Bananas are a good source of key nutrients that your mind needs to stay healthy! 

So, go ahead. Go bananas for bananas!

This is Episode 4 of the Foods for Mood Series: All About Bananas

About Bananas

Bananas are a staple food in many cultures around the world. They are so popular, in fact, that an estimated 20 million tons are grown each year⁽¹⁾.

Today, most bananas are grown in Latin America and the Caribbean, but the cultivation of bananas began in 600 A.D. in what is now known as India. Parts of Africa and Asia do still grow bananas and exports from there are growing⁽¹⁾.

Fun Facts About Bananas

• Musa is the botanical name for bananas
• Bananas grow from a rhizome, which is a bulb, not a seed 
• From the same plant family as the lily or orchid
• Only grow in hot, tropical climates
• Each tree can grow up to 20-40 feet in only nine months
• Each tree can bare up to 240 bananas
• Harvesting the bananas usually occurs around the one-year mark
• Workers cut off the “hands” (the clumps of bananas), then drop them down to be caught by another worker
• After harvest, the tree is cut down
• A new one will sprout from the rhizome

a Banana’s Journey: From Tree to Shelf

The Rainforest Alliance, an organization working to protect the world’s rainforests by preserving plant biodiversity, preventing deforestation, and protecting the human rights of those living and working there, tells us a lovely and detailed story of how bananas get from the tree to the grocery store shelf. Here is a summary.

Once off the tree, bananas are brought to the processing plant, where they are carefully cleaned, separated, and boxed to prevent bruising, rot, and spoilage. Now, they are ready for distribution.

The bananas are placed in trucks or barges designed to keep them refrigerated. This puts them to sleep and halts the ripening process.  

The bananas are placed in ripening rooms when they arrive at the distribution center to reinitiate the ripening process. After a  few days, they are removed and shipped off to grocery stores for consumer purchase.

Types

There are over 500 different species of bananas. Some are the type you buy, peel and eat; some require cooking, but all come in various sizes and are grown similarly.

In the US, the most popular type of banana is the cavendish, also known as the yellow banana. In fact, we are the world’s largest importer of this type of banana, with an average of 87 pounds per person purchased in 2021. That equals 81 (5-inch) bananas a year⁽²⁾!

Plantains are another popular banana here in the US. These large, green bananas grow to be an average of 10 inches long and are much starchier than yellow bananas. The firm flesh has a neutral flavor when green, but when yellow or brown, they taste much sweeter. Traditionally, plantains are cooked before consumption but can also be eaten raw when ripe.

Lady Fingers are another type of banana you might see at the grocery store. They are smaller and have thinner skin, but taste sweeter than regular yellow bananas. These bananas are often eaten as a dessert. 

Aversion to Bananas

I know it’s hard to believe, but many people report a “hatred” for bananas! For those of you who experience this, you’re wrong.

Seriously though, because I personally know so many people who hate bananas, I tried to see if there was a reason for their madness. Turns out, there are several possible reasons.

• Allergy
• GI upset
• Texture
• Taste

Only about 0.6% of the general population has a true allergy to bananas. Symptoms can range from oral allergy syndrome to anaphylaxis, and it usually shows up after experiencing a latex allergy ⁽³⁾. 

Information on the other reasons for such hatred and statistics showing the proportion of the population experiencing said disdain are scarce, and what is out there is anecdotal at best. This leaves ‘food preferences’ as the main reason why some people hate bananas.

If you don’t like the flavor or texture of bananas, that’s okay. I won’t force you to eat them.

I do, however, encourage you to eat more of the foods mentioned in the Foods for Mood series or alternatives such as other fruits, sweet potatoes. Cooking them is another option.

BanaNu-trition

Basic Nutrition

One medium-sized, ripe cavendish banana contains approximately:

• 110 calories
• 0 grams of fat
• 1 gram of protein
• 28 grams of carbohydrate
• 15 grams of naturally occurring sugar
• 3 grams of fiber
• 450 grams of potassium

Additional Nutrients in Bananas

Bananas are also a good source of⁽⁴⁾:

• Vitamin B6
• Magnesium
• Vitamin C
• Manganese

Minerals present in bananas include:

• Sodium
• Copper
• Iron
• Phosphorus
• Zinc
• Calcium

Bananas contain these polyphenols (aka antioxidants):

• Carotinoids (i.e., leutein, alpha- and beta-carotene)
• Flavonols (i.e., gallic acid)
• Sterols (i.e., catechins)
• Anthocyanins

Finally, bananas also have the following neurotransmitters:

• Dopamine
• Norepinephrine
• Serotonin 

Nutrient Concentrations Vary Slightly

Nutrient presence and concentration can vary by: 

• type/species of banana
• parts of the banana (peel vs pulp)
• growing conditions and harvest time
• ripeness
• preparation techniques 

Type/Species

The variety of bananas can dictate the percentage, or concentration, of each previously mentioned nutrient. For example, a lady finger has a higher (albeit naturally occurring) sugar content, whereas a plantain, at the same stage of ripeness, contains a higher percentage of complex carbohydrates and resistant starch (aka fiber). 

Parts of Banana

Banana peels contain higher nutrient concentrations than pulp or phloem bundles. Phloem bundles are the strings we often discard. They act as veins, transporting vital nutrients to the various parts of the banana. While we get a good dose from eating just the pulp, we miss out on so much when we discard the peel and strings.

Growing Conditions and Time of Harvest 

Soil conditions and other environmental factors (weather patterns, sun exposure, rainfall, etc.) affect how all plants grow, and banana trees are no exception. Because of these variables, nutrient concentrations vary slightly depending on where they are grown. Furthermore, when they are harvested also impacts the nutritional profile. This relates to ripening⁽⁵⁾.

Ripeness

Nutrient concentrations can change over time, too. For example, as cavendish (yellow bananas) ripen, the starches break down into simple sugars. Further, Boreges et al., who investigated how time and temperature affect the nutrient composition of bananas, report a reduction in neurotransmitter concentration as bananas ripen^(5,6).

Preparation Techniques 

Borges et al. also found that heating and cooking bananas can also influence nutrient concentrations. For example, dry heat reduces the water content, which increases the concentration of specific vitamins and minerals like Potassium while reducing the number of neurotransmitters present. Boiling appears to preserve nutrients somewhat and offers the most benefit if we consume water⁽⁶⁾. This is true for many of our foods, not just bananas.

Bananas and Your Mental Health

Bananas have many health benefits. They protect us against heart disease, aid in digestion, and promote healthy weight, as well as potentially improve our mental health.

But how? And which nutrients are involved?  

Nutrients like Vitamin B6, Magnesium, Antioxidants, Calcium, and Amino Acids, have been linked to mental health, and, you guessed it, bananas contain all of them! Let’s look at their relationship to mental health.

Vitamin B6 

Pyridoxine, also known as Vitamin B6, has many roles in the body, such as immune function and blood formation. It is also involved in brain development and acts as an enzymatic cofactor in the production and regulation of serotonin and dopamine.

Regarding moods, a recent literature review summarizes the various benefits B6 supplementation has on our mental health. From reducing stress to improving PMS symptoms, B6 has the potential to impact our mental health, particularly if we have insufficient levels at baseline⁽⁷⁾.

Magnesium 

Magnesium has several roles in body, including fluid regulation, cellular communication, bone health, and DNA synthesis. Regarding our mental health, magnesium is involved in neurotransmitter production and activity, inflammation, and sleep cycle regulation.

Rat models indicate magnesium supplementation can ameliorate symptoms of depression, but human studies are sparse and low quality. For now, there are no clinical recommendations, but consuming foods high in magnesium might boost our moods in addition giving us other health benefits⁽⁸⁾.

Antioxidants 

Antioxidants are chemical components in foods that might benefit our health by protecting us against free radicals. Free radicals are produced when environmental factors like pollution or poor diet damage our cells. Uncontrolled cellular damage results in chronic inflammation, damage to our DNA, or both, ultimately leading to disease⁽⁹⁾.

Antioxidants act on the brain in several ways. They neutralize free radicals, assist in reducing chronic inflammation, and play a role in enzymatic actions involved in brain communication pathways⁽⁹⁾. Diets rich in antioxidants promotes good mental and cognitive health.

Calcium

Calcium is often linked to bone health but is also essential in fluid regulation, muscle contractions, cardiovascular health, and hormone secretion. It also regulates neurotransmitter synthesis and release, both of which are implicated in mood regulation.

A recent 2022 study, using 1,233 college students in the US, found a negative association with higher calcium. This means that as intake increased, students had lower perceived stress, anxiety, rumination and higher higher positive mood scores and resilience scores⁽¹⁰⁾.

Neurotransmitters

It’s true! Bananas contain the neurotransmitters serotonin, dopamine, and norepinephrine, in addition to tyrosine and tryptophan, precursors to dopamine and serotonin, respectively. But does eating them impact our mental health?

Serotonin

When we consume nutrients, they enter our intestine, where the bulk of chemical digestion occurs. Usually, enzymes break nutrients into smaller bits so they can pass into the bloodstream but, in the case of neurotransmitters, things are a bit more complex. 

Serotonin from foods doesn’t cross the intestinal wall or blood-brain barrier. Enzymes in the intestine will break down some of the serotonin we eat into a size that can pass into the blood where it is sent to various sites throughout the body. These bits are then converted into all sort of things that aid in other bodily functions like sleep regulation, wound healing, and bone health.

The majority of dietary serotonin just stays in the intestine. In fact, 90% of our total serotonin actually resides in our gut! The bacteria living there actually produce loads of it! Here, serotonin serves multiple functions, including hunger and satiety cueing and speed of digestion.

The serotonin we associate with our mood is actually produced in the brain by our neurons using the amino acid tryptophan. Tryptophan is able to cross the blood-brain barrier, which the neurons then use to make serotonin. Lucky for us, tryptophan, which is generally associated with turkey, it is also found in plant foods like bananas.

While the serotonin we get from bananas doesn’t actually make it to the brain, it does, however, act in the gut to aid in digestion and absorption of other materials, like tryptophan, magnesium, calcium, and antioxidants, all of which affect the brain in one way or another.

Dopamine

In contrast, dietary dopamine and norepinephrine get absorbed and can increase circulating levels in our blood, but unfortunately, they are cleared relatively quickly. This means, like serotonin, the dopamine we take in through our food doesn’t make it to the brain either.

It is important to note that neurotransmitters are tightly managed by a system of checks and balances, and the presence and amount of neurotransmitters are directed by our genetics. This is why treatment options don’t include oral neurotransmitters. However, we have developed medications that can play with these checks and balances systems, such as selective serotonin reuptake inhibitors or SSRIs, that can and do influence the amounts of neurotransmitters and, consequently, our mood.

Do Bananas Improve Your Mood?

Given the information just discussed, theoretically, the nutrients found in bananas should have a positive impact on our mental health and mood, but let’s look at the research to see if this is the case.

In mice, regular consumption of banana and banana peel appears to reduce anxiety and depression behaviors as well as improve memory⁽¹¹⁾.

However, while research on rats looks promising, a large 2020 observational study of 24,673 Chinese adults (46% of whom were women, 16.1% with symptoms of depression) found a positive association with bananas (more symptoms of depression with more bananas being consumed) which contrasted with findings for men⁽¹²⁾.

Another human study done in 2018 found those who ate fresh fruits and vegetables had lower rates of depression and anxiety than those who ate processed versions of them⁽¹³⁾.

Further, a small 2020 study of 88 female college students found that those who ate bananas more frequently had reduced the severity of PMS symptoms during the premenstrual phase suggesting that higher intakes of B6, Magnesium, Calcium, and Iron, in addition to Vitamin D, appear to improve PMS symptoms and mood⁽¹⁴⁾.

To be honest, data specific to bananas is lacking, probably because people don’t only eat bananas. Most of the available information is observational, using incidence and food frequency questionnaires to make correlations. Several clinical trials that control for other lifestyle factors are required before a direct cause-effect relationship can be made that results in clinical recommendations (aka, a treatment prescribed by a medical doctor).

However, it’s a banana, and knowing that bananas give us the key nutrients associated with mood (directly or indirectly), suggests it might just be worth the try.

Besides, what’s the worst that can come of eating bananas!?

Negative Implications of Bananas

I’ve already mentioned how some people have a strong hatred for bananas, but this is a food preference thing. A true allergy to bananas is rare and often shows up after latex triggers the immune response. 

Toxicity might be another concern for some. Some of the nutrients in bananas can cause harm if consumed in large quantities (i.e., magnesium). However, it is difficult to get to those quantities from food alone. Typically we see toxicity with excessive supplementation. Always speak with your medical provider before adding a daily supplement.

Since bananas are high in carbohydrates, as both resistant starches and sugar, some might question whether or not they raise our blood sugar.  But I’ve got good news! A medium-sized, ripe banana has a low GI of 51 (Low GI foods: 1 to 55. Medium GI foods: 56 to 69. High GI foods: 70 and higher). Resistant starch is a form of soluble fiber, which our bodies can’t digest but tries to anyway. This slows digestion and the release of free sugars, thereby lowering the potential for them to raise blood sugar. Because of this, bananas actually help with blood sugar regulation.

However, fiber, in addition to slowing digestion, adds bulk. Generally, this is a good thing as it helps move things along and maximize nutrient absorption, but too much fiber can have adverse, too. Consuming too much fiber at one time and/or without sufficient amounts of water can cause bloating, gas, and constipation, which is not only uncomfortable but can lead to poor self-image and embarrassment.

My Recommendations

Bananas are a low-risk food associated with many potential health benefits, including our mental health. Given this low-risk ratio, I say…

Try these products!

Disclosure: I may receive monetary compensation for recommending certain products here or within the Dietitian’s Cauldron Website. Help a small business out and order through my affiliate links.

Try plantains!

Picking the perfect plantain

Unlike bananas, plantains are at their peak when the peel is just about 50% black.

You can purchase them at any stage but know that you may have to wait for them to ripen to perfection. Plan ahead, time your purchase, or force them to ripen by placing them in a brown paper bag with other fruits, such as apples or avocados. The ethylene gas released from these fruits will stimulate and speed up the ripening process. 

This works in the reverse direction as well. So, if you’re looking to ripen a hard avocado, place in a brown bag with ripe bananas for a day or so. 

Cooking Plantains

My favorite way to eat plantains is fried (sauteed, really).

1. Peel the plantains.
2. Slice them into medallions.
3. Flash fry in 1/4 inch of hot oil for 3-5 minutes.
4. Remove from oil and place on a paper towel to cool.
5. Once cooled, smash the medallions so they are thinner, and the flesh squeezes out the sides.
6. Fry again until golden brown.
7. Strain from oil and season to taste.
8. Allow it to cool for 10 minutes before eating!

Use Your Banana Peels

The research and science communities are working hard to develop alternative ways to utilize banana peels on a large scale. So far, they can extract the pectin to use in other products; use it as a supplementary feed for livestock, or make it into flour that can be used in a number of food products.

At home, you can:

• Fertilize your house plants! For indoor plants, chop up the peels and incorporate directly into the soil, or soak them in water for two days, strain them, and use the infused water to water your plants.
• Use as a Skin Treatment. Pureed, scraped, or as is, applying the peels to our skin might add moisture, increase antioxidant and vitamin presence and activity, and reduce inflammation. However, none of these are clinically proven, but with few risks, it might be worth a try.
• Eat Them! Finally, and interestingly, we can find ways to consume the peels. Use as a tea by drying and/or boiling them. Or, try them seasoned and baked into a chip! Yum!

BananAppetit, Witches!