How Often Can You Eat Tuna?

Tuna is one of the most convenient sources of protein and omega-3 fats in the American diet. It is also one of the most common sources of mercury exposure. For most healthy adults, the Food and Drug Administration advises eating two to three servings of lower-mercury fish each week, and canned light tuna can be part of that. The catch is that “tuna” covers a wide range of species with very different mercury levels, so how often you can safely eat it depends on which type you choose and who is eating it.

How Often Can You Eat Tuna Safely?

For most healthy adults, canned light tuna fits within the general recommendation of two to three servings of fish per week. A serving is about 4 ounces, roughly the size of your palm.

Albacore, often sold as “white” tuna, is a different story. It contains roughly two to three times the mercury of light tuna. The FDA groups albacore with fish that should be eaten once a week at most, and some consumer advocacy groups recommend limiting it further.

Fresh and frozen tuna steaks vary widely depending on the species. Bluefin and bigeye carry the highest mercury levels and appear on the FDA’s “choices to avoid” list entirely. Yellowfin and skipjack are lower. If you don’t know the species, you can’t reliably judge the risk.

People who are pregnant, may become pregnant, are breastfeeding, or are young children need stricter limits. The FDA and EPA advise these groups to eat 8 to 12 ounces of fish per week from the “best choices” list and to limit albacore to no more than 4 ounces per week. Canned light tuna is considered a best choice for this group.

Why Does Mercury in Tuna Matter?

Mercury occurs naturally in the environment and is also released by industrial activity. Bacteria in water and sediment convert it into methylmercury, which is the form that accumulates in fish.

Methylmercury binds tightly to proteins in fish muscle. That means you cannot remove it by draining the can, rinsing the fish, or cooking it. The mercury is in the tissue itself.

In the human body, methylmercury is absorbed efficiently from the gut and distributed throughout the body, including to the brain. It is cleared slowly. The half-life in blood is roughly 45 to 70 days, which means repeated meals can cause levels to build up over time rather than clearing quickly between servings.

The main concern is neurotoxicity. In adults, the nervous system effects of low-level methylmercury exposure have been studied for decades, and the evidence for harm at ordinary dietary levels is not clear-cut. The developing brain is more vulnerable. That is why pregnancy and early childhood drive most of the official guidance.

Which Tuna Has the Least Mercury?

Skipjack tuna, which is what most canned light tuna contains, has the lowest mercury of the common commercial species. That is why canned light tuna is treated differently from albacore and from fresh tuna steaks in federal guidance.

Here is how the major types compare in general terms:

• Canned light tuna — usually skipjack, sometimes yellowfin. Lowest mercury among canned options.
• Canned albacore (white) tuna — higher mercury, roughly two to three times light tuna.
• Yellowfin and skipjack steaks — moderate mercury.
• Bigeye tuna — high mercury, commonly used in sushi.
• Bluefin tuna — highest mercury, on the FDA’s avoid list.

One practical complication: a can labeled “light” is not a guarantee of a single species. It can be a blend. That is one reason the FDA guidance is built around categories rather than exact numbers.

If you eat sushi, tuna nigiri or sashimi is often bigeye or yellowfin. Portion sizes at restaurants tend to be larger than a standard 4-ounce serving, which matters if you eat it often.

How Much Tuna Is Too Much?

There is no single number that applies to everyone. The safe amount depends on your body weight, the species you are eating, and whether you are pregnant or feeding a young child.

What the guidance does give you is a structure. For healthy adults, two to three servings of fish per week from the best-choices list is the general target. If all of those servings are albacore, you are getting considerably more mercury than if they are light tuna.

A reasonable way to think about it: eating tuna daily for months is where the accumulation concern becomes real, especially if it is albacore or fresh tuna. Eating it a few times a week from lower-mercury options is consistent with what federal agencies describe as safe for most adults.

There is a separate issue people often miss. Fish is genuinely good for you. The omega-3 fats in fish are linked to heart health, and the official guidance is designed to encourage fish consumption, not discourage it. The point of the mercury limits is to steer you toward the right fish, not away from fish altogether. Replacing tuna with a burger is not an improvement.

Who Needs to Be More Careful With Tuna?

Three groups need to follow stricter limits.

People who are pregnant or may become pregnant, and people who are breastfeeding. The FDA and EPA recommend 8 to 12 ounces per week of fish from the best-choices list, and no more than 4 ounces of albacore per week. Canned light tuna is on the best-choices list. Bigeye, bluefin, and other high-mercury fish should be avoided entirely.

Young children. Children should eat smaller portions, and the same species rules apply. A common approach is to serve one to two small servings per week from the best-choices list. Because children are smaller and their brains are still developing, the margin for error is narrower.

Anyone eating a lot of tuna for muscle gain. Canned tuna is a staple in high-protein diets, and some people eat it most days. That pattern can push mercury intake well above what occasional eaters get. If tuna is a daily food for you, rotating in lower-mercury protein sources is worth considering.

No clinical guidelines exist for setting a precise mercury intake limit for every individual, because the relationship between dietary mercury and health outcomes in adults is still not fully defined. The federal guidance is built on protecting the most vulnerable groups, which is a deliberately cautious approach.

Does Cooking or Draining Tuna Remove Mercury?

No. Mercury cannot be cooked out, drained away, or rinsed off. It is chemically bound to the protein in the fish, so it stays with the meat through every preparation method.

This is a common misconception, and it leads people to think they can eat more tuna if they prepare it a certain way. They can’t. The only variables that change your exposure are the species, the portion size, and how often you eat it.

What you can control is the type. Choosing skipjack-based light tuna over albacore lowers your mercury intake for the same number of meals. Choosing a smaller portion does the same. Choosing a different fish entirely some nights does more.