Pregnancy Diet: which Foods to Avoid and how to Combat Nausea

The pregnancy diet has a reputation full of prohibitions. From all sides, you hear what shouldn’t be eaten, what is risky and what to avoid altogether. Many women feel that during pregnancy, they have to give up half of the foods they normally love, just to ensure nothing endangers the baby. Added to this are typical difficulties such as nausea, constipation, heartburn or diabetes, which make nutrition an even greater challenge.

And although there’s often truth behind these recommendations, there’s no reason to be afraid. This article will teach you several clear rules that will keep your diet not only safe but also varied and tasty.

What Does a Safe Diet for a Pregnant Woman Look like?

Nutrition during pregnancy is not just about the right foods and nutrients, but also about food safety for mother and child. Especially when it comes to risky substances and microorganisms. It’s important to control the intake of heavy metals and prevent food contamination with harmful bacteria. These can endanger fetal development during pregnancy. Therefore, food safety deserves special attention.

How to Avoid Heavy Metals?

One of the substances that deserves increased attention during pregnancy is mercury. Its high intake can have a negative impact on the neurological development of the fetus. Most mercury is found in large marine predatory fish, as they live longer and accumulate higher amounts of this heavy metal during their lifetime. ^[11]

Fish with the Highest Mercury Content

• shark
• swordfish
• marlin
• king mackerel
• bigeye and bluefin tuna
• pike ^[7]

Apart from these types of fish, all others are allowed during pregnancy. You don’t have to give up salmon, trout or sardines.

Can a Pregnant Woman Eat Tuna?

The answer is yes, but be careful with your choice. Some species, specifically bigeye tuna and bluefin tuna, are unsuitable due to high mercury levels. But in this case, we also have a safe option – smaller species, such as skipjack tuna (Katsuwonus pelamis). This is commonly used in canned tuna. ^[7,17]

Since mercury, albeit in much lower amounts, can also be found in smaller fish species, you should stick to recommendations during pregnancy. Ideally, consume an allowed fatty sea fish twice a week – this way you’ll avoid unhealthy mercury intake while enjoying all the essential nutrients that fish offer. ^[3]

How to Avoid Salmonellosis and Listeriosis?

1. Salmonellosis

Salmonellosis is caused by the bacterium Salmonella enterica, which causes an intestinal infection accompanied by diarrhoea, vomiting and fever. Although it doesn’t directly threaten the fetus, it can lead to dehydration and severe exhaustion of the mother’s body, which can further cause complications.

How to Prevent Salmonellosis?

• cook food thoroughly
• avoid raw foods
• wash your hands after handling raw food
• store raw meat separately from cooked food
• use different kitchen equipment (especially cutting boards) for raw foods than for heat-treated ones
• thoroughly wash vegetables and fruits ^[3,15]

Which Foods to Avoid?

• raw and undercooked meat
• unpasteurised milk and dairy products
• raw or undercooked eggs
• raw fish and seafood

2. Listeriosis

Listeriosis is also a bacterial infection caused by the bacterium Listeria monocytogenes. In the general population, it often has a mild course, but in pregnancy, it can have serious consequences. It can lead to damage to the fetus’s nervous system, premature birth and even miscarriage.

How to Prevent Listeriosis?

• avoid risky foods
• thoroughly heat ready-to-eat foods ^[3]

Which Foods to Avoid?

• unpasteurised dairy products
• soft cheeses, such as camembert, cheeses with mould inside or, for example, bryndza (soft, tangy sheep cheese) made from unpasteurised milk
• raw or undercooked meat
• meat products bought at the deli counter
• smoked meats
• pâtés
• ready-to-eat meals that are not reheated before consumption
• foods that have been open and stored for a long time

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Why be Careful about Excessive Vitamin A Intake?

While vitamin A is important for the development of the baby’s vision, skin and immune system, in excessive amounts it can be harmful. Too high intake in the form of retinol, the animal form of vitamin A, can increase the risk of developmental disorders in the fetus, especially in the first trimester.

Foods such as liver and pâtés, which contain very high doses of retinol, are particularly risky. Pregnant women are therefore advised to avoid these foods. On the other hand, plant sources of vitamin A in the form of beta-carotene are safe. ^[2]

Which Foods are Risky During Pregnancy and What Not to Eat During Pregnancy?

Foods	Risk	Recommendation
Large marine fish (shark, swordfish, marlin, king mackerel, pike, bigeye/bluefin tuna)	High mercury content	Avoid them completely
Raw or undercooked meat	Risk of salmonellosis and listeriosis	Cook thoroughly
Unpasteurised milk and dairy products	Risk of listeriosis	Avoid them completely
Soft cheeses with mould	Risk of listeriosis	Avoid them completely
Deli meat products, smoked meats, pâtés	Risk of listeriosis	Avoid them or cook them thoroughly
Ready-to-eat meals without subsequent reheating	Risk of listeriosis	Always reheat before consumption
Eggs – raw or undercooked	Risk of salmonellosis	Eat them only well-cooked
Raw fish and seafood	Risk of salmonellosis and listeriosis	Avoid them or consume only when well-cooked
Liver, liver products, supplements with high vitamin A content	High vitamin A content, risk of teratogenicity	Significantly limit or avoid them completely, consult supplements with a doctor

Fluid Intake During Pregnancy

Did you know that during pregnancy, a woman’s blood volume increases by up to 45%? Since almost half of it is water, the need for fluids also increases. The future mother’s body is supplying not only herself but also the baby, and at the same time producing amniotic fluid, which protects and nourishes the fetus. Added to this are hormonal changes, accelerated metabolism and increased sweating or kidney activity, all of which are factors that accelerate water loss. ^[8,12]

Sufficient fluid intake is thus not just about quenching thirst, but helps prevent complications such as the risk of preeclampsia, gestational diabetes or premature birth. Regular fluid intake is therefore crucial during pregnancy. ^[12]

How much Fluid should a Pregnant Woman Drink?

Recommending exactly how much a woman should drink during pregnancy is quite challenging because the need for fluids depends on several factors. These include climatic conditions, amount of physical activity, degree of sweating or health condition. It even depends on how the woman eats, because we also get water from food.

• According to EFSA, a pregnant woman should consume at least 2300 ml of fluids daily, which is 300 ml more than for non-pregnant women. This intake includes water from both drinks and foods. ^[13]
• DACH recommends a daily fluid intake of at least 2700 ml. ^[5]

What Fluids to Choose?

Of course, the best choice for everyday fluid intake is plain water. Unsweetened fruit or some herbal teas can also be a great addition. On the other hand, sweetened drinks, juices or flavoured mineral waters with high sugar content should remain the exception rather than the rule.

You can read about why to drink sweetened beverages only occasionally in the article Where Are Liquid Calories Hiding, and How Do These Empty Calories Prevent You from Losing Weight?

Which Herbal Teas are Suitable?

Not all herbs are safe during pregnancy, but some types of teas can be a pleasant and beneficial addition to fluid intake.

• Peppermint tea is popular for bloating and impaired digestion.
• Chamomile tea is among the safest teas for pregnant women. It’s also used for digestive issues.
• Ginger tea is popular for morning sickness.
• Fennel tea helps against bloating.
• Raspberry leaf tea is often used to ease labour. ^[9]

Although these teas have positive effects during pregnancy, they should be consumed in moderation. Excessive doses of some of them can be harmful. It’s best to alternate between different teas.

Is Coffee Allowed During Pregnancy?

Coffee during pregnancy doesn’t have to be taboo, and you certainly don’t need to give it up. You just need to drink it in moderation. You should monitor the amount you drink due to its caffeine content, as excessive intake can lead to lower birth weight of the baby or slowed intrauterine growth.

WHO and EFSA recommend not exceeding a daily intake of 200 mg of caffeine, which corresponds to approximately 2-3 cups of espresso per day. But be careful, caffeine is also found in cola drinks, tea, energy drinks and chocolate. If you keep all its sources in mind, you can enjoy your dose of caffeine even during pregnancy, safely every day. ^[3]

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Is Alcohol Allowed During Pregnancy?

The experts’ answer to this question is clear – alcohol should be completely avoided during pregnancy. There is no safe amount that couldn’t potentially harm the developing fetus. Even small doses of alcohol can increase the risk of so-called fetal alcohol syndrome, which is a set of mental and physical disorders in the child caused by alcohol. ^[3,14]

Most Common Pregnancy Discomforts and How to Address Them through Nutrition

Pregnancy is a significant strain on the body. It undergoes hormonal changes, the uterus grows, and digestion changes, which can cause discomfort. We’ll discuss how to deal with the three most common issues.

1. Constipation

Constipation during pregnancy can be caused by increased levels of the hormone progesterone, which slows down digestion. More water is also absorbed from the digestive tract, and in later stages of pregnancy, the condition is worsened by the enlarged uterus pressing on the intestines. ^[10]

What Can Help with Constipation?

• increased fluid intake
• increased intake of fibre
• regular exercise
• gentle laxatives (after consulting with a doctor)
• taking probiotics

2. Pregnancy Nausea and Vomiting

Nausea and vomiting are the most common discomforts during the first trimester and affect up to 70-80% of pregnant women. They are caused by hormonal changes, as well as changes in smell and digestion. Nausea usually subsides after the first trimester. ^[6]

What Can Help with Nausea and Vomiting?

• more frequent, smaller meals
• avoiding strong odours and foods with strong flavours
• dry foods (crackers, dry biscuits, etc.)
• ginger (in the form of tea or supplement)
• in more severe cases, anti-nausea medications (antiemetics) after consulting with a doctor ^[6]

3. Heartburn

Heartburn, also known as gastroesophageal reflux (GERD), affects up to 80% of pregnant women, and its occurrence increases with advancing pregnancy. Its causes include hormonal changes, pressure of the growing uterus on the stomach, and slowed digestion. ^[1]

What Can Help with Heartburn?

• eating last meal 2-3 hours before lying down in bed
• sleeping with the head elevated by 10-15 cm
• lying on the left side
• loose clothing that doesn’t press on the stomach
• smaller portions more frequently throughout the day
• avoiding spicy, fatty, and acidic foods
• limiting coffee, chocolate, and carbonated drinks (if they bother you) ^[1,3]

What is Gestational Diabetes and how Can Diet Help?

Gestational diabetes is a disorder of blood sugar regulation that typically appears between the 24th and 28th week of pregnancy. If left untreated, it can increase the risk of complications for both mother and child, including excessive birth weight or premature birth.

The good news is that proper nutrition plays a key role in managing it. What helps?

• regular eating habits
• a diet with a low glycaemic index
• a diet rich in fibre, complex carbohydrates, and quality proteins
• regular exercise ^[16]

Should a Pregnant Woman Exercise?

The idea that a pregnant woman should rest on the couch for months is no longer valid. On the contrary, exercise is one of the best gifts you can give to yourself and your baby. Regular exercise helps maintain a healthy weight, reduces the risk of gestational diabetes, preeclampsia, and back pain and also improves sleep and mental well-being. Of course, if pregnancy is accompanied by health problems, physical activity must be adjusted accordingly. However, when you’re healthy, pregnancy is not an obstacle to exercising.

The type and intensity of exercise should be adapted to what the body was accustomed to before pregnancy. A woman who regularly exercises and lifts weights can often continue with alterations for several months after becoming pregnant. Conversely, if someone is just starting with exercise, it’s not the ideal time to dive into demanding workouts. Beginners are recommended to engage in lighter forms of exercise, such as walking, swimming or special exercises for pregnant women, like prenatal yoga. Every activity should be safe, enjoyable, and ideally consulted with a doctor. ^[4]

What Should You Take Away from This?

Nutrition during pregnancy is not just about what to add, but also what to reasonably avoid. Some foods may pose a risk to fetal development, but on the other hand, you shouldn’t restrict yourself too much. It’s enough to know a few basic safety rules. It’s important to thoroughly cook food, avoid raw dishes, exclude fish high in mercury and avoid alcohol. This way, you’ll protect both your health and your baby’s.

If your pregnancy is complicated by nausea or gestational diabetes, these can be managed too. With the right diet, you can alleviate them and soon enjoy your favourite foods again. Because it still holds that food should remain a joy even during pregnancy.

Do you finally have a clear understanding of what a proper pregnancy diet looks like? If you know someone who could also use advice, share this article with them.

Sources:

[1] ALTUWAIJRI, M. Evidence-based treatment recommendations for gastroesophageal reflux disease during pregnancy: A review. – https://www.ncbi.nlm.nih.gov/pmc/articles/PMC9439837/

[2] BASTOS MAIA, S. et al. Vitamin A and Pregnancy: A Narrative Review. – https://www.ncbi.nlm.nih.gov/pmc/articles/PMC6470929/

[3] BDA Pregnancy and diet. – https://www.bda.uk.com/resource/pregnancy-diet.html

[4] COOPER, D.B. – YANG, L. Pregnancy And Exercise. – http://www.ncbi.nlm.nih.gov/books/NBK430821/

[5] EFSA PANEL ON DIETETIC PRODUCTS, NUTRITION, AND ALLERGIES (NDA) Scientific Opinion on Dietary Reference Values for water. – https://onlinelibrary.wiley.com/doi/abs/10.2903/j.efsa.2010.1459

[6] LEE, N.M. – SAHA, S. Nausea and Vomiting of Pregnancy. – https://www.ncbi.nlm.nih.gov/pmc/articles/PMC3676933/

[7] PROGRAM, H.F. Advice about Eating Fish. – https://www.fda.gov/food/consumers/advice-about-eating-fish

[8] SOMA-PILLAY, P. et al. Physiological changes in pregnancy. – https://www.ncbi.nlm.nih.gov/pmc/articles/PMC4928162/

[9] TERZIOGLU BEBITOGLU, B. Frequently Used Herbal Teas During Pregnancy – Short Update. – https://www.ncbi.nlm.nih.gov/pmc/articles/PMC7384490/

[10] TROTTIER, M. et al. Treating constipation during pregnancy. – https://www.ncbi.nlm.nih.gov/pmc/articles/PMC3418980/

[11] WEICHSELBAUM, E. et al. Fish in the diet: A review. – https://onlinelibrary.wiley.com/doi/abs/10.1111/nbu.12021

[12] ZHANG, N. et al. Associations between hydration state and pregnancy complications, maternal-infant outcomes: protocol of a prospective observational cohort study. – https://pubmed.ncbi.nlm.nih.gov/32033597/

[13] Dietary Reference Values | DRV Finder. – https://multimedia.efsa.europa.eu/drvs/index.htm

[14] Drinking alcohol during pregnancy is harmful to the unborn child | WHO | Regional Office for Africa. – https://www.afro.who.int/news/drinking-alcohol-during-pregnancy-harmful-unborn-child

[15] Listeria and Salmonella risks during pregnancy | ACT Nutrition Support Service – https://actnss.org/resources/listeria-and-salmonella-risks-during-pregnancy

[16] Managing & Treating Gestational Diabetes – NIDDK. – https://www.niddk.nih.gov/health-information/diabetes/overview/what-is-diabetes/gestational/management-treatment

[17] Size, species, capture location: What makes tuna get high on mercury? | The Pacific Community. –