Sam Tryon, MS, RD

Sam Tryon, MS, RD


For some, the idea of not having their period might be cause for celebration.  No cramps, bloating or having to worry about keeping tampons or pads on hand; awesome right?! Unfortunately, not getting your period could be cause for concern.*

If you are 16 years old and have not yet started your period or if you have missed at least 3, you could be diagnosed with amenorrhea.1 Amenorrhea can be caused by a variety of factors including genetic abnormalities, gland problems, and certain gynecological conditions.1  Amenorrhea may also be due to what you eat and how active you are.

The roles of nutrition and activity

Low energy availability is one cause of amenorrhea.  Energy availability is a measure of the energy left for bodily functions (i.e. heart beating, digestion, breathing) after subtracting for energy used during exercise and other activities of daily living (i.e. vacuuming, walking to work, gardening).  Low energy availability means that there is not enough energy for body functions and exercise.

Low energy availability can be a result of not taking in enough fuel (A.K.A. not eating enough) and/or using too much energy for exercise.  Among other effects, the lack of energy left for bodily functions leads to decreased production of gonadotropin-releasing hormone, a hormone important in reproduction, which causes decreased production of estrogen and progesterone and disruption of the menstrual cycle.2

Amenorrhea and Bone Health

Both low energy availability and reproductive hormone changes have negative impacts on bone density.  In addition to not having the available energy and nutrients to maintain bone mass, lack of estrogen is associated with bone loss.  In a healthy body, our bones are constantly being broken down to release minerals like calcium and then rebuilt.  Without estrogen, there is increased breakdown without rebuilding which leads to decreased bone density.  This can progress to osteopenia and osteoporosis, putting a person at risk for fractures.  

Studies have found that up to 95% of people with Anorexia Nervosa have osteopenia and as many as 40% have the more severe osteoporosis.3 Weight gain is associated with return of menstruation and possible reversal of at least some bone loss.

Amenorrhea and bone loss are especially concerning in adolescents as peak bone mass is reached during this time. Bone loss from low energy availability during this stage of life may prevent patients from reaching a normal peak bone mass. This can put them at increased risk for fractures later in life.

Next Steps

If you have missed 3 or more periods, an appointment with your general physician can help to determine the cause of amenorrhea.  They may recommend a bone density test to look for possible bone loss.  

If the cause is found to be nutrition related, a dietitian can help you change your diet to make sure you are taking in enough energy to fuel your body. Amenorrhea can occur with or without disordered eating and a dietitian can also help assess for any disordered eating behaviors.  If disordered eating is a problem, a therapist may be added to the team to best tackle these concerns and get you back to the activities you love.  

*The content of this article is for informational purposes only and does not constitute medical advice, professional diagnosis, or treatment.  See your healthcare provider before making any healthcare decisions or with any questions you have regarding a medical condition.  


  1. Amenorrhea. Eunice Kennedy Shriver National Institute for Child Health and Human Development; [accessed 2017 May 31].

  2. Mallinson, R and De Souza, M. Current perspectives on the etiology and manifestation of the “silent” component of the Female Athlete Triad. Int J Womens Health. 2014; 6: 451–467

  3. Mehler, P and MacKenzie, T. Treatment of Osteopenia and Osteoporosis in Anorexia Nervosa: A Systematic Review of the Literature. Int J Eat Disord. 2009; 42: 195-201