Health check: can eating certain foods make you smarter?



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Green vegetables, nuts and berries are among the foods that could improve our brain function.
From shutterstock.com

Margaret Morris, UNSW and Michael Kendig, UNSW

Trying to keep up with what constitutes a “healthy” diet can be exhausting. With unending options at the supermarket, and diet advice coming from all directions, filling your shopping trolley with the right things can seem an overwhelming task.

For a long time we’ve known diet is key to maintaining physical health.

But emerging evidence indicates diet quality also plays a critical role in our cognitive function.

We’re learning some of the best things to eat in this regard include vegetables, nuts and berries, foods containing “good fats” and, possibly, fermented foods.

As well as potentially improving our brain function, eating these sorts of foods could improve our mental well-being – and could even help the planet, too.




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Diet and brain function

In the face of rising obesity rates, over the past couple of decades, researchers have questioned whether increased weight, or poor diet, could influence cognition. They have since looked at what sorts of diets might impair or improve the function of our brains.

Long term follow-up studies show obesity is associated with mild impairments in several domains of cognitive function, including short-term memory, attention and decision-making.

Research has also shown short-term memory is poorer in people who report eating more saturated fat and sugar.

Conversely, the Mediterranean diet has been associated with better brain health and maintenance of cognitive abilities into older age. A Mediterranean diet is based on vegetables, whole grains, legumes and nuts, with healthy fats such as olive oil. Intake of red meat, saturated fats and sugar is limited.

A healthy diet has many elements, so let’s look at what particular foods might explain these benefits.

Vegetables, nuts and berries

Evidence indicates eating more vegetables slows the gradual decline in cognitive abilities that occurs naturally as we age.

While all veggies are likely to contribute, those in the cruciferous (Brassicaceae) family may confer particular benefits through their high fibre, folate, potassium and vitamin content. Vegetables in this family include broccoli, cauliflower, brussels sprouts, and fad favourites kale and rocket.

Interestingly, while there’s good evidence for the protective role of vegetables, there’s less evidence when it comes to fruit.

Research has shown a healthy diet can improve cognitive functions such as learning and memory.
From shutterstock.com

Berries, though, contain high levels of antioxidants. These compounds protect the body by scavenging harmful free radicals and reducing inflammation. Together these functions are likely to protect our cognitive ability.

Studies in rats, and in older people with mild cognitive impairment, indicate supplementing diets with berries improves performance in various memory tasks.

Nuts, meanwhile, are excellent sources of monounsaturated and polyunsaturated fats, minerals and vitamins. Studies in animals have shown the addition of nuts improves learning and memory. Emerging evidence in humans suggests consuming nuts within a Mediterranean-style diet improves measures of cognition, such as the capacity for verbal reasoning.

Healthy fats

Healthy diets such as the Mediterranean diet are also characterised by foods such as oily fish, avocados, olive oil and small amounts of animal-derived fats (such as from red meat).

One of our experiments in rats showed diets high in saturated fat from lard or high in sugar led to memory impairments, whereas an oil-based diet high in polyunsaturated fats didn’t.




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Importantly, rats fed these different diets did not differ in their total energy intake – only the type of fat and sugar varied.

While we can’t comment directly on the effects in humans, these findings suggest eating excess sugar, or animal-based fats, may negatively impact cognition.

Fermented foods

For thousands of years humans have prolonged the life of foods through fermentation, which increases the proportion of Lactobacillus and other healthy gut bacteria.

Kombucha and kefir are trendy right now, but other popular fermented foods include kimchi, miso, yoghurt and sauerkraut. Intake of these foods is thought to maintain the diversity of the gut microbiome.




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Interest in the potential cognitive effects of fermented foods stems from emerging evidence for the importance of the gut microbiota in cognition and health.

It’s well known that a poor diet can reduce the diversity of the gut microbiome. Our work in rats has shown the cognitive impairments produced by exposure to an unhealthy “cafeteria” diet – a Western-style diet high in saturated fat and sugar – are linked to changes in the gut microbiome.

Beyond cognition

It’s not possible to attribute “miracle” properties to one food group alone. We suggest a balanced, varied diet is the best approach to sustain not only brain health, but heart health too.

And there may be other reasons to seek out these foods. A newly published study showed eating fruit and vegetables improved mental well-being. Subjects tended to feel happier, less worried, and reported higher levels of overall life satisfaction.

The link between diet quality and better mental health is now well-established.

The recently published EAT-Lancet report adds a further compelling reason to eat healthily: the environment. This commission argued for a “planetary health” diet – akin to the Mediterranean diet – consisting of whole grains, vegetables, fruits, nuts and dairy, healthy fats, with low animal protein and few processed foods.

It is thought that shifting to such a diet, together with reducing food waste and adopting more sustainable food production systems, will minimise environmental damage and safeguard individual health.

The central message is the health of individuals and of the planet are inextricably linked, and this requires a rethink of global food systems.




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Overhauling food systems – and individual food habits – will not be simple while foods high in fat and sugar are so readily available and relatively cheap.

Nonetheless, recognising that eating well might benefit the planet, as well as the body and brain, might motivate people to change their dietary habits.The Conversation

Margaret Morris, Professor of Pharmacology, Head of Pharmacology, UNSW and Michael Kendig, Postdoctoral Research Fellow, UNSW

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

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Eat your vegetables – studies show plant-based diets are good for immunity



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We’ve been told there are many benefits of eating our veggies. Could they improve our immune system too?
From shutterstock.com

Yasmine Probst, University of Wollongong and Joel Craddock, University of Wollongong

The number of people in Australia who follow vegetarian or plant-based diets is growing rapidly. People might choose to be vegetarian for ethical, cultural or health-related reasons.

While not all vegetarians are necessarily following a healthy diet, research shows vegetarianism can have many benefits for health. One we’re learning more about is its potential to strengthen our immune systems.

We’re still working out what aspects of a vegetarian diet may be responsible for this – whether it’s the lack of meat or the emphasis on plant-based foods.

But we think the higher volume of foods including fruits, vegetables and legumes seen in vegetarian diets is likely to have a lot to do with any associated health benefits.




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What do vegetarians eat?

Vegetarian diets are comprised of combinations of fruit, vegetables, whole grains, nuts and seeds, legumes and, for some, dairy and eggs.

There are many types of vegetarian eating patterns, from vegan (no animal products) through to lacto-ovo (some animal products such as eggs and dairy). But each avoids eating meat.

There are also a few semi-vegetarian approaches which include eating small amounts of some meats. People who primarily follow a vegetarian diet but include fish are referred to as pescetarian, while those who occasionally eat other forms of meat are considered flexitarian.

Importantly, not all vegetarians follow a healthy and balanced diet. Many won’t eat the recommended daily servings of fruit and vegetables, and will consume too much junk food.

But studies show that balanced vegetarian eating patterns could be good for our immune system and the related response of the body.

Defending from attack

Our bodies are faced with daily challenges such as getting rid of toxic chemicals and defending against nasty viruses. The immune system is “switched on” in response to these attacks.

Having a healthy immune system is important, as it prevents us from becoming sick. A healthy immune system can be supported by a number of lifestyle factors including adequate sleep, healthy body weight and regular physical activity. It can also be substantially affected by the foods we eat and drink.

Some research has found following a vegetarian diet could improve our immune systems.
From shutterstock.com

People following vegetarian diets tend to have lowered levels of white blood cells, our natural defender cells. This is the case for vegetarian diets including vegan, lacto-vegetarian and lacto-ovo vegetarian.

Having very low levels of these cells is not ideal as it can affect the body’s ability to fight infection. However, having just the right number of white cells within a healthy range may reduce your chances of getting sick.

An added shield of protection

As well as helping the immune system, vegetarian diets may also help our body with a related process called inflammation. Vegetarian diets have been shown to prevent inflammation due to the antioxidant components within the foods.

Inflammation occurs when the body releases cells to attack unwanted pathogens or respond to injury. It may result in redness to an area of the body or the release of certain chemicals inside our bodies. Inflammation is a protective measure that the body uses to stay as healthy as it can.




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People who follow vegetarian diets have lower levels of some of these chemicals (called C-reactive protein and fibrinogen) compared to people following a non-vegetarian diet.

This means people maintaining a vegetarian diet long-term are at a lower risk of getting type 2 diabetes, heart disease or even some cancers. Each of these chronic diseases is associated with increased inflammation in the body. This is shown in blood tests by increased levels of C-reactive protein, as this is a signal of systemic inflammation.

The reason why vegetarians have lowered levels of inflammation remains to be fully understood.

We suspect the high amount of fruits, vegetables, whole grains, nuts and seeds are helping. These foods are full of important nutrients including fibres, vitamins, minerals and compounds called phytochemicals.

All of these nutrients have been shown to improve levels of inflammation in the long term and may influence the body’s immune response as an added bonus.

Should I switch to a vegetarian diet?

Going vegetarian may not be for everyone.

And it’s unwise to start a new eating pattern without understanding the potential impacts it can have on your health.

Vegetarian diets that are inappropriately balanced can lead to an increased risk of iron, zinc and vitamin B12 deficiencies. This can be detrimental to overall health, particularly if followed for extended periods of time.

The risks may be greater for certain groups of people who have added nutrient needs due to life stage, gender or for another health-related reason.

So vegetarian eating should always be undertaken carefully and under professional guidance, preferably that of a dietitian, to minimise these risks.




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But importantly, only 5.1% of the Australian population eat the recommended amount of fruit and vegetables – five serves of vegetables and two serves of fruit each day.

So whether you’re vegetarian or not, focusing on incorporating more plant-based foods into your diet is worthwhile. We’re constantly learning more ways this is good for your health.The Conversation

Yasmine Probst, Senior lecturer, School of Medicine, University of Wollongong and Joel Craddock, PhD Candidate, University of Wollongong

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

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.

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.

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.




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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.




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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.

Three charts on: how and what Australians eat (hint: it’s not good)



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Far too much of Australians’ diet comes from foods that have virtually no nutrients.
from shutterstock.com

Rebecca Golley, Flinders University

More than one-third of Australians’ energy intake comes from junk foods. Known as discretionary foods, these include biscuits, chips, ice-cream and alcohol. For those aged 51-70, alcoholic drinks account for more than one-fifth of discretionary food intake.

These are some of the findings from the Nutrition across the life stages report released by the Australian Institute of Health and Welfare today.

The report also shows physical activity levels are low in most age groups. Only 15% of 9-to-13-year-old girls achieve the 60-minute target. The prevalence of overweight and obesity remains high, reaching 81% for males aged 51–70.

The food intake patterns outlined in this report, together with low physical activity levels, highlight why as a country we are struggling to turn the tide on obesity rates.




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Not much change in our diets

The report shows little has changed in Australians’ overall food intake patterns between 1995 and 2011-12. There have been slight decreases in discretionary food intake, with some trends for increased intakes of grain foods and meat and alternatives.

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The message to eat more vegetables is not hitting the mark. There has been no change in vegetable intake in children and adolescents and a decrease in vegetable intake in adults since past surveys. The new data show all Australians fall well short of the recommended five serves daily. We are are closer to meeting the recommended one to two serves of fruit each day.

Australians are consuming around four serves of grains, including breads and cereals, compared to the recommended three to seven serves.

https://datawrapper.dwcdn.net/dJD6n/4/

One serve of vegetables is equivalent to ½ cup of cooked vegetables. For fruit, this is a medium apple; grains is around ½ cup of pasta. A glass of milk and 65-120g of cooked meat are the equivalent serves for dairy and its alternatives, and meat and its alternatives respectively.




Read more:
Food as medicine: why do we need to eat so many vegetables and what does a serve actually look like?


The data show a trend of lower serves of the five food groups in outer metro, regional and remote areas of Australia. Access to quality, fresh foods such as vegetables at affordable prices is a key barrier in many remote communities and can be a challenge in outer suburban and country areas of Australia.

There was also a 7-10 percentage point difference in meeting physical activity targets between major cities and regional or remote areas of Australia. Overweight and obesity levels were 53% in major cities, 57% in inner regional areas and 61% in outer regional/remote areas.

The CSIRO Healthy Diet Score compares food intake to Australian Dietary Guidelines. You can use these to see how your diet stacks up and how to improve.

Discretionary food servings

Discretionary foods are defined in guidelines as foods and drinks that are

not needed to meet nutrient requirements and do not fit into the Five Food Groups … but when consumed sometimes or in small amounts, these foods and drinks contribute to the overall enjoyment of eating.

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A serve of discretionary food is 600kJ, equivalent to six hot chips, two plain biscuits, or a small glass of wine. The guidelines advise no more than three serves of these daily – 0.5 serves for under 8-year-olds.

Since 1995, the contribution of added sugars and saturated fat to Australians’ energy intake has generally decreased. This may be a reflection of the small decrease in discretionary food intake seen for most age groups.

But across all life stages, discretionary food intakes remain well in excess of the 0-3 serves recommended. Children at 2-3 years are eating more than three servers per day, peaking at seven daily serves in 14-to-18-year-olds. The patterns remains high throughout adulthood, still more four serves per day in the 70+ group.




Read more:
Junk food packaging hijacks the same brain processes as drug and alcohol addiction


The excess intake of discretionary foods is the most concerning trend in this report. This is due to the doubleheader of their poor nutrient profile and being eaten in place of important, nutrient-rich groups such as vegetables, whole grains and dairy foods.

Our simulation modelling compared strategies to reduce discretionary food intake in the Australian population. We found cutting discretionary choice intake by half or replacing half of discretionary choices with the five food groups would have significant benefits for reducing intake of energy and so-called “risk” nutrients (sodium and added sugar), while maintaining or improving overall diet quality.

Main contributors to discretionary foods

Alcohol is often the forgotten discretionary choice. The NHMRC 2009 guidelines state:

For healthy men and women, drinking no more than two standard drinks on any day (and no more than four standard drinks on a single occasion) reduces the lifetime risk of harm from alcohol-related disease or injury.

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For adults aged 51–70, alcoholic drinks account for more than one-fifth (22%) of discretionary food intake. Alcohol intake in adults aged 51-70+ has increased since 1995. This age group includes people at the peak of their careers, retirees and older people. Stress, increased leisure time, mental health challenges and factors such as loneliness and isolation would all play a part in this complex picture.




Read more:
Four ways alcohol is bad for your health


Young children have small appetites and every bite matters. The guidelines suggest 2-to-3-year-olds should have very limited exposure to discretionary foods. In, studies the greatest levels of excess weight are seen in preschool years.

Biscuits, cakes and muffins are the key source of added sugars for young children. These are also the top source of energy and saturated fat and a key source of salt in young children. This is the time when lasting food habits and preferences are formed.


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Rebecca Golley, Associate Professor (Research) Nutrition and Dietetics, Flinders University

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

Health Check: should I take vitamin C or other supplements for my cold?



File 20180801 136673 1u5k9n7.jpg?ixlib=rb 1.1
Once you have a cold, taking vitamin C supplements won’t do anything.
From shutterstock.com

Clare Collins, University of Newcastle

Last week I had a shocking cold. Blocked nose, sore throat, and feeling poorly. This made me think about the countless vitamins and supplements on the market that promise to ease symptoms of a cold, help you recover faster, and reduce your chance of getting another cold.

When it comes to the common cold (also called upper respiratory tract infections) there is no magic cure (I wish) but some supplements may deliver very minor improvements. Here is what the latest research evidence says.




Read more:
Health Check: can you treat the common cold?


Vitamin C

For the average person, taking vitamin C does not reduce the number of colds you get, or the severity of your cold.

In terms of how long your cold lasts, some studies have looked at people taking vitamin C every day, while others have focused on participants taking it once they develop a cold.

In 30 studies comparing the length of colds in people regularly taking at least 200 milligrams of vitamin C daily, there was a consistent reduction in the duration of common cold symptoms.

However, the effect was small and equates to about half a day less in adults, and half to one day less in children. These types of studies also found a very minor reduction in the amount of time needed off work or school.

Among studies where vitamin C was only started once a cold had developed, there was no difference in duration or severity of a cold.

There are some risks to taking vitamin C supplements. They can increase the risk of kidney stones in men, and shouldn’t be taken by people with the iron storage disease haemochromatosis, as vitamin C increases iron absorption.




Read more:
Feeling worn out? You could have iron overload


Special considerations

Although in the general population vitamin C has no impact on the number of colds people get, there is an exception. For people who are very physically active – such as marathon runners, skiers and soldiers exercising in very cold conditions – vitamin C halved their chance of getting a cold.

Many people take vitamin C supplements in hope it will treat their cold.
From shutterstock.com

A few studies have also found some benefit from vitamin C supplements of at least 200 milligrams a day for preventing colds among those with pneumonia.

However, taking vitamin E supplements in combination with a high intake of vitamin C from food markedly increased the risk of pneumonia.

Zinc

A review of studies testing zinc supplements in healthy adults found starting daily supplements of at least 75 milligrams within 24 hours of the onset of a cold shortened the duration by up to two days or by about one-third. It made no difference to the severity of the cold.

There was some variability in the results across trials, with insufficient evidence related to preventing colds. Researchers suggested that for some people, the side effects such as nausea or a bad taste from zinc lozenges might outweigh the benefits.

Take care to stop zinc supplements as soon as your cold resolves because taking too much zinc can trigger a copper deficiency leading to anaemia, low white blood cell count, and memory problems.

Garlic

Only one study has tested the impact of garlic on the common cold. Researchers asked 146 people to take garlic supplements or a placebo daily for 12 weeks. They then tallied the number and duration of their colds.

The group that took garlic reported fewer colds than those who took the placebo. The duration of colds was the same in both groups, but some people had an adverse reaction to the garlic, such as a rash, or found the garlic odour unpleasant.

Because there is only one trial, we need to be cautious about recommending garlic to prevent or treat colds. We also need to be cautious about interpreting the results because the colds were tracked using self-report, which could be biased.




Read more:
Science or Snake Oil: will horseradish and garlic really ease a cold?


Probiotics

In a review of 13 trials of probiotic supplements that included more than 3,700 children, adults and older adults, those taking supplements were less likely to get a cold.

Their colds were also likely to be of shorter duration and less severe, in terms of the number of school or work days missed.

There is some evidence that probiotics, which can be found in yoghurt, may reduce the incidence of colds.
From shutterstock.com

Most supplements were milk-based products such as yoghurt. Only three studies used powders, while two used capsules.

The quality of the all the probiotic studies, however, was very poor, with bias and limitations. This means the results need to be interpreted with caution.

Echinacea

Echinacea is a group of flowering plants commonly found in North America. These days you can buy echinacea products in capsules, tablets or drops.

A review of echinacea products found they provide no benefit in treating colds. However, the authors indicated some echinacea products may possibly have a weak benefit, and further research is needed.

Chicken soup

Yep, I’ve saved the best until last.

In a novel experiment on 15 healthy adults, researchers measured the participants’ nasal mucus flow velocity – our ability to break down and expel mucus to breathe more clearly. They tested how runny participants’ noses were after sipping either hot water, hot chicken soup or cold water, or sucking them through a straw.

Sipping hot water or chicken soup made participants’ noses run more than cold water, but sipping chicken soup worked the best. The researchers attributed this to the chicken soup stimulating smell and/or taste receptors, which then increased nasal mucus flow.

Another study on chicken soup found it can help fight infection and recovery from respiratory tract infections.

The ConversationOther researchers have shown comfort foods, such as chicken soup, can help us feel better.

Clare Collins, Professor in Nutrition and Dietetics, University of Newcastle

This article was originally published on The Conversation. Read the original article.

Food as medicine: why do we need to eat so many vegetables and what does a serve actually look like?


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Why do we need so many serves of vegetables in a day?
Unsplash/Jonathan Pielmayer, CC BY-SA

Genevieve James-Martin, CSIRO; Gemma Williams, CSIRO, and Malcolm Riley, CSIRO

This is the first article in a three-part package “food as medicine”, exploring how food prevents and cures disease. The Conversation


Most Australian adults would know they’re meant to eat two or more serves of fruit and five or more serves of vegetables every day. Whether or not they get there is another question.

A recent national survey reported 45% of Australian women and 56% of Australian men didn’t eat enough fruit. And 90% of women and 96% of men didn’t eat enough vegetables. This figure is worse than for the preceding ten years.

Men had on average 1.6 serves of fruit and 2.3 serves of vegetables per day, and women had 1.8 serves of fruit and 2.5 serves of vegetables. A serve of fresh fruit is a medium piece (about 150 grams) and a serve of vegetables is half a cup of cooked vegetables or about a cup of salad.


The Conversation/Australian Dietary Guidelines, 2013, CC BY-ND

Why do we need so many veggies?

A high intake of fruit and vegetables lowers the risk of type 2 diabetes, heart disease, stroke and some cancers. These chronic diseases are unfortunately common – it’s been estimated A$269 million could have been saved in 2008 if everyone in Australia met fruit and vegetable recommendations.

The recommendation to include plenty of vegetables and fruit in our diet is based on a large body of evidence showing the risk of a range of health conditions is reduced as we eat more fruit and vegetables. The specific targets of two serves for fruit and five to six serves for vegetables are largely based on nutrient requirements for healthy people and what diets usually look like for the average Australian.

So to set these guidelines, certain assumptions are made about dietary practices, such as breakfast being based around cereal/grain and dairy foods, and main meals being comprised of meat and vegetables, usually with a side of something starchy like rice, pasta or the humble potato – an Australian staple.

Does this mean it’s the only pattern to meet all the nutrient requirements? No. Could an adult be equally healthy if they ate three serves of fruit and four serves of vegetables? Yes, probably.

Some recent research even suggests our current targets don’t go far enough. It estimates an optimal intake for reducing our risk of heart disease and early death to be around ten serves of fruit and vegetables a day. Whether we are aiming for two and five, or ten serves, is somewhat academic – the clear message is most of us need to increase our fruit and vegetable intake.

Aussies eat more potatoes than any other veggie.
Agence Producteurs Locaux Damien Kühn/Unsplash, CC BY

Why is two and five such a hard ask?

The populations of most Western countries report eating far less fruit and vegetables than they’re supposed to. So what’s making it so hard for us to get to two and five?

Diets higher in fat, sugar and grains are generally more affordable than the recommended healthy diets high in fruit and veg. In fact, for Australians on low incomes, a healthy food basket for a fortnight would cost 28 to 34% of their income, up to twice the national average for food expenditure.

As a result, people with limited access to food for financial reasons often choose foods with high energy content (because they are filling) over those with high nutritional value but low energy content like fruit and vegetables. These high-energy foods are also easy to over-consume and this may be a contributing factor to weight gain. People who are poorer generally have a diet poorer in quality but not lower in energy content, which contributes to a higher rate of obesity, particularly in women.

Fresh fruit and vegetables cost more to purchase on a dollars per kilojoule basis, and also perish more quickly than processed foods. They take more time and skill to prepare and, after all of that effort, if they don’t get eaten for reasons of personal preference, they go to waste. For many it may not stack up financially to fill the fridge with fruit and vegetables. Under these circumstances, pre-prepared or fast food, which the family is sure to eat without complaint or waste, is all too convenient.

How we can increase veggie intake

The home and school environments are two key influencers of children’s food preferences and intakes. Parents are the “food gatekeepers” and role models particularly for younger children. Where there is parental encouragement, role modelling and family rules, there is an increased fruit and vegetable intake.

Dietary behaviours and food choices often start in childhood and continue through adolescence to adulthood. So encouraging fruit and vegetable intake in schools by mechanisms such as “fruit snack times” may be a good investment.

Policy approaches include subsidies on healthy foods. Other examples include levying a tax on foods of low nutritional value, improved food labelling, and stricter controls on the marketing of unhealthy foods. In Australia debate continues around a tax on sugar-sweetened beverages, which could be used to subsidise healthy foods such as fruit and vegetables.

Research has found the more variety in fruit and vegetables available, the more we’ll consume. Those who meet the vegetable recommendation are more likely to report having at least three vegetable varieties at their evening meal. So increasing the number of different vegetables at the main meal is one simple strategy to increase intake.

This could be made a journey of discovery by adding one new vegetable to the household food supply each week. Buying “in season” fruit and vegetables and supplementing fresh varieties with frozen and canned options can bring down the total cost. Then it’s a matter of exploring simple, quick and tasty ways to prepare them so they become preferred foods for the family.

Genevieve James-Martin, Research Dietitian, CSIRO; Gemma Williams, Research Dietitian, CSIRO, and Malcolm Riley, Nutrition Epidemiologist, CSIRO

This article was originally published on The Conversation. Read the original article.