Zinc

Zinc is an important part of our diet. It is found in meat, shellfish, dairy and some cereals. Most people get enough from a balanced diet.

Zinc is pivotal in would healing, keeping the protective skin barrier intact, and supporting the function of white blood cells.

Woman need about 7mg a day, men need about 9.5mg. Too much zinc can reduce copper absorption by the body, carrying a risk of anaemia and osteoporosis, so if you choose a supplement, stick to a maximum of 25mg per day.

It has been suggested that zinc can reduce the ability of some viruses to multiply, so there have been many studies looking at the effect of zinc lozenges on both preventing and treating the common cold. While results have been conflicting (partly due to uncertainty about the dose and type of lozenge) there is some evidence that they might speed recovery from colds.

It is still too early for reliable studies into its effect on the coronavirus, though it is possible that it might inhibit the action of some viruses.

Source: Health column in Good Housekeeping, June 2020.

Covid-19 Who is most at risk?

Who is most at risk?

Adults over the age of 60.

Age is one factor in whether someone dies from Covid-19. This is because past the age of 60, someone is more likely to have heart disease, cancers and other medical conditions such as diabetes, which mean the body is less able to fight off the infection. The proportion of Covid-19 deaths by age groups is:

• 90% are over 60. (52% are over 80 and 39.7% are between 60 and 79.)
• 7% are between 40 and 59, while 0.72% are between 20 and 39
• 0.077% are between 0 and 19.

Very few children become severely ill with the virus

Children of all ages may catch the disease but are likely to have milder symptoms and a lower chance of severe disease than adults. They are also less likely to pass on the infection. Australian researchers have identified a number of factors which may explain this.

• Children have strong undamaged cells in their blood vessels which prevent inflamation and clotting, and their blood clotting system is different.
• They have elevated levels of vitamin D.
• Their immune system is fast acting. They are more likely to be infected with other pathogens such as colds and and other germs picked up in the playground. This can build a strong natural immune system.
• They have often been recently vaccinated for other diseases, including MMR. This effectively 'trains' the immune system and keeps it 'firing on all cylinders'.
• They have fewer ACE2 receptors, which the virus uses to infect cells. ACE2 becomes more prevalent as they grow up.

However a coronavirus-related inflammatory syndrome occasionally occurs in children. Symptoms include high temperature, low blood pressure, a rash and difficulty breathing; some also had tummy pain, vomiting or diarrhoea, and inflammation of the heart and abnormal blood test results. Experts say these are signs the body becomes overwhelmed as it tries to fight of the infection.

People who are overweight or obese.

Obesity increases the risk of a number of diseases, (e.g. heart disease, cancer and type 2 diabetes). The more overweight, the more fat you carry, the less fit you are and the lower your lung capacity. So it's a bigger struggle to get oxygen into the blood and around the body, which impacts on the heart and blood flow. Being overweight, you also have a demand for more oxygen. This can be a serious problem during a respiratory infection like coronavirus; the obese body  becomes overwhelmed by the lack of oxygen. Overweight and obese people in intensive care are more likely to need assistance with breathing and support with kidney function.

An enzyme called ACE2, present in cells, is the main way for the virus to enter the body. Higher levels of this are thought to be found in adipose (fatty) tissue, which could explain the higher risk of catching the disease and a higher risk of being ill with it.

The ability of the body to fight off the virus (the immune response) is not as good in people who are obese, due the inflammation driven by immune cells called macrophages which invade our fat tissue; they interfere with how our cells respond to infection. This can lead to a 'cytokine storm' - a potentially life-threatening over-reaction of the body's immune system which causes inflammation and serious harm.

And there can be challenges in managing these patients in intensive care: (a) it is more difficult to intubate them (put onto a ventilator); (b) to scan them because of weight limits and (c) they may be more tricky to turn, or prone, in order to relieve their breathing.

Men

Men are slightly more likely to die, but in some countries this is may be due to higher smoking rates in men which compromise lung function. New research shows that men have higher levels of the ACE2 receptor on cell surfaces, which binds to the new virus, allowing it to enter and infect cells. Men have a higher level of ACE2 found in the heart, kidneys and tissues lining blood vessels, and especially high levels in the testes. 

Black, Asian and Minority Ethnic (BAME) populations 

UK data (May 2020) suggests that 35% of critically ill patients are from BAME backgrounds. The following factors appear to be important.

Many BAME populations come from lower socioeconomic backgrounds and work in public-facing occupations (healthcare, cleaners, restaurant workers, transport and delivery workers and other public services). They are likely to be in inter-generational households, with more of the aged still at home, and religious activities with large numbers of attendees. Between 15% and 30% live in overcrowded households in contrast to just 2% of white British households.

They have an increased risk of certain diseases (e.g. diabetes and heart disease).  People from BAME backgrounds have more of a specific type of fat tissue which is prone to macrophage invasion (see section on obesity and the ACE enzyme), have elevated rates of diabetes, and may therefore be more vulnerable to the virus.

Pregnant women

Pregnant women may be at higher risk for severe infection but data is not yet available. 
Those with a pre-existing condition (e.g. high blood pressure, diabetes, heart disease and lung disease) are more likely to die.

People with disabilities that limit activity.

People (over the age of 9) with a disability that limits activity account for nearly 60% of UK Covid-19 deaths, but form only 16% of the population. (Study reported 18 Sept. 2020.)

Certain blood groups may be more likely to have severe infections

Ethnic and national populations can have different proportions of blood groups. Worldwide the rarest blood type is AB, while Rh negative blood types are found in 0.3% of Asian populations and 15% of European populations. Proportions can also differ within a country. In the UK, the ratio is O = 48%   A = 38%   B = 10%   AB = 3%. In southern England: O = 44%   A = 45%   B =  8%    AB = 3%.

A study in China (March 2020) found that the normal population ratio was A = 31%   B = 24%   AB = 9%   O = 34%, while the ratio for those with the virus was A = 38%   B = 26%  AB = 10%  O = 25%.  Researchers concluded that "blood group A had a significantly higher risk for Covid-19 compared with non-A groups, whereas blood group O had a significantly lower risk." (Their findings were published before peer review, so need to be treated with caution.) In the US, another study found a similar pattern but only among rhesus positive patients. NB. Susceptibility to infection does not necessarily equal risk to getting seriously ill. Other studies on infection rates and severity of illness relating to blood groups are currently in progress in several countries.

Another study of patients in Italy and Spain with Covid-19 respiratory failure found two genetic variants associated with the severity of their disease. One cluster of six genes had included genes that regulate ACE2. The other variant was the ABO blood group system. However, an analysis of medical data from thousands of people in the Boston area of the US found no association.

Note: Some other viruses are blood-group dependent. People with type A blood seem to be more susceptible to hepatitis B and HIV, while people with type O are somewhat protected against catching SARS.

END

 

Covid-19 Diagnosis

Covid-19 Diagnosis

Have I got the virus?

The standard test uses a nasal swab (which can be self-administered) or a nose/throat area swab (done by trained healthcare workers). Current tests are thought to have up to 30% false negatives.

A study indicates that saliva collection may be easier to use and collects more viral material. The false negative rate appears to be better too (only 12%). Still to be confirmed by other studies.

Have I had the virus?

Antigen tests (which identify someone has had the infection) use a blood sample. These are still in development.

END 

Managing Human Hunger Appetites

Studies over a 30 year period have discovered new facts about human nutrition, that changes how we understand appetite, explains the obesity epidemic and suggests a way to solve that. Here are the main points of their theory.

Appetite balancing is common across the animal kingdom, including slime molds, cockroaches, spiders, cats, dogs, mink and non-human primates. Some species turn out to have two appetites. Others have five appetites for specific nutritional requirements: three for the main macro-nutrients (protein, carbohydrates and fat) and two for specific micro-nutrients (sodium and calcium).

If a species were to have a separate appetite for each necessary nutrient, they would need complex biological  systems. Species have evolved to focus on the nutrients that are needed in very specific quantities. For other things, natural diets were rich enough for them to automatically get enough of the other nutrients needed. In a food environment that is poor in one of the essential nutrients, individuals will eat more of other items in order to keep up the calorie requirements.

Humans are among the five appetite species. People typically need 15% to 20% of daily calories from protein. It turns out that humans are living in a protein dilute, energy-rich environment. Between 1961 and 2000, the proportion of protein in an average US diet fell from 14% to 12.5%, with the balance made up fats and carbohydrates.That shift was the only way people could maintain target protein consumption was to increase total calories intake by 13% - more than enough to create an obesity epidemic.

Experiments have shown that most of the extra calories eaten by those on a low protein diet came from savoury snacks, especially those tasting of umami, the signature flavour of protein. The protein-deprived were craving things that tasted of protein, even though composed of carbohydrates.

Ultra-processed foods are designed to be irresistable, and tend to be low in protein (expensive) and high in cheap carbs and fats. Such foods include pizzas, crisps, breakfast cereals, sweets, bread, cakes, mayonnaise, ketchup and ice cream, items which make up more than half of a typical US and UK diet - with some people eating these almost to the exclusion of everything else.

Our appetite for protein is stronger than our ability to limit carb and fat intake, so when protein is scarce, our appetite for it overwhelms the mechanisms that normally tell us to stop eating fats and carbs. Ultra-processed foods also contain very little fibre, which is filling and puts a brake on our intake.

How to manage your appetites

1. Calculate your protein target by looking up the daily energy requirement for your age, sex and level of activity. (This is can be done with the Harris Benedict equation calculator, available on many websites).
2. Work our the proportion that should come from protein by multiplying that figure by 0.15 (to give the 15% of energy from protein). Depending on age, you might need to use the multiplier of 0.18 (for 18% needed by 18 to 30 year olds), 0.17 (for the 17% needed by those in their 30s, or 0.2 (for those over 65 who need 65%).
3. Divide the resulting number by 4 to get the number of grams of protein a day you should eat. ( gram of protein contains 4 kilocaolories of energy.)
4. Then work out how to obtain that protein from protein-rich foods such as meat, fish, eggs, dairy, pulses, nuts and seeds. The protein content is often listed on food labels, or available online.
5. If you eat this amount of protein, it will satisfy your protein appetite and automatically ensure you don't overeat carbs and fats you won't need to track these at all).
6. Make sure you supplement the high-protein foods with mostly wholefoods, mainly plant-based, which will also supply your fibre needs.
7. Most importantly, avoid ultra-processed foods by keeping them out of the house.

Source: article: In perfect balance by David Raubenheimer and Stephen Simpson, New Scientist 23 May 2020.

Adolescent and Lifetime Offenders

Long-term research into male anti-social behaviour indicates that it is concentrated in adolescence, with fewer than 10% of males committing more than 50% of crimes. The offenders fall into two groups in adulthood, lifetime offenders and adolescent delinquents. A third group never offend.

Life-course persistent offenders (LCPO). Show extreme/violent anti-social behaviour from early childhood and on into adulthood. Brain scans show that LCPO individuals have less grey matter in some regions of the cortex, most of which are linked to anti-social behaviour (goal-directed behaviour, regulation of emotions and motivation). Possible causes are: (a) born with brain structure abnormalities, (b) bad childhoods or (c) both of these.

Most people with a low polygenic score for educational achievement have a lifelong struggle with self-control.They also tend to be late talking, don't use language very well, have difficulty learning to read, trouble concentrating and controlling thoughts, and struggle to remember facts and figures. This means that they find school frustrating and humiliating, and leave as soon as they can. A lack of qualifications leads to difficulty finding a job, and turning to a life of crime (and if good at it, brings self-esteem). LCPO are still locked up to keep the public safe.

Adolescent limited delinquents (ALD). Show a similar level of anti-social behaviour at around 18 but grow out of it. Deprivation, abuse and neglect allow vulnerability grow into anti-social/criminal behaviour. Many adolescents feel the need to prove themselves as adults and commit risky crimes, but once entered into adulthood, this lifestyle loses its appeal.

It is easy to walk away from offending if you have avoided having a criminal record. UK policy therefore tries to divert away from courts and jails, using approaches that aim to contain and change their behaviour without bringing formal charges.

Not-offending (NO). These individuals never commit anti-social behaviour. They simply don't want to break the law and adolescent culture no longer sees them as outcasts (the 'goody-goody' ones).

What we need to do.

• Develop treatments and rehabilitation protocols rather than invest in new prisons. 
• Effective prevention programmes need to start in early childhood. 

Source: Crime and punishment article in New Scientist by Terri Moffitt, King's College, London (July 2020)