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Hot topic - How much fish can we eat safely?

30 June 2004 - written by BUPA's Health Information Team

Men and women should eat at least two portions of fish a week - one of which should be oily.

Eating fish has many health benefits, such as reducing the risk of heart disease. But there are also some potential health risks. Because of this, the UK Food Standards Agency has recommended that men eat no more than four portions of oily fish per week and women and children no more than two.¹

Below we look at the issue in more depth.

How much fish should I eat?

Everyone should eat at least two portions of fish per week (one of which should be oily) because all fish has many health benefits.¹

Why is fish good for you?

Fish is a good source of protein, it contains lots of vitamins and minerals, and it is low in saturated fat. It contains omega-3 fatty acids, a type of polyunsaturated fatty acid that helps reduce the risk of heart disease. All fish contain these oils, but oily fish contain much more of these oils than white (non-oily) fish.¹

Omega-3 fatty acids are also needed for the development of a baby's brain and spinal cord.¹

Fish with edible bones, such as sardines, pilchards and tinned salmon, also contain calcium phosphorus and fluoride. Calcium is needed for strong teeth and bones, phosphorus is essential for many body functions, and fluoride is needed for strong teeth.^1,2

Other vitamins and minerals found in oily fish include vitamins A, which is needed for vision in dim light, as well as for healthy skin, and vitamin D, which is needed for healthy bones. Fish is also a good source of selenium, which helps protect cells from damage by acting as an antioxidant.^1,2

Why is oily fish especially good for you?

Oily fish is particularly good for you because it contains more omega-3 fatty acids. Also, when you eat oily fish you are more likely to eat bones as well as flesh as the bones are often soft and easily chewable, providing calcium, fluoride and phosphorus.¹

How much oily fish should I eat?

Girls and women who might have a child one day, and women who are pregnant or breastfeeding, should always eat one portion of oily fish a week. But the UK Food Standards Agency recommends that they should not eat any more than two portions.¹

Men and boys, and women who will not become pregnant, should also eat at least one portion of oily fish per week. The UK Food Standards Agency say they can eat up to four portions per week.¹

There are no known health risks associated with white fish, so you can eat as many portions per week as you like.

What counts as oily fish?

Oily fish and white (non-oily) fish³
Oily fish include:	White or non-oily fish include:
salmon mackerel fresh tuna (not tinned) trout sardines pilchards anchovies sprats whitebait herring kipper swordfish eel carp bloater swordfish	cod plaice tinned tuna haddock lemon sole whiting halibut skate red snapper dover sole hake red and grey mullet sea bass monkfish sea bream turbot shark marlin

What is a portion of fish?

A portion is 140g (for example a medium-sized can of fish), cooked any way you like.¹ Try easy, low-fat cooking methods like baking, steaming or grilling.

Does tinned fish count as oily fish?

Fresh tuna counts as oily fish, but tinned tuna does not. This is because the canning process removes much of the omega-3 oil, reducing it to the level of white (non-oily) fish. However, tinned tuna does count as a fish portion, just not an oily fish portion.¹

Other tinned oily fish, such as sardines, pilchards and anchovies do count as oily fish - you just need to make sure you eat a full portion (140g).¹

Does smoked oily fish count as oily fish?

Smoked oily fish still counts towards your oily fish, but eating large amounts of smoked foods may slightly increase the risk of some types of cancer, so it is best to eat these only in moderation.⁶

Why should we limit the amount of oily fish we eat?

Oily fish can contain harmful chemicals, such as dioxins and PCBs.¹

Dioxins are a by-product of certain industrial processes and household fires. They are found throughout the environment, and can sometimes be found in oily fish.⁴

PCBs (polychlorinated biphenyls) are a pollutant used mainly in the production of electrical equipment. They are no longer permitted in the UK, but may still be present in the environment, including fish.⁴

Dioxins and PCBs are more concentrated in fatty food, such as fish oils.⁴

Dioxins and PCBs do not have an immediate effect on health, but higher than recommended levels in the diet over a long period of time are thought to increase the risk of cancer.⁵

Should pregnant women eat oily fish?

Yes, the omega-3 oils help the brain and spinal cord develop in the growing fetus and the baby after birth.1 But women who are pregnant or breastfeeding should not eat more than two oily fish portions per week.¹

Pregnant and breastfeeding women have also been advised by the UK Food Standards Agency (FSA) to avoid eating shark, marlin and swordfish because of the possible high levels of mercury.¹

In addition FSA recommends that women who are pregnant, breastfeeding or trying to conceive should eat no more than two medium sized cans with a drained weight of 140g per can, or one fresh tuna steak, per week. This is equivalent to about six rounds of tuna sandwiches or three tuna salads. For more information, please see our news article: Limit tuna intake when pregnant.