Egg quality is crucial for optimal fertility. Infertility is defined as an inability to conceive after 12 months of unprotected, appropriately timed intercourse. (1) There are many factors that can lead to infertility including maternal age, chronic diseases, exposure to environmental toxins, ovulatory dysfunction, reproductive disorders; all of these may lead to diminished egg quality and quantity. (1)
Many women worry about egg numbers (tested by a blood test called "anti mullerian hormone" or AMH). While egg numbers are important, but egg quality is equally if not more important. The good news is you can improve egg quality. It takes around 100 days for develop an egg follicle, so 3 months of knuckling down for preconception care can make a huge difference.
This article will discuss nutrients that have demonstrated positive clinical research indicating their efficacy at improving egg (oocyte) quality, often whilst patients are undergoing assisted reproductive technology (ART); thus, enhancing effectiveness of treatment and ultimately fertility.
Ovarian response (OR) to stimulation in ART is pivotal in predicting the success of the treatment. Poor ovarian response (POR) where oocyte development is fewer, means reduced embryo numbers for cryopreservation or transfer; this may undermine pregnancy success. (2)
CO-ENZYME Q10
Co-enzyme Q10 (CoQ10) is a fat-soluble nutrient that protects DNA and lipids from oxidation, making it a potent antioxidant vital for egg health. (3) Oxidative stress along with dysfunctional mitochondria (mitochondria are responsible for cellular energy production) are thought to be determining factors in OR.
A recent study on 169 young women with POR who were undergoing ART treatment (either in vitro fertilisation [IVF] or intracytoplasmic sperm injection) demonstrated the importance of CoQ10. Women treated with CoQ10 required significantly less gonadotrophin in order to stimulate ovaries. Administration with CoQ10 yielded higher numbers of retrieved oocytes, increased fertilisation rates and significantly higher quality embryos, compared to controls. Cancelled embryo transfer as a result of poor embryo growth was significantly less in the CoQ10 group compared to controls (8.33% vs. 22.89%). Women in the intervention group also had more cryopreserved embryos available compared to controls (18.42% vs. 4.3%). Lastly, the number of live births and clinical pregnancies were higher in women administered with CoQ10 however, results were not significant. (3)
A study demonstrated that in older women (aged 38-46 years) undergoing IVF, CoQ10 administration significantly enhanced oocyte maturation (82.6% vs. 63.0% in controls) and reduced oocyte chromosomal abnormality rates (36.8% vs. 65.5% in controls). No differences were seen in younger women aged under 30 years. (4)
Oocyte ageing, which occurs if fertilisation doesn’t occur within the optimal time-window after ovulation, is another factor that impedes effectiveness of ART. (5) A recent in-vitro mice study, demonstrated that CoQ10 can reduce the post-ovulatory ageing- induced quality deterioration of oocytes and improved maturation of post-ovulatory aged oocytes. CoQ10 suppressed ageing-induced oxidative stress of oocytes, by inhibiting superoxide (a free radical) and stopping apoptosis (cell death). (5)
BENEFITS OF COQ10 :
- Reduced requirements of gonadotrophin hormone for ovarian stimulation
- Higher oocyte retrieval numbers
- Increased fertilisation rates
- Lower rates of cancelled embryo transfer
- Greater embryo quality
- Enhanced availability of cryopreserved embryos
FOODS RICH IN COQ10:
- Highest concentration in organ meats including liver, heart, kidney (always ensure you purchase organic!)
- Fatty fish including herring, sardines and mackerel
- Cruciferous vegetables like cauliflower and broccoli and leafy greens like spinach
- Grass-fed butter
- Nuts/seeds (Particularly walnuts, hazelnuts, sesame seeds-tahini, peanuts)
- Fruit: oranges and strawberries
ZINC
Zinc is also an important mineral needed for egg health. An in-vitro mice model demonstrated the difference in oocyte development in a zinc-deprived culture medium vs. a model containing normal levels of zinc. (6) Oocytes were collected from pre-antral ovarian follicles. This pre-antral oocyte development phase in humans lasts between 3-5 months and occurs before the follicles are ready to ovulate, hence 3 months minimum preconception care required to see benefits. On day 4, zinc deprived oocytes were significantly smaller than the control group and the zinc containing group along with having disrupted nuclear development. Zinc deficiency hindered cultured oocyte meiosis (cell division). Interestingly, even after the zinc-deficiency oocytes were transferred into the zinc containing culture medium, meiosis was disrupted; thus stressing the importance of zinc in the pre-antral phase of oocyte development. (6)
What is the pre-antral phase? It's the first phase of egg (oocyte) growth and differentiation. If the oocyte doesn't develop properly it is not released, leading to infertility.
BENEFITS OF ZINC:
- Assists oocyte growth and development in the early (pre-antral) phase
- Necessary for proper nuclear maturation
- Assists proper oocyte meiosis (cellular division)
- Infers the importance of pre-natal zinc supplementation for proper oocyte maturation
ZINC RICH FOODS:
- Oysters
- Eggs
- Nuts and seeds
- Red meat (organic is preferable!)
- Legumes
VITAMIN D
One observational study on 1232 couples that were undergoing IVF treatments analysed the relationship between circulating 25-hydroxyvitaminD (vitamin D) levels and fertility rates. (7) Serum vitamin D levels in women were separated into Group A (less than 10%), B (between 10-90%) and C (greater than 90%). There was a positive correlation between fertility rates and vitamin D levels in women, with fertility rates being 59.50% in Group A, 62.72% in Group B, and 66.13% in Group C. However, male vitamin D levels were not correlated with low fertilisation rates. (7)
Another study supported the above correlation between fertility rates and serum vitamin D levels, this time in randomly selected women who were going through ART. (8) This positive relationship however did not translate into higher pregnancies and live births. (8)
The positive correlation between sufficient vitamin D status and the translation to clinical pregnancies from ART was demonstrated nevertheless in an earlier 2010 study. (9) Higher vitamin D serum levels and follicular fluid levels were associated with a significant increase in the likelihood of a clinical pregnancy after IVF–embryo transfer. (9)
A very interesting 2014 study suggests that vitamin D’s effect on fertility may actually stem from the endometrium’s need for vitamin D rather than the oocyte/egg. (10) This was discovered by involving 99 oocyte donor-recipient couples and testing the donor serum vitamin D levels prior to the embryo transfer and recipient serum levels. It was found that clinical pregnancy rates were fewer among vitamin D-deficient recipients compared to vitamin D-replete recipients (37% vs. 78%). Live-birth rates were 31% in vitamin D-deficient recipients vs. 59% in vitamin D-replete recipients. This suggests the importance of vitamin D for the endometrium rather than early oocyte development. (10)
VITAMIN D BENEFITS:
- Importance of normal maternal vitamin D levels for fertility
- Positive relationship between normal vitamin D levels and fertility rates
- Low vitamin D levels was a risk factor for low fertility rates
- Sufficient vitamin D levels may be associated with a greater chance of clinical pregnancy after ART therapy
- Vitamin D seems to be necessary for the endometrium in pregnancy
VITAMIN D SOURCES:
- Mainly synthesised through sunlight exposure. Ensure 20 minutes per day of full sun exposure to maintain levels.
- Vitamin D3 (cholecalciferol) rich foods are animal-based products and include eggs, fatty fish, grass-fed butter and dairy products and cod liver oil.
- The other form of vitamin D is vitamin D2 (ergocalciferol) which is found in plants like fungi/ mushrooms.
Handy tip: Levels of Vitamin D increase in mushrooms when you place them in the sunshine, “gill” side up for at least 15 minutes prior to eating them.
Watch this space for Nutrition for Egg Quality: Part 2 coming soon.
This blog was put together with the help of Annabel Murray, who i currently doing an online internship with me. You can follow her on instagram @inadayjournal
References
1. Vitale SG, Rossetti P, Corrado F, Rapisarda AMC, La Vignera S, Condorelli RA, et al. How to achieve high-quality oocytes? The key role of myo-inositol and melatonin. Int J Endocrinol [Internet]. 2016 Aug 29;1–9. doi:10.1155/2016/4987436
2. Esteves SC, Roque M, Bedoschi GM, Conforti A, Humaidan P, Alviggi C. Defining low prognosis patients undergoing assisted reproductive technology: POSEIDON criteria—The why. Frontiers in Endocrinology [Internet]. 2018 Aug;1(9). doi:10.3389/fendo.2018.00461
3. Xu Y, Nisenblat V, Lu C, Li R, Qiao J, Zhen X, Wang S. Pretreatment with coenzyme Q10 improves ovarian response and embryo quality in low-prognosis young women with decreased ovarian reserve: A randomized controlled trial. Reprod Biol Endocrinol. 2018;16(29). doi:10.1186/s12958-018-0343-0
4. Ma L, Cai L, Hu M, Wang J, Xie J, Xing Y, et al. Coenzyme Q10 supplementation of human oocyte in vitro maturation reduces postmeiotic aneuploidies. Fertility and Sterility [Internet]. 2020 Aug;114(2):331–7. doi:10.1016/j.fertnstert.2020.04.002
5. Zhang M, ShiYang X, Zhang Y, Miao Y, Chen Y, Cui Z, et al. Coenzyme Q10 ameliorates the quality of postovulatory aged oocytes by suppressing DNA damage and apoptosis. Free Radi Biol Med [Internet]. 2019 Nov;143:84–94. doi:10.1016/j.freeradbiomed.2019.08.002
6. Hester JM, Diaz F. Growing oocytes need zinc: Zinc deficiency in the preantral ovarian follicle. FASEB J. 2018 April;32(S1). doi: 10.1096/fasebj.2018.32.1_supplement.882.1
7. Jiang L, Yang J, Song J, Hu Y, Qian K. Normal fertilisation rates and serum 25-OHD levels among couples undergoing in-vitro fertilisation: A prospective cohort study. BMC Pregnancy Childbirth. 2020 June;20(1). doi:10.1186/s12884-020-02959-z
8. Abadia L, Gaskins AJ, Chiu Y-H, Williams PL, Keller M, Wright DL, et al. Serum 25-hydroxyvitamin D concentrations and treatment outcomes of women undergoing assisted reproduction. AM J CLIN NUTR [Internet]. 2016 Sep;104(3):729–35. doi:10.1007/s00404-013-2959-9
9. Ozkan S, Jindal S, Greenseid K, Shu J, Zeitlian G, Hickmon C, et al. Replete vitamin D stores predict reproductive success following in vitro fertilization. Fertility and Sterility [Internet]. 2010 Jan;94(4):1314–9. doi:10.1016/j.fertnstert.2009.05.019
10. Rudick BJ, Ingles SA, Chung K, Stanczyk FZ, Paulson RJ, Bendikson KA. Influence of vitamin D levels on in vitro fertilization outcomes in donor-recipient cycles. Fertility and Sterility [Internet]. 2014 Feb;101(2):447–52. doi:10.1016/j.fertnstert.2013.10.008