The importance of a well-balanced diet during pregnancy : Micronutrients

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As we have seen in the « Macronutrients article », Carbohydrates, fats and proteins cannot work alone. Once the sources are ingested, macronutrients need help to begin their metabolization and that is when the Micronutrients come into play.

Moreover, during pregnancy and lactation, nutritional requirement increase to support fetal and infant growth as well as maternal metabolism and tissue development specific to reproduction. Therefore, in order to provide the nutritional requirements and avoid fetal growth retardation and congenital anomalies, a proper vitamins and minerals intake is essential.

Vitamins :

Vitamins are essential nutrients that are necessary for many metabolic tasks, such as building coenzymes that are required for periodic table of vitaminssome enzymes (macromolecules responsible of metabolic processes that sustain life) to function. They are classified in three sections ; 1 : fat-soluble vitamins, identified by A, D, E and K. 2 : water-soluble, identified by C, Folate and B’s. 3 : phytochemicals, bioactive molecules that are differentiable by the color of vegetables and fruits.

Since this article looks mainly into the pregnancy state, we will talk only about the vitamins that could make a difference in preventing some diseases relative to baby conception. But keep in mind that they all are important in a healthy diet.

A

Used as a coenzyme precursor for energy production and protein metabolism, Vitamin A is needed in high amount, because they both are elements in tissue growth.

To avoid 40% of maternal mortality, the intake recommended of Vitamin A and B-carotene should increased by 10% in the maternal diet. However, an excess of Vitamin A during early pregnancy can cause birth defects (functional or structural abnormalities that cause physical or mental disability, some may be fatal).

Mostly ingested via supplementation, vitamin A can be found in vegetables like carrots or more specifically in green vegetables like collard greens and spinach. They are in greater amount in skinned sweet potatoes too. But the best Vitamin A dietary source is animal liver meat, however be aware of the cholesterol found in abundance in this meat. Also Vitamin A is unstable when exposed to heat and oxygen, so a quick cooking method is preferred.

D

Vitamin D is essential to ensure the absorption and use of calcium and phosphorus, in order to avoid several disorders related to the calcium metabolism such as neonatal hypocalcemia (low level blood calcium in the newborn), tetany (involuntary contraction of muscles), infant hypoplasia (incomplete development) of tooth enamel, or maternal osteomalacia (defective bone mineralization).

To ensure the postnatal weight and length gains in infants, a high amount of vitamin D is necessary. However, the natural way to find this vitamin is in the exposure to sunlight. Obviously, deficiency is reported in latitudes where the amount of ultra violet light is not sufficient for Vitamin D synthesis. Therefore, supplementation, fortified foods (cow, soy or rice milk) and oily fish (salmon, sardines…) are the main ways to absorb the recommended vitamin D intake.

Furthermore, a Vitamin D deficiency in growing children could causes rickets (disease that is characterized by the softening of the bones). Vitamin D supplementation in the freshly born baby’s diet, is very important.

K

Vitamin K is not efficiently transferred through the placenta during gestation. As a result the intestinal tract of the newborn does not yet have vitamin K, which produces the gut flora. Thus, such as Vitamin D, Vitamin K is routinely given at birth to prevent hemorrhaging and deficiencies at birth.

Folate

Folate, which stable form is folic acid, participates in DNA synthesis and is involved in amino acid synthesis.

Furthermore, it is particularly needed during the early pre conceptional pregnancy (two months before the pregnancy to six weeks of gestation) to ensure embryonic tissue development and prevent malformation of the neural tube (primitive nervous system of the embryo). Both insufficient and excessive intake could be a risk factor for neural tube defects resulting in spina bifida (fetus vertebra overlying the spinal cord which are not fully formed and remain unfused and open) and anencephaly (absence of a major portion of the brain, the skull or the scalp) from which most babies do not survive.

46% to 70% neural tube defects can be prevented by adequate folate supplementation before and during the pregnancy period. 600 micrograms per day during pregnancy is the proper intake of folate and can be found, again in green vegetables like spinach, asparagus, turnip greens, and animal liver meat but also in lentils, egg yolk, sunflower seeds and avocados. Moreover, the cereal industry, in industrialized countries, artificially fortifies grain products with folic acid.

Minerals :

vitamins and mineralsInvolved in the process of building tissues as well as the activation, regulation, transmission, and control of metabolic processes, minerals are classified in two groups. 1 : Major minerals (calcium, phosphorus, sodium, potassium, magnesium, chloride and sulfur), called « major » because of their recommended daily intake which is higher than 100mg. 2 : Trace minerals, called that way because of their daily recommended intake which is less than 100/mg.

Calcium

Calcium, along with vitamin D, phosphorus and magnesium is essential for fetal bone and teeth development as well as for the mother’s health and blood clotting. An ideal calcium intake could help regulate gestational hypertension, which is a physiological response, in the early stage of pregnancy, to maintain proper transportation of nutrients and oxygen to the fetus.

The milk industry provides calcium in abundance through dairy products, but personally, as a lactose intolerant individual, I ingest calcium through almonds, sardines, sesame seeds, oranges and green vegetables which are also filled with plenty of other nutrients like Vitamins A & B.

Iron

Iron-deficiency anemia is the most common nutritional deficiency and affects 24.8% of people worldwide, and almost half of those people (42%) are (mostly poor) pregnant woman. Furthermore, iron-deficiency anemia could be associated with perinatal maternal death, infant mortality and premature delivery. Used to increase the hemoglobin synthesis that is required for the greater maternal blood volume and the baby’s necessary prenatal storage of iron, maternal intake of iron is difficult, almost impossible, to ingest naturally without supplementation.

Nevertheless it is possible to increase the absorption and ingestion by consuming vitamin C rich foods, avoiding foods that inhibit iron absorption (whole-grain cereals, tea, coffee…), eating iron rich foods (animal liver meat, clams, soybeans, spinach…) and taking supplements.

With all these sources, pregnant women should easily attain the 27 milligrams of recommended daily intake.

But, be mindful that in the case of excessive consumption, Iron toxicity could rapidly happen and the poisoning could affect the cardiovascular system, the central nervous system, the kidneys, the liver, and the hemotologic system and could even be fatal.

Iodine

Essential for ensuring a proper  thyroid gland function, iodine, if insufficient, could lead to fetal hypothyroidism resulting in severe mental retardation. According to « The World Health Organization » twenty million people worldwide have brain damage that could have been prevented by iodine maternal supplementation. The iodine deficiency is prevalent in geographic locations where the soil is poor in iodine.

220 micrograms per day is the recommended iodine intake during pregnancy to ensure proper fetus brain development.

In addition to supplementation, iodine is mostly naturally found in iodized salt, seafood and foods grown in a soil rich in iodine.

Micronutrients intake can be very tricky thus dangerous if it is not well-balanced.

It is known that infant who are born from mothers who took vitamin C in excess during pregnancy, may develop rebound scurvy after birth, when their high doses of Vitamin C disappear. Also cretinism (physical deformity, dwarfism, mental retardation) could occur in children born from mothers who followed a diet poor in Iodine during and before pregnancy. Rebound effects teach us that consistency is a key for a healthy lifestyle.

We have also learnt that a lot, or even any kind, of diseases could be avoided by pregnant women, as well as anyone  else, thanks to what we choose to eat.

In the end, the best way to make decisions regarding a proper diet is to ask for a physician’s advice.

References :

1. Physiology of pregnancy, by Mel. C. Barclay

2. Dietary supplement use in women : current status and future directions, by Mary Frances Picciano – 2003

3. Physiology of pregnancy and nutrient metabolism, by Janet C. King – 2000

4. Maternal nutrition during pregnancy and health of the offspring, by M.S. Martin-Gronert & S.E. Ozanne – 2006

5. Williams’ Basic Nutrition and Diet Therapy – 14th edition, Stacy Nix – 2013

6. Parent-Offspring Conflict and the Persistence of Pregnancy-Induced Hypertension in Modern Humans by Hollegaard B, Byars SG, Lykke J, Boomsma JJ – 2013

7. “HCG and Hyperglycosylated HCG in the Establishment and Evolution of Hemochorial Placentation.” Journal of Reproductive Immunology 82.2 by Cole, Laurence A. – 2009

8. http://en.wikipedia.org

9. http://www.ncbi.nlm.nih.gov/

10. http://nutritiondata.self.com/

11. http://www.medicinenet.com/

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4 thoughts on “The importance of a well-balanced diet during pregnancy : Micronutrients

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