Friday December 6, 2019

Skin Exposure to UVB Radiation Can Alter Gut Bacteria in Humans

In a new clinical pilot study, researchers tested the effect of skin UVB exposure on the human gut microbiome

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It is likely that exposure to UVB light somehow alters Gut Bacteria in the immune system in the skin initially, then more systemically, which in turn affects how favourable the intestinal environment is for the different bacteria. Pixabay

Skin exposure to UVB (Ultra Violet-B) radiation from the Sun can alter the gut microbiome in humans — possibly via vitamin D which can help explain the protective role of UVB in inflammatory diseases like Multiple Sclerosis and Inflammatory Bowel Disease.

Sun exposure, vitamin D levels and the mix of bacteria in our gut are each associated with risk of inflammatory conditions like MS and IBD, said scientists from University of British Columbia.

Exposure to UVB in sunlight is well-known to drive vitamin D production in the skin, and recent studies suggest that vitamin D alters the human gut microbiome.

However, that UVB, therefore, causes gut microbiome changes, via vitamin D production, has so far been shown only in rodents.

In a new clinical pilot study, researchers tested the effect of skin UVB exposure on the human gut microbiome.

Healthy female volunteers were given three, one-minute sessions of full-body UVB exposure in a single week.

Before and after treatment, stool samples were taken for analysis of gut bacteria – as well blood samples for vitamin D levels.

Skin UVB exposure significantly increased gut microbial diversity, but only in subjects who were not taking vitamin D supplements.

“Prior to UVB exposure, these women had a less diverse and balanced gut microbiome than those taking regular vitamin D supplements,” reported Professor Bruce Vallance, who led the University of British Columbia study.

“UVB exposure boosted the richness and evenness of their microbiome to levels indistinguishable from the supplemented group, whose microbiome was not significantly changed”.

Published in Frontiers in Microbiology, the analysis suggests that vitamin D mediates the change — which could help explain the protective effect of UVB light in inflammatory diseases like MS and IBD.

Gut
Skin exposure to UVB (Ultra Violet-B) radiation from the Sun can alter the Gut microbiome in humans — possibly via vitamin D which can help explain the protective role of UVB in inflammatory diseases like Multiple Sclerosis and Inflammatory Bowel Disease. Pixabay

The largest effect was an increase in the relative abundance of “Lachnospiraceae” bacteria after the UVB light exposures.

This indicates that vitamin D at least partly mediates UVB-induced gut microbiome changes.

The study is not designed to show the exact mechanism by which the microbiome changes occur, but both UVB and vitamin D are known to influence the immune system.

READ MORE: Here’s How Lipid in Human Body Can Help to Control Diabetes

“It is likely that exposure to UVB light somehow alters the immune system in the skin initially, then more systemically, which in turn affects how favourable the intestinal environment is for the different bacteria,” suggests Vallance.

The results have implications for people who are undergoing UVB phototherapy, said scientists. (IANS)

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Start Checking Your Cholestrol Level from Mid-20s to Avoid Heart Disease: Study

Cholesterol is a fatty substance - a lipid - found in some foods and also produced in our liver

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Researchers analysed the data obtained from almost four lakh persons in 19 countries and found a strong link between bad-cholesterol levels and risk of Heart disease from early adulthood over the next 40 years or more. Pixabay

A study has said that people should get their cholesterol levels checked from their mid-20s as the readings can be used to calculate lifetime risks of Heart disease and stroke.

The study, published in “The Lancet”, is the most comprehensive yet to look at the long-term health risks of having too much “bad” cholesterol for decades, the BBC reported.

Researchers maintain that earlier the people take action to reduce cholesterol through diet changes and medication, the better.

Cholesterol is a fatty substance – a lipid – found in some foods and also produced in our liver. It is needed to make hormones like oestrogen and testosterone, Vitamin D and other compounds.

While High-density lipoprotein (HDL) cholesterol is “good” as it keeps the body healthy, Low-density lipoprotein (LDL) is “bad” as it can clog arteries.

Researchers analysed the data obtained from almost four lakh persons in 19 countries and found a strong link between bad-cholesterol levels and risk of cardiovascular disease from early adulthood over the next 40 years or more.

They were able to estimate the probability of a heart attack or stroke for people aged 35 and over, according to their gender, bad-cholesterol level, age and risk factors such as smoking, diabetes, height and weight, and blood pressure.

The BBC quoted the report’s co-author Stefan Blankenberg of the University Heart Center in Hamburg: “The risk scores currently used in the clinic to decide whether a person should have lipid-lowering treatment only assess the risk of cardiovascular disease over 10 years and so may underestimate lifetime risk, particularly in young people.”

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A study has said that people should get their cholesterol levels checked from their mid-20s as the readings can be used to calculate lifetime risks of Heart disease and stroke. Pixabay

Blankenberg told BBC: “I strongly recommend that young people know their cholesterol levels and make an informed decision about the result – and that could include taking a statin.”

However, he added, there is a danger that people could rely on statins rather than leading a health lifestyle and although they were usually well tolerated, studies had not been done on the potential side-effects of taking them over decades.

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British Heart Foundation medical director Nilesh Samani said: “This large study again emphasises the importance of cholesterol as a major risk factor for heart attacks and strokes.

“It also shows that for some people, taking measures at a much earlier stage to lower cholesterol, for example by taking statins, may have a substantial benefit in reducing their lifelong risk from these diseases.” (IANS)