How Gut Bacteria Impacts Obesity, Allergies, Happiness and More

From- https://shangshuiw.wordpress.com

A growing body of research has shown that the teeming populations of gut bacteria within us have evolved complex connections that can affect our body’s basic functions — from metabolism to sleep to mood.

Changes in the makeup of the gut bacteria in the human digestive system have been associated with a growing number of diseases.

It’s important to remember, though, that the science is still young and evolving.

Here we highlight the most intriguing of the cutting-edge studies.

Healthy Heart

Some of the many beneficial compounds that certain gut bacteria produce for us are carotenoids—antioxidants that are believed to protect against stroke and angina.

In a 2012 study in Nature Communications, researchers in Sweden compared the gut microbiome of stroke patients to that of healthy subjects and found that there were more carotenoid-­producing gut bacteria in healthy participants.

Stanley Hazen, M.D., Ph.D., and his team at the Cleveland Clinic have been looking at a variety of ways microbes play a role in heart disease.

For example, when certain gut bacteria metabolize lecithin (abundant in egg yolks) and ­carnitine (a compound in red meat), it boosts compounds in the blood that are linked to an increased risk of heart attack and stroke. Remove the bacteria and the risk-causing compounds vanish even ­after eating those foods.

Allergies Denied

Researchers in Copenhagen reviewed the medical records and stool samples of 411 children for 6 years and found that those who had the least diverse colonies of gut bacteria as infants were more likely to develop some types of allergies.

Trim Weight

A growing body of studies indicates that obese people tend to have a much lower diversity of gut bacteria — up to 40 percent less — than people with a healthy weight. And gut microbes may be responsible for those lean or plump traits: several studies with mice have found that transferring gut microbes from obese mice (or from obese humans) into non-­obese mice, leads the non-obese mice to gain weight.

In turn, adding gut bacteria from lean mice into heavy ones causes the chubby mice to lose weight on a high-fiber, low-fat diet. Researchers believe different bacteria metabolize food differently, which could affect how much your body absorbs.

A 2013 study in the Proceedings of the National Academy of Sciences suggests certain gut microbes may help lower blood pressure.

Researchers found that by-products produced by certain gut bacteria activated a specific kind of cell receptor in blood vessels that lowers blood pressure. More bacteria equals more by-products, which equals healthier blood pressure.

Fight Cancer

A robust and diverse gut microbiome may help certain chemotherapies work better. French researcher Laurence Zitvogel, M.D., Ph.D., and his colleagues observed that gut bacteria in mice encouraged immature immune cells in the lymph nodes to develop into tumor-targeting T-cells.

In contrast, when mice were treated with antibiotics (which wipes out bacteria) before begin­ning chemotherapy, the chemotherapy was less effec­tive. The researchers ­believe the gut bacteria help prime the immune system to respond to chemotherapy.

Some microbes may be associated with colon cancer. University of Michigan researchers exposed two groups of germ-free mice — essentially mice with sterile colons — to a known carcinogen.

One group then received gut bacteria from mice with colon cancer and went on to develop twice the number of tumors than the other group who got gut bacteria from cancer-free mice. The researchers narrowed down the microbial families associated with colon cancer and one included Prevotella.

People with inflammatory bowel disease are at higher risk of developing ­colon cancer than the general population. Researchers have thought that the main culprit is overactive immune cells, which release DNA-damaging molecules. 

Now new findings in Science suggest that overactive immune cells also may be causing an imbalance in your gut bacteria — encouraging E. coli strains that produce cancer-causing toxins.

Relaxed & Happy

There’s something to be said for “gut feelings.”

Gut bacteria produce hundreds of different neurotransmitters, including up to 95 percent of the body’s supply of serotonin, a mood and sleep regulator. Serotonin also controls movement within the intestines.

Our gut is said to be our “second brain” in part because the vagus nerve is a major communications highway that stretches from the brain to various points along the intestinal lining; communication travels in both directions.

One Lactobacillus species, for example, sends messages from the small intestine to the brain along this nerve: in a study led by John Cryan, Ph.D., a neuroscientist at University College Cork in Ireland, anxious mice were dosed with a proprietary strain of Lactobacillus rhamnosus.

Those rodents then had lower stress hormone levels and an increase in brain receptors for a neurotransmitter that’s vital in curbing worry, anxiety and fear. The effects were similar to those of Valium.

According to another study, when mice had this bacteria in their gut, they showed less depressive behavior. Whatever bacteria may be responsible for “feeling good,” it appears they can be acquired: a recent experiment moved gut bacteria from fearless mice into anxious mice. The new bacteria sparked a personality change, making timid mice more gregarious

Dan Littman, M.D., Ph.D., a microbiologist at the NYU School of Medicine, led a study that found an association between the gut bacteria Prevotella copri and the onset of rheumatoid arthritis, an autoimmune disease of the joints. While the connection was significant, it’s not clear which comes first: the bacteria or RA.

However, other animal studies, Littman says, have clearly shown that gut microbes play a role in causing autoimmune diseases. One of these, published in 2013 in the journal Science, showed 75 percent of female mice at risk of autoimmune type 1 diabetes were protected against the disease when they were given gut bacteria from healthy mice.

Manage Crohn’s

A large study out of Massachusetts General Hospital involving more than 1,500 patients recently reported a connection between gut microbes and Crohn’s disease (an inflammatory bowel disease that can affect any part of the GI tract, but typically the intestines).

In addition to having less diversity, Crohn’s patients had fewer bacteria known to quell inflammation and more bacteria that cause inflammation.

Interestingly, those who received the standard antibiotic treatment for Crohn’s had a microbe mix that was even more out of balance. Another study found that when Crohn’s patients were given a prebiotic fiber supplement each day, disease symptoms decreased significantly.

Vitamin D Heals Damaged Hearts

Vitamin D supplements may help people with diseased hearts, a study suggests.

A trial on 163 heart failure patients found supplements of the vitamin, which is made in the skin when exposed to sunlight, improved their hearts’ ability to pump blood around the body.

The Leeds Teaching Hospitals team, who presented at a meeting of the American College of Cardiology, described the results as “stunning”.

The British Heart Foundation called for longer trials to assess the pills.

Vitamin D is vital for healthy bones and teeth and may have important health benefits throughout the body but many people are deficient.

No safe way to suntan – warning

The average age of people in the study was 70 and, like many people that age, they had low levels of vitamin D even in summer.

“They do spend less time outside, but the skin’s ability to manufacture vitamin D also gets less effective [with age] and we don’t really understand why that is,” said consultant cardiologist Dr Klaus Witte.

Patients were given either a 100 microgram vitamin D tablet or a sugar pill placebo each day for a year.

And researchers measured the impact on heart failure – a condition in which the heart becomes too weak to pump blood properly.

The key measure was the ejection fraction, the amount of blood pumped out of the chambers of the heart with each beat.

In a healthy adult, the figure is between 60% and 70%, but only a quarter of the blood in the heart was being successfully pumped out in the heart failure patients.

But in those taking the vitamin pills, the ejection fraction increased from 26% to 34%.

Dr Witte told the BBC News website: “It’s quite a big deal, that’s as big as you’d expect from other more expensive treatments that we use, it’s a stunning effect.

“It’s as cheap as chips, has no side effects and a stunning improvement on people already on optimal medical therapy, it is the first time anyone has shown something like this in the last 15 years.”

The study also showed the patients’ hearts became smaller – a suggestion they are becoming more powerful and efficient.

In the UK, people over 65 are advised to take 10 microgram supplements of the vitamin.

However, Dr Witte does not think high-dose vitamin D should be routine prescribed just yet.

He told the BBC: “We’re a little bit off that yet, not because I don’t believe it, but data have shown improvements in heart function, they may show improvements in symptoms and we now need a large study.”

It is also not clear exactly how vitamin D is improving heart function, but it is thought every cell in the body responds to the vitamin.

Most vitamin D comes from sunlight, although it is also found in oily fish, eggs and is added to some foods such as breakfast cereals.

Prof Peter Weissberg, from the British Heart Foundation, cautioned that the patients seemed no better at exercise.

And added: “A much bigger study over a longer period of time is now needed to determine whether these changes in cardiac function can translate into fewer symptoms and longer lives for heart failure patients.”

Don’t Feed Babies a Ton of Rice Cereal, Says FDA

Millie-  say don’t feed them ANY grains at all, especially the first year!

Rice cereal is a popular first food for babies. It’s also kind of high in arsenic, says the Food and Drug Administration, so if your kid gets a steady rice cereal diet, it’s time to diversify.

Plants pick up minerals from the soil they’re grown in. Rice is especially good at picking up arsenic. It doesn’t matter if the rice was grown organically or not; this is a blanket warning for rice in general. Baby rice cereal is getting the most attention because some babies eat a lot of it. It’s typically fortified with iron and other nutrients, so pediatricians love to recommend it. The FDA says it’s still fine in small quantities, but don’t go crazy:

Rice cereal fortified with iron is a good source of nutrients for your baby, but it shouldn’t be the only source, and does not need to be the first source. Other fortified infant cereals include oat, barley and multigrain.

Pregnant women, likewise, should avoid relying heavily on rice in their diet. At very high levels, arsenic can interfere with a baby’s brain development. Brown rice carries more arsenic than white rice, and some rice-growing parts of the world have more arsenic than others, Deborah Blum writes at Undark. Arsenic has also been found at high levels in organic brown rice syrup, which is used as a sweetener.

Currently, the FDA does not set a limit on the amount of arsenic that can be in rice products. In a recent analysis, they sampled infant rice cereals and other foods. About half (53%) had levels above the European Union’s cutoff of 100 parts per billion. Non-rice foods were all below that level. The report doesn’t name brands, but baby food maker Gerber quickly wrote a letter to families pointing out that their rice cereals were all below 100 ppb.

The FDA has more information on arsenic in rice here.You can read their recent warning to parents at the link below.

For Consumers: Seven Things Pregnant Women and Parents Need to Know About Arsenic in Rice and Rice Cereal | FDA via Undark

Fast Food May Expose Consumers to Phthalates

(Reuters Health) – People who eat a lot of fast food may be exposed to higher amounts of certain chemicals in plastics that are believed to disrupt human hormones and possibly cause cancer, according to a U.S. study.

Researchers found that people who eat the most fast food have up to 39 percent more of two industrial chemicals called phthalates in their blood than those who eat less, or no fast food at all.

“We found a significant association suggesting that the more fast food someone eats, the higher the levels of two particular phthalates known to be used in food packaging and food contact material,” said lead author Ami R. Zota of the department of environmental and occupational health at the Milken Institute School of Public Health at George Washington University in Washington, D.C.

Phthalates make plastics like polyvinyl chloride (PVC) more flexible and are used in vinyl flooring, adhesives, detergents, lubricating oils and automotive plastics. People can be exposed by eating and drinking foods and beverages that have been in contact with plastic containers, according to the Centers for Disease Control and Prevention.

The human health effects of phthalate exposure are not known, according to the CDC, but they have been shown to affect the reproductive systems of lab animals.

“Phthalates are of concern because animal and epidemiology studies have linked exposure to a range of adverse health outcomes, from toxicity to developing male reproductive systems, neurodevelopmental issues, miscarriage, and preterm birth,” said Justin Colacino of the University of Michigan School of Public Health in Ann Arbor, who was not part of the new study.

Phthalates can mimic hormones in the body, and those in this study are also suspected to be carcinogens, Colacino told Reuters Health by email.

The study team used data from more than 8,000 participants in the National Health and Nutrition Examination Surveys between 2003 and 2010, including their self-reported fast food intake, the type of fast food they ate and the fat content of their food over the previous 24 hours. The surveys also included objective measurements of chemicals in urine samples.

As people’s fast food intake increased, so did evidence of phthalate exposure in their urine, according to the results in Environmental Health Perspectives.

There was no link between fast food consumption and urinary levels of bisphenol A (BPA), one of three plasticizing chemicals the researchers measured.

But people who got more than a third of their total calories from fast food over the previous day had 24 percent more of one chemical, di(2-ethylhexyl) phthalate (DEHP), and 39 percent more of a second one, diisononyl phthalate (DINP), than those who did not eat any fast food.

These chemical exposures seemed to be tied specifically to how much grain-based or grain- and meat-based fast food people ate.

The researchers accounted for age, sex, race, body weight, household income, and in some models adjusted for other potential sources of phthalate-containing foods, like those obtained from vending machines and restaurants, but the association with fast food remained, Zota said.

“These studies cannot alone establish causality,” she noted. But, “the results are both statistically significant and meaningful,” she said.

“Some likely sources include the tubing used upstream in the processing of dairy and meat, as well as the packaging at various stages of production,” she said. “Another potential source is the gloves employees wear while handling it,” which are often vinyl gloves, Zota said.

“The results suggest that if you as an individual want to limit your chemical exposures, one potential way to do that is limiting fast food and processed food,” she said.

But individuals can only do so much to limit their exposure to these ubiquitous chemicals, she said.

“It’s going to require a number of stakeholders to address the problems including people who regulate what can be added to food contact materials and food packaging, the Food and Drug Administration, fast food companies themselves, and manufacturers of tubing,” Zota said.

Phthalate levels are regulated in food in the European Union, but not in the U.S., she said.

SOURCE: 1.usa.gov/1YtM51A Environmental Health Perspectives, online April 13, 2016.