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Category: nutrition

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This research was done in a laboratory using cells, but the results support some other research finding that eating cruciferous vegetables frequently may help prevent cancer. They found that compound levels that were anti-cancer (killed off cancer cells) in this study could be achieved through diet alone. Cruciferous vegetables are vegetables of the family Brassicaceae (also called Cruciferae) such as cauliflower, cabbage, garden cress, bok choy, broccoli, brussels sprouts, kale, and similar green leaf vegetables. From Science Daily:

Plant-derived compound targets cancer stem cells

A compound and an enzyme that occur naturally in cruciferous vegetables--cauliflower, cabbage, broccoli and Brussels sprouts--may help prevent recurrence and spread of some cancers, according to researchers. When they treated human cervical cancer stem cells with phenethyl isothiocyanate (PEITC) in a Petri dish, about 75 percent died within 24 hours using a 20-micromolar concentration of the compound.

The precursor compound and enzyme in cruciferous vegetables combine during the chewing process to produce PEITC within the body, Dey explained. Though PEITC is a good candidate to develop as a dietary supplement, studies have also shown that sufficient cancer-preventing levels of PEITC can be achieved through diet alone.

When cancer is treated with chemotherapy or radiation, the tumor disappears but the cancer stem cells live on. "These cells are frequently resistant to conventional therapies," Dey said. Though cancer stem cells make up less than 5 percent of a tumor, they can regenerate the original tumor and migrate through the blood vessels spreading cancer to secondary locations."These tiny cells are very difficult to detect in a tumor," Dey pointed, adding that for a long time scientists did not even know they existed. 

Based on information from scientific literature, the concentrations of PEITC that Dey and her team typically use in their research -- 5 to 15 micromolars -- may be achieved through diets rich in certain types of cruciferous vegetables, particularly land cress and watercress.

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Published on 1 Comment on Obesity Markers Found In Urine

You can deceive yourself by calling yourself "big-boned" or "hefty", but your urine doesn't lie! Researchers found 29 biological markers in urine that are associated with body mass. These biological markers in urine are a "metabolic signature" of obesity. Note: Body mass index (BMI) is a measure of body fat based on height and weight that applies to adult men and women. From Medical Xpress:

Urine profiles provide clues to how obesity causes disease

Scientists have identified chemical markers in urine associated with body mass, providing insights into how obesity causes disease. Being overweight or obese is associated with higher risk of heart disease, stroke, diabetes and cancer, but the mechanisms connecting body fat and disease are not well understood.

The new study, led by Imperial College London, shows that obesity has a 'metabolic signature' detectable in urine samples, pointing to processes that could be targeted to mitigate its effects on health. 

Urine contains a variety of chemicals known as metabolites, from a vast range of biochemical processes in the body. Technologies that analyse the metabolic makeup of a sample can therefore offer huge amounts of information that reflects both a person's genetic makeup and lifestyle factors.

The Imperial researchers analysed urine samples from over 2,000 volunteers in the US and the UK. They found 29 different metabolic products whose levels correlated with the person's body mass index, and how they fit together in a complex network that links many different parts of the body.

Some of these metabolites are produced by bacteria that live in the gut, highlighting the potentially important role these organisms play in obesity. Altered patterns of energy-related metabolites produced in the muscles were also identified as being linked to obesity.

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Since so many people are taking Vitamin D supplements because of its supposed health benefits, the question becomes - how much is too much? For those desiring to take vitamin D supplements, what is a good maintenance dosage to take daily? That question has not been answered from the studies I've seen other than 1000 units per day is safe. However, sunlight is the best and safest source of vitamin D (even though that makes dermatologists nuts because of their concern with sunlight leading to skin cancer).From Science Daily:

Vitamin D toxicity rare in people who take supplements, researchers report

Over the last decade, numerous studies have shown that many Americans have low vitamin D levels and as a result, vitamin D supplement use has climbed in recent years. Vitamin D has been shown to boost bone health and it may play a role in preventing diabetes, cancer, cardiovascular disease and other illnesses. In light of the increased use of vitamin D supplements, Mayo Clinic researchers set out to learn more about the health of those with high vitamin D levels. They found that toxic levels are actually rare.

A vitamin D level greater than 50 nanograms per milliliter is considered high. Vitamin D levels are determined by a blood test called a serum 25-hydroxyvitamin D blood test. A normal level is 20-50 ng/mL, and deficiency is considered anything less than 20 ng/mL, according the Institute of Medicine (IOM).

The researchers analyzed data collected between 2002 and 2011 from patients in the Rochester Epidemiology Project...Of 20,308 measurements, 8 percent of the people who had their vitamin D measured had levels greater than 50 ng/mL, and less than 1 percent had levels over 100 ng/mL.

"We found that even in those with high levels of vitamin D over 50 ng/mL, there was not an increased risk of hypercalcemia, or elevated serum calcium, with increasing levels of vitamin D," says study co-author Thomas D. Thacher, M.D., a family medicine expert at Mayo Clinic. Hypercalcemia, or high blood calcium, can occur when there are very high levels of vitamin D in the blood. Too much calcium in the blood can cause weakness, lead to kidney stones, and interfere with the heart and brain, and even be life threatening.

The Mayo researchers also found that women over age 65 were at the highest risk of having vitamin D levels above 50 ng/mL. The result was not surprising because that's a group that often takes vitamin D supplements, Dr. Thacher says. Another notable outcome: The occurrence of high vitamin D levels over 50 ng/mL increased during the 10-year period of the study, from nine per 100,000 people at the start of the study up to 233 per 100,000 by the end.

Only one case over the 10-year study period was identified as true acute vitamin D toxicity; the person's vitamin D level was 364 ng/mL. The individual had been taking 50,000 international units (IU) of vitamin D supplements every day for more than three months, as well as calcium supplements. The IOM-recommended upper limit of vitamin D supplementation for people with low or deficient levels is 4,000 IU a day. 

Some natural sources of vitamin D include oily fish such as mackerel and salmon, fortified milk, and sunlight.

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A recent study confirms all my recent posts on the importance of fiber, fruits, vegetables, whole grains, seeds, nuts, and legumes for beneficial gut bacteria health (have to feed the them!). This study found dramatic changes in the colon (specifically in the colonic mucosa) from dietary changes in as little as 2 weeks.

In the study, for 2 weeks the Americans ate the typical low-fat, high fiber diet of South Africa which included foods such as hi-maize corn fritters, beans, salmon croquettes, spinach, red pepper and onions, homemade tater tots, mango slices,okra, tomatoes, corn muffins, black-eyed peas, catfish nuggets, navy bean soup, banana, lentils, rice, fish taco (tilapia), and pineapple. Meanwhile, people in South Africa ate an “American” high-fat, low-fiber diet. Foods included beef sausage links and pancakes for breakfast; hamburger and French fries for lunch; and meatloaf and rice for dinner. Plus all sorts of American favorites such as macaroni and cheese, steak, beef hot dog and beans.

The African style low fat and high fiber diet contained about 55 grams of fiber per day, and the American diet (low fiber and high fat ) had about 14 grams of fiber per day (which is typical of a Western diet). Bottom line: fiber feeds beneficial microbes in the gut, which results in beneficial changes in the gut (in the mucosa of the colon). From Science Daily:

Diet swap has dramatic effects on colon cancer risk for Americans and Africans

Scientists have found dramatic effects on risk factors for colon cancer when American and African volunteers swapped diets for just two weeks. Western diets, high in protein and fat but low in fibre, are thought to raise colon cancer risk compared with African diets high in fibre and low in fat and protein.The new study, published in Nature Communications today, confirms that a high fibre diet can substantially reduce risk, and shows that bacteria living in the gut play an important role in this effect.

Colon cancer is the fourth commonest cause of death from cancer worldwide, accounting for over 600,000 deaths per year. Colon cancer rates are much higher in the western world than in Africa or the Far East, yet in the United States, African Americans shoulder the greatest burden of the disease.

To investigate the possible roles of diet and gut bacteria, an international team including scientists from the University of Pittsburgh and Imperial College London carried out a study with a group of 20 African American volunteers and another group of 20 participants from rural South Africa. The two groups swapped diets under tightly controlled conditions for two weeks.... At the start, when the groups had been eating their normal diets, almost half of the American subjects had polyps -- abnormal growths in the bowel lining that may be harmless but can progress to cancer. None of the Africans had these abnormalities.

After two weeks on the African diet, the American group had significantly less inflammation in the colon and reduced biomarkers of cancer risk. In the African group, measurements indicating cancer risk dramatically increased after two weeks on the western diet.

"The findings suggest that people can substantially lower their risk of colon cancer by eating more fibre. This is not new in itself but what is really surprising is how quickly and dramatically the risk markers can switch in both groups following diet change. These findings also raise serious concerns that the progressive westernization of African communities may lead to the emergence of colon cancer as a major health issue."

Professor Stephen O'Keefe at the University of Pittsburgh, who directed the study, said: "Studies on Japanese migrants to Hawaii have shown that it takes one generation of westernization to change their low incidence of colon cancer to the high rates observed in native Hawaiians. Our study suggests that westernization of the diet induces changes in biomarkers of colon cancer risk in the colonic mucosa within two weeks. Perhaps even more importantly, a change in diet from a westernized composition to a 'traditional African' high fiber low fat diet reduced these biomarkers of cancer risk within two weeks, indicating that it is likely never too late to change your diet to change your risk of colon cancer."

The study found that a major reason for the changes in cancer risk was the way in which the bacteria in the gut -- known as the microbiome -- altered their metabolism to adapt to the new diet. In the American group, the researchers found that the African diet led to an increase in the production of butyrate, a byproduct of fibre metabolism that has important anti-cancer effects.

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There has been a lot of discussion in the last few years of our gut bacteria (hundreds of species), the microbiome (the community of microbes living within and on a person (gut, nasal cavities, mouth, sinuses, etc.), probiotics, the finding of a link between bacteria and some chronic diseases, and how the modern lifestyle and antibiotics are wiping out our beneficial gut microbes. I am frequently asked how one can improve or nurture the beneficial bacteria in our bodies.

While no one knows what exactly is the "best" or "healthiest" microbial composition of the gut, it does look like a diversity of bacteria is best (may make you healthier and more able to resist diseases). Research also suggests that the diversity and balance of bacteria living in the body can be changed and improved, and changes can occur very quickly. And that the microbial communities fluctuate for various reasons (illness, diet,etc.). Diet seems to be key to the health of your gut microbial community. Prebiotics feed the beneficial bacteria in the gut, probiotics are live beneficial bacteria, and synbiotics are a combination of prebiotics and probiotics. But don't despair - you can improve your gut microbial community starting now. The following are some practical tips, based on what scientific research currently knows.

SOME STEPS TO FEED AND NURTURE YOUR GUT MICROBES:

Eat a wide variety of foods, especially whole foods that are unprocessed or as minimally processed as possible. Eat everything in moderation.

Eat a lot of plant based foods: fruits, vegetables, whole grains, seeds, nuts, and legumes. Think of Michael Pollan's advice: "Eat food. Not too much. Mostly plants."

Eat more washed and raw fruits and vegetables (lots of bacteria and fiber to feed and nurture the bacteria). Some every day would be good.

Eat more soluble and insoluble types of fiber, and increase how many servings you eat every day. A variety of  fiber foods every day, and several servings at each meal, is best. Think fruits, vegetables, whole grains, legumes, nuts, seeds. (See How Much Dietary Fiber Should We Eat? - also has a chart with high fiber foods, and Recent Studies Show Benefits of Dietary Fiber)

Eat as many organic foods as possible. There is much we don't yet know, and pesticides are like antibiotics - they kill off microbes, both good and bad. Somehow I think that lowering the levels in your body of pesticides (as measured in blood and urine) can only be beneficial. Also, organic foods don't contain added antibiotics and hormones. (Eat Organic Foods to Lower Pesticide Exposures).  But even if you can't or won't eat organic foods, it is still better to eat non-organic fruits, vegetables, and whole grains than to not eat them.

Eat some fermented foods such as kimchi and sauerkraut (they contain live bacteria), kefir, and yogurts with live bacteria. Eat other bacteria containing foods such as cheeses, and again a variety is best (different cheeses have different bacteria).

Try to avoid or eat less of mass-produced highly processed foods, fast-foods, preservatives, colors and dyes, additives, partially hydrogenated oils, and high-fructose corn syrup. Read all ingredient lists on labels, and even try to avoid as much as possible "natural flavors" (these are chemicals concocted in a lab and unnecessary). Even emulsifiers (which are very hard to avoid) are linked to inflammation and effects on gut bacteria.

Avoid the use of triclosan or other "sanitizers" in soaps and personal care products (e.g., deodorants). Triclosan promotes antibiotic resistance and also kills off beneficial bacteria. Wash with ordinary soap and water.

Avoid unnecessary antibiotics (antibiotics kill off bacteria, including beneficial bacteria).

Vaginal births are best - microbes from the birth canal populate the baby as it is being born. If one has a cesarean section, then one can immediately take a swab of microbes from the mother's vagina (e.g., using sterile gauze cloth) and swab it over the newborn baby. (See post discussing this research by Maria Gloria Dominguez Bello )

Breastfeeding is best - breastfeeding provides lots of beneficial microbes and oligosaccharides that appear to enrich good bacteria in the baby’s gut.

Live on a farm, or try to have a pet or two. Having pets, especially in the first year of life,  ups exposure to bacteria to help develop and strengthen the immune system, and prevent allergies. Pets such as dogs and cat expose humans to lots of bacteria.

Get regular exercise or physical activity. Professional athletes have more diverse gut bacterial community (considered beneficial) than sedentary people.

Can consider taking probiotics - whether in foods or supplements. They are generally considered beneficial, but not well studied, so much is unknown. The supplements are unregulated, and the ones available in stores may not be those that are most commonly found in healthy individuals. Research the specific bacteria before taking any supplements. Researchers themselves tend to stay away from probiotic supplements and focus on eating a variety of all the foods mentioned above (fruits, vegetables, whole grains, seeds, nuts, legumes, fermented foods) to feed and nurture beneficial bacteria.

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The statements in this editorial may be obvious to many, but it is nicely written and needs to be said. Basically it says that exercise will not help you overcome the ill effects of a poor diet. I agree with what was said, but felt that what was missing was mention that a poor diet also has negative effects on the microbiome (the community of microbes living within the person) - which we know is linked to health problems.

From Medscape: Workouts Do Not Work Off Ill Effects of Poor Die

Exercise enthusiasts cannot work off the ill effects of an unhealthy diet, say the authors of an editorial published online April 22 in the British Journal of Sports Medicine. "Let us bust the myth of physical inactivity and obesity," the authors write. "You cannot outrun a bad diet."

Physical activity levels in Western nations have remained flat during the past 3 decades, even as obesity rates have exploded. That observation is just one sign that calories, not lack of exercise, are driving the obesity crisis, argue Aseem Malhotra, MD, honorary consultant cardiologist at Frimley Park Hospital, United Kingdom, and science director for Action on Sugar, United Kingdom, and colleagues.

"However, the obesity epidemic represents only the tip of a much larger iceberg of the adverse health consequences of poor diet," the authors write. They say that the Lancet global burden of disease reports concluded that poor diet contributes to more disease than a combination of inadequate physical activity, alcohol, and smoking. As many as 40% of people with normal body weight will suffer from metabolic abnormalities typically associated with obesity, the authors write, including hypertension, dyslipidemia, nonalcoholic fatty liver disease, and cardiovascular disease.

Dr Malhotra and colleagues blame food industry marketing for promoting exercise over diet, comparing food industry public relations with discredited tactics used by the tobacco industry in the past. They say Coca Cola "pushes the message that 'all calories count'; they associate their products with sport, suggesting it is ok to consume their drinks as long as you exercise. However science tells us this is misleading and wrong."

The kind of calorie matters too, they emphasize. Calories from sugar promote fat storage and hunger; fat calories induce satiety. For every 150 calories consumed from sugar, there is an 11-fold increase in the prevalence of type 2 diabetes independent of weight or physical activity levels compared with consumption of 150 calories of fat or protein.

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More good news for coffee drinkers! A number of studies have found that coffee drinking is protective against breast cancer (coffee inhibits the growth of tumors), but now research finds it is also protective against breast cancer recurring. The beneficial effects are seen with 2 or more cups of coffee per day. Other studies have found that lifestyle changes (such as weight loss, healthy eating, and exercise) are linked to lower rates of recurrence, but apparently coffee drinking can also be added to the list. This research found that not only is coffee drinking linked to smaller tumors in the first place, but it is also linked to lower rates of recurrence in women also taking tamoxifen. The researchers said: "In summary, this study shows inhibitory effects by caffeine and caffeic acid on breast cancer cell growth." Both caffeine and caffeic acid are present in coffee. From Science Daily:

Coffee protects against breast cancer recurrence, detailed findings confirm

A number of research studies have shown that coffee helps to protect against breast cancer. A new study led by Lund University, has confirmed that coffee inhibits the growth of tumors and reduces the risk of recurrence in women who have been diagnosed with breast cancer and treated with the drug tamoxifen.

The study, which is a follow-up of the results the researchers obtained two years ago, was carried out at Lund University and Skåne University Hospital, in collaboration with researchers in the UK. "Now, unlike in the previous study, we have combined information about the patients' lifestyle and clinical data from 1090 breast cancer patients with studies on breast cancer cells. The study shows that among the over 500 women treated with tamoxifen, those who had drunk at least two cups of coffee a day had only half the risk of recurrence of those who drank less coffee or none at all," explain researchers Ann Rosendahl and Helena Jernström, who obtained the results in collaboration with Jeff Holly and his research team at University of Bristol.

"The study also shows that those who drank at least two cups of coffee a day had smaller tumors and a lower proportion of hormone-dependent tumors. We saw that this was already the case at the time of diagnosis."

In the cell study, the researchers looked more closely at two substances that usually occur in the coffee drunk in Sweden -- caffeine and caffeic acid.

"The breast cancer cells reacted to these substances, especially caffeine, with reduced cell division and increased cell death, especially in combination with tamoxifen. This shows that these substances have an effect on the breast cancer cells and turn off signalling pathways that the cancer cells require to grow.

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More details are needed about this specific research, but this has been said before: foods are good, but supplements can be problematic. Here extra vitamins and minerals are linked to higher rates of cancer. From Science Daily:

Excessive use of dietary supplements linked to increase cancer risk

While dietary supplements may be advertised to promote health, a forum at the American Association for Cancer Research (AACR) Annual Meeting 2015 by University of Colorado Cancer Center investigator Tim Byers, MD, MPH, describes research showing that over-the-counter supplements may actually increase cancer risk if taken in excess of the recommended dietary amount.

"We are not sure why this is happening at the molecular level but evidence shows that people who take more dietary supplements than needed tend to have a higher risk of developing cancer," explains Byers, associate director for cancer prevention and control at the CU Cancer Center.

The line of research started 20 years ago with the observation that people who ate more fruits and vegetables tended to have less cancer. Researchers including Byers wanted to see if taking extra vitamins and minerals would reduce cancer risk even further. "When we first tested dietary supplements in animal models we found that the results were promising," says Byers. "Eventually we were able to move on to the human populations. We studied thousands of patients for ten years who were taking dietary supplements and placebos."

The results were not what they expected."We found that the supplements were actually not beneficial for their health. In fact, some people actually got more cancer while on the vitamins," explains Byers. One trial exploring the effects of beta-keratin supplements showed that taking more than the recommended dosage increased the risk for developing both lung cancer and heart disease by 20 percent. Folic acid, which was thought to help reduce the number of polyps in a colon, actually increased the number in another trial.

"This is not to say that people need to be afraid of taking vitamins and minerals," says Byers. "If taken at the correct dosage, multivitamins can be good for you. But there is no substitute for good, nutritional food." Byers says that people can get the daily recommended doses of vitamins and minerals in their diets by eating healthy meals and that many adults who take vitamin supplements may not need them."

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The Center for Public Integrity, a nonpartisan, nonprofit investigative news organization has just published a number of articles about how companies have added thousands of ingredients to foods with little or no government oversight. This loophole is a decades old law that allows an additive to be "generally recognized as safe" or GRAS without the FDA getting involved. This is why there are some additives in American foods that are NOT allowed in Europe or other countries. And that is why I always read the ingredient lists of foods. I even hate to buy foods that have the nice sounding "natural ingredients" in the ingredient list. What are these so-called natural ingredients that have been concocted in some lab and added to our foods? Does anyone know?  Some earlier posts on this issue: August 19, 2014 and June 16, 2014 . The following are excerpts from the April 14, 2015 story from NPR:

Why The FDA Has Never Looked At Some Of The Additives In Our Food

Companies have added thousands of ingredients to foods with little to no government oversight. That's thanks to a loophole in a decades-old law that allows them to deem an additive to be "generally recognized as safe" — or GRAS — without the U.S. Food and Drug Administration's blessing, or even its knowledge.

The loophole was originally intended to allow manufacturers of common ingredients like vinegar and table salt — when added to processed foods — to bypass the FDA's lengthy safety-review process. But over time, companies have found that it's far more efficient to take advantage of the exemption to get their products on shelves quickly. Some of these products contain additives that the FDA has found to pose dangers. And even ingredients the agency has agreed are GRAS are now drawing scrutiny from scientists and consumer groups that dispute their safety.

Critics of the system say the biggest concern, however, is that companies regularly introduce new additives without ever informing the FDA. That means people are consuming foods with added flavors, preservatives and other ingredients that are not reviewed at all by regulators for immediate dangers or long-term health effects. The vast majority of food additives are safe. Some, however, have proved to cause severe allergic reactions or other long-term health effects. Scientists and advocates worry about the growing number of ingredients that the FDA doesn't know about and is not tracking.

Rather than going through the painstaking FDA-led review process to ensure that their new ingredients are safe, food companies can determine on their own that substances are "generally recognized as safe." They can then ask the FDA to review their evaluation — if they wish. Or they can take their ingredients straight to market, without ever informing the agency."FDA doesn't know what it doesn't know," said Steve Morris of the Government Accountability Office, which published a report in 2010 that found that "FDA's oversight process does not help ensure the safety of all new GRAS determinations."

For a company to determine that an ingredient is "generally recognized as safe," it must establish that the additive's safety is commonly understood by qualified scientific experts. But some ingredients defy consensus, as consumers, scientific groups and sometimes even the FDA have pointed out. Even GRAS additives that have been used in food for decades are now coming under fire as their uses expand and scientific research emerges that casts doubt on their safety. This is true of one of the most known — and vilified — GRAS additives: partially hydrogenated oil, a form of trans fat. Widely used in food products including fried foods and cake mixes, trans fats have been named by public health experts as a contributor to heart disease, stroke and Type 2 diabetes. Despite strong pushback from industry, the FDA in November 2013 made a tentative determination that artificial trans fats should not have GRAS status, and the agency is likely to make that determination final this summer.

But it's the ingredients the public doesn't know about that have critics of the GRAS system most worried. Researchers for the Pew Charitable Trusts and the Natural Resources Defense Council say that allowing companies to make safety determinations without telling the FDA makes it nearly impossible to identify whether there are health effects caused by long-term exposure to certain ingredients.

Their concerns are heightened because safety decisions often rest in the hands of a small group of scientific experts selected by companies or consulting firms with a financial incentive to get new ingredients on the market. Several of these scientists, a Center for Public Integrity investigation found, previously served as scientific consultants for tobacco companies during the 1980s and 1990s, when the tobacco industry fought vigorously to defend its products.

The GRAS loophole was born in 1958. Americans were growing concerned about the increased use of preservatives and other additives in food, so Congress passed — and President Dwight Eisenhower signed — the first law regulating ingredients added to food.

To restore confidence, the law set up a system requiring companies to submit new ingredients to an extensive FDA safety review before going to market..."There are plenty of ingredients that are receiving GRAS status the safety of which are in dispute." In the past five decades, the number of food additives has skyrocketed — from about 800 to more than 10,000. They are added to everything from baked goods and breakfast cereals to energy bars and carbonated drinks.

For the full investigation, head to the Center for Public Integrity's site. 

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The science world has recently been abuzz with the results finding that an isolated American Indian group (the Yanomami) in the Venezuelan  Amazon have the most diverse microbiome (microbial community) ever discovered in humans.About double those found in humans living in the U.S. The scientists suggest that our Western lifestyle with processed foods, antibiotic use, sanitation, use of antibacterials, Cesarean sections, bottle-feeding (instead of breastfeeding) all have reduced microbial diversity in humans living in developed countries such as the United States. It is currently thought that reduced diversity is linked to some chronic diseases and even some cancers.From Nature:

Bacteria bonanza found in remote Amazon village

An isolated American Indian group in the Venezuelan Amazon hosts the most-diverse constellation of microbes ever discovered in humans, researchers reported on 17 April in Science Advances1.Surprisingly, the group's microbiome includes bacteria with genes that confer antibiotic resistance — even though its members, part of the Yanomami tribe, are not thought to have been exposed to the drugs.

But scientists still do not understand all the factors that determine the make-up of a person's microbiome. “We do know that food, environment and chemicals play the big roles,” says Sarkis Mazmanian, a microbiologist at the California Institute of Technology in Pasadena. The wide adoption of antibiotics, rigorous hygiene and processed diets is thought to have have cut down the genetic diversity of microbiomes in the developed world.

This makes the microbiomes of individual Yanomami particularly interesting, Dominguez-Bello says. The researchers took oral, faecal and skin samples from 34 people in a small Yanomami community that was unknown to the Western world until 2008, when it was spotted by helicopter....When researchers analysed the microbial DNA in those samples, they found that the average Yanomami's microbiota had twice as many genes as that of the average US person. More surprisingly, the Yanomami microbiome was even more diverse than those reported for other indigenous groups in South America and in Africa.

From New Scientist: Is super-diverse Amazon microbiome something to strive for?

The Yanomami people in the Venezuelan rainforest have the most diverse population of gut microbes ever seen, far more varied than Western guts. Does it matter?

Hunter-gathering in the rainforests and mountains of northern Brazil and southern Venezuela, the Yanomami eat a high-fibre diet based largely on cassava. For thousands of years, some groups have lived without contact with the rest of the world and are thought to be some of the few remaining communities never to have been exposed to antibiotics, which can wipe out the microbes in your gut.Sequencing the genes in the faecal samples revealed that the Yanomami carried nearly double the diversity of microbial species in their intestines compared with people living in the US. They also had about 30 to 40 per cent more diversity than a less isolated group of Venezuelan hunter-gatherers that has largely maintained its traditional lifestyle but has occasionally used antibiotics and eaten processed foods.

"Our results suggest that Westernisation leads to the reduction of diversity, to different microbiota compositions," Maria Dominguez-Bello of the New York University School of Medicine, who led the research, told a teleconference on Wednesday. Her colleague Jose Clemente of the Icahn School of Medicine at Mount Sinai in New York, said the results suggest that even minimal exposure to modern lifestyle practices such as using antibacterial soaps and cleansers, taking antibiotics and having Caesarean sections, which mean babies don't pass through their mother's birth canal and pick up her microbes, can result in a dramatic loss of microbial biodiversity.

So does a more diverse microbiome make for a healthier person? Possibly. Healthier people do seem to host a more diverse array of microbes but it's hard to know whether one causes the other. There is some evidence that losing certain microbial species is linked to some cancers, plus giving mice antibiotics can make them gain weight, so perhaps a good mix of microbes in your gut can keep you from piling on the pounds.

Walter doesn't recommend striving drastically to make the paltry Western gut look more Yanomamian. Poor sanitation is probably one factor contributing to the Papua New Guinean's high microbial diversity, but they have high levels of infectious diarrhoea as a result – not a situation that Western urbanised nations would want to return to.