From the Vaults – The Science of MSG

Editors note: To welcome any readers that may be coming to my blog from my recent post regarding GMOs on LIVESTRONG.COM, I’m reposting one of my earlier discussions about another misunderstood topic in food: monosodium glutamate, or MSG.

As discussed in last week’s article, some creative scientists are examining the changes in Hawaiian seafood menus over time for useful data about fishery abundance. If researchers were to study another set of menus, those of Chinese restaurants in the United States, they would find a similarly interesting trend: from the early 1970s onward, many menus began to advertise the absence of monosodium glutamate, or MSG, in their cuisine. The U.S. Food and Drug Administration, however, has labeled MSG as a “generally recognized as safe” food ingredient since 1959. A sudden change in public perception led to these changes, but the roots of that perception are surprisingly obscure.

Courtesy of closter1chinesefood.com

Although MSG was only formally discovered in the early 20th century by Japanese chemist Kikunae Ikeda, the compound from which it is derived, glutamic acid, is one of the 20 amino acids necessary for proteins (and therefore life itself). The body recognizes the importance of glutamic acid through the sense of taste in foods like asparagus, tomatoes, cheese and meat. Just as the tongue’s taste buds detect sodium chloride as salty, sucrose as sweet, or quinine as bitter, they register glutamic acid as its own unique taste, designated by Ikeda as “umami,” a Japanese word for “delicious” or “yummy” that is often translated as “savory.” MSG is simply glutamic acid that has been stabilized through the addition of sodium; for comparison, MSG contains one-third the amount of sodium per unit volume as table salt.

Asian cooking traditionally derived umami flavor from ingredients such as seaweed (from which Ikeda first isolated glutamic acid) and dried tuna, but by the 1950s, purified MSG was available to the United States as the seasoning Ac’cent. Restauranteurs and food processors were quick to adopt the ingredient as an inexpensive way to bolster the flavor of their products. No concerns were raised by the substance’s inclusion until 1968, when a Chinese-American doctor named Robert Ho Man Kwok reported feeling a number of ill effects after eating at Chinese restaurants in the United States.

As BuzzFeed’s John Mahoney outlines, Dr. Kwok hypothesized in the New England Journal of Medicine that his symptoms may have been “caused by the monosodium glutamate seasoning used to a great extent for seasoning in Chinese restaurants,” and after the New York Times covered the story, a flurry of experiments were conducted to confirm his suspicions. Many of these studies did report an association between high doses of MSG and symptoms such as headaches and flushing, but they lacked the proper scientific rigor of double-blind design (in which both the experimenter and subject do not know which treatment is being administered) or placebo controls.

Better designed experiments over the following decades failed to confirm the results of earlier research, and a comprehensive review by the Federation of American Societies for Experimental Biology concluded that were was no association between MSG and short- or long-term health issues in humans. Despite this research, a number of groups have continued to advocate about the perceived dangers of the compound, and MSG has been absent from baby food since 1969. Yet as the scientific consensus stands, one should feel no fear in enjoying a plate of egg foo young from a Chinese restaurant, even if the menu is silent about the presence of MSG.

A Drop of Value – Wine Additives

As alcoholic beverages go, wine would seem to be among the simplest to produce, requiring little more than grapes, water and time; after all, humans have been producing the potable for over 6,000 years. But the modern, industrial-scale wineries of makers such as E&J Gallo, the company behind the Carlo Rossi and Barefoot brands, have little in common with the Copper Age vessels of the earliest vintners—and their products also contain ingredients that would have astounded their Neolithic forefathers.

Holding tanks at the largest winery in the world, operated by E&J Gallo in Livingston, California. Courtesy of Wine Business.

Take, for example, the coloring agent known as “Mega Purple.” The substance, a thick concentrate of grapes from the “Rubired” cultivar, adds a rich redness and jammy sweetness to any batch of wine. Mega Purple is astoundingly potent: 200 milliliters is enough for an entire wine barrel of 119 liters (less than two-tenths of a percent of the finished product).  Although few winemakers openly admit to using the additive, anonymous industry sources estimate that nearly 25 million bottles per year contain some Mega Purple, including several ultra-premium brands.

While Mega Purple adds flavor, sulfur dioxide prevents it from being lost. The chemical acts as an antimicrobial and antioxidative agent, fighting the negative effects that can come from improper wine storage. Yeast naturally produce small amounts of sulfur dioxide during fermentation, around 10 parts per million, but winemakers often add more to ensure the quality of their products. However, high levels of the gas can cause some people to have allergic or sensitive reactions, including asthma, stomach upset and dizziness.

The speed of wine production has also increased thanks to chemical additives. Aging in oak barrels, a lengthy and expensive process, adds flavors known as aromatic compounds and is considered an integral part of making fine wines. When winemakers don’t have the time or money to spend, they can add these flavors directly through oak essence, a concentrate that imparts vanilla, spice and coconut aromas. While oak essence is certainly convenient, it can’t replace the other benefits of oak aging, such as tannin reduction and the improvement of clarity and color.

In response to these practices, a growing number of winemakers have begun to market additive-free wines. Consumer acceptance has been a challenge; without the benefit of added sulfur dioxide, for example, a wine can become murky or become spoiled in transport. But, as sommelier Hugues Lepin explains, there are some definite positives to additive-free production: “I’m often being asked by customers to choose a wine that won’t give them a hangover and I always choose a wine that’s been made with little sulphur dioxide.”

 

At the Peak – Nobel Prizes 2013

The Nobel Prize that attracted the most attention this year was likely the peace prize, awarded to the Organization for the Prohibition of Chemical Weapons (in a contest with women’s education advocate Malala Yousafzai, the youngest nominee in Nobel history) for its work to eliminate chemical munitions like sarin in Syria and other nations. But the three prizes for the hard sciences (physics, chemistry, and physiology or medicine) recognize equally impressive contributions in their respective fields.

The Nobel Prize medal, courtesy of Wikipedia.

This year’s Nobel Prize laureates in physics were Peter Higgs and Francois Englert, who shared the prize for their theoretical analyses of the particle that bears Higgs’s name. The Higgs boson’s importance derives from the way in which it confers mass on other “elementary” particles, such as quarks (the building blocks of protons and neutrons) and electrons. In essence, elementary particles travel through an invisible field of energy, called the Higgs field, which is filled with Higgs bosons; the bosons interact with the other particles, transferring the field’s energy into mass according to Einstein’s famous equation E=mc^2 (which states that energy and mass are equivalent). Although the two scientists predicted the particle in 1964, it wasn’t until the construction of the Large Hadron Collider in Europe that the results of high-energy particle smashing confirmed its existence in early 2013.

The Nobel Prize in chemistry was shared among Martin Karplus, Michael Levitt, and Arieh Warshel in acknowledgement for their foundational roles in the computer modeling of chemical reactions. Although treated with skepticism when first developed, computer models now allow scientists to determine exactly what happens at each step of a chemical process, which is vitally important for fields such as drug development. The three scientists created models that incorporated both the classical physics necessary to work with large-scale molecules and the quantum mechanics needed to simulate smaller molecules and reactions between compounds. With enough computing power, laureate Levitt predicts that chemists could simulate an entire living organism using a refined version of the models he helped develop.

The physiology or medicine prize was also a joint award, split between James E. Rothman, Randy W. Schekman
and Thomas C. Südhof for discovering the way in which cells direct the traffic of vesicles. Vesicles can be thought of as miniscule packages created by cells to contain “cargo” such as hormones and enzymes, and they are shipped to locations both inside and outside the cells that construct them. The laureates’ work focused on how vesicles are sent to the right place in the organism at the right time; Schekman’s research concerned the genetics of the process, while Rothman’s work uncovered the proteins that attached vesicles to their destinations and Südhof’s determined the timing of the deliveries. Taken together, their efforts provide major insight into a process that, if disrupted, can lead to diabetes and disorders of the nervous system.

No Hot Air – The Federal Helium Reserve

The government shutdown, as recently discussed on this blog, has vastly curtailed the activities of federal science agencies ranging from NASA to the Centers for Disease Control and Prevention (whose researchers are currently wringing their hands over being unable to track a new outbreak of salmonella from contaminated chicken). Yet one important scientific resource managed to escape the effects of the furloughs: on Sept. 27, Congress passed H.R. 527, the Helium Stewardship Act of 2013,  which ensures that the Federal Helium Reserve in Texas can continue to operate for the foreseeable future. While this is certainly good news for birthday parties everywhere, it’s also encouraging for the surprising amount of research and technology that depends on the noble gas.

A tethered helium balloon, courtesy of Aerophile SA

Helium is mined from underground deposits in association with natural gas, which makes Texas a natural location for the national supply. At up to 1.9 percent helium, Texan deposits are also richer in the gas than other deposits around the world. The federal government took control of all U.S. helium production in 1925, originally to ensure a sufficient supply of nonflammable gas for its military observation balloons and airships after the explosive crash of the hydrogen-lifted USS Roma in 1922 (15 years before the significantly more famous Hindenberg disaster). Since then, the reserve has evolved into a major provider of the gas for the U.S. and the world: 42% of the country’s helium comes from the facility, as does 30% of the world’s supply.

Less than one percent of the demand for helium comes from party balloons; much more important are uses that take advantage of helium’s properties as a coolant. Because the gas can be chilled to near absolute zero without solidifying, physicists use it to maintain the temperature of experiments that study the properties of matter under very cold conditions. Magnetic resonance imaging (MRI) machines depend on helium to maintain the frigid environment necessary for the operation of their superconducting wires. New designs for nuclear power plants call for helium coolant as a way to eliminate the need for steam, making the generation of power more efficient.

Other applications use helium because of its inert characteristics. High-temperature welders create a “shield” of helium over their work to prevent metals from oxidizing during the process. In industrial settings where leaking gas pipes can be dangerous, helium is a safe way to test for problems. Even some lasers use helium, in conjunction with neon, to provide a stable medium for the excitation of light.

The U.S. reserve contains over 10 billion cubic feet of helium, and remaining world supplies are estimated at 638 billion cubic feet. While these numbers sound impressive, current projections for helium use suggest that underground deposits of helium will be completely tapped out by 2052. Maintaining a stockpile of helium is a good start, but the government should also encourage the use of helium recapture systems that reduce losses. Until researchers figure out an inexpensive way to isolate helium from the atmosphere, the vital gas should be considered a nonrenewable resource.

Something in the Air – Sarin Gas and Syria

As I write this post, President Barack Obama and his advisers are likely in conference regarding military action against the regime of Syrian dictator Bashar al-Assad. The United States had previously declared that the use of “a whole bunch of chemical weapons” by Syrian forces would be considered a “red line,” a point at which more direct US intervention in the country’s civil war would be justified. A rocket attack conducted by Mr. Assad on Aug. 21, in which approximately 3,600 victims suffered neurotoxic symptoms and 355 were killed, is thought by many in the Obama administration to have crossed that line. Recent laboratory analysis of hair and blood samples from those killed in the attack suggests that the rockets indeed carried the chemical agent sarin, strengthening US resolve for action.

Sarin was first discovered in 1938 through an accident at the German chemical company I.G. Farben, whose scientists had been attempting to develop stronger pesticides. The compound’s toxicity arises from its similarity to acetylcholine, a molecule produced naturally in the nervous system.

Acetylcholine, courtesy of Wikimedia Commons

Acetylcholine is a neurotransmitter, a chemical released by a neuron to trigger a response in a target cell; in this case, acetylcholine is released from a motor neuron to trigger the contraction of a muscle fiber. Normally, an enzyme called acetylcholinesterase degrades acetylcholine after the chemical has delivered its message to the muscle, allowing the muscle to relax. Sarin acts by binding to this enzyme in the place of acetylcholine, preventing it from breaking down the neurotransmitter. Without this chemical “off switch,” muscles stay contracted, straining the body and disrupting normal functions.

Symptoms of sarin poisoning can begin within seconds of exposure to the chemical. As Time’s Alexandra Sifferlin explains, initial responses include “weakness, vomiting, diarrhea and irregular heart rates,” while heavy exposure can cause “convulsions, paralysis, loss of respiratory functions and even death.” The symptoms are treatable using the antidotes pralidoxime chloride and atropine, which chemically pry sarin out of its association with acetylcholinesterase and prevent it from binding to the muscle cells themselves, respectively. However, these medicines must be administered within minutes to several hours of exposure to be effective, as sarin binds further with the enzyme in a process called “aging” if left untreated.

Due to the debilitating effects of the gas, the possession and use of sarin has been outlawed by the Chemical Weapons Convention (CWC) of 1997, to which 188 nations (including the United States) are signatories. Even before the ratification of this treaty, sarin had only been used in a handful of attacks, the most notable of which were the strikes of late Iraqi dictator Saddam Hussein against Kurdish civilians and Iranian military targets throughout the 1990s. The use of sarin by the Syrian regime is therefore extremely troubling from both scientific and historic perspectives, and it is in the interest of peace for the world at large that the use of this agent not be allowed to continue.

Secret Ingredient – The Science of MSG

As discussed in last week’s article, some creative scientists are examining the changes in Hawaiian seafood menus over time for useful data about fishery abundance. If researchers were to study another set of menus, those of Chinese restaurants in the United States, they would find a similarly interesting trend: from the early 1970s onward, many menus began to advertise the absence of monosodium glutamate, or MSG, in their cuisine. The U.S. Food and Drug Administration, however, has labeled MSG as a “generally recognized as safe” food ingredient since 1959. A sudden change in public perception led to these changes, but the roots of that perception are surprisingly obscure.

Courtesy of closter1chinesefood.com

Courtesy of closter1chinesefood.com

Although MSG was only formally discovered in the early 20th century by Japanese chemist Kikunae Ikeda, the compound from which it is derived, glutamic acid, is one of the 20 amino acids necessary for proteins (and therefore life itself). The body recognizes the importance of glutamic acid through the sense of taste in foods like asparagus, tomatoes, cheese and meat. Just as the tongue’s taste buds detect sodium chloride as salty, sucrose as sweet, or quinine as bitter, they register glutamic acid as its own unique taste, designated by Ikeda as “umami,” a Japanese word for “delicious” or “yummy” that is often translated as “savory.” MSG is simply glutamic acid that has been stabilized through the addition of sodium; for comparison, MSG contains one-third the amount of sodium per unit volume as table salt.

Asian cooking traditionally derived umami flavor from ingredients such as seaweed (from which Ikeda first isolated glutamic acid) and dried tuna, but by the 1950s, purified MSG was available to the United States as the seasoning Ac’cent. Restauranteurs and food processors were quick to adopt the ingredient as an inexpensive way to bolster the flavor of their products. No concerns were raised by the substance’s inclusion until 1968, when a Chinese-American doctor named Robert Ho Man Kwok reported feeling a number of ill effects after eating at Chinese restaurants in the United States.

As BuzzFeed’s John Mahoney outlines, Dr. Kwok hypothesized in the New England Journal of Medicine that his symptoms may have been “caused by the monosodium glutamate seasoning used to a great extent for seasoning in Chinese restaurants,” and after the New York Times covered the story, a flurry of experiments were conducted to confirm his suspicions. Many of these studies did report an association between high doses of MSG and symptoms such as headaches and flushing, but they lacked the proper scientific rigor of double-blind design (in which both the experimenter and subject do not know which treatment is being administered) or placebo controls.

Better designed experiments over the following decades failed to confirm the results of earlier research, and a comprehensive review by the Federation of American Societies for Experimental Biology concluded that were was no association between MSG and short- or long-term health issues in humans. Despite this research, a number of groups have continued to advocate about the perceived dangers of the compound, and MSG has been absent from baby food since 1969. Yet as the scientific consensus stands, one should feel no fear in enjoying a plate of egg foo young from a Chinese restaurant, even if the menu is silent about the presence of MSG.