Gina Camfield, Associate Nutritionist (ANUTR) AXA PPP healthcare

The health benefits of bananas

7 May 2020

From packed lunch staple, to post work-out snack, breakfast cereal topper and pancake filler – there are many ways we use the under-rated banana to satiate our appetite. But did you know this nutritional powerhouse is loaded with more health-giving good stuff than we might give it credit for?

Bananas have been available to buy in the UK since 1888, when the first consignment arrived through Fyffes (the world’s largest banana producer today). In the UK we eat over 5 billion bananas every year, which is approximately 100 each, give or take (if you include non-banana eaters, other-wise it’s a bit more), so it’s fair to say it’s a fruit-bowl staple in most homes [1]. 

But what is it that makes this shopping-list essential so special in the nutritional stakes? Gina Camfield, Associate Nutritionist (ANutr) at AXA PPP healthcare, highlights some of the health benefits of the humble ‘Gertie Gitana’.*

“Bananas are loaded with nutrients, namely energy-giving carbohydrate and heart-healthy potassium, not to mention fibre, and they count as one of your five a day, so they’re a brilliant go-to. You can even bake them as a sweet treat or put them in cake, making them hugely versatile as part of a balanced diet.”

At 100 calories and less than half a gram of fat in each one, bananas are a nutritious choice that helps you meet your needs for daily veggies and fruit.

Key nutrients in bananas

The amount of nutrients contained in bananas depends very much on banana size, but let’s say we’re talking about a medium-sized banana (118 grams), then it would typically boast the following [2]:

Potassium: 9% of the Recommended Daily Intake (RNI) 

Potassium is one of the most important electrolytes, helping to regulate heart function, as well as control the balance of fluids in the body – a key factor in regulating blood pressure [3]. Electrolytes are involved in many essential processes in your body, conducting nervous impulses, contracting muscles, keeping you hydrated and regulating your body’s pH levels.

Having a banana post-workout or after any physical activity is a great way help replace the potassium you lose during exercise, making them popular with athletes and sportspeople. 

“Combined with the easily digestible carbohydrates they contain, bananas are a favoured fuel after exercise for a lot of people”, says Gina. 

It’s not just after a workout that these powerhouses can offer us benefits to exercise – a banana 30-60 minutes before you exercise can help give a boost of energy and prepare muscles to function at their best.

Vitamin B6: 33% of the RNI  

Vitamin B6, also known as pyridoxine, is one of nature’s mood boosters, partly due to its role in creating neurotransmitters that regulate emotions, including serotonin, dopamine and gamma-aminobutyric acid (GABA). This means it could benefit women who experience premenstrual syndrome, or PMS, including anxiety, depression and irritability [4].

Vitamin B6 also helps our bodies to use and store energy from our food, as well as forming haemoglobin, the substance in red blood cells that carries oxygen around the body [5].

Fibre: 3.1 grams (approx. 10% recommended intake)

Bananas are a great source of dietary fibre, which refers to the parts of plant-based foods that we can’t digest, sometimes referred to as ‘roughage’ or ‘bulk’, and is important in keeping our bowel movements regular and maintaining good digestive health.

There’s strong evidence that eating plenty of fibre is associated with a lower risk of heart disease, stroke, type 2 diabetes and bowel cancer [6].  

In 2015, the government published new guidelines with a recommendation that fibre intake should increase to 30g a day for adults (aged 17 years and over).

Vitamin C: 25% of the RNI 

Vitamin C, also known as ascorbic acid, has several important functions to keep us well, which includes [7]:

  • Helping to protect cells and keeps them healthy
  • Maintaining healthy skin, blood vessels, bones and cartilage
  • Helping with wound healing

Magnesium: 11% of the RNI

Magnesium is a mineral that performs many tasks around the body. It helps with muscle and nerve function, regulating blood pressure, and supporting the immune system. It also helps turn the food we eat into energy, as well as make sure the parathyroid glands, which produce vital hormones for bone health, work efficiently.

Copper: 8% of the RNI

Copper, another essential mineral, helps to produce red and white blood cells and trigger the release of iron to form haemoglobin, the substance that carries oxygen around the body.

According to the Copper Alliance , Copper is also essential for:

  • Brain development during foetal and post-natal growth, and maintenance of brain health throughout life
  • Efficient communication between nerve cells
  • Maintenance of healthy skin and connective tissue
  • Wound healing
  • Structural integrity and function of heart and blood vessels, and growth of new blood vessels
  • Proper structure and function of circulating blood cells
  • Maintenance of a healthy and effective immune response
  • Generation and storage of energy in the ‘power plants’ of our cells, the mitochondria.

Manganese: 19% of the RNI 

Bananas are naturally high in manganese, a mineral that helps make and activate some of the enzymes in the body. Enzymes are proteins that help the body carry out chemical reactions, such as breaking down food.

In particular, it’s been found to help form an antioxidant enzyme called superoxide dismutase (SOD) [8]. Antioxidants shield the body from free radicals, which are molecules that destroy or damage cells in the body.

Protein: 1.3 grams 

Protein is perhaps an essential macronutrient you weren’t expecting to hear when we talk about bananas, which is important for building and maintaining all types of body tissue, including muscle. 

Eating a banana can help you on your way to hitting your protein target – especially after a workout! The fibres in our muscles tear slightly when we exercise, so we need protein to help knit these back together.

Recommended Nutrient Intake (RNI) for protein is 0.75g per kg of body weight for adults, though this will vary depending on individual circumstances.

Myth: People with diabetes shouldn’t eat bananas…

Banana’s form part of a healthy balanced whole-food diet and offer a safe fruit option for those with diabetes. Whilst they contain sugar, they are high in fibre and other nutrients that are important for our health when protecting again heart disease, cancer and some stomach problems.  

Due to their low GI, (Glycemic Index –  a relative ranking of carbohydrate in foods according to how they affect blood glucose levels) bananas provide a slow release of energy and therefore make a healthy choice when looking to  achieve good blood glucose control [9].

‘Ave a banana! Top ways you might like to use your bananas

  • Add sliced banana to porridge and honey
  • Add slices and spread on top of peanut butter on toast for breakfast or a mid-morning snack
  • Bake in the oven, and then top with honey and ice cream (or Greek Yogurt)
  • Freeze and keep to pop into a fruit smoothie
  • Make banana and raspberry pancakes
  • Make Banana ice cream

*Cockney rhyming slang for banana

RNI = Reference Nutrient Intake (the amount of a nutrient required to meet the needs of 97.5% of the population). All RNI percentages reported are based on a female aged 19+ and have been calculated against Dietary Reference Values for Food Energy and Nutrients for the United Kingdom.

References

[1] Fairtrade, Top facts about Fairtrade bananas

[2] U.S. Department of Agriculture, Nutritional values of medium sized banana

[3] NHS, Potassium

[4] Wyatt et al. Efficacy of vitamin B-6 in the treatment of premenstrual syndrome: systematic review. BMJ, May 1999.

[5] NHS, Vitamin B

[6] NHS, How to get more fibre into your diet

[7] NHS, Vitamin C

[8] Chang Li et al., The Role of Manganese Superoxide Dismutase in Inflammation Defence. 2011.

[9] Glycemic Index Foundation, About Glycemmic Index

Department of Health, Dietary Reference Values for Food Energy and Nutrients for the United Kingdom, HMSO, 1991.

Other sources of information:

Diabetes UK – Myths and FAQS