Consuming micro- and nanoplastics

We seem quite good at inventing ‘things’ and we rush them to market before giving enough thought to potential negative consequences. The question is will we ever learn? Ulrich Beck, a past sociology professor at the University of Munich, pointed to inherent long-term risks with new products that are often disregarded by an enthusiastic subordination of nature by science and technology. (Image by storyset on Freepik)

There are many examples of how this can backfire.

DDT was hailed as a wonder chemical that would revolutionise agriculture until Rachel Carson published her book ‘Silent Spring’ in 1962. It is now known that DDT caused direct mortality of some birds by poisoning their nervous system, caused bird eggs to have thin shells and reduced levels of a hormone necessary for female birds to lay eggs. It could indeed lead to a silent spring.

PFAS are a large, complex group of manufactured chemicals that are ingredients in various everyday products. They are used to keep food from sticking to packaging or cookware, make clothes and carpets resistant to stains, and create firefighting foam that is more effective. Now we know of numerous human health effects including altered metabolism and fertility, increased risk of being overweight or obese, and reduced ability of the immune system to fight infections. Something we have to live with as PFAS are persistent chemicals spread everywhere in nature.

Neonicotinoids are insecticides that have been repeatedly called ‘perfect’ for use in crop protection. Since their introduction in the early 1990s, neonicotinoids have become the most widely used insecticides in the world on a variety of crops. However, in a 2013 report by the European Food Safety Authority it was stated that neonicotinoids pose an unacceptably high risk to honey bees, and that the industry-sponsored science upon which regulatory agencies’ claims of safety have relied may be flawed and contain data gaps not previously considered. As bees, consisting of around 20,000 species worldwide, are one of the primary pollinators of both native plants and agricultural crops the impact of neonicotinoids could spell disaster for worldwide food production. Bumblebees are also economically important pollinators and appear to be particularly sensitive to neonicotinoid pesticides, which affect both bumblebee colony growth and foraging efficiency. It is clear that we overuse pesticides at our own peril because human and natural environments are unquestionably linked. And still many countries have no restrictions on neonicotinoid use.

Do you want some plastics with that?

And so we come to plastics, such a useful innovation for many aspects of life. Attempts to produce plastic materials started already in the middle of the 19th century. However, the world’s first fully synthetic plastic was Bakelite, invented in New York in 1907. Many chemists have since contributed to the science of developing a variety of plastic materials. Over 9 billion tonnes of plastics are estimated to have been made over the last 70 years.

The success of plastics has caused widespread environmental problems due to their slow decomposition rate in natural ecosystems. At the macro level, plastic pollution can be found all over the world creating garbage patches in the world’s oceans and contaminating terrestrial ecosystems.

Of all the plastics discarded so far, OECD calculated that only 19% had been incinerated and 9% recycled. However, the real problem can be found at the micro (or even the smallest nano) level.

Microplastics can either come from a primary source like microfibers from clothing, microbeads in cosmetics, and plastic pellets. Or there are secondary microplastics arising from the degradation of larger plastic products through natural weathering processes after entering the environment. Microplastics can now be found wherever we look and will find their way into the food we eat.

Studies have found microplastics in foods including tea, salt, seaweed, milk, seafood, honey, sugar, beer, vegetables, fruit and soft drinks. It has been estimated that 5 g of plastic particles on average enter the human gastrointestinal tract per person per week. A recent Australian survey of microplastics in rice found that consumption of a single serve of rice may contribute 3-4 mg of microplastics, equivalent to an intake of around 1 g per person annually. Even tap water contains microplastics while bottled water contains even more.

So what’s the problem?

The actual plastic polymers are not the problem although residues of the monomers used in the manufacture of the complex polymers may be toxic. What is more of a problem is the variety of additives used to change the properties of the plastic, some of which can be quite toxic. These include plasticisers, flame retardants, heat stabilisers and fillers among many others.

According to current knowledge, microplastics at 0.001 to 5 millimetres in size are considered to pose a comparatively low risk to human health as they are considered to be too ‘bulky’ to be absorbed by human cells and are largely excreted again. However, experimental studies indicate that such particles passing through the gastrointestinal tract can lead to changes in the composition of the gut microbiome and in turn the development of metabolic diseases such as diabetes, obesity or chronic liver disease.

The situation is different with smaller particles, submicro- and nanoplastics. These particles are less than 0.001 millimetre in size. A laboratory study by the German Federal Institute for Risk Assessment found that the smaller the particles, the more they were absorbed. While microplastics only “seeped” into the cell to a small extent, particles in the submicrometre range could be measured in larger quantities in intestinal and liver cells.

Whether ingested micro- and nanoplastics pose a health risk is being investigated in numerous studies but is largely unknown to date. Using specific analyses there are indications that they could activate mechanisms involved in local inflammatory and immune responses and could crucially be involved in carcinogenesis.

What to do?

Not easy to say at this stage. We could of course try to reduce the use of plastics to diminish future contamination, but this is easier said than done with the ubiquitous use of plastics for all kinds of applications.  Some reduction can be achieved by washing fruit and vegetables before consumption. Washing rice before cooking reduced the microplastic content by around 25%.

American researchers pointed out that without a well-designed and tailor-made management strategy for end-of-life plastics, humans are conducting a singular uncontrolled experiment on a global scale, in which billions of metric tons of plastic material will accumulate across all major terrestrial and aquatic ecosystems on the planet.

We can do better!

Nothing wrong with cranberries

Sure there is nothing wrong with eating cranberries. Although the same thing could be said of consuming any fruits as they are all considered healthy so there is some competition. That might be the reason why the Cranberry Institute felt obliged to provide funding for two recent studies showing the beneficial effects of cranberry consumption on memory and blood flow.

But can you believe the conclusions of studies tainted by respective industry contributions? Read on so you can judge for yourself.

Cranberries might improve cardiovascular health

The Cranberry Institute provided financial support to a recent clinical trial which found that daily consumption of cranberries for one month improved cardiovascular function in healthy men.

The study included 45 healthy men who consumed 9g of freeze-dried cranberry powder equivalent to a cup of 100g of fresh cranberries per day or a placebo for one month. Incredibly, the study found that those consuming cranberries showed significant improvements in flow-mediated dilation of blood vessels already two hours after first consumption and after one month of daily consumption indicating both immediate and long-term benefits. The researchers claimed that consumption of cranberries as part of a healthy diet can help reduce the risk of cardiovascular disease by improving blood vessel function.

Sure there is evidence that links polyphenols from berries with heart health benefits. And as it happens, cranberries are rich in unique proanthocyanidins that have distinct properties compared to polyphenols found in some other fruits.

Cranberries might also improve memory

The Cranberry Institute wanted more good news by financially supporting a study investigating the impact of cranberry consumption on memory and brain function. Past studies have shown that higher dietary flavonoid intake is associated with slower rates of cognitive decline and dementia. And foods rich in anthocyanins and proanthocyanidins, which give berries their red, blue, or purple colour, have been found to improve cognition.

Thus, the commercially funded research team from the University of East Anglia (UK) investigated the impact of eating cranberries for 12 weeks on brain function and cholesterol among 60 cognitively healthy participants between 50 to 80 years old. Again, half of the participants consumed freeze-dried cranberry powder, equivalent to a cup of 100g of fresh cranberries, daily. The other half consumed a placebo.

The study, one of the first to examine cranberries and their long-term impact on cognition and brain health, showed that consuming cranberries significantly improved memory of everyday events (visual episodic memory), neural functioning and delivery of blood to the brain (brain perfusion).

The cranberry group also exhibited a significant decrease in LDL or ‘bad’ cholesterol levels, known to contribute to the thickening or hardening of the arteries caused by a build-up of plaque. The researchers claimed that the potentially improved vascular health may have in part contributed to the improvement in brain perfusion and cognition.

Of course the researchers considered the findings encouraging, especially as a relatively short 12-week cranberry intervention was able to produce significant improvements in memory and neural function. They see it as an important foundation for future research in the area of cranberries and neurological health.

Ocean Spray Inc. also at it

The U.S. cranberry juice giant, Ocean Spray Inc., has spent millions of dollars funding research to try to prove the health aspects of consuming cranberry juice. There has long been a myth that cranberry juice can prevent urinary tract infections (UTIs). Back in the day, before antibiotics were a thing, acidification of the urine was a recommended treatment for UTI. It was believed that because cranberries are acidic, they would make urine more acidic to fight off bacteria. This was attributed to formation of hippuric acid through metabolism of the quinic acid present in cranberry juice.

Unfortunately, later studies reported that the concentration of hippuric acid in the urine was insufficient for an antibacterial effect unless very large volumes of cranberry juice were ingested.

Subsequently, proanthocyanidins present in cranberries as well as blueberries were reported to inhibit binding of the type 1 P-fimbriae of Escherichia coli to uroepithelial cells, preventing bacterial adherence within the urinary tract.

However, researchers from the University of Manitoba found that the two proposed mechanisms for a beneficial effect of cranberries on UTIs had not yet been shown to have a role in human infection.

EFSA and FDA dismisses cranberry health claims

In 2009, Ocean Spray Inc. submitted a health claim for cranberry juice to the European Food Safety Authority (EFSA) supported by several scientific studies. However, the EFSA Panel concluded that the evidence provided was not sufficient to establish a cause and effect relationship between the consumption of Ocean Spray cranberry products and the reduction of the risk of UTIs in women by inhibiting the adhesion of certain bacteria in the urinary tract.

In 2017, Ocean Spray Cranberries Inc. tried again, this time logging a health claim for cranberry juice with the U.S. Food and Drug Administration (FDA). After reviewing the petition and other evidence related to the proposed health claim, the FDA determined that the scientific evidence supporting the claim did not meet the “significant scientific agreement” standard required for an authorized health claim. However, at the same time FDA announced that it does not intend to object to the use of certain ‘qualified health claims’ regarding consuming certain cranberry products and a reduced risk of recurrent urinary tract infection (UTI) in healthy women. As long as a qualifying statement was included on the label stating that FDA has concluded that the scientific evidence supporting this claim is limited and inconsistent.

Not looking convincing?

It’s up to you to decide what you think. As I said in the beginning there is nothing wrong in eating cranberries as they would be as healthy as any other berries.

To help you make up your mind here is a quote from the well known nutrition expert Marion Nestle:

“Without even getting into whether cranberry powder is equivalent to cranberries, whether anyone can eat cranberries without adding their weight in sugar, or whether any other fruit might have similar effects, we should ask whether it makes any sense at all to think that any one single food could boost memory and prevent dementia in the elderly.”

So there you have it.

The Coffee Consumption Genes

Are you desperate for a cup of coffee just now? The urge might be determined by your genes. I almost didn’t believe it when the newspaper reported that scientists had explored the genes of pregnant women to predict the amount of coffee they consume and its potential impact on their pregnancy.

I have been heavily involved in developing elaborate protocols to explore population food consumption in detail. And now all you have to do is look at the genes. So I did some research and it seems to be true that coffee drinking behaviour is at least partly due to genetics, with a specific set of genetic variants affecting how much coffee we drink.

What the researchers found

In the reported findings, researchers at the University of Queensland used a method called Mendelian randomisation which used eight genetic variants that predicted pregnant women’s coffee drinking behaviour and examined whether these variants were also associated with birth outcomes. Current World Health Organization guidelines say pregnant women should drink less than 300mg of caffeine, or two to three cups of coffee per day. However, the researchers through their genetic analyses found that coffee consumption during pregnancy might not itself contribute to adverse outcomes such as stillbirth, sporadic miscarriages and pre-term birth or lower gestational age or birthweight of the offspring.

As a caveat just to be on the safe side, the researchers emphasised that the study only looked at certain adverse pregnancy outcomes, and it might be possible that coffee consumption could affect other important aspects of foetal development. 

This has been known for some time

The important outcome is that genetics can be used to estimate the amount of coffee consumed. This has actually been known for some time. Heritability refers to degree of genetic influence and can vary from 0 (not heritable) to 1 (completely inherited).

A review published in 2010, reported that twin studies had estimated heritability of coffee consumption by comparing monozygotic twins, who share the common familial environment and the same genes, to dizygotic twins, who also share common familial environment but only half of the genetic material. These studies found that heritability of coffee consumption varied from 0.30 to 0.60 in different populations. Heavy consumption, defined as more than 6 cups of coffee daily, had a heritability of 0.77. A few conclusions can be drawn. First, heavy consumers seem to differ from moderate and light coffee users on several accounts. Secondly, heavier coffee users appear to be more influenced by genetics than lighter caffeine users. 

So far the studies confirmed the possibilities of coffee consumption inheritance without identifying the individual genes responsible for such differential inheritance pattern. 

And the complicated stuff

So genetics have long been suspected of contributing to individual differences in coffee consumption. However, pinpointing the specific genetic variants has been challenging. Thus, researchers as part of the Coffee and Caffeine Genetics Consortium conducted a genome-wide meta-analysis of more than 120,000 regular coffee drinkers of European and African American ancestry. They identified two variants that mapped to genes involved in caffeine metabolism, POR and ABCG2 (two others, AHR and CYP1A2 had been identified previously). Two variants were identified near genes BDNF and SLC6A4 that potentially influence the rewarding effects of caffeine. Two others – near the GCKR and MLXIPL genes involved in glucose and lipid metabolism – had not previously been linked to the metabolism or neurological effects of coffee.

The findings suggest that genes drive people to naturally modulate their coffee intake to experience the optimal effects exerted by the caffeine in coffee and that the strongest genetic factors linked to increased coffee intake likely work by directly increasing caffeine metabolism.

But there is more

People who like to drink their coffee black also prefer dark chocolate, a new Northwestern Medicine study found. The reason is also in their genes.

The scientists found that coffee drinkers who have a genetic variant that reflects a faster metabolism of caffeine prefer bitter, black coffee. And the same genetic variant is found in people who prefer the more bitter dark chocolate over the more mellow milk chocolate.

The reason is not because they love the taste, but rather because they associate the bitter flavour with the boost in mental alertness they expect from coffee.

It is interesting because these gene variants are related to faster metabolism of caffeine and not related to taste. These individuals metabolise caffeine faster, so the stimulating effects wear off faster as well. So, they need to drink more. They learn to associate bitterness with caffeine and the boost they feel. When they think of coffee, they think of a bitter taste, so they enjoy dark coffee and, likewise, dark chocolate.

A new era

In the past, when scientists studied the health benefits of coffee and dark chocolate, they had to rely on epidemiological studies, which only confer an association with health benefits rather than a stronger causal link. The new research shows these genetic variants can be used more precisely to study the relationship between coffee and health benefits.

And who knows, in the future there might be other genetic markers found that drive our food consumption behaviour.

A Word About Zinc

I assume you’re not too worried about zinc intake. This might be correct for most people in the developed world, with some important exceptions, as zinc is naturally found in a wide variety of both animal and plant foods. Still you should be aware that we all need a constant supply of zinc as it is considered an essential nutrient for the human body involved in numerous different processes.

However, worldwide zinc deficiency can be a serious problem as it affects about two billion people in the developing world and is associated with many diseases. Zinc deficiency causes growth retardation in children, delayed sexual maturation, infection susceptibility, and diarrhea.

Consumption of excess zinc may in turn cause ataxia, lethargy, and copper deficiency. So a balance is important.

The magic of zinc

Zinc is the second most abundant trace mineral in our bodies after iron and is present in every cell. It is necessary for the activity of over 300 enzymes that aid in metabolism, digestion, nerve function and many other processes. It is critical for the development and function of immune cells and is also fundamental to skin health, DNA synthesis and protein production. Zinc deficiency can lead to a weakened immune response, particularly important in covid times. Zinc supplements can significantly reduce the risk of infections and promote immune response in older adults

Body growth and development relies on zinc because of its role in cell growth and division. Zinc is commonly used in hospitals as a treatment for burns, certain ulcers and other skin injuries. Because it plays critical roles in collagen synthesis, immune function and inflammatory response, it is necessary for proper healing.

Oddly, zinc deficiency will reduce our ability to taste or smell our food and surroundings because one of the enzymes crucial for proper taste and smell is dependent on this nutrient.

A pretty impressive list.

Too little or too much zinc intake

Although severe zinc deficiency is rare, milder forms of zinc deficiency are more common, especially in children in developing countries where diets are often lacking in important nutrients. Symptoms of mild zinc deficiency include diarrhea, decreased immunity, thinning hair, decreased appetite, mood disturbances, dry skin, fertility issues and impaired wound healing.

Just as a deficiency in zinc can cause health complications, excessive intake can also lead to negative side effects. This is mainly related to going overboard with consumption of too much zinc through food supplements. Symptoms of toxicity include nausea, vomiting and loss of appetite. It can cause diarrhea, abdominal cramps and headaches. Ingesting too much zinc can also interfere with the absorption of copper and iron.

Zinc’s immune-boosting properties

The importance of zinc for a properly functioning immune system is intriguing. Although well known in principle, new details have recently come to light.

Results published in 2022 by scientists at the Fred Hutchinson Cancer Center in Seattle looked at the importance of adequate zinc intake to boost immune function. They revealed two ways that the mineral supports immunity and suggested how it could be used to improve health. The team discovered that zinc is needed for the development of disease-fighting immune cells called T cells and prompts regeneration of the thymus, the immune organ that produces T cells.

The scientists found that the thymus of mice deprived of dietary zinc shrink and produce notably fewer mature T cells, even after as little as three weeks of a no-zinc diet. They also showed that without zinc, T cells cannot fully mature. Conversely, with extra zinc T cells recover faster than normal.

They are now looking into how zinc may fit in with how the immune system repairs itself after stressors like chemotherapy, blood stem cell transplant and radiation exposure or how zinc can assist people with chronic immune decline that accompanies ageing.

Vulnerable population groups

Although zinc deficiency is uncommon, vegetarians, some pregnant women, 7-12 months old infants, alcoholics and people with some digestive disorders need to consider their zinc intake.

The bioavailability of zinc from vegetarian diets is lower than from non-vegetarian diets. In addition, vegetarians typically eat high levels of legumes and whole grains, which contain phytates that bind zinc and inhibit its absorption.

Pregnant women, particularly those starting their pregnancy with marginal zinc status, are at increased risk of becoming zinc insufficient due, in part, to high fetal requirements for zinc. Lactation can also deplete maternal zinc stores.

Breast milk provides sufficient zinc for the first 6 months of life but does not provide recommended amounts of zinc for infants aged 7–12 months. In addition to breast milk, infants aged 7–12 months should consume age-appropriate foods containing zinc.

Up to 50% of alcoholics have low zinc status because ethanol consumption decreases intestinal absorption of zinc and increases urinary zinc excretion. In addition, the variety and amount of food consumed by many alcoholics is limited, leading to inadequate zinc intake.

Digestive disorders such as ulcerative colitis, Crohn’s disease, and short bowel syndrome can decrease zinc absorption and increase endogenous zinc losses. Other diseases associated with zinc deficiency include malabsorption syndrome, chronic liver disease, chronic renal disease, sickle cell disease, diabetes, malignancy, and other chronic illnesses. Chronic diarrhea also leads to excessive loss of zinc.

So where to find zinc?

Many animal and plant foods are naturally rich in zinc, making it easy for most people to consume adequate amounts.

Foods highest in zinc include fish and shellfish, meat and poultry, legumes, nuts and seeds, dairy products, eggs, whole grains and vegetables like mushrooms, kale, asparagus and beet greens.

There is a caveat.

As is often common for minerals, animal products contain zinc in a form that is easily absorbed by the body. On the other hand zinc in plant-based sources is absorbed less efficiently as phytates—which are present in whole-grain breads, cereals, legumes, and other foods—bind zinc and inhibit its absorption. Thus, the bioavailability of zinc from grains and plant foods is lower than that from animal foods, although many grain- and plant-based foods are still good sources of zinc.

Clearly most people meet the recommended daily zinc intake of 11 mg for men and 8 mg for women through diet. Although I am normally not a fan of food supplements, there might be a case for using supplements containing zinc as the main ingredient for older adults and people with diseases that inhibit zinc absorption. I might even consider using a zinc supplement myself.

However, remember that high-dose zinc supplements can lead to dangerous side effects, so it’s important to stick to recommendations and only take supplements when necessary.

Does a yoghurt a day keep diabetes away?

Even if this probably is a good news story, an initial caveat is justified. Establishing a causal link between consumption of an individual food product, like yoghurt, and a specific disease is fraught with challenges. It could be a statistical anomaly or covariant factors that were responsible for the effects but not possible to be eliminated during the statistical analysis. In this study, also the authors point out that to confirm the findings controlled studies would be necessary.

With this caveat out of the way, researchers from Harvard School of Public Health found that a high intake of yoghurt seemed to be associated with an 18% lower risk of developing type 2 diabetes. If true, it shows the benefit of having yoghurt as part of a healthy diet.

Facts about the disease

Type 2 diabetes is a chronic condition that occurs when the body doesn’t produce enough insulin, or the body’s cells develop resistance to insulin. The condition has a strong genetic background and is also often associated with modifiable lifestyle risk factors like an unhealthy diet and lack of exercise. Type 2 diabetes usually develops in middle age adults but is increasingly occurring in younger age groups. The Harvard researchers pointed out that about 366 million people are affected by type 2 diabetes worldwide and it is estimated that this will increase to 552 million people by 2030, which puts pressure on global healthcare systems.

The disease develops over a long period of time with a progressive insulin resistance. As insulin is increasingly ineffective at managing the blood glucose levels, the pancreas responds by producing greater and greater amounts of insulin wearing the insulin-producing cells out. By the time someone is diagnosed with type 2 diabetes, they have lost 50 – 70% of their insulin-producing cells. This means type 2 diabetes is a combination of insulin resistance and not enough insulin.

It might be possible to significantly slow or even halt the progression of the condition by increasing the amount of physical activity and adopting a healthier diet. And here yoghurt might be a part of a healthy diet.

Facts about the study

The Harvard researchers pooled the results of three large prospective cohort studies that have been following the medical history and lifestyle habits of health professionals in the USA for different purposes. At the beginning participants had been asked to complete a questionnaire to gather baseline information on diet, lifestyle and occurrence of chronic disease. Participants were followed up every two years for 16-30 years depending on cohort with a follow-up rate of more than 90 per cent.

In this particular analysis of the cohorts results, the researchers excluded participants with diabetes, cardiovascular disease or cancer at baseline as well as lack of response to the question on dairy consumption as this was the target for the analysis. This resulted in a coverage of almost 195,000 remaining participants aged between 25 to 75 years for the analysis.

Study benefits included the large sample size, high rates of follow up and repeated assessment of dietary and lifestyle factors.

What did they find?

Within the three cohorts 15,156 cases of type 2 diabetes were identified during the follow-up period. While adjusting for chronic disease risk factors such as age and BMI as well as dietary factors, the researchers found that total dairy consumption had no association with the risk of developing type 2 diabetes. They then looked at consumption of individual dairy products, such as skimmed milk, cheese, whole milk and yoghurt and found that high consumption of yoghurt was associated with a lower risk of developing type 2 diabetes.

To confirm their results the authors conducted a meta-analysis, incorporating their results with results from a few other published studies that also investigated the association between dairy products and type 2 diabetes. Overall they concluded that consumption of one 28g serving of yoghurt per day was associated with an 18% lower risk of type 2 diabetes.

So overall some good news.

What to think of the findings?

While an 18% improvement might not sound that much every bit helps. It is extremely rare to find any food that can have a major impact on a particular health condition. What comes to mind is vitamin C rich foods like oranges that can fully protect against scurvy, but not much else. An overall healthy diet is more important than individual food components and of course yoghurt can be part of that healthy diet.

There are other support for yoghurt consumption. In 1904, four years before he jointly won the Nobel Prize in Physiology or Medicine for his research in immunology, Professor Elie Metchnikoff gave a public lecture in Paris. He suggested that beneficial healthy bacteria could be cultivated in the gut by eating yoghurt or other types of sour milk. He had surveyed 36 countries and found that more people lived to the age of 100 in Bulgaria, a high yoghurt consuming country, than anywhere else.

Later research has shown that probiotic bacteria found in yoghurt improves fat profiles and antioxidant status in people with type 2 diabetes and suggest this could have a risk-lowering effect in developing the condition.

You be the final judge, but a little yogurt every day is probably not a bad thing!

The sugar conundrum

In February 2022, EFSA published a safety assessment of sugars in the diet and their potential links to health problems. The impact of excessive sugar intake has long been a concern for health professionals, but what to do about it is not so clear. The EFSA opinion concluded that intakes of added and free sugars should be as low as possible as part of a nutritionally adequate diet, but despite reviewing about 30,000 scientific articles on the topic uncertainty remained about more specific recommendations. So not much progress.

So where do we stand?

Sugars are commonly defined as monosaccharides like glucose and fructose, both of which occur naturally in honey, many fruits, and some vegetables, and disaccharides like table sugar (sucrose, extracted from sugarcane or sugar beets) and lactose abundant in milk. Sugars are part of the carbohydrate complex of chemicals. They serve as the main energy source for the body. Carbohydrates are also components of complex molecules that perform numerous key roles in living organisms. As carbohydrates coexists with essential nutrients in many foods their consumption is inescapable. Thereby the conundrum. How to limit their consumption while achieving an adequate intake of essential nutrients.

Adding to the confusion are the different categories and sources of sugars, which can be naturally occurring or added. Total sugars comprise all mono- and disaccharides, regardless of source, including those naturally present in fruit, vegetables, and milk. Added sugars are refined sugars used in food preparation and as table sugar. Free sugars includes added sugars plus those naturally present in honey and syrups, as well as in unsweetened fruit and vegetable juices.

To date, there has been little evidence-based analysis of the scientific basis for these different sugar classifications or implications of their adoption for consumer communication and nutrition labelling.

All clear now, or not? Let’s come back to this.

Health impact of excessive sugar intake

It is clear that sugars have a negative impact on health. Consumption of sugars is a known cause of dental caries. Evidence also links excessive consumption of sugars to some chronic metabolic diseases, including obesity, non-alcoholic fatty liver disease, and type 2 diabetes.

The goal of the EFSA scientific opinion was to establish a tolerable upper intake level for dietary sugars on the basis of available data on chronic metabolic diseases, pregnancy-related endpoints and dental caries. That is the maximum level of usual daily intake of sugars from all dietary sources judged to be unlikely to pose a risk of adverse health effects to humans. A threshold should be able to be identified from the scientific literature below which no risk from consumption of dietary sugars is expected for the general population, and above which the risk of adverse health effects, including risk of disease, increases.

Current sugar intake recommendations

There have been previous attempts to establish thresholds. In 2015, major evidence-based risk assessments with quantitative recommendations for sugar intakes were published by three major independent authorities. The World Health Organization suggested an energy intake of less than 10% from free sugars with a further reduction to below 5% considered beneficial. The United Kingdom Scientific Advisory Committee on Nutrition was a bit firmer with the recommended energy intake from free sugars at 5% or less. The United States Dietary Guidelines Advisory Committee based their recommendation on an energy intake of 10% or less from added sugars.

There is thus a bit of confusion about whether recommendations should be based on free or added sugars and at what level. This variation is also apparent in recommendations from other international authorities with recommended levels of added or free sugars hovering around the 10% of energy intake. However, this is not helping consumers as none seems to base their recommendations on “total” sugars, although globally that is most commonly used for labelling and informing consumers about the sugar contents of foods and beverages.

How to solve the conundrum

So the request to EFSA for a review of the situation was certainly justified as uncertainty remained. Could the latest science help in differentiating between the health impact of added, free and total sugars? Could scientific findings point to a justification for nominating a safe threshold level? How can food labelling of sugar content assist consumers in avoiding products with excessive sugars?

In answer to the first question there was little difference in health impact between added and free sugar consumption. European data indicated that intake of fruit juices was the main difference. Others have looked at evidence linking total compared with added or free sugars with weight gain or energy intake, type 2 diabetes, and dental caries. The relations were weakest for total sugars and most consistent for dietary sources corresponding to free sugars. 

In answer to the second question it was not possible to nominate a safe threshold level based on science as there was a linear relationship between the amount of sugars consumed and its impact on health. That is the more sugar consumed the higher the risk of disease with the opposite true as well all the way down to zero consumption, given that the overall diet remained nutritionally adequate. The scientific uncertainty of potential health impact was particularly high when the intake of sugars contributed to less than 10% of energy intake.

In answer to the third question it seems we have to stick to the current Codex Alimentarius Guidelines on Nutrition Labelling, which require the labelling of total but not added or free sugars. Adoption of free sugars for labelling purposes would carry challenges related to implementation, including consumer understanding, consensus on specifications, and the current lack of analytical capabilities to differentiate between naturally occurring and added sugar.

So what should you do?

If you want to keep your sugar consumption as low as possible you can be guided by the amount of total sugar declared on the food label while considering the importance of other nutrients in the food. Don’t exclude dairy products and intact fruit and vegetables from your diet just because they naturally contain sugars. If you consume less than 50g of sugars a day you should be below the recommendation for sugars to provide less than 10% of overall energy. For reference, 50g of sugars is equivalent to about 4 tablespoons of table sugar and not as challenging as it might sound.

It can also help to keep a keen eye on food groups contributing most to the intake of added and free sugars which in European countries were table sugar, honey, syrups, confectionery and water-based sweet desserts, followed by some beverages and fine bakery wares. In infants, children and adolescents, sweetened milk and dairy products were also major contributors to mean intakes of added and free sugars.

Beneficial basil – or not!

Fruit and vegetables are important parts of the daily diet. They are low in fat, salt and sugar and a good source of dietary fibre. Fruits and vegetables contain many vitamins and minerals that are good for your health. They also importantly contain a range of exciting phytochemicals – biologically active substances that can provide protection from some diseases. Now it’s time to cover fenchol – a phytochemical found in basil.

Fenchol is a natural compound abundant in some plants including basil. It is used extensively in the perfume industry, as well as in the food processing industry. It has a smell of pine, lemon and camphor. Fenchol has many known medicinal properties, most notably antibacterial, antimicrobial, and antioxidant effects. And now there might be one more.

Gut-brain communication

A recent preclinical study by scientists at the University of South Florida Health explored interactions between the gut microbiome and the brain. Emerging evidence had indicated that short-chain fatty acid metabolites produced by beneficial gut bacteria contribute to brain health. However, the abundance of such metabolites is often reduced in older people with mild cognitive impairment and Alzheimer’s disease, but a possible association remained largely unknown.

When these gut-derived microbial metabolites travel through the blood to the brain they bind to and activate the free fatty acid receptor 2, a cell signalling receptor expressed on brain cells called neurons with a hitherto unknown effect. One hallmark pathology of Alzheimer’s disease is hardened deposits of amyloid-beta protein that clump together between nerve cells to form amyloid protein plaques in the brain. This contributes to the neuron loss and death that ultimately cause the onset of Alzheimer’s, a neurodegenerative disease characterized by loss of memory, thinking skills and other cognitive abilities.

The research findings

In step one, the new study showed for the first time that the stimulation of the free fatty acid receptor 2 can be beneficial in protecting brain cells against toxic accumulation of the amyloid-beta protein associated with Alzheimer’s disease. By blocking the receptor the scientists found an abnormal build-up of the amyloid-beta protein proving the importance of functioning receptors for sustained brain health.

In step two, the scientists performed a large-scale virtual screening of 144,000 natural compounds to find other potential candidates that could stimulate the free fatty acid receptor 2 equally well compared to the microbial metabolites. Among the leading 15 compounds, the most potent in binding to and stimulating the receptor was fenchol.

In step three, further experiments in human neuronal cell cultures, as well as worm and mouse models of Alzheimer’s disease demonstrated that fenchol significantly reduced excess amyloid-beta accumulation and death of neurons by stimulating the free fatty acid receptor 2 signalling.

Still early days

Although the intriguing preclinical findings look promising it is still early days. Before you start throwing lots of extra basil into your salad to help prevent the development of dementia, be aware that much more research is needed including in humans. A key question is whether fenchol consumed in basil itself would be more or less effective than administering the compound in a pill.

And a final caveat, if you google fenchol you will find several websites covering cannabis in which it is also present. But I would stick to basil to enhance the taste of food as well as possibly preventing the development of dementia – or not.

Time for Ginger

We have so far produced around 200 blogs covering harmful or beneficial effects of food and food ingredients but none about the potential beneficial effects of ginger. So when a team from the University of Michigan published a story about 6-gingerol, the main bioactive compound in ginger root, and its beneficial effects on certain autoimmune diseases in mice, we decided that it was time for another good news story.

A caveat though, the Michigan Medicine research covered administration of pure 6-gingerol to mice affected by lupus, a disease which attacks the body’s own immune system, and an associated condition called antiphospholipid syndrome causing blood clots. The 6-gingerol prevented neutrophil extracellular trap release, which is triggered by the autoantibodies that these diseases produce.

If it sounds complicated, be reassured that we will rather focus on more general beneficial effects of consuming ginger.

The common use of ginger root

Ginger is a flowering plant whose rhizome, ginger root, is widely used as a spice and a folk medicine. It is actually one of the first spices to have been exported from Asia, arriving in Europe with the spice trade, and was used by ancient Greeks and Romans. It belongs to the same family as turmeric and cardamom.

Ginger has a firm, striated texture. The flesh of the ginger rhizome can be yellow, white or red in colour, depending on the variety. It is covered with a brownish skin that may either be thin if harvested young or thick after mature harvesting.

Ginger has long been perceived to have anti-inflammatory and antioxidative properties and has been used traditionally as a herbal medicine for the treatment of many ailments, including chronic conditions such as asthma and arthritis. The health-promoting properties of ginger have been attributed to its richness in phenolic phytochemicals, such as gingerols and shogaols. The most abundant in fresh ginger is 6-gingerol (used in pure form in the above mentioned research) with concentrations of up to 2 mg/g in the root.

The general benefits researchers have found

Two Spanish researchers reported that ginger appears to be highly effective against nausea in people undergoing certain types of surgery. It may also help chemotherapy-related nausea. However, it may be the most effective when it comes to pregnancy-related nausea and vomiting, such as morning sickness. According to their review of 12 studies that included a total of 1,278 pregnant women, 1–1.5 grams of ginger significantly reduced symptoms of nausea in particular and to some extent also vomiting.

Chronic indigestion is characterized by recurrent pain and discomfort in the upper part of the stomach. It’s believed that delayed emptying of the stomach is a major driver of indigestion. Interestingly, ginger has been shown to speed up emptying of the stomach.

In relation to its antiemetic properties, ginger acts peripherally, within the gastrointestinal tract, by increasing the gastric tone and motility due to anticholinenergic and antiserotonergic actions. This combination of functions explains the widely accepted ability of ginger to relieve symptoms of functional gastrointestinal disorders, such as dyspepsia, abdominal pain and nausea, which is often associated with decreased gastric motility.

Ginger has been an important ingredient in Asian medicine for centuries, particularly for pain relief in musculoskeletal diseases. In a meta-analysis of five studies involving 597 patients ginger proved to be moderately effective in reducing pain and disability caused by osteoarthritis, especially affecting the knee. Osteoarthritis is a common health problem. It involves degeneration of joints, leading to symptoms such as joint pain and stiffness.

Initial findings have shown that ginger may have powerful anti-diabetic properties. In a 2015 study of 41 participants with type 2 diabetes, 2 grams of ginger powder per day lowered fasting blood sugar by 12%. It also dramatically improved hemoglobin A1c (HbA1c), a marker for long-term blood sugar levels. HbA1c was reduced by 10% over a period of 12 weeks.

Sounds like ginger should have superfood status, but note that the number of trial participants have usually been low and the doses used and the frequency of administration have varied. A word of caution might be in place, but still worth a try.

Better use ginger in moderation

If you like consuming ginger and experience beneficial effects on your health, just be sure not to overdo it. It is clear that ginger is fine in small doses, but as usual everything in moderation. Some side effects have been reported in daily doses of more than 5 grams a day, which is a lot. They include gas, heartburn and an upset stomach.

Ginger tea doesn’t seem to have serious side effects. For one thing, it would be difficult to drink enough of the tea to be exposed to anything irritating or harmful. To exceed the 5 gram limit requires quite a few cups of tea a day.

High doses of ginger may help lower blood pressure but can in turn cause some lightheadedness as a side effect. Ginger also contains salicylates, the chemical in aspirin, that acts as a blood thinner. This can cause problems for people with bleeding disorders and could interact with blood thinner medication.

Although ginger has been used throughout the world for centuries as a therapeutic agent for pregnancy-induced nausea and vomiting, a word of caution is appropriate. The best available evidence suggests that ginger is a safe and effective treatment and that possible adverse events are generally mild and infrequent. However, there is still some uncertainty regarding the maximum safe dosage and the optimal duration of treatment. Both important areas for future research.

The bottom line

It is worth repeating that too much of anything – even something as natural as ginger – is bound to cause problems. But if you’re generally in good health and you like the zest that ginger provides, drink up and don’t worry.

Just be aware that due to the global COVID-19 pandemic, ginger prices across the world have soared.

ADDENDUM:

One of my readers affected by motion sickness pointed to the beneficial effects of consuming ginger to alleviate the symptoms. This has been documented by New York Times citing research published in Lancet involving 36 people highly susceptible to motion sickness. The subjects were given either two capsules of powdered ginger, an antinausea medication or a placebo, and 20 minutes later spun on a motorised chair for up to six minutes. Ginger delayed the onset of sickness about twice as long as the medication. Half the subjects who took ginger lasted the full six minutes, compared with none of those given the placebo or the medication.

A comprehensive review of the literature on motion sickness by the US Pharmacist provided further support of the beneficial effects of ginger.

Marine biotoxins and climate change

I worry about food safety and so it seems do 60% of respondents in a global survey involving 150,000 people in 142 countries. However, while they are mostly concerned about the safety of the current food supply, I worry about the impact of climate change in worsening the food safety situation. We have already covered the impact of climate change on the accumulation of heavy metals and growth of moulds producing mycotoxins.

But of course there is more.

In this last blog in the series covering the food safety impact of climate change we will look at increases in the presence of marine biotoxins produced by blooms of harmful algae.

Toxins produced by some algal species

During recent decades, there has been an apparent increase in the occurrence of harmful algal blooms in many marine and coastal regions. Changes in climate may be creating a marine environment particularly suited to the growth of harmful species of algae. Two major functional groups of marine algae, or phytoplankton, are involved in causing toxic blooms – diatoms and dinoflagellates. There are also toxic cyanobacteria, sometimes called blue-green algae, that are not strictly speaking algae but very similar in action.

Certain toxins produced by these organisms are particularly dangerous to humans. A number of illnesses are caused by ingesting seafood contaminated by the toxins.

The most important harmful algae and their poisoning syndromes include diatoms from the genus Pseudo-nitzschia (amnesic shellfish poisoning), and species of dinoflagellates from the genera Alexandrium, Pyrodinium, and Gymnodinium (paralytic shellfish poisoning), Karenia (neurotoxic shellfish poisoning), Dinophysis and Prorocentrum (diarrhetic shellfish poisoning), and Gambierdiscus (ciguatera fish poisoning). There are also cyanobacteria that produce a range of toxins that can affect humans drinking or swimming in contaminated water causing a similar range of symptoms. Their toxins include microcystin, nodularin, cylindrospermopsin, anatoxin-a, anatoin-a(s), lyngbyatoxin and saxitoxins.

As the names of the syndromes imply the toxins can cause memory loss, digestive problems, seizures, lesions and skin irritations, and finally paralysis that may include the respiratory system. Indeed an impressive list.

Some of these toxins can be acutely lethal and are among the most powerful natural substances known. They affect fish, birds and mammals including humans. Because these toxins are tasteless, odourless, and heat and acid stable, normal screening and food preparation procedures will not prevent intoxication.

Increase in the growth of harmful algae

Dinoflagellate abundances have increased to the detriment of diatom populations in some marine ecosystems linked to increases in sea surface temperatures. This can have serious consequences.

As an example a calculation was performed of the impact of climate change on the length of the period of toxic blooms in Puget Sound, an important area of shellfish farming. Results suggested that by year 2100 the period of optimal growth of the toxic dinoflagellate Alexandrium catenella may potentially expand from 68 days to up to 259 days due to warmer water temperatures. This would have severe implications for regional food safety as A. catenella produces paralytic shellfish poisoning. It would totally close the area for shellfish harvesting for most of the year devastating the local economy.

Another example of a dinoflagellate known to generally favour warmer conditions is Gambierdiscus toxicus, one of the species producing ciguatoxin. Increases in ciguatera fish poisoning has been observed with elevated sea surface temperatures. Clinical signs in humans eating fish containing the toxin include gastrointestinal, neurologic, and cardiovascular signs. Gastrointestinal signs include vomiting, diarrhea, abdominal pain and cramps. Neurologic signs include itching, pain, visual blurring, weakness, depression and headache. Cardiovascular signs include arrhythmia, bradycardia, hypotension, and cardiac block.

Cyanobacteria can reproduce quickly in favourable conditions, where there is abundant sunlight, still or slow-flowing water and sufficient levels of nutrients, especially nitrogen and phosphorus. In still conditions, surface water may form a separate warm top layer in which cyanobacteria is able to access sunlight and nutrients. If these combined factors are present for several days, cyanobacteria multiply and form large blooms. The problem seems to be getting worse. Polluted farm runoff continues largely unabated, and the climate crisis is producing warmer weather and water temperatures, along with more rainfall – all conditions that feed the blooms. News reports of blooms in the USA have increased every year since 2010, when there were a total of 71 stories about outbreaks. In 2018 there were 452 reports about harmful outbreaks.

Incomplete understanding

As already mentioned above harmful algal blooms usually increase during the warm summer months. As daily temperatures continue to rise, the number of days ideal for harmful algal growth increases. As the planet’s oceans warm, coastal regions are seeing more and more algal blooms, often worsened by fertilizer and manure that runs off from farms. With toxic algal blooms becoming more potent and lasting longer, scientists are taking a closer look at their links to a changing climate. What was once considered a summertime matter is now being considered a year-round issue.

However, the extent to which regional climate change will influence harmful algal bloom dynamics is uncertain as separating the effects of climate change from natural variability remains a key scientific challenge. Climate change pressures will influence marine planktonic systems globally, and it is conceivable that harmful algal blooms may increase in frequency and severity. Nonetheless there is only basic information to speculate upon in which regions or habitats harmful algae may be the most resilient or susceptible. 

We can continue to test for the presence of toxins in seafood as is currently the practice in many countries. But the potential escalation of outbreaks could easily overwhelm the system. Should we risk it? I for one worry about the future given the current trajectory of global warming.

Health benefits of pickled capers

If you like to spice your food with capers you may be in luck. Capers are the immature flower buds of the caper bush, Capparis spinosa, growing naturally in the Mediterranean and parts of Asia and Africa. Capers are harvested early in the morning before the heat opens the flower bud. There are also the caper berries, the resulting fruit picked much later in the season.

Archaeological evidence for human caper consumption dates back as far as 10,000 years, according to archaeological findings from Mesolithic soil deposits in Syria and late Stone Age cave dwellings in Greece and Israel.

Multiple health benefits proposed

Pickled capers are common in Mediterranean cuisine, where they provide a salty tang and decorative flair to a variety of meats, salads, pastas and other foods. Apart from the culinary benefits, capers may also have beneficial health effects. Too good to be true, read on and all will be revealed.

Actually, capers have traditionally been used as a folk medicine for hundreds if not thousands of years. True or false, it has been proposed that capers have anti-bacterial, anti-carcinogenic, analgesic, and anti-inflammatory properties. It has also been suggested that capers might strengthen capillaries and inhibits platelet clump formation in blood vessels, relieve rheumatic pain and act as an appetite stimulant. Sounds like a bit much. However, evidence for their efficacy is in some cases supported by clinical findings but as it is often purely anecdotal we need more proof.

Let’s untangle this a bit

It is well known that capers are rich in flavonoid compounds including rutin and quercetin. During the common pickling process of the capers, rutin is further converted to quercetin. This makes pickled capers the richest natural source of quercetin with reported maximum concentrations of 520 mg/100 g. Mechanistically, quercetin has been shown to exert antioxidant, anti-inflammatory, and anticancer activities in a number of cellular and animal models, as well as in humans through modulating the signalling pathways and gene expression involved in these processes.

And now new research from the University of California, Irvine School of Medicine has found that quercetin activates proteins required for normal human brain and heart activity. Specifically, the researchers discovered that quercetin modulates potassium ion channels in the KCNQ gene family. These channels are highly influential in human health and their dysfunction is linked to several common human diseases, including diabetes, cardiac arrhythmia, and epilepsy.

The study revealed that quercetin modulates the KCNQ channels by directly regulating how they sense electrical activity in the cell. In doing so, it tricks the channel into opening when it would normally be closed. Increasing the activity of KCNQ channels in different parts of the body is potentially highly beneficial, suggesting a previously unexpected mechanism for the therapeutic properties of capers.

Alternative sources of quercetin

So now we know that capers are actually good for our health. Capers are also low in calories and high in vitamins and minerals. Unfortunately, they are also high in salt thanks to the way they’re preserved. As they’re bitter on their own, capers are stored in brine or packed in salt. If you’re watching your salt intake that’s worth bearing in mind.

However, don’t despair as there are alternative sources of quercetin. It is found in many fruits, vegetables, leaves, seeds, and grains. Red onions and kale are common foods containing appreciable amounts of quercetin.

So you just have to dig in.