Part 3: of Insulin Resistance and Fertility
Originally published by Dr. Fiona McCulloch in Naturopathic Currents in September 2013, you can read the original article here.
This article has been broken down into a four part series, links to the other parts of this series are listed below:
Part 3: Diet and Exercise Interventions for Insulin Resistant Fertility Concerns
Diet and Exercise Interventions for Insulin Resistant Fertility Concerns It has been found that each 1kg increase in body weight is associated with a 2.84 day increase in time to pregnancy. Therefore, losing additional weight may significantly reduce the time to successful conception.
A carbohydrate-restricted diet can improve insulin resistance. In one study, insulin response to an oral glucose load was reduced significantly for patients following a low carbohydrate diet.(1) When compared to a low fat diet, a very low carbohydrate diet significantly improved both insulin sensitivity and weight loss in overweight or obese women.
A Duke University study on a very low carbohydrate ketogenic diet caused improvements in American women with PCOS.(2) Over a 24-week period, patients showed significant improvement in free testosterone, LH/FSH ratios, weight loss and fasting insulin.
Interestingly, the Paleolithic diet is showing great promise in treating insulin resistance. The “Paleo” diet includes vegetables, lean meats, fish, fruits, nuts and seeds, and excludes grains, dairy, salt, sugar, and legumes. A 2009 study on a group of type 2 diabetics found that the Paleolithic diet improved glycemic control and reduced HBA1C, triglycerides, insulin and glucose when compared to a traditional diabetes diet.(3)
Exercise is thought to improve fertility for women with PCOS mostly through waist circumference reduction and weight loss (even if modest), which can greatly improve insulin sensitivity. A study on 40 obese women with anovulatory PCOS found that structured exercise improved menstrual regularity, insulin sensitivity, fertility, and androgen levels.(4) The structured exercise program, consisting of three 30-minute stationary bicycle sessions per week, reduced waist circumference (WC) significantly even when only smaller amounts of total body weight were lost. Reduced WC is a result of losing intra-abdominal fat (as opposed to subcutaneous fat, which is often present on other areas such as the hips and thighs). Abdominal fat is a strong sign of insulin resistance and excess androgens.
Women with PCOS are also known to have poor micro vascular uterine function, which may cause implantation failure. Exercise training may improve micro vascular function in PCOS women by enhancing nitric oxide vasodilation.(5)
- Foster GD, Wyatt HR, Hill JO, McGuckin BG, Brill C, Mohammed BS, Szapary PO, Rader DJ, Edman JS, Klein S. A randomized trial of a low-carbohydrate diet for obesity. N Engl J Med. 2003 May 22;348(21):2082-90.
- Mavropoulos JC, Yancy WS, Hepburn J, Westman EC. The effects of a low-carbohydrate, ketogenic diet on the polycystic ovary syndrome: a pilot study. NutrMetab (Lond). 2005 Dec 16;2:35.
- Klonoff DC. The beneficial effects of a Paleolithic diet on type 2 diabetes and other risk factors for cardiovascular disease. J Diabetes Sci Technol. 2009 Nov 1;3(6):1229-32
- Palomba S, Giallauria F, Falbo A, Russo T, Oppedisano R, Tolino A, Colao A, Vigorito C, Zullo F, Orio F. Structured exercise training programme versus hypocalorichyperproteic diet in obese polycystic ovary syndrome patients with anovulatory infertility: a 24-week pilot study. Hum Reprod. 2008 Mar;23(3):642-50.
- Sprung VS, Cuthbertson DJ, Pugh CJ, Daousi C, Atkinson G, Aziz N, Kemp GJ, Green DJ, Cable T, Jones H. Nitric Oxide-mediated cutaneous micro vascular function is impaired in PCOS but can be improved by exercise training. J Physiol. 2013 Jan 14.