Pregnant women are advised to eat only cooked tuna and avoid kinds with high mercury levels in order to optimize the benefits while limiting the hazards.
Tuna is rich in nutrients, including eicosapentaenoic acid (EPA) and docosahexaenoic acid (DHA), which are essential for brain and nervous system development (1Trusted Source). However, most tuna types contain high levels of mercury, which has been linked to various health and developmental issues.
The Nutritional Benefits of Tuna During Pregnancy
Tuna, a popular and nutritious fish, offers a variety of essential nutrients that are especially beneficial during pregnancy. When pregnant, ensuring an adequate intake of nutrients is vital for the health and development of both the mother and the growing baby. Tuna is rich in protein, omega-3 fatty acids (EPA and DHA), vitamins, and minerals, all of which play a crucial role in supporting pregnancy.
Protein: Essential for Growth and Development
Protein is a cornerstone nutrient for both the mother and the developing fetus. During pregnancy, the body’s demand for protein increases significantly, as it supports the growth of tissues, organs, and cells in both the mother and the baby. Protein helps in the formation of the baby’s skin, muscles, and internal organs. It also plays a crucial role in producing breast tissue for breastfeeding after birth. Adequate protein intake is essential to avoid complications such as intrauterine growth restriction (IUGR), which refers to when the baby is smaller than expected for gestational age, as well as the risk of low birth weight or even miscarriage.
It is important to note, however, that while protein is necessary, too much protein can also lead to problems. Excessive intake may place undue strain on the kidneys and other organs, so maintaining a balanced protein intake is essential.
A serving of tuna provides a rich source of high-quality protein, which is essential for supporting the body’s increased protein needs during pregnancy.
Omega-3 Fatty Acids: EPA and DHA for Brain and Eye Development
One of the most significant benefits of consuming tuna during pregnancy is the presence of long-chain omega-3 fatty acids—specifically EPA (eicosapentaenoic acid) and DHA (docosahexaenoic acid). These essential fatty acids are crucial for the development of the baby’s brain and eyes. DHA, in particular, makes up a significant portion of the brain and retinal tissue. Therefore, getting enough DHA during pregnancy is vital for ensuring optimal brain development and cognitive function in the infant.
EPA and DHA are also linked to numerous health benefits during pregnancy. Studies have shown that these omega-3s may reduce the risk of preterm birth, poor fetal growth, maternal depression, and childhood allergies. Additionally, omega-3 fatty acids help regulate the body’s inflammatory response and support the development of a healthy immune system. Pregnant women are often advised to increase their intake of omega-3-rich foods, and tuna is an excellent source of these beneficial fats.
A 3.5-ounce (100-gram) serving of light canned tuna contains a significant amount of EPA (25 mg) and DHA (197 mg), amounting to around 63–100% of the daily recommended intake for pregnant women. These omega-3s are also known to promote the health of the placenta, ensuring proper nutrient exchange between mother and baby.
Vitamin D: Supporting Immunity and Bone Health
Tuna is a natural source of vitamin D, a fat-soluble vitamin essential for bone health and immune system function. During pregnancy, vitamin D helps the body absorb calcium, which is critical for the development of the baby’s bones and teeth. Adequate vitamin D levels also support the mother’s immune system, helping to protect against infections and illnesses.
In addition, some studies suggest that sufficient vitamin D levels during pregnancy may help reduce the risk of complications such as preeclampsia (a condition marked by high blood pressure and damage to organs like the kidneys) and miscarriage. Vitamin D deficiency has been linked to an increased risk of both maternal and fetal health problems. Tuna’s vitamin D content can contribute to meeting daily vitamin D needs.
While tuna contains small amounts of vitamin D, it is a good dietary source for pregnant women, especially since vitamin D is found in limited foods, and sunlight exposure may not always provide adequate amounts, especially in areas with limited sunlight or during the winter months.
Iron: Vital for Red Blood Cell Production
Iron is another important nutrient found in tuna that plays a key role in the healthy development of the baby’s brain and nervous system. During pregnancy, a woman’s blood volume increases, which makes her more susceptible to iron deficiency. Adequate iron intake helps support the production of red blood cells, which are essential for carrying oxygen to both the mother and the baby. Iron also supports the development of the baby’s blood circulation and organ systems.
Iron deficiency during pregnancy can lead to anemia, which can cause fatigue, dizziness, and shortness of breath. In more severe cases, iron deficiency anemia increases the risk of complications such as preterm birth, low birth weight, and maternal mortality. Including iron-rich foods like tuna in the diet can help prevent these risks. A 3.5-ounce (100-gram) portion of tuna provides 9% of the recommended daily value for iron.
Vitamin B12: Supporting the Nervous System
Vitamin B12 is an essential nutrient for the production of red blood cells and the maintenance of the nervous system. This vitamin is necessary for the formation of DNA and supports the baby’s neurological development. During pregnancy, adequate vitamin B12 levels help ensure that the developing baby’s nervous system functions properly.
A deficiency in vitamin B12 during pregnancy can increase the risk of miscarriage, preterm birth, birth defects, and other complications. Tuna is an excellent source of vitamin B12, providing around 107% of the daily value per 3.5-ounce (100-gram) serving. This makes tuna an especially important food for pregnant women to maintain proper B12 levels.
The Potential Risks of Eating Tuna During Pregnancy
Despite the numerous health benefits of tuna, it is important to consider potential risks, particularly regarding mercury content. Mercury is a toxic substance found in fish and seafood, with higher levels in larger, predatory fish like tuna.
Mercury in Tuna: Risks to the Baby’s Brain and Nervous System
Mercury is naturally present in the environment but is also introduced through industrial pollution. Fish accumulate mercury as they feed on smaller fish that contain the toxin. Tuna, being a large predatory fish, tends to have higher mercury levels than smaller fish. Excessive mercury intake during pregnancy can pose significant risks to the developing baby’s brain and nervous system. High mercury exposure can lead to developmental issues such as learning difficulties, delayed motor skills, speech and memory deficits, and lower IQ.
In extreme cases, excessive mercury intake can result in birth defects, seizures, and even infant death. While some studies suggest that mercury exposure may not always have negative effects if the mother consumes fish regularly, the general advice is to limit mercury exposure during pregnancy.
Pregnant women should avoid consuming raw or undercooked tuna, as it may increase the risk of exposure to harmful bacteria like Listeria monocytogenes, which can cause severe infections and complications in the fetus.
Safe Tuna Consumption Guidelines
The risk of mercury exposure is cumulative, meaning it builds up over time with continued consumption. To minimize the risks, the U.S. Food and Drug Administration (FDA) recommends that pregnant women limit their intake of tuna to 8–12 ounces (225–340 grams) of fish per week. This should include no more than:
- 12 ounces (340 grams) of canned light tuna or other low-mercury fish such as cod or tilapia
- 4 ounces (112 grams) of yellowfin, albacore tuna, or other medium-mercury fish
Pregnant women should also avoid high-mercury fish like swordfish, shark, and bigeye tuna. Guidelines for safe tuna consumption vary between countries, but they generally align with the FDA’s recommendations.
Conclusion: Balancing the Benefits and Risks of Tuna During Pregnancy
Tuna is a highly nutritious food that provides essential nutrients like protein, omega-3 fatty acids, vitamin D, iron, and vitamin B12, all of which are important during pregnancy. These nutrients support the healthy development of the baby’s brain, eyes, nervous system, and immune system, as well as the overall health of the mother. However, due to the potential risks associated with mercury exposure, it is important to consume tuna in moderation, adhering to recommended guidelines for safe intake.
Pregnant women should enjoy the benefits of tuna while being mindful of mercury levels. By following guidelines for safe fish consumption, they can continue to include tuna in their diet while minimizing any potential risks to the baby’s health.