Low-Fat Dairy and Infertility: What Is the Connection?

Female infertility is a common and difficult condition to deal with — both mentally and physically. About 15% of all women are unable to conceive within the first year of trying. They experience these challenges for many different reasons. And it’s not always clear why it’s harder for some more than others.

In 2007, a large research study focused on dietary connections to infertility. Researchers found that women who ate and drank more low-fat dairy products had an increase in infertility rate. This study led many people to believe that low-fat dairy was harmful when trying to get pregnant. But, like most research, there’s more to this study than meets the eye. 

What is the connection between low-fat dairy and fertility?

The controversy over low-fat dairy and fertility started with a large study that followed more than 18,000 women over the course of 8 years. Results showed that the women who consumed more low-fat dairy products (over two servings per day) had higher rates of infertility compared with those who consumed very little dairy (less than one serving per week). 

The researchers also found that women who consumed high-fat dairy had a slightly lower risk of infertility compared with those who ate very little dairy. But this result was less significant. 

Before this changes the way you think about your own fertility, it helps to understand a few important details of the study: 

• This was not a randomized control trial. A randomized control trial would have provided much higher quality data to answer the question at hand.

• Diet was assessed through a self-reported questionnaire. And each participant filled out this questionnaire only twice over an 8-year period. 

• The low-fat dairy products in the study included a wide variety of dairy products, such as milk, yogurt, ice cream, soft cheeses, and hard cheeses. 

• The study population excluded many different groups of people, like women with diabetes. It was also a group of women who were not necessarily trying to become pregnant. This isn’t the best representation of women who have difficulties with infertility.

• The researchers found an association between low-fat dairy and infertility. That doesn’t mean low-fat dairy products cause infertility. There are many other factors at play.

• Researchers looked specifically at anovulatory infertility, which is just one cause of infertility. (We explain that more in the next section.) 

While this study was helpful in starting the conversation about low-fat dairy and infertility, other studies show different results.

A 2016 study looked at more than 200 women going through in vitro fertilization (IVF). The study accounted for factors like age, nutrition, smoking, body mass index (BMI), race, and a pre-existing infertility diagnosis. Higher overall dairy intake (including cheese, low-fat dairy products, and yogurt) was positively associated with more live birth outcomes. This study also found no difference between the women who consumed low-fat or full-fat dairy products.

Even meta-analyses — large reviews of the research — find controversy in dairy consumption. There are many factors that play a role in infertility. Since research is mixed, much more is needed to fully understand the relationship between dairy and fertility. 

What is anovulatory infertility?

As mentioned above, the first study on low-fat dairy and infertility looked specifically at anovulatory infertility. Anovulatory infertility is caused by the absence of normal ovulation. 

In a typical menstrual cycle, ovulation occurs when the ovary releases an egg. This egg then travels to the uterus, where it can become fertilized with male sperm to become pregnant. So anovulatory infertility happens when the ovary doesn’t release an egg. 

Anovulatory infertility has many different causes. Some examples include:

• PCOS (polycystic ovarian syndrome)

• Hormone imbalances

• Pituitary diseases

• Thyroid conditions

Anovulatory infertility is just one cause of infertility. There are also many causes of infertility that aren’t directly tied to ovulation. Age, injury, changes to the ovaries or uterus, and even lifestyle may contribute to female infertility. In some cases, infertility may also be due to male sperm issues.

Does full-fat dairy also affect fertility?

Research results vary when it comes to dairy’s role in fertility.

One study with more than 17,000 women showed a 66% lower risk of infertility with a diet that included:

• Full-fat dairy

• Monounsaturated fats

• Plant proteins 

This study also found that women who ate or drank full-fat dairy were more likely to get pregnant. 

But, the positive results were not because of full-fat dairy alone. They were based on overall habits and nutrition. The women who became pregnant also had: 

• More vegetables and healthy fat sources

• Lower glycemic foods that were less likely to cause a rise in blood sugar

• Multivitamins

In this study, there were many other dietary changes associated with successful pregnancy. This makes it difficult to find a direct link between full-fat dairy and fertility. 

Should you avoid dairy if trying to get pregnant?

If you’re trying to get pregnant, you don’t need to avoid dairy. There isn’t enough research to know if dairy is helpful or harmful for fertility.

“It's never a good idea to cut out entire food groups, such as dairy,” said Caroline L. Young, MS, RD, RYT, owner of Whole Self Nutrition. “This is especially not a good idea when trying to get pregnant. Your body needs a variety of foods and nutrients to be a healthy home for your future baby.”

Because of this, it’s best to focus on building a well-rounded diet. Things like adequate hydration, carbohydrates, proteins, and fats are all important. 

Judy Simon, MS, RDN, CD, CHES, FAND, at Mind Body Nutrition, emphasizes a diet that includes minimally processed:

• Vegetables 

• Fruits

• Whole grains

• Nuts and seeds

• Healthy oils

• Protein primarily from legumes, fish, nuts, and eggs 

“Diet fuels the building blocks of our reproductive system,” Simon said.

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Written by:

Emily Hulse, MS, RD

Emily Hulse, MS, RD, is a registered dietitian and wellness writer. Her writing has appeared in Forbes, Sports Illustrated, and MDLinx, among other online health publications.

Edited by:

Katie E. Golden, MD

Katie E. Golden, MD, is a board-certified emergency medicine physician and a medical editor at GoodRx.

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