What’s the upper safe dosage of iron from supplements?

maximum safe dosage for iron

The upper safe dose of iron is 45 mg for adults. Excess iron from supplements can cause severe adverse effects. Hence, we should prefer getting the recommended dose from food. In fact, eating foods rich in iron won’t cause iron toxicity.

What does iron do to the body?

Iron is an essential trace element. We have to eat foods with iron. The body can’t synthesize it.

Above all, iron is an essential component of hemoglobin. This protein is found in red blood cells, and it’s involved in oxygen transfer from the lungs to the tissues. Actually, iron supports muscle metabolism and healthy connective tissue.

Moreover, iron is also crucial for energy metabolism, cellular functioning, physical growth, neurological development, and synthesis of neurotransmitters, hormones, amino acids, and collagen.[1,2]

Although, iron is crucial for health, its deficiency is the most common nutritional deficiency worldwide. In fact, iron deficiency may cause gastrointestinal disturbances, impaired cognition, weakened immune function, fatigue, and low body temperature.

Also, iron deficiency may cause manganese toxicity. Too much manganese may cause adverse effects.

Furthermore, iron deficiency during pregnancy increases the risk of premature delivery, and miscarriage.[3]

The human body recycles iron. But, we lose a certain amount of iron every day, which we have to replenish.

The recommended daily intake of iron is 8 mg and 18 mg for men and women, respectively.

We lose only small amounts of iron in urine, feces, the gastrointestinal tract, and skin every day. But, women lose more iron during menstruation period, due to blood loss.

Pregnant women need even higher dosages. They require 27 mg of iron a day!

Hence, many women take iron supplements.

What’s ferritin?

Most iron in the body is found in hemoglobin. Much of the remaining iron is stored in the form of ferritin in the liver, spleen, and bone marrow. Also, it’s located in myoglobin in muscle tissue.

In fact, ferritin is a blood protein which contains iron. Thus, serum ferritin concentration is a measure of the body’s iron stores. It’s a common test for diagnosing iron deficiency.

What’s the upper safe dosage of iron from supplements?

There is a wide variety of iron supplements, with different iron forms and dosages.

But, high doses of iron may cause adverse effects. Even be dangerous for our health.

Hence, the Food and Nutrition Board has established an upper safe dosage of iron. The upper safe dosage of iron is 45 mg a day, both for women and men.

But, there are iron supplements, providing up to 65 mg of iron per tablet. This dose is 360% of the recommended daily intake and 140% of the upper safe dose!

Only people with health problems, or people who need to replenish their iron stores, may need higher doses than the upper safe. In any case, you should consult your physician before taking iron supplements.

Adverse effects of high dosages.

Higher doses than the recommended can lead to gastric upset, constipation, diarrhea, nausea, abdominal pain, and vomiting.

Furthermore, extremely high doses of iron may reduce zinc absorption, leading to zinc deficiency!

Iron toxicity may occur due to high doses of iron from supplements. Food is unlikely to cause toxicity. The body can control iron absorption from dietary sources.

In fact, excess iron can form free radicals, leading to oxidative stress and tissue damage.[4]

Transferrin is a protein in blood that binds to iron and transports it safely throughout the body. But, too much iron may exist in its free form, damaging cell proteins and membranes by free radical formation. Additionally, the free form of iron can stimulate growth of pathogens!

Do I need iron supplements?

It’s estimated that between 14% to 18% of Americans take a supplement containing iron. But, are iron supplements necessary?

Actually, iron deficiency is pretty common. Young children, women of reproductive age, and pregnant women have higher risk of iron deficiency. Poor diet is the main reason, though.

Hence, most healthy people could increase their iron levels through a well-balanced diet. Only people with health problem may need iron supplements.

Certainly, you should consult your physician before taking any supplement, or drastically changing your diet.

Can I get high doses of iron from food?

Actually, it’s rather unlikely to get more iron than the upper safe dose from food.

Animal-based food sources, such as meat, fish, and egg, have the highest bioavailability, as compared to plant-based foods.

Actually, only beef liver and oysters are particularly rich in iron. But, people don’t eat them regularly. Moreover, you should avoid eating beef liver, due to the increased risk of vitamin A toxicity.

On the other hand, iron in plant-based foods is less bioavailable. We can’t possibly exceed the maximum safe dose by following a plant-based diet. In fact, vegans and vegetarians should get 1.8 times more iron from food than meat-eaters!

Foods rich in iron are meat, eggs, poultry, fish, whole cereals, legumes, fruits, vegetables, potatoes, and dark chocolate. Also, you could boost your daily iron intake, drinking certain fruit juices!

How could I increase iron absorption?

Consuming a wide variety of foods rich in iron is good for increasing your iron intake. But, you should avoid certain foods in order to increase iron absorption!

First, you shouldn’t drink coffee, tea, or red wine when consuming foods rich in iron. These beverages contain polyphenols. These compounds bind to iron in the intestine, inhibiting its absorption.

Moreover, we should avoid drinking milk or consuming other dairy when we eat foods high in iron. Calcium significantly inhibits iron absorption as well.

Certain animal proteins such as milk proteins (casein, whey), and egg proteins may inhibit iron absorption as well.

On the contrary, meat, and fish contain a peptide known as MFP Factor, which enhances the absorption of iron. In fact, combining beef, chicken, or fish with plant-based foods rich in iron can increase iron absorption by 2-3 fold!

Additionally, vitamin C significantly enhances iron absorption. Thus, you could benefit from eating foods rich in vitamin C, such as broccoli, cauliflower, pepper, tomato, and lemon juice with foods rich in iron!

Last, but not least, honey might increase iron levels by 20%, although it has negligible amounts of iron!