Food preservatives linked to obesity and gut disease

Mouse study suggests that emulsifiers alter gut bacteria, leading to the inflammatory bowel condition colitis

Chemicals known as emulsifiers are often added to processed foods such as ice cream. 

Artificial preservatives used in many processed foods could increase the risk of inflammatory bowel diseases and metabolic disorders, according to research published on 25 February in Nature. In a study done in mice, chemicals known as emulsifiers were found to alter the make-up of bacteria in the colon — the first time that these additives have been shown to affect health directly.

About 15 different emulsifiers are commonly used in processed Western foods for purposes such as smoothing the texture of ice cream and preventing mayonnaise from separating. Regulatory agencies such as the US Food and Drug Administration (FDA) rule that emulsifiers are “generally regarded as safe”, because there is no evidence that they increase the risk of cancer or have toxic effects in mammals.

But when immunologist Andrew Gewirtz at Georgia State University in Atlanta and his colleagues fed common emulsifiers carboxymethylcellulose and polysorbate-80 to mice, they found evidence that the chemicals affected the animals' health. Although their diet was not otherwise changed, healthy mice whose water contained the chemicals became obese and developed metabolic problems such as glucose intolerance. In mice genetically engineered to be prone to inflammatory gut diseases, emulsifiers also seemed to increase the severity and frequency with which the animals developed inflammatory bowel disease.

The most severe health effects were seen in mice that consumed the chemicals at a level similar to a person whose diet consists of only ice cream, says Gewirtz. But the researchers saw effects even at one-tenth of the concentration of emulsifiers that the FDA allows in a food product.

Colonic colonies

To understand why emulsifiers affected the health of mice, researchers analysed bacteria from the animals' colons. They found less diversity in the microbial species than in healthy mice, and found evidence that the microbes had migrated closer the cells lining the gut. Gewirtz and his colleagues suspect that the emulsifiers can break down the heavy mucus that lines the mammalian gut and prevents bacteria from coming into contact with gut cells. If this happens, the bacteria cause inflammation in the gut, which can also lead to changes in metabolism.

Gewirtz says that previous studies may have missed these links because newly developed food additives are tested in large swathes of the population, masking any subtle effects in people whose genetics or gut-microbe composition predispose them to these diseases. For regulators, he says, “the idea that a subset of the population may be sensitive isn’t on the radar.”

This lack of specificity could explain why nutritionists and public-health agencies are constantly revising their dietary guidelines — just this month, for example, an advisory council to the US government recommended eliminating guidelines on cholesterol consumption. “If you look over a 50-year perspective, you would see that the recommendations go back and forth, back and forth,” says immunologist Eran Elinav of the Weizmann Institute of Science in Rehovot, Israel. “No one is lying or cheating, many of these studies are well-designed studies, but they all look at large populations.”

Last year, Elinav and computational biologist Eran Segal, a colleague at the Weizmann Institute, found that artificial sweeteners such as saccharin can cause metabolic diseases such as obesity and diabetes by changing the make-up of bacteria in the gut in both mice and humans. They are now compiling a database of genetic and microbiome data from about 1,000 volunteers, measuring their metabolic response to different test foods. They hope that this will eventually allow nutritionists to make specific dietary recommendations for individuals based on these parameters.

Additive problems

Elinav and Segal hope to incorporate consumption of emulsifiers, sweeteners and other artificial additives into their study, but caution that there are many components to inflammatory and metabolic diseases. “This is for sure not the only driving factor” for inflammatory bowel disease, Elinav says.

Gewirtz says that many more human and animal studies need to be completed before regulatory agencies would consider changing how additives are approved — after all, removing preservatives from foods would cause them to rot sooner, posing a different health risk. He hopes to do a study in humans soon and is already collecting biopsies from surgery patients to study where different bacteria live in the colon.

But the findings have been enough to convince Gewirtz and co-author Benoit Chassaing, a microbiologist at Georgia State, to start checking the labels of the foods they buy, although both say they are not trying to eliminate emulsifiers entirely. It is not easy to find emulsifier-free food, Gewirtz says, and products marketed as 'organic' are just as likely to contain these agents. “When it comes to people making their own decisions, between our studies and others out there, it’s better to eat less processed food,” he says.

Food preservatives linked to obesity and gut disease

8:53 AM colon, diseases, emulsifiers, FDA, featured, food, food preservatives, obesity

Mad Cow Disease Still Menaces U.K. Blood Supply

Just as the measles outbreak in the U.S. shows what can happen when the public gets too complacent about a disease thought to be safely a thing of the past, so might the British public be letting down its guard too soon regarding an even more devastating illness: mad cow disease's human incarnation.

 donor gives blood in London in 2003. Blood banks in North America turn away potential donors who spent three months or more in the United Kingdom between 1980 and 1996 to minimize the risk of spreading the human form of mad cow disease.

The worry is that the disorder,variant Creutzfeldt-Jakob disease(vCJD), has left an unknown mark on the U.K. blood supply, and that a hidden population of carriers might lead to another wave of cases.

"For all we know, the storm may well be ongoing," noted the British Parliament's Science and Technology Committee in a report last July. They urged more precautions against vCJD in the blood supply.

vCJD, which first appeared in England in 1996, is a brain disorder linked to consuming meat from cattle infected by bovine spongiform encephalopathy (BSE), informally known as mad cow disease.

At first vCJD causes psychiatric symptoms such as depression and anxiety, and neurological symptoms such as difficulty walking. The brain then deteriorates rapidly, and death occurs a little over a year after the onset of symptoms. There is no cure.

New food supply safeguards in the U.K. and elsewhere have dramatically cut down the incidence of mad cow disease, and only a handful of new vCJD cases have emerged over the past decade. But the misshapen proteins, or prions, associated with vCJD likely can be transmitted through blood from an asymptomatic donor, which is what continues to worry public health officials.
 

Silent Carriers

At least three vCJD cases out of 229 worldwide since 1980 are believed to have been contracted via blood transfusion rather than by eating contaminated meat. To minimize risk, blood banks in North America for about 15 years have turned away potential donors who spent three months or more in the United Kingdom between 1980 and 1996.

For obvious reasons, this restriction is impossible to carry out in the United Kingdom, but the risk is still there. A study of appendix samples published last year found that 1 in 2,000 people in the U.K. might be carrying the prions linked with vCJD.

Why, then, has there been no major outbreak of mad cow disease in Great Britain? That's one of many questions that puzzle researchers including  neurologist R. G. Will, founder of theNational CJD Research & Surveillance Unit at the University of Edinburgh. At the rate of 1 in 2,000 carriers, he said, one would expect a "very large outbreak" of vCJD in the U.K., but "that simply hasn't happened." In the past 35 years, Great Britain has seen a total of 177 cases—and just one since 2012.

Nonetheless, "we should be cautious about variant CJD," said Will, "because we can't be sure that we have seen the last of either the primary epidemic or of secondary transmission through blood transfusion."

"100 Percent Fatal"

Will refers to the "primary epidemic"—the one that broke out in 1996—because some researchers believe there could still be people who were infected many years ago who simply haven't come down with symptoms yet.

With an incubation period that could stretch to decades, "it's hard to say this is the end of the outbreak and it's all over," according to Ryan Maddox, an epidemiologist with the U.S.Centers for Disease Control and Prevention(CDC).

If there are people who are carrying the agent of vCJD, "it may be years and years before we know exactly what their fate is going to be," Maddox said. "Hopefully, the fate will be that nothing ever happens. But we just don't know."

In the meantime, those same carriers can be donating blood, potentially adding danger to the supply. Officials have no good way to screen for this.

Creating a reliable way to test blood for the prions linked to vCJD would be a "major achievement," said Will. But "it's been a very, very difficult technical scientific challenge." In response to the Parliament's report from last summer, British government health officials promised in October to "explore the possibility" of carrying out further research on developing such a test.

Any resurgence of the human version of mad cow disease is likely to be relatively small, especially when compared to other blood-borne infections, such as HIV, which affects millions worldwide.

Still, the prospect of a new outbreak is scary considering that, as Maddox notes, once symptoms develop, the disease is 100 percent fatal.

"Even if there are just two cases in a given year, or four cases," he said, "you don't survive it."

Mad Cow Disease Still Menaces U.K. Blood Supply

8:47 AM blood tranfusion, diseases, health, MAD COW, Medicine

Phage Therapy -Drug resistant bacterial diseases

Phage Terapy gets revitalized

 

The century old virus treatment is on high interset on the increasing drug resistance bactereia. Reports says the rastic mutaion in bacterial genome againt the antibiotics and reserches are spending a lot of time and resource on developing new drugs each and every time to tackle the diseases.


Bacterio Phage

Now the thoughts of using the century old virus treatment- use of bacterio phages- phages are virus which infects on bacteria- to treat for bacterial diseases. bacteria — to treat infections. Phage therapy is still widely used in Russia, Georgia and Poland, but never took off elsewhere. Pages are viruses and peoples are afrid of viruses.

Now, faced with the looming spectre of antibiotic resistance, Western researchers and governments are giving phages a serious look. In March, the US National Institute of Allergy and Infectious Diseases listed phage therapy as one of seven prongs in its plan to combat antibiotic resistance. And at the American Society for Microbiology (ASM) meeting in Boston last month, Grégory Resch of the University of Lausanne in Switzerland presented plans for Phagoburn: the first large, multi-centre clinical trial of phage therapy for human infections, funded by the European Commission.

Previous lack of Western interest to clinicians’ preference for treating unknown infections with broad-spectrum antibiotics that kill many types of bacterium. Phages, by contrast, kill just one species or strain. But researchers now realize that they need more precise ways to target pathogenic bacteria, says microbiologist Michael Schmidt of the Medical University of South Carolina in Charleston. Along with the rising tide of strains resistant to last-resort antibiotics, there is growing appreciation that wiping out the human body’s beneficial microbes along with disease-causing ones can create a niche in which antibiotic-resistant bacteria can thrive. “Antibiotics are a big hammer,” Schmidt says. “You want a guided missile.”

Finding a phage for a bacterial target is relatively easy, Young says. Nature provides an almost inexhaustible supply: no two identical phages have ever been found. As a bacterium becomes resistant to one phage — by shedding the receptor on the cell surface that the virus uses to enter — the Eliava Institute researchers simply add more phages to the viral cocktails that patients receive. Kutateladze says that they update their products every eight months or so, and do not always know the exact combination of phages that make up the cocktail.

In initial trials, the researchers found that their phage could kill more than 99% of the E. coli cells that contained specific anti­biotic-resistance gene sequences, whereas it left susceptible cells alone. Giving the phage to waxworm larvae infected with resistant E. coli increased the worms’ chance of survival. The researchers are now starting to test the system in mice (human trials are a long way off).

Phge therapy never replaces antibiotics . But it definitly gives and added advantage over the drug resistance strains of bacteria.

Phage Therapy -Drug resistant bacterial diseases

4:07 PM antibiotic resistance, bacterio phage therapy, diseases, drug resistance, mutaion, virus