Iron Content in Strawberries for Anaemia

Introduction

Strawberries may not be the first food you think of when you think of iron-rich food, but they might be a dark horse in terms of topping up your iron intake. Insufficient iron levels can often cause a condition called anaemia. However, there are simple tricks to increase the absorption rate of iron once it has been ingested. In this article, we explore how strawberries can contribute to maintaining sufficient iron levels by enhancing the absorption of iron. 

Strawberries

Strawberries, or Fragaria x ananassa, are small, droplet-shaped berries, and are one of the most popular fruits grown globally. They are known for their sweet taste and characteristic appearance, with seeds on the exterior, usually growing up to around two inches tall. The most common type of strawberries have striking red flesh and yellow seeds.

Other variations include the pineberry, which features white skin with red seeds, and a miniature form, known as “wild” or “European” strawberries, Fragaria Vesca, which also features the standard colours of red and yellow. Strawberries contain a range of vitamins and minerals and therefore offer a multitude of health benefits, including:¹

• Helping wounds heal - vitamin C is one of the prevalent vitamins in strawberries and helps the healing process by aiding connective tissue, such as collagen, to stretch and combine
• Reducing high blood pressure - potassium in strawberries can help maintain healthy blood pressure by relaxing the walls of the blood vessels and helping protect against muscle cramping
• Lowering blood cholesterol - fibre and antioxidants in strawberries can lower cholesterol and contribute to a healthy digestive system

Anaemia

Anaemia is a condition caused by a lack of (or lack of functioning) haemoglobin in the bloodstream.² Haemoglobin is a protein found in red blood cells, produced by the bone marrow, which allows red blood cells to store and transport oxygen around the body.² It is a common condition, estimated to affect approximately a quarter of the population, most commonly affecting young children, pregnant or menstruating women, and is more common in developing nations due to malnourishment (not having enough to eat or drink resulting in a lack of proper nutrition).³ Anaemia can be recognised by symptoms such as:⁴

• Feeling dizzy or lightheaded
• Experiencing shortness of breath
• Having a lack of energy/feeling excessively tired even after substantial sleep 
• Showing pale skin or nail beds 
• Experiencing heart palpitations (having a fast or noticeable heartbeat)

Anaemia is diagnosed by blood tests that assess haemoglobin levels and red blood cell count.

Iron deficiency anaemia

There are several types of anaemia, including folate deficiency (folic acid deficiency) anaemia, vitamin B12 deficiency anaemia, and chronic disease anaemia. However, the most common form, causing almost half of anaemia cases, is iron deficiency anaemia, arising from a lack of iron in the bloodstream. This can be due to:

• An insufficient diet - this is the most common reason. A lack of iron being ingested results in not enough iron being absorbed. Luckily, easy solutions are to increase your iron intake or take iron supplements, which can be found in any pharmacy or health-food shop 
• Blood loss - a sudden reduction of the volume of blood results in a drop in the amount of iron in the body and thus, the concentration of iron in the blood as more is produced 
• Pregnancy and giving birth - both of these require large amounts of iron, thus depleting the body’s natural stores 
• Rapid growth - the increase in size results in an increased amount of iron needed to maintain normal levels, and additional iron is needed to build healthy new cells 

Treatment of iron deficiency anaemia is, in most cases, achieved through incorporating more iron into the diet. This can either be in a natural form by eating more iron-rich foods, or by taking iron supplements, called ferrous fumarate, for around 6 months. When taking these supplements, there are some side effects to be watchful for.

These include nausea (feeling sick), a loss of appetite, stomach discomfort, and unusual bowel movements (diarrhoea or constipation), so many people choose to alter their diets instead. In severe cases, iron deficiency can be treated by blood transfusions when an increase in iron and/or haemoglobin levels is immediately needed, usually only after blood loss. Iron is also important for the production of hormones and the efficiency of the immune system.

The daily recommended iron intake for adults is as follows:

• People assigned male at birth (AMAB) aged 19+: 8.7 mg
• People assigned female at birth (AFAB) aged 19-49: 14.8 mg (People AFAB need more iron than AMAB due to menstruation)
• People AFAB aged 50+: 8.7 mg

Vitamin C and iron absorption

There are two types of iron found in food: haem and non-haem iron.⁵ Haem iron is found in animal products such as red meat, poultry, and fish. Up to 30% of the ingested haeme iron is absorbed, providing a quick and substantial rise in iron levels when ingested. Foods with high haem iron levels include beef mince (2.7 mg per 100 g) and lamb (1.8 mg per 100 g). Non-haem iron is found in plant-based products such as fruit, vegetables, beans, and lentils.

However, only between 2% and 10% of the ingested iron from non-haem sources is absorbed.⁶ This difference in absorption ratio leads to those following a vegan or vegetarian diet often being advised to monitor their iron intake due to insufficient levels or to take gentle iron supplements along with their regular diet.

Vitamin C (also known as ascorbic acid), is an antioxidant found in many fruits and vegetables.⁷ Its functions include helping wounds to heal, strengthening cells, and maintaining healthy body parts such as skin and cartilage. Healthy individuals are recommended to consume 40 mg of vitamin C every day due to the body not being able to store it.

It also can facilitate the absorption ratio of non-haem iron due to the compound it forms with ferric iron (ironIII), which remains soluble in the alkaline pH.⁷ Studies have shown this can increase the absorption rate by up to 7.1%.⁶ Thus, many doctors suggest consuming vitamin C, such as drinking a glass of orange juice, when taking any iron supplements.

How strawberries can fight anaemia

Strawberries contain 0.41 mg of iron and 58.8 mg of vitamin C per 100 g.¹ Due to these levels, it is an excellent addition to the diet of anyone who is iron deficient or anaemic. One cup, or around eight strawberries, provides 3% of the RDI (recommended daily intake) for iron, but with the addition of a strawberry’s vitamin C, this can be even greater.

Although this is still relatively low and not enough to provide a whole day's iron, it is an easy way to top up your iron levels. Strawberries can be eaten in many different forms and can be eaten with little to no preparation. The built-in addition of vitamin C results in less hassle having to prepare and consume two things at once for the maximum absorption ratio. 

Other ways to increase your iron absorption include:

• Cooking meals with iron homeware - this can be in the form of an iron skillet pan, or cooking with an iron dish. Having a source of iron infusing into your food while cooking can hugely increase the amount of iron present in your meals. This is an easy step for those who already cook and requires no preparation
• Taking iron supplements - these can be found in the majority of health food shops or pharmacies, and are a quick and easy way of getting a boost of iron
• Cut down on tea and coffee - these both contain tannins (a type of plant compound) which can lower the amount of iron absorbed when ingested together.⁸ To combat this, you could try to avoid having tea or coffee with your meals or cut out caffeine altogether

Summary

Anaemia, specifically iron-deficiency anaemia, can often be successfully treated by increasing the amount of iron in the patient’s diet. The most effective way is to incorporate more haem iron sources, like red meat, into the diet. For those who don’t eat animal products, good alternatives of non-haem iron include lentils, or lesser iron sources paired with the enhanced iron absorption provided by vitamin C.

Although strawberries have a relatively high iron content compared to other fruits, it is not sufficient to provide an adult with the RDI of iron. Compared to haem iron sources, they contain little iron, but due to the vitamin C present, the iron consumed is enhanced. While this is an easy way to get iron, it is not the most efficient and should be considered additive instead of the “cure”.

It is important to note that the overconsumption of strawberries can lead to an upset stomach or unusual bowel movements, thus, strawberries should not be relied upon as the only source of iron in a healthy diet.