Do Beets Have Iron?

Introduction

The beetroot is a tap root belonging to the beetroot plant, Beta vulgaris. The vegetable is grown for its edible taproots and leaves (beet greens). It is also known as garden beet or table beet. Other subspecies of the plant include sugar beet, a leafy vegetable known as chard or spinach beet and mangel-wurzel, a crop used to feed livestock. Beetroots have a variety of nutritional benefits. They have been studied for their antioxidant and anti-inflammatory effects, anti-cancerous, anti-diabetic, liver-protective and wound-healing properties, and their ability to lower blood pressure.^1,2,3  

Nutritional profile

Beetroots have a diverse range of phytochemicals (chemicals from plants that are not essential nutrients but are beneficial to health). Some of these include betalains, flavonoids, polyphenols, saponins and inorganic nitrate (NO₃), all of which have protective properties against diseases.⁴ They also have a rich source of minerals, including potassium, sodium, phosphorous, calcium, magnesium, copper, iron, zinc and manganese.⁵

The nutritional composition of raw beetroot and its other consumption methods (per 100g or L) are listed in the table below:⁶ 

^a As mg gallic acid equivalent (GAE)/ 100 g; ^b as mg rutin equivalent (RE)/100 g sample

Iron requirement

Iron is an essential nutrient for metabolism, and its medicinal properties have been traced back to as early as the Egyptians, Hindus, Greeks, and Romans.⁷ It is recommended that the daily intake of iron for men (over 18) is 8.7 mg, for women (18-50 years) is 14.8 mg, and for women (over 50), it is 8.7 mg.⁸   

Functions of iron

In the human body, iron is not freely available as it is usually bound to proteins and requires a high amount of energy to unbind. Around 70% of the body’s iron is found in blood and muscle, 25% is stored as ferritin (a blood protein), and 6% is a component of proteins involved in metabolism.⁹ In blood, iron is a functional component and exists as a complex form where the element itself is bound to the proteins in a blood cell (haemoglobin).¹⁰ The iron in the blood cells helps transport oxygen from the lungs to the other tissues in the body. Iron is also bound to the muscle (myoglobin) and helps in oxygen production, muscle metabolism and healthy tissue growth via collagen production. Iron further plays important metabolic roles in neurological development (especially in neurotransmitter production), immunity, and synthesis of certain hormones.^11,12 

Deficiency

On average, an adult male has 1000 mg (enough for approximately three years), and an adult female has 300 mg (enough for approximately six months) of iron levels in storage.¹³ When dietary intake of iron is low, the stores are slowly depleted, especially in the blood and muscles. Depletion of iron levels can result in anaemia, where there is a lack of healthy blood cells to carry enough oxygen around the body. Serum ferritin (a blood protein) is an indication of anaemia. Ferritin levels are <12 μg/L for <5 years of age and <15 μg/L for >5 years of age when iron stores are depleted.¹⁴ 

The symptoms of anaemia are:⁹

Iron content of beets and beet greens

A cup of beets (approximately 136 g) contains 1.1 mg of iron, which is around 6% of the daily recommended intake for this mineral.¹⁵ Moreover, one cup of beet greens (approximately 36 g) contains 0.95 g of iron.¹⁶ 

Beets in the formation of red blood cells

Studies using an anaemia disease model have shown that the beetroot’s antioxidant potential can protect against the development of anaemia caused by oxidative stress and agents that break down blood.¹⁷ Alongside iron, beetroots naturally have a very high level of folic acid (also known as vitamin B12 or B9). Iron in conjunction with folic acid is required when the bone marrow produces new red blood cells.^18,19

Absorption of iron

Iron is absorbed in the sites called the duodenum and upper jejunum in the small intestine. It is then transferred across the intestinal walls into the blood, where it is further transported by a blood protein (transferrin) to the cells (for metabolic functions) or the bone marrow (to produce new blood cells). Most dietary iron occurs in a ferric form (Fe⁺³). The acidic environment of the gut, along with an enzyme called ferric reductase, changes the ferric form to a ferrous ion (Fe⁺²), which enables easier absorption. 

Iron in the diet can occur in two categories: heme iron - either from haemoglobin or myoglobin via the consumption of meat, poultry and fish, or non-heme iron - from cereals, pulses, legumes, fruits, and vegetables. The amount of iron absorbed in the gut is low, approximately 2 mg, and ranges from 5% to 35% depending on the type of iron.^7,20 Heme iron is easily absorbed (15%-35%), and very few dietary factors affect its absorption rate.⁹ On the contrary, non-heme iron absorption is much lower (2%-20%) as they are loaded with iron blockers which prevent absorption and are strongly influenced by dietary factors.⁹ However, non-heme iron contributes to a better quality of iron nutrition than heme iron would.⁹

Beets and Vitamin C

Studies have shown that vitamin C can increase the absorption efficiency of iron.²¹ Particularly with non-heme iron, vitamin C (also known as ascorbic acid) has to ability to reduce iron from its ferric (Fe⁺³) to ferrous state (Fe⁺²), where it is easily absorbed. Additionally, vitamin C can chelate iron, which means it can bind to it, increasing its chances of absorption. In another study, researchers have shown that a daily intake of 100 mg of vitamin C increased iron absorption by 67%.²² The daily recommended amount of vitamin C is 40 mg per day, and a cup of beetroots (138 g) provides 16% of that intake.^23,24 

Health benefits

Beetroot Lowers Blood Pressure and Oxidative Stress

Beetroots contain high levels of nitrates (NO₃). Nitrates have a hypotensive effect (lowers blood pressure) as they are converted to nitric oxide (NO), which widens the blood vessels (vasodilation) to allow blood to flow freely.⁶ Nitric oxide also has the ability to decrease reactive oxygen species (ROS) in the blood. These are molecules that damage cellular structures by oxidative stress.⁶ The antioxidant properties of beetroots remove ROS, improving overall cell function. 

Beetroot Promotes A Healthy Balance Of Glucose And Insulin

Nitrates found in beetroot can also have a regulatory effect on insulin and glucose.⁶ They promote growth and blood flow in the pancreatic cells, which in turn increases insulin secretion. It simultaneously causes cells to be more sensitive to high levels of glucose, which can regulate the number of carbohydrates digested and the glucose absorbed.

Beetroot Promotes A Healthy Gut Microbiome

The microbiome is an array of bacteria that grows on or in our body.⁶ The ingestion of nitrates via beetroots can affect the bacterial composition in the mouth and gut. It promotes the growth of beneficial digestive bacteria such as Bacteroidetes, Firmicutes and Fusobacteria. Furthermore, it also promotes the growth of NO₃ reducers (which convert NO₃ to NO) such as Neisseria and Rothia, which are helpful in managing blood pressure and improving cardiovascular health. Beetroot also increases dietary fibre intake, which is required for a healthy bowel.

Beetroot Reduces Inflammation

Betalains found in beetroots act as potent anti-inflammatory agents.² They work by disrupting the course of pro-inflammatory molecules in the body. Chronic inflammation is observed in cases of severe immune reactions to diseases and the development of tumours. Studies suggest that the accumulation of betalain extracts may suppress these effects.

Improves Cognitive Function

Decline in cognition is characterised by the lack of blood flow to the brain.² This effect can also lead to many neurological disorders such as brain damage, clinical dementia and Alzheimer’s disease. Blood flow to the brain is also mediated by nitric oxide (NO) activity. It plays a vital role in the delivery of glucose and cell communication in the brain cells. Beetroots are natural nitric oxide generators and promote blood circulation in the brain, thereby reducing the damaging effect of cognitive diseases.

Side effects

Beetroot is usually well tolerated by the majority of its consumers. Beeturia is a benign side effect of beetroot consumption where the colour of urine or stool changes to pink, purple or red. This is caused by the betalain pigments (giving beetroot its red colour) not being broken down during digestion. Beeturia is prevalent in 10-14% of the population.²⁵

Whilst having beetroots can be beneficial, excessive consumption can be detrimental. Beetroots can have some harmful effects on individuals who are:

• Prone to kidney stones: Beetroots have high levels of oxalates, which are molecules that attract minerals such as calcium to produce stones in the kidneys.²⁶
• Anaphylactic: Although rare, there is a possibility that beetroot can trigger an allergic reaction in certain individuals
• Low blood pressure: Beetroots are high in nitrates, which naturally lower blood pressure. While beetroots are beneficial to individuals with high blood pressure, individuals with low blood pressure can be severely affected by their vasodilatory properties.²⁷ 
• Stomach Upsets: The high nitrate content in beetroot can also lead to abdominal cramps in individuals.²⁷ 
• Pregnant: Methemoglobin is a dysfunctional form of haemoglobin in the blood which cannot carry oxygen. Pregnant women are more susceptible to methemoglobin production and high levels of nitrates in beetroot stimulate its production. This can cause symptoms such as lack of energy, headache, dizziness, and blue-grey colouration of skin around the eyes, mouth, lips, hands, and feet.²⁸
• Liver Diseases: Excessive consumption of beetroots can cause metal accumulation in the liver, making it dysfunctional.²⁹    

Ways to add beets to the diet

Beetroots are a versatile vegetable, and there are many ways you can incorporate them into the diet these include:

• Salads: Add raw (peel off the skin) or boiled beets as a colourful and flavourful ingredient to salads!
• Pickled Beetroots: Equally delicious when pickled and had on its own!
• Dip: Make a beetroot dip with blended garlic, spices, beetroots and greek yoghurt!
• Roasted Beetroot: As a healthy and lighter alternative to roasted potatoes!
• Beet Greens: Sauté the beet greens from beetroots in a pan with garlic and olive oil!
• Blended Beetroot: Blend beetroot to make a beetroot juice or add beetroot powder to smoothies.

Other iron-rich foods

Beetroots do not have to be the only method of ingesting iron. A healthy balance of various types of iron-rich meals can increase intake:³⁰

• Meats: Meats, particularly red meat, do not have iron inhibitors. This can make them a valuable source of iron as they are easily digested. The iron-rich sources (highest to lowest) include goose/duck/ pork liver, oysters, caviar (black and red), cuttlefish, whelk, and octopus. 
• Grains: Grains have iron inhibitors such as phytic acid, which decrease overall absorption. The iron-rich sources (highest to lowest) include whole wheat, oats, quinoa, barley, and rye.
• Beans: Beans also contain phytic acid; however, they are a valuable source of iron for meat-free diets. It is also recommended to soak beans in water to reduce phytic acid levels. The iron-rich sources (highest to lowest) include soybeans, winged beans, white beans, lentils, moth beans, kidney beans, chickpeas, yardlong beans, and black-eyed peas.
• Nuts and Seeds: Certain nuts and seeds also contain phytic acids; however, soaking these in water should reduce levels. The iron-rich sources (highest to lowest) include sesame seeds, pumpkin seeds, sunflower seeds, cashews, flax seeds, pine nuts, and hazelnuts.  
• Vegetables: When ingesting vegetables, it is important to pair them correctly with certain beans and grains, as iron inhibitors can negate the effect of iron uptake in vegetables. The iron-rich sources (highest to lowest) include mushrooms, lemon grass, baked potatoes, parsley, horseradish leaves, and spinach.
• Fruits: Fruits that are rich in vitamin C  can help increase iron absorption. The iron-rich sources (highest to lowest) include persimmons, blueberries, mulberries, elderberries, passionfruit, and currants.

Summary

Beetroots are often an underrated vegetable when it comes to their nutritional benefits. While it can be beneficial in iron intake, it is always recommended that a well-balanced meal of meats, grains, fruit and vegetables is eaten to reap the benefits of iron absorption. Knowing the full nutritional profile of foods can be helpful in order to reduce the number of iron inhibitors ingested and to increase the intake of iron-rich sources of food.