Testing Male Fertility
December 12, 2024
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Have you ever tried googling “how much protein should I consume during pregnancy?”
Don’t do it.
It’s overwhelming and confusing and the answers range from “pregnant women need 71 grams of protein per day” to “the current RDA for pregnancy is 1.1 g per kg of body weight after the first trimester”.
Those are dramatically different answers.
And that’s why I’m here :).
Let’s dig into why protein is essential during pregnancy, how much protein you should be consuming, and what ideal sources of protein look like.
Note that I am a nutritionist, but I am not your nutritionist. The information you’ll find below is based on my own personal and clinical experience with pregnant women in my private practice.
But hey, I’d love to be your nutritionist, supporting you through fertility, pregnancy, and beyond—let’s connect and make magic!
Protein is an essential nutrient during pregnancy. Maternal nutrition during gestation, especially dietary protein intake, is a key determinant in embryonic survival, growth, and development. In simple terms – sufficient protein intake is crucial for your baby’s growth throughout pregnancy.
The amino acids that make up protein are the building blocks of your cells – and of your baby’s cells, too. Protein helps your baby develop skin, hair, fingernails, and muscles.
Additionally, the expansion of blood volume and growth of your tissues during pregnancy require substantial amounts of protein. Growth of the fetus and placenta also places additional protein demands on a pregnant mama. Thus, additional protein intake is essential for the maintenance of a successful pregnancy.
It’s crucial to get enough protein throughout all of pregnancy, but it’s especially critical during the second and third trimesters. This is the time when your baby is growing the fastest, and your body is growing substantially to accommodate your baby.
Weight loss, muscle fatigue, frequent infections, and severe fluid retention can be signs that you’re not getting enough protein in your diet.
Protein-rich foods are also naturally rich in many micronutrients required in higher amounts during pregnancy—like B12, choline, zinc, iron, and vitamin A. When you meet your protein needs (assuming you’re eating an omnivorous diet), you’re also likely to meet vitamin and mineral needs from food as well. I recommend consuming a balance of animal-sourced and plant-sourced protein as they each have unique nutritional profiles and benefits.
In addition to providing numerous micronutrients, protein is the most satiating macronutrient, meaning it helps to prevent cravings and overeating. When consumed as part of a balanced meal with carbohydrates and fat, protein improves the body’s glycemic response, since it doesn’t directly raise blood sugar but does stimulate the release of insulin … making it key for gestational diabetes management.
Even in women without gestational diabetes, getting enough protein is crucial—a protein-sufficient breakfast sets you up for a day of fewer blood sugar swings and stable energy levels, helping you thrive through pregnancy.
Want to read more about Gestational Diabetes, including how to prevent it, manage it, and find some great recipes to support you through it? Check out The Ultimate Gestational Diabetes Handbook.
Finally, sufficient protein intake is needed to support the many vascular changes that occur in pregnancy. Your body is tasked with handling about 50% increased blood volume and your entire vascular system has to adapt as a result. Sufficient protein intake, especially from amino acids found in collagen-rich foods, is key.
Meeting your daily protein needs may also lower the risk of complications like fetal growth restriction, pre-eclampsia, and preterm labor and it can help mitigate swelling in late pregnancy.
At its early stages of development, an embryo requires a great deal of cellular energy supplied by mitochondria (the “powerhouse” of the cell). In the time after the egg has been fertilized, but before it implants in the uterine wall, the embryo is extremely vulnerable to nutritional supply. When mitochondrial function is limited, we see poorer outcomes in embryo survival.
A low-protein diet has been linked to significantly less mitochondria around the cell nucleus (the “command center” that contains the DNA). As well, both low and excessively high-protein diets have been associated with a decreased number of cells inside the embryo at its blastocyst stage.
Dietary protein is important in pregnancy as the placenta requires certain levels of amino acids for proper growth and development.
Proteins are made of smaller components called amino acids. There are 20 standard amino acids, all with different functions in your body. Some protein foods contain a mix of all of them (complete proteins), while others contain only a selection (incomplete proteins). Once your body digests proteins into individual amino acids, it can rebuild new proteins within the body for various metabolic processes.
Lysine is an essential amino acid, meaning that it must be obtained in sufficient amounts from food sources for our bodies to function properly. Lysine is required for the formation of collagen, a protein that helps support and give structure to your developing baby’s skin and bones.
Low lysine intake is linked to lower immune function in mama, increased anxiety, poor GI function (oftentimes diarrhea), and a reduced ability to produce and maintain collagen (not great when you’re literally building your baby’s entire structure from your collagen stores!).
Here’s the good news: if you meet your protein needs from a variety of sources, including animal foods, you’re likely meeting your lysine requirements. Those on a vegetarian and vegan diet are at risk for insufficient lysine intake.
Foods that are richest in lysine include eggs, parmesan cheese, chicken, bacon, bison, lamb, beef, venison, turkey, pork skin, salmon, spirulina algae, and parsley.
Taurine is the most abundant amino acid in our bodies and is a “conditionally essential” amino acid, meaning the body can make plenty of it from other amino acids under normal circumstances. During pregnancy, however, taurine needs increase beyond what your body can typically supply, hence the term “conditionally essential.”
Taurine is crucial for normal fetal beta-cell development (the cells that make insulin in the pancreas), insulin action, brain development, eye development, reproduction, normal growth development, and antioxidant activity. High concentrations of taurine have also been noted in the uterine fluids of women during the luteal phase of menstrual phase (the 14 days following ovulation), suggesting that taurine may also play a role in pre-implantation embryo development.
A taurine deficiency in pregnancy may affect glucose metabolism in utero, increasing the risk of type 2 diabetes in adulthood, and has also been linked to intrauterine growth restriction.
Plasma taurine has been found to be significantly lower in women who have had gestational diabetes and there is some research showing an increased risk of gestational diabetes with low plasma taurine.
Taurine is also involved in bile acid conjugation and can increase the expression and activity of bile acid synthesis, which are key regulators of glucose, lipid and energy metabolism in pregnancy. Abnormalities of bile acid regulation in pregnancy may lead to intrahepatic cholestasis of pregnancy (ICP), a serious condition associated with several fetal and maternal morbidities. Patients with cholestasis commonly experience intense itching with associated skin lesions.
Taurine deficiency primarily affects mamas who follow a vegetarian or vegan diet—taurine is pretty much absent from most plant foods.
Foods that are highest in taurine include animal products like shellfish (like scallops and mussels), salmon, liver, dark meat from chicken, turkey, and beef, lamb, most dairy, and eggs.
Like taurine, the amino acid glycine is also “conditionally essential.” During pregnancy, however, glycine needs increase beyond what your body can typically supply, making it “conditionally indispensable.”
The only way to keep up with this demand and avoid deficiency is to obtain glycine from your diet. Glycine is an important component of collagen (making up approximately one third of collagen), and one third of all the protein in your body is made up of collagen.
Glycine turnover is incredibly high in pregnancy, both for maternal and fetal demands. Fetal DNA, bones, connective tissue, internal organs, blood vessels, everything requires glycine.
Glycine is not only important for babe, but for expecting mamas, too. Your uterus at term contains 800% more collagen than in a non-pregnant state. Your skin, which has to stretch to an unimaginable capacity, needs glycine in order to do so.
Your liver needs glycine to synthesize its major detoxification enzyme, glutathione.
And your circulatory system needs more glycine to maintain normal blood pressure and to accommodate all the extra fluids of pregnancy (this is why some research suggests it may help prevent preeclampsia).
If you want to keep your joints happy, reduce your risk of stretch marks, help your perineum stretch without tearing (or heal properly if that happens), you need to be eating an adequate amount of glycine.
Glycine also plays a key role in methylation (a biochemical process involved in a wide range of body functions, and is crucial to maintaining our overall health), much like folate, choline, and vitamin B12.
Like the aforementioned amino acids, including enough of this amino acid on a diet that excludes animal foods is challenging, since concentrations of this amino acid are generally low in plant foods. Of the plant food sources, spirulina algae is one of the best, though the quantity required to meet glycine demands is likely unfeasible.
The best way to obtain glycine in the diet is to consume the connective tissues, skin, and bones of animal foods, like you would when eating bone broth, slow-cooked meat, chicken with the skin, pork cracklings, and collagen or gelatin powder.
In some ways, proline is like glycine in that it’s not considered an essential amino acid and yet plays a vital role in pregnancy and fetal health. It tends to be found in the same foods as glycine, since it’s also a major component of collagen.
Proline is involved in differentiation of cells (including embryonic stem cells) and overall embryonic growth and development. It’s crucial for the synthesis of polyamines in the small intestine and placenta (polyamides are key regulators of DNA and protein synthesis, among other functions). Polyamine concentrations in the placenta are especially high in early pregnancy when the organ is growing rapidly (aka being formed from scratch).
Research from animal models suggests that proline is vital to fetal growth (suggesting it may play a role in intrauterine growth restriction). It also happens to be the most abundant amino acid in mammary milk (it appears to be synthesized within the mammary gland itself to further boost milk concentrations).
In general, animal proteins contain 3–6x more proline than plant proteins per gram. The richest food sources are gelatin/collagen, pork rinds, cheese (parmesan, cottage cheese, and Swiss), organ meats, cabbage, poultry, wild game, beef, and spirulina algae.
Carnitine is another “conditionally essential” amino acid in pregnancy, meaning that its synthesis from other amino acids is insufficient to meet demands. Therefore, once again, diet plays the most important role in ensuring needs are met.
Carnitine is critical for the transfer of long-chain fatty acids into the mitochondria for β-oxidation, a process that ultimately turns fatty acids into ATP (the body’s main source of energy). However, during fasting, carnitine may increase fatty acid production to ketones (a back-up energy source), which may be used by the brain for energy production under fasting conditions.
In pregnancy, the switch from fatty acid oxidation takes place more rapidly under fasting conditions than in a non-pregnant state, probably due to increased fetal demands. As a result, for the mother, carnitine is crucial to sustain energy metabolism during pregnancy.
Levels of carnitine continuously decline as pregnancy progresses and it’s important to note the research suggests inadequate iron status may impair carnitine synthesis. Low enough levels, (along with glycine) may also increase risk for gestational diabetes.
Carnitine is critical in fetal growth, and insufficiency has been linked to preterm birth (PTB), low-birthweight infants, and IUGR in the fetus. It is also essential for fetal-placental fatty acid oxidation and for the production of energy after birth in the neonate. In fact, carnitine is stored in fetal tissues in increasing amounts during the last part of gestation because babies need it to produce their own ketones for energy. Thus, maternal carnitine status is vital to ensuring an adequate supply to her baby.
Carnitine has also been found to have protective effects against lipid peroxidation (a process where free radicals interact with fatty acids in a way that results in cell damage). It also assists in the conversion of α-Linolenic acid (ALA), an omega-3 fatty acid into another form, docosahexaenoic acid (DHA), which is important for fetal brain development.
Pregnant women who are vegetarians or vegans are at risk for low carnitine since it is found exclusively in animal foods.
Foods that are highest in carnitine are red meat (like beef steak or ground beef; in fact, a general rule of thumb is “the redder the meat, the higher the concentration of carnitine”), whole milk, cheese, fish, and poultry.
Optimal protein intake is a minimum of ~100g/day (more if you’re a larger person, very active, or carrying multiples).
A good rule of thumb to remember is that you need at least 1.7 grams of protein/kg of bodyweight per day.
Let’s say you weigh 60 kilograms (132 pounds). When pregnant, your recommended daily protein intake for optimal fetal growth and development would be ~102 grams of protein per day.
Remember, as your body weight changes throughout pregnancy, your protein needs will change as well. It’s best to work alongside your medical practitioner or nutritionist to dial in the protein requirements for your body.
Remember that all animal protein sources should always be organic, grass-fed/ grass-finished, pasture raised, and/or wild caught. Purchase the highest quality you can afford and source.
This means:
Here are some of the best protein-rich, whole-foods for moms-to-be:
Chicken breast: 26 grams of protein per 3 ounces, cooked
It doesn’t take a huge portion of poultry to provide an impressive amount of protein.
Eggs: 12 grams per 2 eggs
Eggs offer up protein, plus important nutrients for pregnancy like bone-building vitamin D and the nutrient choline that supports fetal brain development.
Plain organic Greek yogurt: 17 grams of protein per 6 ounces
One single-serving cup of Greek yogurt can provide 17 grams of protein, along with calcium and vitamin B12.
Organic ground beef: 22 grams of protein per 3 ounces, cooked
Beef isn’t just an excellent source of protein — it’s also packed with iron, a nutrient that helps deliver oxygen throughout the body for both mama and baby. Bonus points if it’s made of grass-fed meat so it’s much higher in anti-inflammatory omega-3 fats.
Wild Caught Salmon: 22 grams of protein per 3 ounces, cooked
Salmon is another great source of omega-3 fatty acids for healthy development of baby’s brain, eyes, and immune system. Protein-packed fatty fish like salmon are among the best sources of these nourishing fats.
Legumes: 15 to 30 grams per cup, cooked
White, black, kidney, pinto, or navy beans and lentils, split peas or other legumes provide between 15 and 18 grams per cooked cup. Edamame is a whopping 31 grams per cup. Foods made from soybeans are another excellent source of protein: 6 ounces of tempeh has 34 grams, while 8.5 ounces of tofu offers about 20 grams of protein.
Nuts: 4 to 9 grams per 1 ounce
Peanuts, walnuts, cashews, pistachios, and almonds are all good sources of protein, with numbers ranging from 4 to 7 grams per serving (1 ounce, which is about a handful). Pumpkin seeds, sunflower seeds, chia, flax, and sesame seeds are packed with protein, offering between 5 to 9 grams per serving. And don’t forget nut butters! A serving (or two tablespoons) of peanut butter supplies 7 grams of protein.
In that first trimester, when no food sounds appetizing and everything makes you want to puke, protein powder can come in handy.
Pregnant women need increased protein for blood sugar management, minimizing nausea, placenta development, collagen production, and supporting a growing baby’s cells. High quality collagen powder is an amazing way to support all of these needs. It also supports joints, pelvic floor tissue, skin elasticity, as well as skin, hair and nail health—for both mama and baby.
Since collagen powder can be incorporated into smoothies, tea, soups, stews, oatmeal, yogurt, and other foods and beverages, it’s a convenient—and easy to consume—way to ensure adequate intake of these unique amino acids.
Lastly, collagen supports the integrity of the connective tissue during pregnancy providing a barrier of protection against diastasis and hernias. The stronger the integrity of this tissue, the healthier it will remain throughout pregnancy. And, it’s extremely helpful on a cellular level in regenerating the tissue postpartum.
This collagen product contains a unique blend of three patented collagen peptides supported by clinical research showing their efficacy for supporting collagen production, bone strength, joint health and integrity, skin elasticity, and more. It is ethically sourced from the hides of grass-fed, pasture-raised, hormone-free bovines from New Zealand.
In addition to collagen powder, I love recommending a bone-broth based protein powder to get even more protein in your diet in a delicious easy format. PurePaleo is a super clean, high quality source of bone broth-based protein, naturally rich in essential amino acids, vitamins, and minerals to support a healthy pregnancy. The highly concentrated, pure beef protein, is produced through a process that allows the protein to be hydrolyzed into peptides, resulting in easier absorption and assimilation. This protein powder contains beef from ethically-raised animals in Sweden without hormones or antibiotics, and it is non-GMO and free of grains, grasses, and/or ensilage. And the flavor is delicious – no artificial sweeteners, gums, carrageenan, or fillers. Just good ol’ vanilla beans and/or cacao powder and stevia.
Herring, C. M., Bazer, F. W., Johnson, G. A., & Wu, G. (2018). Impacts of maternal dietary protein intake on fetal survival, growth, and development. Experimental biology and medicine (Maywood, N.J.), 243(6), 525–533. https://doi.org/10.1177/1535370218758275
Institute of Medicine (US) Committee on Nutritional Status During Pregnancy and Lactation. Nutrition During Pregnancy: Part I Weight Gain: Part II Nutrient Supplements. Washington (DC): National Academies Press (US); 1990. 19, Protein and Amino Acids. https://www.ncbi.nlm.nih.gov/books/NBK235221/
Kepley JM, Bates K, Mohiuddin SS. Physiology, Maternal Changes. [Updated 2023 Mar 12]. In: StatPearls [Internet]. Treasure Island (FL): StatPearls Publishing; 2024 Jan-. https://www.ncbi.nlm.nih.gov/books/NBK539766/
Vidyadharan, V. A., Betancourt, A., Smith, C., Yallampalli, C., & Blesson, C. S. (2022). Prenatal Low-Protein Diet Affects Mitochondrial Structure and Function in the Skeletal Muscle of Adult Female Offspring. Nutrients, 14(6), 1158. https://doi.org/10.3390/nu14061158
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Sarah Jane Sandy is a certified nutrition therapist, and a fertility and women’s health expert. She has helped hundreds of women increase their fertility naturally and go on to have healthy full-term pregnancies. She has been working with women and couples trying to get pregnant for over 16 years and over 90% of the women who work with her get pregnant and have healthy babies.
She also works with women trying to fix their hormone imbalances, as well as supporting women through pregnancy and the postpartum period. Learn more about her own fertility and hormone journey here. To send Sarah a message, complete her Contact Form.
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