Reproductive function is vital to human survival and well-being. Thus, the incidence of polycystic ovarian syndrome (PCOS) in women, often associated with infertility, has received considerable attention among researchers.

A recent study published in the journal Current Nutrition Reports explores the role of the ketogenic diet in the treatment of PCOS.

Study: Ketogenic Diet as Medical Prescription in Women with Polycystic Ovary Syndrome (PCOS). Image Credit: Nina Firsova / Shutterstock.com

Introduction

PCOS is an endocrine condition that affects the ovaries, often leading to various combinations of elevated androgen levels with/or oligo-ovulation or polycystic ovaries. As a result, about four in ten affected women are infertile.

PCOS is also linked to multiple metabolic disorders, including glucose intolerance, type 2 diabetes mellitus, hyperinsulinism, insulin resistance, hypertension, and fatty liver. In addition, an earlier report suggested a link between PCOS and excessive dietary carbohydrate intake, leading to insulin resistance and hyperandrogenism. Obesity is also more prevalent among women with PCOS.

These factors have led many types of diets to be studied for their effect on PCOS, with this research often focused on how the reduced consumption of refined carbohydrates and saturated or trans fats in the diet may be beneficial.

A variation of the Mediterranean diet known as the ketogenic Mediterranean diet with phytoextracts (KEMEPHY), as well as the low glycemic index (GI) diet and low saturated fat diet, are some of the different interventions that have been tested for their efficacy in PCOS management.

In particular, the very-low-calorie ketogenic diet (VLCKD) has garnered support among weight loss enthusiasts and the scientific community due to its purported effectiveness in reducing body fat and alleviating metabolic dysfunction such as glucose intolerance and dyslipidemias.

In the VLCKD, fats provide 90% of calories, with carbohydrates and proteins providing the remaining 10%. This diet is adopted in three stages, beginning with the active stage, followed by the re-education and maintenance phases. The VLCKD has been shown to support rapid weight loss while maintaining lean mass, thus preserving glucose metabolism throughout the process.

The current study reviews available evidence in favor of the VLCKD in treating PCOS.

What did the study show?

Research shows that body composition and carbohydrate metabolism are involved in PCOS. These alterations are exacerbated by obesity and subsequently lead to dyslipidemia and dysregulated carbohydrate and amino acid metabolism, with a specific signature recognizable as that of PCOS.

As a result, PCOS is often associated with obesity, low-grade inflammation, along with insulin resistance, and the resulting hyperinsulinemia.

The current review establishes that weight loss alone is inadequate to improve reproductive function. Therefore, along with reducing the intake of fatty acids and high GI foods, there should be an increase in the intake of omega-3 polyunsaturated fatty acids (PUFA), vitamin D, and chromium-rich foods.

Important dietary interventions

The Mediterranean diet shows preliminary effectiveness in managing PCOS by reducing inflammation, insulin resistance, and androgen levels.

Other dietary interventions tested in this area include the low GI diet, which might reduce inflammation in PCOS through increased glutathione peroxidase activity, a potent antioxidant molecule. Additionally, the pulse-based diet, which provides high-quality proteins, complex carbohydrates, and increased fiber, has resulted in better ovarian morphology and reduced androgen levels.

The Dietary Approaches to Stop Hypertension (DASH) is high in carbohydrates and low in fats and has been shown to reduce insulin resistance, inflammation, and oxidative stress, as well as improve hormonal profiles.

The ketogenic diet (KD)

KD allows very restricted calories from carbohydrates, with 70% of calories supplied by fat. This leads to high ketone levels, mainly acetoacetate and β-hydroxybutyrate.

Interestingly, PCOS patients who consume a KD exhibit activated adenosine monophosphate-activated protein kinase (AMPK) and silent mating type information regulation 2 homolog 1 (SIRT1), both of which are typically observed with calorie-deprived diets. These molecules are essential for increasing insulin sensitivity and enhancing glucose uptake.

KD causes weight loss and reduces fat mass, both of which reduce insulin secretion after meals, restoring insulin sensitivity and improving glucose tolerance. In PCOS, KD can reduce androgen levels and normalize the ratio of luteinizing hormone (LH) to follicle-stimulating hormone (FSH). However, more studies are needed to determine the impact of the KD over time.

VLCKD

The VLCKD has been proposed for treating refractory epilepsy, fatty liver, and obesity in individuals with other illnesses, as well as morbid obesity prior to bariatric surgery. Earlier studies have shown that VLCKD was more effective in reducing weight, fat mass, waist circumference, and blood cholesterol levels than other measures aimed at weight loss.

This approach improved many metabolic areas, including body weight and composition, normalization of serum glucose levels, reversal of hyperinsulinemia, and correction of cholesterol levels. The insulin resistance characteristic of PCOD also disappeared in VLCKD adherents.

Even in lean women with PCOS, VLCKD helps reverse hyperinsulinism and insulin resistance. The weight loss and reduced fat mass associated with VLCKD could restore vitamin D levels to normal by promoting its release from fatty tissue. However, data from long-term VLCKD interventions for PCOS are not yet available.

What are the implications?

For many years, women with PCOS have been advised to lose 5%-10% of their body mass to restore insulin sensitivity and glucose tolerance, as these factors are essential for restoring metabolic regulation. However, the optimal approaches to achieve this goal have yet been established.

The current study suggests that the VLCKD could potentially help treat PCOS in the long term as a result of its considerable success in achieving weight loss, improving body composition, and reversing insulin resistance. An important caveat is that this diet must be carried out under the guidance and supervision of health professionals.

It is evident that the nutritional approach in treating PCOS is essential, whether in controlling body weight, IR, or treating associated comorbidities through different strategies. It seems essential to continue carrying out studies that generate evidence on which dietary pattern is most indicated for managing this condition.”

Journal reference:

• Barrea, L., Camajani, E., Cernea, S., et al. (2023). Ketogenic Diet as Medical Prescription in Women with Polycystic Ovary Syndrome (PCOS). Current Nutrition Reports. doi:10.1007/s13668-023-00456-1.