Body fat has an important function for fertility. Body fat cells, called adipocytes, produce estrogen. Estrogens are primary female reproductive messengers. Estrogen is essential for healthy bone formation, healthy gene expression, maintaining healthy cholesterol levels, and is vital for a healthy menstrual cycle. Women who do not have adequate amounts of body fat may have menstrual cycle irregularities, anovulation, and infertility problems. Obese women may have too much estrogen due to too much body fat, which may also contribute to fertility problems.
We have all heard of women athletes, who have extreme diet and exercise regimen, to not have a monthly menstrual cycle. While it is important to be healthy and fit, through proper dietary and exercise habits, it is also extremely important to have adequate amounts of body fat. Body fat is necessary for a regular menstrual cycle. Low body fat may also cause ovulation to stop. Some women will continue to have monthly menstruation, but be unaware that she is not ovulating regularly.
MRI Study Shows Low Body Fat Disrupts Ovulation
Many of the studies I have read are either for or against the hypothesis that low body fat may cause anovulation. One study really stood out to me though. A study published in the Journal of Clinical Endocrinology & Metabolism in 1993 used magnetic resonance imaging (MRI) scans of both external and internal body fat deposits of extremely athletic women, compared to nonathletic women. The MRI was used to measure fat deposits in 17 different sites in the body, including that of the thoracic vertebrae compared to fat of the upper thigh. Urinary analysis of estrogen was also tracked.
Results showed that the fat deposits of the extremely athletic women, who had menstrual cycle and ovulatory irregularities, had significantly lower levels of both subcutaneous and internal body fat at all sites in the body compared to the controls. Extreme athletes that had regular ovulation had lower levels of internal body fat at vertebrae lumbar 4, sacral 1, and sacral 4, but had adequate levels of subcutaneous fat. Levels of estradiol (This estrogen is the most potent and abundant. Its main action is the involvement in development of secondary sex characteristics, and the menstrual cycle) was significantly related to total fat at all sites in the body, with the extreme athletes having significantly lower estradiol than those of the controls.
Results of this study shows that extremely athletic women do in fact have lower levels of body fat overall, which may directly decrease fertility. While body mass index (BMI) may be a useful tool for determining general body fat ratio for height and weight, it is not a very useful tool for women who are extremely athletic. This is because BMI cannot determine the actual amount of subcutaneous or internal body fat.
Low Fat Diets and Trans Fats Not Good for Fertility
So, as we have learned, having too little body fat can disrupt the menstrual cycle. Did you know that also consuming too little whole fat foods can also cause problems for our fertility as well? While much of the focus regarding fat in our society has been targeted at the obesity rate, it is important to know the role of good fats in your diet as well. Low fat foods are not good for fertility, nor are trans fats. Fat is essential in the manufacturing of hormones. If you are eating a low-fat diet, there could be issues with ovulation due to lack of progesterone.
A study from the well-known Nurses Health Study at the Harvard School of Public Health was published in the European Journal Human Reproduction. Researchers found that women who ate two or more low-fat dairy products a day were nearly twice as likely to have trouble conceiving because of lack of ovulation than women who ate less than one serving of low fat dairy foods a week.
They found that women eating whole fat ice cream two or more times a week had a 38% increase of fertility than women consuming ice cream less than once a week. That study showed that women who were eating low-fat diets had higher chances of not ovulating, while the women eating real ice cream are having fertility success.
The best whole fat foods to eat would be whole fat organic dairy products, preferably raw.
On the flip side, eating foods high in trans fats may pose risks to fertility as well. Eating trans fats have an effect on the body by interfering with a cell receptor involved in inflammation, glucose metabolism, and insulin sensitivity. Insulin sensitivity and poor glucose metabolism are the same factors that affect the fertility of women who have PCOS.
With every 4 grams of trans fats eaten instead of omega-6 fatty acids, the risks of fertility issues doubles. It is not hard to get 4 grams of trans fatty acids a day, especially if you eat fast foods and processed foods.
Wondering how to get in enough good essential fatty acids daily? You should read our article Omega 3-6-9, Essential Supplement for Fertility and Pregnancy. This article is packed with a ton of information on the best fats to eat daily and why they are important for your fertility.
Regardless of your weight, it is extremely important to be eating good fats daily, avoiding low fat and trans-fat foods, and exercising within healthy limits daily. If you are extremely athletic and have been struggling with fertility, it may be time to change your exercise routine and be sure you have adequate amounts of body fat to ovulate regularly. If you are overweight and obese, it is also important to lower body fat, so that you have balanced hormonal levels. It really all comes down to balance once again. Fat is a mysterious part of our bodies, but it is more important to our fertility than it gets credit for!
- Frisch, R. E. (1993). Magnetic resonance imaging of overall and regional body fat, estrogen metabolism, and ovulation of athletes compared to controls. Journal of Clinical Endocrinology & Metabolism, 77(2), 471-477. doi:10.1210/jc.77.2.471 Retrieved from: https://www.researchgate.net/publication/14854355_Magnetic_resonance_imaging_of_overall_and_regional_body_fat_estrogen_metabolism_and_ovulation_of_athletes_compared_to_controls
- Rodriguez, H. (n.d.). Trans Fats May Increase Infertility Issues. Retrieved from: http://natural-fertility-info.com/eating-trans-fats-may-increase-fertility-issues.html
- Rodriguez, H. (n.d.). Ice Cream Good for Fertility. Retrieved from: http://natural-fertility-info.com/ice-cream-good-for-fertility.html