Bananas: The Potassium-Packed Superfood for Heart and Mind

Bananas: The Potassium-Packed Superfood for Heart and Mind

Explore the heart-healthy benefits and mood-boosting properties of bananas, nature's nutrient-packed superfood

Ingredient feature

Bananas have been glorified in Ancient Buddhist texts as the "fruit of paradise," and scientists have speculated that early bananas may have been the very first fruit on the planet! Properly classified, they are a type of berry.

Arabian traders probably gave bananas their name, as banan - Arabic for fingers or finger tips - would have been an appropriate name for pre-modern bananas which were much smaller than the ones we know today.

Those same Arabian traders are credited with transporting them to Africa, where in the 7th century modern bananas began to emerge. This was a positive development, as the new breed was less mealy and full of seeds than its ancient predecessor.

Now a staggering six million hectares worldwide are devoted to the production of over 1,000 different varieties worldwide, but the classic yellow arc we all know and love is called the Cavendish. This ubiquity is largely because they are extremely well suited for longer storage and transportation times. Cavendish bananas are picked green and tend to ripen only after reaching their destination.


Bananas are an incredibly nutrient-dense superfood wrapped in their own convenient carrying case - the peel. Few fruits are as well poised for healthy snacking purposes on the go.

They are classically associated with potassium, a critical electrolyte we need in abundance as a counterpoint to dietary sodium. Unfortunately, this essential mineral is often lacking in the standard American diet, and great food sources like sweet potatoes, mushrooms, avocados, and bananas often get overlooked.

This is something of a tragedy because potassium, in addition to working with sodium to ensure optimal cellular hydration, is great for protecting cardiac function and keeping blood pressure in a healthy range. Potassium deficiency, which easily flies under the radar, can also be a cause of constipation.

But potassium isn’t all that bananas have to offer. They are also good sources of manganese and vitamin C, which work together to produce an extremely powerful antioxidant enzyme called superoxide dismutase. This enzyme has an affinity for the mitochondria, our cellular powerhouses, which are especially prone to oxidative damage as their job is to act like tiny furnaces. Since mitochondria are abundant in most cell types throughout the body, keeping them happy and healthy is important for everything from muscular energy to cognitive function - in fact, it is estimated that each brain cell contains two million mitochondria!

Bananas are also a good source of pyridoxine aka vitamin B6. This B vitamin, like potassium, is important for heart health because it helps break down an amino acid called homocysteine. High levels of homocysteine are strongly associated with cardiovascular disease and therefore watched closely by doctors on routine blood work especially as we get older. Phytosterols in bananas also inhibit cholesterol absorption. Put it all together, and it is appropriate to consider the humble banana a powerful heart food.

Beyond cardiac health, the B6 in bananas is important for mental health. This is because it is needed for the synthesis of serotonin, our ‘calm and blissful’ neurotransmitter, dopamine, our ‘pleasure and reward’ neurotransmitter, and GABA, our ‘chillout’ neurotransmitter. Anyone with mood imbalances, struggles with motivation, or copious stress levels might be assured that just one medium banana offers 25 per cent of our daily recommended B6.

Bananas also function as a natural antacid and may benefit heartburn sufferers. As an added bonus they seem to have the effect of stimulating the cells of the stomach lining to produce more protective mucus. As rich sources of pectin fiber, bananas can be a soothing fallback food to support digestion and healthy elimination.



Green bananas are somewhat different in phytochemistry from their ripe yellow counterparts.

When underripe, bananas offer a great deal of resistant starch- carbohydrates that do not readily break down as they pass through the digestive tract. This soluble fiber might not feed us directly, but it provides welcome nutrition to healthy bacteria in our small and large intestines. In turn, those probiotic strains in the microbiome produce “postbiotics” like short-chain fatty acids that fuel the cells of our colon. In addition to their resistant starch green bananas contain preformed butyrate, a well-known member of the short-chain fatty acid family.

Green bananas have a significantly lower glycemic index than ripe ones and may be a favoured choice among diabetics or anyone looking to keep their blood sugar balanced. As the fruit ripens, the resistant starch is enzymatically converted into sugar.

However, it’s not just the sugars that mature as bananas ripen and turn yellow: enzymes, vitamins, and various phytonutrients all peak when the fruit is ripe. So while there may be some strategy in selecting the color that is right for you, not to mention personal taste preference, as a general policy most of us are best off eating bananas at peak ripeness.

It’s worth keeping in mind that the brown colour of bananas as they go past ripeness is a sign of oxidation; what you are looking at when you see brown is, simply, free radical damage. So generally we want them to be fully ripe but not overripe. If the banana you are considering is yellow with a few brown spots it may just be at the sweet spot of its nutritional prime.


Best Practices

Eating a delicious, perfectly ripe banana is not beyond your control. If the bananas you brought home were unavoidably too green for your liking, you can use the same paper bag trick that works for apples; the principle of trapping ethylene gas will also speed-ripen a banana.

On the other hand, if your bananas have already hit the sweet spot before you are ready to eat them, refrigeration can be used to preserve their stage of ripeness and nutrient development. But be careful not to refrigerate them before they are ripe, as this will disrupt the process, and they may not ripen properly even if left out at room temperature afterward.

Banana allergies are very rare and most people can enjoy them safely. However there is a notable exception: those with latex allergies should be mindful and cautious, as bananas and plantains may cross-react.

It may also be a bit of a misconception that bananas, by virtue of their protective peel, are shielded from pesticides and organic bananas are therefore a waste of money. Unfortunately, pesticides sprayed on inorganic bananas will drip down into the soil to be taken up by the plant internally.


Banana Peel Tea

Don’t throw away that peel! Fascinatingly, everyone’s favourite happiness chemicals, the aforementioned neurotransmitters dopamine and serotonin, are amazingly abundant in banana peel- far beyond levels found in the fleshy fruit itself. At night or in the absence of light, serotonin is rapidly metabolized in the body to the sleepytime hormone melatonin.

This could be why, among those who know, banana peel tea in the evening is a classic home remedy to promote deep and restful sleep. The magnesium and potassium content of the peel can undoubtedly only contribute to the relaxing effects of banana peel tea.

Damien ZielinskiA cloud-based functional medicine practitioner with a focus on mental health and insomnia
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