This article was originally printed in the Natural Medicine Journal–if you would like to see the references, Click here
Especially during a first pregnancy, many women have a pronounced concern about diet: how to eat, what to eat, and when to eat. As providers, we have the opportunity to help guide them towards optimal nutrition and provide reassurance that they are making sound choices. Within the context of so many “don’ts” regarding maternal nutrition–foods to avoid because of possible bacterial contamination, mercury, lead, pesticides, nitrates, blood sugar dysregulation, insufficient or too much weight gain etc–it is good to also have some advice that helps women relax and trust their intuition. This study finds that the protein needs of women throughout pregnancy is higher than previously recommended and possibly closer to what women may be craving.
IAAO is a relatively new method that has become popular for determining protein requirements in human subjects.1-4 In the past, protein requirements were assessed by the nitrogen balance method which can be difficult because it requires that all nitrogen intake and output is carefully recorded and that the subject stays in the testing facility for the duration of the testing to measure nitrogen loss from urine, feces, saliva, and wounds. This testing takes much longer to perform and requires that subjects are put in a deficiency state for longer, which makes it unsuitable for pregnant women. For this reason, the current recommendations for protein intake during pregnancy (Estimated Average Requirement (EAR) of .88 g/kg and RDA of 1.1 g/kg) have been based on nitrogen balance studies of nonpregnant adults that have been extrapolated with total body potassium studies of protein deposition during pregnancy. 5 With the development of IAAO, researchers have been able to more accurately determine protein needs during pregnancy because they can run this study on pregnant women. Additionally, this is one of the first studies to distinguish maternal needs during early and late gestation.
Understanding protein requirements during pregnancy is important because protein is the macronutrient with the most influence on birth weight. This study assumes caloric sufficiency; for well nourished non-diabetic women, increasing protein intake is the macronutrient most likely to increase birth weight.6,7 In addition to neonatal complications and increased mortality, low birth weight is also correlated with long-term health problems such as type 2 diabetes, kidney disease, cardiovascular disease, and respiratory problems. 8-11 Ensuring that pregnant women have a protein-sufficient diet is therefore crucial for the short- and long-term health of their children.
It is important to keep in mind, however, that while this study showed protein needs to be higher than current recommendations, it is still by no means extraordinarily high. The average weight of the subjects during early pregnancy was 64.4 kilos, indicating a need for 78.6 grams of protein per day, or 314 calories. Calculated resting energy expenditures (REE) averaged 1370 calories per day, so subjects were given an average of 2329 calories (1.7 REE), putting sufficient protein consumption at 13% of calories. In late pregnancy, average weight was 71.1 kg, with a need for 108.1 grams of protein or 432 calories per day. REE was 1480, so subjects were given an average of 2516 calories, with sufficient protein consumption at 15% of calories. 13-15% of calories from protein is far lower than the recommended amounts in virtually any contemporary dietary plan save for some raw, vegan and pritikin diets which are rarely recommended or undertaken during pregnancy.
Based on these new recommendations the example below provides sufficient protein sources on average for late pregnancy with far fewer calories than necessary for a day; a pregnant woman could be encouraged to include these foods within the context of whatever other foods she prefers to meet her additional caloric needs:
Breakfast: 2 eggs, 2 slices toast=21g
Snack: One ounce of cheese=7g
Lunch: 1 cup cooked lentils with steamed veggies=18g
Snack: 2 Tbsp peanut butter on 2 rye krisp crackers=12g
Dinner: 1 cup cooked chicken breast with 1 cup quinoa and steamed veggies=51g
Total: 109g protein, approximately 1300 calories
With this in mind, practitioners may find that their patients may intuitively be eating an appropriate amount of protein: a current Canadian study found pregnant women generally eating amounts of protein more consistent with the findings of this study, rather than the current DRI.12 This assumes, of course, that women have adequate caloric intake and the financial and practical means to choose what foods they eat.
One question that is relevant to how complete the information is from the study is the possible impact of the types of food consumed rather than just macronutrient content. On the day of the study, all of the calories for the day were consumed as a shake consisting of the protein supplement which was based on an egg-white composition, kool aid or tang, and a shake base powder consisting of palm, soy, coconut and sunflower oils, corn syrup, corn starch, sucrose, calcium phosphate, sodium citrate, vitamins and minerals, plus unspecified “protein-free cookies.” This does meet the requirements of the macronutrient breakdown desired for the purpose of the research study, but certainly doesn’t resemble a dietary plan that would be advocated by most providers who would be counseling a pregnant woman. While this study certainly gives us a good baseline from which to advise patients, it is certainly within the realm of possibility that a pregnant woman’s metabolic and protein needs will shift if fiber, complex carbohydrates, and phytonutrients are present in the diet.
While it can be confusing to create an optimal diet for each individual during pregnancy, the findings from this study indicate that advising for protein intake may be a little more intuitive. For women who are adequately nourished with the financial means to choose what foods they eat, as long as they feel well enough and remember to eat some protein-containing food every few hours, they will probably be able to approximately meet their protein needs each day. For women who struggle to meet this recommendation for increased protein intake, it is important to instruct them on which foods contain protein and remind them to eat these foods every few hours. This will help to optimize the health of their baby as a newborn and throughout life.