Do Bananas Have Iron?

Overview

In short, yes they do, however, bananas are considered a rather poor source of dietary iron. While the established recommended daily dose of iron among sexes and ages is approximately 18 mg, one portion of banana contains around 0.4 mg of iron (only 2% of recommended daily iron intake for adults).¹  Unlike adults, babies under 6 months of age only require around 0.27 mg of iron, therefore the puree of one banana makes an iron-sufficient and nutritious baby meal. 

Bananas are rather high in carbohydrates and natural sugars, therefore excessive consumption of bananas to reach daily iron intake is not recommended. However, this should not discourage anyone from including bananas in their diet, since each yellow fruit contains plenty of other essential minerals and vitamins, such as potassium, manganese, copper, vitamins B, vitamin A and vitamin C. 

Interestingly, bananas are a fair source of vitamin C, a mineral that enhances iron absorption. Pairing bananas with other iron-rich foods is a great way to boost iron absorption.

Foods Rich in Iron

Dietary iron can be found in two forms: haem iron, which comes from animal haemoglobin and myoglobin,  and non-haem iron, which is found in both animal and plant sources. Uptake of haem iron occurs much more easily (15-35%), compared to that of non-haem iron (<10%).³  This is because, in its independent form, iron reacts with other substances in the digestive tract, and its absorption is fully determined by the balance between iron uptake enhancers and inhibitors.⁵ 

Plant-based diets usually contain high amounts of iron-binding acids (phytate), phenolic compounds, and calcium, which suppress iron absorption of iron in animals. Accompanying iron-rich foods with absorption enhancement, such as ascorbic acid (vitamin C), meats, seafood and poultry will help to enhance iron bioavailability (how well iron can be obtained from food).⁶

According to the US Department of Agriculture (USDA), rich sources of iron include:

• Fortified breakfast cereals - 1 serving containing 18 mg of iron (100% of the recommended intake)
• Seafood - 85 grams containing 8 mg of iron (44% of the recommended intake)
• Canned white beans - 1 cup containing 8 mg of iron (44% of the recommended intake)
• Liver - 3 ounces containing 5 mg of iron (28 % of the recommended intake)
• Spinach -  ½ cup containing 3 mg of iron (17% of the recommended intake)
• Tofu - ½ cup containing 3 mg of iron (17% of the recommended intake)
• Red kidney beans, edamame beans and chickpeas  -  ½ cup containing 2 mg of iron (11% of the recommended intake)
• Green peas -  ½ cup containing 1 mg of iron (6% of the recommended intake)
• Bread - 1 slice containing 1 mg of iron (6% of the recommended intake)
• Mixed nuts -  ¼ cup  containing 1 mg of iron (6% of the recommended intake)

How Much Iron is in a Banana?

Bananas, like most fruits, contain modest iron levels  - The USDA's National Nutrient Database reports a range from 0.2-0.4 mg of dietary iron in bananas.¹⁰  This is insufficient to meet the daily iron requirement of an average adult.  However, bananas are naturally filled with a number of other beneficial minerals and nutrients. Adequate consumption of bananas, along with other iron-dense foods can help to meet your iron requirements. Interestingly, there is no difference in iron levels between green and ripe bananas, and only a very marginal difference associated with raw and dried fruit.²

Is that More Than Other Fruit?

The iron content of bananas is rather poor when compared to other fruits and vegetables.⁷ For instance, while bananas contain a marginal 1% of daily iron intake per 100 g, it is much higher for tamarinds (16%), persimmons (14%), rowal (12%), blueberries (12%), mulberries (10%), grapefruit (9%) and hibiscus (8%). Importantly, these iron-rich fruits and berries are also high in antioxidants and packed with iron absorption-enhancing vitamin C.⁷

What Other Important Nutrients are in Bananas?

Bananas are an excellent source of various minerals, importantly potassium (1 medium-sized banana provides 23% of daily potassium requirement), copper, manganese, phosphorus, selenium along with various vitamins (vitamin A, vitamin B₆, vitamin C, vitamin D), fibre and carbohydrates.⁸

A single serving of banana provides 41% of daily vitamin B₆, helping to maintain the appropriate functioning of the immune system, and supporting the function of the nervous system and memory. It also helps to balance blood glucose levels and maintain heart health.

Ripe bananas are rich in energy (116 Kcal per 100 g), two bananas were found to be sufficient to fuel an average individual for a 90-minute workout.⁸

How Much Iron do you Need Per Day?

According to the U.S. Food and Drug Administration (FDA), the mean estimate of the daily dietary requirement for iron across genders and biological sexes is 18 mg/day. While newborns and infants require much less (around 0.27 mg/day), teenagers and adults require anywhere from 9 mg/day to 14.8 mg/day of iron.⁴  Menstruating women are particularly at risk of suffering iron deficiency anaemia. 

It might come as a surprise, however, around 90% of our required daily iron comes from our own metabolism, more specifically from iron recycling during the breakdown of red blood cells. These are blood cells that contain iron-bound heme groups which allow them to carry oxygen throughout the body. Our bodies learned to minimise iron losses and there is no mechanism for removing iron from the body. 

Despite this adaptation, a relatively small amount (approximately 1 mg/day) of iron is lost from epithelial tissues, such as skin, the genitourinary tract, and the gastrointestinal tract and must be replenished with dietary iron supply.³ Iron levels in humans are balanced mainly by the ability to absorb iron from the diet. Various food additives affect iron absorption, for example, vitamin C enhances its absorption, while calcium inhibits iron uptake.   

Why Do We Need Iron?

Iron is a mineral essential for the function of numerous proteins, most importantly a key protein found in red blood cells called haemoglobin. Red blood cells ensure the transport of oxygen throughout the body to maintain body functions. Iron is literally the core of correctly structured and functional haemoglobin; it is needed to bind and carry oxygen. 

Additionally, around 25% of iron is stored in an iron-containing protein called ferritin. Ferritin stores iron in the body and releases it when needed. A consistently low dietary iron intake can result in depleted ferritin stores. Also, iron is essential to maintain a healthy functioning immune system.⁵  Consequences of inadequate iron intake include serious health complications.

Iron-Deficiency Anaemia

Iron-deficiency anaemia is a condition caused by a deficiency of functional red blood cells and their associated oxygen-carrying function due to long-term impaired iron levels.¹¹  The onset of anaemia due to iron deficiency is gradual, however, the identifiable consequences only occur once iron levels are critically low.

Complications include disrupted physical performance, decreased maximal oxygen consumption of the muscles and impaired exercise endurance. Physiological problems arise from inadequate oxygen delivery to the muscles and associated disruption to biochemical processes within the tissues. Along with physical decline, there is significant cognitive impairment and mental decline.

An important cause of iron-deficiency anaemia is a dietary deficiency — this takes approximately 8 years for an average adult to progress to iron deficiency anaemia due to a poor diet, or iron malabsorption.¹¹

Importance of B Vitamins

There is a strong link between iron, vitamin B₁₂ and folate; healthy levels of B₁₂ are key to maintaining sufficient iron levels. ⁹

Vitamin B₁₂ supports healthy levels of iron in the body by activating a protein, methionine synthase, that in turn helps our bodies to utilise folate (vitamin B₉), which is needed to produce RNA and DNA molecules during cell division. When vitamin B₁₂ levels are low, there is a gradual decrease in usable folate, resulting in an inability to produce new red blood cells, which only last about 110 days. This depletion of red blood cells disrupts adequate oxygen transport and supply to the tissues. Eventually, this inability to replace ageing red blood cells with new ones will lead to deficient levels of iron in the blood. ⁶ 

Disrupted vitamin B₁₂ supply can cause pernicious anaemia  (different from previously discussed iron-deficiency anaemia), which leads to low levels of iron and significantly depleted circulating red blood cells. The recommended dose of vitamin B₁₂ is about 2.4 mg per day, which is mostly derived through a healthy animal-based diet.⁹  Vegans and those who do not consume animal-source foods are at higher risk of B₁₂ deficiency, although there are remedies for this.  Interestingly, although bananas are not particularly packed with readily-available iron, yellow fruits are rich in folate (one banana contains 19% of folate daily requirement).⁸ This indirectly contributes to the maintenance of healthy iron levels.

Summary

Bananas are healthy, nutrient-rich fruits, which can be introduced into a healthy balanced diet to indirectly boost your iron levels and maintain healthy immunity, brain and muscle function. However, they are not an intrinsically good source of iron.