PCOS and Dairy

Women with polycystic ovary syndrome (PCOS) face many conflicting decisions on what foods to include or exclude in their meals and snacks each day. In this article, we’ll tackle the controversial topic of PCOS and dairy.

We have previously discussed the role of other controversial foods like PCOS and Gluten and PCOS and Soy. 

There are very few studies exploring the effect that dairy may or may not have in women with PCOS. We found only two studies that directly studied the effect of dairy in women with PCOS. The first study found that milk intake may increase the risk of PCOS (1). The second study was an 8-week trial in which women with PCOS were instructed to follow a low-starch and low-dairy diet. Following this diet resulted in significant weight loss, improved insulin sensitivity, and reduced testosterone levels. However, there was no control group and it is difficult to extrapolate whether the results were due to less dairy intake or the low carbohydrate nature of the diet (2).

Despite the lack of research evaluating the role of dairy in women with PCOS, there are a few areas in which dairy may affect women with this condition.

PCOS is the most common cause of ovulation-related infertility. Unfortunately, infertility affects up to 40 percent of women with PCOS. Increased intake of low-fat dairy products may increase the risk of ovulation-related infertility (3). Interestingly, high-fat dairy was found to decrease this risk. However, this does not necessarily mean low-fat dairy harms fertility or high-fat dairy improves fertility (4).

Consuming dairy products may worsen acne, a common symptom that affects up to 30 percent of women with PCOS. While some studies report an increased frequency of acne with only low-fat and fat-free milk products, other studies report that all types of dairy increased acne occurrence (5, 6, 7). Read about our PCOS Acne Diet.

Dairy (or lactose) intolerance is fairly common. In fact, up to 70 percent of the world population may have some form of lactose intolerance, although there is wide variation in this percentage between different regions (8). Lactose intolerance is the inability to digest lactose, the main sugar found in milk products, and can cause gas, bloating, and/or diarrhea. We find that many individuals tend to have a sensitivity to dairy as well. Food sensitivities occur when your immune system overreacts to a particular food which can trigger inflammation, leaky gut, and an imbalance in gut bacteria (dysbiosis). Women with PCOS are more likely to have leaky gut and dysbiosis than women without PCOS (9). Temporarily eliminating food sensitivities as part of a gut healing protocol can reduce inflammation, treat leaky gut, and rebalance your gut bacteria. 

Women with PCOS are three times more likely to also have an autoimmune thyroid disease called Hashimoto’s (10). Lactose intolerance is fairly common in Hashimoto’s, with one small study reporting lactose intolerance in 75 percent of individuals. Interestingly, the same study found that lactose restriction significantly decreased TSH levels (11). This means that decreasing lactose in milk containing products may have improved thyroid function. When TSH is high, this is a signal from the brain that there is not enough thyroid hormone circulating. So, when TSH is lower but still within range, this can mean the thyroid is functioning better. 

The case for a dairy-free diet in women with PCOS is nuanced and individualized. We recognize that eliminating dairy may not be essential for everyone. However, similar to gluten, we find that many of our patients have a dairy sensitivity, lactose intolerance, or simply feel better on a dairy-free diet. The best way to evaluate your body’s reaction to dairy is to temporarily eliminate it from your diet. We often recommend a three week dairy elimination for most of our patients with PCOS, especially if they are also suffering from digestive symptoms or have a thyroid condition, like Hashimoto’s. 

If you choose to keep dairy in your diet, choose organic, pasture-raised, and whole-fat dairy products. Alternatively, if you choose to trial a dairy elimination, keep in mind that some dairy-free products contain high amounts of added sugar or artificial sweeteners that can worsen PCOS symptoms.