Vitamins and Minerals During Pregnancy
Although all vitamins and minerals contribute to the proper functioning of the human body, some are essential for pregnant women: folic acid, iron, calcium, vitamin D, fiber, iodine, choline, and omega-3. They play an essential role in all stages of embryo and fetal growth.
Why take vitamin and mineral supplements?
Pregnant women are advised to take a daily prenatal vitamin and mineral supplement. Sometimes the diet does not provide enough of certain nutrients that are crucial during pregnancy. The multivitamin helps fill in the gaps that may occur during the 9 months of pregnancy.
The multivitamin should contain 0.4 mg to 1 mg of folic acid and iron (16 mg to 20 mg). Amounts may vary depending on your doctor’s recommendations.
The Society of Obstetricians and Gynaecologists of Canada notes that a pregnant woman may need calcium, vitamin D, or iron supplements in addition to prenatal multivitamins, depending on her diet and health. Discuss this with your doctor.
The multivitamin should contain a maximum of 10,000 IU of vitamin A. Too much of this vitamin is toxic and can cause congenital disabilities. However, multivitamins for pregnant women are far from this maximum. They are, therefore, perfectly safe.
Folic acid (vitamin B9)
This vitamin is essential, especially in early pregnancy. It is involved in the formation of the spine and brain of the embryo from the first days after conception.
When a woman learns she is pregnant, this crucial stage has already passed. This is why doctors recommend that women planning a pregnancy take a multivitamin containing folic acid 2 to 3 months before they conceive. This is also why it is recommended that all women who may become pregnant without planning it (“by accident”) take a folic acid supplement daily.
Throughout pregnancy, folic acid is involved in forming new tissues, blood cells, the brain, and the nervous system. Folic acid deficiency can cause growth retardation, congenital disabilities, or neural tube defects (e.g., spina bifida). Physical disabilities or severe mental deficiencies may result.
Pregnant women’s daily folic acid requirement ranges from 0.4 mg to 1 mg per day. Women with a family or personal history of neural tube defects have an even higher requirement.
Folic acid is added to white flour in Canada and the United States. It is usually added to cornmeal and pasta. Pasta made in Italy, however, is not fortified with folic acid. Check the ingredient list to be sure.
To properly absorb iron from food, the body needs vitamin C. Tomatoes, peppers, broccoli, strawberries, oranges, and other citrus fruits are good sources of vitamin C.
Iron is found in red blood cells. In particular, it allows the red blood cells to pick up oxygen in the lungs and transport it throughout the body and to the fetus through the placenta. Pregnant women need more iron because their blood volume increases. In addition, they need to provide it to their unborn baby. The baby’s iron stores at birth last most for the first 6 months of life.
Adequate iron intake reduces the risk of premature delivery, low birth weight babies, and early infant mortality.
Iron deficiency can cause anemia. It can cause fatigue and faster shortness of breath with exercise. A blood test can detect deficiency. Women who are vegetarians and those who have close or multiple pregnancies are more likely to be iron deficient.
Other sources of iron
Some vegetables such as greens (kale, spinach, asparagus, snow peas, etc.), beets, and potatoes with skins on contain some iron. However, the iron in plant foods (vegetables, legumes, fortified breakfast cereals, and nuts) and eggs are less well absorbed by the body than the iron in meat and fish. That’s why vegetarians need twice as much iron to meet their needs.
How can I help my body absorb iron?
When you eat plant foods that contain iron, serve them with a fruit or vegetable rich in vitamin C (e.g., bell pepper, tomato, turnip, cauliflower, broccoli, sweet potato, Brussels sprouts, grapefruit, clementine, tangerine, strawberry, raspberry, kiwi, melon, and mango). Vitamin C will help your body absorb iron.
Also, avoid drinking tea or coffee with a meal or within an hour of a meal, as these drinks contain substances that interfere with the absorption of iron and calcium.
Iron, nausea, and vomiting
The Society of Obstetricians and Gynaecologists of Canada recommends that pregnant women with nausea and vomiting stop taking prenatal multivitamins containing iron because iron can increase nausea. These multivitamins can safely replace with a folic acid supplement or low iron prenatal vitamins. This is because a pregnant woman’s need for iron does not usually increase during the first trimester.
Calcium requirements increase by 30% during pregnancy. The fetus needs it to build its skeleton. Calcium is used to build bones and teeth. Suppose the pregnant woman’s diet is not rich enough in calcium. In that case, the future baby will draw it directly from the mother’s reserves. Calcium also helps maintain good blood pressure during pregnancy.
Supplements are recommended if the pregnant woman eats little food rich in calcium. A supplement of 1 g of calcium per day would help reduce the risk of preeclampsia (high blood pressure during pregnancy) in women with insufficient calcium intake. In Canada, this is the case for approximately 41% of women aged 19 to 50. It is, therefore, appropriate to seek advice from a nutritionist.
Vitamin D acts in tandem with calcium. It allows calcium to be assimilated and fixed on the bones. It is also involved in cell growth and immune system function. Adequate vitamin D levels during pregnancy provide lifelong benefits to the pregnant woman and her child.
Although many foods contain or are fortified with vitamin D, the primary source is sunlight. This is why people in northern countries, such as Canada, often have low vitamin D levels from October to April. So even if you eat foods that contain vitamin D, you may still need to take supplements. The prenatal multivitamin usually contains vitamin D.
Studies suggest that supplementing pregnant women with vitamin D may help reduce the risk of preeclampsia, gestational diabetes, and low birth weight babies.
*Pregnant women can eat canned light tuna without concern. However, they should limit their consumption of fresh or frozen tuna and canned albacore tuna. For more information, see our Food During Pregnancy fact sheet.
The benefits of omega-3 for pregnant women are increasingly well documented. These good fats contribute to the health of the pregnant woman and the fetus. Omega-3s are involved in the development of the brain and eyes of the future baby. In addition, they have been shown to help keep the mother’s spirits high throughout the pregnancy and after birth.
Generally, it is said that the population does not eat enough omega-3 fats. For this reason, it is recommended that pregnant women eat at least two meals of oily fish per week (200 to 350 g of cooked fish in total).
A review of 70 studies concluded that taking omega-3 supplements during pregnancy reduced the risk of preterm (before 37 weeks) and very preterm (before 34 weeks) births. For women with low-risk pregnancies, however, there would be no benefit to taking an omega-3 supplement. There would be no disadvantages, but it is better to eat fish, as the combination of omega-3 with other nutrients is more beneficial.
Other sources of omega-3
Other foods can provide omega-3s, such as walnuts, canola oil, and flax or chia seeds. However, these plant-based foods provide less omega-3 than oily fish because the body absorbs them less well.
Fiber reduces the risk of constipation, which is common during pregnancy. Hormonal changes and iron supplements often cause it.
Eating fiber-rich foods daily and drinking plenty of water are essential to prevent or treat constipation. Foods that are naturally high in fiber (such as those listed below) are more effective than those with concentrated fiber (such as oatmeal or inulin).
Iodine is a mineral found in tiny amounts in the body. It allows the body to make thyroid hormones essential for bone formation, muscle contraction, heartbeat, and nutrient absorption. Iodine also contributes to fetal brain growth, and a deficiency could lead to developmental problems.
Table salt sold in Canada has been fortified for over 100 years. However, there are recommendations to reduce the salt content of foods, which results in lower iodine intakes for the population. Commercially processed foods – very salty – are not fortified with iodine. The solution is to cook as much as possible and add small pinches of salt here and there.
Choline is an essential nutrient in the fetal brain’s development and may help prevent neural tube defects. It also contributes to the proper functioning of the placenta.
This vitamin is rarely included in supplements for pregnant women. It is therefore recommended to eat foods containing it regularly.
Vitamin B12 is essential for the manufacture of red blood cells and the proper functioning of the nervous system of the fetus. It works with folic acid to make DNA (genetic material).
Because this vitamin is found almost exclusively in animal foods, women who are vegetarians or eat very little meat, fish, eggs, and dairy products need to pay special attention. Their multivitamin supplement must contain it.
A vitamin B12 deficiency could affect the child’s cognitive functions and cause anemia, memory problems, and other permanent neurological problems in the mother.
Other vitamins and minerals
Vitamin C, other B vitamins, zinc, magnesium, etc., all contribute to a healthy pregnancy. They are less talked about because a varied diet easily meets the needs of these nutrients. The ones that are the subject of this sheet are sometimes more difficult to obtain.
Things to remember
1. Folic acid supplementation is strongly recommended for at least 3 months before conception.
2. A multivitamin supplement specially designed for pregnant women is recommended throughout the pregnancy.
3. A varied diet is essential to provide the pregnant woman and her baby with all the necessary nutrients.