Dietary Strategies to Support Ovulatory Function (Part 2): Animal vs. Vegetable Protein
Ovulatory function is a critical component to conception and fertility. When ovulation is affected and the prominent follicle in the ovary fails to rupture, the chance of conception during that cycle is lost.
The thing about ovulatory dysfunction is that it can occur in many cases without any obvious signs or changes in the menstrual cycle. In the most obvious cases, such as polycystic ovarian syndrome, there can be some very clear signs that ovulation is not occurring. An example of some of these signs is the absence of a menstrual cycle or extremely long menstrual cycles, and/or increased hair growth on the face, chin, back, abdomen, etc. However, for some Women with ovulatory dysfunction there can be a what appears to be a normal menstrual cycle (i.e. a 28-30 day cycle with regular menstrual flow), but in fact there is an absence of ovulation. These cases can fall in to what is called estrogen breakthrough or estrogen withdrawal bleeds, meaning, that the menstrual flow that occurs is not due to declining progesterone levels that should normally occur in a cycle where the ovulated egg is not fertilized, but rather due to an excess of estrogen or declining levels of estrogen. In fact, some Women can have these "normal-appearing cycles" while trying to conceive for months when in fact they are not ovulating during those cycles.
Animal Protein versus Vegetable Protein
High protein diets have an established role in supporting insulin regulation for Women with PCOS, and therefore supporting ovulation and fertility. However, there is a lack of research surrounding the ideal types of protein to support ovulatory function.
A retrospective cohort study on Women with infertility resulting from ovulatory dysfunction found that substituting even 5% of your total daily caloric consumption from meat protein to vegetable protein may decrease the risk of ovulatory dysfunction by more than 50%. The group with the highest meat protein consumption was observed to have approximately a 39% increased relative risk for ovulatory dysfunction and the group of Women with the highest vegetable protein intake was found to have an approximate 22% decreased risk of ovulatory dysfunction.
The researchers concluded that replacing animal sources of protein with vegetable sources of protein may have a protective effect on ovulation and decrease risk of ovulatory dysfunction.
Why the Difference?
The researchers mentioned that other studies have found that vegetable protein may induce a lower insulin response in the body when compared to animal protein. The increased levels of insulin in the blood may explain the higher rates of ovulatory dysfunction.
Another reason postulated by the researchers was that meat protein may increase hormone levels of Insulin-like growth factor-1 (IGF-1), which may contribute to the development of PCOS. Vegetable protein does not appear to have any correlation with levels of IGF-1.
The study was a retrospective cohort study, and these studies are unable to establish a certain cause-effect relationship. However, a balanced diet that includes healthy amounts of vegetable protein appears to be protective. A strategy to include more vegetable protein in your diet could be as easy as a greens protein powder to substitute meat protein during one of your meals.
This article is in no way a replacement for medical advice or medical care, it is advised that anyone concerned about their Health should speak with their Naturopathic Doctor or Primary Care Provider.
1. Chavarro JE, Rich-Edwards JW, Rosner BA, et al. Protein intake and ovulatory infertility. Am J Obstet Gynecol 2008;198:210.