Why all the food restrictions during pregnancy?

Posted by on Sep 25, 2012 in Blog, Latest News, Nutrition Tips | 3 Comments
Why all the food restrictions during pregnancy?

Ok, I admit, I have a vested interest in this topic. Why? Well, I’m 6 months pregnant and to be honest I miss feta on my salads and sandwiches. I crave ricotta smeared over sourdough toast with a drizzle of honey, long for some silky raw salmon and tuna sashimi, and pine after a soft-boiled egg with my salad. Why am I denying myself such simple culinary pleasures? Because according to the NSW Health Authority and other health advisory services, uncooked feta and ricotta, raw fish, and runny egg yolks are on the no-go list for pregnant women. So too is soft serve ice-cream, uncooked sprouts, pre-prepared salads, delicatessen meats that are not reheated/cooked, high mercury fish, unwashed fruits and veggies and more. (For the full list of what foods are recommended to avoid during pregnancy – click here).

I didn’t mind so much at first. Although perhaps that had something to do with feeling seasick all day and only craving plain carbohydrate foods – rice cracker or baked potato anyone? But as time has marched on and I’ve felt a whole lot better, slowly I have started to miss these simple food pleasures. So, I thought I’d have a closer look into why these foods are off the menu.

The main risks being targeted by the above restrictions are risk of infection with Listeria, Salmonella, Toxoplasmosis and contamination with mercury. (Note that alcohol, whilst not discussed in this article, is also recommended to be avoided during pregnancy as excessive consumption is associated with Foetal Alcohol Syndrome). During pregnancy, women are considered to be in an immunocompromised state, that is, our immune systems just are not performing they way they usually do, and therefore whilst the above infections  (Listeria, Salmonella and Toxoplasmosis) do not usually have significant repercussions for healthy adults, in pregnant women the effects can be severe for the unborn child.

 

Listeria:

Listeria Monocytogenes is a foodborne pathogen (something that creates disease) that affects humans. Infection in pregnant women and their babies can have devastating effects such as foetal abortion, stillbirth, or premature delivery of an infected infant [1]. If we look at the relative risk of pregnant women being infected compared with a non-pregnant healthy adult, the risk is 39 times higher [2].Early infection in mothers is sometimes difficult to pinpoint as being related to Listeria as it may present as non-specific flu-like symptoms [1] and sometimes as diarrhoea, nausea or tummy cramps [2]. There are generally less than 10 cases of Listeria diagnosed in pregnant women in Australia per year, so the risk is very small and it is considered a rare disease [2].  However, given that infants born with this infection can develop meningitis and sepsis (a very dangerous conditions that require immediate medical treatment) and that the overall mortality rate of infected fetus’s is 50% [1], I can understand why health authorities take such a strict stance to help avoid contamination.

High-risk foods for Listeria include:

  • Cold processed meats, cold cooked chicken
  • Raw seafood (including smoked salmon and trout, live oysters and mussels)
  • Soft & semi-soft cheeses (e.g. brie, camembert, blue, stilton, ricotta – these can be eaten if cooked and consumed when hot). Feta when bought packaged, not from the deli counter, is lower risk due to high salt content that slowly kills the bacteria but still has a higher risk than hard cheeses as the bacteria can survive for 90 days from packaging).
  • Unpasteurized dairy products
  • Pre-prepared salads & sandwiches
  • Soft serve ice cream
  • Pate
  • Leftovers older than 1 day [1-4]

Salmonella:

Salmonella is a common cause of food-borne illness. It is commonly associated with symptoms such as nausea, vomiting, diarrhea, stomach cramps, fever and headache. In pregnancy, there is a very small chance that Salmonella infection can result in miscarriage and therefore it is recommended that foods at high risk of Salmonella contamination be avoided. Given that I don’t fancy having a bout of gastro at any time, let alone now, I am pretty happy to keep avoiding the following foods for a little bit longer!

High-risk foods include:

  • Raw eggs (including runny yolks)
  • Undercooked meat and chicken
  • Sprouts (all kinds!) unless well-cooked [3]

Toxoplasmosis:

Toxoplasmosis is caused by a parasite, Toxoplasma gondii. Whilst infection in pregnant women is rare, when the infection crosses the placenta (in 1/3 of cases) the effects can be severe including brain damage, hearing problems and blindness to the infant [3, 5]. The main infection sources are cat faeces, soil that is contaminated and contact with contaminated raw meat. The suggestions for minimizing the risk of toxoplasmosis infection are not too onerous and are pretty easy to stick to. Recommendations centre on avoiding changing the cat’s litter tray when pregnant, using gardening gloves and washing hands thoroughly after gardening, ensuring fruits and vegetables are washed clean of any residual soil before eating and avoiding undercooked meat [3, 5].

Mercury:

Mercury can occur in high levels in some fish. The effects of mercury contamination affect an unborn babies nervous system and has been associated with developmental delays in childhood. Fish that are at risk include those that are bottom-dwelling, predatory (eat other fish) and are large. Victoria’s Better Health Channel and the NSW Food Authority identify the following fish species as having higher risk of mercury contamination:

  • Shark (flake)
  • Ray
  • Swordfish
  • Marlin
  • Catfish
  • Barramundi
  • Gemfish
  • Orange Roughy (deep sea perch)
  • Ling
  • Southern Bluefin Tuna [3, 6]

The NSW Food Authority recommends limiting intake of high mercury fish during pregnancy to one serve per fortnight for flake, swordfish and marlin (and not including any other fish that fortnight), and to one serve per week for catfish and orange roughy (and not including any other fish that week).

Fish is a highly nutritious food, containing essential omega 3 fatty acids, protein and other minerals and therefore it is a good idea to include 2-3 serves (150 g) of fish not listed above each week to support a healthy foetus. Download a pocket guide to the above recommendations here.

Are all these restrictions going overboard?

Some have argued that this strict approach is not necessary [7, 8]. Are all these extra rules and restrictions simply adding to parents-to-be’s worry and stress levels for their unborn child?

In France, where it is common to consume soft and raw cheeses as part of the traditional diet, I have often heard that they are not advised to avoid these foods. However, they actually DO have recommendations to avoid soft cheeses during pregnancy although I cannot be certain how strictly this is followed in the population. In Japan where the consumption of raw fish is also a feature of their national cuisine, a Japanese friend has told me that, apart from avoiding high mercury fish, there are no restrictions placed on the consumption of raw fish during pregnancy and that it is actually looked upon favourably due to the good nutrient profile. With raw fish being part of the national cuisine, it could be assumed that the handling and quality of the fish is likely to consistently be safer when frequenting higher quality establishments and hence the risk posed by eating raw fish may be less than in countries were raw fish intake is less common.

So what to do?

Ultimately, it is a personal decision. Looking at all of the information above, it does seem that while the risks are relatively low here in Australia, they do exist. What you decide to avoid or include really depends on your own risk profile. For me, whilst I’ve stuck to a lot of the NSW Food Authority’s recommendations, I’ve also snuck the odd bit of feta cheese here and there when a new packet has been opened in front of me, I’ve had a runny egg or two when I was sure of the quality, and have eaten a pre-prepared sandwich or two when the only other option was starvation (although I did make them toast it well!)

For you – I suggest that you do what feels right based on your own food culture, research and preferred risk level. If you do slip up whilst getting the hang of these new food restrictions and accidentally eat something on the no-go list (as I did a few times early on) try not to fret, go easy on yourself and chalk it up to a learning experience.

 

References

1.         Schlech, W.F. and D. Acheson, Foodborne Listeriosis. Clinical Infectious Diseases, 2000. 31(3): p. 770-775.

2.         Food Standards Australia. Listeria and Food: Commonly asked questions. 2005 September 13, 2012 [cited 2012 September 13]; Available from: http://www.foodstandards.gov.au/scienceandeducation/factsheets/factsheets2005/listeriacommonlyaske3115.cfm.

3.         NSW Food Authority. Pregnancy and Food Safety. 2012 March 21, 2012 [cited 2012 September 13]; Available from: http://www.foodauthority.nsw.gov.au/consumers/life-events-and-food/pregnancy/.

4.         Jackson, K.A., M. Iwamoto, and D. Swerdlow, Pregnancy-associated listeriosis. Epidemiology and Infection, 2010. 138(10): p. 1503-9.

5.         Infectious Diseases, E.a.S. Toxoplasmosis. 2007 February 10, 2007 [cited 2012 September 13]; Available from: http://ideas.health.vic.gov.au/bluebook/toxoplasmosis.asp.

6.         Better Health Channel. Mercury in fish. 2012 July 31, 2012 [cited 2012 September 13]; Available from: http://www.betterhealth.vic.gov.au/bhcv2/bhcarticles.nsf/pages/Mercury_in_fish.

7.         AAP, Pregnancy Diet Overkill, in The Sydney Morning Herald2011, Fairfax Media: Sydney.

8.         Shaw, S. Chicken of the sea. New York Times, 2010.  New York: The New York Times Company. [cited July 15, 2007]. Available from: http://www.nytimes.com/2007/07/15/opinion/15shaw.html?emc=th&_r=0.

 


 

This article also appears on Surfsister – check it out.

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