This book is an excellent complement to "Survival of the Sickest" making it clear that we have co-evolved with life's oldest members - bacteria, viruses, and parasites. And as we face this fact, it challenges our notion of disease, and who we are exactly. Many thought provoking passages.
Is sex sick?
The need for sex can be laid at the feet of pathogens, which cleaved us from an early evolutionary asexual stage (think cloning or budding) into 2 sexes, with all the turmoil that followed. Disease has gone onto influence how we choose our mates, how we produce and protect our children, the reason we distrust strangers. We may be attracted to each other because we see, however unconsciously, a partner who would be more resistant to disease. P5
You'd think you're back would stop hurting after 4M years
The evolution of bipedalism, thought to have arisen over 4M years ago, may have freed humanity’s hands, but it also caused a shock to the skeletal system from which we have still not recovered. Anthropologists speculate that our joints would have to be too large for efficient locomotion if they were also stable enough to bear our body weight, resulting in the current compromise of aching backs and knee braces. P15
FEVER THERAPY
The Nobel Prize winning breakthrough for treating syphilis patients came in 1927 when Austrian Julius Jauregg deliberately infected patients with malaria to induce high fevers; most of the patients showed striking disease remission; where upon he cured the malaria with quinine… More recently malaria therapy has been proposed for Lyme disease. P18
MORE
Rabbits can lower the number of disease causing bacteria in their systems more easily if they develop a fever. Goats infected with a parasite and then given a fever reducing drug died, while those left untreated had a mild infection and recovered… Artificially lowering body temperature seems to interfere with the ability to fight off a variety of infections… Fever may be a helpful, adaptive response of the body to illness, not the menace it became known as in the last century. P21
So why are we so deathly afraid of fever then?
19th century experiments on lab animals were demonstrating high temperatures as heatstroke, not fever. True fevers involve a recalibration of the body’s internal thermostat, so that instead of keeping 98.6, the new set point is 101. Which is why sitting in a sauna is not the same as having a fever. P21
If fever helps our immune system, why aren't we always feverish?
Fever is metabolically quite costly, requiring extra energy that must be extracted from food to create this heat, rather than being used for a multitude of other activities… Some scientists have speculated that lower temperatures stave off aging by reducing the amount of toxic materials produced by the cells during an immune response, making it best to maintain the lowest possible temperature as we can. P22
WHO really knows the facts about fever
WHO (World Health Org) came to a rather startling conclusion after studying the research on fevers in children; fever reducing drugs in children made no difference in the outcome of the disease, the duration of the symptoms, or even the comfort level... Medical researchers have also debunked 2 common misconceptions about high fever in children: that it results in seizures, and that fevers must be controlled before they reach 106 to prevent brain damage… While it is true that temperatures of 106 are potentially damaging, such temperatures are virtually always the result of heatstroke or brain injury not infection, and so fears of a cold or flu caused fever rising to this level are groundless… WHO states “The principle rationale for fever reducing therapy is to soothe worried parents and to give them the sense that they are controlling the child’s illness.” P23
So is it feed a flu, starve a cold or vice versa? Well, how about neither.
Reduced appetite during sickness may be linked to a mechanism for eliminating virus infected cells…Apoptosis targets cells that are already infected with virus particles. Food restriction makes this process happen more easily… It is possible that the mild loss of appetite associated with illness is therapeutic. P24
The one way switch is now broken
The more body fat a person has, the more leptin he produces, and leptin reduces appetite. But administering leptin to obese people doesn’t help much, and in fact these people already have high levels of leptin relative to thin people. So what if appetite is stimulated by low leptin levels. Recognizing obesity simply wasn’t necessary in most of our evolutionary past. P25 What’s going on? Perhaps the leptin system was built to only help us in one direction – to encourage us to eat more not to eat less. Think about it, evolution has not had to deal with a modern situation of 10,000 calories available to you in your fridge 24/7
Cystic Fibrosis to the rescue
CF is not a disease but an evolutionary adaptation to cholera and other diarrhea inducing illness. Having a single CF gene (you need 2 copies to be disease stricken) showed that you secreted far less fluid than normal. Researchers suggested that humans with 1 copy would have been at an advantage when cholera epidemics struck. P35
How to raise allergy free children? Throw them in the pigpen!
Having older siblings is particularly likely to be associated with decreased incidence of asthma and allergies, as is the presence of a pet when a child is born. Rural children are also less affected. P41
How did we come up with this [lack of] hygiene hypothesis?
In 1989, researchers theorized that lower standards of living, poor healthcare system, and more polluted environment of East Germany would cause a higher rate of disease than the cleaner West. The opposite turned out to be for children, with children from the East being much less likely to suffer from allergies and asthma… The hygiene hypothesis suggests that diseases such as asthma and allergies arise from an environment that is too clean, so that the normal stimulation of the immune system during infancy is missing, impairing its ability to respond normally to actual pathogens but ignore harmless entities like pollen… Researchers have noted that in areas where malaria is rampant, people suffer from far fewer autoimmune diseases… The rate of hayfever is lower where the rate of TB is higher… Italians who have been exposed to Hepatitis or other parasites were less likely to suffer from asthma or hayfever… African children from Gabon were 32 times less likely to suffer skin allergies to dust mites. Even the lowly cold is associated with reduced incidence of wheezing caused by asthma. Several doctors have quipped “the cure is the common cold!” p43
Are we vaccinating ourselves into a society of asthmatics?
The immune system has killer T cells and helper T cells. The helper T cells come in 2 types Th1 and Th2. Th1 is concerned with bacterial and viral diseases, and Th2 with worms and parasites… In countries with scrupulous hygiene, where children are vaccinated and antibiotics are widely administered, the low level of Th1 stimulation results in an increase in the Th2 response. These exaggerated Th2 responses produce mucous and constrict airway muscles, leading to allergies and asthma. In countries without vaccination and antibiotics, the Th2 responses are activated, but they are regulated by repeated cycles of infection and inflammation, with the inflammation countered by natural anti-allergic reactions… The immune system still respond to pollen or dust mites, but it as if the Th2 arm learns to recognize an innocuous foreign substance for what it is, and has a ‘been there, done it’ reaction, rather than spiraling out of control in a cycle of swollen tissue and drippy glands. P47
Take 2 worms and call me in the morning
Wherever there is deworming you are seeing a rapid rise in inflammatory bowel disease frequency. The worms are thought to stimulate the Th2 response, which then helps to regulate Th1 activity. A malfunctioning Th1 response is characteristic of Crohn’s disease… 4 Crohn’s sufferers were infected with worms, 3 achieved remission, and the 4th showed marked improvement. Not one showed a single side effect, unlike conventional drugs… A study of 29 patients suffering colitis who were entered into a 12 week double blind experiment using worms for treatment. About ½ of the people ingesting worms showed significant improvement vs. 15% of the placebo control group. P52
Think eating worms is gross? Well think about this…
Half the weight of your stool is living bacteria. What are a few worms more or less? P53
Mice reared in a germ free environment must consume 30% more calories to maintain the same weight as conventional bacteria ridden mice. P56
Diarrhea can be ameliorated or prevented by administering a dose of good bacteria (lactobacillus and bifidobacterium) called probiotics. P57
A sampling of microorganisms on tortillas purchased from gloved or barehanded servers. Thankfully, few of the tortillas were contaminated with many bacteria, but if anything, the ones from gloved workers were more likely to harbor germs. The problem is that one almost always contaminates gloves when putting them on. P63
It takes the body several days to generate the targeted antibodies for a particular infection. If a pathogen could change its appearance during this brief period, it could maintain a higher level of virulence. Evidence of this is seen in the parasite that causes sleeping sickness. Its protein coat can undergo many 1000s of alterations in a few days, effectively eluding the immune system. P80
Did parasites cause us to have sex?
Genetic recombination is the mixing of genes. One possibility is that this recombination fostered by sex evolved to clear out the mutations that accumulate when DNA replicates asexually. Because genes realign on their chromosomes every time a male makes sperm or a female makes eggs, the number of mutations diminishes. P89
The reasoning went, that with sex, evolution could proceed more rapidly and species could change more readily as well… But the need for fast evolution isn’t a good explanation for sex for 2 reasons. First, changing rapidly as the epochs go by doesn’t make a species more likely to succeed; plenty of organisms look just like they did eons ago. Second, is that it relies on a benefit for the species not an individual. These good for group arguments don’t work evolutionarily… Which would you rather have 20 lottery tickets with the same number or 10 with different numbers? So producing variable offspring could be beneficial even if those offspring are fewer in number. This sounds fine, but it falls apart under closer examination. The disadvantages of sex are just too large to be offset by a chance at winning in a random draw if what produces the winning ticket is left to chance. Imagine that one lucky offspring is blessed with ‘right’ genes for a specific environment. Those genes can be passed on to others sexually, but they will be watered down with sexual recombination. But you need many such lottery winners, not just one, and further more they have to be appropriate age and sex to repopulate the environment. Sure it could happen, but there is no evidence that it does. And even if sex gave you an initial edge over the environment, it would need to do that again, because the environment does evolve back at you. The biological environment does however… Because natural selection acts on both parasite and host, any adaptation that makes an animal better at resisting will be met with a counteradaptation. Host-parasite interactions provide the constant pressure to reinvent oneself: the perfect inspiration for sex. P92
Think you're a tough guy huh?
Human males who wish they could last longer may be daunted to learn that many insects copulate for hours or even days. Stink bugs mate for 10 hours, golden egg bugs copulate for up to 2 days, and a type of stick insect has been clocked at 79 days. P107
If STDs are harmful, and having more sex partners – at least infected one – increases the likelihood of getting one, it is logical to conclude that natural selection should act on hosts to reduce the risk of transmission by affecting the way hosts mate… First it is reasonable to assume that a high prevalence of STDs would make animals less promiscuous… Second, animals should attempt to discriminate among potential mates and refuse those that appear infected. It turns out that neither of these is borne out in nature. Why? Short term gains can offset long term losses, so while STDs increase with the number of partners, individuals who reduce their partners are simply outreproduced by those who do not. P111
Highly attractive males are also the most likely to be infected, simply because they are doing the most mating. If the choice is between a loser without disease or a superstar potentially infected, females are still likely to benefit by choosing the latter. P114
Is maleness a fatal disease?
Being male is now the single largest demographic risk factor for early mortality in developed countries… Females don’t just live longer, the suffer from less disease. P126
The physiological explanation has it roots in a little known side effect of the very substance that makes males: testosterone… The hormone can depress the ability of immune cells, tissues, and organs to devlop… More indirectly, testosterone can cause levels of cortisol (stress hormone) to increase, which further suppresses the immune system. P130
The only entire class of disease that is generally more severe in women than men are autoimmune disorders in which the immune system is too vigilant… Women seem to produce more T cells. P131
Male ornamentation is a signal of immune health - that explains a lot.
Turkey breeders (and turkey hens) can look at the comb of males and diagnose TB if these parts are bluish, or if the wattles are swollen then cholera can be diagnosed… The degree to which a species is plagued with parasites should mirror the degree of flamboyance its males must evolve. Therefore peacocks should have more than wrens. P150
Polygyny is more common where populations are plagued by diseases such as malaria, sleeping sickness, and worms… Could the heavier parasite burden lead to higher degrees of sexual selection and hence polygny? P161
What would happen if a male cheated – produced a big display without having the good immune genes to back it up? Here is where testosterone comes in. If it is necessary for the production of the secondary sexual characteristics (showy plumage, etc.), but also increases their vulnerability to disease, only those males of particularly high quality would be able to maintain showy ornaments despite the onslaught on their immune systems. P164
It is logical to suggest that animals with sexual ornaments that carotenoids (colors from plants) for their showy colors are therefore signaling both their foraging ability and their health with those ornaments. P182
Even baby animals signal with carotenoids to demonstrate their vigor… Parents dole out their affections unequally, and those chicks with the brightest colors – indicating the greatest health – get the lion’s share of attention and food. P185
Think twice before eating that piece of sushi
With the increase popularity of sushi worldwide, infections of Anisakis worm are on the rise (2000 per year globally with most case in Japan, but the US and Europe come in for their share not only from sushi but smoked salmon, pickled herring, and other uncooked fish). The parasite has to be removed surgically or via a tube inserted into the throat, since drugs are ineffectual. P215
It's a small wormy world after all
More than 1/3 of the world’s population has one kind of worm or another… Virtually all of th'ese infections are due to man’s ineffective insulation from his own excrement. P217
Although saliva is not a completely effective antibacterial agent, it is still helpful in controlling infection, which suggests that concerns about keeping pets or people from licking or sucking on a wound may be misplaced. P224
Humans across all societies show a distrust of newcomers or those who appear different from their usual social group, and several scientists have suggested that xenophobia evolved as an aid to avoiding disease... Certainly, shunning unfamiliar individuals keeps them from infecting you with plague, but it also has a myriad of other functions, and it is difficult to say the least to rule out causes other than disease avoidance for being suspicious of strangers. P226
Disgust at the sight of blood, pus, feces, and vomit evolved as a means to protect us from becoming infected. P226
Strangers are perceived as more disgusting. A survey of 40,000 asked them to choose whom they would least like to share a toothbrush with. Best friends and spouses were most preferred, followed by bosses and coworkers, the TV weatherman, and last the postman… Why in the world are people more comfortable with the weatherman over the postman? The power of TV to forge bonds with our Paleolithic brains. P228
Women’s perception of what is disgusting during pregnancy changes. Immunity is low during the first trimester, as the woman’s body grows to accept the fetus as part of her self rather than an invader… Even after taking the women’s nausea from morning sickness (which is also related to bodies sensitivities to plant toxins – see Margie Profit) into account, disgust levels were highest during the 1st trimester. P229
Here’s an oxymoron: A creationist with drug resistant staph.
If you do something to bacteria, bacteria will do something back to you. Antibiotic resistance is nothing more than evolution by natural selection. P244
Simple soap and alcohol based cleaners kill bacteria without containing antibiotics and without causing problems like the evolution of resistance. Unlike antibiotics which target specific elements of the bacterial structure, soap binds indiscriminately to the bacterial cells allowing them to be washed away. It easy for the bacteria to evolve resistance to a substance with narrow objectives and much harder to evolve resistance to a generalized foe. Also, soap & water or bleach or ammonia cleaners don’t linger on surfaces the way that antibiotics cleansers do, which means there is less danger of killing off innocuous bacteria as well. P247
Is cancer contagious?
Some scientists believe that the sheer magnitude of chronic diseases like cancer and heart disease argues for their infectious cause. The notion that a large proportion of the population would perpetually suffer from a disease that reduced the likelihood of reproduction to be simply implausible… Even a small reduction in the number of offspring an individual has can result in eventual elimination of that individual’s genes. Although diseases that strike late in life will have a smaller effect than those that cut off an individual’s reproduction at the start. Further, humans spend so much of their lives contributing to their children and grandchildren, anything that causes earlier death or disability will be costly…. Furthermore, studies of identical twins, who have the same genes, rarely show that the illness occurs in both members, as would be expected if genes dictate the ailment. P263
[Scientists] believe that schizophrenia is the perfect candidate to have an infectious cause, given the low reproductive rates of schizophrenics… Evolution should have knocked out the genes associated with schizophrenia years ago, since it carries such a high cost… In temperate climates, schizophrenics tend to be born in late winter or early spring, when stillbirths, often caused by prenatal infection, are also at their highest. This argues for schizophrenia being an infection that the mother contracted during early pregnancy and suggests that the culprit is something she is more likely to be in contact with when she spends time indoors… The strongest candidate to date appears to be toxoplasmosis because if a female mammal is infected during pregnancy it can also damage the central nervous system of her fetus. Pregnant women are already urged not to come in contact with cat feces. Children of mothers who were infected during pregnancy show higher levels of mental retardation and seizures. Why the seasonality? The mothers were more likely to be exposed while indoors during certain times of the year… Using a huge sample of mothers from 1959 to 67, researchers found that if a mother had high levels of the antibody [for toxoplasmosis], indicating prior infection, her child was more than twice as likely to become schizophrenic as compared to a child from a mother who tested negative for the antibody. P263-4
Maybe Count Dracula had malaria?
Female mosquitoes’ (the ones that bite for blood – the males are harmless) saliva has substances that facilitate her feeding, making the blood of her victims flow more readily (anticoagulant). But infection with plasmodium (the parasite that causes malaria) reduces the amount of these substances by ¾’s, making blood much more difficult to suck up… 22% of infected mosquitoes bite more than 1 person – thus helping to foster to the spread of the disease. This is versus only 10% of noninfected mosquitoes who bit more than 1 person. P275
Bats do not commonly carry rabies and when they do are unlikely to become aggressive and attack people; although handling a sick bat is still unwise. P276
Are we mice or men?
Toxoplasmosis is transmitted from its intermediate host (mice/rats) to its final host (cats) by predation. [How does the parasite foster this predation for its benefit?] Uninfected rats show a healthy aversion of cat scented areas, while parasitized rodents frolicked with abandon in them… This reckless behavior is clearly advantageous to the parasite… People are rarely preyed upon by cats but traces of infection are found in anywhere from 22% to 84% (France has one of the highest rates of infection!). Undercooked meat can be a major source (steak tartar bon appetit)… Infected men showed a greater propensity for disregarding rules while infected women were more outgoing, trusting and self assured… Infected people had slightly longer reaction times, a response that seems consistent with the effect on rodents; slower reaction times would presumably make a rat (or a person) easier prey… Those people with more recent signs of infection had a higher accident risk than people whose infection had been present for a long time... Even though humans are not the intended host of the parasite, it still influences the same brain regions that make the rats more vulnerable prey. P289
Monday, January 28, 2008
Monday, January 07, 2008
*** Survival of the Sickest by Dr. Sharon Moalem
Fact: Bacteria need iron to survive and reproduce
Snot’s there for a reason
Your body’s orifices are patrolled by chelators – proteins that lock up iron – in your salvia and mucous, because infectious agents need iron to survive… When we’re first beset by illness, our immune system kicks into high gear and fights back with what is called the acute phase response. The bloodstream is flooded with illness fighting proteins, and iron is locked up to prevent invaders from using it against us. P7
Egg whites to the rescue
Egg shells are porous so the embryo can breathe. The problem with a porous shell is that nasty microbe can come in as well as air… Egg whites are chock full of chelators to protect the yolk from infection. P8
Breast milk contains lactoferrin – a chelating protein that binds with iron and prevents bacteria from feeding on it. P8
Bloodletting: it does a body good.
A Canadian physiologist discovered bleeding animals induces the release of vasopressin; this reduces their fevers and spurs the immune system into higher gear. The connection is not unequivocally proven in humans, but there is much correlation between bloodletting and fever reduction in the historic record. Bleeding may have helped infection by reducing the amount of iron available to feed an invader… When you think about it, the notion that humans across the globe continued to practice bloodletting for 1000s of years probably indicates that it produced some positive results…. Bloodletting is the treatment of choice for hemochromatosis (more about this disease later) – which causes the body to hoard iron. P18
Hemochromatosis is a condition where the body is constantly in an iron locking state. With all of this iron in their systems, victims should be a magnet for infection and the plague in particular, right? Wrong… The excess iron isn’t distributed throughout the body evenly. Most cells do end up getting too much iron, except one particular cell ends up with much less iron than normal; the macrophages of the immune system… New research has demonstrated the iron deficient macrophages are indeed the Bruce Lees of the immune system. The iron poor macrophages crushed the bacteria compared to normal macrophages. P14 So what’s the downside? You eventually die of rust after about 40 years… But go back to the middle ages beset with plague, and a meager lifespan capped at 40 for a host of other reasons. Sounds like a good deal now?
Warning! Honey and formula don’t mix: No joke
A foreign doctor working in
Is the cure worse than the disease?
2% of people of European descent are carriers of one gene of cystic fibrosis, making the mutation very common. New research suggests that carrying a copy of the gene seems to offer some protection from TB… TB caused 20% of all deaths in
Tomorrow's forecast, light rain followed by an ice age. You laugh, but see below
Ice cores have revealed that the most recent ice age event – Younger Dryas – ended in just 3 years… What’s more the onset took just a decade… Dr Weart in his 2003 book summed it up: “Swings of temperature that scientists in the 1950s believed to take 10,000s of years, in the 1970s to take 1000s of years, and in the 1980s to take 100s of years, were now only found in decades.”… In fact, there have been a score of these abrupt climate changes over the page 110,000 years; the only truly stable period has been the last 10,000 P32
Brown fat to the rescue
A portion of fat in newborns and some adults is specialized heat generating tissue called brown fat, which is activated when the body is exposed to severe cold. When blood sugar is delivered to a brown fat cell, instead of being stored for future energy, it converts it to heat on the spot. It can burn upto 70% more fat than normal fat cells… Shivering uses muscle movement to generate heat, is only good for a few hours; once you exhaust the blood sugar stores in your muscles and fatigue sets in, it doesn’t work anymore. Brown fat can go on generating heat for as long as its fed, unlike other tissues, it doesn’t need insulin to bring sugar into cells. So how do you get this great stuff? To accumlulate brown and get it working you need to live in extreme cold for weeks – we’re talking North Pole cold. And that’s not all – you’ve got to stay there. Once you stop sleeping in your igloo, your brown fat stops working. P37
Ever get that urge to purge?
The body has another response to the cold that is not completely understood, but you’ve probably experienced it. When most people are exposed to cold for a while, they need to pee… One theory is that as the blood pressure climbs in the body’s code because of constriction in the extremities, the body signals the kidneys to offload some extra fluid. But this theory doesn’t fully explain the phenomenon… p38 Think diabetes of all things. More to come below.
Care for a frogsicle?
Sugar dissolved in water, lowers the freezing point, acting like an antifreeze… The North American wood frog can freeze solid each year… Just a few minutes after the frog’s skin senses that the temperature is dropping near freezing it begins to move water out of its blood and organ cells (frozen water crystals will rupture tissue), and pools the water in its abdomen. At the same time, the liver begins to dump massive amounts of glucose sugar into the bloodstream, pushing its bloodsugar level 100 fold, preventing whatever water remains in the frog’s bloodstream from freezing. P43
Antifreeze is in the genes
Is it possible that some humans adapted to the cold in a similar manner? Is it a coincidence that people most likely to have a genetic propensity for a disease characterized by exactly that – excessive elimination of water and high levels of blood sugar) are people descended from the exactly those places most ravaged by the sudden onset of an ice age 13,000 years ago? It’s hotly controversial but diabetes may have helped our European ancestors survive the sudden cold of the Younger Dryas… Imagine a small group of people faced with year round frigid temperatures, their insulin supply slowed, allowing their blood sugar to rise. They urinated a lot, to keep internal water levels low (recent US Army study data shows there is very little harm caused by dehydration in cold weather – ie. you can’t get heatstroke). Suppose these people used brown fat to burn their oversupply of sugar. Perhaps they even produced additional clotting factor to repair tissue damage caused by ice crystals. It’s not hard to imagine that these people might have had enough of an advantage over other humans, especially if they would survive long enough to reach reproductive age… More evidence: Rates exposed to freezing temperatures become resistant to their own insulin. Essentially they become diabetic in response to the cold. In areas with cold weather, more diabetics are diagnosed in the colder months… Children are most diagnosed with Type 1 diabetes when temperatures start to drop in late fall… Fibrinogen, the clotting factor that repairs ice damaged tissue in the wood frogs, also mysteriously peaks in humans during winter… A study of 285,000 diabetics revealed that blood sugar climbed dramatically in the colder months and bottomed out during the summer… Diabetes has some deep connections to the cold. P46
Because sunlight converts cholesterol to vitamin D, cholesterol levels can be higher in winter months when we continue to make and eat it, but there’s less sunlight to convert it. P51
Sunblock blocks the UV rays that not only give us sunburn, but those same rays help us make vitamin D. p51
Darker skin isn’t just an adaptation to protect against sunburn – it’s an adaptation to protect against the loss of folic acid. The darker your skin, the less UV light you absorb (and the more exposure you need for vitamin D production). P53
Best way to prevent a sunburn; take off your sunglasses.
As everyone knows skin color changes in response to sun exposure. But the reason it changes is not because of the skin expose itself. The melanocytes that produce melanin to darken your skin are controlled by hormones secreted from the pituitary gland in your brain (not your skin). This gland gets its information that you’re in the bright sun from the optic nerve via your eyes, not from the burning sensation on your skin. Guess what happens when you wear sunglasses? Much less sunlight reaches the optic nerve, leading to much less melanin production – and much more sunburn results. P54 Possible dark skinned counter strategy. Since dark skinned folks have a hard time creating vitamin D in the winter, wear sunglasses as much as possible during the shorter days to keep your skin light.
We carry sufficient genes within our gene pool to ensure that within 1000 years of a mass latitudinal migration, that our descendants would have skin color dark enough to protect folate, and light enough to maximize vitamin D protection. P56
High cholesterol saved your ancestors
Dark skin evolved to protect folate, but you can’t turn it off when you need to whip up a batch of vitamin D. So even if dark skinned people lived in a sunny climate, their skin prevents them from stocking up on vitamin D. Evolution took that into account, and gave dark skinned people a protein called ApoE4. And guess what this protein does? It ensures that the amount of cholesterol flowing through your blood is cranked up. With more cholesterol available for conversion, dark skinned people can maximize whatever sunlight penetrates their skin… Much farther north where there is little sun in the winter, this same protein appears again. Why? Even with the benefit of light skin, there is not much sunlight to go around. So ApoE4 keeps cholesterol levels cranked up, allowing light skinned folks to compensate for limited UV exposure… Of course, all that extra cholesterol comes with a trade off. It puts people at greater risk for heart disease and stroke. P57
In
Skull shape may have evolved as a mechanism to facilitate storage and release of heat depending on a population’s climate. P63 I would expect spherical shapes in very cold climates and elongated, narrower shapes in hot areas for surface to volume reasons.
Dense hair on arms and legs may have been response to malaria. The densest hair is found in the same places where malaria is most common in the eastern
Slavery leads to high blood pressure
When Africans were taken to
The risk of prostate cancer for Black men climbs from south to north… There is growing evidence that vitamin D inhibits growth of cancerous cells in the prostate. P67
Favism is an inherited enzyme deficiency that prevents you from eating fava beans without having intestinal issue is carried by 400M people. It is the most common enzyme deficiency in the world. In extreme cases, fava consumption can lead to death. P73 By now you can guess that there is a good reason for 400M to carry a potentially fatal condition. Read on.
Soy milk birth control?
Clover, sweet potato, and soy all belong to a group of plants that contain phytoestrogens. Phytoestrogens mimic the effect of animal estrogen. When animals eat too much of these plants, the overload wreaks havoc on their reproductive capability… The Pill is based upon the phytoestrogen from yams… Many processed foods (including baby formula) use soy… There’s a growing concern among scientists that we don’t have a handle on the potential long term effects of what seems to be an ever greater level of phytoestrogens and soy in our diet. P79
The average person eats 5000 to 10000 natural toxins every year. Researchers estimate that 20% of cancer deaths are related to natural ingredients in our diet. P83
Skip the organic celery
Organic farmers don’t use pesticides (with the goal of providing a healthier product). But by leaving their crop vulnerable to attack by insects and fungi, those plants respond by producing massive amounts of natural toxins. By keeping off man made poison, the organic celery farmer is all but guaranteeing a biological process that will end with lots of poison in the plant. P87
People who have Favism lack an enzyme that mops up free radicals in their blood. This abundance of radicals leads their blood cells to break down and results in anemia…Such red blood cells are not just less hospitable to malaria, they are also taken out of circulation sooner than those of people without the mutation, and that disrupts the parasites life cycle. This explains why populations exposed to malaria would select for favism… But why do these same people cultivate and eat fava beans if they can’t properly digest them? The bean have lots of free radicals, and accelerate the break down blood cells, heightening the anemia. So they are a good thing to eat during mosquito season. P90
Some scholars think the Rod of Asclepius – snake wrapped around a staff – was originally for the rod used to wrap a Guniea worm around as it erupts from your skin. P96
Who’s the boss?
An adult contains 10 times as many foreign cells as your own cells. There are over 1000 different types of microbes that live and feast on you – while you’re alive. All together they weigh about 3 pounds, and number upto 100 trillion. Collectively they contain 100 times more genetic material than your DNA. P98
Remember how almost every form of life needs iron to survive? Well, one of the exceptions is also one of the most common probiotics, a bacterium called Lactobacillus, which uses cobalt and manganese instead of iron – which means its not hunting yours. P99
Toxoplasma Gondii is a parasite commonly associated with cats (toxoplasmosis ring a bell). In the
Pinworm infection afflicts 50% of American children. The worms live in the intestine and grow to be about ½ inch long. When the child defecates, the eggs are released. These eggs contain an allergen that causes serious anal itching. When a child scratches, he ends up getting the eggs under his nails. And even with normal hand washing, the eggs are missed under the nails. When these children touch surfaces – toys, handles, food, etc. They are transferred to others, and the cycle starts over…. The worms don’t usually cause any damage other than the itching. P111
A sick primate that is abandoned by its community may actually be partly responsible, wandering away to protect its kin from infection. This phenomenon has been documented in swallows and beetles; when they’re infected with parasites, members of both species appear to migrate away from their kin. P115
The cold virus has hit the evolutionary jackpot; it’s evolved to a level of virulence (ability to kill the host) that guarantees our mobility and its survival. It may never evolve to kill or seriously incapacitate us – unless it finds another medium to move around to infect hosts. When an infectious agent doesn’t need its host to get around, things can really heat up. Malaria has evolved to incapacitate us, it wants us vulnerable to attack by its vector – mosquitoes. In fact, there is an evolutionary advantage for the malaria parasite to push its host toward the brink of death. The more parasites in your blood, the more the mosquito will ingest. Cholera is similar – it doesn’t need us moving around to find new hosts as long as it finds its way to the water supply… Cholera actually has an advantage in evolving towards virulence – as the bacteria reproduces ruthlessly, causing more and more diarrhea, the infected person may excrete as many as a billion copies of the organism, increasing the likelihood of new infections. P120
The worst flu outbreaks of the 20th century followed sunspot peaks in radiation… Outbreaks and pandemics are thought to be caused when a mutation occurs in the DNA of a virus, when a virus acquires new genes from a related virus strain… Mutations can be caused by radiation. Which is what the sun spews forth in significantly greater than normal amounts every 11 years. P131
Nobel winner Barbara McClintock observed that jumping genes [causing mutations] were jumping during times of stress, and that they tended to jump to certain genes more than others… She believed the genome directed the jumpers towards those places where mutations were likely to have a beneficial effect. P139
Bacteria can hyper mutate, allowing the bacteria to produce the mutations they needed to survive about 100M times faster that the mutations would have otherwise (randomly) been produced. P141
The notion that evolution was characterized by a state of general equilibrium punctuated by periods of significant change that were brought about by large environmental shifts. Is it possible that jumping genes helped species adapt their way through these evolutionary exclamation points? You bet. P147
Persisting viruses in our genome have as much at stake in our survival and reproduction as we do, since they are part of our DNA. Over the past few millions of years, we’ve given them the ride of their life, in return, they’ve given us the chance to borrow some code from their huge genetic library… How big is the viral library on earth? Try to imagine all of the viruses in the world – all 10^32 of them. If you laid out all of the DNA in them end to end it would stretch 10M light years! By tomorrow, most of them would have spawned a new generation. P152
A baby girl born in 2000 has a 40% chance of developing Type 2 diabetes. P155
The desert locust live in 2 remarkably different styles depending on the availability of food and the density of the locust population. When food is scarce, locusts are born with camouflage and lead solitary lives. When rare period of rain produce major vegetation growth, everything changes. As the extra vegetation dies off, the locust find themselves crowded together. Suddenly baby locusts are born with bright colors and a hankering for company… These locusts swarm, feed together and overwhelm predators by sheer numbers… The DNA doesn’t change, but the way it’s expressed does. The characteristics of offspring are controlled by epigenetic effects that occur during fetal development. The mother’s experiences are influencing gene expression. P161
Epigenetic mutation can happen in humans.
A harsh winter and a cruel embargo by the Nazis combined to cause the Dutch famine of 1944-5, killing 30,000. Birth record analysis from those times has revealed that women who were in the first 6mos of pregnancy gave birth to small babies who grew up to be more prone to obesity, coronary disease, and a variety of cancers… An even bigger surprise around 20 years later indicated that the grandchildren of those women were also born with low birth weights. P167 Why? A woman is born with all of her eggs.
Because those eggs, which later became the grandchildren, of those first underweight babies were formed in the womb as well under the same epigenetic stress.
In October and November of 2001 (after 9/11) – in CA – there was a 25% increase in male miscarriages. Something – and we don’t know what – in the mother’s epigenetic architecture sensed she was carrying a boy and triggered a miscarriage… We can speculate why this occurred. Males are more demanding on the mother’s body during pregnancy and less likely to survive if malnourished as a child. Perhaps we evolved a kind of automatic resource conservation system that is triggered in times of crisis. Lots of females and a few strong males gives a population a better chance for survival than the other way around. P179
Progeria and other accelerated aging diseases suggest that aging is preprogrammed – in the genes. Think about it if a genetic error can trigger accelerated aging in a baby, then aging can’t only be caused by a lifetime of wear and tear. The very existence of progeria demonstrates that there could be genetic contols for aging. That of course raises a question: Are we programmed to die? P185
Why would we evolve a limit against cellular reproduction? In a word: Cancer… The Hayflick limit [number of times a chromosome can be copied before the telomeres are clipped] prevents a cells unchecked reproduction, shutting down tumor growth before it really gets going. P187
Aging acts like a biological version of planned obsolescence… By clearing out older models, it makes room for newer ones. Second, aging can protect a population by eliminating individuals that have become laden with parasites. P191
Are we aquatic apes?
Some think that our ancestors spent a lot of time in and around the water, so much so that it influenced our evolution… Water may have made the birthing process easier.... Italian researchers compared 1600 water births to conventional births over the same period. First, there was no increase in infection in either mothers or newborns. In fact, water born babies were better protected against aspiration pneumonia. Babies don’t gasp for air until they feel air on their face; when they’re underwater, the dive reflex triggers them to hold their breath. Conventional babies take their first breath sometimes before a doctor can clean their face of birthing residue that can cause an infection… The study revealed more benefits. First time mothers had a much shorter first stage of labor… They had a dramatic reduction in episiotomies –vaginal surgery… And the vast majority needed no painkillers. Only 5% asked for an epidural compared to 66% of conventional birthing mothers. P204
Saturday, January 05, 2008
** Rational Exuberance by Michael Mandel
If the
Periods of innovation and exuberant growth also seem to be the periods with the lowest unemployment… Why should this be? During period of cautious growth, companies have only 1 way to boost productivity and profits – by cutting costs and trimming workers… However during period of exuberant growth, both companies and workers have other options. Innovation enables companies to compete by using new technology to make existing workers more productive. And even if workers are laid, there are innovative new industries that are hiring… Workers have something to aspire to – there’s unclaimed territory where smart and hardworking Americans can make their mark. P39
Exuberant growth builds on the real competitive advantage that the
2035 Forecast: Exuberant Growth could save us
Between 2005-2035, the
The uncertainty of innovation has been responsible for all of the big economic forecasting failures of the past. Fore example, nobody expected the sharp slowdown in productivity growth in the 1970s and early 1980s. What was the cause? It wasn’t low capital investment. It wasn’t education as the percentage of Americans with a college degree was rising sharply. Nonfarm productivity grew at a meager .5% per year… One simple explanation that economist dismissed too easily was technological failure. In particular, 2 leading innovations of the 1960s – nuclear power and space travel – unexpectedly turned out to be major disappointments… Similarly it was the unexpected success of the internet that confounded economic forecasters in the 1990s, when many forecasters consistently expected Europe to grow faster than the
The Next Breakthrough?
Communications: Advanced telecom
Materials: Nanotechnology
Health: Biotechnology
Energy: Fuel cells, solar
Transportation: Space
Why biotech won’t help the economy?
To help the economy a breakthrough biotech drug/therapy it has to satisfy 2, not necessarily compatible objectives. 1st it would have to be successful treating an important disease, which would make it profitable for the company producing it. At the same time, it must reduce the total health care spending in the economy, or it merely means taking dollars from an older therapy and applying it to a new one. What about increased lifespan? That merely increases the population, and at older ages, it may even increase the overall health care spend since everyone dies of something eventually. P104
Bet on telecom – but not on the existing players
Telecom has several advantages. The technology works and it doesn’t have any big safety considerations to worry about. And there are applications for all the new capabilities. There are 2 big hurdles that telecom faces. 1st is the uneven state of broadband access [this seems likely to be fixed with new/cheaper technology]. The 2nd is the ever increasing hold of the large telecoms on the market… Without innovative energies from new firms, the process of change goes much more slowly. That negates one of the main competitive advantages that the
Keep an eye out for an energy breakthrough
Energy innovations have been an absolutely critical part of every industrial revolution in the past… Our high tech civilization could be derailed without a breakthrough in either energy distribution or generation… It should be a very good time for the financial markets and VCs to start funding energy start ups. Unfortunately the 3 main candidates for igniting an energy revolution – solar, fuel cells, and nuclear are immature or problematic… None of them leaps up as an immediate candidate for driving the next revolution without some dramatic improvements. P108
Nanotech: Don’t hold your breath on this one until you see a ‘Shockley Event’, where a technology can get on a
Space: Who needs it? Don’t invest here.
If and when a financial crisis comes in China, no one knows whether the political system will end up performing like the US in the late 1980s after the S&L bailout, or more like Japan’s, where in the 1990s it was paralyzed by bad debt… The danger is that
2010s: Back to the 1970s?
What happens after most businesses have been computerized, networked, web-enabled? If there are fewer must have technologies, then we slip back to the 1970s again… It will become harder to justify paying a college grad 60% more than someone with an associate’s degree who can do the same job… It is precisely the routination of technology that poses a deep and hidden danger for the educated classes… The set of routine tasks expands over time… Educated workers are in danger of seeing their jobs deskilled… In such a world, programmers will worry about being replaced by cheaper labor in
People who received college diplomas in 60s, 70s, & 80s had an unfair advantage they didn’t realize at the time. They grew up in a world in which there was very little competition from overseas for type of cerebral, organizational, persuasive activities. Of hat generation of 60s to 80s, 30% of them got college degrees. In
The full impact of a growth crisis does not usually hit until well after the recession is over. For that reason, the beginning of a growth crisis is hard to identify at the time. 1974-5 recession marked the onset of the last growth crisis, despite a strong recovery – growth of 5% over the next 3 years. P174
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