Sunday, 29 May 2022

Mutations and the risk of cancer

 A new study carried out by the the Wellcome Trust Sanger Institute sheds new light on the role of genetic changes in ageing and cancer. By comparing the accumulation of mutations across many animal species, researchers found that despite a huge variation in lifespan and size, different animal species end their natural life with similar numbers of genetic changes.

The study (published 13 April 2022 in Nature) analysed genomes from 16 species of mammal, from mice to giraffes. The analyses confirmed that the longer the lifespan of a species, the slower the rate at which mutations occur, lending support to the theory that somatic mutations play a role in ageing.

Somatic mutations are genetic changes that occur in all cells throughout the life of an organism. In this natural process, in humans cells acquire around 20 to 50 mutations per year. Most of these are harmless, but some can start the process of developing cancer or impairing the normal functioning of a cell. 

Since the 1950s there has been speculation that these mutations may play a role in ageing, but it is only now with technology able to observe genetic changes in normal tissue that research can start to answer whether this is the case.

Peto's paradox. Since cancers develop from single cells, species with larger bodies (and therefore more cells) were thought to have a higher risk of cancer. But cancer incidence across animal species is independent of body size. Large bodied animal species are thought to have evolved mechanisms to prevent cancer but until now this has not been tested.

The Wellcome Sanger Institute study used new methods to measure somatic mutation in 16 mammalian species with a wide range of lifespans and body sizes, including human, mouse, lion, giraffe, tiger and the long-lived and highly cancer resistant naked mole-rat. Mutation rates were measured in intestinal stem cells. Analysis of the patterns of mutations indicated that somatic mutations accumulated linearly over time, and were caused by similar mechanisms across all species, including humans, despite different diets and life histories. Also the rate of somatic mutation decreased as the lifespan of each species increased. Researchers now want to study further diverse species, including insects and plants.

Peto's paradox still needs an answer, since after accounting for lifespan, researchers found no significant link between somatic mutation rate and body mass, indicating that other factors must be involved as well. It does not seem that evolution has chosen a single way of controlling the incidence of cancer, but that it is possible that every time a species evolves a larger size than its ancestors, evolution might use a different solution to the problem.

On average a giraffe is 40,000 times bigger than a mouse, and a human lives 30 times longer, but the difference in the number of somatic mutations per cell at the end of lifespan between the three species only varied by around a factor of three.

The exact causes of ageing remain unsolved, though it is likely to be caused by the accumulation of multiple types of damage to cells and tissues throughout life, including somatic mutations, protein aggregation and epigenetic changes.

Source: Mutations across animal kingdom shed new light on ageing in Science Daily, 13th April 2022.


Sunday, 8 May 2022

What Time of Day to Take Vitamins

 Nearly half the UK population take vitamin supplements, but experts say when and how you take them changes how effective they are.

Iron: Around three-quarters of women are at risk of iron-deficiency anaemia, mainly due to iron loss during their monthly periods.

  • Take on an empty stomach an hour before bed (and two hours after supper) and combine it with vitamin C or A.
  • Vitamin C can help your body absorb iron as it bonds to iron particles, helping them to dissolve more completely in the gut. Vitamin A can also improve iron absorption.
  • Look for iron supplements that contain vitamin A, or its precursor beta-carotene.
  • Take iron supplements on alternate days, as a 2017 study found that more iron is absorbed taken this way.
  • Avoid taking with dairy, tea or zinc pills. Certain foods, especially dairy - including milk-based drinks, can block iron absorption. And since tea sipped with a meal can inhibit the absorption of iron by up to 90%, take your iron pill with water. And zinc competes with iron because both minerals need to attach to the same 'transporter molecules' in the gut.

Calcium: Many menopausal women take calcium to help prevent the bone-thinning disease osteoporosis. Calcium is often combined in a pill with magnesium, which is also good for bones.

  • Take a supplement (ideally also containing magnesium, vitamin D and vitamin K) with food.
  •  Taking calcium with food will also enhance absorption. Look for products with calcium citrate, which is better absorbed than calcium carbonate.
  • Avoid taking with zinc or iron pills.
Vitamin D: In the winter months, around half the UK population is low in vitamin D, a nutrient vital for healthy bones and strong immunity. This is because we make vitamin D via sun exposure on our skin.
  • Take 10mcg during the winter, in the evening with food (or largest meal of the day) containing fat.
  • Vitamin D is better absorbed if taken with a meal that contains some fat, such as avocado, egg yolks or olive oil.
  • Avoid taking with vitamin E pills; as both are absorbed in the same way.
Vitamin C: Important for the immune system and vital for healthy skin and bones. It is a water soluble nutrient that we can absorb in doses of up to 400 mg. Any excess above this is not stored by the body, but passed out in urine.
  • Take in the morning on an empty stomach. 
  • If taking doses larger than 400 mg (e.g. during a cold), split these throughout the day. 
  • A standard supplement will give you more than enough vitamin C so no need to take liposome-encapsulated products.
  • Best absorbed on a completely empty stomach, e.g. before breakfast, as absorption can be hindered by proteins and fibre in food.
Fish oil: A rich source of two omega-3 fats (EPA and DHA) that have proven benefits for a wide range of illnesses including low mood, heart disease and rheumatoid arthritis.
  • Take with food that contains fat, which triggers the pancreas to release enzymes that help break down the omega-3 oils into fragments small enough to be absorbed through the gut wall.
  • Avoid taking before a workout or sleep to avoid unpleasant fishy burps.
B vitamins: The group of eight B vitamins (including B6, B9 (folic acid), and B12 are vital for healthy blood, nerve function and energy levels. They are water-soluble.
  • Take first thing in the morning on an empty stomach. Choose a supplement with a blend of different B vitamins.
  • Take a blend of B vitamins. Taking folic acid alone can trigger or mask a deficiency in vitamin B12.
  • Avoid taking last thing at night as high vitamin B6 doses can interfere with sleep. Avoid taking with food, as vitamin B12, in particular, binds to the food we eat and can then end up passing straight out of the gut as waste without being absorbed.
Probiotics: These are 'good bacteria' that make up part of our gut microbiome - the community of bacteria that plays a vital role in our digestive health and immune system. A poor diet or medication such as antibiotics can kill off good bacteria, helping bad ones to survive, increasing the risk of gut infections or digestion problems. Probiotic supplements aim to replenish levels of good bacteria. As they are live bacteria, they need to reach the gut intact.
  • Take: half an hour before eating. Take before a meal containing some fat. 
  • Avoid: taking with hot drinks, juices or alcohol.
Magnesium: Useful for bone health. 
  • Take: if using alone for a relaxing effect, take at bedtime.
  • Take care: If you take calcium, then magnesium may help ease anxiety, restless legs, muscle cramps, migraine and improve overall sleep. You should take roughly twice as much calcium as magnesium.
How to take supplements
  • Swallow with a big glass of water. Fluid intake is important to dissolve the tablet, especially for water-soluble nutrients such as B vitamins and vitamin C.
  • Avoid coffee, tea and energy drinks (these also contain caffeine) as caffeine can interfere with the absorption of nutrients. And it's best to wait for an hour after drinking coffee to take supplements.
  • Taking a multivitamin could be a waste of money, as some of the nutrients can compete for absorption. And as they contain both water-soluble and fat-soluble vitamins, taking them on an empty stomach means you don't absorb much of the fat-soluble ones, while taking them with a meal may impair absorption of water-soluble ones.
  • Don't eat nuts before taking minerals (e.g. iron, calcium and magnesium). Phytic acid found in nuts, beans and bran binds to minerals in the gut, meaning that they won't be properly absorbed. This only affects absorption of nutrients eaten at the same meal.
Source: Are you taking your vitamins the right way - or just wasting your money? Experts say that when you take them can determine how effective they are by Caroline Jones, Daily Mail, 28 Feb. 2022


Sunday, 1 May 2022

The Sleeping Beauties by Suzanne O'Sullivan

 The Sleeping Beauties - and other stories of mystery illness by Suzanne O'Sullivan (Picador, 2021)

[The author is a medical neurologist. Her other works on this topic are: It's all in your head: true stories of imaginary illness and Brainstorm: detective stories from the world of neurology.]

 The mind has a lot of power over the body. People can lose consciousness or have seizures through a psychological mechanism as well as part of a disease process. At least a quarter of neurology referrals believe they have epilepsy but instead have dis-associative or psychosomatic seizures. Up to one third of referrals attending a neurology clinic are likely to have a psychosomatic complaint - real physical symptoms from psychological or behavioural causes. The presenting symptoms can also be skin rashes, breathlessness, chest pain, bladder problems, diarrhoea, stomach cramps, and more. While these are symptoms of real problems, when scans and tests fail to reveal a physical cause, many still doubt psychological causes. With no single diagnosis or set criteria for conditions like autism and ADHD, there is a risk of interpretation by the user. Sometimes illness is a sign that the life we have chosen for ourselves is not the right one. Anglo-American cultures tend to consider depression as physiological and psychological, where other cultures regard it as situational.

For most of the 20th century psychosomatic disorders have been labelled 'hysteria' and 'conversion disorder' and viewed from Freud's theories, with hidden psychological trauma converted into physical symptoms. Many people, including doctors, still regard repressed trauma and denied abuse as the full explanation for all psychosomatic disease, even when the patient refuses this diagnosis.

Hysteria (and conversion disorder) are more aptly termed 'functional neurological disorders' (FND). In neurology the term 'functional' has replaced 'psychosomatic'; 'functional' indicates a problem with how the nervous system is working and implies a biological cause, not a mental one. The term 'mass psychogenic illness (MPI) has replaced 'mass hysteria'. A true MPI outbreak actually says more about the society in which it occurs, than it does about the individuals affected. 

  • Mass anxiety disorder occurs out of the blue, without any preceding stresses needing to be present. It usually affects young people and happens in contained environments, such as schools. It spreads by direct contact and comes and goes quickly.
  • Mass motor hysteria can affect people of any age, is more insidious in onset and lasts longer. Typically occurs where there is a background of chronic tensions within a close-knit community.  

The big problem with any MPI is how it is perceived and understood publicly. The way such illness is defined and discussed by the small number of experts who study it is often different to how it is understood outside those circles. In the medical field it is a disorder that arises from group interaction, and is sometimes referred to as a mass sociogenic illness - a social phenomenon rather than a truly psychiatric disorder. By others it is largely presented as a psychological problem, focusing on the individual and ignoring the role of the community. The cliches associated with it are very demeaning to young women, and can make the diagnosis unacceptable for social groups that do not easily fit that category, such as older people and males, or even to conflate it with 'faking' illness.

The media do not help with reports of 'mystery illness', even when a diagnosis of 'non-epileptic seizures' has been given. Reporters often state that 'medical tests have not been able to provide any answers, when they do not recognize the diagnosis is a legitimate medical condition. Publicity can even cause further cases in some circumstances.

Western doctors are trained to interpret symptoms in a literal way and treat as personal, but every medical problem is a combination of the biological, the psychological and the social. Positive blood tests or scan results provide evidence that allows others to believe in the suffering.

People find it hard to accept a psychosomatic disorder diagnosis. There is no correlation between severity or chronicity of disability and the disease process. 'Psychosomatic' and'functional' do not imply less severe or less disabling symptoms, nor are they imaginary; they are not self-limiting and can cause sustained disability. For many, they are a self-perpetuating phenomenon. Some get better, but for others the symptoms are intensified by the experience of being sick. Social and medical interventions affect the way a patient feels about the problem, and can even make things worse. More tests and less understanding of doctors' explanations leave people more confused and worried, leading to further searches for symptoms and possible external causes.

Functional neurological disorders are usually anatomically and biologically impossible. Symptoms come from the unconscious plus an inaccurate understanding of how the body works. Reading descriptions of psychosomatic disorders, people typically relate to some part of the illness described and hope to get a formal diagnosis. If a doctor is sure that a positive asylum decision is the only cure for resignation syndrome, people get to know this, and subconsciously further spread the outbreak. And sadly, many people still struggle to accept a diagnosis of of psychosomatic or functional illness and cannot let go of the idea that there is another explanation - a virus, a toxin or an unknown illness. Despite public perception, epileptic seizures are generally brief, while dis-associative seizures last a long time. FND disorders are not imaginary, but even medical practitioners have been know to dismiss them as malingering, while the public view is that it happens to damaged people.

It is not known why young women are more likely to be affected by these disorders, but theirs is typically a voiceless position in society, a strange and impossible position that women are supposed to occupy. Young women are told they are equal, but held back if they try to assert their equality. Also physical changes - cyclical hormones and tendencies to low blood pressure and fainting - can lead to dis-associative seizures. They can be expected to live traditional conservative lives while finding themselves sexualised by older men.

The book includes chapters on specific psychosomatic outbreaks in various countries.

Sweden: From 2005, some Yazidi refugee children, boys and girls, became anxious and depressed, withdrew into themselves, soon couldn't go to school, spoke less or not at all and eventually appeared to be in a coma, had to be fed by nasogastric tube and could not open their eyes. Between 2015 and 2016, 169 Yazidi refugee children in various towns were affected. Medical tests showed no disease so doctors diagnosed 'resignation syndrome', which exclusively affects children of asylum seeking families (who have usually suffered persecution in their homeland). The asylum process is slow, and might initially be refused. During this period children integrate in school and area, and since they speak and write Swedish, they often translate any letters sent to their parents. Medical assessment of age is fraught with error due to the effects of chronic deprivation, abuse and malnutrition that caused their flight. When granted residency, children usually 'woke up' though not overnight. Yazidi children arriving in other countries do not suffer from this  syndrome. Why? Until recently in Sweden, families with children with resignation syndrome were automatically granted automatic asylum, but with record numbers arriving in 2014, emerging hostility to immigrants led to this being dropped.

Texas USA: This state has a population of ethnic Miskito originally from Nicaragua. They have had outbreaks of 'grisi siknis', that were first reported in the 1970s but actually started earlier in Nicaragua. Symptoms include tremors, difficulty breathing, trance-like states and convulsions and begin with sufferers having a visual hallucination of being visited by a frightening stranger of the opposite sex who comes to lure the victim away. In Nicaragua, to escape they run into the jungle, the community find them and a local healer (shaman) will say ritual prayers. In Texas, typically the outbreaks occur in schools (mostly girls but sometimes boys) and when they attempt to run away they are restrained by family despite resisting strongly. In the Miskito community, young girls are subject to a lot of attention from (often older) men trying to pressure them into a relationship. Sometimes the interest is welcome and exciting for a girl but it conflicts with the moral standards of a conservative Christian church they follow. Being afflicted also means you are attractive. Grisi siknis is now part of Miskito culture.

Khazakhstan: The mining town of Krasnagorsk did well for many years with a population of c.6,500 in the 1960s, and was well resourced. When the mine shut in the 1990s, almost the whole of the town became unemployed overnight. As people left for jobs elsewhere, numbers dropped to c.300 in 2010 and just 30 in 2017. From 2010 people reported a wide range of symptoms, but generally older people tended to have long periods sleeping and children to be hyperactive. Cases often occurred in clusters following social gatherings at which happier times were recalled. People did not want to move, but sickness gave a reason why they had to go, and then environmental poison was suggested as a cause for the sickness. Fears about poisoning from the mine were not put to rest despite negative soil and water tests but the government resettlement offer of a move to Esil was not  popular. Unhappy that often smaller accommodation was offered, people felt there was official pressure to move. 

Asia: The Hmong are an ethnic minority in Vietnam. Originally from China, which they had fled at the end of the 19th century to escape persecution, they were then recruited by the US for the Vietnam war; when the US abandoned Vietnam, many Hmong fled to the US as refugees. Within a year there was a high incidence of men dying overnight with no known cause. As illiterate immigrants, used to mountain life and polygamous kinship structure, they found it difficult to live in confined spaces, or to use modern appliances. Their belief systems already included death caused by evil spirits, as do other non-western cultures; but even in the west it is common for people to know of someone who has died within hours or days of a beloved life partner.

Cuba: In 2017 at a time when relations between Cuba and the US were still starting to settle, a group of recently deployed US State Department employees developed serious but unexplained medical problems: headaches, earaches, hearing impairment, dizziness, tinnitis, unsteadyness, visual disturbances, memory problems, difficulty concentrating and fatigue. Despite intensive investigations, no cause was established. All brain scans were normal. Experts were clear that a sonic weapon that could such symptoms did not exist, medical experts were clear that sound did not cause brain damage, but media interest prolonged the investigations. At the  time, relations between the countries were still strained and there was concern over spying, though no physical evidence was ever found.

Columbia: In 2014 a group of schoolgirls had faintings and convulsions that were diagnosed as 'mass hysteria'. Such outbreaks are typically gone in a day but this was still ongoing five years later. Blood tests, brain scans and EEG tests were all negative, but parents felt that some results were held back. Initially media  publicity led to public labelling of the girls as 'crazy', but the community view now is that the HPV vaccine caused it, and referring to supposed incidents in Japan and Italy. This is despite the vaccination being a second dose, the first being given a month previously and having caused no symptoms.

Korea: There is an illness called hwa-byung, meaning fire illness. The condition is referred to as a culture-bound syndrome or folk illness. While the main symptom is a sense of heat or burning all over the body, it also has a cultural meaning. Associated with stress caused by infidelity, it is an acceptable way of asking for support.

END