Home » Health and Nutrition » Iron: Vegetarian Nutrients of Concern #4

Iron: Vegetarian Nutrients of Concern #4

Jennifer Hanes MS, RDN, LD

Many people think iron deficiency is specific to women and problematic during pregnancy.

However, iron absorption and needs are a fickle thing, changing under various circumstances and demands. Iron deficiency, when mild, is typically noted on annual blood work, but if severe, symptoms will lead a person to seek medical attention.

Meat is the most commonly cited source of dietary iron, and iron from meat (called heme-iron) is typically better absorbed. 

However, it is possible to get all of your iron from a vegetarian diet if you know what you’re looking for. 


Iron is a component of hemoglobin, a protein in your red blood cells, which is responsible for carrying oxygen throughout your body.

It is also a component of myoglobin, another protein that is responsible for oxygen transport as well as muscle metabolism and healthy connective tissues.

Other roles include growth, neurological development, and the formation of some hormones.

iron containing cashews in a bowl on a black table
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Recommended Intake

Men aged 19-50 should aim for 8 mg per day. Women in that age group should take in at least 18mg! Blood loss is the primary cause of iron loss, making menstruating women require higher intake.

Pregnancy increases iron needs to 27mg per day, mainly due to a large increase of red blood cells and the growth of the fetus. 

After the age of 51, the RDA for men and women is 8mg.

Sources of Iron

As mentioned above, this mineral comes in 2 forms, heme and nonheme.

Heme iron is found in meat and is more readily absorbed by the body, though there may be some health concerns related to excessive intake of heme-iron, particularly from red meat.

Nonheme iron is found in plants and fortified foods. The best sources of these are fortified breakfast cereals, beans and lentils, and cashews.

Vitamin C increases your absorption of iron, so top a salad with beans and use a citrus vinaigrette dressing. Or have cashews and a cutie for an afternoon snack.

White bowl with iron fortified cereal
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Symptoms of Iron Deficiency

Deficiency is most likely to occur in children and premenopausal women.  Poor diet, malabsorptive disorders, and blood loss can also increase your risk of deficiency. In developing countries, this blood loss can often be the result of intestinal parasites.

In developed countries, blood loss is sometimes a result of poor GI health or injury.

Iron deficiency can be progressive among a few phases:

Mild deficiency leads to a depletion of your iron stores. In this stage, you may not have any outward symptoms, but blood work can reveal low serum ferritin concentrations, and your bone marrow will have low iron stores.

Marginal deficiency (or mild functional deficiency) can lead to decreased production of red blood cells. Blood work will reveal low transferrin saturation, but hemoglobin levels will still be normal.

Finally, we have iron-deficiency anemia.  Hematocrit and hemoglobin levels are low. Your red blood cells are small and lack their normal color. 

Symptoms of iron deficiency anemia include fatigue, weakness, difficulty concentrating, brain fog, decreased immune system function, reduced work and exercise performance, difficulty regulating body temperature, and gastrointestinal distress.

In children, iron-deficiency anemia can lead to learning disabilities that follow them into adulthood.

Conditions that increase iron needs

Frequent blood donations can deplete your iron stores. Those that donate every 8 weeks should aim to increase their intake. 

Heavy menstrual bleeding, cancer (all, but particularly colon cancer), heart failure, gastrointestinal disorders (Celiac, Crohn’s, ulcerative colitis), and colon or stomach surgery can all cause depletion of iron stores for various reasons.

Many of these patients should aim to increase their intake of this mineral.

Various beans in large bags.
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Treatments for iron deficiency

Treatment for a deficiency depends on the severity. Mild deficiency can be corrected by changes in the diet or oral supplementation.  Adding a source of vitamin c with iron-containing foods can increase absorption.

Avoid drinking black tea with meals, as this can decrease absorption.

If the deficiency is secondary to another cause, treatment of that condition can replete your iron stores.

In severe cases, or in cases where the cause of deficiency cannot be reversed, you may require IV iron infusions or blood transfusions.

Symptoms of iron toxicity

Toxicity is not common. However, taking large doses of an iron supplement on an empty stomach can cause constipation, abdominal pain, nausea, vomiting, and faintness.

A genetic condition called hemochromatosis causes an excessive build-up of iron in the body. Symptoms of toxicity typically present in the person’s early 30s and include liver cirrhosis, liver cancer, heart disease, and reduced functioning of the pancreas.

These patients should avoid all supplements that contain iron and vitamin C.

oranges on white table
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Treatment for toxicity

Hemochromatosis is treated with periodic chelation of iron in the blood or blood draws. Chelation is a medication that binds to the iron in your blood and removes it. Alternatively, blood removal (similar to a blood donation) to remove excess iron from the bloodstream is effective.

Should I take a supplement?

Those with chronic anemia, heavy menstrual cycles, kidney or heart failure, or cancer should talk to their doctor about their need for a supplement.

Please note that supplementation can interfere with many other medications, including Levodopa (for Parkinson’s) and Levothyroxine (for thyroid disease). Additionally, certain heartburn medications can reduce the absorption of iron.

Those with hemochromatosis should actively avoid supplementation with iron.

avocado, lentil, and tomato toast on wood background. Lentils are a good source of iron and tomatoes contain vitamin c, increasing absorption.
Photo by Anna Pelzer on Unsplash

What supplementation won’t do

Oral supplementation won’t necessarily treat severe iron deficiency. In addition, if low iron stores are the result of bleeding, supplementing won’t correct the problem.  All underlying medical conditions should be addressed, in addition to supplementation, if needed.

Any concern for the omnivores?

Yes, potentially. While iron deficiency is less likely in omnivores than vegetarians, it is still possible due to low absorption rates, interfering medications, or foods/beverages. 

However, other causes of deficiency and anemia are not directly related to diet and can happen to anyone, regardless of dietary intake.


National Institutes of Health

National Heart, Blood, and Lung Institute

Interested in reading more? Try the other articles in my series!

Vitamin B12



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