Cranberry juice has been used medicinally for centuries. Our new research indicates it should be a normal aspect of urinary tract infection (UTI) management today.

While some benefits of cranberry compounds for the prevention of UTIs have been suspected for some time, it hasn’t been clear whether the benefits from cranberry juice were simply from drinking more fluid, or something in the fruit itself.

For our study, published this week, we combined and collectively assessed 3,091 participants across more than 20 clinical trials.

Our analysis indicates that increasing liquids reduces the rate of UTIs compared with no treatment, but cranberry in liquid form is even better at reducing UTIs and antibiotic use.

Are UTIs really that bad?

Urinary tract infections affect more than 50% of women and 20% of men in their lifetime.

Most commonly, UTIs are caused from the bug called Escherichia coli (E.coli). This bug lives harmlessly in our intestines, but can cause infection in the urinary tract. This is why, particularly for women, it is recommended people wipe from front to back after using the toilet.

An untreated UTI can move up to the kidneys and cause even more serious illness.

Even when not managing infection, many people are anxious about contracting a UTI. Sexually active women, pregnant women and older women may all be at increased risk.

Why cranberries?

To cause a UTI, the bacteria need to attach to the wall of the urinary bladder. Increasing fluids helps to flush out bacteria before it attaches (or makes its way up into the bladder).

Some beneficial compounds in cranberry, such as proanthocyanidins (also called condensed tannins), prevent the bacteria from attaching to the wall itself.

While there are treatments, over 90% of the bugs that cause UTIs exhibit some form of microbial resistance. This suggests that they are rapidly changing and some cases of UTI might be left untreatable.

What we found

Our analysis showed a 54% lower rate of UTIs from cranberry juice consumption compared to no treatment. This means that significantly fewer participants who regularly consumed cranberry juice (most commonly around 200 millilitres each day) reported having a UTI during the periods assessed in the studies we analysed.

Cranberry juice was also linked to a 49% lower rate of antibiotic use than placebo liquid and a 59% lower rate than no treatment, based on analysis of indirect and direct effects across six studies. The use of cranberry compounds, whether in drinks or tablet form, also reduced the prevalence of symptoms associated with UTIs.

While some studies we included presented conflicts of interest (such as receiving funding from cranberry companies), we took this “high risk of bias” into account when analysing the data.

So, when can cranberry juice help?

We found three main benefits of cranberry juice for UTIs.

1. Reduced rates of infections

Increasing fluids (for example, drinking more water) reduced the prevalence of UTIs, and taking cranberry compounds (such as tablets) was also beneficial. But the most benefits were identified from increasing fluids and taking cranberry compounds at the same time, such as with cranberry juice.

2. Reduced use of antibiotics

The data shows cranberry juice lowers the need to use antibiotics by 59%. This was identified as fewer participants in randomised cranberry juice groups required antibiotics.

Increasing fluid intake also helped reduce antibiotic use (by 25%). But this was not as useful as increasing fluids at the same time as using cranberry compounds.

Cranberry compounds alone (such as tablets without associated increases in fluid intake) did not affect antibiotic use.

3. Reducing symptoms

Taking cranberry compounds (in any form, liquid or tablet) reduced the symptoms of UTIs, as measured in the overall data, by more than five times.

Take home advice

While cranberry juice cannot treat a UTI, it can certainly be part of UTI management.

If you suspect that you have a UTI, see your GP as soon as possible.

Christian Moro, Associate Professor of Science & Medicine, Bond University and Charlotte Phelps, Senior Teaching Fellow, Medical Program, Bond University

This article is republished from The Conversation under a Creative Commons license. Read the original article.

This is the next article in our ‘Light and health’ series, where we look at how light affects our physical and mental health in sometimes surprising ways. Read other articles in the series.

Exposure to light is crucial for our physical and mental health, as this and future articles in the series will show.

But the timing of that light exposure is also crucial. This tells our body to wake up in the morning, when to poo and the time of day to best focus or be alert. When we’re exposed to light also controls our body temperature, blood pressure and even chemical reactions in our body.

But how does our body know when it’s time to do all this? And what’s light got to do with it?

What is the body clock, actually?

One of the key roles of light is to re-set our body clock, also known as the circadian clock. This works like an internal oscillator, similar to an actual clock, ticking away as you read this article.

But rather than ticking you can hear, the body clock is a network of genes and proteins that regulate each other. This network sends signals to organs via hormones and the nervous system. These complex loops of interactions and communications have a rhythm of about 24 hours.

In fact, we don’t have one clock, we have trillions of body clocks throughout the body. The central clock is in the hypothalamus region of the brain, and each cell in every organ has its own. These clocks work in concert to help us adapt to the daily cycle of light and dark, aligning our body’s functions with the time of day.

However, our body clock is not precise and works to a rhythm of about 24 hours (24 hours 30 minutes on average). So every morning, the central clock needs to be reset, signalling the start of a new day. This is why light is so important.

The central clock is directly connected to light-sensing cells in our retinas (the back of the eye). This daily re-setting of the body clock with morning light is essential for ensuring our body works well, in sync with our environment.

In parallel, when we eat food also plays a role in re-setting the body clock, but this time the clock in organs other than the brain, such as the liver, kidneys or the gut.

So it’s easy to see how our daily routines are closely linked with our body clocks. And in turn, our body clocks shape how our body works at set times of the day.

What time of day?

Let’s take a closer look at sleep

The naturally occurring brain hormone melatonin is linked to our central clock and makes us feel sleepy at certain times of day. When it’s light, our body stops making melatonin (its production is inhibited) and we are alert. Closer to bedtime, the hormone is made, then secreted, making us feel drowsy.

Our sleep is also partly controlled by our genes, which are part of our central clock. These genes influence our chronotype – whether we are a “lark” (early riser), “night owl” (late sleeper) or a “dove” (somewhere in between).

But exposure to light at night when we are supposed to be sleeping can have harmful effects. Even dim light from light pollution can impair our heart rate and how we metabolise sugar (glucose), may lead to psychiatric disorders such as depression, anxiety and bipolar disorder, and increases the overall risk of premature death.

The main reason for these harmful effects is that light “at the wrong time” disturbs the body clock, and these effects are more pronounced for “night owls”.

This “misaligned” exposure to light is also connected to the detrimental health effects we often see in people who work night shifts, such as an increased risk of cancer, diabetes and heart disease.

How about the gut?

Digestion also follows a circadian rhythm. Muscles in the colon that help move waste are more active during the day and slow down at night.

The most significant increase in colon movement starts at 6.30am. This is one of the reasons why most people feel the urge to poo in the early morning rather than at night.

The gut’s day-night rhythm is a direct result of the action of the gut’s own clock and the central clock (which synchronises the gut with the rest of the body). It’s also influenced by when we eat.

How about focusing?

Our body clock also helps control our attention and alertness levels by changing how our brain functions at certain times of day. Attention and alertness levels improve in the afternoon and evening but dip during the night and early morning.

Those fluctuations impact performance and can lead to decreased productivity and an increased risk of errors and accidents during the less-alert hours.

So it’s important to perform certain tasks that require our attention at certain times of day. That includes driving. In fact, disruption of the circadian clock at the start of daylight savings – when our body hasn’t had a chance to adapt to the clocks changing – increases the risk of a car accident, particularly in the morning.

What else does our body clock control?

Our body clock influences many other aspects of our biology, including:

• physical performance by controlling the activity of our muscles
• blood pressure by controlling the system of hormones involved in regulating our blood volume and blood vessels
• body temperature by controlling our metabolism and our level of physical activity
• how our body handles drugs and toxins by controlling enzymes involved in how the liver and kidneys eliminate these substances from the body.

Morning light is important

But what does this all mean for us? Exposure to light, especially in the morning, is crucial for synchronising our circadian clock and bodily functions.

As well as setting us up for a good night’s sleep, increased morning light exposure benefits our mental health and reduces the risk of obesity. So boosting our exposure to morning light – for example, by going for a walk, or having breakfast outside – can directly benefit our mental and metabolic health.

However, there are other aspects about which we have less control, including the genes that control our body clock.

Frederic Gachon, Associate Professor, Physiology of Circadian Rhythms, Institute for Molecular Bioscience, The University of Queensland and Benjamin Weger, NHMRC Emerging Leadership Fellow Institute for Molecular Bioscience, The University of Queensland

This article is republished from The Conversation under a Creative Commons license. Read the original article.