The purpose of this article is to examine the available literature on the dietary requirements of women during pregnancy and lactation. We have summarized evidence relating to the requirements for macronutrients, micronutrients, and maternal conditions that are associated with nutrient deficiencies.
Increasing Energy During Pregnancy
Increasing energy intakes during pregnancy while keeping the macronutrient distribution the same appears to be crucial. Maternal nutritional requirements state an increased calorie and protein intake as it is shown in the table below.
Protein synthesis is crucial during pregnancy; therefore, protein intake requires the most attention of the macronutrients to ensure proper fetal growth.
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Regarding fat intake, it is discussed how this differs from the mother’s fat intake during pregnancy and lactation which should not be increased. It should only shift so the mother consumes more polyunsaturated fatty acids, such as docosahexaenoic acid (DHA).
There was substantial evidence on the role of DHA in infant neural development. DHA cannot be made in our bodies, therefore, it is important that the mother consumes adequate amounts during her pregnancy.
The best source of DHA in our diets is fish. Although there are concerns about the safety of consuming fish while pregnant due to the risk of contamination, consuming 1-2 or up to 3-4 servings of fish per week during pregnancy is safe and promotes proper fetal development and meets maternal nutritional requirements.
Micronutrient intake during pregnancy should be taken into consideration due to the significant consequences of deficiencies. More information with regards to the recommended dosage and food options for each micronutrient can be found in the table below.
Also, Iodine has an important role in growth, metabolism, and the development of organs and tissues. The best sources of iodine are fish and shellfish. It is recommended that pregnant and lactating women consume 200ug/day of iodine. Iodine deficiency can have serious consequences during pregnancy such as birth defects, brain damage, and spontaneous abortion.
Vitamin D can be found in both animal and plant products although their levels in the body are also affected by exposure to sunlight. Deficiency in Vitamin D is common during pregnancy and carries the risk of gestational diabetes and pre-eclampsia. Therefore, supplementation is recommended to decrease the risk of pre-eclampsia, low birth weight, and pre-term delivery.
Pregnancy & Dietary Restrictions
To minimize the risk of major nutrient deficiencies, pregnant and breastfeeding mothers should be monitored, in particular, those who exclude whole categories of foods from their diet for ethical and/or health purposes. It has been proved that the eliminating specific nutrients from the diet of healthy mothers even of allergenic foods (soy, cow’s milk, eggs, peanuts, fish and shellfish) will be ineffective to prevent infant allergies.
Further, in pregnant women and lactating with no history of gluten sensitivity, a gluten-free diet appears not to be appropriate; rather it can lead to micronutrient deficiencies such as folate, calcium, iron, and zinc. This is even more pronounced in those who are not consuming cereals containing gluten.
As vegan diets are becoming more popular, more attention should be paid to consider appropriate alternatives for diets are lacking animal-based foods, including eggs and milk during pregnancy and lactation. A growing body of literature highlighted the higher risk of iron and vitamin B 12 deficiency and low birth weight are associated with vegetarian or strictly vegan diets, where no adverse effects were observed in the fetus.
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Nutrition & Budget
Another notable issue, concerning in particular low-income populations, is the low consumption of fruits and vegetables where fortified products are not easily accessible. This is associated with insufficient intakes of specific micronutrients. Consuming supplements to provide a range of required vitamins and minerals can effectively lower the risk of pre-term delivery and infants of low weight at birth. There is evidence showing that mixing multiple micronutrients in a single delivery mechanism as a cost-effective way to meet several maternal nutritional requirements.
Other Health Factors
Other lifestyle factors can also affect nutrient deficiencies during pregnancy such as; smoking; obesity and previous bariatric surgery which increase the risk of pregnancy complications; exclusion diets which can increase the risk of nutrient deficiencies; adolescence which increases the risk of low birth weight and preterm delivery; multiple and repeated pregnancies which increase the risk of depleting the mother’s stores of nutrients; and previous pregnancy-related complications. These women need special attention when evaluating their diet to reduce the risk of further complications.
Lifestyle and dietary habits are extremely important before and during pregnancy and breastfeeding to ensure the health of both the mother and the fetus.
Take Away Message
To be mindful and well-informed that dietary intakes are often insufficient during pregnancy and lactation and that special attention needs to be paid to women of child-bearing age, especially if they have any of the above lifestyle factors that may affect nutrient deficiencies during their pregnancy.
Kramer, M.S.; Kakuma, R. Energy and protein intake in pregnancy. Cochrane Database Syst. Rev. 2003.
Ho A, et al., Nutrition in pregnancy, Obstetrics, Gynaecology and Reproductive Medicine (2016), http://dx.doi.org/10.1016/j.ogrm.2016.06.005