Vegetarian diets, Triathletes, and Iron

This is the second of an undetermined amount of articles that will help triathletes (or athletes in general) make an educated change to either reduce meat consumption or become vegetarian.  This article will focus on acquiring enough iron in the diet, which is a big concern of people, especially athletes.  First let’s being with why iron is important in the diet and why the body needs iron to function properly and perform at the levels endurance athletes demand from it.

Iron’s main role in the body is for blood cell function.  It plays a fundmanetal role in the hemoglobin molecule. Hemoglobin is the molecule that carries oxygen to the tissues from the lungs and returns with carbon dioxide from the cells.  Although iron is both plentiful and obtainable from a wide variety of foods, iron deficiency is still the most common form of mineral deficiency. The most susceptible groups to iron defiency are children and adolescents, pregnant women, women of child-bearing age, athletes (due to a phenomenon called “heel strike anemia”), and older adults.

Iron also plays other roles in the body, such as:

  • Supporting the action of many enzymes (especially for energy production)
  • Antioxidant
  • May have anti-cancer properties
  • Powerful immune-system booster

Just like fat, carbohydrates, and protein, not all iron is created equally.  There are two forms of dietary iron are available: Heme iron and non-heme iron. Heme iron is effectively animal hemoglobin and is found abundantly in meat and animal products, especially kidney and liver, and is very well absorbed by the body. Non-heme iron is the mineral form of iron and is found in plants. Non-heme iron is poorly absorbed, which makes acquiring adequate amounts of iron in a vegetarian diet difficult.  Even though someone might be eating enough non-heme iron according to the nutrition labels on food, they may not be absorbing enough as it passes through their body.

Heme-iron is absorbed at a rate of about 25-35%, and non-heme iron is absorbed at only about 3%! There are tricks to increase iron absorption.  While eating sources high in iron, eat something that has a high Vitamin C level.  Vitamin C breaks down the iron before it gets to the gut and increases absorption.  Good sources of vitamin C include citrus fruits and juices, tomatoes, strawberries, melons, dark green leafy vegetables and potatoes.  Also, avoid eating foods high in calcium (dairy, etc.) because the calcium binds with the iron making it next to impossible for the iron to be absorbed.  Other factors may decrease the availability of iron. Coffee and tea consumption at the time of a meal can significantly decrease iron absorption.

Many foods in a vegetarian diet contain a high amount of iron, and should be eaten regularly to get enough iron.  If you feel the need to, take a multi-vitamin with iron in it to boost the amount of iron in your diet.  The daily recommended intake of iron per day is about 17.8 milligrams.  Below is a table of vegetarian foods that are high in iron labeled in milligrams:


Breads and cereals
wheat bread, enriched 1 slice 0.6
wheat bread 1 slice 0.5
whole grain cereals 1/2 cup 4.5-9.5
iron fortified cereals 1 cup 1.1-4.5
iron fortified cereals (100% DRI) 1 cup 17.8
Macaroni, noodles, enriched 1/2 cup 0.7
Fruits and vegetables
dried beans, cooked 1/2 cup 2.6
dried peas, cooked 1/2 cup 1.7
lentils, cooked 1/2 cup 2.1
greens, cooked 1/2 cup 1.8
dried apricots 10 halves 1.9
dates 5 1.2
raisins 1/4 cup 1.4
prunes 5 medium 1.2


Food Serving Size Iron % Guideline
soybeans 250ml 9.3 mg 52%
raw yellow beans 100g 7 mg 39%
lentils 250ml 7 mg 39%
falafel 140g 4.8 mg 27%
soybean kernels 250ml 4.7 mg 26%
toasted sesame seeds 30g 4.4 mg 25%
spirulina 15g 4.3 mg 24%
candied ginger root 30g 3.4 mg 19%
spinach 85g 3 mg 17%


Other foods high in iron are quinoa (2.8 mg/1 cup cooked), egg (0.9 mg), and green beans (1.1 mg/1 cup).

 So, if you make the switch to vegetarian or a reduced meat diet, how will you know when the iron levels are low?  Before that question is answered, here is a list of symptoms of being iron deficient:

  • Extreme fatigue
  • Pale skin
  • Weakness
  • Shortness of breath
  • Headache
  • Dizziness or lightheadedness
  • Cold hands and feet
  • Irritability
  • Inflammation or soreness of your tongue
  • Brittle nails
  • Fast heartbeat
  • Unusual cravings for non-nutritive substances, such as ice, dirt or starch
  • Poor appetite, especially in infants and children with iron deficiency anemia
  • An uncomfortable tingling or crawling feeling in your legs (restless legs syndrome)

Because of the lifespan red blood cells (about 90 days), iron defiency anemia won’t show up for a few months.  The most notable change will be a consistent lack of energy despite how much sleep.  Your friends and family may notice you being more irritable.  To be on the safe side, go to your doctor before the switch to see how your iron levels are, and get the level checked periodically throughout the year.

If you find yourself in a state of iron deficency, you may need to consider taking a iron supplement.  Eating meat that is high in iron (red meat, liver, etc.) once or twice a week may be needed too.


For information on getting enough protein for endurance athletes, click here.

For information Vitamin B12 and its role in athletes, click here.