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Author: Sima

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For many years it was thought that yo-yo dieting resulted in higher cancer risk. So the findings of this study are a relief. Researchers looked at weight cycling (yo-yo dieting) and incidence for all cancer and 15 individual cancers among more than 132,000 participants during 17 years of study and found NO association with overall risk of cancer or any individual cancer. So feel free to diet and lose weight for the health benefits. From Science Daily:

Yo-yo dieting not associated with increased cancer risk

The first comprehensive study of its kind finds weight cycling, repeated cycles of intentional weight loss followed by regain, was not associated with overall risk of cancer in men or women. The study by American Cancer Society investigators is the largest to date to investigate weight cycling with cancer risk....Weight cycling was also not associated with any individual cancer investigated. The authors of the study say people trying to lose weight should be encouraged to do so even though they may regain it.

With almost half of American adults reporting they are trying to lose weight, and with most weight loss not maintained, weight cycling is very common. Previous studies in animals and humans had suggested that weight cycling may affect biological processes that could lead to cancer, such as increased T-cell accumulation, enhanced inflammatory responses in adipose tissue, and lowered natural killer cell cytotoxicity. However, many of these findings have not been replicated, and at least two previous studies showed no associations between weight cycling and cancer.

For the latest study, researchers led by Victoria Stevens, PhD, American Cancer Society Strategic Director, Laboratory Services, examined weight cycling and cancer among more than 132,000 men and women enrolled in the Cancer Prevention Study II Nutrition Cohort. Begun in 1992/1993, the Nutrition Cohort gathered detailed dietary information from men and women ages 50 to 74 participating in the Society's larger Cancer Prevention Study II, to explore nutrition's effect on and cancer incidence and mortality. Investigators looked at weight cycling and incidence for all cancer and 15 individual cancers. More than 25,000 participants developed cancer during 17 years of study.

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Research found that more time spent standing rather than sitting is associated with improved blood sugar, fats in the blood and cholesterol levels, and replacing time spent sitting with time walking is associated with a smaller waistline and body mass index (BMI). The researchers' motto: Stand Up, Sit Less, Move More.

Activity adds up over the course of a day as Dr.Lopez-Jimenez of the Mayo Clinic points out: "A person walking while at work for two hours, standing for another four hours, and performing some daily chores at home for another hour will burn more calories than jogging or running for 60 minutes. From Medical Xpress:

Get up for your heart health and move for your waistline

More time spent standing rather than sitting could improve your blood sugar, fats in the blood and cholesterol levels, according to a new study published today (Friday) in the European Heart Journal. The study also shows that replacing time spent sitting with time walking could have additional benefits for your waistline and body mass index (BMI).

Researchers in Australia gave activity monitors to 782 men and women, aged 36-80 years, who were taking part in the Australian Diabetes, Obesity and Lifestyle Study. The monitors were capable of determining, very accurately, how long each participant spent sleeping, sitting or lying down, standing and stepping (which includes walking and running)....participants each wore an activity monitor on their thigh for 24 hours a day over a seven-day period. .

An extra two hours per day spent standing rather than sitting was associated with approximately 2% lower average fasting blood sugar levels and 11% lower average triglycerides (fats in the blood). Extra standing time was also associated with 0.06 mmol/L higher average levels of the "good" type of cholesterol, HDL, and a 6% lower average total/HDL cholesterol ratio, which indicates an improvement in the total amount of HDL cholesterol in relation to "bad" LDL cholesterol.

Replacing two hours a day of sitting time with stepping was associated with an approximately 11% lower average BMI and a 7.5cm smaller average waist circumference. In addition, average blood sugar levels fell by approximately 11% and average triglycerides by 14% for every two hours spent walking rather than sitting, while HDL cholesterol was 0.10 mmol/L higher. There was no significant effect on BMI or waistline of replacing sitting time with standing.

"However, it is important to say that not all sitting is bad; but if people can incorporate alternatives to sitting wherever possible, it may benefit their heart and metabolic health. Our message is to 'Stand Up, Sit Less, Move More'."She said the study had also produced evidence of how common standing is during the waking day. "Standing takes up nearly a third of waking hours, and among this group of participants who could choose when they sat, stood or walked, the standing had health benefits.

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One study points out the difficulty of weight loss in overweight adults, because so few actually are able to get down to a normal weight or even lose a mere 5% of body weight (for example. 10 pounds for a 200 pound person or 15 pounds for a 300 pound person). The annual chance of an obese person attaining normal body weight is only 1 in 210 for men and 1 in 124 for women,and the annual chance of obese patients achieving five per cent weight loss was 1 in 12 for men and 1 in 10 for women.  The second study highlights how well weight loss treats "fatty liver" (which is a problem in middle-aged overweight people). Fatty liver or nonalcoholic steatohepatitis (NASH), which affects 2 to 5 percent of Americans, can be severe and can lead to cirrhosis, in which the liver is permanently damaged and scarred and no longer able to work properly.

After reading scientific studies nonstop for the last few years, it seems that the best, easiest way to lose weight is to have lifestyle changes rather than focusing just on a "weight-loss diet": increase activity levels (yes, walking counts) and switch to a more plant based diet or Mediterranean diet (lots of fruits, vegetables, whole grains, legumes, seeds, nuts, olive oil, some fish each week) and decrease the amount of typical Western style diet (highly processed foods. lots of meat and coldcuts, lots of fat, fast foods, soda). Try to only eat within 12 hours each day (for example, 8am to 8pm) and don't eat the other 12 hours. And of course eat fewer calories (it should be easier  to do if you substitute fruits and vegetables for high calorie processed foods such as ice cream, french fries, and sweets). And yes, of course it's really hard to lose weight, but the health benefits of weight loss are enormous. From Medical Xpress:

Low chance of recovering normal body weight highlights need for obesity prevention

The chance of an obese person attaining normal body weight is 1 in 210 for men and 1 in 124 for women, increasing to 1 in 1,290 for men and 1 in 677 for women with severe obesity, according to a study of UK health records led by King's College London. The findings, published in the American Journal of Public Health, suggest that current weight management programmes focused on dieting and exercise are not effective in tackling obesity at population level.The research, funded by the National Institute for Health Research (NIHR), tracked the weight of 278,982 participants (129,194 men and 149,788) women using electronic health records from 2004 to 2014.

The annual chance of obese patients achieving five per cent weight loss was 1 in 12 for men and 1 in 10 for women. For those people who achieved five per cent weight loss, 53 per cent regained this weight within two years and 78 percent had regained the weight within five years.

Overall, only 1,283 men and 2,245 women with a BMI of 30-35 reached their normal body weight, equivalent to an annual probability of 1 in 210 for men and 1 in 124 for women; for those with a BMI above 40, the odds increased to 1 in 1,290 for men and 1 in 677 for women with severe obesity. Weight cycling, with both increases and decreases in body weight, was also observed in more than a third of patients. The study concludes that current obesity treatments are failing to achieve sustained weight loss for the majority of obese patients.

Dr Alison Fildes, first author from the Division of Health and Social Care Research at King's College London (and now based at UCL), said: 'Losing 5 to 10 per cent of your body weight has been shown to have meaningful health benefits and is often recommended as a weight loss target..... More importantly, priority needs to be placed on preventing weight gain in the first place.'

From Medical Xpress:  Weight loss for a healthy liver

Weight loss through both lifestyle modification and bariatric surgery can significantly reduce features of nonalcoholic steatohepatitis (NASH), a disease characterized by fat in the liver, according to two new studies published in Gastroenterology..."we most commonly see this condition in patients who are middle-aged and overweight or obese," said Giulio Marchesini, MD, from University of Bologna, Italy, and lead author of an editorial summarizing these two studies. "These two large prospective cohort studies strengthen the evidence that, no matter how you lose weight, weight loss improves liver health. Both bariatric surgery for morbidly obese patients or lifestyle modifications are viable options."

Lifestyle modifications: Eduardo Vilar-Gomez and colleagues from Cuba report in Gastroenterology that a weight reduction of 10 percent or more, induced by a comprehensive lifestyle program, is necessary to bring about NASH resolution and reverse scarring of the liver in overweight and obese patients. To a lesser degree, modest weight loss (7 to 10 percent) reduced disease severity in certain subsets of patients, including male patients and those without diabetes. Conversely, 93 percent of the patients with little or no weight reduction (less than 5 percent) experienced worsening of liver scarring....While promising, less than 50 percent of patients achieved the necessary weight loss goal of 7 to 10 percent, providing a stark reminder of the sustainability of weight loss interventions.

Bariatric surgery: For appropriate morbidly obese patients with NASH who have previously failed to lose weight through lifestyle modifications, bariatric surgery may be considered. In the second Gastroenterology study, Guillaume Lassailly and colleagues from France report that, one year after bariatric surgery, NASH had disappeared from 85 percent of patients and reduced the pathologic features of the disease after 1 year of follow-up. NASH disappeared from a higher proportion of patients with mild NASH before surgery (94 percent) than severe NASH (70 percent). More studies are needed to determine the long-term effects of bariatric surgeryin morbidly or severely obese patients with NASH.

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Several recent studies have found that constant exposure to high levels of air pollution has negative effects on the brain. The last post described negative effects on the gray matter in brains (resulting in smaller brain volumes) of elderly women from air pollution, but this study found negative effects (lower grade point averages) in young children from high air pollution. From Environmental Health News:

Bad air means lower grade point averages in Texas

Fourth and fifth graders in El Paso, Texas, are more likely to have lower grade point averages if heavily exposed to contaminated air at home, according to a new study.It bolsters a growing body of evidence that air pollution can impair success in school.

They found that for all types of air pollution sources, more exposure corresponded with lower grade point averages. Only one type of pollution—point sources such as factories—was not significantly linked to lower grade point averages.University of Texas at El Paso researchers analyzed the grade point averages of 1,895 children and, using their home location, estimated their exposure to air toxics—such as benzene, arsenic, lead, mercury, hydrochloric acid, toluene, vinyl bromide, xylenes, and diesel particulate matter—using federal data.

“Effects appear to be insidious, since they are mild, unlikely to be perceived, and, hence, unlikely to be addressed in any way … seemingly trivial effects on children’s development may translate into substantial impacts throughout the life course in terms of physical and mental health and personal success,” the authors wrote.The researchers did control for some other things that can affect children’s grades such as poverty, mother’s age, education and ability to speak English, and the child’s race and sex.

Still, the study doesn’t prove that dirty air makes kids do worse in school. It does, however, suggest children’s developing bodies are more susceptible to air pollution, which can harm their respiratory systems and brain.Air pollution might hamper kids’ grades via two primary ways: Illnesses, mostly respiratory, that would make them miss school, and developmental problems resulting from long-term exposure, said Sara Grineski, an associate professor of sociology at The University of Texas at El Paso and co-author of the new study.

Others have found similar links between air pollution and academic performance. Three months ago Columbia University's Perera and colleagues reported that New York City children born to mothers in poverty and exposed to certain air toxics during pregnancy had lower IQs.  Perera, tracking the mothers and children since before birth, said the pollution exposure prior to birth is more strongly linked to learning and behavioral problems. 

In the current study it’s unclear if the children were exposed in their mothers’ womb—an exposure window that is critical to brain development, Perera said....Other studies support this—in February Calderón-Garcidueñas and colleagues reported Mexico City smog was linked to impaired short-term memory and IQ in children.

The city is more than 80 percent Hispanic....Previous studies have shown that El Paso’s minorities are disproportionately impacted by toxics, Grineski said. The city of 675,000 is one of the worst when it comes to particulate matter—a mix of substances emitted by combustion sources, including cars, trucks, industrial plants and wood burning—especially coarse particulates, PM10, those between 2.5 and 10 micrometers (from about 25 to 100 times thinner than a human hair, according to the EPA). El Paso’s 24-hour PM10 average is about 233 micrograms per cubic meter of air, according to the latest EPA data from 2013, which was eighth highest among more than 500 U.S. cities. El Paso, along with Laredo, has the highest carbon monoxide levels in Texas.

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Several recent studies found that air pollution has a negative effect on the brain. This study of elderly women in North Carolina found that long-term exposure to higher levels of air pollution (specifically fine particulate matter smaller than 2.5 micrometers (called PM2.5) resulted in smaller brain volumes (especially the brain's white matter). They studied elderly women (aged 71 to 89), but the findings should be of concern to everyone exposed to high levels of air pollution.  White matter connects brain regions (with nerve fibers that pass signals throughout the brain) and determines how information is processed in the brain. The researchers pointed out that other recent studies reported that high air pollution is linked to cognitive decline and accelerated brain aging. From Futurity:

AIR POLLUTION MAY SHRINK BRAIN’S WHITE MATTER

Exposure to air pollution may have a negative impact on how the brain’s white matter ages. Older women who lived in geographic locations with higher levels of fine particulate matter in ambient air had significantly smaller white matter volumes across a wide range of brain areas, new research shows.

Fine particulate matter is smaller than 2.5 micrometers and is known as PM2.5, a form of pollution that easily enters the lungs and possibly the bloodstream. White matter connects brain regions and determines how information is processed in the brain....“Our study provides convincing evidence that several parts of the aging brain, especially the white matter, are an important target of neurotoxic effects induced by long-term exposure to fine particles in the air.”

The study found that older women ages 71 to 89 who had lived in places with greater PM2.5 exposures had significantly smaller volumes of white matter and that this could not be explained by the geographic region where they lived, their race or ethnic background, socioeconomic status, lifestyle, or medical conditions that may also influence brain volumes.

The researchers performed brain magnetic resonance imaging scans of 1,403 women who are part of the Women’s Health Initiative Memory Study (WHIMS), a nationwide report based at Wake Forest Baptist Medical Center in Winston-Salem, NC. The researchers also used residential histories and air monitoring data to estimate the participants’ exposure to air pollution in the previous six to seven years.

White matter contains nerve fibers and connects brain regions with each other by traveling deep within and passing nerve signals throughout the brain. Gray matter is primarily composed of neuronal cell bodies, dendrites, glial cells, and capillaries. The study did not find impacts from exposure to air pollution in participants’ gray matter.

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People fear dementia and Alzheimer's disease, because they are progressive diseases that nothing treats successfully. However, in the past year there have been some studies showing improvements with lifestyle changes (not cures, but for some the progression was slowed or showing some improvements).

The latest studies found that exercise (especially aerobic execise) had some beneficial effects on those with mild cognitive impairment (MCI), Alzheimer's disease, and vascular cognitive  impairment (VCI): neuropsychiatric improvements, improvements in biomarkers for the disease, and improved blood flow to the brain. From Medscape:

Physical Activity May Help Treat Dementia

New research shows that being physically active not only reduces cognitive decline and improves neuropsychiatric symptoms in patients with dementia but may actually reduce Alzheimer's disease (AD) biomarkers, including amyloid and tau protein in the brain. Exercise could also benefit patients with types of dementia other than AD, another study suggests.Some of this promising new research on exercise was presented at the Alzheimer's Association International Conference (AAIC) 2015. 

Danish researchers had already presented cognition-related results of the multicenter ADEX study ...The intervention consisted of 1 hour of aerobic exercise three times a week for 16 weeks. The control group received usual care..... The analysis found that these [neuropsychiatric] symptoms improved in the 66 patients in the "high exercise"group... The NI is a 12-item questionnaire that rates, among other things, depression, apathy, agitation, hallucinations, irritability, weight loss, and sleep."We saw that the control group got worse; there was a small decline in this group, which you would expect because this is progressive disease," said Steen Hasselbalch, MD, Danish Dementia Research Centre, Copenhagen, Denmark. "But the intervention group remained at the same level and even got a little better, so at end of the intervention there was a significant difference."

The question arises of whether exercise could not just delay worsening of symptoms but actually change brain pathology.The answer, suggests other research, is yes. In a separate study presented at the AAIC 2015, researchers found decreased phosphorylated tau (P tau) in older, previously sedentary persons completing a 6-month regimen of moderate- to high-intensity aerobic exercise.

The study enrolled 70 patients aged 55 to 89 years with prediabetes as well as amnestic mild cognitive impairment (MCI)....We think they are at high, high risk for developing dementia of the Alzheimer's type." These patients were randomly assigned to the aerobic exercise group or to the stretching group. Those in the aerobic group started slowly — 10 minutes of exercise a week — and gradually built the time and intensity up over 6 weeks to the point where they were exercising 45 minutes a day, 4 days a week, at 75% to 85% of their maximum heart rate...."This group had a choice of exercises: treadmill, stationary cycling, elliptical trainer, or preapproved group classes.

The stretching group, whose members could do balance exercises, gentle yoga, and other approved classes in addition to stretching, maintained a maximum heart rate of below 35%. All exercises were adapted to the needs and limitations of individual patients and were done at a local YMCA.

The researchers looked at biomarkers in cerebrospinal fluid (CSF), including P tau protein and amyloid β 42....Most intervention trials don't show such changes in P tau. "But we saw it with exercise and no medications," said Dr. Baker. "Exercise was enough to move a biomarker that indicates the severity of the disease."  It wasn't surprising, she added, that this was true only for older patients. "It may be that before age 70, you have a lot of compensatory mechanisms that help to maintain brain health, and after 70, those start breaking down."

The study also showed that the aerobic activity increased blood flow to the brain...The researchers demonstrated that the increased blood flow was in regions characteristically affected by aging and AD (ie, memory and processing). Cognitive benefits were particularly noteworthy for executive function..."Our brain imaging results are just fantastic; they show some really nice increases in blood flow in the areas of brain that support executive function and areas of the brain that normally show decreased flow for people with MCI, so it's reversing the blood flow detriment in MCI."

AD may not be the only dementia potentially treatable through exercise. Another study discussed at the meeting showed that this intervention may help those with vascular cognitive impairment (VCI). It's the first intervention trial to suggest that exercise can improve cognition in patients with confirmed VCI, said Teresa Liu- Ambrose, PhD, Canada Research Chair, University of British Columbia, Vancouver, Canada, who reported the results.The 6-month study included 71 patients aged 56 to 96 years with mild VCI of varying physical capacities. They were assigned to usual care that included a nutrition component or to an intervention of moderate-intensity walking, 3 times a week for an hour....In a subset of patients who had neuroimaging, there was "evidence of efficiency" in the brain of those who exercised, Dr Liu-Ambrose told Medscape Medical News.

Published on Leave a comment on What’s In the “Natural” Flavors In Our Foods?

I've been reading and thinking about "natural flavors" ever since my earlier posts about food additives (April 20, 2015, August 19, 2014). What exactly are natural flavors and how are they different from artificial flavors?  And why are they even found in organic foods? The more I read, the more I want to avoid them , but it seems to be really, really hard to do so because they seem to be everywhere, even in what we think of as basic foods (e.g., butter). Bottom line: both are chemicals concocted in labs and manufactured in factories. Read labels and try to eat as many unprocessed foods as possible to avoid them.We know very little about many of them, and if they have health effects. Note that the term "natural flavors" may include many chemicals in the "flavor mixtures" (incidental additives) that don't have to be listed on the labels. Currently there are more than 2700 natural flavors being used in the USA. The following are excerpts from articles and a book published in 2015.

From CNN:   What are natural flavors, really?

Look at the food label of almost any packaged good you consume and odds are you'll spot the term "natural flavors." But have you ever wondered what this mysterious additive actually contains? The answer isn't as clear as you might think.Though natural flavors may sound better than their presumably chemical-laden alternative — artificial flavors — it turns out they are not actually all that different.

In the Environmental Working Group's Food Scores database of over 80,000 foods, "natural flavor" is the fourth most common ingredient listed on labels. The only ingredients that outrank it: salt, water and sugar. Yet, natural flavoring isn't nearly as simple as these three pantry staples."Natural and artificial flavors play an interesting role in food. They're essentially providing the taste and often they're added to make the food more appealing, or to potentially replace something that's lost through processing, storage or in some cases even from pasteurizing," says David Andrews, senior scientist at the Environmental Working Group. One place you'll often spot natural or artificial flavor is in orange juice; manufacturers will add faux flavor to juice after it's packaged in the plant, to ensure uniformity.

"The differentiation is really down to the origin of those molecules, whether synthetically processed in a lab or purified in a lab but from a natural source," Andrews says. Here's where it gets even muddier: Added flavoring, both natural and artificial, could contain anywhere from 50 to 100 ingredients. And all of the extra ingredients in flavors often aren't as innocent as you'd hope they would be."The mixture will often have some solvent and preservatives — and that makes up 80 to 90 percent of the volume [of the flavoring]. In the end product, it's a small amount, but it still has artificial ingredients," Andrews says.  ...continue reading "What’s In the “Natural” Flavors In Our Foods?"

Published on Leave a comment on A Mix of Bacteria Protect Against Infections?

More research that supports that both more variety (diversity) of microbes and the actual mix of types of microbes are involved in a healthy gut microbiome. Healthy communities don't have just one important species of bacteria, but a mix of bacteria, and some mixes of bacteria work better than others in preventing infections. One can say that some mixes of bacteria are "protective" against infections. And once again, antibiotics screw up the microbial communities and cause imbalances. This study was done in mice looking at gut bacteria and Clostridium difficile (which kills about 14,000 Americans annually), but they are now continuing this research in humans. From Medical Xpress:

It takes a village... to ward off dangerous infections? New microbiome research suggests so

Like a collection of ragtag villagers fighting off an invading army, the mix of bacteria that live in our guts may band together to keep dangerous infections from taking hold, new research suggests. But some "villages" may succeed better than others at holding off the invasion, because of key differences in the kinds of bacteria that make up their feisty population, the team from the University of Michigan Medical School reports. The researchers even show it may be possible to predict which collections of gut bacteria will resist invasion the best—opening the door to new ways of aiding them in their fight.

Working in mice, the team studied one of the most dangerous gut infections around: Clostridium difficile, which kills more than 14,000 Americans a year. C-diff also sickens hundreds of thousands more, mostly hospital patients whose natural collection of gut bacteria—their gut microbiome—has been disturbed by antibiotics prescribed to protect them from other infections.

In a new paper published in the journal mBIO, the team reports the results from tests of seven groups of mice that were given different antibiotics, then were exposed to C-diff spores. The scientists used advanced genetic analysis to determine which bacteria survived the antibiotic challenge, and looked at what factors made it most likely that C-diff would succeed in its invasion.The team also developed a computer model that accurately predicted C-diff's success rate for other mice in the study, based solely on knowing what bacteria the mice had in their natural gut 'village'. The model succeeded 90 percent of the time.

"We know that individual humans all have different collections of gut bacteria, that your internal 'village' is different from mine. But research has mostly focused on studying one collection at a time," says Patrick D. Schloss, Ph.D., the U-M associate professor of microbiology and immunology who led the team. "By looking at many types of microbiomes at once, we were able to tease out a subset of bacterial communities that appear to resist C-diff colonization, and predict to what extent they could prevent an infection."

Schloss, who is a key member of the Medical School's Host Microbiome Initiative, notes that no one species of bacteria by itself protected against colonization. It was the mix that did it. And no one particular mix of specific bacteria was spectacularly better than others - several of the diverse "villages" resisted invasion.

Resistance was associated with members of the Porphyromonadaceae, Lachnospiraceae, Lactobacillus, Alistipes, and Turicibacter families of bacteria. Susceptibility to C. difficile, on the other hand, was associated with loss of these protective species and a rise in Escherichia or Streptococcus bacteria. "It's the community that matters, and antibiotics screw it up," Schloss explains. Being able to use advance genetic tools to detect the DNA of dozens of different bacteria species, and tell how common or rare each one is in a particular gut, made this research possible.

A Clostridium difficile cell.                                                     Credit: Centers for Disease Control and Prevention

Published on Leave a comment on Why Breastfeeding Is So Important

There has been much discussion recently about breastfeeding - why is it so important? Is it really better than formula? The answer is: YES, breastfeeding is the BEST food for the baby, and for a number of reasons. Not only is it nature's perfect food for the baby, but it also helps the development of the baby's microbiome or microbiota (the community of microbes that live within and on humans).

Specifically, breast milk transmits about 700 species of bacteria to the baby - bacteria that are important in developing the baby's microbiota, bacteria that are important for the baby's development and health in many ways (including the immune system). No formula does that. Not even close.

There is obviously much we don't know or understand yet, but finding 700 species in breast milk is a big deal. The most variety was in colostrum (the first milk), but even after 6 months (mature milk) they found hundreds of species of bacteria. What was also interesting was that the bacteria species in the breast milk varied whether the baby was born by vaginal birth, unplanned cesarean, or planned cesarean (this last had a somewhat different bacterial community which persisted through the 6 months of the study).

By the way, in the original study, the authors made a point of saying that the 700 bacteria species are NOT bacterial contaminants, but meant to be there! (for those who want to sterilize and pasteurize everything because they think that all bacteria are bad).

This study is from 2013, but well worth reading. From Science Daily: Breast milk contains more than 700 species of bacteria, Spanish researchers find

Researchers have traced the bacterial microbiota map in breast milk and identified the species of microbes taken from breast milk by infants. The study has revealed a larger microbial diversity than originally thought: more than 700 species. The breast milk received from the mother is one of the factors determining how the bacterial flora will develop in the newborn baby.

A group of Spanish scientists have now used a technique based on massive DNA sequencing to identify the set of bacteria contained within breast milk called microbiome.  Colostrum is the first secretion of the mammary glands after giving birth. In some of the samples taken of this liquid, more than 700 species of these microorganisms were found, which is more than originally expected by experts.

"This is one of the first studies to document such diversity using the pyrosequencing technique (a large scale DNA sequencing determination technique) on colostrum samples on the one hand, and breast milk on the other, the latter being collected after one and six months of breastfeeding," explain the coauthors, María Carmen Collado, researcher at the Institute of Agrochemistry and Food Technology (IATA-CSIC) and Alex Mira, researcher at the Higher Public Health Research Centre (CSISP-GVA).

The most common bacterial genera in the colostrum samples were Weissella, Leuconostoc, Staphylococcus, Streptococcus and Lactococcus. In the fluid developed between the first and sixth month of breastfeeding, bacteria typical of the oral cavity were observed, such as Veillonella, Leptotrichia and Prevotella....The study also reveals that the milk of overweight mothers or those who put on more weight than recommended during pregnancy contains a lesser diversity of species.

The type of labour also affects the microbiome within the breast milk: that of mothers who underwent a planned caesarean is different and not as rich in microorganisms as that of mothers who had a vaginal birth. However, when the caesarean is unplanned (intrapartum), milk composition is very similar to that of mothers who have a vaginal birth.

These results suggest that the hormonal state of the mother at the time of labour also plays a role: "The lack of signals of physiological stress, as well as hormonal signals specific to labour, could influence the microbial composition and diversity of breast milk," state the authors.

And yes, what you eat while breastfeeding has an effect on the breast milk. From Science Daily:  Carotenoid levels in breast milk vary by country, diet

A Purdue University-led analysis of breast milk concludes that levels of health-promoting compounds known as carotenoids differ by country, with the U.S. lagging behind China and Mexico, a reflection of regional dietary habits. Carotenoids are plant pigments that potentially play functional roles in human development and are key sources of vitamin A, an essential component of eye health and the immune system.

The carotenoid content of a woman's breast milk is determined by her consumption of fruits and vegetables such as squash, citrus, sweet potatoes and dark, leafy greens.

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Published on 2 Comments on Good Books About the Human Microbiome

Recently several good books have been published about the community of microbes within us - our microbiota or microbiome. Originally I mainly saw the term human microbiome used everywhere. It referred to all the organisms living within and on us that are identified by their genomes (genetic material within the organism such as DNA and RNA). However, recently I'm seeing the term microbiota being used more. The microbiota refers to the community of microbes within and on us. Think of it this way: the human microbiota is the collection of all the microbes within and on us, and their genes are called the human microbiome. So there's a difference, but both refer to all the microbes within and on us.

The human body contains over 10 times more microbial cells than human cells - thus 90% microbes (about 100 trillion microbial cells), and 10% human cells (about ten trillion human cells). It is estimated that the weight of all these microbes in an adult is about 3 pounds, which is about the weight of the adult human brain. Different communities of microbes live in different parts of the body - and each little part of the body has its own ecosystem or community. And there is variation from person to person in the types of microbes in each niche in the body. So knowing all this, it is time that to stop thinking about yourself as ME or I, but more of a collective WE.

It is great to see some recently published books that explore this new and emerging field, discuss the importance of feeding and nurturing the microbes (and how), look at current and future medical uses of microbes. Because that's the exciting stuff. As I've been posting all along, our microbes seem to be intimately linked with our health - whether cancer or sinusitis (think how Lactobacillus sakei successfully treats chronic sinusitis) or many other ailments. I enjoyed all the books, I liked that the material was presented a little differently (as well as some different material) by each author, and that each book had reference lists.

Martin Blaser, MD - Missing Microbes: How the Overuse of Antibiotics is Fueling Our Modern Plagues   This is the most scholarly of the books (published 2014, and with lots of references), because he is writing not just from his own extensive personal and professional experiences, but also as director of the New York University Human Microbiome Program. He discusses the dangers of some modern medical advances (such as frequent use of antibiotics and Cesarean sections)  to the human microbiome and how this may ultimately result in various diseases (modern plagues). I have posted about him various times, including an NPR interview about his book. The CDC (Centers for Disease Control) book review page also said: "Despite his emphasis on missing microbes, however, Blaser is wary of using probiotics, prebiotics, and synbiotics to restore microbial balance. He reasonably cites the challenges arising from the unsubstantiated claims of manufacturers and the paucity of well-designed trials to evaluate probiotics."

Justin Sonnenburg and Erica Sonnenburg, PhDs - The Good Gut: Taking Control of Your Weight, Your Mood, and Your Long-term Health This interesting book written is  meant for the general reader, and they incorporate their personal stories (they are both PhDs working at Stanford University while raising 2 children) as well as what the latest microbiota research is regarding our health and bodies. They make the case that "caring for our gut microbes may be the most important health choice we make". They, like Dr. Blaser, argue that our microbiota are in peril from changes to the diet, overuse of antibiotics, and oversterilization, and is facing a "mass extinction event" which is leading to a number of modern ailments (allergies, asthma, etc). They even provide some menus and recipes to feed our microbes, recipes that stress dietary fiber. Some posts in the past year mentioned his research (especially the importance of dietary fiber in health).

Alanna Collen -  10% Human: How Our Body's Microbes Hold the Key to Health and Happiness  (Published 2015) This book is written in a chatty style by Alanna Collen, a British science writer with a PhD in evolutionary biology. She incorporates both her personal story and experiences with the scientific literature. There was much to like about the book and that it was "easy to read", but there were a few moments that I thought that the research in a discussion was incomplete (urinary tract infections come to mind).

This last one I haven't yet read, but Dr. Rob Knight is such a BIG name in this emerging field  (and I heard his wonderful lectures in the Coursera course on the human microbiome) that I'm including this TED talk book. He is also a co-founder of the American Gut Project. I've mentioned his work in a number of posts this past year. Rob Knight with Brendan Buhler - Follow Your Gut: The Enormous Impact of Tiny Microbes (TED BOOKS) (Published 2015)