Protein Intake for Pregnant Women

by Loren Cordain, Ph.D., Professor

Q: Hello Dr. Cordain

I would like to know if you could direct me to any research that indicates what amounts of protein are necessary for pregnant women who live the Paleo Diet way. I am in my third trimester with my first child and have been living Paleo since I first heard you lecture on it back at Boulderfest before your book came out. I have been the picture of health and my pregnancy has been very easy. I am finding that my protein and fat requirements are significantly higher.

Is there any research you could direct me to regarding protein requirements for pregnancy based on trimester?

Thank you very much and I look forward to hearing from you.

Best Regards,
Lynda

A: Hi Lynda,

This question has come up before and the bottom line is that your probably should increase your fat and carbohydrate consumption, and limit protein to about 20-25% of energy, as higher protein intakes than this may prove to be deleterious to mother and fetus for a variety of physiological reasons. In my next book, I have devoted a chapter to maternal nutrition before, during and after pregnancy and why protein must be limited during pregnancy.

My colleague John Speth (an anthropologist) at the University of Michigan wrote a paper on protein aversion in hunter-gatherer women during pregnancy. Listed below is the abstract: (note the 25% protein energy ceiling!!!)

"During seasonal or inter-annual periods of food shortage and restricted total calorie intake, ethnographically and ethnohistorically documented human foragers, when possible, under-utilize foods that are high in protein, such as lean meat, in favour of foods with higher lipid or carbohydrate content. Nutritional studies suggest that one reason for this behaviour stems from the fact that pregnant women, particularly at times when their total calorie intake is marginal, may be constrained in the amount of energy they can safely derive from protein sources to levels below about 25% of total calories. Protein intakes above this threshold may affect pregnancy outcome through decreased mass at birth and increased perinatal morbidity and mortality. This paper briefly outlines the evidence for the existence of an upper safe limit to total protein intake in pregnancy, and then discusses several facets of the issue that remain poorly understood. The paper ends by raising two basic questions directed especially toward specialists in primate and human nutrition: is this protein threshold real and demographically significant in modern human foraging populations? If so, does an analogous threshold affect pregnant female chimpanzees? If the answer to both of these questions is yes, we can then begin to explore systematically the consequences such a threshold might have for the diet and behaviour of early hominids."2

The physiological basis for this aversion stems from a reduced rate of urea synthesis during pregnancy that is evident in early gestation1 as well as increases in the stress hormone cortisol3. Hence, pregnant women should include more carbohydrate and fat (i.e. fattier meats) in their diets and limit dietary protein to no more than 20-25% of their total caloric intake.

Hope this helps!
Loren Cordain, Ph.D., Professor

References:
Kalhan, S. Protein metabolism in pregnancy. Am J Clin Nutr 2000;71 (suppl): 1249S-55S.Speth JD. Protein selection and avoidance strategies of contemporary and ancestral foragers: unresolved issues. Philos Trans R Soc Lond B Biol Sci. 1991 Nov 29;334(1270):265-9; discussion 269-70.Herrick, K., Phillips, D. I. W., Haselden, S., Shiell, A. W., Campbell-Brown, M., Godfrey, K. M., 2003. Maternal consumption of a high-meat, low-carbohydrate diet in late pregnancy: relation to adult cortisol concentrations in the offspring. J. Clin. Endocrinol. Metab. 88(8):3554-3560.

Paleo Diet Q & A - Whey Protein

Q: Could you please provide some details on the benefits/detriments of whey protein supplementation? I am a weight trainer/powerlifter and supplement with whey protein, which is currently touted as the best/most health-conscious choice there is. I have read in your newsletter about the inflammatory aspects of dairy products - is whey protein included in this? Is it better or worse than other dairy products?

Many people interested in the Paleo Diet who are also into strength training and fitness would be interested in your thoughts on this. Any pointers re: inflammation and supplementation of protein would be very well received. Thank you, in advance.

Best regards,
Karl

A: Dear Karl,

Unfortunately, at this point, most of the research has focused on the beneficial effects of whey. It basically revolves around whey's high BCAA content, its use as a post-workout recovery drink ingredient, and its capacity – due to cysteine – to increase Glutathione, a powerful endogenous antioxidant enzyme.

Nevertheless, we believe that whey protein can have some potential adverse effects, because it greatly elevates insulinemia - although it can be therapeutic for diabetics in the short term. We suspect that whey protein could be detrimental long term, as hyperinsulinemia can down-regulate the insulin receptor and lead to insulin resistance. Insulin resistance underlies the Metabolic Syndrome, and is implicated in various other diseases, such as Acne, Alzheimer, various cancers, Coronary Heart Disease, Myopia, PCOS, etc.).

But to be completely sure, we would need intervention studies with whey protein with a relatively long duration in people genetically prone to insulin resistance, or who are in fact insulin resistant.



Also, there is the matter of hormones in milk: estrogens, DHT precursors, Insulin, IGF-1 and the hormone Betacellulin (BTC), which Dr. Cordain has discussed in a previous edition of this newsletter. These are some of the possible mechanisms for which there is repeated epidemiological evidence associating milk consumption with some cancers - especially Prostate Cancer.

We know that these hormones are present in milk and - in the case of BTC - it is present in whey too. Nevertheless, the real content of all these hormones in commercial milk-derived products is an open question that deserves proper and urgent study. So while we don’t know for sure, and since and we have alternatives, I would follow the old saying: do no harm!

Finally, if you have an auto-immune disease or allergy to Beta Lacto Globulin (protein that exists in bovine milk, but nonexistent in human milk) I would stay away from whey. Whey contains not only Beta Lacto Globulin, but also Bovine Serum Albumin. Some peptides from this protein have structural homology with peptides from our own tissues, and BSA has been implicated in Multiple Sclerosis, Rheumatoid Arthritis and Type 1 Diabetes.

In conclusion, I would follow the evolutionary template until all these issues are resolved. which states that recently introduced foods may have potential adverse effects to humans, especially long term. Non-human milk was only introduced in the human diet ~10,000 years ago. Therefore, given the potential health hazards of milk that science is revealing, I would use another protein source. Lean meat and seafood are very good sources of BCAA. If you want a protein drink immediately after strength training to speed recovery and increase muscle mass, I would suggest ~9 grams of essential amino acids, along with a banana.

I hope this helps.

Cordially,
Pedro Bastos

Editor's note: the following blog posts also discuss whey protein:
Q: I started the program and I was wondering if Whey Protein or protein powder in general is against the diet?
Q: I like drinking protein shakes in the morning, but I noticed some of the protein sources in my protein shake are made from milk or dairy products. Is there an alternative that is available in the market place?
Q: I am just trying to figure out your feelings and thoughts on protein powders.
Additional reading: Hyperinsulinemic diseases: more than just Syndrome X.