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K E Y P O I N T S

The Food Standards Agency (FSA) has advised that women who are trying for a baby, are pregnant or are breastfeeding should limit their intake of tuna. The recommended weekly maximum is two medium-sized cans of tuna (with a drained weight of 140g per can), or one tuna steak.

The Food Standards Agency's advice is a precautionary measure, due to concerns about the amount of mercury that could be contained in tuna fish. It applies to women who are trying for a baby, are pregnant or are breastfeeding.

Experts say the advice is unlikely to be too much of a problem for women, because most do not eat more than the weekly maximum.

Tuna is an oily fish and contains omega-3 fatty acids that are beneficial to the mother and baby. Omega-3 fatty acids help a baby's brain and eyes to develop. Other oily fish, such as sardines and salmon, are just as good sources.

Previous advice about pregnant women, infants and children under 16 years old avoiding shark, swordfish and marlin still stands. For more on this advice, please read our earlier news story about oily fish.

Fish is an important component of a healthy, balanced diet. Fish is low in fat and is a good source of protein and other nutrients.

Limit tuna intake when pregnant

Bupa investigative news - 21 February 2003
written by Rachel Newcombe, Bupa health news reporter

Women who are pregnant have been advised to avoid eating certain types of fish because of the amount of mercury contained in them. New recommendations have now widened this advice to include tuna. According to UK Government guidelines, women who are pregnant, breastfeeding or trying for a baby are should limit the amount of tuna they eat each week. High levels of mercury in a woman's diet may have a damaging effect on unborn and breastfed babies.

What were the headlines?

Coverage of the story appeared in all the major newspapers in the UK, and even got a mention in America, gaining headlines such as "Tuna warning", "Pregnant women warned over tuna", "Tuna warning for new mothers", "Fears over tuna health risk to babies" and "Don't eat tuna if you're pregnant".

The reports ranged from detailed analysis of why tuna should be eaten in moderation, to a brief snippet of information about the new guidance. Most reports were informative and balanced, despite headlines filled with mentions of "fear" and "warning". Only one of the headlines - "Don't eat tuna if you're pregnant" - was a touch on the misleading side.

What is the bigger picture?

The UK Government's Food Standards Agency (FSA) issued its advice after it had evaluated an extensive review by the independent Committee on Toxicity (COT) into the possible risks of mercury on unborn and newly born babies.

Experts from COT compared the levels of mercury found in tuna with the World Health Organisation safety guidelines for weekly mercury intake. Although the limit was found to be sufficient for protecting the general population, they were concerned about the safety of babies and felt that maximum levels of tuna consumption should be recommended as a precautionary measure.

As a result, the 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. The full FSA advice is available at: http://www.food.gov.uk/news/newsarchive/tunaadvicenew.

Dr. Andrew Wadge, acting director of food safety at the FSA, said: "It is unlikely that many pregnant or breastfeeding women eat more than the recommended amounts of these fish every week. But for any that currently do, it would be a sensible precaution to change their diets slightly. This will help protect the unborn child and the developing baby."

He added that: "When planning to have a baby and while pregnant or breastfeeding, women do need to take particular care of their health and that of their baby."

The tuna limit adds to previously released FSA advice in May 2002 that pregnant women, infants and children under 16 years old should avoid eating shark, swordfish and marlin due to mercury worries. For more on the this advice, please read Bupa's previous news story about oily fish.

“Although the advice for pregnant women to reduce their tuna intake sounds alarming it's important to realise that the risk seems to be small. To exceed the recommended weekly maximum would require eating more than two medium-sized cans of tuna per week, something most pregnant women won't be doing. Pregnant and breastfeeding women should try to eat a balanced diet, without an excess of any one particular food. With regard to eating fish, the best advice is to reduce tuna intake to less than two medium-sized cans per week, and to avoid eating shark, marlin or swordfish entirely.”

Dr Annabel Bentley,
assistant medical director
Bupa Group

What does this mean?

The reason for concern about high levels of mercury stems from the fact that it can potentially cause harm to a developing nervous system, making unborn and newborn babies particularly vulnerable to its effects.

However, Dr Sarah Schenker, a state registered dietician from the British Nutrition Foundation (BNF), thinks that the tuna restriction is unlikely to be a big problem for the majority of women. "If you're consuming more than two cans of tuna per week, it's quite a lot," she said. Women who fall into that category would be "relying on it heavily and probably excluding other sources of protein and not getting a big enough variety of foods".

Fiona Ford, a nutritionist and spokesperson for the charity Wellbeing, agreed. "It is vitally important that women who are thinking of becoming pregnant or who already are realise that they will need to eat an awful lot of tuna for this to be a problem," she said. "Our concern is for the women who are already pregnant, rather than those who are trying," she added, "as they have not had the benefit of this knowledge."

A spokesperson for Foresight, a charity concerned with pre-conceptual health and nutrition, said the advice reinforces the need for women trying for a baby to take just as much care of their diet as those who are already pregnant.

A C T I O N P O I N T S

Try other oily fish such as sardines, mackerel and salmon and aim for one serving per week if you're pregnant.

Eat within the recommended tuna limits while pregnant, breastfeeding and trying for a baby. Once you've had your baby and aren't breastfeeding, you can increase your consumption again.

Vary your diet to ensure you obtain all the necessary nutrients.

If you're trying for a baby, looking after your diet and health will have a positive effect on conception.

The Food Standards Agency's advice for the general population is to eat two portions of fish per week, one of which should be oily. For more on this advice, please read Bupa's previous news story about oily fish.

What does this mean to me?

If you fall into one of these categories then it's important to be aware of the need to limit your tuna intake, but it certainly doesn't mean that you can't eat tuna at all.

Making sure that you include oily fish in your diet is beneficial - whether you are pregnant or not - because of the omega-3 fatty acids they contain. Omega-3 fatty acids help reduce the risk of heart disease, blood clotting and arthritis. And, says Fiona Ford, omega-3 fatty acids also play a role in the development of a baby's eyes and brain, so eating other oily fish, such as sardines, salmon or mackerel, is still recommended during pregnancy. As a guideline, one serving of an oily fish a week should provide the necessary nutrients.

Other than tuna, there aren't too many food restrictions that pregnant women need to consider. The main things, said a spokesperson for the National Childbirth Trust (NCT), are to avoid soft unpasteurised cheeses, eggs, raw seafood and pate as they can contain bacteria that could harm an unborn baby (such as salmonella, listeria and toxoplasma).

Eating as healthily as you can is great, but according to Dr Schenker it's a common misunderstanding that you should consume a lot more during pregnancy. "The biggest mistake women make is the idea that you should eat for two," she said. "Pregnant women don't really need that many extra calories, as the daily recommendations only go up by 200 calories per day towards the end of pregnancy."

The best way of eating, she suggests, is to "listen to your appetite". Dr Schenker went on: "Don't assume you've suddenly got a whole other person you're eating for. You haven't - you've got a tiny baby. The important thing is to make sure you get all the nutrients you need - variety really is the key to a healthy balanced diet."

Summary

Most women who are pregnant, breastfeeding or trying to conceive do not need to be overly concerned about the new recommendations as they will not be eating more than the recommended maximum. It is important that women do not cut out oily fish from their diet entirely because the omega-3 fatty acids they contain are beneficial both to adult and baby. One serving of oily fish a week should supply enough omega-3 fatty acids without causing any problems.