What is PCOS?
PCOS stands for Polycystic Ovarian Syndrome. PCOS is a reproductive disorder caused by elevated levels of androgens in women. It is currently the most common female endocrine disorder. Insulin resistance, irregular periods, acne, cravings, cysts on the ovaries and difficulty losing weight and increased weight gain are all reported in PCOS.
What is insulin resistance?
Insulin is a hormone which is produced by the pancreas. On of its main functions is to control the amount of glucose in the blood. It helps to move glucose out of the blood and into cells, where it is broken down to produce energy.
However, insulin resistance means that the body's tissues are resistant to the effects of insulin. The body therefore has to produce extra insulin to compensate.
High levels of insulin cause the ovaries to produce too much testosterone which interferes with the development of the follicles and prevents normal ovulation. Irregular ovulation is a key factor which can contribute to difficulty in getting pregnant.
Insulin resistance in women with PCOS is associated with an increased risk of the development of type 2 diabetes.
What can you do to treat insulin resistance?
Weight loss of 5% of body weight in those who are overweight or obese has been shown to lead to improvements in PCOS, specifically in insulin resistance, testosterone production and ovulation.
The glycaemic index is a food ranking system which rates how quickly your blood glucose levels rise after eating different carbohydrates. Low GI sources of carbs include wholegrain breads and cereals, oats, beans, lentils, vegetables and many fruits. A diet which sources most of its carbohydrates from low glycaemic index (GI) sources has also shown to be beneficial in PCOS. Choosing low GI carbohydrates results in your blood glucose levels to rise slowly, which can in turn improve insulin levels.
Another emerging area of research which is being examined is whether omega-3 fatty acids can offer a benefit to those who have PCOS.
What is the current evidence surrounding omega-3 fats and PCOS?
The role of omega-3 long chain polyunsaturated fatty acids, commonly referred to as PUFAs, have been researched for many conditions, including PCOS. Eicosapentaenoic acid (EPA) and docosahexaenoic acid (DHA) are omega-3 long chain PUFA found primarily in fatty fish such as salmon, mackerel and sardines.
A 2011 study by Phelan et al. found that daily supplementation of 2.4g omega-3 long chain PUFAs in a randomized, placebo-controlled, crossover trial reduced plasma testosterone levels in women with PCOS.
What did this study find?
This double-blind, randomized, controlled clinical trial aimed to examine the effects of omega-3 long chain PUFA supplementation in women who were diagnosed with PCOS. Participants were aged between 20–35 years old and had a body mass index (BMI) that ranged from 25–40 kg/m2, or between the overweight and obese BMI categories.
One group of women received the omega-3 supplement daily for eight weeks while the other group, known as the control group, received a placebo supplement which contained no omega-3.
At baseline before the study commenced, there were no significant differences between the 2 groups in terms of serum glucose, insulin, HOMA-IR, However, it was found that the women who received the omega-3 supplement had significant decreases in serum glucose, insulin, and HOMA-IR. Supplementation with omega-3 fatty acids resulted in 11.4%, 8.4%, and 21.8% reduction in serum levels of glucose, insulin, and HOMA-IR, respectively, compared with the placebo group. These results suggest that participants had significant reductions in insulin resistance and improvements in insulin sensitivity.
The effect of omega-3 supplementation on other important parameters in PCOS were also investigated. However, omega-3 fatty acid supplementation had no significant effects on weight, body mass index (BMI), waist circumference or waist to hip ratio at the end of the study.
Should I take a fish oil supplement if I have PCOS?
PCOS is a multifactorial disease, meaning that there won’t be one magic cure. Diet, lifestyle and supplementation can all play a key role in managing PCOS.
As mentioned previously, choosing to source the majority of your carbohydrate intake from low GI sources has been shown to be beneficial. In addition to this, a high protein diet has been shown to be useful in managing blood sugar levels and appetite.
Meal timing has also shown to play a role in PCOS. One study found that eating most calories at breakfast, followed by lunch then dinner, improved fertility, insulin and hormone levels in women with PCOS. This meal pattern is proposed to be better suited to our body’s natural circadian rhythm which can in turn help with insulin resistance and inflammation.
An omega-3 supplement is a good option to try alongside other diet and lifestyle modifications. This is especially true if you don’t include oily fish such as salmon regularly in your diet. If buying a supplement, make sure it’s a high quality fish oil with only pure omega-3 without any omega-6 or omega-9 fatty acids added in as the beneficial effects have been seen with pure omega-3 supplements.
There are also a number of other supplements which have shown promise in PCOS management. Research is promising for the use of inositol in PCOS to reduce insulin resistance alongside improved period regularity, improved regularity of ovulation and reduced testosterone levels. Chromium picolinate has also received attention. Results from a study reported that supplementation of 200µg of chromium picolinate in women with PCOS resulted in reduced blood sugar levels and increased insulin sensitivity.
As always, supplement recommendations should be individualised and not blanket recommendations. This is why we recommend speaking to a fully qualified nutritionist if you have PCOS or are wondering about supplementation.