Why it can be hard to stop eating even when you’re full: Some foods may be designed that way



Bet you can’t eat just one.
tlindsayg/Shutterstock

Tera Fazzino, University of Kansas and Kaitlyn Rohde, University of Kansas

All foods are not created equal. Most are palatable, or tasty to eat, which is helpful because we need to eat to survive. For example, a fresh apple is palatable to most people and provides vital nutrients and calories.

But certain foods, such as pizza, potato chips and chocolate chip cookies, are almost irresistible. They’re always in demand at parties, and they’re easy to keep eating, even when we are full.

In these foods, a synergy between key ingredients can create an artificially enhanced palatability experience that is greater than any key ingredient would produce alone. Researchers call this hyperpalatability. Eaters call it delicious.

Initial studies suggest that foods with two or more key ingredients linked to palatability – specifically, sugar, salt, fat or carbohydrates – can activate brain-reward neurocircuits similarly to drugs like cocaine or opioids. They may also be able to bypass mechanisms in our bodies that make us feel full and tell us to stop eating.

Our research focuses on rewarding foods, addictive behaviors and obesity. We recently published a study with nutritional scientist Debra Sullivan that identifies three clusters of key ingredients that can make foods hyperpalatable. Using those definitions, we estimated that nearly two-thirds of foods widely consumed in the U.S. fall into at least one of those three groups.

Documentaries like “Fed Up’ (2014) have linked obesity to food industry practices and American eating habits.

Cracking the codes

Foods that are highly rewarding, easily accessible and cheap are everywhere in our society. Unsurprisingly, eating them has been associated with obesity.

Documentaries in the last 15-20 years have reported that food companies have developed formulas to make palatable foods so enticing. However, manufacturers typically guard their recipes as trade secrets, so academic scientists can’t study them.

Instead, researchers have used descriptive definitions to capture what makes some foods hyperpalatable. For example, in his 2012 book ”Your Food Is Fooling You: How Your Brain Is Hijacked by Sugar, Fat, and Salt,“ David Kessler, former Commissioner of the U.S. Food and Drug Administration (FDA), wrote:

“What are these foods? …. Some are sweetened drinks, chips, cookies, candy, and other snack foods. Then, of course, there are fast food meals – fried chicken, pizza, burgers, and fries.”

But these definitions are not standardized, so it is hard to compare results across studies. And they fail to identify the relevant ingredients. Our study sought to establish a quantitative definition of hyperpalatable foods and then use it to determine how prevalent these foods are in the U.S.

In 2018, 31% of U.S. adults aged 18 and over were obese.
CDC

Three key clusters

We conducted our work in two parts. First we carried out a literature search to identify scientific articles that used descriptive definitions of the full range of palatable foods. We entered these foods into standardized nutrition software to obtain detailed data on the nutrients they contained.

Next we used a graphing procedure to determine whether certain foods appeared to cluster together. We then used the clusters to inform our numeric definition. We found that hyperpalatable foods fell into three distinct clusters:

– Fat and sodium, with more than 25% of total calories (abbreviated as kcal) from fat and at least 0.30% sodium per gram per serving. Bacon and pizza are examples.

– Fat and simple sugars, with more than 20% kcal from fat and more than 20% kcal from simple sugars. Cake is an example.

– Carbohydrates and sodium, with over 40% kcal from carbohydrates and at least 0.20% sodium per gram per serving. Buttered popcorn is an example.

Then we applied our definition to the U.S. Department of Agriculture’s Food and Nutrient Database for Dietary Studies, or FNDDS, which catalogs foods that Americans report eating in a biennial federal survey on nutrition and health. The database contained 7,757 food items that we used in our analysis.

Over 60% of these foods met our criteria for hyperpalatability. Among them, 70% were in the fat/sodium cluster, including many meats, meat-based dishes, omelets and cheese dips. Another 25% fell into the fat/simple sugars cluster, which included sweets and desserts, but also foods such as glazed carrots and other vegetables cooked with fat and sugar.

Finally, 16% were in the carbohydrate/sodium cluster, which consisted of carbohydrate-dense meal items like pizza, plus breads, cereals and snack foods. Fewer than 10% of foods fell into multiple clusters.

Many hyperpalatable foods are widely available and cheap.
gabriel12/Shutterstock

We also looked at which of the USDA’s food categories contained the most hyperpalatable foods. Over 70% of meats, eggs and grain-based foods in the FNDDS met our criteria for hyperpalatability. We were surprised to find that 49% of foods labeled as containing “reduced,” “low”, or zero levels of sugar, fat, salt and/or calories qualified as hyperpalatable.

Finally, we considered whether our definition captured what we hypothesized it would capture. It identified more than 85% of foods labeled as fast or fried, as well as sweets and desserts. Conversely, it did not capture foods that we hypothesized were not hyperpalatable, such as raw fruits, meats or fish, or 97% of raw vegetables.

Tackling obesity

If scientific evidence supporting our proposed definition of hyperpalatable foods accumulates, and it shows that our definition is associated with overeating and obesity-related outcomes, our findings could be used in several ways.

First, the FDA could require hyperpalatable foods to be labeled – an approach that would alert consumers to what they may be eating while preserving consumer choice. The agency also could regulate or limit specific combinations of ingredients, as a way to reduce the chance of people finding foods that contain them difficult to stop eating.

Consumers also could consider the role of hyperpalatable foods in their own lives. Our team needs to do further work validating our definition before we translate it for the public, but as a first step, individuals can examine whether the foods they eat contain multiple ingredients such as fat and sodium, particularly at high levels. Recent surveys show increased interest among U.S. consumers in making informed food choices, although they often aren’t sure which sources to trust.

One starting point for people concerned about healthy eating is to consume foods that are unlikely to be hyperpalatable – items that occur naturally and have few or no additional ingredients, such as fresh fruit. As food writer Michael Pollan recommends, “Don’t eat anything your great-grandmother wouldn’t recognize as food.”

[ Get the best of The Conversation, every weekend. Sign up for our weekly newsletter. ]The Conversation

Tera Fazzino, Assistant Professor of Psychology; Associate Director of the Cofrin Logan Center for Addiction Research and Treatment, University of Kansas and Kaitlyn Rohde, Research Assistant, Cofrin Logan Center for Addiction Research and Treatment., University of Kansas

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

Should you avoid meat for good health? How to slice off the facts from the fiction



Meat is a very popular food for most Americans. Its nutritional value is a topic of much debate.
puhhha/Shutterstock.com

Dariush Mozaffarian, Tufts University

More than half of Americans who make New Year’s resolutions resolve to “eat healthier.” If you’re one, you might be confused about the role meat should play in your health.

It’s no wonder you’re confused. One group of scientists says that reducing red and processed meat is a top priority for your health and the planet’s. Another says these foods pose no problems for health. Some of your friends may say it depends, and that grass-fed beef and “nitrite-free” processed meats are fine. At the same time, plant-based meat alternatives are surging in popularity, but with uncertain health effects.

As a cardiologist and professor of nutrition, I’d like to clear up some of the confusion with five myths and five facts about meat.

First, the myths.

Red meat, while very popular, has not been shown to have health benefits.
Natalia Lisovskaya/Shutterstock.com

Myth: Red meat is good for health

Long-term observational studies of heart disease, cancers or death and controlled trials of risk factors like blood cholesterol, glucose and inflammation suggest that modest intake of unprocessed red meat is relatively neutral for health. But, no major studies suggest that eating it provides benefits.

So, while an occasional serving of steak, lamb or pork may not worsen your health, it also won’t improve it. And, too much heme iron, which gives red meat its color, may explain why red meat increases risk of Type 2 diabetes. Eating red meat often, and eating processed meat even occasionally, is also strongly linked to colorectal cancer.

Myth: You should prioritize lean meats

For decades, dietary guidance has focused on lean meats because of their lower fat, saturated fat and cholesterol contents. But these nutrients don’t have strong associations with heart attacks, cancers or other major health outcomes.

Other factors appear more important. Processed meats, such as bacon, sausage, salami and cold cuts, contain high levels of preservatives. Sodium, for example, raises blood pressure and stroke risk, while the body converts nitrites to cancer-causing nitrosamines. Lean or not, these products aren’t healthy.

Myth: Focus on a ‘plant-based’ diet

“Plant-based” has quickly, but somewhat misleadingly, become a shorthand for “healthy.” First, not all animal-based foods are bad. Poultry and eggs appear relatively neutral. Dairy may have metabolic benefits, especially for reducing body fat and Type 2 diabetes. And, seafood is linked to several health benefits.

Conversely, many of the worst foods are plant-based. Consider white rice, white bread, fries, refined breakfast cereals, cookies and so on. These foods are high in refined starch and sugar, representing 42% of all calories in the U.S., compared to about 5% of U.S. calories from unprocessed red meats, and 3% from processed meats.

Either a “plant-based” or omnivore diet is not healthy by default. It depends on what you choose to eat.

Myth: Grass-fed beef is better for your health

Conventional livestock eat a combination of forage (grass, other greens, legumes) plus hay with added corn, soy, barley or grain. “Grass-fed,” or “pasture-raised,” livestock eat primarily, but not exclusively, forage. “Grass-finished” livestock should, in theory, only eat forage. But no agency regulates industry’s use of these terms. And “free range” describes where an animal lives, not what it eats.

“Grass-fed” may sound better, but no studies have compared health effects of eating grass-fed versus conventional beef. Nutrient analyses show very modest differences between grass-fed and conventionally raised livestock. You might eat grass-fed beef for personal, environmental or philosophical reasons. But don’t expect health benefits.

Myth: Plant-based meat alternatives are healthier

Products like Impossible Burger and Beyond Meat are clearly better for the environment than conventionally raised beef, but their health effects remain uncertain. Most nutrients in plant-based alternatives are, by design, similar to meat. Using genetically engineered yeast, Impossible even adds heme iron. These products also pack a lot of salt. And, like many other ultra-processed foods, they may lead to higher calorie intake and weight gain.

So, what are the facts?

Sausages wrapped in bacon are a double whammy of unhealthy meat, as both bacon and sausage are processed meats.
MShev/Shutterstock.com

Fact: Processed meats are bad for health

Processed meats contain problematic preservatives. Even those labeled “no nitrates or nitrites added” contain nitrite-rich fermented celery powder. A current petition by the Center for Science in the Public Interest asks the FDA to ban the misleading labeling.

Besides the sodium, nitrites and heme, processed meats can contain other carcinogens, produced by charring, smoking or high-temperature frying or grilling. These compounds may not only harm the person who eats these products; they can also cross the placenta and harm a fetus.

Fact: A meatless diet is not, by itself, a healthy diet

Most diet-related diseases are caused by too few health-promoting foods like fruits, nuts, seeds, beans, vegetables, whole grains, plant oils, seafood and yogurt. Additional health problems come from too much soda and ultra-processed foods high in salt, refined starch or added sugar. Compared to these major factors, avoiding or occasionally eating unprocessed red meat, by itself, has modest health implications.

Fact: Beef production is devastating the environment

In terms of land use, water use, water pollution and greenhouse gases, unprocessed red meat production causes about five times the environmental impact of fish, dairy or poultry. This impact is about 20 times higher than that of eggs, nuts or legumes, and 45 to 75 times higher than the impact of fruits, vegetables or whole grains. A 2013 UN report concluded that livestock production creates about 15% of all global greenhouse gas emissions, with nearly half coming from beef alone.

Fact: Plant-based meats are better for the environment

Production of plant-based meat alternatives, compared to conventional beef, uses half the energy, one-tenth of the land and water, and produces 90% less greenhouse gas. But, no studies have yet compared plant-based meat alternatives to more natural, less processed options, such as mushrooms or tofu.

Fact: Many questions remain

Which preservatives or other toxins in processed meat cause the most harm? Can we eliminate them? In unprocessed red meats, what exactly increases risk of Type 2 diabetes? What innovations, like feeding cows special strains of seaweed or using regenerative grazing, can reduce the large environmental impacts of meat, even grass-fed beef? What are the health implications of grass-fed beef and plant-based meat alternatives?

Like much in science, the truth about meat is nuanced. Current evidence suggests that people shouldn’t eat unprocessed red meat more than once or twice a week. Grass-fed beef may be modestly better for the environment than traditional production, but environmental harms are still large. Data don’t support major health differences between grass fed and conventional beef.

Similarly, plant-based meat alternatives are better for the planet but not necessarily for our health. Fruits, nuts, beans, vegetables, plant oils and whole grains are still the best bet for both human and planetary health.

[ You’re smart and curious about the world. So are The Conversation’s authors and editors. You can read us daily by subscribing to our newsletter. ]The Conversation

Dariush Mozaffarian, Dean of Nutrition Science and Policy, Tufts University

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

Hoping to get in shape for summer? Ditch the fads in favour of a diet more likely to stick



The benefits of a juice cleanse or detox aren’t likely to be sustained over time.
Fron shutterstock.com

Yasmine Probst, University of Wollongong and Vivienne Guan, University of Wollongong

Weight gain can creep up on us. Over the winter months we enjoy foods that create a feeling of comfort and warmth. Many of these foods tend to be higher in calories, usually from fat or added sugars.

As we enter the summer months, some of us start to think about getting in shape – and how we’re going to look in a bathing costume.

These concerns might be met with the temptation to seek a “quick fix” to weight loss. But this sort of approach is likely to mean finding yourself back in the same position this time next year.

Looking past the quick fix and fad diets to longer-term solutions will improve your chance of keeping the weight off and staying healthy all year round.




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


Losing weight shouldn’t be a short-term solution

Extra body fat is a risk factor for developing chronic diseases including type 2 diabetes and heart disease. With two in three Australians carrying too much body fat, many of us may be well-intentioned, but not making the best choices when it comes to what we eat.

Weight loss is largely a balance of choosing the right foods and being physically active in order to tip our internal energy balance scales in the right direction.

For the most part, quick-fix diets are based on calorie restriction as a means of weight loss. They focus on different strategies to get you to eat fewer calories without having to actively think about it.

Fad diets tend to share similar characteristics, such as eating fewer varieties of foods, fasting, and replacing meals.




Read more:
Five food mistakes to avoid if you’re trying to lose weight


But weight loss isn’t just about swapping one or two foods for a month or two; it’s about establishing patterns to teach our bodies new habits that can be maintained into the future.

Fad diets and quick fix options can be limited in several respects. For example, they can be difficult to stick to, or people on them can regain weight quickly after stopping the diet. In some cases, there is insufficient research around their health effects in the longer term.

Exercise is also an important part of losing weight.
From shutterstock.com

Let’s take a look at the way some of these characteristics feature in three popular diets.

Juicing/detoxification

Juicing or detoxification diets usually last two to 21 days and require a person to attempt a juice-focused form of fasting, often in combination with vitamin or mineral supplements in place of all meals.

People on this diet lose weight rapidly because of the extremely low calorie intake. But this is a severely restricted type of diet and particularly difficult to follow long term without a risk of nutrient deficiency.

Also, while it might hold appeal as a marketing buzzword, detoxification is not a process the body needs to go though. Our livers are efficient at detoxifying with very little help.




Read more:
Trust Me, I’m An Expert: what science says about how to lose weight and whether you really need to


Intermittent fasting

An intermittent fasting diet involves a combination of fasting days and usual eating days. The fasting strategies include complete fasting (no food or drinks are consumed on fasting days) and modified fasting (20-25% of calories is consumed on fasting days).

This diet leads to weight loss due to an overall decrease in calorie intake. But it’s hard to stick with the fasting pattern as it results in intense hunger. Similarly, this diet can lead to binge eating on usual eating days.

But even though people are allowed to eat what they want on non-fasting days, research shows most do not over-eat.




Read more:
Blood type, Pioppi, gluten-free and Mediterranean – which popular diets are fads?


Overall, for people who are able to stick with intermittent fasting, we don’t have enough evidence on the benefits and harms of the diet over time.

Long term energy restriction without fasting may result in the same weight outcomes and may be a better approach to continued weight management.

The paleo diet

The palaeolithic (paleo) diet was designed to reflect the foods consumed by our Stone Age ancestors before the agricultural revolution.

The paleo diet excludes processed foods and sugars. This recommendation lines up with the current evidence-based dietary recommendations. However, the paleo diet also excludes two major food groups – grain and dairy foods.

Developing new healthier habits can take time and perseverance, but will pay off.
From shutterstock.com

While short-term weight loss might be achieved, there’s no conclusive proof of benefit for weight loss and nutritional balance in the long term. People who follow the paleo diet might be at risk of nutritional deficiencies if they’re not getting any grains or dairy.

So it’s worth taking cues from the paleo diet in terms of limiting processed foods and sugars. But if you’re thinking of adopting the diet in its entirety, it would be important to seek support from a health professional to ensure you’re not missing out on essential nutrients.

Things to look out for

So how can you tell if a diet is likely to lead to long term weight loss success? Here are some questions to ask:

  1. does it incorporate foods from across the five food groups?

  2. is it flexible and practical?

  3. can the foods be easily bought at the supermarket?

If the answer to these three questions is “yes”, you’re likely on to a good one. But if you’re getting at least one “no”, you might want to think carefully about whether the diet is the right choice for sustained weight loss.




Read more:
Four simple food choices that help you lose weight and stay healthy


Of course, seeing results from a diet also depends on your level of commitment. While it may be easier to stay committed in the shorter term, if you want to keep the weight off year round, it’s important to make checking in with your food choices part of your ongoing routine.The Conversation

Yasmine Probst, Associate professor, University of Wollongong and Vivienne Guan, Associate Research Fellow, School of Medicine, University of Wollongong

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

Cap your alcohol at 10 drinks a week: new draft guidelines



Further evidence about the harms of alcohol has accumulated over the past decade since the last guidelines were released.
Syda Productions/Shtterstock

Nicole Lee, Curtin University

New draft alcohol guidelines, released today, recommend healthy Australian women and men drink no more than ten standard drinks a week and no more than four on any one day to reduce their risk of health problems.

This is a change from the previous guidelines, released in 2009, that recommended no more than two standard drinks a day (equating to up to 14 a week).

(If you’re unsure what a standard drink looks like, use this handy reference.)

The guidelines also note that for some people – including teens and women who are pregnant or breastfeeding – not drinking is the safest option.




Read more:
Drink, drank, drunk: what happens when we drink alcohol in four short videos


What are the new recommendations based on?

The National Health and Medical Research Council looked at the latest research and did some mathematical modelling to come to these recommendations.

It found the risk of dying from an alcohol-related disease or injury is about one in 100 if you drink no more than ten standard drinks a week and no more than four on any one day.

So, for every 100 people who stay under these limits, one will die from an alcohol-related disease or injury.

This is considered an “acceptable risk”, given drinking alcohol is common and it’s unlikely people will stop drinking altogether. The draft guidelines take into account that, on average, Australian adults have a drink three times a week.

Why did the guidelines need updating?

Recent research has shown there is a clear link between drinking alcohol and a number of health conditions. These include at least seven cancers (liver, oral cavity, pharyngeal, laryngeal, oesophageal, colorectal, liver and breast cancer in women); diabetes; liver disease; brain impairment; mental health problems; and being overweight or obese.

Some previous research suggested low levels of alcohol might be good for you, but we now know these studies were flawed. Better quality studies have found alcohol does not offer health benefits.




Read more:
Health check: is moderate drinking good for me?


The new guidelines are easier to follow than the previous guidelines, which gave recommendations to reduce both short-term harms and longer-term health problems. But some people found these confusing.

Although most Australians drink within the previously recommended limits, one study found one in five adults drank more than the guidelines suggested and almost half could not correctly identify recommended limits.

The draft new guidelines are easier to follow than the old ones.
sama_ja/Shutterstock

Although women tend to be more affected by alcohol than men, at the rates of consumption recommended in the guidelines, there is little difference in long term health effects so the guidelines apply to both men and women.

The recommended limits are aimed at healthy men and women, because some people are at higher risks of problems at lower levels of consumption. These include older people, young people, those with a family history of alcohol problems, people who use other drugs at the same time (including illicit drugs and prescribed medication), and those with physical or mental health problems.

The guidelines are currently in draft form, with a public consultation running until February 24.

After that, there will be an expert review of the guidelines and the final guidelines will be released later in 2020. There may be changes to the way the information is presented but the recommended limits are unlikely to change substantially, given they’re based on very careful and detailed analysis of the evidence.

What’s the risk for people under 18?

The draft guidelines recommend children and young people under 18 years drink no alcohol, to reduce the risk of injury and other health harms.

The good news is most teenagers don’t drink alcohol. Among 12 to 17 year olds, only 20% have had a drink in the past year and 1.4% drink weekly. The number of teenagers who have never had a drink has increased significantly in the last decade, and young people are having their first drink later.




Read more:
Three ways to help your teenage kids develop a healthier relationship with alcohol


However, we know teenagers are more affected by alcohol than adults. This includes effects on their developing brain. We also know the earlier someone starts drinking, the more likely they will experience problems, including dependence.

The idea that if you give teenagers small sips of alcohol it will reduce risk of problems later has now been debunked. Teens that have been given even small amounts of alcohol early are more likely to have problems later.

What’s the risk for pregnant and breastfeeding women?

The guidelines recommend women who are pregnant, thinking about becoming pregnant or breastfeeding not drink any alcohol, for the safety of their baby.




Read more:
Health Check: what are the risks of drinking before you know you’re pregnant?


We now have a much clearer understanding of the impacts of alcohol on the developing foetus. Foetal alcohol spectrum disorder (FASD) is a direct result of foetal exposure to alcohol in the womb. Around one in 67 women who drink while pregnant will deliver a baby with foetal alcohol spectrum disorder.

Foetal alcohol spectrum disorder is characterised by a range of physical, mental, behavioural, and learning disabilities ranging from mild to severe – and is incurable.

Worried about your own or someone else’s drinking?

If you enjoy a drink, stick within these recommended maximums to limit the health risks of alcohol.

If you have trouble sticking to these limits, or you are worried about your own or someone else’s drinking, call the National Alcohol and other Drug Hotline on 1800 250 015 to talk through options or check out these resources online.




Read more:
Did you look forward to last night’s bottle of wine a bit too much? Ladies, you’re not alone


The Conversation


Nicole Lee, Professor at the National Drug Research Institute (Melbourne), Curtin University

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

Tough nuts: why peanuts trigger such powerful allergic reactions



The humble peanut. Tasty for most, treacherous for some.
Dr Dwan Price, Author provided

Dwan Price, Deakin University

Food allergens are the scourge of the modern school lunchbox. Many foods contain proteins that can set off an oversized immune reaction and one of the fiercest is the humble peanut.

Around 3% of children in Australia have a peanut allergy, and only 1 in 5 of them can expect to outgrow it. For these unlucky people, even trace amounts of peanut can trigger a fatal allergic reaction.

But what sets the peanut apart from other nuts? Why is it so good at being an allergen?

To answer this, we have to explore the pathway from allergen to allergy, and just what it is about an allergen that triggers a response from the immune system.




Read more:
What are allergies and why are we getting more of them?


How food gets to the immune system

Before coming into contact with the immune system, an allergen in food needs to overcome a series of obstacles. First it needs to pass through the food manufacturing process, and then survive the chemicals and enzymes of the human gut, as well as cross the physical barrier of the intestinal lining.

After achieving all of this, the allergen must still have the identifying features that trigger the immune system to respond.

Many food allergens successfully achieve this, some better than others. This helps us to understand why some food allergies are worse than others.

The most potent allergens – like peanuts – have many characteristics that successfully allow them to overcome these challenges, while other nuts display these traits to a lesser extent.

Strength in numbers

The first characteristic many allergenic foods have, especially peanuts, is strength in numbers. Both tree nuts and peanuts contain multiple different allergens. At last count, cashews contain three allergens, almonds have five, walnuts and hazelnuts have 11 each and peanuts are loaded with no less than 17.

Each allergen has a unique shape, so the immune system recognises each one differently. The more allergens contained in a single food, the higher the potency.
Additionally, many of these allergens also have numerous binding sites for both antibodies and specialised immune cells, further increasing their potency.

Stronger through scorching

The first hurdle for a food allergen is the food manufacturing process. Many nuts are roasted prior to consumption. For most foods, heating changes the structure of proteins in a way that destroys the parts that trigger an immune response. This makes them far less potent as allergens.

This is not the case for many tree nuts: allergens in almonds, cashews and hazelnuts survived roasting with no loss of potency.

And for the major peanut allergens, it’s even worse. Roasting actually makes them more potent.




Read more:
Can I prevent food allergies in my kids?


The gauntlet of the gut

From here, the allergen will have to survive destruction by both stomach acid and digestive enzymes within the human gut. Many nut allergens have the ability to evade digestion to some degree.

Some simply have a robust structure, but peanut allergens actively inhibit some of the digestive enzymes of the gut. This helps them safely reach the small intestine, where the allergens then need to cross the gut lining to have contact with the immune system.

This is where peanut allergens really stand apart from most other allergens. They have the ability to cross the intestinal cells that make up the gut lining. Given their relative sizes, this is like a bus squeezing itself through a cat flap.

Peanut allergens accomplish this remarkable feat by altering the bonds that hold the gut cells together. They can also cross the lining by hijacking the gut’s own ability to move substances. Once across, the allergens will gain access to the immune system, and from there an allergic response is triggered.

Peanut allergens attack the bonds that hold intestinal cells together.
Dr Dwan Price, Author provided

The combination of multiple allergens, numerous immune binding sites, heat stability, digestion stability, enzyme blocking, and the effect on the gut lining makes peanut a truly nasty nut.

Where to from here?

This leaves us with a nagging question: if peanuts are so potent, why doesn’t everyone develop a peanut allergy? We still don’t know.

Recently, a potential vaccine developed by researchers from the University of South Australia has shown promise in reprogramming the immune system of mice and blood taken from people with peanut allergy. Will this translate to a potential treatment for peanut allergy? We will have to wait and see.

For now, the more we learn about the action of allergens, and the more we understand their effects on our body, the more we can develop new ways to stop them. And eventually, we might outsmart these clever nuts for good.The Conversation

Dwan Price, Molecular Biologist and Postdoc @ Deakin AIRwatch pollen monitoring system., Deakin University

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

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.




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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.




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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?




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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



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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.




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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.