Expecting mothers who consume seafood one to three times per week are less likely to experience high levels of anxiety symptoms according to a new study published in PLoS One.

What’s so bad about anxiety during pregnancy?

While it is normal to be a little bit stressed with a baby on the way, excessive anxiety has been repeatedly linked to:

  • Low birth weight and premature birth — both have long term health consequences;
  • Adverse effects on infant neurodevelopment, including stress regulation;
  • Higher risk of emotional disorders later in life;
  • Increased vulnerability to ADHD in childhood;
  • Language delay and suboptimal motor skills;
  • Epigenetic changes in the immune system predisposing the baby to asthma and allergies.

Study details

The researchers asked the 9,530 women who enrolled to fill in a questionnaire assessing their diets and anxiety levels at the 32nd week of pregnancy.

The findings

  • Women who reported health-conscious dietary patterns (a diet composed of oats, bran, fruits and salads) or traditional diets (those consisting of vegetables, red meat and poultry) were 23% and 16%, respectively, less likely to have high levels of anxiety symptoms compared to vegetarians and those who consumed processed foods and confectionery.
  • Women who did not consume any n-3 PUFA from seafood had a 53% higher risk of excessive anxiety symptoms compared to those who consumed over 1.5 grams/week.
  • Women who rarely or never consumed dark or oily fish had a 38% greater likelihood of anxiety compared to those who consumed this type of fish 1-3 times per week.
  • Women who adhered the most closely to a vegetarian diet were 25% more likely to experience excessive anxiety compared to those who followed a less vegetarian diet.

Limitations of the study

Diet and anxiety were investigated simultaneously — it may be that the women’s mood influenced their food choices. Moreover, physical activity was not accounted for.

What these results mean for you

Study author Dr Vaz highlighted that “in order to have a healthy pregnancy, women need to follow a healthy diet and not something special for pregnancy.”

What if you’re vegetarian?

“It is possible, but not proved, that this association with fish is due to the omega-3 fatty acid content of the fish,” said Dr Emmett, dietitian and study co-author. “Some vegetarians are happy to eat fish from time to time and we would encourage this especially as we are not sure what ingredient in fish is the most effective,” she added.

Not a fish fan? Ask your GP to recommend an omega-3 supplement. Other dietary sources of omega-3 include flax seeds and oil, nuts and seeds — bear in mind that these contain ALA, the shortest omega-3. For ALA to be assimilated by the body, it needs to be converted to EPA and DHA, the omega-3s naturally found in fish. And the issue here is that conversion is really low: only about 2-5% of ALA gets converted!

Recommendations from the NHS

  • Steer clear of fish that are high in mercury, namely shark, marlin, King mackerel, tilefish and swordfish.
  • Keep intake of oily fish to a maximum of two portions per week.
  • Avoid eating more than two fresh tuna steaks and four medium sized tuna cans per weeks.
  • White fish such as cod and plaice can be eaten regularly.

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