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When you look at your food, some ingredients are easy to see. For example, there is obviously milk in your cereal, cheese on your pizza and peanut butter on your toast.
But your meals are also filled with ingredients you can’t see. And you might be surprised to learn just how much those hidden items affect your health.
Salt is a perfect example of an ingredient that you might not notice, even when you eat a lot of it.
Sometimes, salt is obvious. You can see it on pretzels. You can taste it on french fries. And you can sprinkle it on green beans, straight from the shaker.
But it’s the salt we can’t see that concerns scientists most. For decades, doctors have warned patients that too much salt can be bad for their hearts. Still, most Americans continue to eat way too much salt, even when they try to avoid the salt shaker.
That’s because more than 75 percent of the salt we eat is hidden in restaurant meals, fast food and processed foods, such as spaghetti sauce from a jar, canned soup and frozen pizza. Often, you can’t even taste that the salt is there.
Heart trouble has long been considered a grown-up problem, and parents haven’t worried too much about the salt their kids eat. But new research suggests that salt is starting to affect kids — in their hearts, kidneys and waistlines.
Loading up on salt-filled potato chips, hot dogs and canned tuna today could also set young people up for even more health problems down the road.
“Most national heads of policy-making bodies in the United States and Canada and Great Britain are reaching the same conclusion,” says Lawrence Appel, professor of medicine at the Johns Hopkins University School of Medicine in Baltimore. “Reduce your salt intake.”
Straight to the heart
Salt is made up of two elements, or basic components: sodium and chlorine. When put in food or liquid, salt, also called sodium chloride, or NaCl, breaks into its two elements.
The chlorine part of salt isn’t that important. It’s the sodium that can stir up trouble.
We need a small amount of sodium to keep our muscles working and our nerves sending messages throughout the body. But the amount of sodium we actually need is really tiny: about 500 milligrams, or less than a quarter teaspoon of salt. A little bit goes a long way.
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Want salt with that?Some foods just cry out for extra salt, like these fries. That can make them a bad meal choice.Burke/Triolo
Dietary guidelines in the United States and elsewhere recommend that healthy adults consume no more than 2,300 milligrams of sodium a day. That’s about a teaspoonful of salt.
Kids ages 9 to 13 should eat no more than 1,500 to 2,200 mg of sodium a day. Younger kids should get even less.
But the average American eats about twice the recommended daily amount. This worries doctors because too much sodium can cause the body to produce more blood. To pump the extra blood, the heart has to work extra hard. This leads to a rise in blood pressure — a measurement of how stressed out the heart is. High blood pressure, also known as hypertension, often leads to heart disease. Heart disease is the leading cause of death in the United States and can lead to ailments like heart attacks.
“Ninety percent of adult Americans develop hypertension in their lifetimes,” Appel says. It’s a big problem.
You are what you eat
Salt isn’t the only cause of hypertension. Eating lots of junk food, weighing too much and exercising too little also contribute to high blood pressure. But a large number of studies suggest that salt is a major player.
Some of the most powerful strikes against salt come from a pair of studies that took place in the 1990s. The goal of the research was to figure out if what we eat affects blood pressure, and if so, how much.
As part of the studies, hundreds of adults ate exactly what researchers told them to. Called DASH, these studies lasted for months at a time.
The results showed a sizeable drop in blood pressure in people who ate extra fruits and vegetables, lots of whole grains, low-fat dairy products and only small amounts of red meat, sweet treats and fatty foods like fast food and donuts. Eating well, the researchers concluded, is good for your heart.
But blood pressure levels dropped even more when participants who followed the diet described above also lessened their salt intake. In the first DASH study, participants ate a relatively high level of salt — 3,300 mg a day. In the second DASH study, participants’ salt intake dropped to as low as 1,500 mg a day. The low-salt, healthy eating program became known as the DASH diet, and doctors now recommend it to both adults and kids.
“The DASH diet reduces blood pressure in the whole population,” says Eva Obarzanek, a registered dietician and research nutritionist with the National Heart, Lung, and Blood Institute in Bethesda, Md. Better yet, she says, the diet works “as much as any [blood-pressure] drug would.”
What’s more, studies from around the world show that hypertension and heart disease rates are lowest in places where people eat the least amount of salt. (In fact, the Yanomami Indians of South America eat very little sodium and have lower blood pressure readings than American 10-year-olds.)
And in a 2007 study, scientists turned up the first direct link between salt and heart disease. They found that cutting down on salt now can lower a person’s risk of heart disease 10 to 15 years in the future.
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Well dressed?Although most salad offerings, with the exception of olives and other pickled foods, tend to be low in salt, salad dressings can have plenty. Check out the sodium content on the label before splashing plenty on your veggies.Burke/Triolo
“The bottom line is that high sodium levels are definitely bad for you,” Obarzanek says. “It affects everybody. And it’s important even if you don’t have high blood pressure [now], because you’re likely to get it as you get older.”
Start thinking about salt now
Like most kids, you probably don’t spend much time worrying about heart disease. After all, hypertension tends to become more common as people reach middle age and older.
But doctors say it’s never too early to start thinking about your heart — or about salt.
Blood pressure has been going up over the past decade in children and teenagers in the United States and many European countries. And a kid with high blood pressure is more likely to become a grown-up with hypertension.
“It’s better to not have a lifelong exposure to high blood pressure,” Obarzanek says.
Cutting down on salt might help stop the cycle. In one recent study, researchers from the United Kingdom analyzed 10 trials involving nearly 1,000 kids. The trial results showed that lowering sodium intake by 40 to 50 percent led to a significant decrease in blood pressure, even in infants.
Reducing salt might also help combat childhood obesity, a growing public health problem. British researchers recently found that kids who eat less salt also drink fewer sugary soft drinks. Drinking less soda makes kids less likely to gain weight, become obese and develop high blood pressure.
And salt can affect more than just your heart and weight. A study published in October found that a growing number of kids in the U.S are suffering from an ailment called kidney stones. This painful condition used to mostly affect people in their 40s and older. Now, kids as young as 5 are getting it.
The kidneys are responsible for filtering salt out of the bloodstream. So researchers think that kids eating too much salt and not drinking enough water are partly to blame for the trend.
How to lick salt
If you’re like most people, cutting down on salt can be tough, says Gary Beauchamp, director of the Monell Chemical Senses Center in Philadelphia.
His research shows that when given larger and larger amounts of sodium, people want more and more of it. Even babies drink more formula when it’s saltier. That preference starts as early as 4 months old.
Getting used to eating less salt, on the other hand, can take months. And low-sodium food might taste gross at first when you’re used to highly salted versions.
The good news is that you can retrain your taste buds to prefer less salty food. And now is a good time to do it: Research shows that what you eat as a kid strongly influences what you’ll like as an adult. So, the more salt (or sugar, or even spices, such as hot chili powder) you eat now, the more likely you are to crave those ingredients later. And later, your heart might be weaker and less able to handle a heavy salt load.
“It’s an easy change to make at virtually no cost,” says Darwin Labarthe, director of the Division for Heart Disease and Stroke Prevention at the Centers for Disease Control and Prevention in Atlanta. “And it has an immense health impact.”
The best way to reduce the amount of sodium you consume, researchers say, is to make changes gradually. Start by sprinkling half as much salt on your dinner as you normally do. Switch to fresh foods instead of canned and bottled versions. And go easy on the condiments. Things like ketchup, soy sauce and salad dressing can carry far more sodium than you might expect.
You might also want to start reading nutrition labels. You may be surprised to find out that a serving of tomato sauce has more than 500 mg of sodium. And that there are 1,150 mg of sodium in a McDonald’s double cheeseburger, and more than 2,000 mg in many frozen meals.
“Kids today need to give salt the shake,” says David Grotto, a dietician and author in Chicago, “For overall health’s sake.”
Showing posts with label Esquire. Show all posts
Showing posts with label Esquire. Show all posts
Friday, May 1, 2009
Saturday, January 10, 2009
tandem 7.tan.0002 Louis J. Sheehan, Esquire
http://rpc.technorati.com/rpc/ping
Louis J. Sheehan, Esquire . Diversity ruled among the first American settlers. Within a relatively short time span, at least two groups of people trekked across a land bridge from Asia to Alaska and then went their separate ways, one down the Pacific Coast and the other into the heart of North America, a new genetic study suggests.
A team led by geneticist Antonio Torroni of the University of Pavia in Italy estimates that these separate migrations into the New World occurred between 17,000 and 15,000 years ago. http://LOUIS2J2SHEEHAN.US
Even more populations with distinct genetic signatures and languages may have crossed a now-submerged strip of land, known as Beringia, that connected northeastern Asia to North America within that relatively narrow window of time, the scientists also contend in a paper published online January 8 and in the Jan. 13 Current Biology.
“Whereas some recent investigators had thought that a single major population expansion explained all mitochondrial DNA variation among Native Americans, this new report revives earlier ideas about multiple expansions into the New World,” comments molecular anthropologist Theodore Schurr of the University of Pennsylvania in Philadelphia.
Torroni’s team analyzed entire genomic sequences of mitochondrial DNA, the genetic material in cells’ energy-generating units that gets passed from mothers to children. Genetic data came from Native American groups in North, Central and South America that had already provided blood samples for study. The researchers focused on the disparate geographic distributions of two rare mitochondrial DNA haplogroups — which are characterized by a distinctive DNA sequence derived from a common maternal ancestor — that still appear in Native Americans.
“Our study presents a novel scenario of two almost concomitant paths of migration, both from Beringia about 15,000 to 17,000 years ago, that led to the dispersal of the first Americans,” Torroni says.
If that hypothesis holds up, he adds, it suggests that separate groups of New World migrants founded prehistoric Native American tool traditions independently in eastern and western North America. http://LOUIS2J2SHEEHAN.US The new findings also raise the possibility that the first Americans spoke languages from more than one language family, in Torroni’s view. Linguists have debated for decades whether late–Stone Age migrants to the Americas spoke tongues from a single language family that would have provided a foundation for many later Native American languages.
Despite the new evidence, scientific consensus on how and when the New World was settled remains elusive. http://LOUIS2J2SHEEHAN.US
“Peopling of the Americas is a hard problem,” remarks geneticist Jody Hey of Rutgers University in Piscataway, N.J. “My guess is that it will be a couple more years before we have a good picture of what happened.”
Hey takes a skeptical view of the new study. Different present-day Native American populations display signature mitochondrial DNA patterns, so it’s not surprising that rare haplogroups would be unique to separate regions, he says. But Torroni’s analysis doesn’t explicitly address whether their genetic data more closely reflect a single migration, a pair of simultaneous migrations or some other pattern of population movements, in Hey’s view.
Some climate reconstructions suggest that an ice-free corridor from Alaska into North America wasn’t passable until around 12,000 years ago, Schurr says. If so, that creates a major roadblock for Torroni’s scenario of an inland migration at least 15,000 years ago.
Investigators also differ on how best to study ancient population movements using genetic data.
Two approaches currently dominate DNA-based attempts to explain the population movements and evolution of people and other animals, Hey notes. Some researchers track today’s geographic distribution of different haplogroups and generate tree diagrams that portray patterns of ancestry, as Torroni’s group did. Other investigators, such as Hey, use statistical methods to test whether genetic data fit simple models of how populations might have been structured.
In 2005, Hey took the model-based approach to examine mitochondrial DNA from northeastern Asians and Native Americans. He concluded that a single group of New World settlers, consisting of perhaps 70 fertile adults, crossed Beringia no more than 14,000 years ago (SN: 5/28/05, p. 339).
In this study, Torroni and his colleagues got different results by searching a large genetic database for mitochondrial DNA. The team found 55 unrelated individuals who displayed either of two rare Native American haplogroups, called D4h3 and X2a, identifying 44 instances of haplogroup D4h3 and 11 instances of haplogroup X2a.
Further analyses indicated that the D4h3 haplogroup spread into the Americas along the Pacific Coast, rapidly reaching the southern tip of South America. Estimated ages of D4h3 sequences from ChiIe are nearly as old as the estimated time of the Beringia crossing.
In contrast, haplogroup X2a crossed Beringia and spread through an ice-free corridor in what’s now western Canada, eventually clustering in the Great Lakes area, the new study suggests.
Examination of an additional 276 mitochondrial DNA sequences, all from unrelated people, representing the six haplogroups common in Native Americans indicated that those genetic types entered the Americas at about the same time as the two rare haplogroups did.
“Within a rather short period of time, there may have been several entries into the Americas from a dynamically changing Beringian source,” Torroni says.
Extensive mitochondrial DNA data have yet to be obtained for many Native American populations, Schurr cautions. Hence, precise age estimates don’t exist yet for the major New World haplogroups and their sub-branches. Such estimates are needed to check the veracity of competing scenarios of ancient migration to the Americas, including Torroni’s.
Such scenarios also include recent mitochondrial DNA studies that argued for a single founding group of New World migrants. One research team concluded that northeastern Asians reached Beringia as early as 40,000 years ago but had to wait for ice sheets to melt before entering the Americas at least 20,000 years later (SN: 2/16/08, p. 102).
A separate investigation, published online September 17 in PLoS ONE, concluded that migrants from northeastern Asia stayed in Beringia only a few thousand years before crossing into the New World about 16,000 years ago.
“The more we learn about this story, the more we realize that there is much more to understand about this segment of human history and migration,” Schurr says. Louis J. Sheehan, Esquire.
Louis J. Sheehan, Esquire . Diversity ruled among the first American settlers. Within a relatively short time span, at least two groups of people trekked across a land bridge from Asia to Alaska and then went their separate ways, one down the Pacific Coast and the other into the heart of North America, a new genetic study suggests.
A team led by geneticist Antonio Torroni of the University of Pavia in Italy estimates that these separate migrations into the New World occurred between 17,000 and 15,000 years ago. http://LOUIS2J2SHEEHAN.US
Even more populations with distinct genetic signatures and languages may have crossed a now-submerged strip of land, known as Beringia, that connected northeastern Asia to North America within that relatively narrow window of time, the scientists also contend in a paper published online January 8 and in the Jan. 13 Current Biology.
“Whereas some recent investigators had thought that a single major population expansion explained all mitochondrial DNA variation among Native Americans, this new report revives earlier ideas about multiple expansions into the New World,” comments molecular anthropologist Theodore Schurr of the University of Pennsylvania in Philadelphia.
Torroni’s team analyzed entire genomic sequences of mitochondrial DNA, the genetic material in cells’ energy-generating units that gets passed from mothers to children. Genetic data came from Native American groups in North, Central and South America that had already provided blood samples for study. The researchers focused on the disparate geographic distributions of two rare mitochondrial DNA haplogroups — which are characterized by a distinctive DNA sequence derived from a common maternal ancestor — that still appear in Native Americans.
“Our study presents a novel scenario of two almost concomitant paths of migration, both from Beringia about 15,000 to 17,000 years ago, that led to the dispersal of the first Americans,” Torroni says.
If that hypothesis holds up, he adds, it suggests that separate groups of New World migrants founded prehistoric Native American tool traditions independently in eastern and western North America. http://LOUIS2J2SHEEHAN.US The new findings also raise the possibility that the first Americans spoke languages from more than one language family, in Torroni’s view. Linguists have debated for decades whether late–Stone Age migrants to the Americas spoke tongues from a single language family that would have provided a foundation for many later Native American languages.
Despite the new evidence, scientific consensus on how and when the New World was settled remains elusive. http://LOUIS2J2SHEEHAN.US
“Peopling of the Americas is a hard problem,” remarks geneticist Jody Hey of Rutgers University in Piscataway, N.J. “My guess is that it will be a couple more years before we have a good picture of what happened.”
Hey takes a skeptical view of the new study. Different present-day Native American populations display signature mitochondrial DNA patterns, so it’s not surprising that rare haplogroups would be unique to separate regions, he says. But Torroni’s analysis doesn’t explicitly address whether their genetic data more closely reflect a single migration, a pair of simultaneous migrations or some other pattern of population movements, in Hey’s view.
Some climate reconstructions suggest that an ice-free corridor from Alaska into North America wasn’t passable until around 12,000 years ago, Schurr says. If so, that creates a major roadblock for Torroni’s scenario of an inland migration at least 15,000 years ago.
Investigators also differ on how best to study ancient population movements using genetic data.
Two approaches currently dominate DNA-based attempts to explain the population movements and evolution of people and other animals, Hey notes. Some researchers track today’s geographic distribution of different haplogroups and generate tree diagrams that portray patterns of ancestry, as Torroni’s group did. Other investigators, such as Hey, use statistical methods to test whether genetic data fit simple models of how populations might have been structured.
In 2005, Hey took the model-based approach to examine mitochondrial DNA from northeastern Asians and Native Americans. He concluded that a single group of New World settlers, consisting of perhaps 70 fertile adults, crossed Beringia no more than 14,000 years ago (SN: 5/28/05, p. 339).
In this study, Torroni and his colleagues got different results by searching a large genetic database for mitochondrial DNA. The team found 55 unrelated individuals who displayed either of two rare Native American haplogroups, called D4h3 and X2a, identifying 44 instances of haplogroup D4h3 and 11 instances of haplogroup X2a.
Further analyses indicated that the D4h3 haplogroup spread into the Americas along the Pacific Coast, rapidly reaching the southern tip of South America. Estimated ages of D4h3 sequences from ChiIe are nearly as old as the estimated time of the Beringia crossing.
In contrast, haplogroup X2a crossed Beringia and spread through an ice-free corridor in what’s now western Canada, eventually clustering in the Great Lakes area, the new study suggests.
Examination of an additional 276 mitochondrial DNA sequences, all from unrelated people, representing the six haplogroups common in Native Americans indicated that those genetic types entered the Americas at about the same time as the two rare haplogroups did.
“Within a rather short period of time, there may have been several entries into the Americas from a dynamically changing Beringian source,” Torroni says.
Extensive mitochondrial DNA data have yet to be obtained for many Native American populations, Schurr cautions. Hence, precise age estimates don’t exist yet for the major New World haplogroups and their sub-branches. Such estimates are needed to check the veracity of competing scenarios of ancient migration to the Americas, including Torroni’s.
Such scenarios also include recent mitochondrial DNA studies that argued for a single founding group of New World migrants. One research team concluded that northeastern Asians reached Beringia as early as 40,000 years ago but had to wait for ice sheets to melt before entering the Americas at least 20,000 years later (SN: 2/16/08, p. 102).
A separate investigation, published online September 17 in PLoS ONE, concluded that migrants from northeastern Asia stayed in Beringia only a few thousand years before crossing into the New World about 16,000 years ago.
“The more we learn about this story, the more we realize that there is much more to understand about this segment of human history and migration,” Schurr says. Louis J. Sheehan, Esquire.
Thursday, December 4, 2008
chemist 44.che.0001 Louis J. Sheehan, Esquire
http://rpc.technorati.com/rpc/ping
Lab and field tests hint that dairy whey, a lactose-rich by-product of the dairy industry, could be used to clean up underground water supplies tainted with the solvent trichloroethylene (TCE), an industrial degreaser.
Consuming TCE or inhaling its fumes can cause liver and kidney damage, affect heart function, and possibly cause cancer (SN: 5/29/99, p. 343: http://www.sciencenews.org/pages/sn_arc99/5_29_99/fob6.htm). The chemical is in groundwater at more than half of the Environmental Protection Agency's Superfund sites.
To treat the tainted groundwater, engineers often pump hydrogen-yielding substances such as sodium lactate into the ground, where they react with TCE by removing its chlorine atoms. That turns it into a relatively harmless hydrocarbon, says Elizabeth S. Semkiw, a chemist at Western Michigan University in Kalamazoo. http://louissheehan.bravejournal.com
Her team's tests indicate that a slurry of whey pumped into the ground may do the same trick, if sufficient numbers of bacteria are added. Whey-munching microbes generate lactate compounds as well as acetates, butyrates, and other substances that can strip chlorine atoms from TCE. http://louissheehan.bravejournal.com
In the lab, a whey-microbe mix eliminated a 10-parts-per-million concentration of the pollutant from simulated groundwater in less than 2 weeks, says Semkiw. Also, field tests showed that groundwater laced with TCE, after flowing through a subterranean curtain of whey, contained breakdown products of the chemical.
Further tests will assess whether remediation with whey is more cost-effective than the use of chemicals such as sodium lactate, says Semkiw.
Lab and field tests hint that dairy whey, a lactose-rich by-product of the dairy industry, could be used to clean up underground water supplies tainted with the solvent trichloroethylene (TCE), an industrial degreaser.
Consuming TCE or inhaling its fumes can cause liver and kidney damage, affect heart function, and possibly cause cancer (SN: 5/29/99, p. 343: http://www.sciencenews.org/pages/sn_arc99/5_29_99/fob6.htm). The chemical is in groundwater at more than half of the Environmental Protection Agency's Superfund sites.
To treat the tainted groundwater, engineers often pump hydrogen-yielding substances such as sodium lactate into the ground, where they react with TCE by removing its chlorine atoms. That turns it into a relatively harmless hydrocarbon, says Elizabeth S. Semkiw, a chemist at Western Michigan University in Kalamazoo. http://louissheehan.bravejournal.com
Her team's tests indicate that a slurry of whey pumped into the ground may do the same trick, if sufficient numbers of bacteria are added. Whey-munching microbes generate lactate compounds as well as acetates, butyrates, and other substances that can strip chlorine atoms from TCE. http://louissheehan.bravejournal.com
In the lab, a whey-microbe mix eliminated a 10-parts-per-million concentration of the pollutant from simulated groundwater in less than 2 weeks, says Semkiw. Also, field tests showed that groundwater laced with TCE, after flowing through a subterranean curtain of whey, contained breakdown products of the chemical.
Further tests will assess whether remediation with whey is more cost-effective than the use of chemicals such as sodium lactate, says Semkiw.
Wednesday, June 4, 2008
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