Category Archives: cold season

Feed a cold, starve a fever? Not so fast, according to Salk research

An apple a day keeps the doctor away is one of those cliches we have heard all our lives. So is, feed a cold, starve a fever.

The last time you had a stomach bug, you probably didn’t feel much like eating. This loss of appetite is part of your body’s normal response to an illness but is not well understood. Sometimes eating less during illness promotes a faster recovery, but other times—such as when cancer patients experience wasting—the loss of appetite can be deadly.

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Now, research from the Salk Institute shows how bacteria block the appetite loss response in their host to both make the host healthier and also promote the bacteria’s transmission to other hosts. This surprising discovery, published in the journal Cell on January 26, 2017, reveals a link between appetite and infection and could have implications in treating infectious diseases, infection transmission and appetite loss associated with illness, aging, inflammation or medical interventions (like chemotherapy).

“It’s long been known that infections cause loss of appetite but the function of that, if any, is only beginning to be understood,” says Janelle Ayres, assistant professor at Salk Institute’s Nomis Foundation Laboratories for Immunobiology and Microbial Pathogenesis.

A Salk Institute study shows how Salmonella blocks the appetite loss response in hosts to both make the host healthier and promote the bacteria’s survival and transmission

Mice orally infected with the bacteria Salmonella Typhimurium typically experience appetite loss and eventually become much sicker as the bacteria become more virulent—spreading from the intestines to other tissues in the body. Ayres’ team tested different conditions in the infected mice and found that sick mice that consumed extra calories despite their appetite loss actually survived longer. It turns out this survival wasn’t due to a more active immune response by well-fed animals (as measured by levels of the bacteria in the host). Instead, it was because the Salmonella weren’t spreading outside of the intestines and throughout the body when the mice ate more, which enabled the animals to stay healthy despite infection. Even more surprising, the Salmonella were acting on the intestine to try to suppress the appetite loss in the host.

The finding was initially puzzling: why would the bacteria become less virulent and not spread to other areas in the body when nutrients were more plentiful? And why would Salmonella actively promote this condition? It turns out the bacteria were making a tradeoff between virulence, which is the ability of a microbe to cause disease within one host, and transmission, which is its ability to spread and establish infections between multiple hosts.

“What we found was that appetite loss makes the Salmonella more virulent, perhaps because it needs to go beyond the intestines to find nutrients for itself. This increased virulence kills its host too fast, which compromises the bacteria’s ability to spread to new hosts,” explains Sheila Rao, a Salk research associate and the first author on the study. “The tradeoff between transmission and virulence has not been appreciated before—it was previously thought that virulence and transmission were coupled.”

When the host ate more and survived longer during infection, the Salmonella benefitted: bacteria in those mice were able to spread via feces to other animals and increase its transmission between hosts, as compared to bacteria in mice who didn’t eat and died sooner due to heightened bacterial virulence.

The researchers discovered that, to halt the appetite-loss response and boost transmission between hosts, Salmonella produces a molecule called SlrP, which blocks activation of an immune protein (cytokine) in the intestines. This cytokine typically communicates with the brain’s appetite center, called the hypothalamus, to prompt the host to lose its appetite during infection. The team found that mice infected with Salmonella that couldn’t make SlrP ate less food while infected, lost more weight and died faster than control mice.

Though the same gut-brain pathway tied to appetite loss exists in the human as in mice, Ayres cautions that infection responses are dependent on many factors and that whether eating—or fasting—during illness can improve one’s health will depend in large part on what the causative agent of the infection is. Her team is planning to search the human microbiome (the collection of bacteria that live in people’s bodies) to find other microbes that might have a similar effect on this pathway and explore those for new therapies tied to appetite loss and treating disease. The lab also wants to investigate whether drugs could be used to turn up or down the sickness-induced appetite-loss pathway that SlrP targets.

“Now that we’d identified this mechanism that regulates appetite, we want to turn it on the flip side and see if we can decrease appetite via this mechanism to help in cases of metabolic disease,” says Ayres.

The discovery also points to the tantalizing possibility of treating infectious diseases with approaches other than antibiotics, such as nutritional intervention. “Finding alternatives to antibiotics is incredibly important as these drugs have already encouraged the evolution of deadly antibiotic-resistant strains,” says Ayres. In the United States alone, two million people annually become infected with bacteria that are resistant to antibiotics and at least 23,000 people die each year as a direct result of these infections, according to the U.S. Centers for Disease Control.

Tony

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Cold weather tips – NIA

Regular readers know that I just turned 77 last week. While I enjoy robust good health at present that is not true of many of my fellow senior citizens. A lot of them don’t get out a lot and suffer from limited mobility.

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The National Institute on Aging (NIA) said that older adults can be particularly vulnerable in cold weather. The NIA offered the following ways to stay safe during the winter months. While these are directed at seniors many apply to any individual deciding to go out and brave the winter winds.

Try to stay away from cold places. Changes in the body that come with aging can make it harder for older adults to be aware of getting cold.

Check the weather forecasts for windy and cold weather. Try to stay inside or in a warm place on cold and windy days. If you have to go out, wear warm clothes including a hat and gloves. A waterproof coat can help you stay warm if it’s cold and snowy.

Wear several layers of loose clothing when it’s cold. The layers will trap warm air between them. Don’t wear tight clothing because it can keep your blood from flowing freely. This can lead to loss of body heat.

Ask your doctor how the medicines you are taking affect body heat. Some medicines used by older people can increase the risk of accidental hypothermia. These include drugs used to treat anxiety, depression, or nausea. Some over-the-counter cold remedies can also cause problems.

When the temperature outside has dropped, drink alcohol moderately, if at all. Alcoholic drinks can make you lose body heat.

Make sure you eat enough food to keep up your weight. If you don’t eat well, you might have less fat under your skin. Body fat helps you to stay warm.

As a Chicagoan, I have dealt with cold weather before in the blog as well as my daily life:

Don’t hibernate in cold weather – Harvard

Cold weather exercising tips

11 Cold weather exercise tips

Tony

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Use Vitamin C for a healthy immune system

It’s that time of year again, not just holiday season, but cold season. And, for many of us, it’s vitamin C season. As a person just getting over his Christmas cold, I was interested to learn more about vitamin C. Turns out it is a very powerful force for good health.

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Here’s what Marisa Moore, MBA, RDN, LD from the Academy of Nutrition and Dietetics as to say about it.

“Vitamin C, or ascorbic acid, is a water-soluble vitamin well known for its role in supporting a healthy immune system. Because your body cannot make vitamin C, it must come from the foods you eat every day. Continue reading

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Ayurveda and Colds: How to Avoid Them and What to Do When You Have One? — STAYING HEALTHY WITH AYURVEDA

I don’t understand Ayurvedic medicine nor all the terms in this post, but there are a lot of very useful suggestions here that we can use as we find ourselves fending off the attacks of winter in COLD SEASON.

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Our bodies are more susceptible to health problems when the seasons are changing because our body functions differently in each season. When it is hot outside, our agni (or digestive fire) automatically decreases. Thus during the summer months our digestive capacity is diminished. Once the outside temperatures begin to fall, our internal fires naturally start […]

via Ayurveda and Colds: How to Avoid Them and What to Do When You Have One? — STAYING HEALTHY WITH AYURVEDA

 

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Just what we need to learn in cold season ….

Cooking with Kathy Man

New research from Karolinska Institutet in Sweden shows that men who take vitamin C supplements regularly run a higher risk of developing kidney stones. The study, which is published in the scientific periodical JAMA Internal Medicine, did not however observe an increased risk between kidney stones and multivitamins – which contain lower concentrations of vitamin C.

The research is based on data from a large population-based study of men from Västmanland and Örebro counties, who were monitored for 11 years. A total of 23,355 men were identified who had no history of kidney stones and who took either no dietary supplements or supplements in the form of vitamin C only. During the study period, 436 of the participants developed kidney stones that required medical attention. The researchers then compared the risk of kidney stones in vitamin C-takers with that in men who did not take any supplements. The analysis was…

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