B12 and D. However, concerns regarding its mercury content have led many to question how much is too much.

Why Mercury is a Concern in Tuna

Mercury, released into the environment from natural events and human activities like industrial pollution, can accumulate in our oceans and waterways. In the water, bacteria convert it into methylmercury, a highly toxic form that builds up in fish tissues. As larger, predatory fish like tuna consume smaller fish, the mercury concentrates in their bodies through a process known as bioaccumulation. This means larger and longer-lived tuna species generally contain higher mercury levels than smaller ones.

Mercury Risk Varies by Tuna Species

Not all tuna are created equal when it comes to mercury. Understanding the differences is crucial for safe consumption.

Canned Light Tuna: Typically made from smaller, faster-growing skipjack or yellowfin tuna. This variety contains the lowest average mercury levels, making it the safest option for more frequent consumption.
Canned Albacore (White) Tuna: This species has higher mercury levels due to its larger size and longer lifespan. The FDA places it in the 'good choices' category, but with stricter limits.
Fresh/Frozen Tuna: Species like yellowfin (ahi) and especially bigeye tuna tend to have significantly higher mercury concentrations than their canned counterparts. Bigeye tuna, often used in sushi and sashimi, is one of the highest mercury fish and is not recommended for vulnerable populations.

Official Guidelines for Safe Tuna Intake

Health organizations provide clear guidelines to help consumers navigate tuna consumption safely. Recommendations vary based on the tuna species and individual health factors.

For the General Adult Population: The FDA advises most adults to eat at least 8 ounces of fish per week, and up to 12 ounces. This can include 2 to 3 servings (8 to 12 ounces total) of canned light tuna weekly. For canned albacore, it's recommended to limit intake to one 4-ounce serving per week.
For Pregnant, Breastfeeding Women, and Young Children: These groups are especially vulnerable to mercury's neurological effects. They should stick to 'best choices' like canned light tuna, consuming 2 to 3 servings per week. Most experts recommend limiting or avoiding albacore and other high-mercury species entirely. Some consumer groups suggest pregnant individuals avoid tuna altogether due to unpredictable spikes in mercury levels found in individual cans.

Mercury Levels and Recommended Consumption by Tuna Type


Tuna Type	Average Mercury (ppm)	General Adult Weekly Recommendation
Canned Light (Skipjack)	0.126	2–3 servings (8–12 oz)
Canned Albacore (White)	0.350	1 serving (4 oz)
Fresh/Frozen Yellowfin (Ahi)	0.354	Limit to one serving or less
Fresh/Frozen Bigeye	0.689	Avoid or consume very rarely

Practical Tips for Safe Tuna Enjoyment

To maximize the health benefits of tuna while minimizing mercury risks, follow these practical strategies:

Diversify your protein sources. Instead of relying solely on tuna, incorporate other low-mercury options like salmon, sardines, and cod.
Read the label. Always check whether you are buying canned light (skipjack) or albacore tuna, as their mercury content and recommended limits differ significantly.
Look for mercury-tested brands. Some brands, like Safe Catch, individually test every fish for mercury, offering a potentially safer option.
Opt for water-packed and low-sodium versions. This is a good general nutritional practice, though water vs. oil does not affect mercury content.

Conclusion: Moderation and Smart Choices are Key

So, how often is it too much to eat tuna? There is no single answer, but making informed choices is crucial. By understanding that different species contain varying levels of mercury and adhering to recommended consumption limits, you can continue to enjoy tuna's nutritional benefits without compromising your health. For most healthy adults, sticking to low-mercury varieties a couple of times a week is a safe and beneficial approach, while pregnant women, young children, and those planning a pregnancy should exercise greater caution and consider alternatives to higher-mercury types. The key is mindful moderation and a balanced diet that includes a variety of protein sources. For more official guidance on fish consumption, you can review the FDA's official advice on eating fish.

Frequently Asked Questions

No, eating canned tuna every day is not recommended for most people due to the risk of mercury accumulation over time. Moderate intake, focusing on low-mercury types, is a safer approach.

Canned light tuna, primarily made from skipjack, is the safest option due to its significantly lower mercury content compared to other varieties like albacore and bigeye.

For most healthy adults, the FDA recommends consuming 2 to 3 servings (8 to 12 ounces) of canned light tuna per week.

Overexposure to mercury can act as a neurotoxin, potentially causing neurological problems such as impaired motor skills, memory loss, tremors, and anxiety.

Mercury enters the ocean through natural and human pollution and is converted to methylmercury by bacteria. Tuna, being predatory fish, accumulate this methylmercury by consuming smaller fish.

Canned tuna, especially the light variety, generally has lower mercury levels than fresh or frozen tuna steaks, which are often from larger species like yellowfin or bigeye.

Pregnant women should limit tuna consumption. They can have 2 to 3 servings of canned light tuna per week but should strictly limit or avoid higher-mercury types like albacore and bigeye.