How Bananas Contribute To Stronger Bone Density

Overview 

Bananas may not be what first comes to mind when thinking about building strong bones, however, this superfood comes with many benefits including increasing bone density. They are excellent sources of minerals such as potassium, phosphorus, and magnesium. These minerals play a vital role in building strong bones, thereby reducing one’s risk of fractures.

Several studies have shown that potassium intake can increase bone density; this is thought to be due to the alkalizing effect of bananas, which will be explained later.^1,2,3,4 Bones are made up of a significant amount of phosphate, which contributes to building healthy bones through bone mineralization. Magnesium is another important constituent of bones. Some studies have shown a link between magnesium intake and increased bone mineral densities.^6,7

Bone density: definition & importance

Bone strength is determined by bone density and bone quality.⁸ Bone density is a measure of the amount of minerals (calcium and phosphorus) in a certain volume of bone. The strength of bones depends 60% on bone density, with a higher bone density contributing to stronger bones. 

Genetics mostly determine one’s bone density (60 - 80%). However, lifestyle factors such as exercise and nutrition, can also affect bone density. Bone density is greatest around 25 years old, and begins to decline after age 35. 

Bones are important as they allow us to stand, walk, sit, dance, and carry out all our movements. They are not completely solid but rather have spongy interiors which keep them light and shock resistant. However, when there is reduced bone density (reduced mineral content), your bones are more likely to fracture. Osteoporosis and osteopenia, common globally, are conditions in which there is reduced bone density.

In the UK, around 3.8 million people had osteoporosis in 2019, with 80% being women. The lifetime probability of having a hip fracture is about 14% in women compared to 5% in men above 50. In addition, the number of fragility fractures is expected to rise. Fractures can render patients bedridden, robbing them of their independence and quality of life, as well as being costly to the NHS. Considering these statistics, it is crucial to build a healthy bone density in childhood and reduce bone loss that occurs with ageing.

Some actions can be taken to build high bone density in youth, maintain this, and reduce the loss due to ageing. These include keeping active and having a nutritious diet, especially with recommended amounts of minerals such as calcium and phosphorus, important in building strong bones. Taking adequate amount of vitamin D is important as it aids the absorption of calcium in the gut. Other factors include stopping smoking and reducing alcohol intake.

Bone-building nutrients in bananas 

Bananas are abundant in nutrients and vitamins; the ones of importance to bone density, and available in amounts per 100g, are listed below. 

Potassium’s role in bone density 

While it is widely known that calcium and vitamin D are critical for building strong bones, research has shown that other nutrients are equally important for bone density. 

It has been shown that potassium is important for bone health. Consuming fruits and vegetables containing potassium may lead to less bone resorption (breakdown). Some studies have shown that increased intake of potassium reduces urinary calcium excretion, lowers markers of bone resorption, and has a link to improved bone density. 

Bananas contain a significant amount of potassium, 1 portion containing 358 mg, which is 10% of the daily recommended potassium intake. The link to increased bone density is mostly thought to be due to potassium's effect on acid-base balance. As the acidity increases, there is more bone breakdown to release calcium to restore the pH of the body. Bananas like other fruits, have an alkalizing effect and can restore the pH, leading to less bone breakdown, reducing the need to release calcium and restore the body’s pH. 

Magnesium & bone density 

A significant portion (60%) of the body’s magnesium is located in the bones. Several studies have shown a link between magnesium intake and greater bone densities.^6,7 Magnesium may improve bone quality and density by affecting the growth of hydroxyapatite crystals in bone.

Hydroxyapatite makes up the inner part of your bones, called the matrix. Hydroxyapatite consists of calcium phosphate. It also contains magnesium which is found in combination with calcium and phosphorus. One portion of the banana provides 27mg of magnesium. This represents 9% (for males) and 10% (for females) the recommended daily requirement of magnesium intake.

A meta-analysis, which is research that analyses the results of several studies, conducted in 2022, concluded that a high intake of magnesium was associated with a higher hip and femoral neck (thigh) bone mineral density.⁶ Magnesium assists in the formation of the bone matrix (inner part of bones) and it stimulates osteoblasts, which are cells in the bone that make new bone. A lack of magnesium can lead to abnormal hydroxyapatite crystals and an increase in inflammation and stimulation of osteoclasts, cells that break down bone.⁶

In many Western countries, magnesium consumption in adults is lower than the daily recommended requirement. The elderly, in particular, are at risk of magnesium deficiency which is attributable to decreased absorption and increased excretion.⁶

Another research showed that a higher intake of magnesium and potassium was associated with a higher total bone mass.⁷ They also showed that the bone mineral density of the femoral neck was higher in women who consumed more fruits in childhood. Another \showed concurrent results, with higher intakes of magnesium, potassium, and fruits and vegetables, associated with the maintenance of bone mineral density.⁴

Phosphorus & bone density

More than half of the minerals in the bones consist of phosphates and 85% of the body’s phosphorus is located in the bones. The matrix of bones (inner part of bones) is made up of hydroxyapatite, which consists of calcium phosphate. 

Most people consume diets containing high amounts of phosphorus, as phosphorus is found in many foods. However, about 10-15% of older women have intakes less than 70%.⁵ A deficiency of phosphorus limits the mineralization at new bone-forming sites, in all age groups, reduces the function of osteoblasts, bone-forming cells, and increases the action of osteoclasts, which break bone down.⁵

Phosphates play a role in building healthy bones through bone mineralization. Unfortunately, some calcium supplements, in the form of calcium citrates or carbonates, can decrease the absorption of phosphate, from the gut.⁵ Ways to overcome this include taking a calcium phosphate supplement or increasing your dietary phosphate consumption e.g. taking bananas or drinking milk. Bananas contain 22 mg of phosphorus per 100 mg. Whilst this is only 4% of the daily recommended intake of phosphate, it remains a healthy source of phosphate. 

Other benefits of bananas 

Bananas are nutritious fruits, with many benefits. Listed below are some other benefits of bananas: 

• High in fibre - supporting the gut 
• Potassium - helps regulate heart function 
• Relieves heartburn by neutralizing stomach acid
• Provides instant & sustained energy 
• Leads to increased serotonin

You can increase your banana intake by adding banana to your breakfast cereal, swapping unhealthy snacks for a banana, and have a smoothie containing bananas and milk. If you are diabetic, it is best to limit your intake of bananas. If you have a medical condition that requires limiting potassium intake such as renal disease, it is also advisable to consume bananas in moderation.

When taking some medications e.g. those for high blood pressure, you may experience high potassium levels. In this case, you should also limit your banana intake as high potassium levels are dangerous, especially affecting c heart function. Consult a doctor in these scenarios. 

Summary 

A high bone density contributes significantly to bone strength and reduces one’s risk of fractures. Consuming a nutritious diet and keeping active is important for maximizing bone density in childhood and reducing the loss that occurs with ageing. The consequences of low bone density are numerous, including an increased risk of fractures and a reduced quality of life.

Bananas contribute to building strong bone density as they contain minerals such as potassium, magnesium, and phosphate required for healthy bone formation. Several research studies have linked higher intakes of these minerals to a higher bone mineral density. One study revealed that calcium phosphate supplements are superior to calcium citrate/carbonate supplements when it comes to maintaining high bone density.

Other nutrients that may have a beneficial effect on bone health include vitamin K, vitamin C, copper, manganese, zinc, and iron.