A Nutritionist’s Guide to Iron Supplements

Published on April 07, 2022

By Gaia Herbs

Gaia Herbs

Iron is an essential mineral. It plays a role in antioxidant systems and is necessary for the cytochrome enzymes in the liver to process drugs, caffeine, and hormones. About 2/3 of the iron in the body is in the hemoglobin of red blood cells. The remainder is in the liver, spleen, and bone marrow. Without enough iron, the body cannot make hemoglobin, the substance in red blood cells that carries oxygen and delivers it to tissues and cells to produce energy. 

The only way to eliminate iron from the body is through the blood (bleeding). There isn't a way to get rid of excess iron because it is always bound to proteins, and excess iron stores as ferritin in the liver and is re-utilized. The body uses ferritin first when low in dietary iron. 

When too much iron circulates—either supplementary or dietarily—the body stores excess iron in the heart and pancreas (which is not good). It is a delicate balance to consume enough, but not too much, iron every day through a variety of different foods.

Plant-Based Iron vs. Animal-Based Iron vs. Conventional Iron Supplements

Human bodies can absorb iron from food sources above all others, and the phrase, “You are what you eat,” is much more accurate than, “We are what we absorb.” Food-sourced iron is ideal for the body and is easier for the digestive system to process.

Foods that are high in iron include:

  • Red meat (beef, pork, lamb)
  • Organ meats (liver, kidney)
  • Poultry (chicken, turkey)
  • Seafood (clams, oysters, sardines)
  • Beans and legumes (lentils, chickpeas, kidney beans, lima beans
  • Tofu and Tempeh (soybeans)
  • Leafy greens (spinach, Swiss chard, Brussels sprouts)
  • Blackstrap molasses 
  • Dried fruits (dried apricots, prunes, raisins)
  • Whole grains (oatmeal, quinoa, fortified cereals)
  • Seeds (pumpkin seeds, sesame seeds, flax seeds, hemp seeds)

Plant-Based Iron

Plant-based or non-heme iron sources have several benefits over animal-based iron sources. Non-heme iron sources are ideal for those following a vegetarian or vegan diet, as they are entirely free of animal products.

Plant-based iron sources typically have slightly lower iron content per serving than animal-based ones. However, compensating for that is manageable by consuming a wider variety of iron-rich plant foods.

Furthermore, non-heme iron sources are often accompanied by other beneficial nutrients such as fiber, folate, and vitamin C, enhancing iron absorption and providing additional health benefits. Consume non-heme iron sources with foods that are a rich source of vitamin C to maximize absorption.

Animal-Based Iron

Animal-based iron sources are a combination of non-heme and heme iron. Heme iron comes from animal-based foods like red meat and is more bioavailable than non-heme iron from plant-based foods, eggs, and dairy. This type of iron is easily absorbed by the body and readily used for essential functions such as the formation of hemoglobin and myoglobin.

However, the majority of iron intake comes from non-heme iron sources, and the body can regulate the absorption of iron based on its needs. Consuming excessive heme iron may increase the risk of certain health conditions, such as heart disease and certain cancers.*

A balanced and varied diet that includes both heme and non-heme iron sources is ideal. A well-planned diet that consists of a variety of iron sources can help ensure adequate iron intake.

Conventional Iron Supplements

While conventional iron supplements can help address iron deficiency, there may be better choices due to several factors. 

Making conventional iron supplements involves dissolving iron fillings in sulfuric or hydrochloric acids. This process results in a non-soluble form of iron dehydrated into an iron salt, which can be difficult for the body to absorb and utilize effectively.

Although supplemental iron effectively raises iron levels, the body has difficulty digesting single doses of iron salt without the minerals, nutrients, and antioxidants provided by whole food sources. 

Conventional iron supplements typically contain a concentrated dose of iron, often with tablet fillers included, which can lead to adverse effects such as constipation, nausea, and gastrointestinal upset, especially when taken in high doses.

Can You Increase Your Iron Naturally?

Consider alternative sources of iron, such as whole foods and supplements made from food-based sources of iron, that are easier for the body to absorb and utilize effectively.

Increasing iron levels naturally through dietary and lifestyle changes are possible. A diet rich in foods containing good sources of iron can help support iron levels over time.* It is also essential to consume vitamin C-rich foods, such as citrus fruits, bell peppers, and tomatoes, alongside iron-containing foods, as vitamin C can support iron absorption.*

Managing stress, adequate sleep, and regular exercise can support healthy iron levels. However, it is essential to note that individuals with severe iron deficiency may require iron supplementation or medical treatment. Always consult a healthcare professional before significantly changing your diet or lifestyle.

Considering Iron Supplements

There are many reasons for low iron levels. Following a plant-based diet like a vegetarian or vegan diet can sometimes lead to low iron levels because the body does not absorb plant-based sources of iron as well as animal-based ones. 

Some medical conditions can lead to iron malabsorption, resulting in low iron levels.

In some cases, taking an iron supplement may be beneficial to increase iron levels.

What Dosages Are Suggested for Iron Supplements?

The recommended daily iron intake varies by age, gender, and other factors. The following are general guidelines for suggested doses of iron supplements: REF#1252REF#1253

For Women

The recommended dosage for iron supplements for women is higher than for men and children, and this is because women have higher iron requirements due to menstruation and pregnancy.

During menstruation, women lose blood, and thus, iron, from their bodies, which can lead to iron deficiency if iron intake is insufficient. Additionally, a woman's blood volume increases during pregnancy, and she needs more iron to support the growing fetus and placenta. 

Iron deficiency during pregnancy can increase the risk of preterm delivery and low birth weight.*

The recommended daily allowance (RDA) for iron in females is:

  • For teenage girls aged 14 to 18 years: 15 mg per day.
  • For adult women between 19 to 50 years: 18 mg per day.
  • For pregnant women: 27 mg per day.
  • For postmenopausal women: eight mg per day.

For Men

Teenage boys require more iron than adult men because they rapidly grow and develop. During puberty, boys experience increased muscle mass, bone density, and blood volume, all requiring iron. 

Additionally, teenage boys may lose iron through sweating during physical activity, making it vital to consume adequate amounts of iron through their diet or supplements. Once boys reach adulthood, their iron needs decrease as they have completed their growth and development.

The recommended daily allowance (RDA) for iron in males is:

  • For teenage boys aged 14 to 18 years: 11 mg per day. 
  • For adult men aged 18+ years: eight mg per day.

For Children

Infants exclusively breastfed typically do not require iron supplements until around four to six months, as breast milk contains adequate iron for the first few months of life. 

Formula-fed infants may require an iron-fortified formula from birth, as cow's milk does not provide enough iron for infants.

Children who are picky eaters or follow a vegetarian or vegan diet may be at higher risk of iron deficiency and may benefit from iron supplements.

Children aged four to eight years may need more iron due to their rapid growth and development during this stage. As children grow, their bodies typically require more iron to support the production of new red blood cells and to accommodate the increase in muscle mass and overall body size.

The recommended daily allowance (RDA) for iron in children is:

  • For children aged one to three years: seven mg per day.
  • For children aged four to eight years: ten mg per day.
  • For children aged nine to 13 years: eight mg per day.

Experts recommend that iron supplements for children be started only after testing for iron deficiency anemia and under the guidance of a healthcare provider to determine the appropriate dosage of iron supplements for you or your child. Individual iron needs may vary based on overall health, diet, and medical conditions.

Iron supplements for children should also be kept out of reach of children, as they can be toxic in high doses. Too much iron can cause side effects, so following recommended guidelines is vital. 

Calcium Interactions and Risk of Iron Overdose

Calcium can bind with iron in the gastrointestinal tract, forming an insoluble complex that is difficult for the body to absorb. As calcium can inhibit iron absorption, it is best to take iron and calcium supplements at different times of the day.

Consuming foods high in calcium alongside foods high in iron is not usually an issue, as the calcium and iron will be consumed together as part of a meal, and the other components in the meal can help the body absorb the iron. 

Taking too much iron can have serious side effects. Some common side effects of iron overdose include nausea, vomiting, stomach pain, constipation, and diarrhea. These symptoms can be severe, leading to dehydration, electrolyte imbalances, and even hospitalization.REF#1255

In addition, too much iron can lead to iron toxicity or iron poisoning, which can cause organ damage and even death in severe cases. Symptoms of iron toxicity include fatigue, joint pain, headaches, dizziness, shortness of breath, and a metallic taste in the mouth.REF#1255

What Makes Gaia Herbs Plant Force Liquid Iron® Different?

When it comes to iron supplementation, quality, and absorbability are the most vital factors. Plant Force Liquid Iron® utilizes plants and herbs rich in nutrients, antioxidants, and iron to deliver a bioavailable and absorbable iron the body can use. 

The synergistic nutrients of Beetroot, Dandelion, Fennel, Nettle, Parsley, Rice, Sea Buckthorn, Star Anise, and Yellow Dock are blended with water, organic honey, and citric acid to form a delicious sweet orange flavored syrup free of fillers and binders. 

Each 10 mL serving contains 10 mg of elemental (absorbable) iron, and with appropriate daily dosing, it can help to maintain healthy iron levels.* It is non-constipating, easy on the digestive system, and safe for pregnant and breastfeeding women.

Being a liquid, it also provides the extra benefit of adjusting your daily dose to what you need. If you are sensitive to the flavor of iron, you can also add your daily serving to smoothies.

Formulated and blended in North Carolina, Gaia Herbs uses only the highest quality and rigorously tested sources of herbs and nutrients in their formulas. Their Plant Force Liquid Iron is free of pesticides, microbes, and heavy metals. They use DNA testing to make sure that every herb you read on the label is exactly what is inside the bottle. Check your batch of Plant Force Liquid Iron® with Meet Your Herbs.

Nutritionist’s Note: Before you begin supplementing with iron, have your iron levels tested via blood testing to note if you are, in fact, deficient and in need of supplementation, and if so, what dose of iron you would require in supplement form. 

Your healthcare provider will perform a Complete Blood Count (CBC) to conduct this test. They may also recommend testing your Iron Panel (for serum iron, transferrin, total iron binding globulin capacity, and % saturation of your iron transport proteins) and measuring your ferritin (for stored iron). 

After you begin supplementing with iron, have your iron levels re-checked every 3-4 months to note changes in your iron levels. And to know if you need to discontinue use once your iron levels are within a healthy range (and your diet includes a good variety of iron-rich foods daily). 

If you are pregnant, have a medical condition, or take medications, please consult your doctor before using Gaia Herbs Plant Force Liquid Iron®.

Article and Photographs by Lindsay Kluge (@gingertonicbotanicals)

Lindsay Kluge, MS, CNS, LDN, is a clinical herbalist, nutritionist, blogger, teacher, and writer based in Lexington, VA. She is the creative spirit behind Ginger Tonic Botanicals, her wellness and herbal blog where she muses on herbal teas, simple, nutritious recipes, and outdoor adventures to connect more deeply with the plant world. Lindsay spends most of her time teaching nutrition students as adjunct faculty with the Maryland University of Integrative Health. She contributes to research, writing, stories, and herbal-related articles to publications worldwide. Outside of her home office, you’ll find her backpacking the Blue Ridge Mountains with her dog, Gromit, pressing flowers around the fields of her home, rock climbing everywhere she can, and tending a quaint organic vegetable and herb garden. 



  • 1. National Institutes of Health, "Iron", Office of Dietary Supplements. Last updated February 11, 2021. https://ods.od.nih.gov/factsheets/Iron-HealthProfessional/
  • 2. Centers for Disease Control and Prevention, "Iron and Iron Deficiency", Last reviewed February 1, 2021. https://www.cdc.gov/nutrition/infantandtoddlernutrition/vitamins-minerals/iron.html
  • 3. Yuen HW, Becker W, "Iron Toxicity", [Updated 2022 Jun 27]. In: StatPearls [Internet]. Treasure Island (FL): StatPearls Publishing; 2022 Jan. https://www.ncbi.nlm.nih.gov/books/NBK459224/