Monday, January 07, 2008

*** Survival of the Sickest by Dr. Sharon Moalem

This book will help to explain that many so called diseases are actually highly evolved adaptations to help our forbears cope with the trials and tribulations that their ancient environment posed. You’ll find the book equally fun and informative, assuming that you are not stricken with one of these maladies, in which case at least you’ll understand how your unfortunate situation came about. Highly recommended!

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 Somalia noticed that despite repeated exposure to a range of virulent pathogens, including malaria, TB, and brucellosis, the population was free of visible infection. They did however suffer from pervasive anemia… After providing iron supplements to portion of the population to cure the anemia, the rate of infection skyrocketed. The Somalis weren’t withstanding these infections despite their anemia, but because of their anemia… In New Zealand, Maori infants are often anemic. Babies injected with iron were 7 times as likely to suffer potentially deadly infections… Across the world, many infants can have botulism spores in their intestines (spores commonly come from honey given to babies as a sweetner – so don’t give anyone under 1 honey!). If the spores germinate, the results can be fatal. A study in CA showed one key difference between fatal and non-fatal cases was if the baby was fed formula or breast milk. Of all the babies who died, all had only been fed formula. P20

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 Europe between 1600 and 1900… Anything that helped protect people from it looked pretty attractive, even if the unfortunate chance existed for a person to get 2 copies leading to cystic fibrosis. P21 Hmm, another book I'm reading says that CF helps deal with cholera.

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 Europe, people used fermentation to purify water for drinking. This created a selection pressure for genes to handle the consumption of alcohol (a poison for most creatures). In Asia, where most folks boiled water for tea, there was less evolutionary pressure to have the ability to break down and detoxify alcohol… This is why many Asian get “Asian Flush” when drinking alcohol. P58

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 Mediterranean (except mid-Africa where the extreme heat was a counterweight to the extra hair). P63

Slavery leads to high blood pressure

When Africans were taken to America as slaves, they were transported under horrible conditions- they usually weren’t fed or given sufficient water. The death rate was very high. It’s possible that those with a natural propensity to retain high levels of salt had a better chance to survive – the extra salt helped them maintain enough water to avoid fatal dehydration… When you couple that ability with a modern diet with high sodium, it results in increased rates of hypertension among African Americans. P65

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 US more than 20% of the population is infected. In France, 90% are infected (there’s a correlation between eating raw meat and infection rates, and the French love steak tartare it seems)… People with compromised immune systems can suffer complications from this infection. Pregnant women who BECOME infected DURING pregnancy can infect the fetus. However, if the mother is already infected, then the baby is safe (thank god for the French). For that reason, pregnant women should abstain from eating raw meat and handling the kitty litter (cats are the carriers for the bacterium). P107

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

1 comment:

Anonymous said...

when dr. sharon moalem talks about the egg white part, he is wrong in his book because he says that the yolk is the chick that is being protected at an embryonic state when in reality it is actually the white that is the chicken and feeds on the yolk (pg 8 in the book)