Is coconut water good for you? We asked five experts



Nutritionally, coconut water is OK, but it’s healthier to stick to plain water.
from http://www.shutterstock.com

Alexandra Hansen, The Conversation

In recent years coconut water has left the palm-treed shores of tropical islands where tourists on lounge chairs stick straws straight into the fruit, and exploded onto supermarket shelves – helped along by beverage giants such as Coca-Cola and PepsiCo.

Marketed as a natural health drink, brands spout various health claims promoting coconut water. So before we drank the Kool-Aid, we thought we’d check in with the experts whether the nutritional claims stack up. Is coconut water part of a healthy diet or we should just stick to good old water from the tap?

We asked five experts if coconut water is good for you.

Four out of five experts said no

Here are their detailed responses:


If you have a “yes or no” health question you’d like posed to Five Experts, email your suggestion to: alexandra.hansen@theconversation.edu.au


Clare Collins is affiliated with the Priority Research Centre for Physical Activity and Nutrition, the University of Newcastle, NSW. She is an NHMRC Senior Research and Gladys M Brawn Research Fellow. She has received research grants from NHMRC, ARC, Hunter Medical Research Institute, Meat and Livestock Australia, Diabetes Australia, Heart Foundation, Bill and Melinda Gates Foundation, nib foundation, Rijk Zwaan Australia and Greater Charitable Foundation. She has consulted to SHINE Australia, Novo Nordisk, Quality Bakers, the Sax Institute and the ABC. She was a team member conducting systematic reviews to inform the Australian Dietary Guidelines update and the Heart Foundation evidence reviews on meat and dietary patterns. Emma Beckett is a member of the Nutrition Society of Australia, Australian Institute for Food Science and Technology. Her research is funded by the NHMRC and AMP Foundation. She has previously consulted for Kellogg’s. Rebecca Reynolds is a registered nutritionist and the owner of The Real Bok Choy, a nutrition and lifestyle consultancy.The Conversation

Alexandra Hansen, Chief of Staff, The Conversation

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

Will a vegetarian diet increase your risk of stroke?



This is the first study to link a vegetarian diet to an increased risk of stroke. But the evidence isn’t strong enough to cause alarm.
From shutterstock.com

Evangeline Mantzioris, University of South Australia

Research Checks interrogate newly published studies and how they’re reported in the media. The analysis is undertaken by one or more academics not involved with the study, and reviewed by another, to make sure it’s accurate.

A UK study finding vegetarianism is associated with a higher risk of stroke than a meat-eating diet has made headlines around the world.

The study, published in the British Medical Journal last week, found people who followed vegetarian or vegan diets had a 20% higher risk of having a stroke compared to those who ate meat.

But if you’re a vegetarian, there’s no need to panic. And if you’re a meat eater, these results don’t suggest you should eat more meat.

While we don’t fully understand why these results occurred, it’s important to note the study only showed an association between a vegetarian diet and increased stroke risk – not direct cause and effect.




Read more:
Clearing up confusion between correlation and causation


What the study did and found

The researchers looked at 48,188 men and women living in Oxford, following what they ate, and whether they had heart disease or a stroke, over 18 years. The researchers grouped the participants according to their diets: meat eaters, fish eaters (pescatarians) and vegetarians (including vegans).

While vegan diets are quite different to vegetarian diets, the investigators combined these two groups as there were very small numbers of vegans in the study.

In their analysis, the researchers accounted for variables which are known risk factors for heart disease and stroke, including education level, smoking status, alcohol consumption, and physical activity.




Read more:
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They found vegetarians had a 22% lower risk of heart disease than meat eaters. This is equivalent to ten fewer cases of heart disease per 1,000 vegetarians than in meat eaters over ten years.

Yet the vegetarians had a 20% higher rate of stroke, equivalent to three more strokes per 1,000 vegetarians compared to the meat eaters over ten years.

The decrease in heart disease risk seemed to be linked to lower body mass index (BMI), cholesterol levels, incidence of diabetes, and blood pressure. These benefits are all known to be associated with a healthy vegetarian diet, and are protective factors
against heart disease.

This study showed fish eaters (who did not consume meat) had a 13% lower risk of heart disease, but no significant increase in the rate of stroke when compared to meat eaters.

As with any study, there are strengths and weaknesses

The main strength of this study is that it closely followed a very large group of people over a long period of time.

The major weakness is that being an observational study, the researchers were not able to determine a cause and effect relationship.

So this study is not showing us vegetarian diets lead to increased risk of stroke; it simply tells us vegetarians have an increased risk of stroke. This means the association may be linked to other factors, aside from diet, which may be related to the lifestyle of a vegetarian.

The study’s authors suggest a difference in vitamin B12 levels between the vegetarian and meat-eating groups may have contributed to the results.
From shutterstock.com

And while vegetarian and vegan diets may be seen as generally healthier, vegetarians still may be eating processed and ultra-processed foods. These foods can contain high levels of added salt, trans fat and saturated fats. This study did not report on the whole dietary pattern – just the major food groups.

Another major weakness of this study is that vegans and vegetarians were grouped together. Vegetarian and vegan diets can vary considerably in nutrient levels.

So why would the vegetarian group have a higher stroke risk?

These kind of observational studies are unable to provide what scientists call “a mechanism” – that is, a biological explanation as to why this association may exist.

But researchers will sometimes offer a potential biological explanation. In this case, they suggest the differences in nutrient intakes between the different diets may go some way to explaining the increased risk of stroke in the vegetarian group.

They cite a number of Japanese studies which have shown links between a very low intake of animal products and an increased risk of stroke.




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


One nutrient they mention is vitamin B12, as it’s found only in animal products (meat, fish, dairy products and eggs). Vegan sources are limited, though some mushroom varieties and fermented beans may contain vitamin B12.

Vitamin B12 deficiency can lead to anaemia and neurological issues, including numbness and tingling, and cognitive difficulties.

The authors suggest a lack of vitamin B12 may be linked to the increased risk of stroke among the vegetarian group. This deficiency could be present in vegetarians, and even more pronounced in vegans.

But this is largely speculative, and any associations between a low intake of animal products and an increased risk of stroke remain to be founded in a strong body of evidence. More research is needed before any recommendations are made.

What does this mean for vegetarians and vegans?

Vegetarians and vegans shouldn’t see this study as a reason to change their diets. This is the only study to date to have shown an increased risk of stroke with vegetarian or vegan diets.

Further, this study has shown overall greater benefits are gained by being vegetarian or vegan in its association with reduced risk of heart disease.

Meanwhile, other studies have shown meat eaters – particularly people who eat large amounts of red and processed meats – have higher risk of certain cancers.




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Whether you’re an omnivore, pescatarian, vegetarian or vegan, it’s important to consider the quality of your diet. Focus on eating whole foods, and including lots of vegetables, fruits, cereals and grains.

It’s equally important to minimise the intake of processed foods high in added sugars, salt, saturated and trans fats. Diets high in these sorts of foods have well-established links to increased risk of heart disease and stroke. –Evangeline Mantzioris


Blind peer review

The analysis presents a fair and balanced assessment of the study, accurately pointing out that no meaningful recommendations can be drawn from the results. This is particularly so since the majority of the data was collected via self-reported questionnaires, which reduces the reliability of the results.

While in many cases the media has reported an increased stroke risk in vegetarians, total stroke risk was not actually statistically different between the groups. The researchers looked at two types of stroke: ischaemic stroke (where a blood vessel supplying blood to the brain is obstructed) and haemorrhagic stroke (where a blood vessel leaks or breaks).

A statistically significant increased risk in the vegetarian group was only seen in haemorrhagic stroke – and even there it’s marginal. Statistically, and in total numbers of people affected, the reduced heart disease risk in the vegetarian group is more convincing. –Andrew CareyThe Conversation

Evangeline Mantzioris, Program Director of Nutrition and Food Sciences, University of South Australia

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

Here’s what you can eat and avoid to reduce your risk of bowel cancer



It’s not certain why, but fibre has protective effects against bowel cancer.
http://www.shutterstock.com

Suzanne Mahady, Monash University

Australia has one of the highest rates of bowel cancer in the world. In 2017, bowel cancer was the second most common cancer in Australia and rates are increasing in people under 50.

Up to 35% of cancers worldwide might be caused by lifestyle factors such as diet and smoking. So how can we go about reducing our risk of bowel cancer?




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


What to eat

Based on current evidence, a high fibre diet is important to reduce bowel cancer risk. Fibre can be divided into 2 types: insoluble fibre, which creates a bulky stool that can be easily passed along the bowel; and soluble fibre, which draws in water to keep the stool soft.

Fibre from cereal and wholegrains is an ideal fibre source. Australian guidelines suggest aiming for 30g of fibre per day for adults, but fewer than 20% of Australian adults meet that target.

Wheat bran is one of the richest sources of fibre, and in an Australian trial in people at high risk of bowel cancer, 25g of wheat bran reduced precancerous growths. Wheat bran can be added to cooking, smoothies and your usual cereal.

It’s not clear how fibre may reduce bowel cancer risk but possible mechanisms include reducing the time it takes food to pass through the gut (and therefore exposure to potential carcinogens), or through a beneficial effect on gut bacteria.

Once bowel cancer is diagnosed, a high fibre diet has also been associated with improved survival.

Dairy is ‘probably’ protective against bowel cancer.
from http://www.shutterstock.com



Read more:
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Milk and dairy products are also thought to reduce bowel cancer risk. The evidence for milk is graded as “probably protective” in current Australian bowel cancer guidelines, with the benefit increasing with higher amounts.

Oily fish may also have some protective elements. In people with hereditary conditions that make them prone to developing lots of precancerous growths (polyps) in the bowel, a trial where one group received a daily supplement of an omega 3 polyunsaturated fatty acid (found in fish oil) and one group received a placebo, found that this supplement was associated with reduced polyp growth. Whether this is also true for people at average risk of bowel cancer, which is most of the population, is unknown.

And while only an observational study (meaning it only shows a correlation, and not that one caused the other), a study of bowel cancer patients showed improved survival was associated with daily consumption of coffee.

What to avoid

It’s best to avoid large quantities of meat. International cancer authorities affirm there is convincing evidence for a relationship between high meat intake and bowel cancer. This includes red meat, derived from mammalian muscle such as beef, veal, lamb, pork and goat, and processed meat such as ham, bacon and sausages.

Processed meats have undergone a preservation technique such as smoking, salting or the addition of chemical preservatives which are associated with the production of compounds that may be carcinogenic.

Evidence also suggests a “dose-response” relationship, with cancer risk rising with increasing meat intake, particularly processed meats. Current Australian guidelines suggest minimising intake of processed meats as much as possible, and eating only moderate amounts of red meat (up to 100g per day).

What else can I do to reduce the risk of bowel cancer?

The key to reducing cancer risk is leading an overall healthy lifestyle. Adequate physical activity and avoiding excess fat around the tummy area is important. Other unhealthy lifestyle behaviours such as eating lots of processed foods have been associated with increased cancer risk.

And for Australians over 50, participating in the National Bowel Cancer Screening program is one of the most effective, and evidence-based ways, to reduce your risk.




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The Conversation


Suzanne Mahady, Gastroenterologist & Clinical Epidemiologist, Senior Lecturer, Monash University

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

Why full-fat milk is now OK if you’re healthy, but reduced-fat dairy is still best if you’re not



The Heart Foundation now backs full-fat milk if you’re healthy. But it still recommends reduced-fat milk if you have high blood pressure or heart disease.
from www.shutterstock.com

Clare Collins, University of Newcastle

The Heart Foundation now recommends full-fat milk, cheese and yoghurt or reduced-fat options as part of its updated dietary advice released yesterday.

This moves away from earlier advice that recommended only reduced-fat dairy when it comes to heart health.

So, what’s behind the latest change? And what does this mean for people with high blood pressure or existing heart disease?




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What’s new if you’re healthy?

For healthy Australians, the Heart Foundation now recommends unflavoured full-fat milk, yoghurt and cheese, as well as the reduced-fat options previously recommended.

The change comes after reviewing research from systematic reviews and meta-analyses published since 2009. These pooled results come from mostly long-term observational studies.

This is where researchers assess people’s dietary patterns and follow them for many years to look at health differences between people who eat and drink a lot of dairy products and those who consume small amounts.

Researchers run these studies because it is not practical or ethical to put people on experimental diets for 20 or more years and wait to see who gets heart disease.




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So when results of the recent studies were grouped together, the Heart Foundation reported no consistent relationship between full-fat or reduced-fat milk, cheese and yoghurt consumption and the risk of heart disease. The risk was neither increased nor decreased.

Put simply, for people who do not have any risk factors for heart disease, including those in the healthy weight range, choosing reduced-fat or low-fat options for milk, yoghurt and cheese does not confer extra health benefits or risks compared to choosing the higher fat options, as part of a varied healthy eating pattern.




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Before you think about having a dairy binge, the review noted the studies on full-fat milk, yoghurt and cheese can’t be extrapolated to butter, cream, ice cream and dairy-based desserts.

This is why the Heart Foundation still doesn’t recommend those other full-fat dairy options, even if you’re currently healthy.

What about people with heart disease?

However, for people with heart disease, high blood pressure or some other conditions, the advice is different.

The review found dairy fat in butter seems to raise LDL or “bad” cholesterol levels more than full-fat milk, cheese and yogurt. And for people with raised LDL cholesterol there is a bigger increase in LDL after consuming fat from dairy products.




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So, for people with high blood cholesterol or existing heart disease, the Heart Foundation recommends unflavoured reduced-fat milk, yoghurt and cheese to help lower their total risk of heart disease, which is consistent with previous recommendations.

Unflavoured, reduced-fat versions are lower in total kilojoules than the full-fat options. So, this will also help lower total energy intakes, a key strategy for managing weight.

Reduced-fat yoghurt and other dairy products are still recommended for people with high cholesterol or existing heart disease.
from www.shutterstock.com

How does this compare with other advice?

The 2013 National Health and Medical Research Council’s Dietary Guidelines for Australians recommends a variety of healthy foods from the key healthy food groups to achieve a range of measures of good health and well-being, not just heart health.

Based on evidence until 2009, the guidelines generally recommend people aged over two years mostly consume reduced-fat versions of milk, yoghurt, cheese and/or their alternatives, recognising most Australians are overweight or obese.




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This advice still holds for people with heart disease. However, the new Heart Foundation advice for healthy people means less emphasis is now on using reduced-fat versions, in light of more recent evidence.

The Australian Dietary Guidelines have a further recommendation to limit eating and drinking foods containing saturated fat. The guidelines recommend replacing high-fat foods which contain mainly saturated fats such as butter and cream, with foods which contain mainly polyunsaturated and monounsaturated fats such as oils, spreads, avocado, nut butters and nut pastes.

This advice is still consistent with the Heart Foundation recommendations.

Australians eat a lot of ‘junk’ food

The most recent (2011-12) National Nutrition Survey of Australians found over one-third (35%) of what we eat comes from energy-dense, nutrient-poor, discretionary foods, or, junk foods.

Poor dietary patterns are the third largest contributor to Australia’s current burden of disease. Being overweight or obese is the second largest contributor, after smoking.

If Australians followed current dietary guidelines, whether using full- or reduced-fat milk, yoghurt and cheese, the national burden of disease due to heart disease would drop by 62%, stroke by 34% and type 2 diabetes by 41%.

What’s the take home message?

See your GP for a heart health check. If you do not have heart disease and prefer full-fat milk, cheese and yoghurt then choose them, or a mix of full and reduced-fat versions.

If you have heart disease or are trying to manage your weight then choose mostly reduced-fat versions.

Focus on making healthy choices across all food groups. If you need personalised advice, ask your GP to refer you to an accredited practising dietitian.The Conversation

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

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

Are there certain foods you can eat to reduce your risk of Alzheimer’s disease?



Eating healthy foods doesn’t just improve our physical health. It can benefit our mental health, too.
From shutterstock.com

Ralph Martins, Macquarie University

With the rise of fad diets, “superfoods”, and a growing range of dietary supplement choices, it’s sometimes hard to know what to eat.

This can be particularly relevant as we grow older, and are trying to make the best choices to minimise the risk of health problems such as high blood pressure, obesity, type 2 diabetes, and heart (cardiovascular) problems.

We now have evidence these health problems also all affect brain function: they increase nerve degeneration in the brain, leading to a higher risk of Alzheimer’s disease and other brain conditions including vascular dementia and Parkinson’s disease.

We know a healthy diet can protect against conditions like type 2 diabetes, obesity and heart disease. Fortunately, evidence shows that what’s good for the body is generally also good for the brain.




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Oxidative stress

As we age, our metabolism becomes less efficient, and is less able to get rid of compounds generated from what’s called “oxidative stress”.

The body’s normal chemical reactions can sometimes cause chemical damage, or generate side-products known as free radicals – which in turn cause damage to other chemicals in the body.

To neutralise these free radicals, our bodies draw on protective mechanisms, in the form of antioxidants or specific proteins. But as we get older, these systems become less efficient. When your body can no longer neutralise the free radical damage, it’s under oxidative stress.

The toxic compounds generated by oxidative stress steadily build up, slowly damaging the brain and eventually leading to symptoms of Alzheimer’s disease.




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To reduce your risk, you need to reduce oxidative stress and the long-term inflammation it can cause.

Increasing physical activity is important. But here we are focusing on diet, which is our major source of ANTIoxidants.

Foods to add

There are plenty of foods you can include in your diet that will positively influence brain health. These include fresh fruits, seafood, green leafy vegetables, pulses (including beans, lentils and peas), as well as nuts and healthy oils.

Fish

Fish is a good source of complete protein. Importantly, oily fish in particular is rich in omega-3 fatty acids.

Laboratory studies have shown omega-3 fatty acids protect against oxidative stress, and they’ve been found to be lacking in the brains of people with Alzheimer’s disease.

They are essential for memory, learning and cognitive processes, and improve the gut microbiota and function.

Oily fish, like salmon, is high in omega-3 fatty acids, which research shows can benefit our brain health.
From shutterstock.com

Low dietary intake of omega-3 fatty acids, meanwhile, is linked to faster cognitive decline, and the development of preclinical Alzheimer’s disease (changes in the brain that can be seen several years before for onset of symptoms such as memory loss).

Omega-3 fatty acids are generally lacking in western diets, and this has been linked to reduced brain cell health and function.

Fish also provides vitamin D. This is important because a lack of vitamin D has been linked to Alzheimer’s disease, Parkinson’s disease, and vascular dementia (a common form of dementia caused by reduced blood supply to the brain as a result of a series of small strokes).

Berries

Berries are especially high in the antioxidants vitamin C (strawberries), anthocyanins (blueberries, raspberries and blackberries) and resveratrol (blueberries).

In research conducted on mouse brain cells, anthocyanins have been associated with lower toxic Alzheimer’s disease-related protein changes, and reduced signs of oxidative stress and inflammation specifically related to brain cell (neuron) damage. Human studies have shown improvements in brain function and blood flow, and signs of reduced brain inflammation.




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Red and purple sweet potato

Longevity has been associated with a small number of traditional diets, and one of these is the diet of the Okinawan people of Japan. The starchy staple of their diet is the purple sweet potato – rich in anthocyanin antioxidants.

Studies in mice have shown this potato’s anthocyanins protect against the effects of obesity on blood sugar regulation and cognitive function, and can reduce obesity-induced brain inflammation.

Green vegetables and herbs

The traditional Mediterranean diet has also been studied for its links to longevity and lower risk of Alzheimer’s disease.

Green vegetables and herbs feature prominently in this diet. They are rich sources of antioxidants including vitamins A and C, folate, polyphenols such as apigenin, and the carotenoid xanthophylls (especially if raw). A carotenoid is an orange or red pigment commonly found in carrots.

Green vegetables and herbs provide us with several types of antioxidants.
From shutterstock.com

The antioxidants and anti-inflammatory chemicals in the vegetables are believed to be responsible for slowing Alzheimer’s pathology development, the build up of specific proteins which are toxic to brain cells.

Parsley is rich in apigenin, a powerful antioxidant. It readily crosses the barrier between the blood and the brain (unlike many drugs), where it reduces inflammation and oxidative stress, and helps brain tissue recovery after injury.




Read more:
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Beetroot

Beetroot is a rich source of folate and polyphenol antioxidants, as well as copper and manganese. In particular, beetroot is rich in betalain pigments, which reduce oxidative stress and have anti-inflammatory properties.

Due to its nitrate content, beetroot can also boost the body’s nitric oxide levels. Nitric oxide relaxes blood vessels resulting in lowered blood pressure, a benefit which has been associated with drinking beetroot juice.

A recent review of clinical studies in older adults also indicated clear benefits of nitrate-rich beetroot juice on the health of our hearts and blood vessels.

Foods to reduce

Equally as important as adding good sources of antioxidants to your diet is minimising foods that are unhealthy: some foods contain damaged fats and proteins, which are major sources of oxidative stress and inflammation.

A high intake of “junk foods” including sweets, soft drinks, refined carbohydrates, processed meats and deep fried foods has been linked to obesity, type 2 diabetes and cardiovascular disease.

Where these conditions are are all risk factors for cognitive decline and Alzheimer’s disease, they should be kept to a minimum to reduce health risks and improve longevity.




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The Conversation


Ralph Martins, Professor, Department of Biomedical Sciences, Macquarie University

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

Research Check: can drinking coffee help you lose weight?



As keen as we may be to hear about any health benefits of drinking coffee, the headlines aren’t always what they seem.
Janko Ferlic/Unsplash

Andrew Carey, Baker Heart and Diabetes Institute

Researchers from the University of Nottingham in the UK recently published a study in the journal Scientific Reports suggesting caffeine increases brown fat.

This caught people’s attention because brown fat activity burns energy, which may help with weight loss. Headlines claimed drinking coffee can help you lose weight, and that coffee is possibly even the “secret to fighting obesity”.

Unfortunately, it’s a little more complicated than that. The researchers did find caffeine stimulated brown fat, but this was mainly in cells in a lab.

For a human to reap the benefits seen in the cells, we estimate they’d need to drink at least 100 cups of coffee.

Although part of this research did look at people, the methods used don’t support coffee or caffeine as weight-loss options.




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What is brown fat?

Brown adipose (fat) tissue is found deep within the torso and neck. It contains fat cell types which differ from the “white” fat we find around our waistlines.

Brown fat cells adapt to our environment by increasing or decreasing the amount of energy they can burn when “activated”, to produce heat to warm us up.

When people are cold for days or weeks, their brown fat gets better at burning energy.

We understand caffeine may be able to indirectly accentuate and prolong some of these processes, mimicking the effects of cold exposure in stimulating brown fat.

Brown fat – and anything thought to increase its activity – has generated significant research interest, in the hope it might assist in the treatment of obesity.

What did the researchers do in this latest study?

The research team first conducted experiments where cells taken from mice were grown into fat cells in petri dishes. They added caffeine to some samples, but not others, to see whether the caffeinated cells acquired more brown fat attributes (we call this “browning”).

The dose of caffeine (one millimolar) was determined based on what would be the highest concentration that browned the cells but didn’t kill them.

The fat cell culture experiment showed adding caffeine did “brown” the cells.




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Can ‘brown fat’ really help with weight loss?


The researchers then recruited a group of nine people who drank a cup of instant coffee, or water as a control.

Before and after the participants drank coffee, the researchers measured their brown fat activity by assessing the temperature of the skin near the neck, under which a major region of brown fat is known to lie.

Skin temperature increased over the shoulder area after drinking coffee, whereas it didn’t after drinking only water.

How should we interpret the results?

Some people will criticise the low number of human participants (nine). We shouldn’t make broad recommendations on human behaviour or medicine based on small studies like this, but we can use them to identify new and interesting aspects of how our bodies work – and that’s what these researchers sought to do.

But whether the increased skin temperature after drinking coffee is significant cannot be determined for a few important reasons.

Firstly, although the study showed an increase in skin temperature after drinking coffee, the statistical analysis for the human experiment doesn’t include enough data to accurately compare the coffee and water groups, which prevents meaningful conclusions. That is, it doesn’t use appropriate methods we apply in science to decide if something really changed or only happened by chance.

Enjoy coffee for the taste, or the buzz. But don’t expect it to affect your waistline.
From shutterstock.com

Second, measuring skin temperature is not necessarily the most accurate indicator for brown fat in this context. Skin temperature has been validated as a way to measure brown fat after cold exposure, but not after taking drugs which mimic the effects of cold exposure – which caffeine is in the context of this study.

Myself and other researchers have shown the effects of these “mimic” drugs result in diverse effects including increased blood flow to the skin. Where we don’t know if changes in the skin temperature are due to brown fat or unrelated factors, relying on this measure may be problematic.

Although also suffering its own limitations, PET (poistron emission tomography) imaging is currently our best option for directly measuring active brown fat.

It’s the dose that matters most

The instant coffee used in the study contained 65mg of caffeine, which is standard for a regular cup of instant coffee. Brewed coffees vary and might be double this.

Regardless, it’s difficult to imagine this dose could increase brown fat energy burning when studies using large doses of more potent “cold-mimicking” drugs (such as ephedrine) cause no, or at best modest, increases in brown fat activity.




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But let’s look at the caffeine dose used in the cell experiments. The one millimolar concentration of caffeine is a 20-fold larger dose than 300-600mg of caffeine dose used by elite athletes as a performance-boosting strategy. And this dose is five to ten times higher than the amount of caffeine you’d get from drinking an instant coffee.

Rough calculations therefore suggest we’d need to drink 100 or 200 cups of coffee to engage the “browning” effects of caffeine.

So people should continue to drink and enjoy their coffee. But current evidence suggests we shouldn’t start thinking about it as a weight loss tool, nor that it has anything meaningful to do with brown fat in humans. – Andrew Carey


Blind peer review

This Research Check is a fair and balanced discussion of the study. The limitations identified by this Research Check apply equally to diabetes, which the study encompassed, but didn’t get picked up as much in the headlines.

Coffee contains more than caffeine, and while there is some evidence that modest coffee consumption may reduce diabetes risk, decaffeinated coffee seems to be as effective as caffeinated coffee. This is consistent with the point made by the Research Check that you would need to drink an implausible number of cups of coffee to produce the effect seen with caffeine in the cultured fat cells. – Ian Musgrave


Research Checks interrogate newly published studies and how they’re reported in the media. The analysis is undertaken by one or more academics not involved with the study, and reviewed by another, to make sure it’s accurate.The Conversation

Andrew Carey, Group Leader: Metabolic and Vascular Physiology, Baker Heart and Diabetes Institute

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

Health Check: why do we crave comfort food in winter?



You’re not imagining it. Our bodies really do crave macaroni cheese and other comfort foods as the temperature drops. Here’s why.
from www.shutterstock.com

Megan Lee, Southern Cross University and Jacqui Yoxall, Southern Cross University

It’s winter and many of us find ourselves drawn to bowls of cheesy pasta, oozing puddings, warming soups, and hot chocolate with marshmallows.

These and other comfort foods can make us feel good. But why? And why do we crave them in winter and not in summer?

Research tells us there are three good reasons.




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1. The gut ‘speaks’ to the brain

We know from the relatively new field of nutritional psychiatry that our stomachs produce the “happiness chemicals” dopamine and serotonin. When we eat, a complex process involving the brain means these neurochemicals trigger feelings of happiness and well-being.

These happiness chemicals are also produced when we exercise and are exposed to sunlight, which decline in winter.

This results in a change in the fine balance between the good and bad bacteria that live in our stomachs, and consequently, the relationship between the gut and the brain.

So, in winter when we eat our favourite comfort foods, we get a rush of happiness chemicals sent from the gut to our brain and this make us feel happy and content.




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2. Evolution may have a hand

The second reason we crave more comfort foods during the winter months could be evolutionary. Before we enjoyed technological advances such as housing, heating, supermarkets and clothing, humans who increased their body weight during winter to keep warm were more likely to survive their environmental conditions. Craving carbohydrate and sugar rich foods was therefore a protective mechanism.

Although we are not still living in shelters or foraging for food today, food cravings in winter may still be programmed into our biology.




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3. Psychology, craving and mood

Social learning theory says people learn from each other through observing, imitating and modelling. In the context of food cravings this suggests that what our caregivers gave to us in winter as children has a striking impact on what we choose to eat in winter as adults.

A review of studies on the psychological reasons behind eating comfort food says this food may play a role in alleviating loneliness and boosting positive thoughts of childhood social interaction.

We may also naturally experience lower mood in winter and low mood has been linked to emotional eating.

In winter due to it being darker and colder, we tend to stay indoors longer and self-medicate with foods that are carbohydrate and sugar rich. These types of foods release glucose straight to our brain which gives us an instant feeling of happiness when we are feeling cold, sad, tired or bored.




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Comfort food can be healthy

For all the comfort they provide, comfort foods generally receive a bad rap because they are usually energy and calorie dense; they can be high in sugar, fat and refined carbohydrates.

These types of foods are usually linked to weight gain in winter and if you eat too much over the longer term, can increase the risk of heart disease and diabetes.

However, not all comfort foods are created equally, nor are they all bad for our health.

You still get a comforting feeling with a hearty bowl of soup, but without the extra calories.
from www.shutterstock.com

You can get the same comforting feelings from winter foods containing ingredients that are good for you. For example, a hearty bowl of soup with a slice of wholegrain bread can give you all the components you need for optimal physical and psychological health. Steaming bowls of chilli and curries can provide immunity boosting properties with the use of their warming spices. So too are all the wonderful citrus fruits that become available in the winter.

If you are craving something that is carbohydrate rich, try swapping white varieties for wholegrain versions that will dampen carbohydrate cravings. If you crave a hot chocolate try swapping the cocoa powder for cacao which has a higher concentration of vitamins and minerals.

More good news

The good news for all of us who crave comfort foods in winter is studies that assess intuitive eating — eating when you are hungry, stopping when you are full and listening to what your body is telling you to eat — suggest people who eat this way are happier with their body image, feel better psychologically and are less likely to have disordered eating.

So, embrace this wonderful chilly weather. Rug up in your favourite woolly jumper, sit by the fire, cuddle up with a loved one, make some healthier swaps to your classic comfort foods, remove the food guilt and listen to what your body is telling you it needs during these cold winter months.The Conversation

Megan Lee, Academic Tutor and PhD Candidate, Southern Cross University and Jacqui Yoxall, Senior Lecturer in Allied Health, Southern Cross University

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

Why the Australasian Health Star Rating needs major changes to make it work



Most consumers are unaware that the Health Star Rating system is compensatory, and that one negative nutritional attribute, such as high sugar, can be cancelled out by a positive attribute like fibre.
from http://www.shutterstock.com, CC BY-ND

Jessica C Lai, Victoria University of Wellington; Alana Harrison, Victoria University of Wellington; Hongzhi Gao, Victoria University of Wellington, and Samuel Becher, Victoria University of Wellington

Unhealthy diets cause multiple physical and mental health problems. To help consumers make healthier choices, Australia and New Zealand introduced the voluntary Health Star Rating (HSR) system in 2014.

The system is supposedly designed to provide consumers with an overall signal about a food’s healthiness. Presumably, this should nudge consumers to make more informed and healthier decisions.

Five years on, the Australian and New Zealand governments are conducting a system review. Our research shows that, while the initiative is noble, the devil is in the details. There is a need, and hopefully an opportunity, to improve the system and reconsider some of its key aspects.




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Loopholes and consumer misconception

Under the HSR system, products are labelled from 0.5 stars (the least healthy score) to 5 stars (the healthiest products). The rating is determined by evaluating the overall nutritional value of the product. It compares the content of “good” ingredients (i.e. fibre, protein, fruit, vegetables, nuts and legumes) with the “bad” ones (i.e. saturated fat, energy, total sugar and sodium).

But we believe most consumers are unaware that the HSR system is compensatory. This means one negative nutritional attribute can be cancelled out, or balanced, by a positive attribute. A manufacturer can receive a high HSR score for a product rich in sugar by adding a healthy ingredient such as fibre.


CC BY-ND

It is also likely that most consumers are unaware that the HSR rating is calculated on an “as prepared” basis. This means a product can enjoy a high rating based on the nutritional value of preparatory ingredients.

Milo found itself embroiled in controversy for displaying 4.5 stars on its chocolate powder, though the powder itself clearly does not merit this rating. The 4.5-star rating was based on consuming merely three teaspoons of powder combined with skim milk. But who actually consumes Milo this way?

Furthermore, HSR scores are intended to allow comparison only among similar products. A four-star rating for a cereal cannot be compared to a four-star rating given to milk. While the two products display the same number of stars, their healthiness may differ significantly.




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What holds the system back

There is scepticism about the HSR’s authenticity, reliability and effectiveness. This stems in part from the system being self-regulated.

In addition, the system is non-mandatory, leaving manufacturers free to decide when and how to use it. For instance, only around 20% of packaged goods available in New Zealand and Australian supermarkets have an HSR. To add to the distortion, a disproportionate number of these show high ratings. This indicates that manufacturers only use the HSR for their healthier products.

A voluntary system does little to counter the inbuilt incentive that manufacturers have to use unhealthy components such as sugar, salt and saturated fats. These produce pleasure and create “craveable” foods and food addiction. Manufacturers likely do not use a HSR for these products. However, consumers do not interpret missing information as “the worst-case scenario”, but assume average quality.

Finally, the system does not effectively assist the vulnerable consumers who need it the most. While HSR does help some middle- to high-income consumers, it does a poor job with respect to consumers of low socio-economic status. This suggests that the label requires consumers to be educated about its meaning.

Time to move forward

Some improvements could carry the HSR forward a great distance.

If the system were made mandatory, it would likely raise consumers’ awareness. There should also be more education initiatives about the HSR. This, in turn, would incentivise manufacturers to produce healthier foods and beverages.

At the same time, we should strive to minimise the costs involved and consider backing the system with government funding. This would allow all businesses to participate in the program, including less profitable or smaller businesses. It would also prevent costs from being passed onto consumers.

As a minimum, if the system is not made mandatory, a general “non-participation” label should be introduced. If a producer opts not to label its product, it should be required to use a conspicuous cautionary statement. Such a statement should declare, for instance, that “the manufacturer has chosen not to verify the health rating of this product” or “the healthiness of this product cannot be verified”.

Studies show the HSR rating would have a bigger impact if placed in the upper left corner of the packaging and used colours. It could use a traffic light system, with 0.5-2.5 stars on a red background, 3 to 4 stars on amber and 4.5-5 star products on green. The colour-coded system has proved to be more effective with marginalised groups of consumers.

All easier said than done.

Healthy diets are important for physical and psychological well-being and for strengthening our communities and economies. However, any regulation of the food industry is likely to be resisted by its strong and well-organised lobbying power. To fight this battle, the consumers’ voice is crucial to ensure we can all make good and healthy foods choices.The Conversation

Jessica C Lai, Senior Lecturer in Commercial Law, Victoria University of Wellington; Alana Harrison, LLB(Hons) & BCOM Undergraduate Student, Victoria University of Wellington; Hongzhi Gao, Associate professor, Victoria University of Wellington, and Samuel Becher, Associate Professor of Business Law, Victoria University of Wellington

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

Research Check: is white meat as bad for your cholesterol levels as red meat?



Whether you’re eating red meat or white meat, a lean cut is the healthier way to go.
From shutterstock.com

Clare Collins, University of Newcastle

You’ve probably heard eating too much fatty red meat is bad for your health, while lean meat and chicken are better choices. So, recent headlines claiming white meat is just as bad for your cholesterol levels as red meat might have surprised you.

The reports were triggered by a paper published in the The American Journal of Clinical Nutrition earlier this month.

The study did find lean white meat had the same effect on cholesterol levels as lean red meat. While this might be construed as good news by lovers of red meat, more research on this topic is needed for a clearer picture.

How was this study conducted?

The researchers set out to compare three diets: one where the main dietary source of protein came from eating red meat (beef and pork), another where it came from poultry (chicken and turkey), and a third where it came from plant foods (legumes, nuts, grains and soy products).

They wanted to measure the impact of these diets on specific categories of blood fats, as markers of heart disease risk. They tested blood fat markers including low density lipoprotein cholesterol (or LDL, commonly known as “bad cholesterol”), apolipoprotein B (apoB), and the ratio of total cholesterol to high density lipoprotein cholesterol (or HDL, commonly known as “good cholesterol”).




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The researchers also wanted to know whether blood fat levels changed more when the background dietary patterns were high in saturated fat, derived mostly from full-fat dairy products and butter, or when they were low in saturated fat.

To achieve this, 177 adults with blood cholesterol levels in the normal range were randomised to follow either a high-saturated fat diet (14% of total energy intake) or a low-saturated fat diet (7% of total energy intake).

Within these two groups they were further randomly assigned to follow three separate diets for four weeks each: red meat, white meat, and plant protein sources. The main protein sources in the meat groups came from lean cuts of red and white meat. In the plant diet, protein came from legumes, nuts, grains and soy products.

Participants met research staff weekly to collect their food products and received counselling on following their specified diet. Participants were asked to maintain their physical activity level and keep their weight as stable as possible so these factors did not bias the results.

To eliminate any carry-over effects from eating one type of protein to the next, participants were given between two and seven weeks break in between each diet and told to return to their usual eating patterns.




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What did the study find?

Some participants dropped out along the way, so in the end researchers had results from 113 participants.

Blood concentrations of LDL cholesterol and apoB were lower following the plant protein diet period, compared to both the red and white meat periods. This was independent of whether participants were on a background diet of high- or low-saturated fat.

There was no statistically significant difference in the blood fat levels of those eating red meat compared to those eating white meat.

We’re often told to limit our consumption of red meat.
From shutterstock.com

Eating a diet high in saturated fat led to significant increases in blood levels of LDL cholesterol, apoB, and large LDL particles compared with a background diet low in saturated fat.

So, all the dietary protein sources as well as the level of saturated fat intake had significant effects on total cholesterol, LDL cholesterol, non-HDL cholesterol, and apoB levels.

How should we interpret the results?

Although the test diets only lasted four weeks each, this study is important. It’s rare to see intervention studies that directly compare eating different types of meat and sources of protein and the impact on heart-disease risk factors. This is partly due to the challenge and expense of providing the food and getting people to follow specific diets.

Most studies to date have been cohort studies where people are categorised based on what they eat, then followed up for many years to see what happens to their health.

One review of cohort studies found no greater risk of stroke in those who eat more poultry compared to less poultry, while another showed a higher risk of stroke among those eating more red and processed meat relative to poultry intake.




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There are a few things to keep in mind with this study. First, the researchers used the leanest cuts of both red and white meats, and removed all visible fat and skin. If participants were eating fatty meat, we may have seen different results.

The significant variation in breaks between different diets (ranging from two to seven weeks) may have also affected the results. Participants with a longer break would have had more time for their blood cholesterol levels to change, compared to those with shorter breaks.

Finally, in reporting their results, it would have been better to include all 177 participants who began the study. People who drop out often have different health characteristics and leaving them out may have biased results.

This short-term study does not provide evidence that choosing lean white meat over red meat is either better or worse for your health.

But the findings are consistent with recommendations from the Heart Foundation to include a variety of plant-based foods in our diets, foods containing healthy types of fat and lower amounts of saturated fat, and in particular, to choose lean red meat and poultry. – Clare Collins


Blind peer review

The article presents a fair, balanced and accurate assessment of the study. In this study, they showed lean red meat and lean white meat (with all visible fat and skin removed) had the same effect on blood fat levels.

Importantly, plant protein sources (such as legumes, nuts, grains and soy products) lowered blood fat levels compared to the red and white meats, and this was independent of whether the participants had been placed on a background diet low or high in saturated fats. This study did not look at the impact of a fish-based diet on blood fats. – Evangeline Mantzioris




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Research Checks interrogate newly published studies and how they’re reported in the media. The analysis is undertaken by one or more academics not involved with the study, and reviewed by another, to make sure it’s accurate.The Conversation

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

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

How to get the nutrients you need without eating as much red meat



The average Australian eats 81 grams of red meat a day, while the planetary diet recommends just 14g.
Napocska/Shutterstock

Evangeline Mantzioris, University of South Australia

If you’re a red meat-eater, there’s a good chance you’re eating more of it than you should. At last count, Australians ate an average of 81 grams of red meat per day.

The planetary health diet was developed by researchers to meet the nutritional needs of people around the world, while reducing food production’s environmental impact. It recommends reducing our red meat intake to around 14g a day. That’s around 100g of red meat a week.




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Australia’s dietary guidelines are more conservative and recommend limiting red meat intake to a maximum of 455g a week, or 65g a day, to reduce the additional cancer risk that comes from eating large quantities of red meat.

So, what should you eat instead? And how can you ensure you’re getting enough protein, iron, zinc and vitamin B12?

Protein

Animal sources of protein provide essential amino acids, which the body uses to make muscle, tissue, hormones, neurotransmitters and the different cells and antibodies in our immune system.

The planetary health diet offers a good blueprint for gaining enough protein from a variety of other animal sources. It recommends eating, on average:

  • 25g of chicken per day
  • 28g of fish per day day
  • 1.5 eggs per week
  • 200g of milk per day day
  • 50g of cheese per day.

In addition to the 14g of red meat in the planetary health diet, these foods would provide a total of 45g of protein per day, which is around 80% of our daily protein needs from animal sources.

The remaining protein required (11g) is easily met with plant foods, including nuts, legumes, beans and wholegrains.

Nuts are a good alternative to meat.
Eakrat/Shutterstock

Iron

Iron is essential for many of the body’s functions, including transporting oxygen to the blood.

Iron deficiency can lead to anaemia, a condition in which you feel tired and lethargic.




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Pre-menopausal women need around 18 milligrams a day, while men only need 8mg. Pre-menopausal women need more iron because of the blood they lose during menstruation.

So, how can you get enough iron?

Beef, of course, is a rich source of iron, containing 3.3mg for every 100g.

The same amount of chicken breast contains 0.4mg, while the chicken thigh (the darker meat) contains slightly higher levels, at 0.9mg.

Pork is similarly low in iron at 0.7mg.

But kangaroo will provide you with 4.1mg of iron for every 100g. Yes, kangaroo is a red meat but it produces lower methane emissions and has one-third the levels of saturated fat than beef, making it a healthier and more environmentally friendly alternative.

Plant protein sources are also high in iron: cooked kidney beans have 1.7mg and brown lentils have 2.37mg per 100g.

Kidney beans and lentils are good sources of iron.
Hermes Rivera

If you wanted to cut your red meat intake from the 81g average to the recommended 14g per day while still getting the same amount of iron, you would need to consume the equivalent of either 50g of kangaroo, 100g of brown lentils or 150g of red kidney beans per day.

Zinc

Zinc is an essential mineral that helps the body function optimally. It affects everything from our ability to fight bugs, to our sense of smell and taste.

Zinc requirements are higher for men (14mg a day) than women (8mg a day) due to zinc’s role in the production and development of sperm.

Of all meat sources, beef provides the most zinc, at 8.2mg per 100g.

Chicken breast provides just 0.68mg, while the chicken thigh has 2mg.

In kangaroo meat, the levels of zinc are lower than beef, at 3.05mg.

The richest source of zinc is oysters (48.3mg).

Beans such lentils, red kidney beans and chickpeas all provide about 1.0mg per 100g.

To meet the shortfall of zinc from reducing your red meat intake, you could eat 12 oysters a day, which is unlikely. Or you could eat a combination of foods such as 150g of red kidney beans, one serve (30g) of zinc-supplemented cereals like Weet-bix, three slices of wholegrain bread, and a handful of mixed nuts (30g).

Vitamin B12

Vitamin B12 is important for healthy blood and nerve function. It’s the nutrient of most concern for people cutting out meat products as it’s only found in animal sources.

Requirements of vitamin B12 are the same for both women and men at 2.4 micrograms (mcg) a day.

Beef and kangaroo provide 2.5mcg per 100g serve, while chicken and turkey provide about 0.6mcg.

Dairy products also contain vitamin B12. One glass of milk would give you half your daily requirement requirement (1.24mcg) and one slice of cheese (20g) would provide one-fifth (0.4mcg).

A glass of milk would provide half the vitamin B12 you need in a day.
AntGor/Shutterstock

Vitamin B12 can be found in trace amounts in spinach and fermented foods, but these levels aren’t high enough to meet your nutritional needs. Mushrooms, however, have consistently higher levels, with shiitake mushrooms containing 5mcg per 100g.

To meet the shortfall of vitamin B12 from reducing red meat intake, you would need to eat 75g kangaroo per day or have a glass of milk (200ml) plus a slice of cheese (20g). Alternatively, a handful of dried shiitake mushrooms in your salad or stir-fry would fulfil your requirements.

Don’t forget about fibre

A recent study found fibre intakes of around 25 to 29g a day were linked to lower rates of many chronic diseases such as coronary heart disease, type 2 diabetes, stroke and bowel cancer.

Yet most Australian adults currently have low dietary fibre levels of around 20g a day.

By making some of the changes above and increasing your intake of meat alternatives such as legumes, you’ll also be boosting your levels of dietary fibre. Substituting 100g of lentils will give you an extra 5g of fibre per day.

With some forward planning, it’s easy to swap red meat for other animal products and non-meat alternatives that are healthier and more environmentally sustainable.The Conversation

Evangeline Mantzioris, Program Director of Nutrition and Food Sciences, University of South Australia

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