Global warming and arsenic in rice

In a series of posts we are going to look at the impact of global warming on food production and the potential for an increase in toxic compounds in our normal diet. First off is rice and higher levels of arsenic found in the rice grain when exposed to higher temperatures during cultivation.

Rice is the world’s most important foodstuff providing nutrients and energy to more than one half of the world’s population. Unfortunately, rice can also contain arsenic, which can cause multiple health conditions and diet-related cancers. In an earlier post we described possible chronic health effects of natural levels of arsenic in food and water.

Here we will cover two issues – the influence of higher global temperatures on arsenic levels in rice and types of arsenic compounds formed in soil under different environmental conditions.

Temperature dependence of arsenic accumulation

Arsenic occurs naturally in soil at different levels across the world. When farmers grow crops like rice under flooded conditions, arsenic is drawn out of the soil and into the water. As rice plants extract water through their roots to its leaves, arsenic follows as it mimics other molecules that rice plants preferentially draw out of the soil.

Now researchers at the University of Washington have found that warmer temperatures, at levels expected under most climate change projections, can lead to higher concentrations of arsenic in rice grains at ranges where they begin to have further health concerns. Arsenic concentrations in the grain more than tripled between the low- and high-temperature treatments.

However, the researchers didn’t have the means to check the type of arsenic compounds found.

Some forms of arsenic are more toxic than others.

It is important to know that not all arsenic is the same as arsenic exists in several different forms. Fish and seafood usually contain high levels of arsenic, but most of this is arsenobetaine, an organic form with little toxicity. It is the inorganic arsenic that can be found in water and rice and a range of other food commodities that has been of particular concern.

However, arsenic speciation is not easy to perform, which has created some confusion. Inorganic and methylated oxyarsenic species have been a focus of research, but thioarsenates, in which sulfur takes the place of oxygen, have largely been ignored.

Now University of Bayreuth researchers, together with scientists from Italy and China, have for the first time systematically investigated under which conditions, and to what extent, sulphur-containing arsenic compounds are formed in rice-growing soils. It turns out that the amounts of thioarsenates formed are linked to the pH-values of the soils and other environmental parameters.

Formation of thioarsenates in soil, their uptake in rice plants and their potential risks to human health urgently require further research as at least one organic sulphur-containing arsenic compound discovered in rice fields is already known to be carcinogenic.

A bad situation potentially made even worse

Arsenic is one of WHO’s 10 chemicals of major public health concern and in particular for the millions of people who rely on rice as their staple food. Young children are also at risk if rice-based products make up a large part of their diet.

Global warming has the potential to make a bad situation even worse. With an increase in global temperatures higher levels of arsenic in rice will follow and the composition of the arsenic compounds may change, for better or worse.

So please be careful in contributing to global warming.

Higher BPA exposure?

Bisphenol A (BPA) can be found in a wide range of plastics, including food and drink containers, and animal studies have clearly shown that it is a hormon disrupting chemical. In particular, foetal exposure to BPA has in those studies been linked to problems with growth, metabolism, behaviour, fertility and even greater cancer risk.

However, so far most government agencies, although acknowledging the potential negative health effects, have considered exposure to BPA to be at safe levels. As an example, the European Food Safety Authority (EFSA) has evaluated the safety of BPA on several occasions since 2006 and in a 2015 full review of exposure and toxicity concluded that BPA poses no health concern for consumers of any age group (including unborn children, infants and adolescents) at current dietary exposure levels.

The public still concerned

Unfortunately, rightly or wrongly, this is a case where the public risk perception differs from the scientific view of the authorities and no official assurances have been enough to allay the public’s concerns. Many plastics manufacturers have reacted accordingly and removed BPA from their products, although alternatives might be as problematic. We have covered the controversy around BPA in several previous blogs.

As the issue is not going away despite government assurances, a range of further studies have been undertaken and numerous research findings published. Some results have been alarming while others have been more reassuring of the safety of BPA.

BPA exposure estimates

A critical factor is a better understanding of the amount of BPA that enters the human body as this is essential for an accurate risk assessment.

There are two ways of measuring such exposure, either by calculating all sources of external exposure or by using biomonitoring of urine excretion as BPA is completely eliminated through urine. However, rapid metabolism of orally ingested BPA means accurate assessment in humans requires not only measurement of BPA but also of its major conjugated metabolites.

Previously, most biomonitoring studies had to rely on an indirect process to measure BPA metabolites, using an enzyme solution made from a snail to transform the metabolites back into whole BPA, which could then be measured.

New surprising findings

In December 2019, a consortium of scientists led by the Washington State University published results from a study using a direct way of measuring BPA that they had developed to more accurately account for all BPA metabolites. This provided the first evidence that biomonitoring measurements relied upon by regulatory agencies in the past could be flawed, considerably underestimating exposure. In their comparative analysis of 29 urine samples from pregnant women, with the direct method they obtained a geometric mean of 51.99 ng/mL total BPA, while the indirect method yielded a geometric mean for total BPA of 2.77 ng/mL, nearly 19-times lower than the direct method.

Importantly, differences between indirect and direct results increased as exposure increased. Because pregnancy causes physiological changes that might affect metabolism of BPA, the scientists also compared indirect and direct measurements on urine samples from five adult men and five non-pregnant women. The results showed the same trends with differences in BPA levels reflecting the inability of the indirect method to accurately measure the levels of metabolites of BPA.

More confusion

There is now even more confusion as the previous EFSA opinion of 2015 had found fairly close equivalence between dietary and biomonitoring exposure results. Would this mean that both measures are wrong and seriously underestimate exposure to BPA? In that case we could have a real problem. Should we be alarmed?

This might all soon be sorted as in 2018 an EFSA working group of scientific experts has again been charged with evaluating recent published findings on BPA with an updated assessment scheduled for 2020. Will this be the ultimate opinion deciding the issue once and for all?

I for one is eagerly awaiting the pending EFSA opinion.

Not all “bad” cholesterol is equally bad

Cholesterol is essential for all animal life with a typical adult human body containing about 35 g. It is an essential structural component of animal cell membranes and a precursor molecule for all steroid hormones and vitamin D. About one gram is synthesised by the cells of the body per day, while some is excreted through the liver.

Cholesterol is transported in blood bound to proteins called lipoproteins. There are two types of lipoproteins – low-density lipoproteins or LDL and high-density lipoproteins or HDL. Cholesterol bound to LDLs is often called the bad cholesterol and when bound to HDLs the good cholesterol.

Most of us know that high levels of LDL cholesterol can narrow the insides of blood vessels by forming plaques on their walls, thus restricting blood flow. This increases the risk of heart disease and stroke. HDL on the other hand carries the cholesterol to the liver. The liver then flushes it from the body, thus decreasing the risk for heart disease and stroke.

Sounds simple enough? Sorry, time to think again as it is more complicated than that.

Different subclasses of LDL

Contrary to normal wisdom, it has been shown that about 75 percent of patients who suffer heart attacks have total LDL levels that give no indication of cardiovascular risk. What’s going on?

Well, let’s complicate things a little bit.

It has been known since the early 1950s that LDLs comprise of three major subclasses, with particles of different sizes and densities. Subclass A contains more of the larger and less dense LDL particles; subclass I comprises an intermediate group; and finally, subclass B with smaller and denser LDL particles.

It has previously been shown that small and dense LDL is strongly associated with increased cardiovascular risk.

Now new research studying the molecular effect of the different LDL subclasses on blood vessel endothelium has confirmed that of the three subclasses that comprise LDL, only one causes significant damage. LDL subclass B was found to be the most damaging to endothelial function and contributed the most to the development of plaques. Therefore, it’s not the total amount of LDL cholesterol, but rather the concentration of subclass B to the other two, subclass A and subclass I, that should be used to diagnose the risk of heart attack.

However, don’t worry too much about the LDL subclasses as they are more of a diagnostic tool at this time.

Reasons for high levels of bad cholesterol

Let’s make clear from the beginning that most of our circulating cholesterol is actually formed by our own body and genetically determined. So we can blame our parents. However, environmental factors, in particular diet and exercise, appear to also be able to influence the expression of LDL subclasses. 

It was once thought that eating too much of cholesterol-rich foods (such as eggs) was the main cause of high cholesterol. Sure, some foods are high in cholesterol, but indulging in such foods has little influence on our blood levels of cholesterol as such.

Although typical daily cholesterol dietary intake might be around 300 mg, most ingested cholesterol is esterified and poorly absorbed by the gut. The body also compensates for absorption of ingested cholesterol by reducing its own cholesterol synthesis. For these reasons, cholesterol in food has little, if any, effect on long-term concentrations of cholesterol in the blood.

On the other hand, eating too much of foods high in saturated fats is more of a problem, and this has more impact on blood cholesterol levels. The principle mechanism by which saturated fat intake can influence LDL cholesterol is via decreased LDL receptor activity, which in turn decreases liver clearance and excretion of LDL cholesterol.

Mono- or poly-unsaturated fats have the opposite effect, increasing LDL receptor activity and turn-over of LDL cholesterol.

So what can you do?

People with high levels of LDL cholesterol may thus be able to reduce their cholesterol levels by:

  • Limiting foods that have a high saturated fat content (such as many biscuits, cakes and fatty take-away foods)
  • Replacing saturated fats in the diet with mono- or poly-unsaturated fats found in nuts, avocados and oily fish

It is also useful to include more fibre-rich foods in the diet such as fruit, vegetables and wholegrain bread and cereals.

Remember to keep active as it is also an important part of keeping cholesterol levels healthy.

Eating foods enriched with plant sterols has been proven to lower cholesterol levels by up to 10 percent.

Equally, cholesterol-lowering medication has a similar effect and might be necessary if lifestyle changes are not sufficient to reach a desirable cholesterol level. Statin drugs targets the first 18 steps of a complex 37-step process in the formation of cholesterol.

Beware of using mouthwash

I know, I know, mouthwash is no food and this is a blog about food. But bear with me and you will see the connection revealed at the end. Although mouth rinsing has been around for thousands of years it was not until the late 1960’s that effective antibacterial compounds started to be used. Since then commercial interest in mouthwashes has been intense.

New products have been developed that claim effectiveness in reducing bacteria and the associated build-up in dental plaque, a cause of gingivitis. They are also supposed to fight bad breath by controlling anaerobic bacteria that produce unpleasant volatile sulphur compounds.

The downside!

All good then? No, not so fast. Not only will mouthwash not live up to claims in expensive commercials and on product labels, but using a mouthwash can actually make your dental and oral health problems worse.

As the intake of oral antibiotics will disrupt the balance of bacteria in the gut, mouthwash will do the same with the important bacterial balance in the mouth. And just like we need our gut microbiome for general health, we need  our oral microbiome to protect against common issues like cavities, gingivitis and bad breath.

Contrary to popular belief, the common claim of killing “99.9% of germs” does not prevent cavity formation. The oral microbiome actually supports the natural teeth remineralisation and indiscriminately killing the constituent bacteria will eliminate a critical part of the repair mechanism.

Saliva, another key component of the remineralisation process, is typically reduced with mouthwash use. Saliva serves to disturb the oral bacteria that can cause decay, while also depositing important minerals like phosphorous and magnesium onto the teeth.

But there is more!

blood pressure1There is actually a connection between blood pressure and the oral microbiome. Exercise is known to reduce blood pressure, a pleasant bonus of the exertion. But the activity of bacteria in our mouths may determine whether we experience this benefit, according to new research.

Sounds far fetched but there is a plausible explanation.

It was already known that blood vessels open up during exercise, as the production of nitric oxide increases the diameter of the blood vessels, increasing blood flow circulation to active muscles.

What has remained a mystery is how blood circulation remains higher after exercise, in turn triggering a blood-pressure lowering response known as post-exercise hypotension. It might be due to the magic of nitrate metabolism and the influence of the oral microbiome as the nitric oxide in the bloodstream is quickly converted to nitrate within 10 seconds.

Enterosalivary circulation of nitrate

Normally we ingest nitrate with the food we eat; green vegetables like spinach and rocket salad are particularly high in nitrate. In the gastro-intestinal system nitrate is released and enter the blood stream. And here comes the magic. Nitrate is excreted from the bloodstream into the oral cavity by the salivary glands.

Some species of bacteria in the mouth can use nitrate and convert it into nitrite. And when nitrite is swallowed, part of this molecule is rapidly absorbed into the circulation and reduced to nitric oxide. The nitric oxide helps to maintain a widening of blood vessels and a sustained lowering of blood pressure.

Thus the researchers asked the trial participants to rinse their mouths immediately after their exercise with either a mouthwash or water. And they showed that the blood pressure-lowering effect of exercise is significantly reduced when rinsing the mouth with an antibacterial mouthwash, rather than water.

Eating your greens

rucolaThis was new knowledge in relation to exercise but the overall relationship between the oral microbiome and nitrate metabolism was already well known. In 1998, three US scientists received the Nobel prize for their discoveries around the role of nitric oxide.

Several existing studies show that, exercise aside, antibacterial mouthwash can actually raise blood pressure under resting conditions, so this study followed up and showed the mouthwash impact on the effects of exercise.

But in more general terms eating your greens and avoiding the use of a mouthwash will keep your blood pressure under better control, with exercise a bonus.

And there you have your food connection!

Dark chocolate or red wine?

Of course I would like to believe the scientists who claim that eating dark chocolate positively affects our wellbeing and that drinking moderate amounts of red wine improve our health. I like both dark chocolate and red wine and sometimes together to get a double wellness whammy. What’s not to like?

Question is are the scientists actually right? We have written numerous posts about claimed superfoods doing wonders to our health when it is actually the overall diet that is most important, not the individual components as such. Sure we have also fallen into the trap of praising some individual foods as the popular press did this time for fashionable dark chocolate and red wine. Even scientists want to get some attention.

Dark chocolate and health

Let’s start with reviewing the dark chocolate findings. Scientists from the University College London, the University of Calgary and Alberta Health Services Canada assessed data from 13,626 adults from the US National Health and Nutrition Examination Survey. Daily chocolate consumption and type of chocolate was assessed against scores on the Patient Health Questionnaire, which assesses depressive symptoms.

As usual, a range of other factors including height, weight, marital status, ethnicity, education, household income, physical activity, smoking and chronic health problems were taken into account to ensure the study only measured chocolate’s effect on depressive symptoms. Overall, 11.1% of the population reported any chocolate consumption, with 1.4% reporting dark chocolate consumption.

The scientists found that eating dark chocolate positively affected mood and relieved depressive symptoms. As a matter of fact, individuals eating any amount of dark chocolate had 70% lower odds of reporting clinically relevant depressive symptoms than those who reported not eating chocolate at all.

So far so good!

Woman smile

To be believable it is important to find a biological mechanism that can explain the results. And there are several. Chocolate contains a number of psychoactive ingredients which produce a feeling of euphoria and phenylethylamine which is believed to be important for regulating people’s moods. Also, dark chocolate in particular has a higher concentration of flavonoids, antioxidant polyphenols that have been shown to improve inflammation and play a role in the onset of depression.

Another strength of the study is that daily chocolate consumption was derived from two 24‐hour dietary recalls and not from much more dubious food frequency questionnaires that are so common.

And the bad!

Although the study included a large overall sample, there were less than 200 individuals that reported dark chocolate consumption. There could also be other confounding factors not taken into account.

There is some caution expressed by the scientists themselves claiming that further research is required to clarify causation. It could be the case that depression causes people to lose their interest in eating chocolate, or there could be other factors that make people both less likely to eat dark chocolate and to be depressed.

What about red wine and health?

Scientists at King’s College, London have reported that red wine consumption could be linked to better gut health. The study included a group of 916 female twins and tested the effects of consuming beer, cider, red wine, white wine and spirits on the gut microbiome, the micro-organisms found in the digestive tract.

And compared to other alcoholic drinks they found that the gut microbiome of red wine drinkers was more diverse – a sign of better gut health. The researchers speculated that the positive effect of red wine could be due to its higher amount of chemicals called polyphenols that act as antioxidants.

So what to say!

Well, this could be a big thing.

We know that our gut microbiota can affect multiple aspects of our general health and play a role in many illnesses. As a matter of fact, gut microbes are responsible for producing thousands of chemical metabolites affecting our overall metabolism, our immune system and our brain.

We have long known of the unexplained benefits of red wine on heart health. The study findings that moderate red wine consumption is associated with greater diversity and a healthier gut microbiome could at least partly explain its beneficial effects on heart health.

And there is more

As a check on possible genetic or family biases, the scientists found that the twin who drank red wine more often than the related twin had a more diverse gut flora. White wine drinkers who should be socially and culturally similar, had no significant differences in diversity.

Also, in further support of the findings they were shown to be consistent with results from two other studies of similar size in the US (the American Gut project) and Belgium (Flemish Gut Project) basing the conclusions on a total of about 3000 twins.

And in a previous experimental Spanish study from 2012, admittedly involving only ten healthy middle-aged males, the volunteers were given one of three different beverages to drink each day in each of three 20-day periods: normal strength red wine, low alcoholic red wine and gin. Drinking any type of red wine resulted in a larger percent of certain beneficial gut bacteria, but consuming gin had no effect on the gut flora.

So all good?

Not so fast.

Note that again the main study was observational and not experimental and the previous experimental study was very small. The study subjects in the observational study self-reported their food and drink intake with the usual associated bias. The scientists then prospectively tried to statistically link the reported alcoholic drink consumption with test results from the gut microbial analysis. Using twins strengthens the findings but doesn’t conclusively show causality.

There are the usual professional warning that the positives should still be weighed up against the negative impacts of alcohol. Any potential benefits of red wine polyphenols should be considered alongside alcohol’s links to over 200 health conditions, including heart disease and cancers.

But the beneficial effects were achieved by a very moderate glass of red wine a week or even a fortnight.

The moral of the story

If you’re going to eat chocolate pick the dark variety and you will not only have an enjoyable time but you might also be happier.

And the same goes for alcohol consumption. Drink in moderation and pick red wine and the resulting happiness might also be associated with improved health.

Also remember that the beneficial polyphenols found in dark chocolate and red wine can also be found in a range of other foods.

…and you thought more is always better

It’s a truism that most complex life on earth requires oxygen (O2) for its existence. We breathe in oxygen and flush out carbon dioxide (CO2) formed during energy metabolism. But here is the dilemma – oxygen is a highly potent molecule that can cause damage by producing reactive oxygen species like hydrogen peroxide (H2O2) and superoxide (O2) in the body.

Formation of reactive oxygen species is a natural process and part of our normal metabolism. At low levels they have important roles in maintaining basic activities of individual cells as well as optimal functioning of the overall body. However, due to stress, cigarette smoking, alcohol, sunlight, pollution and other factors they can increase dramatically and cause significant damage to cell structures, known as oxidative stress.

The body balance

As life on Earth evolved in the presence of oxygen and its potential negative effects, it was necessary for life to adapt by the evolution of a battery of internal antioxidant systems. Three of those are superoxide dismutase that help in converting superoxide into hydrogen peroxide and oxygen, as well as catalase and gluthation peroxidase that both further degrade hydrogen peroxide to water and oxygen to finish detoxification.

There are also a range of external antioxidants available often associated with so called super foods. Such antioxidants include vitamins A, C and E, and the minerals copper, zinc and selenium. Other dietary food compounds, such as phytochemicals in plants, have even greater antioxidant effects. These include lycopene in tomatoes and anthocyanins found in cranberries among many others.

A diet high in antioxidants may reduce the risk of many diseases, including heart disease and certain cancers. Pulled together oxygen and antioxidants provide an intricate balance supporting life and maintaining health.

Overdoing a good thing

Along comes the chemicals industry. If antioxidants in food are a good thing why not produce them in pure concentrations in the form of a pill to supplement antioxidants from the rest of the diet? As a result there are now a huge range of food supplements available promoted for their antioxidant activities. And sales of antioxidant supplements, including vitamins and minerals, have increased dramatically with the hope that they may prevent premature ageing and promote overall health.

However, studies of antioxidant vitamins and minerals taken as supplements have been disappointing and it appears that the complex array of antioxidants present naturally in plants as well as those the body produces in reaction to stress may be more important.

And there is more. A scientific study published in 2016 showed that excessive antioxidant use may actually have a harmful effect on the normal cell stress response. It might influence a protein called IRE-1, which is located on the outside of the endoplasmic reticulum, a cell structure that makes proteins like insulin. IRE-1 monitors the endoplasmic reticulum, flagging up any abnormal proteins that are created and alerting the cell to apply corrective measures or create a new protein.

Disrupting the natural cell processes can cause irreparable damage.

So what can we learn?

In short, excessive intake of antioxidants, as can happen when taking food supplements, is increasingly bad for you. Blindly consuming large doses of antioxidants is not the best idea, because while your intent would be to protect yourself from damage, you’re potentially interfering with normal cell signals that are helpful and important.

On the other hand there is increasing evidence that the more moderate levels of antioxidants found in whole foods are more effective than when isolated and presented at higher levels in pill form.

A well-balanced diet, which includes consuming antioxidants from whole foods, is best. If you still take supplements, seek supplements that contain all nutrients only at recommended levels. 

As more is not always better.

‘Whiter than white’ – titanium dioxide nanoparticles

‘Whiter than white’ is a claim often used by washing powder manufacturers to describe the superior effects of their products. Equally, ‘whiter than white’ is a product attribute strived for by some food manufacturers although rarely boasted about as such as it might have been achieved through a now questionable food colourant, titanium dioxide.

Titanium dioxide in any form can be identified through the number E171 on the product label. It is commonly used in high quantities in food, chewing gum, toothpaste and some medicines as a whitening agent.

A proportion of this colourant most likely comprise of titanium dioxide nanoparticles.

What are nanoparticles?

Nanoparticles are particles between 1 and 100 nanometres (nm) in size, a thousand times smaller than the width of a strand of hair. Although substances that make up the nanoparticles are not necessarily regarded as toxic, nanoparticles are so small that their behaviour can be quite different from what we see for larger particles of the same substance. This is a new challenge for toxicologists.

While nanoparticles have been commonly used in medicines, food, clothing, and other applications, the possible impacts of nanoparticles, especially their long term effects, are still poorly understood. Nanoparticles in sunscreens and cosmetics can penetrate the skin, and this raises questions about what they can do in the body. Ingested nanoparticles can, and do, get into the body in places where larger particles cannot.

Nanoparticles of titanium dioxide in food

Titanium dioxide has been used in a range of foods, from sweets to processed cheese as consumers are more likely to buy and eat foods that are brighter or more vibrant in colour, as they look fresher. It gives a natural whiteness and opacity to foods, such as ice cream and the icing on cakes, helping to create great-looking food.

Food-grade titanium dioxide has a long history in helping make our meals and snacks aesthetically appealing. Food manufacturers have been using it presumably safely in approved uses for more than 50 years. It is assumed that titanium dioxide doesn’t enter the bloodstream as it passes through the digestive system unchanged and unabsorbed. But what about when the colourant contains nanoparticles?

In the past there has been little understanding of the size of any food-grade titanium dioxide particles, but this is changing with a recent focus on the health impact of nanoparticles in general. To provide the characteristic white colour of titanium dioxide, a large part of the particles must be between 200 and 300 nanometres in size. Particles of this size are not considered nanoparticles. However, the titanium dioxide production process results in a small fraction of the particles being nanoparticles.

The food industry claim that there has been no significant change in the particle size of titanium dioxide supplied to the food industry over the years, but acknowledge that there is a variation allowing for between 11% to 39% of the particles to be of nano size. As they are smaller this would equate to about 3.2% of the mass of any supplied titanium dioxide.

Is titanium dioxide still safe to eat?

The Joint FAO/WHO Expert Committee on Food Additives in 1970 considered it unnecessary to establish an acceptable daily intake (ADI) for titanium dioxide in food. This decision was taken on the basis of the low solubility, poor absorption into internal organs like liver and the absence of acute toxic effects.

In the USA, the FDA considers titanium dioxide as safe for use as a colouring agent in food and in 1966 allowed its addition to food up to a level of one percent. 

In Europe, titanium dioxide has been allowed for use as a food colourant for decades at a level required by food manufacturers to achieve desired effects. In 2016, the European Food Safety Authority (EFSA) published a re-evaluation of titanium dioxide including the potential risks of titanium dioxide nanoparticles to human health. EFSA concluded that, based on the information available, it was no reason for concern.

In Australia, titanium dioxide is an approved food additive and has been used in consumer products for many years. In 2016, Food Standards Australia New Zealand (FSANZ) published a review into the oral ingestion of titanium dioxide, including in nanoscale form, finding that there was not strong evidence to support claims of significant health risks.

In Japan, titanium dioxide is used without limitations other than for certain food categories in which it is not permitted.

In India, titanium dioxide is only authorised for use in chewing gum and bubble gum at not more than one percent, and in powdered concentrate mixes for fruit drinks at not more than 100 mg/kg.

But that is not the end of the matter as more scientific information is published.

What are the new findings?

In 2010, the International Agency for Research on Cancer (IARC) found that there were sufficient evidence in experimental animals for the carcinogenicity of titanium dioxide but not in humans. It thus placed titanium dioxide in a lower category as “possibly carcinogenic to humans” (Group 2B).

In 2016, the Dutch National Institute for Public Health and the Environment (RIVM) estimated likely human exposure to titanium dioxide nanoparticles from food, food supplements and toothpaste and concluded that toxic effects on the liver cannot be excluded. Previous studies with laboratory animals had indicated that the ingestion of very large quantities of titanium dioxide can cause damage to various organs, including the liver.

In 2017, the French Agency for Food, Environmental and Occupational Health & Safety (ANSES) published an expert appraisal of a study on the oral toxicity of titanium dioxide showing potential carcinogenesis-promoting effects in rats. At that time, the Agency stressed the need to conduct new toxicological studies in order to confirm or refute the effects reported in that study.

In 2018, RIVM and the RIKILT research institutes detected titanium dioxide particles in the liver and spleen of humans. At least 24% of the titanium dioxide particles were found to be nanoparticles. The concentration of titanium dioxide particles found in the human liver did not yet result in adverse health effects in laboratory animals, but it exceeded the level that RIVM considers safe for humans.

In 2018, US and Serbian researchers published findings from a study that exposed the fruit fly, Drosophila melanogaster, a common model species in human health research, to an estimated daily human titanium dioxide consumption level for 20 generations. They noticed a change in normal developmental and reproductive dynamics, and an increased genotoxicity. The larval stages were at a higher risk of sustaining damage and this was particularly worrisome, since children tend to consume higher daily concentrations of titanium dioxide than adults.

In 2019, University of Sydney research provided further evidence that nanoparticles may have a substantial and harmful influence on human health. Their mice study found that consumption of food containing titanium dioxide has an impact on the gut microbiota which could trigger diseases such as inflammatory bowel diseases and colorectal cancer.

Titanium dioxide did not change the composition of the gut microbiota, but instead it affected bacterial activity and promoted the formation of biofilms. Biofilms are bacteria that stick together and the formation of biofilm has been reported in diseases such as colorectal cancer.

So what now?

The above results confirm the possibility that the use of titanium dioxide may lead to adverse human health effects. Therefore, it might be that the safety of the present use cannot be fully guaranteed. In response, the European Commission has repeatedly requested EFSA to further re-examine the use of titanium dioxide in food.

EFSA in a reply of June 2018 evaluated four new studies and concluded that their findings highlighted some concerns but with uncertainties, therefore their relevance for the risk assessment was considered limited. Further research would be needed to decrease the level of uncertainties.

In a further statement of May 2019 EFSA claimed it could not identify any major new findings that would overrule its previous conclusions on the safety of titanium dioxide. However, it reiterated the importance of addressing previously identified uncertainties and data gaps, as well as further investigation of in vivo genotoxicity but only after the physico-chemical characterisation of food grade titanium dioxide had been completed.

What can you do?

Well, the answer is not much. Titanium dioxide can be found in more than 3,500 food products and is consumed in a high proportion everyday by the general population.

The highest concentrations are expected in chewing gum (up to 16,000 mg/kg), food supplements delivered in a solid form (up to 12,000 mg/kg), processed nuts (up to 7,000 mg/kg) and ready-to-use salads and sandwich spreads (up to 3,000 mg/kg).

Chewing a single piece of bubblegum can result in an intake of over 5 mg of titanium dioxide. The estimated daily maximum consumption of titanium dioxide by children is up to 32.4 mg/kg body weight.

To put those dietary intake levels into perspective hypothetical upper safe levels for dietary intake of between 0.4 and 5 mg/kg body weight per day have been calculated from rodent studies.

You could stop chewing gum but it would not help much. The best hope is that studies currently under way will produce conclusive results so that authorities can either fully clear titanium dioxide for use in food, limit its use or fully ban it from food.

Most of us have to wait and see. However, if you live in France you might benefit from the French government decision to ban the addition of titanium dioxide in food from 1 January 2020.

Filmjölk’s health benefits

In a previous post we covered fraudulent milk products being at the top of food cheating. Today we turn it around by covering the health benefits of consuming filmjölk. Never heard of filmjölk? Just read on.

First you need to know that people in Scandinavian countries are masters of food preservation because of the historic need to guarantee food supply during harsh winters. By necessity a range of cultured, naturally fermented foods were born. They include gravlax, pickled herring, cheeses and sourdough breads, pickled beetroot and, of course, filmjölk.

Filmjölk is similar to cultured buttermilk or kefir in consistency but is not the same as it is a unique product. It is sometimes translated as “sour milk” but there is a wide range of such products. So in the absence of an official English translation the name filmjölk or filmjolk is getting international tracking.

Different varieties of filmjölk are commonly found in the Scandinavian countries, but are also popular in neighbouring Estonia, Latvia and Lithuania. Somewhat surprisingly, filmjölk has found its way into supermarkets in the USA, the United Kingdom and Australia.

How is it produced

Commercial filmjölk is made from pasteurised, homogenised, and standardised cow’s milk by fermenting the milk with a variety of bacteria from the species Lactococcus lactis and Leuconostoc mesenteroides. The bacteria metabolise lactose into lactic acid so filmjölk is easier to digest if you are lactose intolerant. The acid gives filmjölk a sour taste and causes proteins in the milk to coagulate, thus thickening the product. The bacteria also produce a limited amount of diacetyl, a compound with a buttery flavour, which gives filmjölk its characteristic taste.

Prior to the commercial production of filmjölk, many families made their own filmjölk at home. A filmjölk-like product has probably been around since the Viking Age or longer. Nowadays it is possible to buy the bacterial cultures to make your own filmjölk if you want to.

Potential health benefits of filmjölk

The bacteria in filmjölk produce folic acid, an important vitamin for the development of growing cells. Filmjölk is also high in lactic acid, which is known to improve the nutritional value of food, and may alleviate intestinal infections and improve the digestion of lactose. 

Probiotics are live bacteria and yeasts that when consumed confer health benefits on humans. Particular probiotic versions of filmjölk on the market usually add various strains of Lactobacillus acidophilus and Bifidobacterium lactis.

Probiotic foods have gained a lot of attention in both research and mainstream media lately. There has been a huge growth in interest in probiotic products over the last decades around the world. There is a growing body of evidence to support their importance in our diet; both to treat and prevent specific diseases and as part of a healthy diet. 

Possible benefits include:

  • improving heart health
  • counteracting lactose intolerance
  • increasing iron levels in the blood
  • lowering the risk of yeast infections
  • improving the symptoms of diarrhea and constipation
  • reducing cholesterol levels
  • boosting the immune system
  • reducing the symptoms of certain allergies
  • fighting inflammation

An impressive list should it be true. The European Food Safety Authority (EFSA) has evaluated several claims in relation to probiotic foods. In 2011, it agreed that certain probiotic strains could assist in the digestion of lactose. Other applications for health claims on probiotics have been submitted for evaluation to EFSA but no further application has received a positive opinion. 

What to believe

Unfortunately, many of the positive health effects of probiotics are strain-specific, which is one of the reasons these effects are so complicated to evaluate. A “strain” refers to a specific group within a species and there are often many such strains.

This strain specificity of probiotic properties has made research into the health benefits of probiotics and labelling of probiotic microbes much more difficult.

But why worry about that? Irrespective of the belief in potential health benefits you can enjoy filmjölk just for the taste of it. With some unspecified health benefits on the side.

Food fraud – milk

Food fraud is nothing new, but the intensity and frequency have been on the rise. From counterfeit extra-virgin olive oil to intentional adulteration of spices and the manufacturing of fake honey, food fraud has been estimated to be a $US40 billion a year industry. In a series of posts we will cover a range of recent issues.

Milk is the third in our series on fraudulent food

Next to prostitution, historians consider counterfeiting the world’s second oldest profession. Similar to fraudulent honey and olive oil, which we covered in previous posts, food fraud involving milk has been around for centuries and is actually to my surprise number one on the list of food tampering issues worldwide, due in particular to current cheating in the developing world.

But the Western world has had its problems too. It was common in the old German Empire to dilute milk by 50 per cent and to restore the original consistency by adding a range of substances like sugar, flour, chalk or gypsum. Spoiled or otherwise contaminated milk was sold without hesitation.

In the mid-19th century, New York’s dairy farmers increased their profits by feeding their cows with cheap waste from distilleries. This resulted in watery and blue-tinted milk that farmers mixed with starch, plaster, chalk and eggs to improve texture and colour, then diluted further with water.

Milk fraud has now spread to the developing world due to an increased demand for milk.

Increased milk consumption

Milk in its natural form has a high food value, since it is comprised of a wide variety of nutrients which are essential for proper growth and maintenance of the human body. In recent decades, there has been an upsurge in milk consumption worldwide, especially in developing countries, and it is now forming a significant part of the diet for a high proportion of the global population.

As a result of the increased demand, some unscrupulous producers are indulging in milk fraud. This malpractice has become a common problem in the developing countries, which might lack strict vigilance by food safety authorities.

One of the oldest and simplest forms of milk fraud is through the addition of variable volumes of water to artificially increase its volume for greater profit. This can substantially decrease the nutritional value of milk, and if the added water is contaminated there is a risk to human health because of potential waterborne diseases. For infants and children this may be a serious concern as they are more vulnerable, at a critical stage of growth and development and are dependent on milk products for supplies of vital nutrients. Babies fed fraudulent milk are at risk of malnutrition and even death.

Adulterants added to milk

Although the vast majority of food fraud incidents do not pose a public health risk, there have been fraud cases that have caused extensive illness. Perhaps the most widely cited, high-profile case involved the addition of melamine to milk-based products to artificially inflate protein values. In 2008, it was reported that melamine-contaminated baby formula had sickened an estimated 300,000 Chinese children with symptoms of irritability, dysuria, urination difficulties, renal colic, hematuria, or kidney stone passage. Hypertension, edema, or oliguria also occurred in more severe cases, killing a reported 6 infants. 

A range of other inferior cheaper materials may be added to diluted milk to increase the thickness and viscosity of the milk, to maintain the composition of fat, carbohydrate, and/or protein and to increase shelf-life. They include reconstituted milk powder, urea, rice flour, salt, starch, glucose, vegetable oil, animal fat, and whey powder, or even more hazardous chemicals including formalin, hydrogen peroxide, caustic soda, and detergents.

Some of these additions have the potential to cause serious health-related problems.

Toxic effects caused by some milk adulterants

The presence of urea in milk may cause severe human health problems such as impaired vision, diarrhea, and malfunctioning of the kidneys. It may also lead to swollen limbs, irregular heartbeat, muscle cramps, chills and shivering fever, and cancers, though these are less likely with the concentrations present in the adulterated milk.

Formalin is highly toxic to humans in small amounts and is classified as a carcinogen. Its ingestion is known to cause irritation, often leading to dry skin, dermatitis, headaches, dizziness, tearing eyes, sneezing and coughing, and even the development of allergic asthma.

Hydrogen peroxide damages the gastrointestinal cells which can lead to gastritis, inflammation of the intestine, and bloody diarrhea.

Detergents have been shown to cause food poisoning and gastrointestinal complications. Some detergents also contain the toxic ingredient dioxane, which is carcinogenic in nature.

Difficult to quantify food fraud

It is not known how widespread milk fraud is as those who commit fraud want to avoid detection and do not necessarily intend to cause physical harm. Thus, most incidents go undetected since they usually do not result in a food safety risk and consumers often do not notice a quality problem.

The full scale of food fraud is not known, as the number of documented incidents may be a small fraction of the true number of incidents. However, some researchers contend that food adulteration is not necessarily more common now, but reputational repercussions are certainly more far-reaching with today’s worldwide media coverage.

Detecting food fraud relies on testing. As new tests are developed we get better at detecting frauds, but the fraudsters will always be looking for new ways to cheat those tests. 

Newer technology will help fight food fraud in the future. These include tracers and edible inks that can be used to tag foods, biomarkers, and DNA fingerprinting. 

While it might seem alarming to hear reports of fake and adulterated foods, this might actually be a good thing, because it means testing and surveillance is working.

Toothpaste danger?

toothbrushingToothpaste has been around for a very long time with historic references as far back as 377 BC. Modern toothpastes are very different though and contain a myriad of ingredients to improve their mechanical properties, appearance, or smell in order to appeal to consumers. Should we be worried?

Two caveats are needed upfront.

First one, please note the question mark in the title. I am not saying that toothpaste is dangerous, just asking the question after some recent experiences.

Second one, although toothpaste is not food, and this blog is about food, you will at least inadvertently swallow some, and some ingredients will easily be absorbed through the lining of the mouth with a 90% efficiency.

So here we go.

The best toothpaste ever

Some years back our brand of toothpaste exclaimed it was clean and fresh. We were quite happy with that, what more could you ask for? But the marketing gurus obviously thought you needed more so changed it to extra clean and fresh. That’s fine too we thought. We don’t mind having extra clean teeth.

Never satisfied the marketing gurus wanted something more so changed to extra clean and lasting fresh. Well, come on now, didn’t the freshness last before? But there’s more, now the toothpaste exclaims it is extremely clean and lasting fresh. This must be the best toothpaste ever. And this is how they describe the effects:

  • This toothpaste doesn’t just freshen your breath, it invigorates it.
  • Thanks to its micro-active foam that leaves you with a pure breath sensation that last and a feeling of clean like no other.

So what is different?

Several warnings

Curious, for once we decided to read the small print on the tube. Upfront there are several warnings:

  • “Do not swallow, be sure to spit out”
  • “Not for use by children 6 years of age and under”
  • “Do not brush more than three times a day”
  • “If irritation occurs discontinue use”

Quite a list of warnings and as it happened one of us had an “irritation” and had to stop using it. The label claimed it could possibly be an allergy to one of the ingredients.

Checking the ingredients

So what is in this toothpaste? Quite a lot as it happens, but at least no sugar it claims upfront. That’s a relief.

First on the list of ingredients is water and not much to say about that.

Second is the sugar substitute sorbitol followed much further down the list by the artificial sweetener sodium saccharin. Of course, even if there is no sugar, a sweet taste is important for palatability. Saccharin has been shown to cause bladder cancer in rats, but through a mechanism that is not available in humans. No harmful effects are expected from those two ingredients although artificial sweeteners like saccharin might influence the gut flora. This is still to be clarified.

Hydrated silica is an odourless, tasteless, white, gelatinous substance, which is chemically inert. As a fine gel it is abrasive and helps to remove plaque. It is generally considered to be safe, although it might wear down the enamel exposing the dentin underneath.

Glycerin is a colourless, odourless, viscous liquid that is sweet-tasting and non-toxic, so no problem there.

Pentasodium triphosphate is produced on a large scale as a component of many domestic and industrial products, particularly detergents. It has very low human toxicity but in volume can have negative environmental effects by supporting algal growth.

PEG-6 (polyethylene glycol) belongs to a group of petroleum-based compounds that are widely used in cosmetics as thickeners, solvents, softeners, and moisture-carriers. In itself not considered toxic although it can inadvertently be contaminated by other toxic compounds depending on the manufacturing process. A minority of people are allergic to PEG compounds.

Alumina or aluminium oxide is primarily used as an abrasive and thickening agent, but also functions as an anti-caking agent and absorbent. It is safe to use for cosmetic purposes. However, it must be noted that aluminum is a neurotoxin.

chemicalsSodium lauryl sulfate is a surfactant responsible for the foaming action of the toothpaste but it also interferes with the functioning of taste buds by breaking up phospholipids on the tongue. As it is further down the ingredient list the amount in the toothpaste should be fairly low but it should be noted that it has been linked to skin irritation and painful canker sores, with research suggesting that the compound should not be used in people with recurring sores. Sodium lauryl sulfate could potentially be contaminated with 1,4 dioxane, a carcinogenic byproduct.

Flavour is not further specified but might be mint as it is common in toothpaste.

Xanthan gum is a common food additive. It is an effective thickening agent and stabiliser to prevent ingredients from separating. It can cause some side effects such as flatulence and bloating in high doses, but the low amount in toothpaste should not be a problem.

Cocamidopropyl betaine is a mixture of closely related organic compounds derived from coconut oil and dimethylaminopropylamine. It is used as a surfactant and foam booster. It can be an irritant particularly if impurities like amidoamine and dimethylaminopropylamine are not tightly controlled.

Sodium citrate possesses a saline, mildly tart flavour. It is commonly used for flavour or as a preservative. The chemical has been verified to be of low concern.

Titanium dioxide is often used as a pigment, brightener, and opacifier, which is an ingredient that makes a formulation more opaque. Although not relevant for toothpaste, if in powder form and inhaled it can possibly cause cancer. However, titanium dioxide in toothpaste may become dangerous when it is nanoparticle size, an issue still to be resolved.

Carrageenan is an extract from a red seaweed commonly known as Irish Moss. It is a native to the British Isles, where it’s been used in traditional cooking for hundreds of years. Some scientists claim that it can cause a range of health effects while others claim it is perfectly safe. Although the jury is still out, amounts in toothpaste is supposedly too low to cause any health effects.

Sodium fluoride is another controversial compound. It can be toxic in high doses but the low doses ingested through toothpaste and fluoridated water can in a worst case situation cause some slight discolouration of children’s teeth. There have only ever been three reported cases of fluoride toxicity associated with the ingestion of fluoride-containing toothpaste. One involved a 45 year old woman with unusual swelling and pain in her fingers. As it happened the woman admitted to the regular ingestion of large amounts of toothpaste, consuming a tube of it every two days because she “liked the taste”. When asked to switch to a non-fluoride form of toothpaste, her  condition subsided.

Zinc chloride polishes the teeth and reduces oral odour by destroying or inhibiting the growth of microorganisms. We need zinc for healthy development, but in high doses it  might cause nausea, vomiting, diarrhea, metallic taste, kidney and stomach damage in some people. Levels in toothpaste are generally considered as safe.

Sodium hydroxide is a good example of a compound that can cause harm in high doses but is completely harmless in a diluted form.

Limonene is a chemical found in the peels of citrus fruits and in other plants. It is used to make medicine and as a flavouring. Limonene is safe in food amounts. It also appears to be safe for most people in medicinal amounts when taken by mouth for up to one year.

CI 74160 Phthalocyanine blue BN is a bright, crystalline, synthetic blue pigment. The compound is non-biodegradable, but not toxic to fish or plants. No specific dangers have been associated with this compound.

CI 74260 Phthalocyanine green G is a synthetic green pigment available in the form of a soft powder. Classified as not expected to be potentially toxic or harmful although one or more animal studies have shown toxic effects at moderate doses.

So what to do

white_teeth

Well I am happily continuing to use the toothpaste but with some reflections each time. I wouldn’t mind if they removed the blue and green colourings. Sure it looks nice with blue and green stripes among the white but is it really necessary. And to the whiter than white from titanium dioxide, do we need the nanoparticles?

I am happy that they have resisted putting triclosan in their toothpaste to stop bacterial growth as the zinc chloride might to the job as efficiently. But I can only hope that they have full control of their chemistry to avoid toxic byproducts being formed.

Regulators in different countries provide some controls for toothpastes but I would be surprised if there were any extensive testing of the product on the market.

On the other hand we only use about 0.3g of toothpaste per brush so exposure to any of the chemicals in the toothpaste is minimal.

Good to know!