The Global Fool

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Food Additives, Microbiota, and Inflammation
Mar27

Food Additives, Microbiota, and Inflammation

By Roberta Attanasio “For centuries, additives have served useful functions in a variety of foods. Our ancestors used salt to preserve meats and fish, added herbs and spices to improve the flavor of foods, preserved fruit with sugar, and pickled cucumbers in a vinegar solution. Today, consumers demand and enjoy a food supply that is flavorful, nutritious, safe, convenient, colorful and affordable. Food additives and advances in technology help make that possible.” But, are food additives safe? Results from a recent study show that some food additives known as emulsifiers can alter the composition and location of the gut microbiota — the diverse population of 100 trillion bacteria that inhabit the intestinal tract — thus inducing intestinal inflammation. This inflammation, in turn, promotes the development of inflammatory bowel disease (Crohn’s disease and ulcerative colitis) and metabolic syndrome — disorders that are often severe and debilitating and afflict millions of people. The ancient Greeks used the emulsifying power of beeswax in cosmetic products. Egg yolk was probably the first emulsifier ever used in food production back in the early 19th century. Emulsifiers are now added to bread, chocolate, ice cream, margarine, processed meat, and more. But why? Add oil to water and the two liquids will never mix. At least not until an emulsifier is added. Emulsifiers are molecules with one water-loving (hydrophilic) and one oil-loving (hydrophobic) end. They make it possible for water and oil to become finely dispersed in each other, creating a stable, homogenous, smooth emulsion. The study results show that, in a mouse model, two common emulsifiers — caboxymethylcellulose (CMC) and polysorbate-80 (P80) — not only change the composition of the gut microbiota, they also make the gut more porous. The altered microbiota has enhanced capacity to digest and infiltrate the dense mucus layer that lines the intestine — bacteria reach immune cells, thus inducing activation of inflammatory pathways and the development of severe inflammation. Such changes in bacteria trigger chronic colitis in mice genetically prone to this disorder, due to abnormal immune systems. In contrast, in mice with normal immune systems, emulsifiers induce low-grade or mild intestinal inflammation and metabolic syndrome, characterized by increased levels of food consumption, obesity, hyperglycemia and insulin resistance. Fergus Shanahan (University College Cork), who was not involved in the study, told Ed Yong: “This work cannot be ignored.” He doubted that most people would be significantly affected by occasionally eating foods with emulsifiers — but risk might change for those who have a genetic predisposition to inflammatory bowel disease, or who eat lots of processed foods. Andrew Gewirtz, senior author of the study, said in a press release: “We do...

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E-Cigarettes and Vaping May Cause Lung Damage and Impaired Immune Responses
Feb14

E-Cigarettes and Vaping May Cause Lung Damage and Impaired Immune Responses

By Roberta Attanasio A few months ago, Oxford Dictionaries announced “vape” as its international Word of the Year 2014 – language research conducted by their editors revealed that its use in 2014 had more than doubled compared to 2013 (and increased by 30-fold since 2012), mostly because of the rapidly growing popularity of electronic cigarettes and the expanding debate over their safety. Although e-cigarettes are portrayed as devices that can help adult smokers quit while providing a safe alternative to tobacco smoking, mounting evidence shows that these devices may cause considerable harm. Indeed, about two weeks ago, California health officials said that e-cigarettes represent a rising public-health risk that threaten to unravel progress made on tobacco by “re-normalizing smoking behavior” and luring a new generation into nicotine addiction. Electronic cigarettes, or e-cigarettes, are tobacco-free and vaporize liquid (also called e-liquid or e-juice) that contains nicotine, producing “faux” smoke or vapor. Because they don’t burn anything, e-cigarettes don’t release any smoke – therefore, users don’t “smoke”, they “vape.” In addition to nicotine, the e-juice typically contains vegetable glycerin, propylene glycol, and flavorings. There are several types of e-juices, each containing different flavorings – these flavorings make “vaping” especially appealing to young smokers who would not normally try tobacco. While nicotine addiction caused by vaping in young smokers is clearly a major public health issue, there are also public health concerns associated with toxic substances released by e-cigarette vapors. Indeed, e-cigarettes may likely become a toxic replacement for tobacco products. Results from a recent study (published in the scientific journal PLOSone) show that emissions from e-cigarettes damage lung cells. The damage is mostly caused by inflammatory responses and oxidative stress, which are known to represent key events in the development of chronic airway diseases. Some flavored e-juices – particularly those containing cinnamon – are more toxic than others. Irfan Rahman, lead author of the study, said in a press release: “Several leading medical groups, organizations, and scientists are concerned about the lack of restrictions and regulations for e-cigarettes. Our research affirms that e-cigarettes may pose significant health risks and should be investigated further. It seems that every day a new e-cigarette product is launched without knowing the harmful health effects of these products.” Results from an additional study recently published in the same journal confirm that vaping may cause potential deleterious health effects. Using a mouse model, the researchers showed that e-cigarettes compromise the immune system in the lungs and generate some of the same potentially dangerous chemicals found in traditional nicotine cigarettes. Thomas Sussan, lead author of this study, said in a press release: “E-cigarette vapor alone produced mild effects...

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Inflammation Drives Susceptibility to Anxiety and Depression
Nov28

Inflammation Drives Susceptibility to Anxiety and Depression

By Roberta Attanasio Stress and anxiety are part of life — but while a little bit of stress (good stress) may keep us active and alert, and sometimes even motivate us, the long-term type (bad stress) can have negative effects on our health.  Elevated blood pressure and heart disease are just some examples of the so-called “stress-related diseases”. In addition, chronic stress increases the risk of developing depression. Scientists have known for many years that stress, anxiety and depression are linked to the inflammatory response — our first line of defense against infectious microbes. The link is provided by some of the chemical messengers, or cytokines, involved in this response. Patients with major depressive disorder and post-traumatic stress disorder produce higher levels of the cytokine interleukin 6 (IL-6). Is depression responsible for the increased cytokine levels, or are the increased cytokine levels responsible for the development of depression? Results from a new study published in the scientific journal Proceedings of the National Academy of Sciences (November 11, 2014) help to answer this question. The study (Individual differences in the peripheral immune system promote resilience versus susceptibility to social stress) was carried out by researchers at the Icahn School of Medicine at Mount Sinai (and their collaborators), using mice exposed to social stress. The researchers measured levels of IL-6 in mice prior to and after exposure to “repeated social defeat stress” and stress induced by witnessing the defeat of another mice. In experiments that involve repeated social defeat stress, non-aggressive mice are repeatedly subjected to bouts of social defeat by a larger and aggressive mouse placed in the same cage. In experiments based on stress induced by witnessing, mice watch another mouse face a larger, more aggressive mouse through a clear divider — this type of stress is considered purely emotional. When exposed to social stress, some of the non-aggressive mice, the so-called susceptible mice,  develop a clear depressive-like syndrome, which is characterized by long-lasting deficits in social interactions. termed “social avoidance” — mice prefer to spend more time near an empty cage rather than near another mouse. The researchers found that IL-6 levels are higher in mice more susceptible to stress than in unstressed mice or in mice more resilient to stress. They also found that, in stress-susceptible mice, numbers of white blood cells that release IL-6 are higher than numbers in control groups. Moreover, the researchers found increased levels of IL-6 in two separate groups of human patients diagnosed with treatment-resistant major depressive disorder, thus validating the results obtained with mice.  In additional experiments, the researchers transplanted a group of mice with white blood cells lacking IL-6, and treated another group of mice with antibodies that block the production of IL-6. Then,...

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Chlorovirus ATCV-1, a Green Algae Virus, May Slow Human Brain Activity
Nov03

Chlorovirus ATCV-1, a Green Algae Virus, May Slow Human Brain Activity

By Roberta Attanasio Chlorella viruses, or chloroviruses, infect green algae, single-celled organisms present throughout the world in freshwater ecosystems such as lakes and ponds. Now, it seems that chlorovirues also infect humans, causing changes in cognitive functions — the processes by which information is perceived, registered, stored, retrieved, and used. In other words, chloroviruses influence the ability to acquire and use knowledge. These novel findings — published on line in the scientific journal Proceedings of the National Academy of Sciences (October 27, 2014) — confirm that viruses may be able to jump from one kingdom (plants) to another (animals), something that has been shown only in very few instances.  For the study (Chlorovirus ATCV-1 is part of the human oropharyngeal virome and is associated with changes in cognitive functions in humans and mice), the researchers used throat swabs collected from 92 adults without a psychiatric disorder or serious physical illness. The researchers found that 40 of these adults carried the genetic material of one of the chloroviruses — Acanthocystis turfacea chlorella virus 1, or ATCV-1 for short. They also found that the presence of ATCV-1 was associated with a modest but measurable decrease in cognitive functions. Such a decrease was not associated with age, sex, race, socioeconomic status, cigarette smoking, travel history, or place of birth. However, this first set of findings did not show “causality” — the ability of ATCV-1 to cause the observed decline in cognitive functions. Thus, the researchers infected mice with the virus. After several months, as expected, the infected mice exhibited signs of cognitive impairment. Moreover, the researchers found that, in both humans and mice, exposure to ATCV-1 was associated with decreases in performance on tasks calling for visual spatial abilities, which are important for everyday life — for example, when using a map or merging into high-speed traffic. Robert Yolken, one of the study’s authors, said in a press release: “This is a striking example showing that the ‘innocuous’ microorganisms we carry can affect behavior and cognition. Many physiological differences between person A and person B are encoded in the set of genes each inherits from parents, yet some of these differences are fueled by the various microorganisms we harbor and the way they interact with our genes.” The researchers speculate that the immune system might be involved in the cognitive decline associated with the presence of ATCV-1. In mice infected with the virus, they found changes in several pathways involved in antigen processing and immune cell functioning. These changes were located in the hippocampus, the region of the brain involved in emotions, learning and memory formation. About 35% of the mice mounted an immune response following infection. The researchers propose that a type of chemical messengers called proinflammatory cytokines...

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Sex Differences in the Immune Response to Vaccines
Feb11

Sex Differences in the Immune Response to Vaccines

By Roberta Attanasio Women and men respond differently to infectious microbes and vaccines – it is said, indeed, that the immune system of women is stronger than the immune system of men. Stronger or weaker, one thing is certain – men and women are not the same in terms of immune response. A few years ago, the journal Lancet Infectious Diseases published “ The Xs and Y of immune responses to viral vaccines” – a comprehensive article that clearly shows how the biological differences between sexes influence the immune response to vaccines, as for example the influenza, yellow fever and hepatitis vaccines. There are not many published studies on the same subject, though. The majority of scientists involved in vaccine research do not consider sex as a variable and, typically, vaccine trials are not designed to take into account the physiological differences that exist between men and women. If we had to take these differences into account, how would things change when vaccinating human populations? In the New York Times article “Do women need such big flu shots?” Op-Ed contributors Sabra Klein and Phyllis Greenberger provide an example related to one of the influenza vaccines: “Under the current guidelines, men and women are to get equal-sized doses of the H1N1 vaccine. Yet women’s bodies generate a stronger antibody response than men’s do, research shows, so less vaccine may be needed to immunize them. If we could give women a smaller dose, there would be more vaccine to go around. And we might also spare them the mild side effects that vaccines can cause, like pain at the injection site, inflammation and fever. All of these are more common in women than in men.” In 2010, the World Health Organization published “Sex, Gender and Influenza”, a report that “focuses on the different effects of seasonal epidemics, pandemics and localized outbreaks of influenza on males and females including pregnant women.” The report concludes that “significantly more research is required to gain a more complete understanding of the complex and varied effects of sex and gender on influenza infection and vaccination, and underscores the need to consider their interplay with any infectious disease of global concern.” However, there are still large gaps in our understanding of how sex differences influence the immune response to vaccines and not enough research is done to fill these gaps. May be, step by step, we’ll get there. Meanwhile, here is one of the steps – a new study found that high levels of testosterone make the immune response to the flu vaccine go south. The study – “Systems analysis of sex differences reveals an immunosuppressive role for...

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