Acidification of the seas linked to climate change could threaten fisheries production and is already causing the fastest shift in ocean chemistry in 65 million years, a U.N. study showed on Thursday.
Production of shellfish, such as mussels, shrimp or lobsters, could be most at risk since they will find it harder to build protective shells, according to the report issued on the sidelines of U.N. climate talks in Mexico.
It could also damage coral reefs, vital as nurseries for many commercial fish stocks.
"Ocean acidification is yet another red flag being raised, carrying planetary health warnings about the uncontrolled growth in greenhouse gas emissions," said Achim Steiner, head of the U.N. Environment Programme (UNEP).
"Whether ocean acidification on its own proves to be a major or a minor challenge to the marine environment and its food chain remains to be seen," he said in a statement.
A UNEP booklet reviewing scientific findings about ocean acidification, caused by water soaking up greenhouse gases from the atmosphere, said that it adds to threats to food security that already include overfishing and pollution.
"It's the speed of change ... that is the cause of concern," said Carol Turley, of the UK Ocean Acidification Research Programme.
DINOSAURS
"We don't think it has been experienced by the marine environment for 65 million years," when the dinosaurs vanished, she said, presenting a booklet entitled "Environmental consequences of ocean acidification: a threat to food security."
About 25 percent of the world's emissions of carbon dioxide, the main greenhouse gas, are absorbed by the seas, where it converts to carbonic acid. The pH value of the oceans, a scale from alkaline to acidic, has fallen 30 percent since the Industrial Revolution in a shift to acidity.
"We are speaking about a threat especially to the shellfish industry," said Joseph Alcamo, the chief scientist of UNEP. Aquaculture production ranges from French mussels to shrimp in Thailand.
It would also damage coral reefs, and fish that swim around reefs. About a billion people worldwide rely on fish as their main source of protein.
There was evidence that acidification had other effects, for instance impairing the sense of smell of bright-colored clown fish and making it harder for them to avoid predators.
And there were other puzzling findings. Some adult lobsters were apparently increasing shell-building even though juveniles were less able to build healthy skeletons.
Saturday, December 04, 2010
Friday, December 03, 2010
Eating more seafood rich in omega-3 fatty acids appears to slow advanced macular degeneration in seniors
Dishing up fish and shellfish more often at meals could help some older adults protect their eyesight longer.
Eating more seafood rich in omega-3 fatty acids — such as oysters, crabs and tuna — appears to slow advanced macular degeneration, a common cause of age-related blindness, according to new research published in this month's Ophthalmology.
The findings are consistent with previous research suggesting omega-3 supplements and omega-rich diets protect vision in some people, says study author Bonnielin Swenor of the Wilmer Eye Institute at Johns Hopkins School of Medicine.
"Our study shows a dietary effect, that people who had the highest weekly intake of fish and shellfish high in omega-3 fatty acids were significantly less likely to have advanced disease," Swenor says.
The observational study included 2,390 participants ages 65 to 84 on Maryland's Eastern Shore. They were asked to complete a questionnaire about diet habits in the previous year, including how much fish and shellfish they ate. Then they were evaluated for macular degeneration.
Although all of the participants averaged at least one serving of fish or shellfish a week, 68 people who had advanced macular degeneration, including blood vessel problems and atrophy in the retina, were significantly less likely to consume high omega-3 fish and seafoods. That suggests a fish-rich diet helps vision, Swenor says. Another 153 had intermediate-stage disease and 227 had early stages, while 1,942 had no macular degeneration.
"It's an important piece of evidence in the omega-3 story," says Steven Schwartz, Ahmanson professor of ophthalmology at UCLA's Jules Stein Eye Institute. "It's biologically plausible that the protective effect is from the omega-3s, but it's important to keep in mind that there are potentially other factors at play — genetics, environment and unknowns."
"The fact that it's consistent with other published reports makes it more credible," Massachusetts Eye and Ear Infirmary retina specialist Ivana Kim says. She cautions that the small percentage of people in the study with advanced disease (3%) may lead to false conclusions.
Nixing tobacco, controlling blood pressure, eating leafy green vegetables and nuts, and seeing a retina specialist if you've already been diagnosed with macular degeneration are other lifestyle recommendations Schwartz says he offers patients. He cautions against self-dosing with omega-3 supplements, though.
"We don't recommend patients go out on their own and supplement like crazy. Talk with your ophthalmologist and get a personalized plan," Schwartz says.
Eating more seafood rich in omega-3 fatty acids — such as oysters, crabs and tuna — appears to slow advanced macular degeneration, a common cause of age-related blindness, according to new research published in this month's Ophthalmology.
The findings are consistent with previous research suggesting omega-3 supplements and omega-rich diets protect vision in some people, says study author Bonnielin Swenor of the Wilmer Eye Institute at Johns Hopkins School of Medicine.
"Our study shows a dietary effect, that people who had the highest weekly intake of fish and shellfish high in omega-3 fatty acids were significantly less likely to have advanced disease," Swenor says.
The observational study included 2,390 participants ages 65 to 84 on Maryland's Eastern Shore. They were asked to complete a questionnaire about diet habits in the previous year, including how much fish and shellfish they ate. Then they were evaluated for macular degeneration.
Although all of the participants averaged at least one serving of fish or shellfish a week, 68 people who had advanced macular degeneration, including blood vessel problems and atrophy in the retina, were significantly less likely to consume high omega-3 fish and seafoods. That suggests a fish-rich diet helps vision, Swenor says. Another 153 had intermediate-stage disease and 227 had early stages, while 1,942 had no macular degeneration.
"It's an important piece of evidence in the omega-3 story," says Steven Schwartz, Ahmanson professor of ophthalmology at UCLA's Jules Stein Eye Institute. "It's biologically plausible that the protective effect is from the omega-3s, but it's important to keep in mind that there are potentially other factors at play — genetics, environment and unknowns."
"The fact that it's consistent with other published reports makes it more credible," Massachusetts Eye and Ear Infirmary retina specialist Ivana Kim says. She cautions that the small percentage of people in the study with advanced disease (3%) may lead to false conclusions.
Nixing tobacco, controlling blood pressure, eating leafy green vegetables and nuts, and seeing a retina specialist if you've already been diagnosed with macular degeneration are other lifestyle recommendations Schwartz says he offers patients. He cautions against self-dosing with omega-3 supplements, though.
"We don't recommend patients go out on their own and supplement like crazy. Talk with your ophthalmologist and get a personalized plan," Schwartz says.
Thursday, December 02, 2010
Probiotics may have limited benefits for certain illnesses in children
A leading medical group says there's some evidence that probiotics, or "good" bacteria, may have limited benefits for certain illnesses in children.
But the group says the science isn't yet strong enough to advocate infant formulas containing probiotics. And probiotics shouldn't be given to children who are seriously ill.
That's according to a new American Academy of Pediatrics report published Monday in the journal, Pediatrics.
About 500 different bacteria live naturally in a healthy human's intestinal tract, and there's a growing understanding of the role they play in health. For years, companies have been making claims that their probiotic pills, yogurts, milks and juices help digestive health and the immune system.
The new report summarizes findings from high-quality scientific studies on some of the active ingredients in the products. The report says probiotics taken early during diarrhea from a viral infection may shorten the illness in otherwise healthy children.
And probiotics also may prevent diarrhea in children who are taking antibiotics, which can sometimes cause the condition.
On the other hand, more evidence is needed before AAP can recommend probiotics for constipation, irritable bowel syndrome or Crohn's disease. And there's not enough evidence for recommending probiotics in pregnant women or infants to prevent eczema or asthma.
Future research may find more benefits, the report says. And "prebiotics," which contain fiber and other nutrients that feed probiotic bacteria, also may someday prove helpful.
One warning: Children with compromised immune systems or who use intravenous catheters should not receive probiotics because serious infections have been reported.
The bacteria in the products are only helpful if they're alive, which isn't always the case.
"Consumers should keep in mind that a large percentage of organisms in a probiotic supplement may die before the product is even purchased and labels can be misleading or incorrect," said Dr. Tod Cooperman, president of ConsumerLab.com, which tests products and reports on their quality.
The company tested probiotic supplements last year. Two children's probiotics contained only 7% and 21% of the listed amounts. Cooperman suggested that products be stored in sealed containers out of heat, light and humidity. He said it's best to refrigerate them.
But the group says the science isn't yet strong enough to advocate infant formulas containing probiotics. And probiotics shouldn't be given to children who are seriously ill.
That's according to a new American Academy of Pediatrics report published Monday in the journal, Pediatrics.
About 500 different bacteria live naturally in a healthy human's intestinal tract, and there's a growing understanding of the role they play in health. For years, companies have been making claims that their probiotic pills, yogurts, milks and juices help digestive health and the immune system.
The new report summarizes findings from high-quality scientific studies on some of the active ingredients in the products. The report says probiotics taken early during diarrhea from a viral infection may shorten the illness in otherwise healthy children.
And probiotics also may prevent diarrhea in children who are taking antibiotics, which can sometimes cause the condition.
On the other hand, more evidence is needed before AAP can recommend probiotics for constipation, irritable bowel syndrome or Crohn's disease. And there's not enough evidence for recommending probiotics in pregnant women or infants to prevent eczema or asthma.
Future research may find more benefits, the report says. And "prebiotics," which contain fiber and other nutrients that feed probiotic bacteria, also may someday prove helpful.
One warning: Children with compromised immune systems or who use intravenous catheters should not receive probiotics because serious infections have been reported.
The bacteria in the products are only helpful if they're alive, which isn't always the case.
"Consumers should keep in mind that a large percentage of organisms in a probiotic supplement may die before the product is even purchased and labels can be misleading or incorrect," said Dr. Tod Cooperman, president of ConsumerLab.com, which tests products and reports on their quality.
The company tested probiotic supplements last year. Two children's probiotics contained only 7% and 21% of the listed amounts. Cooperman suggested that products be stored in sealed containers out of heat, light and humidity. He said it's best to refrigerate them.
Wednesday, December 01, 2010
Children who consistently eat lots of fruits and vegetables lower their risk of having stiff arteries
Children who consistently eat lots of fruits and vegetables lower their risk of having stiff arteries in young adulthood, according to research reported in Circulation: Journal of the American Heart Association.
Arterial stiffness is associated with atherosclerosis, which underlies heart disease. When arteries are stiff, the heart works harder to pump blood.
Researchers compared childhood and adulthood lifestyle factors -- including consumption levels of vegetables, fruit, butter and alcohol, as well as smoking and physical activity status -- with pulse wave velocity in young adulthood. Pulse wave velocity assesses arterial stiffness.
"When the heart beats, the blood's ejection causes a pulse wave, which travels along the wall of the arterial tree," said Mika Kahonen, M.D., Ph.D., senior study author and professor and chief physician for the Department of Clinical Physiology at Tampere University Hospital in Tampere, Finland. "The velocity of this pulse wave is dependent on the stiffness of the arterial wall; the stiffer the wall, the higher velocity. It is well known that the arterial stiffening process has a major role in the development of cardiovascular diseases.
"To the best of our knowledge, this is the first study looking at the associations between childhood lifestyle risk factors and pulse wave velocity in young adulthood."
The researchers examined lifestyle factors and measured arterial pulse wave velocity of 1,622 participants in the Cardiovascular Risk in Young Finns Study, which followed children ages 3 to 18 for 27 years. They found:
* A pattern of eating fewer vegetables in childhood was associated with higher pulse wave velocity as an adult. The association remained significant when adjusted for traditional cardiovascular risk factors such as high-density lipoprotein, or HDL, (good cholesterol) and low-density lipoproteins (bad cholesterol).
* The group with the persistent pattern of eating more vegetables and fruit from childhood to adulthood, had an average 6 percent lower pulse wave velocity compared to those who ate the least vegetables and fruits.
* The number of lifestyle risk factors (low vegetable consumption, low fruit consumption, low physical activity and smoking) in childhood was directly associated with pulse wave velocity as an adult. This association remained significant when adjusted for the number of lifestyle risk factors in adulthood.
"These findings suggest that a lifetime pattern of low consumption of fruits and vegetables is related to arterial stiffness in young adulthood," Kahonen said. "Parents and pediatricians have yet another reason to encourage children to consume high amounts of fruits and vegetables."
Among limitations of the study, researchers derived the data from a self-reported food frequency questionnaire of monthly consumption instead of daily, which could underestimate associations. The study also was limited to white European participants.
Arterial stiffness is associated with atherosclerosis, which underlies heart disease. When arteries are stiff, the heart works harder to pump blood.
Researchers compared childhood and adulthood lifestyle factors -- including consumption levels of vegetables, fruit, butter and alcohol, as well as smoking and physical activity status -- with pulse wave velocity in young adulthood. Pulse wave velocity assesses arterial stiffness.
"When the heart beats, the blood's ejection causes a pulse wave, which travels along the wall of the arterial tree," said Mika Kahonen, M.D., Ph.D., senior study author and professor and chief physician for the Department of Clinical Physiology at Tampere University Hospital in Tampere, Finland. "The velocity of this pulse wave is dependent on the stiffness of the arterial wall; the stiffer the wall, the higher velocity. It is well known that the arterial stiffening process has a major role in the development of cardiovascular diseases.
"To the best of our knowledge, this is the first study looking at the associations between childhood lifestyle risk factors and pulse wave velocity in young adulthood."
The researchers examined lifestyle factors and measured arterial pulse wave velocity of 1,622 participants in the Cardiovascular Risk in Young Finns Study, which followed children ages 3 to 18 for 27 years. They found:
* A pattern of eating fewer vegetables in childhood was associated with higher pulse wave velocity as an adult. The association remained significant when adjusted for traditional cardiovascular risk factors such as high-density lipoprotein, or HDL, (good cholesterol) and low-density lipoproteins (bad cholesterol).
* The group with the persistent pattern of eating more vegetables and fruit from childhood to adulthood, had an average 6 percent lower pulse wave velocity compared to those who ate the least vegetables and fruits.
* The number of lifestyle risk factors (low vegetable consumption, low fruit consumption, low physical activity and smoking) in childhood was directly associated with pulse wave velocity as an adult. This association remained significant when adjusted for the number of lifestyle risk factors in adulthood.
"These findings suggest that a lifetime pattern of low consumption of fruits and vegetables is related to arterial stiffness in young adulthood," Kahonen said. "Parents and pediatricians have yet another reason to encourage children to consume high amounts of fruits and vegetables."
Among limitations of the study, researchers derived the data from a self-reported food frequency questionnaire of monthly consumption instead of daily, which could underestimate associations. The study also was limited to white European participants.
Subscribe to:
Posts (Atom)
Posts
