Overview

Protein does more than build muscle mass. Protein is necessary to structure, function, and regulate virtually all tissues in your body. You can imagine you need protein for yourself and your growing baby during pregnancy. While there is a Recommended Daily Allowance for protein during pregnancy, some research shows the RDA is underestimated and varies based on the stage of pregnancy. Supplemental protein powders are an easy solution to add protein to your diet. There are considerations when selecting a protein powder and caution for some of the ingredients and contaminants found in some powders. This episode examines the evidence on protein requirements during pregnancy, sources of protein in animal and plant-based diets, and supplementing with protein powders.

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What is Protein?

Protein is made of amino acids and does more than build muscle mass. Protein is necessary to structure, function, and regulate virtually all tissues in your body. You can imagine you need protein for yourself and your growing baby during pregnancy.

Recommendations for Protein During Pregnancy

The recommended dietary allowance (RDA) is the average daily intake level sufficient to meet the nutrient requirements of nearly all (97%-98%) healthy people. The RDA for protein is 0.80 grams of protein for every kilogram (2.2 pounds) of body weight for someone who is not pregnant. During pregnancy, the RDA is higher to account for both your physical changes and your baby’s growth. The RDA for pregnant women is 1.1 g of protein per kg (2.2 lbs) of body weight. For an expecting mom who weighs 150 lbs (about 68 kg), the RDA is about 75 grams of protein per day. This is about an additional 21g/day over pre-pregnancy requirements.

The RDA does not consider that protein requirements increase as pregnancy progresses, with more protein required in the third trimester. One study found that the RDA for protein is underestimated. Researchers suggest the recommended protein intake increase to 1.2 grams per kilogram of body weight in the early stage of pregnancy (16 weeks) and 1.52 grams per kilogram of body weight in the late stage (36 weeks).

Protein Sources

Protein is in a variety of animal and plant foods. Animal products are considered “complete protein” because they include all nine essential amino acids your body cannot produce. Proteins from plants usually lack one or more of these amino acids. In the past, it was thought you needed to combine foods, like rice and beans, in the same meal to get complete protein. We now know this is not true, and as long as you eat a wide variety of plant-based foods, you should get all the essential amino acids. Let’s take a look at the different sources of protein.

Protein from Meat

The most accessible source of protein-rich foods is meat.

Beef

Beef is high in protein, with between 6 and 10 grams per ounce, depending on the type of beef. Overall, beef is more nutritionally dense than other meats. Beef is high in vitamin B12, one nutrient that tends to be lacking in vegetarian and vegan diets. B12 is essential for blood formation and the function of the brain and nervous system. Beef is also a good source of zinc, selenium, iron, B3, B6, and phosphorous.

Poultry and Eggs

An egg has about 6 grams of protein. Poultry, including chicken and turkey, is also high in protein. Chicken has between 5 and 9 grams of protein per ounce. Turkey has about 6 grams of protein per ounce. Chicken and turkey also have B3, B6, phosphorous, and selenium.

Pork

Pork is also a good protein source, with 4-8 grams per ounce. It also has zinc, B12, B6, niacin, iron, phosphorous, and thiamine.

Dairy

Another great source of protein is dairy, including milk, cheese, and yogurt. A vegetarian diet can include dairy, although a vegan diet does not allow animal products. A cup of milk has about 10 grams of protein. Cheese has between 2 and 6 grams of protein per ounce, depending on the type of cheese. Yogurt contains 1-1.5 grams of protein per ounce.

Organic, Grass-fed, and Antibiotics

If you consume meat or dairy during your pregnancy, you may want to consider the quality and source of the meat in your diet. Conventional factory farming utilizes antibiotics, GMO corn, and soy feed, and many concerns have been raised over the ethical treatment of these animals. Decoding labels to understand exactly what you are buying can be confusing.

Organic

For manufacturers to label meat or dairy as organic, they must meet minimum standards. Farmers must raise animals without genetic engineering, ionizing radiation, or sewage sludge. Animals must be allowed year-round access to the outdoors for at least 120 days except under specific conditions like inclement weather. Farmers must feed animals 100% certified organic vegetarian feed except for trace minerals and vitamins used to meet the animal’s nutritional requirements. Plus, animals cannot have antibiotics or added growth hormones. See this episode for more information on eating organic during pregnancy.

Antibiotics and Hormones

If you are not buying organic animal products, they could contain antibiotics and hormones. If you want to avoid meat from animals treated with antibiotics, you want to look for organic or something on the label explicitly stating that it was raised without antibiotics, no antibiotics ever, etc. Cows and sheep could be treated with hormones. If you want to avoid hormones, you can buy organic or look for a label that states hormone-free or no added hormones. Although you may see chicken or pork marketed as hormone-free, hormones are not used in these animals because they don’t have the same growth-promoting effects.

Grass-Fed

Ruminant animals like cows have a chamber in their stomach specifically designed to break down the tough cellulose structure of grass. Cows typically start in a pasture where they can eat grass. Then, the majority are moved to feedlots with a diet of grains (primarily corn and soy), which causes them to gain weight more quickly. In the United States, 88% of corn and 94% of soy are genetically modified.

While there is no difference in nutritional content between organic and non-organic, there is a difference between grass-fed and conventional beef. Grass-fed beef is higher in beta-carotene, vitamin E, antioxidants like glutathione, and omega 3s and is overall lower in fat. If you want grass-fed beef, look for a label that says 100% grass-fed. Labeling for grass-fed is confusing when you get into animals that may be grass-fed for a time but finished on grains.

Cage-free and Free-range

When shopping for poultry and eggs, the label claims can give you information about how farmers raised the animals, but you need to know what the terms mean. Cage-free eggs are fromhens not raised in cages, but it doesn’t necessarily mean they live outdoors. The criteria for the label “free-range” is that the animals have been “allowed access to the outside.”

Buying organic, grass-fed, or free-range meat can mean a significant price increase compared to conventional meat. Many nutritionists argue that the benefits of eating meat outweigh the downsides of conventional animal products. Whether buying organic, grass-fed, or no hormone-added animal products is important to you is a personal choice.

Fish

Fish are another great source of protein and are also high in omega-3s like DHA, vitamin D, and selenium. A 3-ounce portion of fish has around 14-24 g of protein. ACOG follows the FDA and EPA guidelines for fish consumption. They recommend 2-3 servings (8-12 ounces) of a variety of fish per week. They also caution against eating fish high in mercury (tilefish from the Gulf of Mexico, Swordfish, Shark, and king mackerel) and limiting albacore tuna (commonly canned tuna) to six ounces per week. There is debate over whether you can meet your nutritional requirement for DHA while limiting your fish intake. An in-depth episode on eating fish during pregnancy examines the evidence on this topic.

Farm-raised vs. Wild Fish and Seafood

There are no legal organic standards for seafood in the United States. If you see fish labeled as organic, it is likely from Northern Europe and is farmed, not wild-caught. 50% of seafood in the United States comes from farms where fish are in pens in coastal areas. Many enclosures pollute local waters with fish waste, excess feed, and antibiotics. They can also spread disease and parasites to sensitive wild marine species. If you buy salmon, fish labeled “Atlantic salmon” almost always means it is farmed raised. If you want wild-caught salmon, look for “Alaskan wild-caught” on the label.

Plant-Based Protein

People choose to eat a plant-based diet for many reasons, including environmental, ethical, or health reasons. Avoiding meat or animal products does not necessarily make a vegetarian diet healthy. Like any diet, you should focus on healthy, whole foods and limit processed foods and sugar. Although you may need to be more mindful about the nutritional content of your foods, you can get adequate protein on a plant-based diet.

If you avoid meat but are comfortable eating eggs or dairy, those are high in protein. If you avoid all dairy, other plant sources high in protein are legumes, nuts, and seeds. Beans can range anywhere from around 7-40 g of protein per cup, depending on the type of bean. Soy is 8-33 g per cup, depending on whether it is raw or cooked and the kind of soy. Half of a cup of tofu has almost 22 grams of protein. One cup of almonds is about 29 g of protein, and one cup of sunflower seeds has 23 g of protein. Nearly all foods contain some amount of protein. To find out how much protein is in a particular food, you can view a comprehensive list of protein content in foods from the USDA.

Soy

Soy has emerged as a staple in plant-based diets in recent decades, primarily because of its high protein content. However, if you eat soy regularly, you should know some of its properties. 94% of the soy grown in the United States is genetically modified. GMO crops are resistant to glyphosate, a potent herbicide; soy is high in glyphosate residues. If you want to avoid GMO soy, look for organic or non-GMO products.

Soy is high in phytic acid, which inhibits the absorption of other nutrients like calcium and iron. Lily Nichols has a great post on five reasons to avoid soy during pregnancy with links to evidence. I recommend you read it if you regularly eat soy.

Soy also contains phytoestrogens, plant-based compounds that work like estrogen in the body. You have higher estrogen levels during pregnancy than you do during your entire non-pregnant life. One study found that consumption of soy increases phytoestrogens in amniotic fluid. Other research points to phytoestrogens affecting reproductive health.

You could limit the foods you consume with soy as an ingredient or opt for fermented soy, like tempeh and natto, which aren’t processed and are easier to digest.

Protein Powder 

Regardless of your diet, protein powder is an easy solution to adding more protein. You can mix protein powder with any liquid, put it in a smoothie with other ingredients or fruit, or even mix it into yogurt or oatmeal. A wide variety of protein powders can meet your preferences if you want organic, plant-based, or other criteria. Protein powder is a supplement and should be used to supplement a well-balanced, healthy diet. This should not be your primary source of protein.

Protein Supplement Sources

Whey is the most popular source of protein powder from milk. Casein is also derived from milk but is digested and absorbed more slowly than whey. Collagen is made from bones, connective tissue, tendons, and the skin of animals. A protein powder that uses collagen peptide powder only contains 8 of the nine essential amino acids. This could be a good option if you have a dairy sensitivity. Whey, casein, and collagen are all animal-derived.

Plant-based protein powders can be a good option if you have a plant-based diet, allergy, or sensitivity to eggs or dairy. These typically use soy, pea, brown rice, or hemp protein. Some proteins use a mix of plant proteins, including chia or flax seeds, artichoke, quinoa, or alfalfa.

Ingredients in Protein Powders

Protein powders are an easy solution to adding additional protein, but you should be cautious about the protein powder you buy and how much you consume. Some ingredients or concerns you may want to pay attention to.

Many protein powders use artificial sweeteners rather than sugar. Overall, we do not see detrimental effects from non-nutritive sweeteners. Some red flags show concerns about gut microbiome health and the impact of non-nutritive or artificial sweeteners on future preferences for sweet foods. For an in-depth analysis of natural and artificial sweeteners, see this article.

Some protein powders will contain GMOs, usually from maltodextrin derived from corn. If you want to avoid GMOs, you can always opt for an organic formula or a non-GMO product.

A study by the Clean Label Project tested 134 of the top-selling protein powders and found many of them contained heavy metals like arsenic, lead, and cadmium. These are most likely from the soil ingredients are grown in. Over 50% of the products tested contained BPA, a known endocrine disruptor, likely from the packaging. Organic products, on average, had twice the amount of heavy metals than non-organic. 75% of the plant-based proteins tested positive for lead.

The protein powder you buy is largely a factor of the source of protein being within your dietary preferences and choosing a flavor you like. One resource I look to when purchasing supplements is Labdoor. This independent company tests supplements to determine whether the products have what they claim on the label and don’t contain any harmful ingredients or contaminants. You can see the rankings for protein on the Labdoor website.

Recommendations for Protein Powder

Regardless of the source of protein in a supplemental powder, they typically contain between 20 and 25 grams of protein per serving. Remember that the majority of protein should come from your diet. Supplementing with one shake a day should be fine. If you need multiple servings of protein powder to meet the protein goals, you may want to reconsider the other foods you eat.

Keeping Track of Your Diet

It can be challenging for someone who does not track their macros to know they are getting adequate protein daily. Even if you know what foods are high in protein, they contain varying amounts.

Keeping a food journal is a powerful tool for ensuring you get adequate protein. You don’t have to do this for your entire pregnancy, but keeping track of meals for a week or two is helpful to know how your diet is working. You don’t need a spreadsheet to track every single nutrient. A note on your phone or using an app may be beneficial to make sure you are getting enough protein or other vital nutrients.

Talk to Your Doctor or Midwife

In 1985, the National Research Council’s Committee on Nutrition in Medical Education recommended a minimum of 25 hours of nutrition education in medical school. This recommendation should likely be increased based on what we have learned about nutrition and diet over the past 35 years. Plus, add many years between medical school and practice; some of the learned information may be outdated. Despite the long-standing 25-hour recommendation, most medical students are not receiving adequate education in this area. According to one report that surveyed 121 medical schools in the United States, 71% do not meet the 25-hour recommendation. 36% provide less than half of that. The lack of diet and nutrition education is not just a problem in the United States. A systematic review of 24 studies found that medical students worldwide are not receiving adequate nutrition education.

Even though most schools lack sufficient education, some medical professionals independently educate themselves about diet and nutrition. Hopefully, your care provider is knowledgeable and up-to-date on nutrients, vitamins, and diet. If you have any questions about your diet or whether you are meeting the requirements for protein, please talk to your doctor or midwife. If you are not getting sufficient answers to your questions, you may need to consult a dietician or do your research to advocate for yourself.

Thank you to the amazing companies that have supported this episode.