Iron and adolescents

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The human body continuously requires iron in trace amounts to carry out numerous functions throughout one’s lifetime. That’s especially true for the adolescent years. Iron is important for the development of all of the body’s tissues, including the brain1.

The symptoms of low iron levels in adolescents

Iron deficiency in adolescence has been associated with fatigue, headaches, restless leg syndrome, irritability, exercise intolerance and impaired learning disability2,3. If the iron deficiency is significant, this could lead to iron deficiency anemia which is associated with symptoms of fatigue, reduced exercise capacity, cardiac palpitations, dizziness, malaise, pallor and breathlessness4,5.

Blood cell changes in adolescence

There is an essential relationship between iron, red blood cells and oxygen. A substance called hemoglobin resides in your red blood cells. Hemoglobin helps carry oxygen to your entire body. Iron is required to make the hemoglobin in your red blood cells.  Without enough iron, your body cannot make enough hemoglobin, and this can cause iron-deficiency anemia.

Changes occur to red blood cells during adolescence which impact the need for iron. Hemoglobin levels change with age and reach their adult level at around 15 years of age5. During puberty, the total amount of hemoglobin is greater in boys than in girls6. The hemoglobin values decrease in girls between the ages of 14 and 20, whereas they increase for boys of the same age group6.

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The risk factors of low iron levels in adolescents

There are risk factors that may increase one’s chances of being iron deficient. You can read about them in detail here. The following factors may also increase an adolescent’s risk of low iron levels;

Growth spurt in adolescence3

Girls generally go through a growth spurt 6 to 12 month before their first period and then their growth significantly slows down. Boys, on the other hand, tend to have a growth spurt two years later than girls, and the growth spurt for boys can last longer7.

Reduced levels of iron may occur during periods of growth acceleration when the mass of red blood cells is growing. A reduction in the blood’s ability to carry oxygen can lead to fatigue, weakness and reduced work capacity1.

Low intake of iron in foods3

Iron deficiency is often caused by insufficient consumption of iron available in foods. This can be due to an inadequate nutrition intake6 or a vegetarian or vegan diet.

Vegetarian diet3

The iron found in plant-based foods is not a well absorbed as the iron from animal foods5. People who follow a vegetarian diet need about 1.8 times more iron than non-vegetarians5. There are over 7 million Canadians between the ages of 18-19 who follow a vegetarian diet. The second largest group consists of 6 million vegetarians between 20 and 29 years of age. All other age-groups have a reduced number of vegetarians compared to the younger demographic8

Refer to the Iron Rich Food Guide for more information on plant sources of iron.


For teenage girls, their main causes of iron deficiency are inadequate iron intake as part of their diet and increased loss of iron due to menstrual bleeding2. It has been shown that approximately 10% of women in the United States are affected by heavy menstrual bleeding2.

Pregnant women5

Adolescent girls who become pregnant have an increased physical demand for iron3,5.

Regular intense exercise

People who exercise regularly at an intense rate increases their need for iron by 30% to 70% compared to people who do not exercise at this same level5.

Excessive intake of cow’s milk

Some children have an excessively high intake of cow’s milk. This can result in the child not feeling the need to consume iron-rich foods5.

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Evidence of benefits of iron supplementation in teenagers

The good news is that iron supplementation in teen girls has been shown to improve concentration, verbal learning and memory compared to teen girls who did not take iron supplements2.

Recommended dietary intake of iron for adolescents

Iron supplementation may help maintain strong iron health. The table below summarizes the dietary recommendations and tolerable upper levels iron for adolescents;

Recommended Dietary Allowances (mg/day) Tolerable Upper Intake Levels (mg/day)
Ages Males Females Pregnant




Males Females Pregnant/



14-18 years 11 15 27 10 45 45 45

Adapted from Nutrition Guideline; Iron, Alberta Health Services, 2018.5

During growth spurts, teenage boys and girls need an additional 2.9 mg/day and 1.1 mg/day above the recommended dietary allowances respectively. Also, the recommendation for adolescent girls assumes that they have begun their menstruation by the age of 14. If it has not begun, they should take a reduced amount of 10.5 mg/day5.

If you have concerns about your iron health or your teen’s iron health, try our iron deficiency symptoms checker. Take the results to your physician or pharmacist and ask about the benefits of iron supplementation.

Biosyent offer a wide range of Feramax® iron supplements. Talk with your healthcare professional or professional drug pharmacist to see which is right for you.



  1. Samson, K. L. I., Fischer, J. A. J., & Roche, M. L. (2022). Iron Status, Anemia, and Iron Interventions and Their Associations with Cognitive and Academic Performance in Adolescents: A Systematic Review. Nutrients, 14(1), 224. https://doi.org/10.3390/nu14010224
  2. Wang, W., Bourgeois, T., Klima, J., Berlan, E. D., Fischer, A. N., & O’Brien, S. H. (2013). Iron deficiency and fatigue in adolescent females with heavy menstrual bleeding. Haemophilia : The Official Journal of the World Federation of Hemophilia, 19(2), 225–230. https://doi.org/10.1111/hae.12046
  3. Government of British Columbia. (2019). Iron Deficiency – Diagnosis and Management – Province of British Columbia. Gov.bc.ca. https://www2.gov.bc.ca/gov/content/health/practitioner-professional-resources/bc-guidelines/iron-deficiency
  4. Donker, A. E., van der Staaij, H., & Swinkels, D. W. (2021). The critical roles of iron during the journey from fetus to adolescent: Developmental aspects of iron homeostasis. Blood Reviews, 50, 100866. https://doi.org/10.1016/j.blre.2021.100866
  5. Alberta Health Sciences. (2018). Nutrition Guideline Iron. https://www.albertahealthservices.ca/assets/info/nutrition/if-nfs-ng-iron.pdf
  6. PLUNCEVIC GLIGOROSKA, J., GONTAREV, S., DEJANOVA, B., TODOROVSKA, L., SHUKOVA STOJMANOVA, D., & MANCHEVSKA, S. (2019). Red Blood Cell Variables in Children and Adolescents regarding the Age and Sex. Iranian Journal of Public Health. https://doi.org/10.18502/ijph.v48i4.1004
  7. John Hopkins Hospital. (2020, November 16). What is a Growth Spurt During Puberty?org; Johns Hopkins All Children’s Hospital. https://www.hopkinsallchildrens.org/ACH-News/General-News/What-is-a-Growth-Spurt-During-Puberty
  8. Vegetarian and vegan population Canada, by age 2022. (n.d.). Statista. Retrieved March 13, 2023, from https://www.statista.com/forecasts/954924/number-of-vegetarians-and-vegans-canada.


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