Health experts have long been singing the praises of the humble banana, and it’s no surprise. They’re easily available, count as one of your five a day, and at only about 90 calories per fruit are packed with the essential mineral potassium, which scientists think could be crucial in the fight against high blood pressure (a third of adults in England they are thought to suffer from the condition.)
But is the popular fruit really such a health savior? Telegraph readers are divided, and eAndy Murray – often seen munching on the track – called them “a pathetic fruit” that “isn’t even juicy”. He ate them, he said, because of “what they have in them.”
Interestingly, banana bonuses change depending on how ripe they are. “It’s fascinating to see how the different stages of the fruit develop and know that this can make a difference to the health benefits achieved – or not,” says Penny Weston, the nutritionist behind wellness platform MADE. “Barely ripe bananas contain a lot of fiber and little sugar. And while they may taste more bitter, plenty of fiber is good for feeding gut bacteria and aiding the process through the intestines. Keeping your intestines healthy is good for the rest of your body.”
It is also worth remembering that “although a very ripe banana is easiest for the intestines to digest, this is because it contains the least starch, and an overripe banana has the highest sugar and lowest fiber and vitamin content “.
So what are the pros and cons of making the fruit one of your five a day?
The pros
They are packed with potassium for your heart health and blood pressure
“Bananas are a good source of potassium, with one banana containing 451 mg (about 10 percent of your daily needs),” says Weston.
They are also low in sodium, which, along with their high potassium content, helps control high blood pressure.
They are a surprisingly good source of vitamin C
We tend to reach for citrus fruits for vitamin C, but a medium banana provides a respectable 10 percent of your daily vitamin C needs.
“Vitamin C is very important to the body for several reasons,” says Weston. “It helps with immunity and maintenance of normal skin, bones and cartilage. It also helps protect our cells and keep them healthy, but also aids in wound healing and supports our body in the absorption of iron.”
Bananas can promote digestion
We all know the importance of fiber, and one medium banana provides about 10 to 12 percent of your daily needs. “Traditionally, bananas have been found to relieve constipation, stomach ulcers and heartburn,” says Weston.
They give you energy
Bananas contain three natural sugars – sucrose, fructose and glucose – giving you a fat- and cholesterol-free energy source. The mix of carbohydrates and potassium is helpful for exercise performance and muscle growth.
“This makes them ideal for athletes and children. They are delicious for breakfast as a snack or before and after exercise,” says Weston. “They are low in calories yet filling because of the aforementioned fiber content. They are also rich in magnesium and a variety of antioxidants, such as flavonoids, which may reduce the risk of heart disease.”
They can reduce your risk of cancer
A study led by experts from the Universities of Newcastle and Leeds and published in the journal Cancer Prevention Research suggested that unripened bananas could have important implications in reducing cancer in the upper intestine.
“There is some research that suggests the starch in an unripe banana can reduce the risk of some cancers by 60 percent,” says Weston.
The cons
You can have too much potassium
“An excess of potassium can occur if you eat too many bananas,” says Weston. “Having too much potassium in the body is called hyperkalemia.”
As one Telegraph reader – with mild kidney disease – noted, his adviser told him to avoid bananas because “even small amounts of potassium” can worsen kidney function. So if you’ve been diagnosed with reduced kidney function, it may be worth keeping an eye on your potassium intake.
Dr. Tom Oates, an NHS consultant nephrologist, says: “We tell patients with advanced kidney disease and dialysis to be very careful with potassium.” He says bananas, avocado and dried fruit are all high in potassium, so “safer are apples, pears and small citrus fruits such as satsumas”.
They can cause flatulence and bloating
“Some people may experience bloating or gas after eating a banana because of the sorbitol, a naturally occurring sugar alcohol that can have a laxative effect,” explains Weston. “People who are not used to a high-fiber diet may also experience some discomfort after eating a banana, such as cramps and bloating.”
As one Telegraph reader noted: “I eat a few bananas every day, I knew they were not good for greenhouse gas emissions.” The less ripe the banana, the more difficult it is to digest.
They can increase your blood sugar levels
“This is because the carbohydrates are broken down into glucose,” says Weston. “I would recommend combining your bananas with full-fat yoghurt to avoid this, or eating one after a balanced meal.
“If you have type 2 diabetes, you can eat bananas in moderation,” she adds. “There is little evidence that bananas can cause type 2 diabetes.”
Too much makes you fat
Yes, we’re all constantly encouraged to consume more fruit, but like any food, overdo it and you’ll gain weight. As another Telegraph reader said: “Bananas are basically Mars bars with yellow skin. Obesity is the leading cause of essential hypertension.”
Weston recommends limiting intake to “no more than two bananas per day,” adding:
“Bananas are carbohydrates and contain sugar, so eating a lot of bananas and not combining them with physical activity can lead to weight gain – but this is just like most foods!”
Avoid them before bedtime
Although they are clearly healthier than eating a cookie with your evening cocoa, they are apparently not the best snack to consume before bed.
“Some experts suggest you should avoid a banana before bed as it can cause restless sleep due to the high levels of melatonin (a sleep hormone) they contain, which can cause an imbalance,” says Weston. However, she adds that if you personally don’t find it affecting your sleep, she would say it’s not a bad bedtime snack because “a banana can be digested quickly.”
Finally…
Weston says banana consumption is truly an individual matter. “If you like them, enjoy them,” she says, although she wouldn’t recommend eating more than two a day.
“Just like with any other food, you have to listen to your body and how it reacts. If you personally find that eating them doesn’t seem to agree with you, or with your digestive system, look at other ways to get the nutritional benefits they clearly do.
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