« Older Entries

“No day shall erase you from the memory of time”

The city that never sleeps; where dreams are made and realized, (and probably more often than not, discarded); the possibilities endless. I was strolling through the streets and making my way down to the Financial District where I was set to have a tour of the 9/11 Museum.

The day, I was soon told by our guide, was similar to that horrific September 11th morning – where, according to air traffic control, skies were an “extreme clear” – where in a matter of minutes, the world, as we knew it, would change forever.

The Museum is relatively new, only opening its doors to the public in 2014. And although I Iived in NYC last year, I never ended up making my way to the museum. I knew there were two pools, where each of the towers stood, but that was about it. Of course I also knew there was much consultation with the families of the victims as to what the museum should include and how its artifacts presented. With whatever unknown I went in with, I did know that I would feel much of the same emotions I felt on that Tuesday September morning where, in Mr. Moore’s English class, we were told that a plane had crashed into the World Trade Center.

Read more

Chemistry Lesson for Food Babe #5

vani hariJust about everyone now knows something about DNA ( with some obvious notable exceptions). The term “template of life” has been repeatedly used in the press to describe this molecule. That is quite accurate because DNA is like a library of information which tells our cells which proteins to synthesize. Proteins are the key to life because they make up important structures of the body as well as hormones and the enzymes that govern the body’s numerous chemical reactions. DNA is a nucleic acid, a “polymer” composed of pieces called nucleotides strung together like beads on a necklace.

Each of these nucleotides is made up of a sugar called deoxyribose, a phosphate group and a molecule commonly referred to as a “base.” It is the sequence of the bases along the nucleic acid chain that holds genetic information. There are four such bases: adenine, thymine, cytosine and guanine. They are named after the source from which they were isolated. Adenine from the Greek word for gland because it was first isolated from the pancreas, thymine from the thymus, cytosine from cells and guanine from bird guano, the technical name for bird poop.

Yes Ms. Hari, every one of your cells contains the same chemical that is found in bird excrement. This is as relevant as finding azodicarbonamide, the chemical that was used in Subway rolls in yoga mats. (I’m including the molecular structures of the four nucleotides although I’m quite confident they will be meaningless to our intended pupil. I have no idea what she thinks of molecular structures, but given that she thinks that multisyllabic names make a chemical dangerous, she probably doesn’t look on them favourably.)

Read more

Food Babe Lesson #4

vani hariRotting apples release ethylene gas, which is a natural hormone produced by fruits to stimulate ripening. A rotten apple is just an overly ripe apple, producing enough ethylene to “ripen” the rest of the apples in the barrel. The process is usually initiated by physical damage to an apple. The skin becomes bruised, releasing nutritious juice which is very inviting to air-borne molds. When molds set up shop on the apple, ethylene production increases, ripening other apples, inviting more mold! The answer of course is to remove the rotten apple!

Although in this instance the reaction is not desirable, the use of ethylene gas often allows fruit to be picked “green” and to be subsequently ripened during transport in tank cars under an atmosphere of ethylene. This is especially useful in the case of bananas, the most widely consumed fresh fruit in North America. Bananas bruise very easily and could not survive shipping if they were picked when ripe. Green bananas are much more hearty and stand up well during transport. If they are still green when purchased you can ripen the bananas by putting them in a plastic bag with an over-ripe apple!

Our such bases: adenine, thymine, cytosine and guanine. They are named after the source from which they were isolated. Adenine from the Greek word for gland because it was first isolated from the pancreas, thymine from the thymus, cytosine from cells and guanine from bird guano, the technical name for bird poop.

Yes Ms. Hari, every one of your cells contains the same chemical that is found in bird excrement. This is as relevant as finding azodicarbonamide, the chemical that was used in Subway rolls in yoga mats. (I’m including the molecular structures of the four nucleotides although I’m quite confident they will be meaningless to our intended pupil. I have no idea what she thinks of molecular structures, but given that she thinks that multisyllabic names make a chemical dangerous, she probably doesn’t look on them favourably.)

Vani’s take on this would likely be: Do you want a chemical that is used to make pig balls in your bananas?

(Ethylene is used to make polyethylene which is used to make “pig balls” that are thrown into pig pens to give the animals something to play with instead of nibbling on each others’ ears and tails.)

Read more

Cleaning the air with jeans

jeansYou may want them in your jeans, but you probably want to keep them away from your genes. They’re “nano” particles of titanium dioxide, about ten billionths of a meter in diameter that can exhibit beneficial properties not possessed by their larger cousins, but they may also have a darker side.

There are more jeans in the world than people. That stat sparked an idea in the mind of University of Sheffield chemist Tony Ryan. Why not use people’s penchant for wearing denim to help purify the air? After all, the International Agency for Research on Cancer (IARC) classifies outdoor air pollution in Group 1, reserved for substances that are known to cause cancer in humans. It estimates that there are up to seven million premature deaths in the world every year as a result of air pollution.

With thoughts of reducing pollutants such as the nitrogen oxides and volatile organic compounds emitted by vehicles, power plants, residential heating, cooking and various consumer products, Ryan, in partnership with former fashion designer Helen Storey, came up with the concept of “Catalytic Clothing.”

“Catalytic” apparel uses fabric impregnated with nano-sized particles of titanium dioxide to degrade air pollutants. “Nano” means small. So small that the combined surface area of the nanoparticles that are distributed through any fabric is immense. And that matters because the action takes place on the surface of the particles.

Titanium dioxide is a “photocatalyst,” meaning that it can make chemical reactions happen when exposed to the right wavelength of light, in this case ultraviolet. The light energy causes it to release electrons that then target water molecules in the air, breaking them apart to form extremely reactive hydroxyl radicals that then chop up organic compounds into simple molecules such as carbon dioxide and convert nitrogen oxides into water soluble nitric acid. This is not just theory, it is well established technology that already has commercial application, for example in “self-cleaning glass.” A thin layer of titanium dioxide ends window cleaning worries, as long as the climate provides for sufficient sunshine and rain. The chemical can even be mixed into concrete, resulting in self-cleaning buildings such as the Jubilee Church in Rome.

Thanks to titanium dioxide we may never have to confront yellow urinals again. Coating the ceramic with a layer of titanium dioxide, about a fiftieth the thickness of human hair, prevents stains from forming. The technology also has potential in operating rooms where bacteria on floor and wall tiles can be destroyed with fluorescent light, common in hospitals, furnishing enough of the right wavelengths. And how about self-cleaning tiles for the kitchen and bathroom?

Clearly, titanium dioxide photocatalysis is sound technology. But can wearing jeans treated with this chemical actually have an impact on air pollution? According to Professor Ryan, yes. He calculates that that if a third of a million people in Sheffield wore such jeans, nitrogen oxide levels could be significantly reduced. And there is no need to buy special jeans. Titanium dioxide particles stick readily to the fabric so the idea is to add a formulation of the chemical to the water when the jeans are being laundered. The nano particles will stick until the fabric degrades.

As is often the case in science, there is a “but.” What happens if nanoparticles enter the bloodstream? What tissues might they affect? Titanium dioxide has the potential to damage DNA, but to do that it has to enter cells. That is a possibility since nanoparticles are smaller than cells. In the lab, nano titanium dioxide has been shown to damage DNA in human intestinal cells, but only at doses far higher than what could ever be ingested.

In any case, people will not be dining on their treated jeans. But they may be gulping donuts, or a vast array of other foods such as Gobstoppers, M&Ms, pastries or soy milk that have titanium dioxide added to them to provide a more pleasing whitened appearance. Only about 5% of the titanium dioxide is made of nano sized particles, but that has raised concern because IARC has classified titanium dioxide as possibly carcinogenic to humans (Group 2B). This classification is based on inhalation of titanium dioxide dust in an occupational setting, quite a different exposure than eating a donut with a titanium dioxide enhanced white sugar coating. Nevertheless consumer activism has resulted in Dunkin Donuts removing titanium dioxide from the powdered sugar coating on its products. Maybe it can be redirected into catalyst jeans. We really don’t need to make junk food look more appealing, do we?

Read more

Food Babe Lesson #3

vani hariIn our continuing, but extremely challenging effort to educate the Food Babe on science, let us pick on a grapefruit.

“A chance finding of our study on ethanol-drug interactions was that citrus fruit juices may greatly augment the bioavailability of some drugs.” So began a paper published in 1991 in The Lancet, one of the most respected medical journals in the world. Dr. David Bailey and colleagues at the University of Western Ontario had been studying felodipine, a blood pressure–lowering drug, and wondered if it interacted with alcohol. They decided on a double-blind trial in which some subjects were to take the drug with alcohol and some without. This meant that the taste of alcohol had to be masked, and after some experimentation Dr. Bailey concluded that grapefruit juice was up to the task. To the researchers’ surprise, the alcohol had no effect, but in both groups the blood levels of felodipine were three times higher than expected. Bailey knew he was on to something.

It turned out that some compound specific to grapefruit inhibited the action of CYP3A4, an enzyme found in the wall of the intestine. This enzyme is part of the body’s detoxicating system and tackles intruders, such as medications. If its action is impaired, blood levels of these foreign substances can be expected to rise. Since CYP3A4 is known to be involved in the metabolism of numerous drugs, researchers suspected that felodipine would not be the sole medication to show a “grapefruit effect.” Indeed it was not. Various oral medications, ranging from heart-rhythm regulators and immunosuppressants to estrogen supplements and AIDS treatments, all interact with grapefruit juice. And the effect can last as long as 24 hours, meaning that drinking grapefruit juice at any time is contraindicated when taking drugs metabolized by CYP3A4. Since it isn’t completely clear which drugs fall into this category and which do not, and because of the known variation in CYP3A4 levels in different individuals, some experts suggest that grapefruit juice be avoided when taking any medication. Accordingly, many hospitals have taken grapefruit juice off the menu.

Grapefruit is not the only food to be involved in a drug-food interaction. Dairy foods can interfere with some antibiotics, broccoli can reduce the effect of anticoagulants, foods high in tyramine (aged cheese, red wine, soy sauce, sauerkraut, salami) can cause dramatic rises in blood pressure when coupled with antidepressants of the monoamine oxidase (MAO) inhibitor variety, and the absorption of digoxin (taken for congestive heart disease) is impaired by cereals such as oatmeal. And oh, all these interactions involve “natural” foods.

Read more

Citrus greening

citurs psyllidYou have probably never heard of the Asian citrus psyllid. But this insect, no bigger than the head of a pin, could be the reason that within a couple of years you will not be drinking orange juice or eating oranges from the U.S. The insect spreads a bacterium, which is harmless to humans and animals, but is devastating to citrus trees. Infected trees suffer from what has been called “citrus greening” because they produce green, misshapen fruit that is bitter and inedible. Once infected, the trees die within a few years. Since the insect clings to various parts of the tree, citrus greening can be spread by moving infected plant materials including bud wood, fruit and even leaves from one place to another. The disease has already killed millions of citrus plants in the southeastern United States and is threatening to spread across the country. There are no pesticides that are effective against the Asian citrus psyllid.

Since the infection is bacterial, one possibility is the use of antibiotics to try to curtail the problem. Interestingly, periwinkle plants are readily infected by the disease when exposed to lemon trees infected by citrus greening and respond well when treated with penicillin and some other antibacterial agents. Test are underway to see if these substances also work on infected citrus plants. The Madagascar periwinkle has already made a contribution to health in another arena. Vinblistine and vincristine isolated from the plant are used in chemotherapy.

Another approach involves genetic modification which could be helpful but comes with the baggage of public fear of the technology. Dr. Erik Mirkov, a Texas AgriLife Research plant pathologist, was actually interested in another disease known as citrus canker. He knew that some spinach proteins had antibacterial and anti-fungal properties and managed to insert the genes that code for these proteins into the DNA of citrus trees. The trees developed resistance to canker. As the problem of citrus greening became more and more important, he tested the spinach genes in citrus trees infected with the citrus psyllid. Early greenhouse tests looked good so field trials were begun and these also look hopeful.

But even if the technology pans out, the approval process is long and difficult. It’s expensive because it involves contracts with firms that do the actual testing with rats, bees, fish and maybe even songbirds It could take three to four years to complete, but it’s important of course to determine that the fruit produced from transgenic trees are safe to eat, especially by what are considered at-risk groups, which include infants, the elderly and those with compromised immune systems. The work is made easier by the fact that only proteins that are commonly eaten anyway are introduced into the crop. Saving citrus trees is not a minor issue and we need to explore all technologies that may play a role. Not only will the loss of the U.S. citrus industry have an effect on the availability and cost of citrus products, it will have a catastrophic fallout on the lives of citrus farmers and juice producers and thereby on the economy, especially of Florida.

Read more

Charcoal is one of the most important substances ever discovered

charcoalIt’s a killer. It’s a saviour. It’s also a trickster. It’s one of the most important substances ever discovered. It’s charcoal!

Burn any animal or vegetable matter with a limited supply of air, as is the case inside a wood pile, and you are left with charcoal, essentially carbon mixed with some mineral ash. The fact that charcoal burns better than wood was probably noted soon after man learned to control fire over a million years ago. The first use of charcoal for purposes other than providing heat was around 30,000 BC when cavemen used it as a pigment for drawing on the walls of caves.

Then around 4000 BC came a monumental discovery, probably by accident, when a piece of ore fell into a charcoal fire and began to ooze metal. When naturally occurring ores of copper, zinc and tin oxides are heated with charcoal, the carbon strips away the oxygen, leaving the pure metal behind. Alloying copper with tin forms bronze. The Bronze Age was followed by the Iron Age, characterized by the smelting of iron from iron oxide with charcoal. That same technology is still used today. But it wasn’t only through the smelting of metals that charcoal had an impact on history.

Sometime in the 9th century a Chinese alchemist discovered that blending charcoal with saltpeter (potassium nitrate) and sulphur resulted in a mixture that would combust readily. “Gunpowder” would eventually be used to create explosives that gave access to coal and minerals, making huge engineering achievements possible. Of course gunpowder also made possible the easier destruction of life, casting a dark shadow on charcoal.

Around 1500 BC, Egyptian papyri recorded the use of charcoal to eliminate bad smells from wounds, the first mention of a medical application of charcoal. By 400 BC, the Phoenicians were storing water in charred barrels on trading ships to improve its taste. It seems they had hit upon one of charcoal’s most important properties, the ability to bind substances to its surface, a phenomenon known as “adsorption.” That application lay more or less dormant until the late 18th century, when Europeans developed a taste for sugar. Raw sugar from sugar cane or sugar beets is tainted by coloured impurities that can be removed by passing sugar extract through beds of charcoal.

The rapid growth of the sugar refining industry led to a search for charcoal with improved adsorption properties and resulted in the development of “activated” charcoal, also referred to as “activated carbon.” In this process, carbonaceous matter such as wood, coal or nutshells is first heated in the absence of air, followed by exposure to carbon dioxide, oxygen or steam. This has the effect of increasing the surface area and establishing a network of submicroscopic pores where adsorption takes place. Later, it was determined that impregnation with chemicals like zinc chloride or phosphoric acid prior to heating improved the adsorption properties. Today, a variety of activated carbon products are available for use in various applications.

Activated charcoal is used in water filters, air purification systems, gas masks and even underwear. Yes, flatulence filtering undergarment for people suffering from various gastric problems really works. But in order to avoid flatulence escaping around the filter, the patient is recommended to stand with legs together and let the wind out slowly.

Because of its amazing adsorptive properties, activated carbon is a staple in emergency rooms. In cases of suspected drug overdose or poisoning, it is administered orally to bind the toxins before they have a chance to be absorbed into the bloodstream. It isn’t surprising that inventive marketers have absorbed this information and have started to roll out various foods and beverages containing activated carbon with promises of “detoxing.” “Black Magic Activated Charcoal” a “zesty lemon detox and purification elixir,” invites you to “come over to the dark side.” A very apropos invitation. Just what sorts of toxins are this beverage supposed to remove? And since activated carbon isn’t very specific in what it adsorbs, it is as likely to remove vitamins, polyphenols and medications as those unnamed toxins. Of course it is made with “alkaline water,” catering to the nonsense that cancer is caused by an acidic pH. Any alkaline water is of course immediately neutralized by stomach acid. Believe it or not, you can also get “activated carbon ramen noodles.” The only thing these will eliminate is your appetite.

Read more

Food Babe Lesson #2

vani hariI’m not sure my chemistry lesson for the Food Babe got through to her but many of you said that I should keep up the effort to teach her some science. Others said that it was like trying to teach an ant to crawl up a Teflon wall. Let’s give it another shot.

Vani, you posted a recipe for a smoothie, which is fine, but it was accompanied by this introduction:

“I include smoothie recipes like this as a regular part of this program because it’s one of the best ways to get greens in your diet, provide your body a rich source of chlorophyll on a daily basis, and ultimately is one of the key actions you can take to keep your body in an alkaline state to avoid disease!”

Chlorophyll is one of the most important compounds in the world because without it plants cannot photosynthesize and without plants there is no life. But humans are not plants; we do not photosynthesize and have no need for chlorophyll. Yes, there are some claims that chlorophyll in the diet can prevent some carcinogens, such as produced by high cooking temperatures, but there is no proper scientific evidence that this is so. But that is a minor point in comparison to your call for keeping the body in an alkaline state.

Alkalizing” the body is a nonsensical concept. The human body carefully maintains the pH of blood at about 7.35, which is slightly alkaline, or basic. This is also the pH of the cells in all our organs that depend on the blood supply for their nourishment. Should the pH drop below 7 or exceed 7.7 we are looking at a potentially catastrophic situation. Luckily, our blood constitutes a buffered system, meaning that any variation of pH is immediately compensated for. Should there be an increase in acids entering the bloodstream, we immediately start exhaling more carbon dioxide, which then reduces acidity. Should the blood start to alkalize, the lungs retain more carbon dioxide, which dissolves to form carbonic acid while the kidneys eliminate basic bicarbonate.

What all this means is that the pH of the blood cannot be altered by changing the diet. A change in diet can certainly alter the acidity of the urine but that is unrelated to the pH of the blood. Breads, cereals, eggs, fish, meat, poultry can acidify the urine while most fruits and vegetables tend to make it more alkaline. The idea of monitoring the pH of the urine to achieve optimal health by “balancing” the body’s acidity is senseless. Is it possible that some people feel better by making their urine more alkaline? That’s possible. If they switch from a heavy meat and cereal diet to one that features more fruits and vegetables they may feel better. But this has nothing to do with balancing the body’s pH.

Read more

« Older Entries
Blog authors are solely responsible for the content of the blogs listed in the directory. Neither the content of these blogs, nor the links to other web sites, are screened, approved, reviewed or endorsed by McGill University. The text and other material on these blogs are the opinion of the specific author and are not statements of advice, opinion, or information of McGill.