Polycystic Ovarian Syndrome (PCOS) is one of the most common endocrine disorders for reproductive aged women in the US with a prevalence of 4-12%; in the EU, the prevalence ranges from 6-8%. This syndrome is characterized by irregular menses, hyperandrogenism, and polycystic ovaries. On clinical examination, PCOS is usually noted by complaints of oligomenorrhea or amenorrhea, hirsutism, and frequently infertility. Risk factors include diabetes (type 1 and type 2) as well as gestational diabetes. In over 60% of patients with PCOS, insulin resistance is a hallmark lab finding that is associated with a number of comorbid conditions including metabolic syndrome (MetS), hypertension (HTN), dyslipidemia, glucose intolerance, and frank diabetes.
Taking into account the strong dysglycemic aspect of this condition, researchers evaluated whether the effects a reduced calorie diet might have on selected metabolic and hormonal profiles in women diagnosed with PCOS.
A total of 60 obese and overweight women, aged 18-40 years with BMI > 25kg/m2 and diagnosed with PCOS, were randomized to either the Dietary Approaches to Stop Hypertension (DASH) diet or to a control diet for 12 weeks. Patients were asked not to change or alter their regular physical activity or to take any additional supplements during the course of the study. All participants provided 3-days dietary recalls and three physical activity records to verify that they maintained their usual diet and physical activity during the intervention. Both dietary recalls and physical activity records were taken at baseline, weeks 3, 6, 9 and 12 during the intervention. Clinical assessments included BMI, insulin and two measurements often taken in cases of PCOS: nitric oxide and serum anti-Mullerian hormone (AMH). Serum AMH is considered a biomarker for PCOS and is often elevated two to three times greater in this population versus normal type women. Decreased levels of nitric oxide bioavailability has been linked to increased risk for cardiovascular disease and past research has shown that nitric oxide levels in patients with PCOS is significantly lower as compared to normal type women.
As all the study patients were considered obese or overweight, both the DASH diet and the control diet were designed to be calorie restricted. Both the DASH dietary plan and the control diet consisted of 52%-55% carbohydrates, 16%-18% proteins and 30% total fats, however, the DASH diet was rich in fruits, vegetables, whole grains and low-fat dairy products and low in saturated fats, cholesterol and sugar.
The results showed:
- Weight and BMI reductions were greater in the DASH group than the control group:
Weight (−4.3±1.4 vs −3.2±1.9 kg, P=.01) and BMI (−1.6±0.5 vs −1.2±0.7 kg/m2, P=.02)
- Significant decreases in serum AMH levels in the DASH group compared to the control group:
Serum AMH (−1.1±3.1 ng/mL vs +0.3±0.7 ng/mL, P=.01)
- Significant decrease in serum insulin levels in the DASH group as compared to the control group: serum insulin (−25.2±51.0 vs −1.2±28.8 pmol/L, P=.02)
- Significant increases in nitric oxide in the DASH group as compared to the control group:
Nitric oxide (NO; +9.0±4.9 vs +0.6±2.3 μmol/L, P<.001)
Why is this Clinically Relevant?
- Clinicians should assess for PCOS in patients who have hallmarks for this condition including central obesity, HTN, infertility, irregular menses and associated patient complaints
- If PCOS is determined by lab values, then clinicians can instruct patients on how to improve outcomes by reducing weight and BMI through implementation of a low calorie diet – preferably the DASH diet (rich in fruits, vegetables, whole grains and low-fat dairy products and low in saturated fats, cholesterol and sugar)
- Increases in exercise and physical activity should also be encouraged
- Monitoring of progress by the regular clinic visits