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More long-standing medical advice goes out the window. New advice: avoid diet soda and artificial sweeteners. The amazing part is that our gut bacteria are involved.

From Science Daily: Certain gut bacteria may induce metabolic changes following exposure to artificial sweeteners

Artificial sweeteners -- promoted as aids to weight loss and diabetes prevention -- could actually hasten the development of glucose intolerance and metabolic disease, and they do so in a surprising way: by changing the composition and function of the gut microbiota -- the substantial population of bacteria residing in our intestines. These findings, the results of experiments in mice and humans, ...says that the widespread use of artificial sweeteners in drinks and food, among other things, may be contributing to the obesity and diabetes epidemic that is sweeping much of the world.

For years, researchers have been puzzling over the fact that non-caloric artificial sweeteners do not seem to assist in weight loss, with some studies suggesting that they may even have an opposite effect.

Next, the researchers investigated a hypothesis that the gut microbiota are involved in this phenomenon. They thought the bacteria might do this by reacting to new substances like artificial sweeteners, which the body itself may not recognize as "food." Indeed, artificial sweeteners are not absorbed in the gastrointestinal tract, but in passing through they encounter trillions of the bacteria in the gut microbiota.

The researchers treated mice with antibiotics to eradicate many of their gut bacteria; this resulted in a full reversal of the artificial sweeteners' effects on glucose metabolism. Next, they transferred the microbiota from mice that consumed artificial sweeteners to "germ-free," or sterile, mice -- resulting in a complete transmission of the glucose intolerance into the recipient mice. This, in itself, was conclusive proof that changes to the gut bacteria are directly responsible for the harmful effects to their host's metabolism.... A detailed characterization of the microbiota in these mice revealed profound changes to their bacterial populations, including new microbial functions that are known to infer a propensity to obesity, diabetes, and complications of these problems in both mice and humans.

Does the human microbiome function in the same way? Dr. Elinav and Prof. Segal had a means to test this as well. As a first step, they looked at data collected from their Personalized Nutrition Project (www.personalnutrition.org), the largest human trial to date to look at the connection between nutrition and microbiota. Here, they uncovered a significant association between self-reported consumption of artificial sweeteners, personal configurations of gut bacteria, and the propensity for glucose intolerance. They next conducted a controlled experiment, asking a group of volunteers who did not generally eat or drink artificially sweetened foods to consume them for a week, and then undergo tests of their glucose levels and gut microbiota compositions.

The findings showed that many -- but not all -- of the volunteers had begun to develop glucose intolerance after just one week of artificial sweetener consumption. The composition of their gut microbiota explained the difference: the researchers discovered two different populations of human gut bacteria -- one that induced glucose intolerance when exposed to the sweeteners, and one that had no effect either way. Dr. Elinav believes that certain bacteria in the guts of those who developed glucose intolerance reacted to the chemical sweeteners by secreting substances that then provoked an inflammatory response similar to sugar overdose, promoting changes in the body's ability to utilize sugar.

This image depicts gut microbiota. Credit: Weizmann Institute of Science

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Another study finding health benefits from eating dairy foods (vs not eating any dairy foods).

From Science Daily: A heart-felt need for dairy food: Small serving beneficial, large not necessary

A daily small serve of dairy food may reduce the risk of heart disease or stroke, even in communities where such foods have not traditionally formed part of the diet according to new research.

A study of nearly 4000 Taiwanese, led by Emeritus Professor Mark Wahlqvist from Monash University's Department of Epidemiology and Preventive Medicine and the Monash Asia Institute, considered the role increased consumption of dairy foods had played in the country's gains in health and longevity.

"We observed that increased dairy consumption meant lower risks of mortality from cardiovascular disease, especially stroke, but found no significant association with the risk of cancer," Professor Wahlqvist said.

Milk and other dairy foods are recognised as providing a broad spectrum of nutrients essential for human health. According to the study findings, people only need to eat small amounts to gain the benefits.

"Those who ate no dairy had higher blood pressure, higher body mass index and greater body fatness generally than other groups. But Taiwanese who included dairy food in their diet only three to seven times a week were more likely to survive than those who ate none."

For optimal results, the key is daily consumption of dairy foods -- but at the rate of about five servings over a week. One serving is the equivalent to eight grams of protein: a cup of milk, or 45 grams of cheese. Such quantities rarely cause trouble even for people considered to be lactose intolerant, Professor Wahlqvist said.

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These results go against the medical advice we've been hearing for years (why am I not surprised?). The new advice: High-fat dairy  yes, low-fat dairy no. I also think processed meat (with nitrates) should not be lumped together with unprocessed meat. From Science Daily:

Consumption of high-fat dairy products associated with lower risk of developing diabetes

People with the highest consumption of high-fat dairy products -- eight or more portions per day -- have a 23 percent lower risk of developing type 2 diabetes (T2D) than those with the lowest consumption -- one or less per day, a new study shows.

The study included 26 930 individuals (60% women), aged 45-74 years, from the population-based Malmö Diet and Cancer cohort. Dietary data was collected with a modified diet history method. During 14 years of follow up, 2860 incident T2D cases were identified. 

The researchers found that high intake of high-fat dairy products was associated with a 23% lower incidence of T2D for the highest consuming 20% of participants (or quintile) (median=8 portions/day) compared with the lowest consuming 20% (median=1 portion/day).

In contrast to these findings, there was no association found between intakes of low-fat dairy products and risk of developing type 2 diabetes.

High intakes of meat and meat products were, regardless of fat content, associated with increased risk, but the increased risk was higher for lower fat meats (increased risk of type 2 diabetes for high fat meats 9%, for low fat 24%), both referring to the risk in the highest-consuming versus lowest-consuming 20%). The highest consuming group for the high-fat meat had 90g or more per day, and for the low-fat meat 80g per day.

Same research, some extra details in write-up. From Medscape:

Big Intake of High-Fat Dairy May Be Protective for Diabetes

Previous research led by Nita Forouhi, MD, program leader and public-health physician at the MRC Epidemiology Unit, University of Cambridge, United Kingdom, published in August this year, suggested that molecules with odd numbers of carbon atoms (15 and 17), which are found in dairy products such as yogurt, cheese, and milk, appeared to have a protective effect.

This contrasts with evidence suggesting that even-chain saturated fatty acids, as found in alcohol or margarine, are associated with a greater risk for type 2 diabetes.

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This exciting new research is just the beginning knowledge about our virome (the virus community within us). Note that they only looked at viruses in a few areas of our bodies - the rest is still a mystery. But note that it is normal for healthy individuals to carry viruses, and that we have "distinct viral fingerprints". We don't know if the viruses are beneficial or not to us at this time. From Science Daily:

Healthy humans make nice homes for viruses

The same viruses that make us sick can take up residence in and on the human body without provoking a sneeze, cough or other troublesome symptom, according to new research. On average, healthy individuals carry about five types of viruses on their bodies, the researchers report. The study is the first comprehensive analysis to describe the diversity of viruses in healthy people.

The research was conducted as part of the Human Microbiome Project, a major initiative funded by the National Institutes of Health (NIH) that largely has focused on cataloging the body's bacterial ecosystems. ..."Lots of people have asked whether there is a viral counterpart, and we haven't had a clear answer. But now we know there is a normal viral flora, and it's rich and complex."

In 102 healthy young adults ages 18 to 40, the researchers sampled up to five body habitats: nose, skin, mouth, stool and vagina. The study's subjects were nearly evenly split by gender.

At least one virus was detected in 92 percent of the people sampled, and some individuals harbored 10 to 15 viruses...."We only sampled up to five body sites in each person and would expect to see many more viruses if we had sampled the entire body."

Scientists led by George Weinstock, PhD, at Washington University's Genome Institute, sequenced the DNA of the viruses recovered from the body, finding that each individual had a distinct viral fingerprint. (Weinstock is now at The Jackson Laboratory in Connecticut.) About half of people were sampled at two or three points in time, and the researchers noted that some of the viruses established stable, low-level infections.

The researchers don't know yet whether the viruses have a positive or negative effect on overall health but speculate that in some cases, they may keep the immune system primed to respond to dangerous pathogens while in others, lingering viruses increase the risk of disease.

Study volunteers were screened carefully to confirm they were healthy and did not have symptoms of acute infection. They also could not have been diagnosed in the past two years with human papillomavirus infection (HPV), which can cause cervical and throat cancer, or have an active genital herpes infection.

Analyzing the samples, the scientists found seven families of viruses, including strains of herpes viruses that are not sexually transmitted. For example, herpesvirus 6 or herpesvirus 7 was found in 98 percent of individuals sampled from the mouth. Certain strains of papillomaviruses were found in about 75 percent of skin samples and 50 percent of samples from the nose. Novel strains of the virus were found in both sites.

Not surprisingly, the vagina was dominated by papillomaviruses, with 38 percent of female subjects carrying such strains. Some of the women harbored certain high-risk strains that increase the risk of cervical cancer. These strains were more common in women with communities of vaginal bacteria that had lower levels of Lactobacillus and an increase in bacteria such as Gardnerella, which is associated with bacterial vaginosis.

Adenoviruses, the viruses that cause the common cold and pneumonia, also were common at many sites in the body.

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Excerpts from an article by Jane Brody in the NY Times:

Beating Back the Risk of Diabetes

This year, nearly two million American adults and more than 5,000 children and adolescents will learn they have a potentially devastating, life-shortening, yet largely preventable disease: Type 2 diabetes. They will join 29.1 million Americans who already have diabetes.

Diabetes and its complications are responsible for nearly 200,000 deaths a year; the fatality rate among affected adults is 50 percent higher than among similar people without diabetes. Alarmingly, recent studies even have linked diabetes to an increased risk of dementia and Alzheimer's disease. Even people with above-average blood glucose levels, but not diabetes, have an elevated risk.

The Diabetes Prevention Program study, conducted among about 3,800 people who had pre-diabetes, found that moderate weight loss — an average of 12 pounds —  reduced the odds of progression to diabetes by nearly 50 percent.

An excellent discussion of what is known about the effect on diabetes of various foods and supplements appeared recently in Nutrition Action Healthletter at cspinet.org/iceberg.pdf. Some highlights:

Carbohydrates - breads, grains, cereals, sugary drinks and sweets of all kinds — are most problematic for people with diabetes or at risk of developing it. Carbohydrates are eventually metabolized to glucose, which raises the body’s demand for insulin. Consume less of them in general, and choose whole-grain versions whenever possible.

If you must have sweet drinks, select artificially sweetened ones. In two huge studies of nurses and other health professionals who were followed for 22 years, those who drank one or more sugary soft drinks a day had about a 30 percent higher risk of developing diabetes than those who rarely drank them, even after their weight was taken into account.

But there’s good news about coffee. Two or three cups of coffee (but not tea) a day, with or without caffeine, have been consistently linked to a lower risk of Type 2 diabetes. 

For protein, limit consumption of red meat, especially processed meats like sausages, hot dogs and luncheon meats, which are linked to a higher diabetes risk. Instead, choose fish, lean poultry (skinless and not fried), beans and nuts. Low-fat dairy products, including yogurt, and even fatty ones may lower the risk of diabetes; the reason is unclear.

Most protective are green, leafy vegetables — spinach, chard, kale, collards, mustard greens and even lettuce — as well as cruciferous vegetables like cabbage, broccoli and cauliflower. But all vegetables are good and should fill at least two-thirds of your dinner plate.

The nutrients magnesium and vitamin D are also potentially protective. In fact, the preventive value of leafy greens, whole grains, beans and nuts may lie in their high magnesium content. In a well-designed clinical trial of 32 overweight people with insulin resistance, the prelude to diabetes, blood glucose levels and insulin sensitivity improved in those who took a daily magnesium supplement for six months. Don’t go overboard: More than 350 milligrams of magnesium daily can cause diarrhea. 

Vitamin D, long known to be crucial to healthy bones, may also be helpful. In one study of 92 overweight or obese adults with prediabetes, those who took a supplement of 2,000 international units of vitamin D daily had better function of the pancreatic cells that produce insulin..

Of course, how much you weigh and what you eat are not the only concerns. Regular, preferably daily, physical exercise is a vital component of any prevention and treatment program for Type 2 diabetes, or most any chronic ailment. Weight loss can reduce diabetes risk by about 50 percent, but adding exercise to that can lower the odds by 70 percent, compared with people who remain overweight and inactive, according to a study that followed nearly 85,000 female nurses for 16 years. Women who were active for seven or more hours weekly had half the risk of developing diabetes as did women who exercised only a half-hour a week.

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From Science Daily:

High protein diets lead to lower blood pressure, study finds

Adults who consume a high-protein diet may be at a lower risk for developing high blood pressure, concludes a study that found participants consuming the highest amount of protein -- an average of 100 g protein/day -- had a 40 percent lower risk of having high blood pressure compared to the lowest intake level.

One of three U.S. adults has hypertension and 78.6 million are clinically obese, a risk factor for the development of hypertension. Because of the strain that it puts on blood vessel walls, HBP is one of the most common risk factors of stroke and an accelerator of multiple forms of heart disease, especially when paired with excess body weight.

The researchers analyzed protein intakes of healthy participants from the Framingham Offspring Study and followed them for development of high blood pressure over an 11-year period. They found that adults who consumed more protein, whether from animal or plant sources, had statistically significantly lower systolic blood pressure and diastolic blood pressure levels after four years of follow-up. In general, these beneficial effects were evident for both overweight (BMI ≥25 kg/m2) and normal weight (BMI <25 kg/m2) individuals. They also found that consuming more dietary protein also was associated with lower long-term risks for HBP. When the diet also was characterized by higher intakes of fiber, higher protein intakes led to 40-60 percent reductions in risk of HBP.

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Two studies about blood pressure and how it can be easily changed without medications. From Science Daily:

Small weight gain can raise blood pressure in healthy adults

Gaining a few pounds can increase blood pressure in healthy adults, researchers report. Increased fat inside the abdomen led to even larger increases in blood pressure, their study results showed. Many people understand the health dangers of large amounts of extra body weight, but researchers in this study wanted to see the impact of a small weight gain of about five to 11 pounds.

At the beginning of the eight-week study, a 24-hour monitor tested the blood pressure of 16 normal weight people. Their results were compared to 10 normal weight, healthy people who maintained the same weight over the eight weeks. Researchers found: -Those who gained weight had a systolic blood pressure (top number) increase from an average 114 mm Hg to an average 118 mm Hg. -Those who gained more weight inside their abdomen had a greater blood pressure increase. -A five to 11 pound weight gain didn't change cholesterol, insulin or blood sugar levels. The study was conducted in healthy people ages 18-48. 

From Science Daily:

Restricting calories may improve sleep apnea, blood pressure in obese people

Restricting calories may improve sleep apnea and reduce blood pressure in obese adults. Those who restricted their calories had higher levels of oxygen in their blood and a greater reduction in body weight, a study has demonstrated.

 "Losing weight was most likely the key to all the benefits observed in the calorie-restricted group. A greater reduction in systolic blood pressure can be explained, at least partially, by the reduction in body weight that was associated with reduction in obstructive sleep apnea severity and sympathetic nervous system activity." Systolic blood pressure is the top number in a blood pressure reading, which measures the force of the blood in the arteries when the heart is contracted.

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Amazing possibilities, but more studies needed. The key finding: A diversity of the bacterial community in the gut is good, and perhaps can be altered through diet, and so perhaps alter the future risk of developing breast cancer.From Science Daily:

Diverse gut bacteria associated with favorable ratio of estrogen metabolites

Postmenopausal women with diverse gut bacteria exhibit a more favorable ratio of estrogen metabolites, which is associated with reduced risk for breast cancer, compared to women with less microbial variation, according to a new study.

Since the 1970s, it has been known that in addition to supporting digestion, the intestinal bacteria that make up the gut microbiome influence how women's bodies process estrogen, the primary female sex hormone. The colonies of bacteria determine whether estrogen and the fragments left behind after the hormone is processed continue circulating through the body or are expelled through urine and feces. Previous studies have shown that levels of estrogen and estrogen metabolites circulating in the body are associated with risk of developing postmenopausal breast cancer.

"In women who had more diverse communities of gut bacteria, higher levels of estrogen fragments were left after the body metabolized the hormone, compared to women with less diverse intestinal bacteria," said one of the study's authors, James Goedert, MD, of the National Institutes of Health's National Cancer Institute (NCI) in Bethesda, MD. "This pattern suggests that these women may have a lower risk of developing breast cancer."

As part of the cross-sectional study, researchers analyzed fecal and urine samples from 60 postmenopausal women enrolled in Kaiser Permanente Colorado. .

"Our findings suggest a relationship between the diversity of the bacterial community in the gut, which theoretically can be altered with changes in diet or some medications, and future risk of developing breast cancer," Goedert said. 

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Good news! From Science Daily:

Taking short walking breaks found to reverse negative effects of prolonged sitting

Three easy -- one could even say slow -- 5-minute walks can reverse harm caused to leg arteries during three hours of prolonged sitting, researchers report. Sitting for long periods of time is associated with risk factors such as higher cholesterol levels and greater waist circumference that can lead to cardiovascular and metabolic disease. When people sit, slack muscles do not contract to effectively pump blood to the heart. Blood can pool in the legs and affect the endothelial function of arteries, or the ability of blood vessels to expand from increased blood flow.

The researchers were able to demonstrate that during a three-hour period, the flow-mediated dilation, or the expansion of the arteries as a result of increased blood flow, of the main artery in the legs was impaired by as much as 50 percent after just one hour. The study participants who walked for 5 minutes each hour of sitting saw their arterial function stay the same -- it did not drop throughout the three-hour period. Thosar says it is likely that the increase in muscle activity and blood flow accounts for this.

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An opinion piece from Dr. David Johnson, Prof. of Medicine and Chief of Gastroenterology at Eastern Medical School in Norfolk, Virginia but an interesting one that points out the limitations of current probiotic knowledge and that we shouldn't blindly take probiotics (with only a few bacteria strains) after antibiotic use thinking that they're all good, all the time. I'm including this article to show what many medical professionals think about probiotic use and why.

He discusses 2 large studies, but unfortunately both studies only looked at hospitalized patients - and the large PLACIDE study looked at over-65 year old patients. And in the second large study he discusses the benefits of the antibiotic metronidazole.

I agree with his need for caution and the need for more large studies, but I wish he had discussed children, people NOT hospitalized, people who just had a round of antibiotics without life threatening complications, and not dismissed small studies. Hospitalized vs non-hospitalized people are very, very different groups. Small studies are finding benefits of various bacteria, but yes, the research is in its infancy, especially what are "normal microbial communities" in the gut and in other parts of the body. He does not discuss fecal transplants of entire microbial communities for C. difficile and their over 90% success rate. Dr. S. Lynch has theorized that some bacteria act as "keystone species" that could help repopulate a biome after an insult (such as antibiotics). From Medscape:

Probiotics: Help or Harm in Antibiotic-Associated Diarrhea?

Today I want to discuss the issue of probiotics, and whether probiotics are doing an element of benefit or an element of harm. With access to over-the-counter products, use of probiotics has dramatically increased. Physicians recommend probiotics routinely to patients when they are taking antibiotics to prevent antibiotic-associated diarrhea. I would like to take a time-out and reevaluate what we are doing for these patients.

Not infrequently, antibiotics are associated with Clostridium difficile infections, which occur in up to one third of patients with antibiotic-associated diarrhea.

In 2012, highly publicized meta-analyses were published in JAMA [1] and Annals of Internal Medicine. [2]These studies, and a Cochrane review,[3] suggest that not only can probiotics prevent or diminish antibiotic-associated diarrhea, but probiotics may also be helpful in avoiding C difficile infection.

Enter the most recent study, which is called the PLACIDE study, from the United Kingdom[4] It involved 5 hospitals, 68 different medical and surgical units, and more than 17,000 patients aged 65 years or older. All patients were hospitalized and taking an antibiotic.

These patients were randomly assigned, if they met eligibility criteria, to receive either a microbial preparation (which is the term they used for "probiotic") or an identical placebo. The microbial preparation had 2 strains of Lactobacillus and 2 strains of bifidobacteria, which patients received for 21 days.... Even with evaluation for intention to treat, there was no difference in the outcomes for C difficile infection or antibiotic-associated diarrhea between the microbial preparation (probiotic) and placebo group. Of interest, there was an increase in flatus in the microbial preparation group, and patients with C difficile diarrhea who received the microbial preparation reported a 3-fold increase in bloating. 

Although intended to restore good health, we are seeing a dysbiosis. We have disrupted the microflora in the gut, and are trying to jam it back with strains of bacteria that we think are good bacteria, and it may not be the correct answer. We don't know the right answer. When you alter the microflora, you change some of the metabolism of carbohydrates, bile salts, and complex sugars. We are not clear whether jamming the gut with another strain of bacteria is going to be of benefit.

I want to posit an element of potential harm, and not rush in to recommend probiotics routinely in patients to whom you prescribe antibiotics. I would also caution you not to use probiotics in patients in the intensive care unit, or in any patient with an indwelling prosthesis, particularly an intravascular prosthesis.