Iron Absorption: How Your Genes Influence Your Needs

In this article we will try to understand how genes influence how we absorb iron differently.

Read on to learn how to make your genes work for you and get pro-tips on how you can improve iron absorption in your body.

Why Do We Need Iron?

Iron is an essential mineral that performs several crucial roles within the human body, further underscoring its importance:

Oxygen Transport

The primary role of iron in the human body is in the formation of hemoglobin, a protein found in red blood cells.

Hemoglobin binds to oxygen in the lungs and transports it to all other parts of the body where it’s needed for various metabolic reactions.

Without sufficient iron, hemoglobin synthesis is impacted, resulting in a lack of oxygen delivery to tissues and organs.

Energy Production

Iron plays a role in cellular energy production. It is a component of cytochromes, proteins that are involved in the electron transport chain within the mitochondria – the cell’s powerhouse.

In this role, iron is vital for the production of ATP, the main energy currency of the body.

DNA Synthesis

Iron is essential for DNA synthesis because it serves as a cofactor for ribonucleotide reductase, an enzyme that is crucial in DNA replication and repair.

Immune Function

Iron is required for a healthy immune system.

It is involved in the proliferation and maturation of immune cells, especially lymphocytes, which contribute to the immune response.

Neurological Development

Iron is important for normal neurological development during infancy and childhood.

It is involved in the synthesis of neurotransmitters, like dopamine and serotonin, which play significant roles in behavior and cognition.

Given the vital roles that iron plays, it’s clear why maintaining adequate iron levels is essential.

It’s important to have balanced iron levels as both deficiency and excess can lead to serious health complications.

Deficiency can cause anemia and impact cognitive development in children, while excess can lead to iron overload disorders such as hemochromatosis.

History Of Iron In Human Health

The understanding of iron’s importance in human health has a long history.

Ancient Egyptians and Greeks recognized iron’s health benefits, often using iron-rich clay and wine concoctions to treat iron deficiency. I

n the 19th century, the relationship between iron and hemoglobin formation was discovered, and the link to anemia was identified.

Further research in the 20th century revealed iron’s multifaceted roles in human health and disease.

RDA Of Iron

The Recommended Dietary Allowance (RDA) for iron varies depending on age, sex, and life stage.

For adult men, the RDA is 8 mg/day, and for adult women aged 19-50, it’s 18 mg/day.

Pregnant women require more iron (27 mg/day) due to the increased blood volume and fetal needs.

Genetics Of Iron Requirements

Iron metabolism in our bodies is a complex process involving various genes and proteins.

Certain genetic variations can affect how our body metabolizes and uses iron, potentially leading to disorders of iron deficiency or overload.

Key genes involved in iron metabolism include:

HFE

The HFE gene produces a protein that plays a critical role in regulating the amount of iron absorbed from food.

Mutations in this gene can cause hereditary hemochromatosis, a condition characterized by iron overload.

The most common mutations are C282Y and H63D.

TF

The TF gene is responsible for coding transferrin, a protein that binds to iron and transports it throughout the body.

Variations in this gene can affect iron levels and the risk of developing conditions related to iron metabolism.

TMPRSS6

This gene helps regulate hepcidin, a hormone that plays a central role in controlling iron absorption and distribution in the body.

Variations in TMPRSS6 can affect iron status.

SLC40A1

This gene codes for the protein ferroportin, the only known cellular iron exporter in humans. Mutations in SLC40A1 can lead to conditions like ferroportin disease, an iron overload disorder.

SLC11A2

This gene codes for Divalent Metal Transporter 1 (DMT1), which is responsible for transporting iron from the diet into body cells.

Mutations in SLC11A2 can cause iron-refractory iron deficiency anemia, a condition characterized by anemia that is unresponsive to oral iron supplementation.

HAMP

This gene codes for hepcidin, the central regulator of iron homeostasis.

Abnormalities in HAMP can lead to imbalances in iron metabolism, causing disorders like hemochromatosis.

A table summarizing some of the key single nucleotide polymorphisms (SNPs) associated with genes involved in iron metabolism:

Gene	SNP	Associated Condition
HFE	rs1800562 (C282Y)	Hereditary hemochromatosis
HFE	rs1799945 (H63D)	Hereditary hemochromatosis
TF	rs3811647	Altered iron levels
TMPRSS6	rs4820268	Iron deficiency anemia
SLC40A1	rs11568350	Altered iron levels, ferroportin disease
SLC11A2	rs407135	Iron-refractory iron deficiency anemia
HAMP	rs10421768	Hereditary hemochromatosis

Please note that while these SNPs have been associated with changes in iron metabolism and related conditions, they do not guarantee that an individual will develop these conditions.

Other factors, such as additional genetic variants, environmental factors, and lifestyle choices, also play a role.

DISCLAIMER: Always consult with a healthcare provider or a genetic counselor for personalized advice based on your genetic data.

Section Summary

It’s important to note that iron levels are not solely determined by genetics. Various non-genetic factors, such as diet, certain diseases, and life stage, can also significantly influence iron metabolism and requirements. Always consult with a healthcare provider to understand your iron requirements better.

Non-Genetic Factors That Influence Iron Requirements

Several non-genetic factors can influence iron requirements, including diet, age, physiological status (pregnancy, lactation), and health conditions (bleeding disorders, certain infections, and diseases).

For example, vegetarians might need more dietary iron than non-vegetarians due to the lower absorption of non-heme iron found in plants.

Effects Of Iron Deficiency

Iron deficiency can result in anemia, characterized by symptoms like fatigue, weakness, pale skin, and shortness of breath.

It can also affect immune function, cognitive performance, and temperature regulation.

Effects Of Excess Iron

Conversely, iron overload can be harmful, leading to conditions like hemochromatosis.

Excess iron can deposit in tissues, leading to organ damage, particularly in the heart and liver.

Symptoms include fatigue, joint pain, abdominal pain, and loss of libido.

How To Eat An Iron-Rich Diet?

Adopting an iron-rich diet involves incorporating various foods high in iron into your daily meals.

Here are some examples of iron-rich foods and ideas for incorporating them into your diet:

1. Lean Meats: Lean meats like chicken, beef, and turkey are rich in heme iron, which is more easily absorbed by the body. You can grill or bake lean meat and serve it with a side of vegetables or make it a filling for sandwiches and wraps.
2. Seafood: Seafood like oysters, clams, and tuna are excellent sources of heme iron. Try making a seafood stew or grilling fish for a healthy, iron-rich meal.
3. Spinach: Spinach is high in non-heme iron. You can use spinach in salads, sautés, smoothies, or pasta dishes. For a quick meal, sauté spinach with garlic and olive oil and toss with cooked pasta.
4. Legumes: Foods like lentils, chickpeas, and black beans are rich in iron. Try making a lentil soup or a chickpea salad. You could also prepare a bean chili or include beans in tacos or burritos.
5. Fortified Cereals and Breads: Choose cereals, breads, and pasta that are fortified with iron. These can serve as a base for various meals – for example, avocado toast on iron-fortified bread or a bowl of iron-fortified cereal with a handful of berries.
6. Quinoa: Quinoa is a gluten-free grain that is a good source of iron. You can make a quinoa salad with mixed vegetables, use it as a base for a grain bowl, or incorporate it into a stir-fry.
7. Tofu: Tofu is a good source of non-heme iron and can be used in a variety of dishes. You can stir-fry it with vegetables, add it to soups, or grill it and serve it with a dipping sauce.

PRO-TIP: Remember, consuming iron-rich foods alongside vitamin C-rich foods can help increase the absorption of non-heme iron. For example, squeeze a lemon over your spinach salad or enjoy a glass of orange juice with your fortified breakfast cereal.

Please consult a registered dietitian or healthcare provider for personalized advice.

These are general suggestions and may not be suitable for everyone, especially for those with certain health conditions or dietary restrictions.

Conclusion

Iron is vital for human health, influencing several physiological processes.

While genetic factors can impact iron needs, non-genetic factors like diet and health status are equally influential.

Both iron deficiency and excess can lead to health issues.

Therefore, a balanced intake of iron, ideally from dietary sources, is crucial for optimal health.

Reference

1. Institute of Medicine (US) Panel on Micronutrients. “Dietary Reference Intakes for Vitamin A, Vitamin K, Arsenic, Boron, Chromium, Copper, Iodine, Iron, Manganese, Molybdenum, Nickel, Silicon, Vanadium, and Zinc.” Washington (DC): National Academies Press (US); 2001.
2. Ganz T. “Systemic iron homeostasis.” Physiological reviews. 2013;93(4):1721-41.
3. Hurrell R, Egli I. “Iron bioavailability and dietary reference values.” The American Journal of clinical nutrition. 2010;91(5):1461S-1467S.