A new study shows that zinc deficiency can negatively affect the early stages of egg development, reducing the ability of the egg cells to divide and be fertilised. This may affect fertility “months” in the future and why preconception planning is so important for a couple. The researchers will be presenting their results at the American Physiological Society annual meeting at Experimental Biology 2018 in San Diego.
Millions of couples around the world struggle with fertility issues and the ability to conceive a child. While there are many factors that can make conception difficult, ovulation disorders and sperm issues are a leading cause of couples not being able to conceive. Researchers are finally looking into how vitamins, amino acids and micronutrients affect fertility and in particular the early stages of egg development.
The availability of micronutrients, through diet, amino acids, antioxidants and vitamin supplements, in the ovarian environment and their influence on the development, viability and quality of egg cells is now the focus of a growing area of research. Sperm also need micronutrients, antioxidants, vitamins and nutrients for optimal growth and development too. This is nothing new to me as this is something I have always focussed on for many years as part my fertility program and as a part of preconception planning and making sure that the couple are in optimal health before trying to conceive.
In human and mammals, the ovary is made up of thousands of structures called follicles, which consist of one oocyte surrounded by layers of support cells, known as somatic cells. At puberty, the body starts to prepare groups of oocytes for maturation, ovulation and fertilization. While a female grows groups of oocytes, which begin to mature each month, only one will be ovulated and have the chance of being fertilized. Many things can influence whether an oocyte will mature correctly and the go on to one day be ovulated, including the presence of sufficient levels of certain micronutrients. To date this has probably been poorly understood by many.
Scientists have recently found more and more evidence to show that zinc is a key player in oocyte development and have been assessing the effects of zinc on egg development extremely early on in the development and maturation of oocytes.
Previously Fertility research and treatment has primarily focused on the larger follicles, called antral follicles, which respond to signals from the pituitary gland to be ovulated. In humans, preantral follicles have to keep growing for about 90 days before they are ready to ovulate. This is why it is important to focus on egg and sperm quality months before conception is to take place, because this is when both egg and sperm are still growing and maturing and need vital nutrients to develop properly.
In this new research they have examined the smaller preantral follicles, which are still growing and don’t respond to the ovulatory signal yet. Previous studies showed that zinc levels are critical in the antral follicle, but no one had tested the effect of zinc deficiency on preantral follicle growth.
The researchers collected preantral follicles and then matured them in a special cell culture medium. They compared eggs matured in a zinc deficient environment to those grown with normal levels of zinc. The researchers found that preantral zinc deficiency:
- Impaired the egg cell’s ability to properly divide (meiosis), which is a necessary step before successful fertilization can occur.
- Led to smaller and more immature egg cells early in development
- Hindered and disrupted growth of the cells
- Caused problems with development of somatic cells and elevated certain cell markers.
The new research shows that zinc plays an important role in oocyte growth at an earlier stage than previously investigated, which is during development and before division. The research also showed why preconception nutrients are needed months before the eggs fully develop to give the best outcomes for a healthy pregnancy.
It is estimated that about 17 percent of the global population may be deficient in zinc, due to poor dietary intake their diet. But the estimate may not include cases of marginal zinc deficiency, where people may be getting zinc in their diet, but not enough for their recommended levels. People that are more susceptible to zinc deficiency are those with dietary and disease factors such as irritable bowel syndrome, Crohn’s disease, gastrointestinal disorders and liver disease, those with eating disorders, those with certain dietary restrictions, such as vegetarians or vegans, who may not then be taking supplemental zinc.
Preconception planning, care and management is so important for a healthy pregnancy to occur and should start months before trying to conceive. This is to ensure that the sperm are in optimal health and quality and also to make sure that the egg quality is optimal and in the best quality it can be as well. This is what I do for all my fertility patients and is a crucial part in the high success of my fertility program that has now helped over 12,500 babies into the world.
Dr Andrew Orr
-No Stone Left Unturned