Low-Carb Diets and Your Hormones
Let’s be honest – it can be challenging to navigate the world of nutrition. There are many different dietary tools and trends that we see popping up, whether we hear about them from a friend, see it on our social media timeline, or read about it on a website. There are so many options and opinions out there and it can be tough to know what is the right fit for you.
What is the Ketogenic Diet?
I’m sure we’ve all heard of low-carb diets. A low carb diet that gained a lot of popularity in the early 2000s was the Atkins diet, and although not new, the one that we hear more about in recent years is the Ketogenic diet. Low Carb Ketogenic Diets (LCKD) involve a diet that consists of approximately 75% fat, 20% protein, and only 5% carbs. The premise behind this is that it mimics the metabolic state of starvation, at which point rather than using carbohydrates (ie.glucose) for energy, our body produces ketones from fat as an alternate source of energy production. It is well documented that the ketogenic diet can be beneficial for certain conditions, the most prominent one being epilepsy (1). There are also studies looking into its use for metabolic conditions such as diabetes, and its use shorter-term for weight loss. (2) (3) (4).
**What about the paleo diet? Paleo and ketogenic are not one in the same. Despite the fact that people following a paleo style diet do not include grains, there are other sources of carbs in the diet such as root vegetables and fruit.
Carbs and Hormonal Health
Although it can be a great option for many people, going low carb longer term can wreak havoc on female reproductive hormones. I see a lot of individuals of reproductive age at the clinic, and it is not uncommon to see women following a low carb diet to be dealing with issues such as amenorrhea (no period) or other menstrual irregularities that suggest anovulation (no ovulation). In fact, in addition to weight loss, the most common side effects in epileptic patients following a ketogenic diet is menstrual dysfunction (5). Ovulation is a sign that we are getting proper signalling from our brain and that we have good healthy estrogen and progesterone levels. There is not a ton of literature on the topic, but perhaps what is happening is that the state of lower carbohydrates is signalling to the hypothalamus that the body is in starvation mode, therefore it is not safe to produce a new life. This prevents the pituitary from releasing LH to stimulate the ovaries to ovulate.
It is known that production of our thyroid hormones (T3 & T4) decreases during fasting periods, and individuals with epilepsy following a ketogenic diet for longer than a month are at greater risk for thyroid dysfunction (6). If carbohydrates play a role in our thyroid function, and our thyroid function is closely linked to our reproductive hormones, could this also be part of it?
This is an exception for low carb diets and hormones. Studies suggest that overweight or obese women with Polycystic Ovarian Syndrome (PCOS) can have improved fertility by adopting a low carb diet. As PCOS can be considered a metabolic condition linked to insulin sensitivity, this makes sense. Perhaps for these women, they should focus on less than 45% of their total caloric intake being from carbs (healthy carbs like some I have listed below). (7)
Low carb diets can be a good option for a lot of people, but they might not be the best idea for someone with:
- Low thyroid function
- Absent or irregular periods *(unless elevated BMI with PCOS)
- Pregnancy or in women trying to conceive (8)
As with anything, there is no one-size-fits-all approach to nutrition and it is good to balance the pros and cons. Our primary objective should be to nourish our bodies by focusing on whole foods, including an abundance of fresh local produce rather than foods that come from a package. I do agree that if our main source of carbs come from sugar and refined flours, it makes sense to cut this out. For women of reproductive age, try replacing it with paleo-friendly carbs such as sweet potatoes, parsnips, carrots, beets, squash, and fruit. If not following a paleo approach, you can incorporate grains such as brown rice and quinoa.
If you are looking to address a specific health complaint or goal utilizing nutrition, it is best to consult with a health professional to make sure you are doing it in a safe and effective manner!
- Liu et al. Ketogenic diet for treatment of intractable epilepsy in adults: A meta-analysis of observational studies. Epilepsia Open. 2018 Feb 19;3(1):9-17.
- Goday et al. Short-term safety, tolerability and efficacy of a very low-calorie-ketogenic diet interventional weight loss program versus hypocaloric diet in patients with type 2 diabetes mellitus. Nutr Diabetes. 2016 Sep 19;6(9).
- Hussain et al. Nutrition. Effect of low-calorie versus low-carbohydrate ketogenic diet in type 2 diabetes. 2012 Oct;28(10):1016-21.
- Volek and Sharman. Cardiovascular and hormonal aspects of very-low-carbohydrate ketogenic diets. Obes Res. 2004 Nov;12.
- Mady et al. The ketogenic diet: adolescents can do it, too. Epilepsia. 2003 Jun;44(6):847-51.
- Kose et al. Changes of thyroid hormonal status in patients receiving ketogenic diet due to intractable epilepsy. J Pediatr Endocrinol Metab. 2017 Apr 1;30(4):411-416.
- McGrice and Porter. The Effect of Low Carbohydrate Diets on Fertility Hormones and Outcomes in Overweight and Obese Women: A Systematic Review. Nutrients. 2017 Feb 27;9(3)
- Sussman et al. A gestational ketogenic diet alters maternal metabolic status as well as offspring physiological growth and brain structure in the neonatal mouse. BMC Pregnancy Childbirth. 2013 Oct 29;13:198.