Magical dietary fibres

hamburger_(Tony_Evans)

Dietary fibre can influence appetite (Photo: Tony Evans).

We have all heard the “eat more fibre” mantra and wondered what this is all about. So did scientists. Sure we have long known it is good for gut health and function. Recently with the exploration of the gut microbes – the microbiota – we have learnt that dietary fibre can support survival and growth of the good bugs. That we have written about before.

Now scientists have found another piece of the puzzle. Some of the fermentation products produced by the gut microbes from the dietary fibre that our own enzymes cannot digest have the potential to influence our appetite. That is incredible and provides a further insight into the obesity conundrum.

The new mechanism

Obesity is currently one of the most serious global threats to human health. Susceptibility to obesity is determined by genetic background, diet, and lifestyle. Now it has become apparent that the resident intestinal microbes in the large intestine also play an important role.  During the process of microbial fermentation of non-digestible fibre, the short-chain fatty acids acetate, propionate and butyrate are formed.

While short-chain fatty acids can serve as an energy source, the scientists showed that they also act as signaling molecules for the free fatty acid receptor 2 (FFAR2) found in enteroendocrine L cells in the large intestine. These specialised gut cells secrete the appetite suppressing hormone peptide YY (PYY). FFAR2 signaling was found to drive an expansion of the PYY cell population within the large intestine, leading to increased circulating PYY. This is associated with a reduction in food intake and protection against diet-induced obesity.

Evidence points to the production of short-chain fatty acids by the gut microbiota as an important appetite regulatory signal.

So what are fibres?

almonds

Almonds are good sources of dietary fibre.

Just to be clear, dietary fibre is the indigestible portion of food derived from plants. Chemically, dietary fibre consists of non-starch polysaccharides such as arabinoxylans, cellulose, and many other plant components such as resistant starch, resistant dextrins, inulin, lignin, chitins, pectins, beta-glucans, and oligosaccharides. Food sources of dietary fibre are often divided according to whether they provide predominantly soluble or insoluble fibre.

Soluble fibre is found in varying quantities in all plant foods, including in a range of legumes, in oats, rye, chia, and barley, in several fruits, in vegetables, in root tubers and in nuts, with almonds being the highest in dietary fibre.

Sources of insoluble fiber include whole grain foods, wheat and corn bran, legumes such as beans and peas, nuts and seeds and vegetables such as green beans, cauliflower, zucchini and celery.

So there you have a wide variety of healthy foods with the potential of reducing your hunger pangs and alleviate the risk of overweight and obesity.

Rosemary benefits – believe it if you must

diet_(Christina_Roervik

Benefits of a balanced diet.

I might be a bit repetitive here, but allow me to be clear at the beginning of this blog. There are no magic individual foods.

Sure there are good and bad foods that might tilt your habitual diet towards being more beneficial or detrimental to health. But it is the overall balance that is most important for a healthy life.

With that caveat in mind, we are going to look at purported health effects of rosemary, a perennial woody herb.

The ageing population of Acciaroli

There’s a little village in Italy called Acciaroli that has been doing the rounds in the international press during 2016. The reason: an unusual number of the small southern Italian township’s population is over the age of 100. And they have the micro-circulation of significantly younger people. These are the small blood vessels that send nutrients to the brain and organs and pull out metabolic waste products, but which tend to deteriorate with age.

Could it be something about the air, the ocean, the mountains, the hills, the olive and berry trees?

Or maybe the food. Scientists found that at every meal they’re eating anchovies, and they eat them fried and greasy. Typically, that will be washed down with a glass or two of wine. Greasy anchovies and wine – maybe a little far fetched for supporting a long life.

What about rosemary? Well, research recently released showed the almost daily consumption of rosemary by the Acciaroli population – infused in the local olive oil, cooked in pasta dishes and chewed raw. And this habit has been linked to improved micro-circulation and a concomitant effect on longevity.

The benefits of rosemary

rosemary

Potential health impact of rosemary consumption.

The first benefit – rosemary tastes great. Italian cooking uses rosemary in abundance. It’s an easy and reliable herb to grow. A light prune once a year will keep the rosemary bush in shape. One plant will provide more than enough for regular use. It works in both savoury and sweet meals. Rosemary, along with roughly chopped garlic, onion, carrots and celery sautéed in olive oil and cooked, forms ‘soffrito’ – the basis for many different stocks, soups, sauces and other dishes.  It can also be used in desserts, like a panna cotta, with some grappa.

The second benefit – rosemary contains a number of phytochemicals, including rosmarinic acid, camphor, caffeic acid, ursolic acid, betulinic acid, and the antioxidants carnosic acid and carnosol. A lot to take in, but let’s focus on rosmarinic acid. Research has shown that it has a number of interesting biological activities, e.g. antiviral, antibacterial, antiinflammatory and antioxidant. The presence of rosmarinic acid in medicinal plants, herbs and spices has beneficial and health promoting effects. In plants, rosmarinic acid is supposed to act as a preformed constitutively accumulated defence compound. If you don’t like rosemary, rosmarinic acid can also be found in many other culinary herbs such as basil, lemon balm, marjoram, sage, thyme and peppermint.

The third benefit – it is also a good source of iron, calcium, and vitamin B6. Although as a herb it is consumed in such small amounts that this might not be important enough to influence health.

No harm done

Convinced yet? Maybe not and the researchers also kept an open mind. Further studies are underway to further explore the findings. But in the meantime there’s certainly no harm in increasing your consumption and use of rosemary or related herbs.

A bathtub of sugary soft drinks

bathtub

Consumption of sugar sweetened beverages equal a bathtub worth per year.

Can you believe it, when analysing data collected through the UK National Diet and Nutrition Survey, Cancer Research UK found that teenagers aged between 11 and 18 drink almost a bathtub full of sugary drinks on average in a year. To be more precise the average soft drink consumption for this group equalled 77L per year. That is actually a very small bathtub as they normally vary in size from 77L to say 170L. However, when taking a bath the water volume is most often just half that so drinking a bathtub of soft drinks per year is a fairly accurate estimate.

The figures shed light on the extreme sugar consumption of UK teenagers in that they eat and drink three times the recommended limit, with sugary drinks being their main source of added sugar. This contributes to the development of overweight and obesity and obese children are around five times more likely to grow into obese adults. The situation is similar in many other countries. Sales of sugar sweetened beverages in Australia equates to 75L per year for every adult and child, while overall consumption of sugar sweetened beverages per person in the USA has been estimated at 115L per year.

And on it goes. So what can be done?

Taxing sugar in soft drinks

In an effort to reduce the detrimental effects of consuming excessive volumes of sugary drinks, a tax has been suggested similar to the tax on tobacco. Several countries have already imposed a tax while others are in the process to do so.

Norway has had a generalised sugar tax on refined sugar products, including soft drinks, in more than 35 years. Hungary’s tax introduced in 2011 has seen 22% of people reduce energy drink consumption and 19% of people reduce their intake of sugary-sweetened soft drinks. France introduced a targeted tax on sugary drinks at a national level in 2012 and found that sales of soft drinks declined in the year following the introduction of the tax, following several years of annual growth. Annual sales of soft drinks in Mexico declined 6% in 2014 after the introduction of a tax in 2013.

South Africa, Ireland and the United Kingdom have all decided to introduce soft drink taxes in 2017-2018. The United States does not have a nation-wide soft drink tax, but a number of cities have or will soon introduce their own taxes. There has been a growing debate around taxing soft drinks in various cities, states and even in congress in recent years. This debate alone has raised awareness of the problem and soft drink consumption is on the way down.

Other countries are still debating the benefits of a sugar tax. In Australia there is an expert group proposal to introduce a tax of 40 cents per 100 grams of sugar, which would lift the price of a two-litre bottle of soft drink by about 80 cents.

What about diet beverages?

dietsodadrinker

Diet beverages might not be the solution to reduce the incidence of obesity.

The reduction in the consumption of sugar sweetened beverages is all good if it is replaced by water. But what about diet beverages? Sugar substitutes like aspartame are supposed to promote weight loss, but a number of clinical and epidemiologic studies have suggested that these products don’t work very well and may actually make things worse. This is quite confusing as energy intake is reduced. However, there has been some evidence that artificial sweeteners actually can make you more hungry and thus may be associated with increased energy consumption.

Now a research team has found a possible mechanism explaining why use of the sugar substitute aspartame might not promote weight loss. Their report show how the aspartame breakdown product phenylalanine blocks a gut enzyme called intestinal alkaline phosphatase (IAP). And IAP is normally protective in that it has been shown to prevent obesity, diabetes and metabolic syndrome.

The researchers also showed that mice receiving aspartame in their drinking water gained more weight, had higher blood sugar levels, which indicates glucose intolerance, and higher levels of the inflammatory protein TNF-alpha in their blood, which suggests the kind of systemic inflammation associated with metabolic syndrome.

So what to do?

It is quite clear that just a debate around the detrimental effects of excessive consumption of sugar sweetened beverages can have an effect. Add to that an increase in the price and the benefits are obvious as shown already in several countries.

But it is equally important that the new choice of beverage doesn’t add to the problem. The use of artificial sweeteners might not be as innocent as could be expected.

Known impossibles

There are a number of known knowns say food safety types and they insist that we follow their sometimes impracticable or impossible advice. But is scientific opinion always right?

Impossible hand washing advice

handwash_(Marmotto)

The ever important hand wash (Photo: Marmotto)

They want us to wash our hands for an impossible 20 seconds. It doesn’t sound much but you stand there with cold hands since it might take more than 20 seconds for the warm water to flow through the long pipe.

Well, Health Canada is a little more sensible reducing the washing time to 15 seconds but insisting it should be warm water. However, contrary to popular belief scientific studies have shown that using warm instead of cold water has no effect on reducing the microbial load on hands. Scientific results also show that soap is more effective than water only and drying with a paper towel is preferable to using hand driers for removing the bugs on your hands.

So the practical recommendation? Above all wash your hands before preparing food with a method you feel comfortable with.

Impossible fruit and vegetable advice

They want us to eat 2 portions of fruits and 5-6 portions of vegetables per day. Translated to weight that would be 300 grams of fruit and 450 grams of vegetables or a full 750 grams in total on a daily basis. Are they mad, there will be no place for anything else.

However, to be fair a meta study showed that a diet with more than five servings of fruit and vegetables reduces a person’s risk of developing conditions such as heart disease and diabetes. But according to the Australian Bureau of Statistics, in 2014-15, while half of Australians aged 18 years and over met the guidelines for recommended daily serves of fruit (2 or more serves), only 7% met the guidelines for serves of vegetables (5-6 or more serves). A paltry one in twenty adults met both guidelines.

See what I am saying? And the situation is similar in many other countries. So the practical recommendation? Sure, try to increase your consumption of fruit and vegetables. An extra leaf of lettuce and a tomato on your lunch sandwich might help.

Impossible rule change for dropped food

chocolate_cake

A dropped slice of chocolate cake might be rescued.

And now we cannot follow the 5-second rule any longer, that is if you drop a piece of food on the floor but pick it up within 5 seconds you are safe to still eat it. What a waste of food. Just imagine you drop a nice slice of chocolate cake on the floor but pick it up immediately before the dog can take it and you still have to throw it away. No way I would say and by the way chocolate is dangerous for dogs so you have to be quick anyway.

Though scientists have backed up the new advice. They experimented with different food and contact surface types and concluded that the 5-second rule is a significant oversimplification of what actually happens when bacteria transfer from a surface to food. Bacteria can actually contaminate the food instantaneously. The scientists demonstrated that the 5-second rule was relevant in the sense that longer contact time resulted in more bacterial transfer, but factors like the nature of the food and the surface it falls on are of equal or greater importance.

And the practical recommendation? Obviously it doesn’t help to be quick, the bugs will still beat you. But you might wash off a hard surface and scrape off a little bit of the chocolate cake before eating the rest. If the food is still to be heated there is no problem. But a buttered sandwich surface down might be best to put in the garbage bin.

Impossible fiddling with temperature probes

They also say that when you prepare your hamburgers you cannot rely on your visual senses anymore. That is colour, firmness and smell are not considered sufficient. You have to use a digital thermometer and make sure that the centre of the hamburger reaches 71ºC. You have to fiddle with the thermometer tip sticking it into the side of the burger to reach all the way to the middle while at the same time avoiding getting your fingers burnt. And you have to do it for each burger separately.

Scientists explain that heat-induced denaturation of myoglobin, responsible for the characteristic dull-brown colour of cooked meats, is influenced by a multitude of factors. The interactions between these factors critically influence the internal cooked colour and can confuse the consumers who often wrongly perceive cooked colour to be a reliable indicator for doneness and safety. But there are some hope. Another scientific study agreed that colour alone was a misleading guide for the core temperature of a hamburger. However, when including texture of the meat and clarity of the meat juice in the judgement the situation improved.

And the practical recommendation? It might pay off to invest in a meat thermometer but once familiar with the cooking time needed to reach the recommended core temperature a bit more flexibility might be possible. As long as you promise to not eat rare or medium-rare hamburgers.

Impossible cross-contamination prevention

cutting-board

Use different cutting boards to avoid cross-contamination. 

And there’s more. You are not allowed to keep the same cutting board and utensils you just used to cut your raw chicken for subsequently preparing your vegetables to eat without further heating. Come on, the food will be cold before you have done all the washing up.

Well, I am sorry to say that scientists are unequivocal on this point. You just have to use different utensils for raw and cooked meat and utensils that have been in contact with raw meat can never be used for produce that will be consumed without further heating.

Known unknowns and unknown unknowns

For all the food safety rules for known knowns, there is little said for the known unknowns that we might worry more about.

What about the bisphenol A in our food packaging material and cash register receipts? There have been several reports of damaging endocrine effects on unborn babies, but this science is still controversial so you’re on your own on this one.

And of course nothing can be said about unknown unknowns.

Acrylamide, a carcinogen, has been present in some heated foods since time memorial following the invention of fire. But it was not until the late 20th century that it was detected by a coincidence. Since then there have been many attempts to reduce its presence in food.

What else is lurking around? That is impossible to say so better relax. Overall, a balanced diet is the best protection for a healthy life. Stay sufficiently safe to stay healthy might be the best motto!

More dietary fibre

microbiomeniaid

Beneficial bugs (Photo: NIAID)

Be kind to your intestinal flora and it will be kind to you in return. We are talking about the microbiome, the trillions of bugs in your large intestine living in symbiosis with you.

We have written about the microbiome before. All the good deeds the bugs can do if you just feed them the right raw material. And dietary fibre is the ideal food source to support the needs of the beneficial bugs.

The fibre gap

Insufficient nutrients for our gut bacteria have been linked to a loss of certain beneficial bacterial species in western societies and are likely impacting our immunological and metabolic health. Most westerners consume only half of the amount of dietary fibre recommended by dietary guidelines. Nutritionists refer to this as the “fibre gap,” and it is a problem because dietary fibre is the primary source of nutrition accessible to gut bacteria in humans.

Scientists have long promoted the importance of strategically increasing dietary fibre intake as one path forward in regaining gut microbial biodiversity. Although this advice is far from new, the now proven depletion of the microbiome with a fibre deficient diet adds a new perspective to the western diet that we are currently eating.

Comparative studies between rural communities from Africa and South America and industrialised western communities from Europe and North America have revealed specific adaptations of their microbiomes to their respective lifestyles. These adaptations include higher biodiversity and enrichment of Bacteroidetes and Actinobacteria in rural communities, and an overall reduction in microbial diversity and stability in western populations.

Restoring fibre intake can have immediate effects

Some scientists are concerned that a dramatic shift away from a diet similar to the one under which the human-microbiome symbiosis evolved is a key factor in the rise of non-communicable disorders like obesity. There is also a lot of epidemiological evidence that food products containing dietary fibre can help prevent the development of colon cancer and reduce the incidence of coronary heart disease.

It is clear that people living in non-industrialised societies have an average intake of fibre that is much higher than the low norms of western societies. In an experiment scientists compared the effects of a traditional South-African and a modern American diet.  Twenty South Africans gave up their corn porridge and vegetable stews for burgers and fries. And 20 Pittsburghians sacrificed fast food staples for the low-fat, high-fiber fare that South Africans traditionally eat that contained 55 grams of daily dietary fibre. Surprisingly, the Americans had improved markers for colon cancer already within two weeks, while the South Africans showed the opposite effects.

The good news is the finding that changes in the microbiome are largely reversible within a single generation if the fibre intake is increased. However, there are also bad news. With several generations on a fibre deficient diet a progressive loss of diversity is seen, which is not recoverable. So your children and children’s children will lack some of the beneficial microbial species, indicating that extinctions can occur in only a few generations.

Convinced yet?

Veggies

Eat more fibre-rich food

It is recommended to eat 25-30 grams of dietary fibres a day from a variety of foods rich in both insoluble and soluble fibre.

Foods higher in insoluble fibre include:

  • whole grain breads and cereals
  • the outer skins of fruit and vegetables
  • nuts and seeds
  • raw lentil, kidney beans and chickpeas

Foods higher in soluble fibre include:

  • fruits and vegetables
  • dried beans and lentils
  • oats

To help meet your daily dietary fibre requirements look at the below table from the Dietitians Association of Australia:

Food Fibre content
3/4 cup whole grain breakfast  cereal  4.5g
2 slices wholemeal bread 4.5g
1 apple (with skin) and 1 orange  5.5g
2 cups mixed raw vegetables 10g
1/4 cup legumes eg. baked beans 3g
Total 27.5g

Smoke might not be so hot

fire2

The good news about smoke and fire

We have previously mentioned the potential harmful effects of smoke-induced compounds formed during barbecuing or smoking of food. Now new findings point to a developmental edge for humans.

A genetic mutation may have helped modern humans adapt to smoke exposure from fires. This might have produced an evolutionary advantage over competitors like Neanderthals as modern humans are the only primates that carry this genetic mutation.

No fire without smoke

There is evidence that both humans and Neanderthals used fire. Our ancestors were likely using fire at least a million years ago, and maybe even two million years ago. Fire would have played an important role for cooking, protection and heating. Cooking with fire allowed our ancestors to incorporate a broader range of foods in the diets by softening roots and tubers and help increase the digestibility of other foods. Fire also provided warmth, and has long been used for landscape burning and as part of hunting and gathering.

But no fire without smoke (or is it the opposite?). And smoke-derived toxins like dioxins and polycyclic aromatic hydrocarbons can lead to respiratory infections and, for expectant mothers, exposure to these toxins can increase the chance of low birth weight and infant mortality. Even worse, they can increase the risk of cancer and lead to cell death at high concentrations.

Increased tolerance to smoke-induced toxins

Human_Evolution

Exclusive mutation that protects humans (Illustration: MagneticHyena)

The mutation may have offered ancient humans a potentially increased tolerance to toxic materials produced by fires. Although you want your body to be able to detoxify the compounds, doing it too rapidly might overload the system and cause cell death. It is all about differences in the aryl hydrocarbon receptor that regulates the body’s response to smoke-derived toxins. The mutation in the receptor is located in the middle of the ligand-binding domain and is found in all present-day humans. Ligands are small molecules that attach to receptor proteins in certain areas in much the same way that keys fit into locks.

By inhaling smoke and eating charcoal-broiled meat Neanderthals were exposed to large amounts of smoke-derived toxins they metabolised too quickly, while humans would exhibit decreased toxicity because they metabolised these compounds more slowly. Thus, our tolerance allowed us to pick up other bad habits like smoking cigarettes.

But remember that the mutation is not giving us a free-out-of-jail card. Although we are at a great advantage compared to Neanderthals, having the mutation made a hundred-fold to as much as a thousand-fold difference, there is still quite a considerable risk remaining. So go easy with the barbecuing and don’t adopt the bad smoking habit.

A teaspoon of horseradish

Horseradish

Horseradish another superfood if you believe there are such foods.

Here we go again, another superfood. This time with cancer fighting properties. And the scientists say that a teaspoon is enough to achieve the beneficial effects. So what’s not to like?

Well, the pungent aroma and the bitter taste of the food in the first place. We are talking about glucosinolates found in a range of cruciferous vegetables, but in horseradish in particular.

And when the glucosinolates are activated some of the resulting compounds have proven to be protective against cancer. And that we like.

A bit of background

Glucosinolates are natural components of many pungent plants such as mustard, broccoli, cabbage, and yes horseradish. About 132 different glucosinolates are known to occur naturally in plants. As is common, these natural chemicals contribute to a plant’s defence against pests and diseases.

The pungent taste of those plants is due to mustard oils produced from glucosinolates when the plant material is chewed, cut, or otherwise damaged. The plants contain the enzyme myrosinase that is released during chewing and transforms the glucosinolate into mainly isothiocyanate (mustard oil), the active form. The myrosinase and glucosinolates are stored in separate compartments of the plant cells so not to damage the plant itself until chewed.

Glucosinolate type and quantity vary depending on the plant variety, although closely related taxonomic groups typically contain only a small number of the different compounds. Many reviews have addressed the occurrence of some glucosinolates in vegetables with a major focus on negative aspects, like antinutritional or goitrogenic effects. However, there is a positive side now getting increased attention represented by beneficial health properties of some other glucosinolates.

So what are the health benefits?

The metabolic activation of glucosinolates results in the formation of isothiocyanates that in turn have been found to inhibit the development of cancer in several organs in rats and mice, including the bladder, breast, colon, liver, lung, and stomach. Also human epidemiological studies suggest that isothiocyanates are protective against cancers of the lungs and alimentary tract. Studies in animals and experiments with cells grown in the laboratory have identified several potential ways in which these compounds may help prevent cancer by:

  • protecting cells from DNA damage
  • inactivating carcinogens
  • having antiviral and antibacterial effects
  • having anti-inflammatory effects
  • inducing cell death (apoptosis)
  • inhibiting tumor blood vessel formation and tumor metastases.

And now a research team has studied the effects of the glucosinolates present in horseradish. The researchers found different concentrations of allyl isothiocyanate (AITC) and  1-cyano 2,3-epithiopropane (CETP) depending on the horseradish variety. And AITC is the one you want. The team suggests that AITC is a good dietary anti-carcinogen, not only because it activates the enzyme responsible for detoxifying cancer-causing molecules, but also because a large proportion of it, 90%, is absorbed when ingested.

Getting sufficient protection

horseradish-prepared

A teaspoon of horseradish is beneficial to health.

Eating 3–4 portions of broccoli per week has previously been shown to provide a protective effects against certain cancers.

And now the researchers showed that horseradish contains approximately 10 times more glucosinolates than its superfood cousin, broccoli.

So your choice. You can eat 3-4 teaspoons of horseradish a week if you can stomach it, or you can replace each teaspoon by a portion of broccoli if that is more appetising. Or a range of other cruciferous vegetables.

Scientific knowledge vs. consumer experience

Disparate views between
scientists and consumers
(Drawing: Robin Hutton)

Scientists have long recommended that we eat at least 400g of fruit and vegetables a day with some countries going even further. Australia recommends a daily intake of two fruit and five vegetable portions equivalent to 750g. But the experience of consumers is that this is almost impossible and anyway could be quite expensive depending on seasonality and regional availability.

Many scientists believe that genetically modified agricultural commodities will solve future food shortages following an increasing world population and harsher growing conditions due to global warming. The public is sceptical having experienced previous backlashes. Monocultures are expected to threaten species versatility and superweeds to overwhelm production systems.

Scientists warn about an ‘obesity epidemic’ that will overwhelm the future hospital system and issue nutrition recommendations. The general public experiences an increasingly busy lifestyle with work pressure inundating leisure time. There is little time for food preparation and a living environment conducive of exercise is missing.

What to do?

These are some of the topics discussed in a just released rather unique book that combine the views of sociological and public health expertise to provide a holistic discussion of food safety issues.

The book offers a comprehensive understanding of the current scientific knowledge concerning risks associated with food production, processing and consumption, with particular attention to the gap between scientific research and public perception.

The book is thematically arranged according to the application of theoretical approaches in sociological theory – the socio-cultural perspective, the risk society perspective and the governmentality perspective – each chapter focuses on a particular area of interest or concern in relation to food, for example:

  • the ‘obesity epidemic’,
  • the benefits or otherwise of dietary supplements,
  • caffeine consumption,
  • GM food,
  • alcohol,
  • organic food,
  • the consumption of fruit and vegetables, and
  • pathogens and contaminants.

The existing literature is covered in detail and the book offers illustrative empirical examples, whilst identifying gaps in knowledge and areas for further research.

Interested?

The book is available now from Routledge:

Risk book

 

 

 

 

 

 

Food and the Risk Society
The Power of Risk Perception
By Charlotte Fabiansson, Stefan Fabiansson

ISBN 978-1-472-47896-2
© 2016 – Routledge

282 pages

Eating in moderation

Pizza size is all in the eye of the beholder (Photo: Valerio Capello).

Pizza size is all in the eye of the beholder (Photo: Valerio Capello).

In 1978, I visited the USA with two colleagues on a mission to study meat quality. After travelling by car for many hours to reach Texas we got very hungry and stopped at a pizza joint in Oklahoma. We had a choice of small, medium, large and very large pizzas. We settled on one medium each as one should eat in moderation, but huge pizzas each covering half of the table arrived. We couldn’t even eat half of the pizzas.

This highlights that there is no universal measure of eating in moderation.

What is moderation?

Eating in moderation seems to be practical advice for a healthy diet, but a new study suggests that it is an ineffective guide for losing or maintaining weight. The scientists found that the more people liked a food, the more flexible their definitions of moderation were. And who doesn’t like pizza?

Of course moderation is a relative term that doesn’t allow a clear, concise way to guide behaviour as people think of moderation through their own objective lens. They tend to exaggerate what moderation is based on individual perceptions. Frugal Scandinavians might see a five-slice pizza as a satisfying amount, while more generous Americans might desire a ten-slice pizza.

The scientists concluded that people do think of moderation as less than overeating, so it does suggest less consumption. But unfortunately they do think of it as more than what they should eat. So moderation is more forgiving of their desires. The study adds to the growing body of knowledge that suggests people are poor judges of the amounts of food they eat.

In a general backlash against dieting there are now entire healthy eating movements oriented toward the idea of moderation. But those movements assume people can actually be good judges of what they’re eating and what constitutes an appropriate amount, which they obviously are not.

So what to do?

Go for a smaller plate to reduce food intake.

Go for a smaller plate to reduce food intake and still be happy.

A recent Cochrane review of 69 food consumption intervention studies, published between 1978 and 2013, found that people consistently consumed more food and drink when offered larger-sized portions, packages or tableware than when offered smaller-sized versions. This is a little confusing and the researchers stated that the mechanisms underlying the “portion size effect” are not fully understood.

However, people generally perceive the amount served to them as representing an appropriate portion size and consume less when offered smaller portions and more when offered larger portions. The way in which food and drink is presented can also influence consumption. The size and shape of a plate or glass can alter perceptions of quantity and influence how much is consumed.

I repeat, the size of your plate seems to be important in how much you eat. And the size of your glass may influence how much you drink.

In support of this theory another study proved that a larger glass of wine — not the amount in the glass, but the size of the glass itself — might make you drink more. Researchers tracked purchases in a bar over 16 weeks, during which time different sizes of wine glasses were used, small (250 mL), standard (300 mL) or large (370 mL), while the serving of wine was kept at 175 mL. With larger glasses there was an almost 10% increase in wine consumption. It may be that larger glasses change our perceptions of the amount of wine, leading us to drink faster and order more.

Go for smaller tableware

Although it seems natural to eat less with reductions in the portion size presented, it is very interesting to notice the influence of the size of glasses and plates. The solution to overindulgence might be to reduce the size of your tableware. That could be quite helpful and easy to fix at home.

New bad findings for bisphenol A

Canned food

Bisphenol A can be found in many canned food products.

We have covered bisphenol A, called BPA for short, several times before. In case you need to be reminded, it is a chemical widely used in plastic water bottles, metal food cans, and receipt paper. A large number of scientific publications have questioned the safety of BPA. High doses were found to influence the hormonal balance by acting as an endocrine disruptor with oestrogenic effects already in the 1930’s.

Debate over the toxicity of BPA is on-going with findings of potential low-dose effects particularly worrying. The European Food Safety Authority (EFSA) has so far refrained from suggesting that BPA should be banned, contrary to the opinion of government scientists from France and Denmark. At least EFSA lowered the temporary tolerable daily intake (tTDI) by more than 10 times in its latest opinion. And BPA has been removed from baby bottles in many countries.

New bad reports piling up

By setting a temporary TDI, EFSA committed to the re-evaluation of BPA when a two-year study by the U.S. National Toxicology Program becomes available in 2017. But in the meantime results from several other studies have been published.

A report by the Dutch National Institute for Public Health and the Environment (RIVM), critically examined two studies describing pre- and perinatal effects of BPA on the immune system. The report recommended supporting research on alternatives to BPA and advising consumers to reduce their exposure to BPA from food and other sources.

Third

Foetal exposure to BPA promotes obesity later in life for girls.

And another recent study equally points to the often neglected prenatal exposure to BPA. A team of U.S. researchers tracked 369 mother-child pairs from the third trimester of pregnancy until the children turned seven years old. They measured BPA levels in the mothers’ urine during pregnancy and then checked the children’s height, weight, waist circumference, and body fat as they aged, also measuring their BPA levels. They adjusted the results for factors that could potentially skew the results, including race and pre-pregnancy obesity among the mothers.

They found that the higher the mothers’ BPA exposure was during pregnancy, the more signs of obesity girls showed at age seven. There was no such association for boys; nor was there any relation between BPA levels in the children’s urine and obesity as they grew.

So it seems that the foetal period is when we’re most vulnerable to BPA and its ability to alter metabolism and the way our bodies generate fat cells. It is not surprising that BPA seems to affect girls differently than boys since as an endocrine-disrupting chemical it mimics or blocks hormones produced by the body. Boys and girls produce different hormones, so hormone-disrupting chemicals might be expected to affect them differently.

And if that’s not enough, experimental laboratory evidence suggests that BPA is a neurodevelopmental toxicant. In further disturbing findings, a longitudinal cohort study confirmed the association between prenatal BPA exposure and child behaviour in preschool-age children, accounting for postnatal BPA and other potential confounders. Among boys, prenatal BPA exposure was positively associated with higher scores on all syndromes and significantly associated with Emotionally Reactive and Aggressive Behaviour. Inverse associations were seen in girls for all syndromes and these associations were significant for Anxious/Depressed and Aggressive Behaviour.

How long to wait?

Protect your child from becoming obese.

Take your own action to protect your child from becoming obese.

So it seems pretty clear that BPA can have significant effects at levels of exposure seen in real life.

Do we really have to wait further for some real progress. Authorities seem reluctant to take decisive action despite overwhelming proof of harmful effects. Sure, not all findings point in the same direction and alternatives to BPA might be as bad.

But don’t despair, you can take your own action. To reduce exposure to BPA, the National Institute of Environmental Health Sciences recommends avoiding plastic containers numbers 3 and 7, shifting from canned foods to fresh or frozen foods, and, when possible, choosing glass, porcelain, or stainless steel containers, especially for hot food and liquids.

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