GESTATIONAL NUTRITION
Doing the math for a healthy pregnancy and a healthy baby
By Carisa Paraz, MD, Contributing Writer
"I eat for two, walk for two, breathe for two now." -10,000 Maniacs, 'Eat for Two'
If eating for one is so enjoyable, one can assume that eating for two is joy multiplied. This is hardly the case though. A Food and Nutrition Research Institute (FNRI) survey in 1998 showed that pregnant Filipino women only consume 72.5 percent of the recommended daily allowance (RDA) for calories, 86.2 percent for protein, and a minuscule 25 percent for iron. This is alarming, considering how maternal nutrition has long been linked to the course and outcome of pregnancy.
Pregnancy weight gain plays a major role in fetal growth. Inadequate weight gain during the latter half of pregnancy predicts poor pregnancy outcomes. Maternal prepregnant weight can also have adverse effects on the pregnancy. An underweight woman has an increased risk of delivering prematurely, or giving birth to an infant that is small for gestational age. On the other hand, obesity has been associated with gestational diabetes, preeclampsia, fetal macrosomia, and caesarean delivery. The risk of early neonatal death is also increased twofold and of late fetal death by three to four times.
Because of its many consequences, maternal nutrition is, to Dr. Emilie Flores, "an investment of a lifetime." It is a subject close to her heart, given that she's been a nutrition professor at the University of the Philippines College of Public Health for 20 years now.
Considering the adverse effects of maternal under- or overweight, nutrition can play a key role in controlling weight gain in pregnancy. Underweight pregnant women have to gain 12.5 to 18 kilograms during pregnancy, compared with the normal recommended weight gain of 11.5 to 16 kilos. Pregnant obese women, on the other hand, have to keep their weight gain below six kilograms.
Weight gain by the mother is attributed to weight gain by the fetus, but this is not always the case. Says Flores: "In an underweight pregnant woman, for every one-kilogram increase in her weight, there is a corresponding increase in the weight of the baby by 45 grams." For every one-kilogram increase in a normal-weight mother, the baby's weight increases by 25 grams. However, in obese pregnant women, the corresponding increase is only 12 grams. "This means na mas maraming napupunta sa weight ng nanay kaysa baby," explains Flores, who holds a PhD in nutrition.
Establishing energy requirements
Although there are established RDAs for pregnancy, it is best to determine daily caloric needs or total energy requirement (TER) individually.
To compute the TER, the desirable body weight (DBW) is first obtained using Tanhausser's Method:
DBW = (height in cm-100) - 10% (height in cm-100)
The DBW is then multiplied by a factor depending on one's daily energy expenditure:
Physical Activity (calories/kg/day)
Sedentary (mostly sitting) 30
Light (tailor, nurse, physician, jeepney driver) 35
Moderate (carpenter, painter) 40
Strenuous (athlete, lumberman) 45
Depending on the diet prescription or eating habits of the person, the TER is divided among carbohydrates, proteins, and fats as follows:
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Carbohydrates: 55 to 65 percent
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Proteins: 10 to 15 percent
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Fats: 20 to 35 percent (after fulfilling the carbohydrate and protein requirements, the remaining calories are allotted to fat)
How does one's TER change with pregnancy?
First trimester
During the first trimester, the pregnant woman has to add 100 to 150 calories to her TER. This is easily done by eating an extra one-half to three-fourths cup of rice a day. Proteins and amino acids, particularly arginine and lysine, are important in the maintenance and survival of the embryo. These two amino acids are among the basic needs of a fetus. Daily protein intake should be equivalent to nine grams plus one gram per kilogram of body weight. A simpler way of assuring adequate protein intake is allotting 20 percent of TER to protein.
Zinc, selenium, iodine, and folate are also important. If these minerals are not taken in adequate amounts, the baby is at risk of developing a neural-tube defect (NTD). Although folate is recommended to be taken as early as three months prior to conception to prevent NTDs, Flores explains: "Folate does not work alone; it needs other elements."
Second trimester
A pregnant woman usually starts "showing" after her first trimester. This growth corresponds to additional calories. During this time, her protein requirement stays the same as the first trimester, but she needs to add an extra 300 calories per day to her total requirement.
Iron supplementation is usually recommended starting the second trimester because the blood volume expands at this time and iron becomes relatively scarce. This phenomenon is called the "physiologic anemia of pregnancy." As a response, the body increases its iron absorption by 40 percent starting on the fourth month. Calcium absorption also doubles toward the end of the second trimester while folate uptake increases by 33 percent for growth of the uterus and the fetus. Iodine and zinc are also needed for normal metabolism and growth.
Third trimester
A pregnant woman still needs an additional 300 calories per day in her third trimester. However, a larger percentage of this will come from proteins, as her daily protein requirement is raised to 15 grams plus one gram per kilogram of body weight. The daily calcium requirement is increased to 1,000 to 1,500 mg (from a nonpregnant RDA of 500 mg) to accommodate fetal-bone growth and to get ready for the demands of lactation. To fulfill the additional 300 calories for the second and third trimesters, Flores suggests having a cup of corn kernels for morning snack, two pieces boiled saba for afternoon snack, and two cookies for bedtime snack.
What to eat
Although supplements for pregnant women are abundant in the market, following a healthy, balanced diet will ensure that her nutritional requirements are adequately met. Flores recommends the following foods that are rich in energy, proteins, and essential fatty acids:
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Carbohydrates: Rice, corn, root crops, vegetable oils, grains, nuts;
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Proteins: Milk, cheese, eggs, poultry, liver, meat, legumes.
Meanwhile, these foods are rich in water- and fat-soluble vitamins, and minerals:
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Dark green, leafy vegetables and yellow fruits and vegetables: ex. carrots, spinach, alugbati, malunggay, camote tops, ampalaya tops;
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Seafood, liver, eggs, seaweeds (such as latô, which is a very good source of iodine).
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