Health check: will eating nuts make you gain weight?



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Nuts contain “good” fats.
From shutterstock.com

Elizabeth Neale, University of Wollongong; Sze-Yen Tan, Deakin University, and Yasmine Probst, University of Wollongong

The Australian Dietary Guidelines recommend we eat 30g of nuts – a small handful – each day. But many of us know nuts are high in calories and fat.

So should we be eating nuts or will they make us gain weight?

In short, the answer is yes, we should eat them, and no, they won’t make us gain weight if eaten in moderate amounts. The fats in nuts are mostly the “good” fats. And aside from that, our bodies don’t actually absorb all the fat found in nuts. But we do absorb the nutrients they provide.




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Dietary fat: friend or foe?

Nuts do contain fat, and the amount of fat varies between nut types. For example, a 30g serving of raw cashews or pistachios contains around 15g of fat, whereas the same amount of raw macadamias contains around 22g of fat.

There are different kinds of fats in our diet and some are better for us than others. Nuts contain mainly monounsaturated and polyunsaturated fats. These types of fats are known as “good fats”. They can help lower cholesterol when we eat them in place of saturated fats.

The type of fats present varies between nuts. For example, walnuts are rich in polyunsaturated fats, whereas other types of nuts such as hazelnuts and macadamias have more monounsaturated fat.

What the evidence says

Even if the type of fat in nuts is good for us, they are still high in fat and calories. But this doesn’t mean we should be avoiding them to manage our weight.

Studies that looked at people’s eating habits and body weight over a long period have found people who regularly eat nuts tend to gain less weight over time than people who don’t.

Nuts are a healthier option for a snack than many processed alternatives.
From shutterstock.com

We see a similar pattern in clinical studies that asked people to include nuts in their diets and then looked at the effects on body weight.

A review of more than 30 studies examined the effects of eating nuts on body weight. It did not find people who ate nuts had increased their body weight, body mass index (BMI), or waist circumference, compared to a control group of people who did not eat nuts.

In fact, one study found that when people ate a pattern of food aimed at weight loss, the group of people who ate nuts lost more body fat than those who didn’t eat nuts.




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Let’s nut this out

There are several possible explanations for why eating nuts doesn’t seem to lead to weight gain.

  1. We don’t absorb all of the fat in nuts: The fat in nuts is stored in the nut’s cell walls, which don’t easily break down during digestion. As a result, when we eat nuts, we don’t absorb all of the fat. Some of the fat instead is passed out in our faeces. The amount of calories we absorb from eating nuts might be between 5% and 30% less that what we had previously thought.

  2. Nuts increase the amount of calories we burn: Not only do we not absorb all the calories in nuts, but eating nuts may also increase the amount of energy and fat we burn. It’s thought this may partially be explained by the protein and unsaturated fats in nuts, although we don’t yet know exactly how this occurs. Increases in the number of calories burnt can help us maintain or lose weight.

  3. Nuts help us feel full for longer: As well as fat, nuts are rich in protein and fibre. So, nuts help to keep us feeling full after we eat them, meaning we’re likely to eat less at later meals. Recent studies have also suggested providing people with nuts helps improve the overall quality of the types of foods they eat. This may be because nuts replace “junk foods” as snacks.

  4. People who eat nuts have healthier lifestyles in general: We can’t rule out the idea that eating nuts is just a sign of a healthier lifestyle. However, randomised controlled trials, which can control for lifestyle factors like eating habits, still find no negative effect on body weight when people eat nuts. This means the favourable effects of nuts are not just the result of nut eaters having healthier lifestyles – the nuts themselves play a role.




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Overall, the evidence suggests nuts are a healthy snack that can provide us with many of the nutrients our bodies need. We can confidently include the recommended 30g of nuts a day in a healthy diet, without worrying about the effect they will have on our waistlines.The Conversation

Elizabeth Neale, Career Development Fellow (Lecturer), University of Wollongong; Sze-Yen Tan, Senior Lecturer in Nutrition Science, Institute for Physical Activity and Nutrition (IPAN), School of Exercise and Nutrition Sciences, Deakin University, and Yasmine Probst, Senior lecturer, School of Medicine, University of Wollongong

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

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Here’s what you need to know about melioidosis, the deadly infection that can spread after floods



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People typically become sick between one and 21 days after being infected.
Goran Jakus/Shutterstock

Sanjaya Senanayake, Australian National University

The devastating Townsville floods have receded but the clean up is being complicated by the appearance of a serious bacterial infection known as melioidosis. One person has died from melioidosis and nine others have been diagnosed with the disease over the past week.

The bacteria that causes the disease, Burkholderia pseudomallei, is a hardy bug that lives around 30cm deep in clay soil. Events that disturb the soil, such as heavy rains and floods, bring B. pseudomallei to the surface, where it can enter the body through through a small break in the skin (that a person may not even be aware of), or by other means.

Melioidosis may cause an ulcer at that site, and from there, spread to multiple sites in the body via the bloodstream. Alternatively, the bacterium can be inhaled, after which it travels to the lungs, and again may spread via the bloodstream. Less commonly, it’s ingested.




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(At least) five reasons you should wear gardening gloves


Melioidosis was first identified in the early 20th century among drug users in Myanmar. These days, cases tend to concentrate in Southeast Asia and the top end of northern Australia.

What are the symptoms?

Melioidosis can cause a variety of symptoms, but often presents as a non-specific flu-like illness with fever, headache, cough, shortness of breath, disorientation, and pain in the stomach, muscles or joints.

People with underlying conditions that impair their immune system – such as diabetes, chronic kidney or lung disease, and alcohol use disorder – are more likely to become sick from the infection.

The majority of healthy people infected by melioidosis won’t have any symptoms, but just because you’re healthy, doesn’t mean you’re immune: around 20% of people who become acutely ill with melioidosis have no identifiable risk factors.

People typically become sick between one and 21 days after being infected. But in a minority of cases, this incubation period can be much longer, with one case occurring after 62 years.

How does it make you sick?

While most people who are sick with melioidosis will have an acute illness, lasting a short time, a small number can have a grumbling infection persisting for months.

One of the most common manifestations of melioidosis is infection of the lungs (pneumonia), which can occur either via infection through the skin, or inhalation of B. pseudomallei.

The challenges in treating this organism, though, arise from its ability to form large pockets of pus (abscesses) in virtually any part of the body. Abscesses can be harder to treat with antibiotics alone and may also require drainage by a surgeon or radiologist.

How is it treated?

Thankfully, a number of antibiotics can kill B. pseudomallei. Those recovering from the infection will need to take antibiotics for at least three months to cure it completely.

If you think you might have melioidosis, seek medical attention immediately. A prompt clinical assessment will determine the level of care you need, and allow antibiotic therapy to be started in a timely manner.

Your blood and any obviously infected body fluids (sputum, pus, and so on) will also be tested for B. pseudomallei or other pathogens that may be causing the illness.

While cleaning up after these floods, make sure you wear gloves and boots to minimise the risk of infection through breaks in the skin. This especially applies to people at highest risk of developing melioidosis, namely those with diabetes, alcohol use disorder, chronic kidney disease, and lung disease.




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The Conversation


Sanjaya Senanayake, Associate Professor of Medicine, Infectious Diseases Physician, Australian National University

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

Health Check: do we really need to take 10,000 steps a day?



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Walking has a variety of health benefits.
From shutterstock.com

Corneel Vandelanotte, CQUniversity Australia; Kerry Mummery, University of Alberta; Mitch Duncan, University of Newcastle, and Wendy Brown, The University of Queensland

Regular walking produces many health benefits, including reducing our risk of heart disease, type 2 diabetes and depression.

Best of all, it’s free, we can do it anywhere and, for most of us, it’s relatively easy to fit into our daily routines.

We often hear 10,000 as the golden number of steps to strive for in a day. But do we really need to take 10,000 steps a day?

Not necessarily. This figure was originally popularised as part of a marketing campaign, and has been subject to some criticism. But if it gets you walking more, it might be a good goal to work towards.




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Where did 10,000 come from?

The 10,000 steps concept was initially formulated in Japan in the lead-up to the 1964 Tokyo Olympics. There was no real evidence to support this target. Rather, it was a marketing strategy to sell step counters.

There was very little interest in the idea until the turn of the century, when the concept was revisited by Australian health promotion researchers in 2001 to encourage people to be more active.

Based on accumulated evidence, many physical activity guidelines around the world – including the Australian guidelines – recommend a minimum of 150 minutes of moderate intensity physical activity a week. This equates to 30 minutes on most days. A half hour of activity corresponds to about 3,000 to 4,000 dedicated steps at a moderate pace.

In Australia, the average adult accumulates about 7,400 steps a day. So an additional 3,000 to 4,000 steps through dedicated walking will get you to the 10,000 steps target.




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One size doesn’t fit all

Of course, some people accumulate a lot fewer steps per day – for example, older people, those with a chronic disease, and office workers. And others do a lot more: children, runners, and some blue-collar workers. So the 10,000 goal is not suitable for everyone.

Setting a lower individual step goal is fine as long as you try to add about 3,000 to 4,000 steps to your day. This means you will have done your 30 minutes of activity.

People measure their daily steps using a variety of activity trackers.
From shutterstock.com

Studies that examine how the number of daily steps relates to health benefits have mainly been cross-sectional. This means they present a snapshot, and don’t look at how changes in steps affect people’s health over time. Therefore, what we call “reverse causality” may occur. So rather than more steps leading to increased health benefits, being healthier may in fact lead to taking more steps.

Nonetheless, most studies do find taking more steps is associated with better health outcomes.

Several studies have shown improved health outcomes even in participants who take less than 10,000 steps. An Australian study, for example, found people who took more than 5,000 steps a day had a much lower risk of heart disease and stroke than those who took less than 5,000 steps.

Another study found that women who did 5,000 steps a day had a significantly lower risk of being overweight or having high blood pressure than those who did not.

The more the better

Many studies do, however, show a greater number of steps leads to increased health benefits.

An American study from 2010 found a 10% reduction in the occurrence of metabolic syndrome (a collection of conditions that increase your risk of diabetes, heart disease and stroke) for each 1,000-step increase per day.

An Australian study from 2015 demonstrated that each 1,000-step increase per day reduced the risk of dying prematurely of any cause by 6%, with those taking 10,000 or more steps having a 46% lower risk of early death.




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Another Australian study from 2017 showed people with increasingly higher step counts spent less time in hospital.

So the bottom line is the more steps, the better.

Step it up

It’s important to recognise that no public health guideline is entirely appropriate for every person; public health messages are aimed at the population at large.

That being said, we shouldn’t underestimate the power of a simple public health message: 10,000 steps is an easily remembered goal and you can readily measure and assess your progress. You can use an activity tracker, or follow your progress through a program such as 10,000 Steps Australia.

Increasing your activity levels, through increasing your daily step count, is worthwhile; even if 10,000 steps is not the right goal for you. The most important thing is being as active as you can. Striving for 10,000 steps is just one way of doing this.The Conversation

Corneel Vandelanotte, Professorial Research Fellow: Physical Activity and Health, CQUniversity Australia; Kerry Mummery, Dean, Faculty of Kinesiology, Sport and Recreation, University of Alberta; Mitch Duncan, , University of Newcastle, and Wendy Brown, Professor of Human Movement Studies, The University of Queensland

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

Health Check: why do we itch?



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Feeling itch is a warning from your skin.
from http://www.shutterstock.com

Yuan Lei, Chinese Academy of Sciences and Yan-Gang Sun, Chinese Academy of Sciences

We’ve all experienced the unpleasant sensation of being itchy. For many years, scientists suspected that pain and itch were the same thing, only differentiated by their intensity: itch was just light pain, and pain was strong itch.

But we now know these two sensations are perceived very differently. Recent research found itch is sensed through its own dedicated nerves, independent of the pain pathway.




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How do we feel itch?

Acute itch (medically known as pruritus) is usually caused by something harmful, such as biting insects or allergic chemicals on the skin, as a warning signal to protect us from potential threat.

After detecting this stimuli, cells in the skin (called keratinocytes) communicate with immune cells between the layers of the skin. In order to clear away any potential invading pathogens, the immune cells release chemicals such as histamine, serotonin, and proteases. These then activate sensory fibers which initiate the transmission of a warning message.

Several different molecules and cells in the nerves and brain of animal models have been shown to mediate the transmission of the itch signal from skin to brain through the spinal cord.

Traditionally, itch is separated into two pathways, depending on whether they respond to anti-histamine medicine or not (this is the medicine you take to prevent hay fever). Histamine activates its own sensors, while the other type (non-histaminergic pruritogens) use other receptors to fire the itch-detecting cells.




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The interaction between itch and pain/touch

Pain and itch are clearly distinct sensations that provoke different responses. When your hand senses a fire, you will definitely withdraw your hand immediately; by contrast, when you get bitten by a mosquito, you’ll scratch to get rid of the irritation without hesitation. This tells us something about the threat level involved with each sensation.

Although itch has its own messengers, the sensation does also share some sensors with the sensations of pain and touch. This is why pain can counterbalance the sensation of itch – like when you apply frozen peas to an itchy skin condition such as eczema. And why a light touch can provoke itch (tickling).

Why scratching both quenches and enhances itch

Usually when we feel an itch, we scratch it. But sometimes the more we scratch, the itchier we feel. This vicious itch-scratch cycle becomes a serious problem for patients with dry skin and dermatological conditions such as atopic dermatitis and psoriasis.

This is because excessive scratching damages your skin or causes a secondary infection (such as a fungal infection), which worsen the itching.




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Treatment of itch

Scratching might be the most convenient and effective way to remove irritants when you feel itchy from an insect bite or poisonous plant. But for strong itch stemming from other factors such as dry skin (xerosis), eczema, liver disease or kidney failure, you may have to seek medical treatment.

Your doctor will prescribe a medicated cream to apply to the site of the itch. This might be an anti-fungal cream to kill the fungus that has developed.

Using cool water, menthol or anti-itch creams can help numb the itch sensory fibers and reduce the itch intensity. Antihistamine drugs such as loratadine (brand name Claratyne) and fexofenadine (brand name Telfast) can help relieve the unrelenting itchiness caused by allergies or insect biting.

For the chronic itch associated with skin conditions, internal diseases, neurological diseases or other emotional problems, unfortunately, there is currently no effective treatment for itch as we’re not entirely sure what’s happening in the brain to cause itch in these circumstances. If itching persists or worsens, stop scratching and go see a doctor.The Conversation

Yuan Lei, Graduate Student, Institute of Neuroscience, Chinese Academy of Sciences and Yan-Gang Sun, Investigator, Institute of Neuroscience, Chinese Academy of Sciences

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

Want to improve your mood? It’s time to ditch the junk food



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Eating a healthy diet fuels our brain cells, fights inflammation and helps produce the chemicals that make us happy.
Antor Paul

Megan Lee, Southern Cross University

Worldwide, more than 300 million people live with depression. Without effective treatment, the condition can make it difficult to work and maintain relationships with family and friends.

Depression can cause sleep problems, difficulty concentrating, and a lack of interest in activities that are usually pleasurable. At its most extreme, it can lead to suicide.




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Depression has long been treated with medication and talking therapies – and they’re not going anywhere just yet. But we’re beginning to understand that increasing how much exercise we get and switching to a healthy diet can also play an important role in treating – and even preventing – depression.

So what should you eat more of, and avoid, for the sake of your mood?

Ditch junk food

Research suggests that while healthy diets can reduce the risk or severity of depression, unhealthy diets may increase the risk.

Of course, we all indulge from time to time but unhealthy diets are those that contain lots of foods that are high in energy (kilojoules) and low on nutrition. This means too much of the foods we should limit:

  • processed and takeaway foods
  • processed meats
  • fried food
  • butter
  • salt
  • potatoes
  • refined grains, such as those in white bread, pasta, cakes and pastries
  • sugary drinks and snacks.

The average Australian consumes 19 serves of junk food a week, and far fewer serves of fibre-rich fresh food and wholegrains than recommended. This leaves us overfed, undernourished and mentally worse off.

Here’s what to eat instead

Mix it up.
Anna Pelzer

Having a healthy diet means consuming a wide variety of nutritious foods every day, including:

  • fruit (two serves per day)
  • vegetables (five serves)
  • wholegrains
  • nuts
  • legumes
  • oily fish
  • dairy products
  • small quantities of meat
  • small quantities of olive oil
  • water.



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This way of eating is common in Mediterranean countries, where people have been identified as having lower rates of cognitive decline, depression and dementia.

In Japan, a diet low in processed foods and high in fresh fruit, vegetables, green tea and soy products is recognised for its protective role in mental health.

How does healthy food help?

A healthy diet is naturally high in five food types that boost our mental health in different ways:

Complex carbohydrates found in fruits, vegetables and wholegrains help fuel our brain cells. Complex carbohydrates release glucose slowly into our system, unlike simple carbohydrates (found in sugary snacks and drinks), which create energy highs and lows throughout the day. These peaks and troughs decrease feelings of happiness and negatively affect our psychological well-being.

Antioxidants in brightly coloured fruit and vegetables scavenge free radicals, eliminate oxidative stress and decrease inflammation in the brain. This in turn increases the feelgood chemicals in the brain that elevate our mood.




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Omega 3 found in oily fish and B vitamins found in some vegetables increase the production of the brain’s happiness chemicals and have been known to protect against both dementia and depression.

Salmon is an excellent source of omega 3.
Caroline Attwood

Pro and prebiotics found in yoghurt, cheese and fermented products boost the millions of bacteria living in our gut. These bacteria produce chemical messengers from the gut to the brain that influence our emotions and reactions to stressful situations.

Research suggests pro- and prebiotics could work on the same neurological pathways that antidepressants do, thereby decreasing depressed and anxious states and elevating happy emotions.

What happens when you switch to a healthy diet?

An Australian research team recently undertook the first randomised control trial studying 56 individuals with depression.

Over a 12-week period, 31 participants were given nutritional consulting sessions and asked to change from their unhealthy diets to a healthy diet. The other 25 attended social support sessions and continued their usual eating patterns.

The participants continued their existing antidepressant and talking therapies during the trial.

At the end of the trial, the depressive symptoms of the group that maintained a healthier diet significantly improved. Some 32% of participants had scores so low they no longer met the criteria for depression, compared with 8% of the control group.




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The trial was replicated by another research team, which found similar results, and supported by a recent review of all studies on dietary patterns and depression. The review found that across 41 studies, people who stuck to a healthy diet had a 24-35% lower risk of depressive symptoms than those who ate more unhealthy foods.

These findings suggest improving your diet could be a cost-effective complementary treatment for depression and could reduce your risk of developing a mental illness.The Conversation

Megan Lee, Academic Tutor and Lecturer, Southern Cross University

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

Five life lessons from your immune system



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Are you exhausted? Your immune cells might be too.
from www.shutterstock.com

Joanna Groom, Walter and Eliza Hall Institute

This article is part of our occasional long read series Zoom Out, where authors explore key ideas in science and technology in the broader context of society and humanity.


Scientists love analogies. We use them continually to communicate our scientific approaches and discoveries.

As an immunologist, it strikes me that many of our recurring analogies for a healthy, functioning immune system promote excellent behaviour traits. In this regard, we should all aim to be a little more like the cells of our immune system and emulate these characteristics in our lives and workplaces.

Here are five life lessons from your immune system.




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1. Build diverse and collaborative teams

Our adaptive immune system works in a very specific way to detect and eradicate infections and cancer. To function, it relies on effective team work.

At the centre of this immune system team sits dendritic cells. These are the sentinels and leaders of the immune system – akin to coaches, CEOs and directors.

They have usually travelled widely and have a lot of “life experience”. For a dendritic cell, this means they have detected a pathogen in the organs of the body. Perhaps they’ve come into contact with influenza virus in the lung, or encountered dengue fever virus in the skin following a mosquito bite.

Dendritic cells form a surveillance network – shown here as reddish stained cells in skin.
Ed Uthman (Houston, TX, USA) via Wikimedia Commons, CC BY

After such an experience, dendritic cells make their way to their local lymph nodes – organs structured to facilitate immune cell collaboration and teamwork.

Here, like the best leaders, dendritic cells share their life experiences and provide vision and direction for their team (multiple other cell types). This gets the immune cell team activated and working together towards a shared goal – the eradication of the pathogen in question.

The most important aspect of the dendritic cell strategy is knowing the strength of combined diverse expertise. It is essential that immune team members come from diverse backgrounds to get the best results.

To do this, dendritic cells secrete small molecules known as chemokines. Chemokines facilitate good conversations between different types of immune cells, helping dendritic cells discuss their plans with the team. In immunology, we call this “recruitment”.

This 3D image of a lymph node shows the cells that produce chemokines in red and blue.
Joanna Groom/WEHI, Author provided

Much like our workplaces, diversity is key here. It’s fair to say, if dendritic cells only recruited more dendritic cells, our immune system would completely fail its job. Dendritic cells instead hire T cells (among others) and share the critical knowledge and strategy to steer effective action of immune cells.

T cells can then pass these plans down the line – either preparing themselves to act directly on the pathogen, or working alongside other cell types, such as B cells that make protective antibodies.

In this way, dendritic cells establish a rich and diverse team that works together to clear infections or cancer.

2. Learn through positive and negative feedback

Immune cells are excellent students.

During development, T cells mature in a way that depends on both positive and negative feedback. This occurs in the thymus, an organ found in the front of your chest and whose function was first discovered by Australian scientist Jacques Miller (awarded the 2018 Japan Prize for his discoveries).




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As they mature, T cells are exposed to a process of trial and error, and take on board criticism and advice in equal measure, to ensure they are “trained” to respond appropriately to what they “see” (for example, molecules from your own body, or from a foreign pathogen) when they leave the thymus.

Importantly, this process is balanced, and T cells must receive both positive and negative feedback to mature appropriately – too much of either on its own is not enough.

In the diverse team of the immune system, cells can be both the student and the teacher. This occurs during immune responses with intense cross-talk between dendritic cells, T cells and B cells.

In this supportive environment, multiple rounds of feedback allow B cells to gain a tighter grip on infections, tailoring antibodies specifically towards each pathogen.

The result of this feedback is so powerful, it can divert cells away from acting against your own body, instead converting them into active participants of the immune system team.

Developing avenues that promote constructive feedback offers potential to correct autoimmune disorders.

The colours in this magnified slice through a lymph node show different cell types interacting as part of an immune response.
Joanna Groom/WEHI, Author provided



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3. A unique response for each situation

Our immune system knows that context is important – it doesn’t rely on a “one-size–fits-all” approach to resolve all infections.

This allows the cells of our immune system to perfectly respond to different types of pathogens: such as viruses, fungi, bacteria and helminths (worms).

In these different scenarios, even though the team members contributing to the response are the same (or similar), our immune system displays emotional intelligence and utilises different tools and strategies depending on the different situations, or pathogens, it encounters.

Importantly, our immune system needs to carefully control attack responses to get rid of danger. Being too heavy handed leaves us with collateral tissue damage, such as is seen allergy and asthma. Conversely, weak responses lead to immunodeficiencies, chronic infection or cancer.

A major research aim for people working in immunology is to learn how to harness balanced and tailored immune responses for therapeutic benefit.




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4. Focus on work/life balance

When we are overworked and poorly rested, we don’t function at our peak. The same is true for our immune cells.

An overworked immune cell is commonly referred to as being “chronically exhausted”. In this state, T cells are no longer effective at attacking tumour or virus-infected cells. They are lethargic and inefficient, much like us when we overdo it.

For T cells, this switch to exhaustion helps ensure a balanced response and avoids collateral damage. However, viruses and cancers exploit this weakness in immune responses by deliberately promoting exhaustion.

The rapidly advancing field of immunotherapy has tackled this limitation in our immune system head-on to create new cancer therapeutics. These therapies release cells of their exhaustion, refresh them, so they become effective once more.

This therapeutic avenue (called “immune checkpoint inhibition”) is like a self-care day spa for your T cells. It revives them, renewing their determination and efficiency.

This has revolutionised the way cancer is treated, leading to the award of the 2018 Nobel prize in Medicine to two of its pioneers, James P. Allison and Tasuku Honjo.




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5. Learn from life experiences

The cornerstone of our adaptive immune system is the ability to remember our past infections. In doing so, it can respond faster and in a more targeted manner when we encounter the same pathogen multiple times.

Quite literally, if it doesn’t kill you, it makes your immune system stronger.

Vaccines exploit this modus operandi, providing immune cells with the memories without the risk of infection.

Work still remains to identify the pathways that optimise formation of memory cells that drive this response. Researchers aim to discover which memories are the most efficient, and how to make them target particularly recalcitrant infections, such as malaria, HIV-AIDS and seasonal influenza.

While life might not have the shortcuts provided by vaccines, certainly taking time to reflect and learn after challenges can allow us to find better, faster solutions to future problems.




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The Conversation


Joanna Groom, Laboratory Head, Walter and Eliza Hall Institute

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

What’s behind the increase in bowel cancer among younger Australians?



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Bowel cancer was the second most commonly diagnosed cancer in Australia in 2017.
from shutterstock.com

Suzanne Mahady, Monash University; Eleonora Feletto, Cancer Council NSW, and Karen Canfell, UNSW

Bowel cancer mostly affects people over the age of 50, but recent evidence suggests it’s on the rise among younger Australians.

Our study, published recently in Cancer Epidemiology, Biomarkers and Prevention, found the incidence of bowel cancer, which includes colon and rectal cancer, has increased by up to 9% in people under 50 from the 1990s until now.

Our research examined all recorded cases of bowel cancer from the past 40 years in Australians aged 20 and over. Previous studies assessing bowel cancer incidence in young Australians have also documented an increase in the younger age group.




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Bowel cancer includes cancer of the colon and rectum.
Wikimedia Commons

This trend is also being seen internationally. A study from the United States suggests an increase in bowel cancer incidence in people aged 54 and younger. The research shows rectal cancer incidence increased by 3.2% annually from 1974 to 2013 among those aged age 20-29.

Bowel cancers are predicted to be the third most commonly diagnosed cancer in Australia this year. In 2018, Australians have a one in 13 chance of being diagnosed with bowel cancer by their 85th birthday.

Our study also found bowel cancer incidence is falling in older Australians. This is likely, in part, to reflect the efficacy of the National Bowel Cancer Screening Program, targeted at those aged 50-74. Bowel cancer screening acts to reduce cancer incidence, by detecting and removing precancerous lesions, as well as reducing mortality by detecting existing cancers early.

This is important, as bowel cancer has a good cure rate if discovered early. In 2010 to 2014, a person diagnosed with bowel cancer had a nearly 70% chance of surviving the next five years. Survival is more than 90% for people who have bowel cancer detected at an early stage.

That is why screening is so effective – and we have previously predicted that if coverage rates in the National Bowel Screening Program can be increased to 60%, around 84,000 lives could be saved by 2040. This would represent an extraordinary success. In fact, bowel screening has potential to be one of the greatest public health successes ever achieved in Australia.

Why the increase in young people?

Our study wasn’t designed to identify why bowel cancer is increasing among young people. However, there are some factors that could underpin our findings.

The increase in obesity parallels that of bowel cancer, and large population based studies have linked obesity to increased cancer risk.




Read more:
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Unhealthy lifestyle behaviours, such as increased intake of highly processed foods (including meats), have also been associated with increased bowel cancer risk. High quality studies are needed to explore this role further.

Alcohol is also thought to be a contributor to increasing the risk of bowel cancer.

Alcohol is thought to contribute to an increased risk of bowel cancer.
from shutterstock.com

So, should we be lowering the screening age in Australia to people under the age of 50?

Evaluating a cancer screening program for the general population requires a careful analysis of the potential benefits, harms, and costs.

A recent Australian study modelled the trade-offs of lowering the screening age to 45. It showed more cancers would potentially be detected. But there would also be more colonoscopy-related harms such as perforation (tearing) in an extremely small proportion of people who require further evaluation after screening.

A lower screening age would also increase the number of colonoscopies to be performed in the overstretched public health system and therefore could have the unintended consequence of lengthening colonoscopy waiting times for people at high risk.




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How to reduce bowel cancer risk

One of the most common symptoms of bowel cancer is rectal bleeding. So if you notice blood when you go to the toilet, see your doctor to have it checked out.

A healthy lifestyle including adequate exercise, avoiding smoking, limiting alcohol intake and eating well, remains most important to reducing cancer risk.

Aspirin may also lower risk of cancer, but should be discussed with your doctor because of the potential for side effects including major bleeding.

Most importantly, we need to ensure eligible Australians participate in the current evidence-based screening program. Only 41% of the population in the target 50-74 age range completed their poo tests in 2015-2016. The test is free, delivered by post and able to be self-administered.The Conversation

Suzanne Mahady, Gastroenterologist & Clinical Epidemiologist, Senior Lecturer, Monash University; Eleonora Feletto, Research fellow, Cancer Council NSW, and Karen Canfell, Adjunct professor, UNSW

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

Health Check: what causes bloating and gassiness?



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One in six healthy people report problems with bloating.
Alice Day/Shutterstock

Vincent Ho, Western Sydney University

Your trousers fit when you put them on in the morning. But come mid-afternoon, they’re uncomfortably tight – and you didn’t even overdo it at lunchtime. Sound familiar?

Around one in six people without a health problem and three in four people with irritable bowel syndrome (IBS) report problems with bloating. In fact, for people with IBS and constipation, bloating is their most troublesome symptom.




Read more:
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Bloating is, of course, a feeling of increased abdominal pressure, usually related to gas. It may or may not be accompanied by visible enlargement of the waist (known as abdominal distension).

But contrary to popular belief, bloating and abdominal distention isn’t caused by an excessive production of gas in the intestines.

What causes intestinal gas?

Gas in the upper gut can come from swallowed air, chemical reactions (from neutralising acids and alkali) triggered by food, and dissolved gas moving from the bloodstream into the gut.

Food products that are poorly absorbed in the small intestine can travel lower down to the large intestine where they’re fermented by bacteria. This process can produce carbon dioxide, hydrogen or methane gas.

Gas from the gut can come out through belching or passing wind, or by being absorbed into the blood or consumed by bacteria.

How much wind is normal?

Back in 1991, researchers in the UK tracked the farts of ten healthy volunteers. The volume of gas they expelled in a day varied from 214 mls (on a low-fibre diet) to 705 mls (on a high fibre diet).




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The participants passed wind an average of 14 to 18 times per day, and it was comprised mainly of carbon dioxide and hydrogen.

In the fasting state, the healthy gastrointestinal tract contains around 100 mls of gas which is distributed almost equally among six segments of the gut: the stomach, small intestine, ascending colon, transverse colon, descending colon and lower (pelvic) colon.


Tefi/Shutterstock

After eating, the volume of gas in the gut can increase by about 65% and tends to be located around the pelvic colon.

As the stomach stretches and small bowel is stimulated, the passage of gas accelerates and you might feel the urge to fart.

But for people with a high-fat diet, fats inside the small bowel can delay this passage and make you retain the gas.

Bloaters don’t produce more gas

A 1975 study compared the amount of intestinal gas between people who reported being bloated and those who said they were not.

The researchers pumped (inert) gas through a tube directly into the participants’ intestines at a relatively high flow of 45 mls per minute. Then they recovered the gas via a plastic tube from their rectum.

The researchers found no difference in the levels of gas collected between the bloating and healthy subjects.

Not everyone who feels bloated will have a distended stomach.
siam.pukkato/Shutterstock

More recent research using abdominal CT scans has shown that people with bloating have similar volumes of intestinal gas as those who don’t feel bloated.

Likewise, although people with IBS experience more abdominal distention, they do not produce more intestinal gas than other people.

This leads us to believe the volume of gas in the gut itself isn’t the main mechanism for bloating.

When gas gets trapped

Most people tolerate intestinal gas really well because they can propel and evacuate gas very efficiently. As a result, only a relatively small amount of gas remains inside the gut at a given time.

In one study, researchers pumped just over 1.4 litres of gas in two hours into the mid-small bowel of healthy volunteers. This led to only a very small change in waist circumference: no more than 4mm.

On the other hand, people with abdominal conditions such as IBS or functional dyspepsia (indigestion), show impaired gas transit – in other words, the gas ends up being trapped in different parts of the bowel rather than moving along easily.




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Studies show people with abdominal conditions tend to retain a relatively large proportion of gas pumped into the mid small bowel. They may even have notable increases in waist circumference without any gas being pumped in.

This impairment was confirmed in a study comparing 20 participants with IBS to a control group of 20 healthy participants. All received gas pumped directly into the mid-small bowel.

Some 90% of IBS participants retained the gas in their intestines compared to only 20% of control subjects. The researchers found abdominal distension was directly correlated with gas retention.

Some people also have problems evacuating this gas, or farting. People with IBS and chronic constipation, for instance, may have difficulty relaxing and opening their anal sphincter to release farts.

This can lead to intestinal gas retention and symptoms of bloating, abdominal pain and distension.

Pain without looking bloated

Despite feeling extremely bloated, some people have minimal or no distension of their stomach.

Research among people with IBS suggests this pain and discomfort may be due to a heightened sensitivity in the gut when a section of the abdomen stretches.

In fact, one study found those with bloating alone had more abdominal pain than those who had symptoms of bloating and abdominal distension.

If you’re sensitive to this stretching, are unable to move gas throughout your gut, and can’t get rid of it, you’re likely to have bloating and pain, whether or not there’s any visual sign.




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The Conversation


Vincent Ho, Senior Lecturer and clinical academic gastroenterologist, Western Sydney University

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

Why people born between 1966 and 1994 are at greater risk of measles – and what to do about it



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People may unknowingly bring measles back from other countries, including Europe.
Matej Kastelic/Shutterstock

Kristine Macartney, University of Sydney and Lucy Deng, University of Sydney

Australia was declared free of measles in 2014. Yet this summer we’ve seen nine cases of measles in New South Wales, and others in Victoria, Western Australia, South Australia and Queensland.

High vaccination rates in Australia means the measles virus doesn’t continuously spread, but we still have “wildfire” outbreaks when travellers bring measles into the country, often unknowingly.

If you haven’t received two doses of measles vaccine, you are at risk of contracting measles.




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How can you catch it?

Measles is a highly contagious virus that spreads by touching or breathing in the same air as an infected person. The virus stays alive in the air or on infected surfaces for up to two hours.

An infected person is contagious from the first day of symptoms (fever, cough and runny nose). These general symptoms start about four days before the rash develops, meaning contagious people can spread the virus even before they realise they have measles.

If you’re not immune to the virus, through vaccination or past infection, the chance of becoming ill after being near someone with measles is 90%. Being in the same café, waiting in line at the checkout or flying on the same aeroplane as an infected person could be enough to pick up the disease.

Why is it so dangerous?

Measles causes a fever, cough, and a rash that starts around the hairline and then spreads to the whole body.

The red rash starts around the hairline, then spreads.
Phichet Chaiyabin/Shutterstock

It can also cause middle ear infections (otitis media), chest infections (pneumonia), and diarrhoea.

Swelling and inflammation to the brain (encephalitis) occurs in 1 in every 1,000 cases and can lead to permanent brain damage or death. In 2017, 110,000 people died from measles worldwide.

Even after surviving the initial illness, measles can cause a devastating and fatal complication known as subacute sclerosing panencephalitis (inflammation of the brain) many years later.

Why are people in their 20s to 50s more at risk?

To protect yourself against measles, you need two doses of measles-mumps-rubella (MMR) vaccine.

Children in Australia routinely get this vaccine at 12 and 18 months of age. The second dose is given in combination with the chickenpox vaccine.




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It’s important to have two doses of MMR vaccine, especially if you haven’t reached your mid-50s. Most people older than this would have been infected with measles before vaccination was routine.

People aged in their 20s to early 50s (those born from 1966 and 1994) are most likely to have only had one dose of MMR vaccine.

While we’ve had the measles vaccine in Australia since 1968, a two-dose program was only introduced in 1992. A brief school-based catch-up program from 1993 to 1994 offered school children a second dose. Another school-based program provided children with catch-up vaccinations in 1998*.

For those who missed out on the school program, catch-up vaccinations were given on an ad-hoc basis via GP clinics.

So not everyone in this age group would have received two doses of the measles vaccine.

If you are this age, you may not be not fully protected against measles. Checking with a GP or immunisation nurse is the best way to be sure. They will check your records, and may do a blood test if you have no proof of immunisation.

Even if you can’t be sure of past vaccinations, it’s still safe to have an extra vaccine. And it’s free for those who need a catch-up dose.

It’s not harmful to have an additional dose of the MMR vaccine.
Shutterstock

If you have a child under 12 months of age and you’re heading to a country with measles, an early additional vaccine dose can be given to protect your baby from measles. This ideally should be done at least a month before you travel, to ensure an immune response has time to develop. The routine scheduled doses at 12 months and 18 months will still need to be given later.




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What if you’re not protected?

Unfortunately, there is no treatment for measles. Getting adequately vaccinated is the best form of defence against this serious disease.

If you think you’ve been exposed or may be ill from measles, see your GP or call Health Direct or your public health department as soon as possible.

If exposed, but not yet ill, it may not be too late to get a protective vaccine and ensure you don’t spread the disease to others.

If you are unwell, and suspect measles, call ahead to let the clinic know so they can make provisions to keep you away from other patients in the waiting room.

Other, more common, diseases can look like measles, so an urgent specific test (throat swab) must be done to confirm the infection. If measles is proven, public health workers will trace your contacts and your treating doctor will monitor you for complications.

Are we at risk of measles returning in Australia?

Australia currently has all-time high vaccine coverage, with 94.5% of five-year-old children fully immunised at the end of 2017.

By keeping vaccine coverage near or above 95%, herd immunity where there are enough people vaccinated helps prevent measles from spreading to others, including those who cannot be vaccinated.

But in our interconnected world, we must work together to reduce the threat of measles worldwide by boosting immunisation programs in regions with low coverage, including in the Asia Pacific.




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Measles have resurfaced in some countries due to falls in vaccine coverage from unfounded safety concerns as well as weak health systems. In the first six months of last year, for instance, Europe had 41,000 cases of measles, nearly double the total number of the previous year. This, among other factors, has prompted the World Health Organisation to list vaccine hesitancy as a top ten threat to global health in 2019.

A continued global coordinated effort will be required to maintain elimination and prevent resurgence of this deadly disease in Australia.

* Correction: this article has been updated to note a school-based catch-up program also operated in 1998.The Conversation

Kristine Macartney, Professor, Discipline of Paediatrics and Child Health, University of Sydney and Lucy Deng, Staff Specialist Paediatrician, National Centre for Immunisation Research and Surveillance; Clinical Associate Lecturer, Children’s Hospital Westmead Clinical School, University of Sydney

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