Iron and the Female Athlete

Iron and the Female Athlete

One of the basic requirements for the female athlete is meeting her daily caloric needs in order to maintain both good health and good athletic performance. Optimal energy availability is referred to anything above 45 kcal per Kg of fat free mass (FFM) and poor energy availability is referred to anything below 30 kcal per Kg of FFM.

How to calculate FFM?

FFM (Kg) = Body weight (Kg) – Fat mass (Kg)

Active female athletes might need around 2500 kcal per day whereas competitive female athletes training for longer hours weekly might require 3000 kcal per day. Problems are encountered when energy needs are not met, and these can be:

  • Inadequate macronutrient intake such as carbs, proteins, fats which are essential for performance, the immune system and brain health.
  • Inappropriate food timing & choices to maintain fitness level and faster recovery
  • Poor micronutrient intakes to support bones (Calcium and Vit D), blood (Zinc, Iron, Vit B9 and Vit B12) and overall health (B Vitamins).

This is called relative energy deficiency (RED) in sports that can affect males as well as females. RED does not only present disordered eating like low energy availability, but can also cause irregular menstruation (oligomenorrhea) or even no menstruation at all (amenorrhea) and a decreased bone density, also known as osteoporosis or osteopenia.

What to do to prevent RED:

  • Eat enough food (no more and no less than your daily caloric requirements): It will help keep you energetic for training.
  • Consume 2000+ kcal per day if you’re a female athlete of which 1.2-2g per kg of your body weight coming from proteins.

What to avoid to prevent RED:

  • Eating less food: Having low energy available will put you at a higher risk of injury, illness, menstrual dysfunctions, higher fatigue and low performance… everything that you don’t want to happen.
  • Restrict calories or macronutrients: Do not skip any food group as it might lead to severe deficiencies especially in Iron, Zinc, Calcium, Vit D and B Vitamins.


Iron is one of the most essential minerals in a female athlete diet because of increased iron demand (long and intense training), elevated iron loss (menstruation) and blockage of iron absorption. Iron’s function is to help carry oxygen via the oxygen and carbon dioxide carrying-molecule, hemoglobin.

Iron balance can be affected by many factors such as the peptide hormone hepcidin, dietary iron intake and absorption, environmental stressors (e.g. altitude), exercise, menstrual blood loss and genetics.

Female athletes are at a heightened risk of iron deficiency compared with non-athletes.

Daily intake values of iron for adult females in the UK is 14.8 mg iron per day and in the US is set at 18 mg iron a day. Additional iron is recommended for pregnant and lactating females. Female athletes are advised to add 10mg of iron per day from the diet as the iron requirements for endurance female athletes are increased by approximately 70 %.


Treatment of iron deficiency includes:

 - nutritional counselling (inclusion of iron fortified or naturally iron-rich products in the diet)

-oral supplementation (side effects might include abdominal discomfort, constipation and nausea)


-descent from altitude

-intravenous injection (when there is a time-critical need like a championships or mountain expedition).


It is not enough to take iron supplementations. Daily dietary iron is way more efficient than iron pills, studies show.


Dietary sources come in two forms:

Heme form comes from animal sources:

-present within hemoglobin or myoglobin molecules and is released by proteolytic enzymes in the lumen of the stomach and the small intestine

-absorption does not require binding proteins, its uptake can be as efficient as 40 %

-constitutes only about 10 % of all dietary iron

- e.g: red meat and liver, Chicken, duck, pork, turkey, eggs and fish.


Non-heme form accounts for all other types of dietary iron:

-is bound to other food components and is usually present in ferric form

-In order for it to be used by the body it must be reduced to ferrous iron by either brush border membrane enzymes or dietary reducing agents and transported by the divalent metal transporter into the enterocyte

-absorption depends on the levels of inhibitors and enhancers, hence, the availability of this form of iron varies greatly from 2 to 20 %

-50 % of total dietary iron comes from grain products

-e.g: green vegetables (spinach, broccoli), lentils and beans, nuts and seeds, grains (whole wheat, brown rice and fortified breakfast cereals) and dried fruits.

Furthermore, the absorption of iron from the whole diet depends also on the levels of promoters like Vitamin C, certain organic acids, meat, fish and shellfish, and inhibitors like phytates, phenolic compounds, tannins (found in coffee and tea) and calcium (found in milk and dairy) present in the diet.

Finally, are you meeting your daily energy needs?

Are you following a well-balanced diet consuming all macro and micronutrient needs?

Do you know how much energy you spend so you refuel accordingly?

It's very important to be aware of all these points to maintain a good overall health. If you’re confused about any of the questions, refer to an expert, a health professional or a medical doctor.

Keep in mind that your health comes above all other goals you have. Athletic performance and body shape are secondary.


Contact us now to start your journey!