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Chemistry Lesson for The Food Babe…and everyone else #19

vani hariThe best treatment for people prone to swallowing woo is a dose of chemistry. And one of the wooiest ideas out there is the one about alkaline diets curing disease. Gives me a headache. So let’s start the discussion with a headache remedy, aspirin, or “acetylsalicylic acid.” As that name suggests, the compound is an acid and when it is absorbed into the bloodstream from the digestive tract it has an acidifying effect meaning that it lowers the pH of the blood. pH is a measure of acidity with values below 7 indicating an acidic solution and above 7 an alkaline one. Proper health requires that the pH of the blood be maintained in a narrow range, generally between 7.35 and 7.45 and to ensure that the value does not wander out of this range, our blood is equipped with a variety of compounds that can neutralize either excess acid or excess base. This makes blood a “buffer” solution, meaning that it resists large changes in pH.

The primary components of the buffer system are carbonic acid and sodium bicarbonate. Carbonic acid in the blood comes about when the carbon dioxide released from cells as they “burn” nutrients to produce energy reacts with water. Any excess base is neutralized by carbonic acid, whereas any excess acid is neutralized by sodium bicarbonate. The levels of carbonic acid are fine-tuned by the breathing rate. If respiration is very slow, carbon dioxide is not exhaled, carbonic acid builds up in the blood and the pH drops. Hyperventillation, on the other hand, causes loss of carbon dioxide, and since carbon dioxide is needed to form carbonic acid, levels of this acid drop and the pH rises. This is exactly what happens in response to an acetylsalicylic acid overdose. The aspirin causes blood pH to drop, and in response hyperventilation kicks in to raise the pH.

An influx of an acid such as aspirin, or of a large dose of an alkaline substance like baking soda, can affect blood pH, but the effect is temporary due to the blood’s rapid buffering action. There is no way to permanently alter blood pH, and in any case this would be highly undesirable because it would lead to severe complications and probably death. The reason for mentioning this is that there are all sorts of claims made by “alternative” practitioners about eating an “alkaline diet” or drinking alkaline water to change the blood’s pH in order to prevent cancer. This is based on laboratory experiments that have no relevance to a living body. When cancer cells are maintained in an acidic environment in a test tube they grow faster and chemotherapeutic drugs work more effectively in an alkaline environment. These conditions can be set up in a test tube, but not in the body. You cannot alter the acidity of the blood by any sort of diet.

The “alkaline” diet that is talked about is actually an “alkaline ash” diet that can affect the pH of the urine, but not the blood. This is determined by burning food and determining if the residue left is acidic or basic. While an alkaline diet can alter the pH of urine, it does not affect the blood. It isn’t a bad diet. It promotes the consumption of fruits, vegetables and nuts at the expense of meat, sugar, alcohol and caffeine, but the claim that this can reduce the risk of cancer is pure folly. There is absolutely no evidence that such a diet can support a sustained change in blood pH and there is no evidence of any clinical benefit. Testing the saliva or the urine with pH indicator paper is meaningless in terms of offering any clue about blood pH. None of this has stopped a variety of quacks from peddling their water alkalizers and miracle diets to cure cancer. Some even claim to cure diabetes. They are full of woo.

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Chemistry Lesson for The Food Babe…and everyone else #18

vani hariBaby carrots are everywhere. Office workers are snacking on them, men watching football games are reaching for them instead of for potato chips and they’re even showing up in children’s lunchboxes. Great! Carrots have no fat, they don’t need to be salted, and they’re loaded with beta carotene, a Vitamin A precursor. Where do these baby carrots come from? What is their lineage? Well that depends. Some baby carrots are just that. They’re pulled out of the ground when they are still small, before they develop a woody taste. The majority of the tiny carrots we snack on, however, are not baby carrots, but “baby-cut carrots.” The parents of these babies could be said to be a cutting machine and a peeling machine. They actually start out life as fully grown carrots, but end up being cut into 5 cm long pieces before being fed into a machine that grates off the outer layer and rounds off the ends.

These babies were the brainchild of Mike Yurosek, a California carrot farmer who got tired of consigning huge numbers of his carrots to feed for pigs and cows because they were too twisted or otherwise misshapen to sell to consumers.  In some cases as much as 70% of a crop ended up as animal feed. So Yurosek devised a way to salvage the ugly carrots by cutting and reshaping them into the appealing baby carrots. Beast to beauty, as it were. Yurosek managed to make three little carrots out of one big one, and at the same time, triple the price. Now, that is good business.

As often happens these days, when a product becomes popular, the Internet quacks decide to throw a monkey wrench into the works. Those little carrots are poisoning us, they say. The proof is the white discoloration that shows up on their surface! This is the “toxic” chlorine that was used to wash the little guys. Humbug! Sometimes the carrots are rinsed in a dilute solution of chlorine or chlorine dioxide to do away with bacteria, that much is true, but this isn’t absorbed by the carrots.

The white discoloration, known in the trade as “carrot blush,” is the result of two separate factors. Moisture loss from the surface of the carrot roughens the surface and causes light to be scattered, giving a white appearance. This can be reversed by moistening the carrot. Whitening can also occur when damage to cells on the surface due to abrasion releases an enzyme that causes molecules called phenols to join together to form lignin, a structural substance in plants. It too scatters light and gives a white appearance. This is not reversible. Neither of these whitening effects has anything to do with the safety of eating a carrot. The bottom line is that carrots are good for you, whitened or not. If some of those internet quacks ate more carrots, maybe they could see the truth better.

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Chemistry Lesson for The Food Babe…and everyone else #17

vani hariBack in the 1930s a flower merchant with a greenhouse full of carnations got worried when the weather forecast called for extremely cold temperatures. So he placed a kerosene burner in the greenhouse and confidently went to bed. When he woke up in the morning, he was devastated. The carnations had all withered and were unusable. This severe financial blow caused him to seek scientific advice but nobody seemed to know what had happened until the gases produced when kerosene burned were analyzed. One of the gases produced was ethylene, which turned out to be a plant hormone. This was the chemical, produced by plants, that stimulates the breakdown of chlorophyll, the synthesis of pigments like lycopene, the buildup of sugars and acids and the softening of plant tissue by the enzyme polygalacturonase.

When this was discovered, the solution to another mystery became apparent. When first harvested, lemons are often too green to be acceptable in the marketplace. In order to hasten the development of a uniform yellow color, lemon growers used to store newly-harvested lemons in sheds kept warm with kerosene stoves. The heat was believed to hasten ripening. But when one grower tried a more modern heating system, he found that his lemons no longer turned yellow on time. With the discovery of ethylene release from burning kerosene, this now made sense. The ripening process was triggered by heat, but by the small amount of ethylene gas given off by the burning kerosene.  Today some fruits and vegetables are picked when they are still green and are gassed to ripen them. Alarmists scare people by telling them that that their produce is being gassed with “chemicals.” What they don’t mention is that this is the same chemical that plants produce naturally during the maturing process.

Since the carnation tragedy of the 30s, a great deal has been learned about keeping carnations fresh. They are kept away from any other ethylene producing plants and are also treated with a preservative solution to kill bacteria which can attack the stem and block the channels that deliver water. Commercial preservative solutions contain about 3% sugar which serves as food, 200 ppm of 8-hydroxyquinoline citrate and silver thiosulphate (STS). A home solution can be made with half a tablespoon of sugar and one teaspoon of bleach in half a liter of water. That will serve well for carnations and roses. But just be sure you keep your flowers away from any ripening bananas or other fruits because you don’t want to experience an ethylene tragedy like the one that took place in the 1930s.

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Chemistry Lesson for The Food Babe…and everyone else #16

vani hari

Vitamin history

To take or not to take, that is the question often asked about vitamin supplements. Some experts suggest that a balanced diet provides all the vitamins we need, while others claim that a daily multivitamin pill provides nutritional insurance. Then there are those who allege that vitamins can both prevent or cure a variety of diseases while others point to studies that imply vitamins are linked with greater morbidity. Too much confusion to clear up in one short lesson. But the confusion about the term “vitamin” can be addressed. Indeed, it is a misnomer. Vitamins are “vital,” but they are not necessarily amines.

“Vitamin” derives from the Latin “vita” for life and “amine,” the name for a family of nitrogen containing organic compounds. But as it turns out, not all vitamins are amines. The very first one, isolated from rice hulls by biochemist Casimir Funk in 1912 was indeed an amine and was given the name “thiamine.” Funk thought that there likely were other amines essential to life that had to be supplied by the diet and suggested the term “vitamine” be used to describe them. He was right about the existence of other “vitamines,” but when it turned out that they were not all amines, the “e” was dropped from the name.

Funk’s discovery takes us back to the late nineteenth century when the mechanized rice mill was introduced in Asia . It produced attractive white rice, but it also produced a new disease that came to be called “beriberi”. In the native language of Sri Lanka, beriberi means “weakness”, and describes a condition of progressive muscular degeneration, heart irregularities and emaciation. Kanehiro Takaki, a Japanese medical officer, studied the high incidence of the disease among sailors in the Japanese navy from 1878-1883 and discovered that on a ship where the diet was mostly polished rice, among 276 men, 169 cases of beriberi developed and 25 men died during a nine-month period.  On another ship, there were no deaths and only 14 cases of the disease.  The difference was that the men on the second ship were given more meat, milk and vegetables.  Takaki thought this had something to do with the protein content of the diet, but he was wrong.

About 15 years later a Dutch physician in the East Indies , Christiaan Eijkman, noted that chickens fed mostly polished rice also contracted beriberi but recovered when fed rice polishings.  He thought that the starch in the polished rice was toxic to the nerves, but he was wrong.  And that’s when Casimir Funk entered the picture. The Polish-born biochemist determined that it wasn’t something that was present in white rice that was the problem, it was something that was absent, namely the outer coating, the rice “hulls.” Funk managed to show that an extract of rice hulls prevented beriberi and introduced the term “vitamine” for substances in food that could prevent specific diseases.

A short time later, E.V. McCollum and Marguerite Davis at the University of Wisconsin discovered that rats given lard as their only source of fat failed to grow and developed eye problems. When butterfat or an ether extract of egg yolk was added to the diet, growth resumed and the eye condition was corrected. McCollum suggested that whatever was present in the ether extract be called fat soluble “A,” and that the water extract Funk had used to prevent beriberi, be called water-soluble factor “B.” When the water-soluble extract was found to be a mixture of compounds, its components were given designations with numerical subscripts. The specific anti-beriberi factor was eventually called vitamin B1, or thiamine. These “vitamins” had a common function. They formed part of the various enzyme systems needed to metabolize proteins, carbohydrates and fats. Some of the compounds in Funk’s water extract eventually turned out to offer no protection against any specific disease and their names had to be removed from the list of vitamins. As other water soluble substances which were required by the body were discovered, they were added to the B vitamin list.

Other vitamins were subsequently identified and given the designations C, D and E in order of their discovery.  Vitamin K was so called because its discoverer, the Danish biochemist Henrik Dam, proposed the term “Koagulations Vitamin” because it promoted blood coagulation.  Are there still unrecognized vitamins?  Not likely.  Patients have now been successfully kept alive for many years through total parenteral nutrition ( TPN ) which involves using an intravenous formula that incorporates the known vitamins.

And what then about those daily vitamins that are so heavily advertised? They don’t kill and they don’t cure. But they may fill in some nutritional gaps in a less than ideal diet. And nobody really knows what an ideal diet is.

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Chemistry Lesson for The Food Babe…and everyone else #15

vani hari

Cause and Effect

Studies are the heart of science. But which studies do we take to heart? That is becoming more and more of a critical question as studies are being cranked out at a frenetic pace exploring every facet of our lives. On any given day we may hear about rosacea being improved by a kanuka honey preparation, cranberry juice helping to lower heart disease risk, olive leaf extract reducing inflammation, or fatty and sugary foods being linked to lower cognitive function, at least if you happen to be a mouse. And that’s not all. One can readily find dozens of other studies, ranging from how global warming may cause sex changes in lizards to the possibility that sodium octyl sulfosuccinate, a chemical used in some soft drinks to help mix the ingredients, may be linked to obesity. Or that consuming citrus fruits or their juices may increase the risk of melanoma.

The question is, what do we do with all this information? In some cases, as with the kanuka honey, the conclusion is simple. If you have rosacea, it is worth a try. But what is the take away message from the citrus fruit-melanoma study? Many newspapers reported on that one with headlines like “Drinking a glass of orange juice or eating a fresh grapefruit for breakfast may increase the risk of skin cancer.” Yes it may. Slightly. And only in combination with sun exposure. Let’s expose the details of this study.? Over a twenty-five year period some 100,000 male and female health professionals filled out questionnaires every two years about their diet, lifestyle, sun exposure and health status. Participants who drank more than a glass of orange juice a day, or ate fresh grapefruit more than three times a week, had an increased risk of melanoma. Of course, as we so often say in science, association cannot prove cause and effect. Wearing skirts doesn’t cause brea st cancer even though there is a strong association. In the case of citrus fruits, it is possible that people who live in sunnier climates have more access to citrus products and consume more of them. That would lead to an association with skin cancer without being the cause.

Statistics alone can never prove causality, but they can point researchers towards avenues to explore in search of a possible mechanism that might lead to a cause and effect relationship. Is there some such mechanism that may explain the melanoma connection? Possibly. Citrus fruits contain compounds called furocoumarins that are known to be photocarcinogenic, meaning that in combination with sunlight they can cause mutations in DNA , a prelude to cancer. Does this mean that we should give up drinking oran ge juice and eating grapefruit? No. Citrus fruits contain a number of compounds that have been linked with protection from cancer. And furocoumarins do not cause melanoma by themselves, only in combination with sun exposure. The take-away message then is to keep sipping that orange juice, but do it in the shade. And don’t forget the broad spectrum, SPF 30 sunscreen.

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You Asked: Why does a cooked onion taste sweet and how come cutting a cooked onion does not make the eyes water?

onionOnion chemistry is extremely fascinating and extremely complex! We’ve been intrigued by this vegetable ever since our prehistoric ancestors gathered and cooked wild onions. By the time of the First Egyptian Dynasty 5000 years ago, onions were widely consumed for flavor and for their supposed medicinal properties. At various times they have been associated with the prevention of colds, loosening of phlegm, correction of indigestion, inducement of sleep, stimulation of appetite, disinfection of wounds and the elimination of parasites from the digestive tract. In ancient times people believed that onions were a symbol of eternity because of the concentric circles that make up their structure. For this reason, onion shaped towers became popular in Russia and Eastern Europe; the idea was that these buildings would stand forever.

Onions may not make us live forever but some of their components may indeed have medical benefits in reducing cholesterol, blood pressure and perhaps even the risk of cancer. This is why their chemistry has received a great deal of attention. The smell produced by a cut onion is actually a form of chemical warfare the plant has evolved to ward off pests. When an insect attacks the bulb, tissue damage unleashes a sequence of chemical reactions resulting in the release of propanethial oxide, an irritating substance designed to repel the attacker. This reacts with moisture in the eyes to form sulphuric acid which is the stuff that makes our eyes water. Unfortunately, to the onion, attack by an insect or a sharp knife appears to be the same.

Frying the onion causes yet another reaction, resulting in the formation of bispropenyl disulfide which has a sweet smell and a sweet taste. Some of the harsher tasting compounds are also destroyed by the heat, explaining the change in flavor. Furthermore, we do not cry over cooked onions because heat destroys the enzymes that are needed for the formation of propanethial oxide. Also the cooking process drives off any volatile irritants.

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Book review: Monkeys, Myths, and Molecules, Separating fact from fiction, and the science of everyday life

monkeys, myths and molecules“Reading a Dr. Joe book is always a thrill and Monkeys, Myths, and Molecules is no exception. Dr. Joe’s writing style is comfortable, engaging and humorous. While he writes for a general audience, he does so with a chemical flair. Monkeys, Myths, and Molecules appeals to chemistry teachers for numerous reasons. It really is a perfect educational gift for a family member or friend. If it does end up being a gift, make sure to read it first.

In the food section, Dr. Joe brings into focus the discussion surrounding fat consumption, cholesterol and heart disease. He examines and explains numerous studies relating to diet, fat and fat type, carbohydrate intake as well as sugar intake and shows where the health issues lie. He is clearly an advocate for healthy eating, tending to advise against the many fads one sees in print and on television.”



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Chemistry Lesson for The Food Babe…and everyone else #14

vani hari“You Won’t Believe Where Silly Putty Is Hiding In Your Food.” So begins one of the Food Babe’s attempts to shock us about how the food industry is poisoning us. This time the target of the wild rant is the oil that McDonald’s and other fast food establishment use for frying. That’s where Silly Putty is lurking, apparently just waiting to gum up our insides. Except that it’s not. There is no Silly Putty in oil or in anything that we eat. What we have here is another example of classic vaniharism.

Frying oil does sometimes contain polydimethylsiloxane , a chemical with a name that twists Vani’s tongue and is therefore deemed to be dangerous. At a concentration of 2 parts per million it prevents the oil from foaming over. Polydimethylsiloxane is a “silicone” which is a general term for compounds that contain -Si-O-Si- atom groupings in their molecular structure. But the properties of silicones vary depending on their specific structure. To use an analogy, “alcohol” is a general term for compounds that have the –O-H grouping, but there is a huge difference in the toxicity of ethanol, CH3CH2OH, which is what we drink, and methanol, CH3OH, which is lethal if consumed.

Polydimethylsiloxane is a clear liquid that when reacted with boric acid changes into a solid that we know as Silly Putty. This happens because the long molecules of polydimethylsiloxane are linked together iby boron into a three dimensional array with totally novel properties. This “cross-linked” silicone polymer is not present in any food. And the polydimethylsiloxane that is present is inert and non-toxic. Furthermore, even if Silly Putty were present, it wouldn’t be a problem in terms of toxicity. Untold number of kids have smeared it all over their face and mouth with no consequence. Of course one of Vani’s favourite fright techniques is to connect some ingredient in our food supply to a non-food use and imply that it is therefore dangerous. Just imagine the fuse she would try to light on learning that the glycerol added to breakfast cereals as a humectants is also used to make nitroglycerine.

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