Everything you need to know about protein powders when pregnant or breastfeeding
Protein plays a critical role in pregnancy by supporting the growth and development of both you and your baby. Protein is needed to build your babies brain and organs, to form the placenta, to produce extra blood cells, to develop the uterus and breast tissue, and to prepare your body for delivery and breastfeeding.
As your pregnancy progresses (and your baby grows), your protein requirements increase. During the third trimester, most women require upwards of 100 g of protein/day, and this increases even further in woman who are breastfeeding. The best way to ensure you are getting enough protein is by consuming protein rich foods over the day - eggs, meat/fish/chicken, dairy, legumes, nuts, seeds, soy products. You can find lots of practical assistance with this in my book, Nurture the Seed: Your evidence-based guide to prenatal nutrition.
For those struggling to meet their protein needs through whole foods—perhaps due to nausea, food aversions, vegan/vegetarian diets, those carrying multiples, or those lacking time or energy postpartum—a protein powder may be a convenient way to meet your protein needs. But are protein powders safe in pregnancy? Which type is best? How much should you have? Let's dive in and answer all of your questions.
Are protein powders safe to use in pregnancy and when breastfeeding?
Most of the time, yes. However it depends on a few things, such as how much is used and the quality of the supplements.
Excessive protein intakes in pregnancy - Protein supplements may help reduce the risk of intrauterine growth restriction (IUGR) in undernourished pregnant women, but high amounts of protein may have adverse effects.1,2 The research is conflicting, and this is because both low and high maternal dietary protein intake cause an imbalance of amino acids, which may lead to impaired growth.3 It is reasonable to assume that if protein powders are used in excess, it may result in lower intakes of other foods and nutrients, which may have negative outcomes for mothers and babies. Therefore, moderation is key - do not rely on protein powder as your primary protein source. If you have a medical reason (such as hyperemesis gravidarum) that prevents you from eating a balanced diet, it's essential that you are getting personalised advice from a health professional.
Quality of your protein powder - Not all protein powders are created equal. Some have added ingredients or hidden chemicals that are best to avoid while you’re pregnant, for example thickeners, artificial flavourings, colourings, herbs, heavy metals, caffeine and/or sugars. Look for third-party testing or certification to ensure product safety and quality.
How much should I consume each day when pregnant or breastfeeding?
It depends on your individual needs. As a safe guide, stick to one serve/day (roughly 30 g) unless advised differently by a health care professional. You do not want protein powders to displace other foods in your diet.
Remember: You do not need to include protein powders in pregnancy or when breastfeeding, they are technically a supplement which means they are there to fill a gap in your diet. The priority should always be food.
What is the difference between whey, casein, collagen and plant-based protein powders?
Whey
Whey protein is derived from dairy milk (usually cows, but sometimes goat and sheep). Whey contains fast-digesting proteins, and is a complete protein.
Whey protein isolate (WPI): ~90% protein
Whey protein concentrate (WPC): ~80% protein
Casein
Casein protein is also derived from dairy milk, however it is a slow-digesting protein. It is a complete protein, but more expensive than whey and does not mix as well.
Casein powder: ~80-85% protein
Collagen
Collagen is a type of protein that usually comes from the connective tissue of cows (bovine) or fish (marine). It contains a mix of amino acids (it's rich in glycine), but it's not a complete protein because it lacks the amino acid tryptophan. Collagen is fast-digesting.
Collagen powder: ~95-97% protein
Plant-based
Plant-based protein powders are made from one or a mix of plant foods (often hemp, soy, pea, rice, almond, pumpkin seed, fava bean and many more). Hemp and soy are complete proteins, but most other plant-based protein powders are not. Plant-based protein powders are slow-digesting, and absorption isn't as high as animal based protein.
Hemp: ~60-65% protein
Soy: ~80-90% protein
Brown rice: ~85% protein
Pea: ~80-85% protein
What type of protein powder is best?
This will depend on your individual needs, your taste preferences and your values. WPI is often tooted as the "best" form because it is a complete protein, is absorbed well and mixes into food easily. However, if you zoom out and look at your diet as a whole, the form of protein may not make a big difference.
What about collagen?
Collagen is a structural protein made up largely of the amino acid glycine. It's a key component of our skin, bones, tendons and cartilage, providing strength and elasticity. Glycine requirements increase in pregnancy because it is required to grow your placenta, breast tissue and stretching skin, and to increase your blood volume. Some research suggests that glycine should be considered a "conditionally" indispensable amino acid during the third trimester.4 Glycine remains important postpartum when your tissues are repairing themselves.
You can meet your increased glycine requirements by regularly eating foods that are rich in collagen - bone broth, meat on the bone (eg. osso bucco), meat with connective tissue (eg. shoulder, brisket), or eating the skin of chicken and fish. If you don't eat these foods regularly, a collagen or gelatin supplement may be of benefit to you. You can read more about collagen in pregnancy/postpartum in this Instagram post.
Why do some protein powders upset my tummy?
Many people report feelings of an upset tummy - constipation, diarrhoea, bloating, gas, abdominal pain - with the use of protein powders. There are many reasons these symptoms might occur, here are the most common:
Sweeteners, gums and thickeners - These added ingredients don't agree with everyone. Erythritol, sorbitol or xylitol are often the worst culprits (these are sweeteners). Try a powder without added sweeteners, gums and thickeners and see if your symptoms improve.
Lactose intolerance - Whey and casein protein powders contain lactose, which can cause bloating and gas in people who are lactose intolerant. Try whey protein isolate (WPI) which is lower in lactose, or switch to a plant-based protein powder if you think this is the case for you.
Consuming protein powder without food - If protein powder mixed with water is giving you an upset stomach, blend it with some fruit, milk, yoghurt, nut butter etc so that it's not as harsh on your digestive system.
Going too hard too soon - Start with half of the recommended serve in your smoothie and gradually work your way up. Don't consume more than one serve/day unless advised by your health care provider. Overdoing protein powder may displace other foods in your diet.
What ingredients should I consider when choosing a protein powder?
This will again depend on your individual circumstances - your diet, your taste preferences, your budget and your values.
I tend to opt for protein powders without any added ingredients. For example, unflavoured whey protein, pure plant protein or collagen powder (a small amount of soy or sunflower lecithin is sometimes added to help with mixing, which is fine - it's usually only 0.2 %). These powders act as a protein supplement without fillers, gums, or artificial sweeteners/flavours. You can then flavour your food as you usually would, and being unflavoured, you can use them in sweet foods (smoothies, porridge, baking) or savoury foods (soups, dahl, curries).
In saying this, some people prefer the taste of protein powders that have added sweeteners and flavours, and this is completely fine. This may be particularly helpful for those with gestational diabetes, because the flavoured protein powders provide sweetness to foods without adding sugar/carbohydrates. Try to stick to natural sweeteners, like monk fruit, stevia or vanilla beans. As I mentioned above, erythritol, sorbitol and xylitol often contribute to gut upset. And, it probably goes without saying, but steer clear of protein powders with caffeine if you are pregnant or breastfeeding (unless it fits within your daily total of < 200 mg caffeine/day).
You may also find ingredients like coconut milk powder, MCT oil, probiotics, maca, psyllium husk, chia seeds or salt. These ingredients are fine if you like the taste of the protein powder. However don't rely on a protein powder for fibre or probiotics (aim to get these through your diet - learn how in my book, Nurture the Seed).
You may also like to consider where the protein was sourced. If it's important to you, choose Australian products from animals that are grass fed, or products that are made from organic ingredients.
What about protein powders with added vitamins?
Some protein powders are fortified with additional vitamins and minerals, such as calcium, iron, vitamin D and folic acid. As a general rule, I don't recommend these unless you have been advised to take them by your health care provider. Some woman accidently end up “double dipping” when taking these types of protein powders alongside a prenatal multivitamin. This could lead to toxicity of some nutrients, or it may prevent other nutrients from being absorbed.
How to incorporate protein powder into your diet
If you've been advised to use a protein powder (or think you would benefit from a boost of protein), here are some ways to include it:
Smoothies
Chia pudding
Overnight oats
Porridge
Baking
Stirred into yogurt
Soups and Dahl (use unflavoured protein powders or collagen)
Hot chocolate or coffee
You may like these recipes:
Green coconut smoothie here
Take home message
Protein powders are generally safe for pregnant and breastfeeding women and can be useful for those who struggle to meet their increased protein needs through diet alone. However, it’s best for the majority of your protein intake to come from whole foods, which provide additional essential nutrients for you and your baby. If symptoms such as nausea or food aversions make it difficult to maintain a balanced diet, consult your healthcare provider for guidance on meeting your nutritional needs.
Disclaimer
The information in this blog is for educational purposes only. It is not intended to replace medical or personalised nutrition advice.
References:
Say L, Gülmezoglu AM, Hofmeyr GJ. Maternal nutrient supplementation for suspected impaired fetal growth. Cochrane Database Syst Rev. 2003;(1):CD000148. doi: 10.1002/14651858.CD000148. PMID: 12535390.
Brown LD, Green AS, Limesand SW, Rozance PJ. Maternal amino acid supplementation for intrauterine growth restriction. Front Biosci (Schol Ed). 2011 Jan 1;3(2):428-44. doi: 10.2741/s162. PMID: 21196387; PMCID: PMC3181118.
Herring CM, Bazer FW, Johnson GA, Wu G. Impacts of maternal dietary protein intake on fetal survival, growth, and development. Exp Biol Med (Maywood). 2018 Mar;243(6):525-533. doi: 10.1177/1535370218758275. Epub 2018 Feb 22. PMID: 29466875; PMCID: PMC5882021.
Rasmussen BF, Ennis MA, Dyer RA, Lim K, Elango R. Glycine, a Dispensable Amino Acid, Is Conditionally Indispensable in Late Stages of Human Pregnancy. J Nutr. 2021 Feb 1;151(2):361-369. doi: 10.1093/jn/nxaa263. PMID: 32939556; PMCID: PMC7850138.
