Alcohol and brain function in old age

Let’s get this out of the way at the start. It is clear that alcohol misuse is a leading cause of morbidity and mortality. As an example, binge drinking has been shown to lead to a higher risk of cardiovascular disease.

But what about lower level alcohol consumption?

Some previous studies have reported that low to moderate alcohol consumption show benefits to cognitive function. However, others have found no, minimal, or even adverse effects associated with alcohol consumption.

So what to believe?

Association studies are difficult to interpret correctly as most effects studied are multifactorial and vary over time. In particular, a one time measurement can easily be misleading as the time factor is disregarded.

To overcome this challenge, a study published in June 2020 by researchers from the University of Georgia used repeated measurements of health and lifestyle, including questions on drinking habits, in a group of almost 20,000 middle-aged and older participants over a ten-year period.

The participants had their cognitive function measured in a series of tests looking at their overall mental status, word recall and vocabulary. The test results were combined to form a total cognitive score.

And the good news – light to moderate drinking may preserve brain function in older age.

Compared to nondrinkers, those who had a drink or two a day tended to perform better on cognitive tests over time. The optimal amount of drinks per week was between 10 and 14 drinks.

Even when other important factors known to impact cognition such as age, smoking or education level were controlled for, they saw a pattern of light drinking associated with better cognitive function.

The debate will continue

The debate is clearly not over about potential benefits of moderate alcohol consumption. We have written about the balance of the good and bad of alcohol consumption before.

For a while it looked like the fact that regular, moderate alcohol consumption had been shown to promote heart health was settled. And then came another review of previously published research questioning this conclusion.

Several studies pointed to similar protective benefits of moderate alcohol consumption for brain health. And then a systematic review of existing literature on alcohol consumption concluded that there seemed to be no safe level of drinking alcohol.

Believe what you will, but at my age I will cling to the latest findings as it seems to be a solid design of the study.

The benefits of red onions

During the current doom and gloom we need to be cheered up with some positive news. And should you read this when a vaccine has disarmed the coronavirus causing the COVID-19 pandemic in 2020 and governments around the world have taken the necessary actions to limit global warming to 1.5ºC, well, you might still appreciate some good news. 

So here goes.

Multiple health benefits

The next time you go shopping you might reach for red onions. Onions belong to the Allium family of plants, which also includes chives, garlic, and leeks. Farmers have cultivated Allium vegetables for millennia. These vegetables have characteristic pungent flavours and some beneficial medicinal properties. The benefits among many include a reduction of the risk of several types of cancer, improving mood, and maintaining skin and hair health.

Looking back in time, ancient medical texts from Egypt, Greece, Rome, China, and India all cite therapeutic applications for Allium vegetables.

Contemporary studies confirm the early findings. One review from 2015 found a general relationship between an increased consumption of Allium vegetables and a reduced risk of cancer, especially cancers of the stomach and gastrointestinal tract.

Such a relationship was further supported by a 2019 Chinese study that compared 833 people with colorectal cancer with 833 people who did not have the disease. The researchers found that the risk of colorectal cancer was 79% lower in those who regularly consumed Allium vegetables, such as onions.

Experts do not fully understand the exact mechanism by which some compounds in onions inhibit cancer. There are compounds called organosulfurs in onions, some of which have been shown to suppress aspects of tumour growth. However, further research is necessary to confirm which compounds in onion have protective effects against cancer.

But there is more

A wide range of further beneficial effects have also been proven. Different biological properties, such as antioxidant, antimicrobial and anti-diabetic activities, have been reported.

Not surprising as onions are nutrient-dense. One medium onion has just 44 calories but delivers a considerable dose of vitamins, minerals and fibre.

As a good source of vitamin C, onions may support the building and maintenance of collagen. Collagen provides structure to skin and hair.

A 2014 review found that among various activities of Allium vegetables, regulation of hypoglycaemic activity is considered important in helping to control diabetes. Sulfur compounds including S-methylcysteine and flavonoids such as quercetin are mainly responsible for the hypoglycaemic activity. S-methylcysteine and flavonoids help to decrease the levels of blood glucose, serum lipids, oxidative stress and lipid peroxidation, as well as increasing antioxidant enzyme activity and insulin secretion. 

2019 review found that quercetin, a compound in onion skin, had links to lower blood pressure when the researchers extracted it and administered it as a supplement.

Somewhat surprisingly onions have been shown to be able to fight potentially dangerous bacteria, such as Escherichia coliPseudomonas aeruginosaStaphylococcus aureus and Bacillus cereus.

Onions are also rich in B vitamins, including folate (B9) and pyridoxine (B6) playing key roles in metabolism, red blood cell production and nerve function.

Lastly, they’re a good source of potassium, a mineral in which many people are lacking.

I hope you’re convinced by now.

So why red onions?

Any Allium vegetable would do but there is something special with the red colour of red onions.

A Canadian study revealed that the red onion not only has high levels of quercetin, but also high amounts of anthocyanin, which enriches the scavenging properties of quercetin molecules. Anthocyanin is instrumental in providing colour to fruits and vegetables so it makes sense that the red onions, which are darkest in colour, would have the most cancer-fighting power.

There are plenty more benefits associated with Allium vegetables, but this is it for now as I’m off to buy some red onions.

Mycotoxins in a Changing Climate

Global climate change is an issue we should take very seriously now or it will threaten our future food supply. However, I am writing this in June 2020 in the middle of the coronavirus pandemic that is attracting all the attention. There are so far more than 6 million people affected worldwide and soon more than 400,000 deaths.

Most countries, but not all, have reacted with urgency to the acute situation with people movements severely restricted and huge amounts of money spent to support economies. More than one hundred attempts to develop vaccines agains the COVID-19 disease are under way to prevent future outbreaks.

Willingness to limit climate change lacking

We already have the “vaccines” or knowhow to prevent further escalation of the changing climate. Although climate change in the longer term will threaten food security, that is global access to food, and negatively impact food safety with the potential to cause much more pain and suffering, hunger and deaths, it is not getting the same attention as a novel acute disease.

There are many pathways through which climate related factors may impact food safety including: changes in temperature and precipitation patterns, increased frequency and intensity of extreme weather events, ocean warming, and changes in the transport pathways of complex contaminants.

Food security might be the more serious challenge as sufficient access to nutritious food is already an issue in many parts of the world, but long-term quality of life is also threatened by food contamination. We have already covered accumulation of arsenic as an example of heavy metal increases in food caused by climate change. Here we will cover aflatoxin as an example of an increased threat from a range of mycotoxins as fungal growth is influenced by climate change.

Mycotoxin threat will increase

Mycotoxins are compounds naturally produced by a large variety of fungi (moulds) that can cause acute effects, including death, along with chronic illnesses from long-term exposure, including various forms of cancer. It has been estimated that 25% of the world’s yearly crop production is already contaminated with mycotoxins. Mycotoxins are known to occur more frequently in areas with a hot and humid climate.

Aflatoxins, which have the highest acute and chronic toxicity of all mycotoxins, assume particular importance. Aflatoxin produced by Aspergillus flavus and A. parasiticus is a genotoxic carcinogen, but is also a potent acute toxin, and is widely distributed associated especially with maize, groundnuts, tree nuts, figs, dates and certain oil seeds such as cottonseed.

Aflatoxins are a group of approximately 20 related fungal metabolites. They are heat stable and difficult to destroy during processing. Thus exposure, both acute and chronic, can have significant impacts on vulnerable groups, especially babies and children. Four aflatoxins – B1, B2, G1 and G2 – are particularly dangerous to humans and animals.

Health effects of aflatoxin exposure

Outbreaks of acute aflatoxicosis were reported in Kenya in 2004 with 125 deaths resulting from consumption of aflatoxin contaminated maize with repeated events in 2005 and 2006. Most recently several deaths attributed to aflatoxins were reported during the summer of 2016 in the United Republic of Tanzania.

However, chronic effects are much more common. Hepatocellular carcinoma, or liver cancer, is the third leading cause of cancer deaths worldwide, with prevalence 16-32 times higher in developing countries than in developed countries. Of the 550,000-600,000 new cases worldwide each year, about 25,000-155,000 may be attributable to aflatoxin exposure. Most cases occur in sub-Saharan Africa, Southeast Asia, and China with largely uncontrolled aflatoxin exposure in food.

The geographical areas subject to aflatoxin growth in maize and wheat are expected to change with temperature increases – it is predicted that aflatoxin contamination and the associated food safety issues will become prevalent in Europe with a temperature increase of +2°C.

Changes in contamination patterns

Aflatoxin contamination causes significant loss for farmers, businesses, and consumers of varied susceptible crops. Climate change alters the complex communities of aflatoxin-producing fungi. This includes changes in space, time and in the quantity of aflatoxin-producers. Generally, if the temperature increases in cool or temperate climates, the respective countries may become more susceptible to aflatoxins. However, tropical countries may become too inhospitable for conventional fungal growth and mycotoxin production.

Although some regions can afford to control the environment of storage facilities to minimize post-harvest problems, this happens at high additional cost.

Many industries frequently affected by aflatoxin contamination know from experience and anecdote that fluctuations in climate impact the extent of contamination. Climate influences contamination, in part, by direct effects on the causative fungi. As climate shifts, so do the complex communities of aflatoxin-producing fungi. This includes changes in the quantity of aflatoxin-producers in the environment and alterations to fungal community structure.

Fluctuations in climate also influence predisposition of hosts to contamination by altering crop development and by affecting insects that create wounds on which aflatoxin-producers proliferate. Aflatoxin contamination is prevalent both in warm humid climates and in irrigated hot deserts. In temperate regions, contamination may be severe during drought.

Public health threat

As usual prevention is much better than late action to repair already existing damage. This is especially important in at risk regions such as parts of Africa and Asia where the risks of exposure to mycotoxins may increase under predicted climate change conditions.

The combination of future food scarcity and contamination of a larger part of the food supply has the potential of creating an explosive public health threat.

Climate change and food safety

 

global-warming1What has global climate change to do with food safety you ask? Well quite a lot is the unfortunate answer. In a previous blog we have already described the increased risk of finding toxic levels of arsenic in rice due to global warming. Not convinced yet? Maybe the following quotes from a range of official global organisations can provide some compelling information for you to change your mind.

Opinions expressed by some official agencies

The world Health Organization (WHO) writes:

Climate change is likely to have considerable impacts on food safety, both direct and indirect, placing public health at risk. With changing rainfall patterns and increases in extreme weather events and the annual average temperature we will begin to face the impacts of climate change. These impacts will affect the persistence and occurrence of bacteria, viruses, parasites, harmful algae, fungi and their vectors, and the patterns of their corresponding foodborne diseases and risk of toxic contamination. Alongside these impacts, chemical residues of pesticides and veterinary medicines in plant and animal products will be affected by changes in pest pressure. The risk of food contamination with heavy metals and persistent organic pollutants following changes in crop varieties cultivated, cultivation methods, soils, redistribution of sediments and long-range atmospheric transport, is increased because of climate changes.

The European Food Safety Authority (EFSA) writes:

Climate change poses significant challenges to global food safety. Long-term changes in temperature, humidity, rainfall patterns and the frequency of extreme weather events are already affecting farming practices, crop production and the nutritional quality of food crops. The sensitivity of germs, potentially toxin-producing microorganisms and other pests to climate factors suggests that climate change has the potential of affecting the occurrence and intensity of some foodborne diseases. Also, changing conditions may favour the establishment of invasive alien species harmful to plant and animal health. Surface seawater warming and increased nutrients input leads to the profusion of toxin-producing algae causing outbreaks of seafood contamination.

The transmission of infections or diseases between animals and humans (“zoonotic diseases”) is a major source of food safety risks. Environmental factors such as temperature, rainfall, humidity levels and soil can help to explain the distribution and survival of bacteria.

The European Food Information Council (EUFIC) writes:

There is a growing consensus that human activities may be changing our planet’s climate. These changes in climate have a number of possible implications for human health and welfare, one of which could be the safety of food.

It is impossible to accurately assess the full impact of climate change on food safety. However, it is likely that some effect on microbiological and chemical hazards will be seen. The extent of the risk posed by these hazards will depend on the type of hazard and the local conditions and practices.

The Food and Agriculture Organization (FAO) writes:

Climate change does not only imply increased average global temperature. Other effects of climate change include trends towards stronger storm systems, increased frequency of heavy precipitation events and extended dry periods. The contraction of the Greenland ice sheet will lead to rising sea-levels.

These changes have implications for food production, food security and food safety. It is widely understood that the risks of global climate change occurring as a consequence of human behaviour are inequitably distributed, since most of the actions causing climate change originate from the developed world, but the less developed world is likely to bear the brunt of the public health burden.

There is reason to believe that climate change can affect infection of crops with toxigenic fungi, the growth of these fungi and the production of mycotoxins. Given the great importance of this hazard, it is necessary that we understand what changes we might expect in order to better prepare ourselves to deal with this critically important issue.

Changes in climate may be creating a marine environment particularly suited to the growth of toxic-forming species of algae. Toxin-producing algal species are particularly dangerous to humans. A number of human illnesses are caused by ingesting seafood (primarily shellfish) contaminated with natural toxins produced algae; these include amnesic shellfish poisoning (ASP), diarrheic shellfish poisoning (DSP), neurotoxic shellfish poisoning (NSP), azaspiracid shellfish poisoning (AZP), paralytic shellfish poisoning (PSP), and ciguatera fish poisoning. These toxins may cause respiratory and digestive problems, memory loss, seizures, lesions and skin irritation, or even fatalities in fish, birds, and mammals (including humans).

Like EFSA, FAO also comments on zoonotic diseases such a hot topic with COVID-19 a prescient example:

Climate change is one of several ‘global change’ factors driving the emergence and spread of diseases in livestock and the transfer of pathogens from animals to humans.

The United States Environmental Protection Agency (EPA) writes:

Climate change will have a variety of impacts that may increase the risk of exposure to chemical contaminants in food. For example, higher sea surface temperatures will lead to higher mercury concentrations in seafood, and increases in extreme weather events will introduce contaminants into the food chain through stormwater runoff.

The United States Department of Agriculture (USDA) writes:

The assessment finds that climate change is likely to diminish continued progress on global food security through production disruptions leading to local availability limitations and price increases, interrupted transport conduits, and diminished food safety, among other causes. The risks are greatest for the global poor and in tropical regions. In the near term, some high-latitude production export regions may benefit from changes in climate.

A bleak future

As you can see a fairly bleak uniform view from many official agencies. Global efforts to reduce greenhouse emissions and regional measures to adapt to changing climatic conditions will be important to mitigate the impact on food and feed safety in relation to human health and nutrition, animal and plant health, and the environment.

The previous blog on arsenic was used as an example of a an increasing human health problem of a contaminant due to climate change. In some future blogs we will cover the the increased prevalence of algal and fungal toxins due to global warming.

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.