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Author: Sima

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Another excellent reason to exercise - for better erectile and sexual function in men! The researchers say that their research supports the idea that "that exercise might one day be prescribed as a treatment for erectile dysfunction".

And they're not talking about that much exercise: the highly active men in the study did a moderately intense activity such as brisk walking, cycling, or tennis at least an hour 3 to 4 times a week. Other research has suggested that erectile dysfunction can be reversed naturally by changing lifestyle factors see October 27, 2014 post Reversing Erectile Dysfunction Naturally). From Reuters:

Older men who exercise more have better erectile function

Men who exercise more have better erectile and sexual function, suggests a small study of older overweight men. The authors say their results support the idea that exercise might one day be prescribed as a treatment for erectile dysfunction.

Vidal and colleagues examined exercise habits and sexual function in 295 healthy men who were part of a research project evaluating prostate cancer risk at the Durham Veterans Affairs Medical Center in North Carolina. On average, the men were about 62 years old, and they were all overweight or obese. Roughly one third had diabetes or a history of chest pain or heart attacks. About three quarters were current or former smokers. Ninety-three men, or about a third of the group, were African-American.

Men were scored based on a measure known as metabolic equivalent of task (MET) hours per week and placed in four categories ranging from sedentary, with three or fewer MET hours/week, to highly active, with at least 18 MET hours/week. Most often, the men were sedentary, with 44 percent reporting little activity. But a substantial proportion, 26 percent, were highly active.Researchers also questioned the men about their sexual function, focusing on their ability to get erections and have orgasms, as well as the quality and frequency of their erections...Added up, responses could lead to a total score from 0 to 100....Men who reported more frequent exercise also reported higher sexual function scores. Half of the highly active men reported sexual function scores of at least 70, compared with a median score of about 33 for sedentary men.

SOURCE: bit.ly/1NilZYI The Journal of Sexual Medicine, online March 20, 2015.

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People have asked me if it is healthy to exercise or ride a bicycle in the congested and polluted New York metro area. According to this much quoted in the past week study from the University of Copenhagen - it is better to exercise than not in polluted cities when looking at death rates. But is their air pollution even comparable to ours? What does it do to our lungs to bicycle daily behind smoke belching buses?

Even the researcher said:"It is also important to note that these results pertain to Denmark and sites with similar air pollution levels, and may not necessary be true in cities with several fold higher air pollution levels, as seen in other parts of the world." They also stated: "...we would still advise people to exercise and cycle in green areas, parks, woods, with low air pollution and away from busy roads, when possible." From Science Daily:

Exercise can outweigh harmful effects of air pollution

The beneficial effects of exercise are more important for our health than the negative effects of air pollution, in relation to the risk of premature mortality, new research shows. In other words, benefits of exercise outweigh the harmful effects of air pollution.The study shows that despite the adverse effects of air pollution on health, air pollution should be not perceived as a barrier to exercise in urban areas. "Even for those living in the most polluted areas of Copenhagen, it is healthier to go for a run, a walk or to cycle to work than it is to stay inactive," says Associate Professor Zorana Jovanovic Andersen from the Centre for Epidemiology and Screening at the University of Copenhagen.

It is well known that physical activity reduces, while air pollution increases the risk of premature mortality. Physical activity amplifies respiratory intake and accumulation of air pollutants in our lungs, which may increase the harmful effects of air pollution during exercise."However, we would still advise people to exercise and cycle in green areas, parks, woods, with low air pollution and away from busy roads, when possible," she adds.

The Danish study includes 52,061 subjects, aged 50-65 years, from the two main cities Aarhus and Copenhagen, who participated in the cohort study Diet, Cancer and Health..,5,500 participants died before 2010, and the researchers observed about 20% fewer deaths among those who exercised than among those who didn't exercise, even for those who lived in the most polluted areas, in central Copenhagen and Aarhus, or close to busy roads and highways.

"It is also important to note that these results pertain to Denmark and sites with similar air pollution levels, and may not necessary be true in cities with several fold higher air pollution levels, as seen in other parts of the world," concludes Andersen.

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Note that both eggs and high-fat dairy products were basically considered evil by the medical establishment for many years. Remember egg white omelettes?And now both are thought to have health benefits, especially reducing the risk of diabetes. From Science Daily:

Eating eggs reduces risk of type 2 diabetes, study indicates

Egg consumption may reduce the risk of type 2 diabetes, according to new research...Research has shown that lifestyle habits, such as exercise and nutrition, play a crucial role in the development of the disease. A new study has found that egg consumption was associated with a lower risk of type 2 diabetes as well as with lower blood glucose levels. Men who ate approximately four eggs per week had a 37 per cent lower risk of type 2 diabetes than men who only ate approximately one egg per week. This association persisted even after possible confounding factors such as physical activity, body mass index, smoking and consumption of fruits and vegetables were taken into consideration. The consumption of more than four eggs did not bring any significant additional benefits.

The dietary habits of 2,332 men aged between 42 and 60 years were assessed at the baseline of the Kuopio Ischaemic Heart Disease Risk Factor Study, KIHD, at the University of Eastern Finland in 1984-1989. During a follow-up of 19.3 years, 432 men were diagnosed with type 2 diabetes.

Also note that high meat consumption is linked to higher risk of diabetes. From Science Daily:

High-fat dairy products linked to reduced type 2 diabetes risk

Consumption of high-fat yoghurt and cheese are linked to a reduction in the risk of type 2 diabetes by as much as a fifth, according to new research. High meat consumption, on the other hand, is linked to a higher risk.

However, the new study indicates that it is high-fat dairy products specifically that are associated with reduced risk."Those who ate the most high-fat dairy products had a 23 per cent lower risk of developing type 2 diabetes than those who ate the least. High meat consumption was linked to an increased risk of type 2 diabetes regardless of the fat content of the meat," said Ulrika Ericson, who conducted the study.

The researchers studied the eating habits of 27,000 individuals aged 45 to 74. The participants took part in the Malmö Diet and Cancer study in the early 1990s, in which they provided details of their eating habits. Twenty years on, over ten per cent -- 2 860 people -- had developed type 2 diabetes.

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After reading this article, I looked over my last year's posts and realized that the recent studies posted all found that eating fish showed health benefits (and they did not look at supplements). Once again, a food shows benefits while the supplement is debatable. Current advice: try to eat fish at least twice a week. From the NY Times:

Fish Oil Claims Not Supported by Research

Fish oil is now the third most widely used dietary supplement in the United States, after vitamins and minerals, according to a recent report from the National Institutes of Health. At least 10 percent of Americans take fish oil regularly, most believing that the omega-3 fatty acids in the supplements will protect their cardiovascular health. But there is one big problem: The vast majority of clinical trials involving fish oil have found no evidence that it lowers the risk of heart attack and stroke.

From 2005 to 2012, at least two dozen rigorous studies of fish oil were published in leading medical journals, most of which looked at whether fish oil could prevent cardiovascular events in high-risk populations. These were people who had a history of heart disease or strong risk factors for it, like high cholesterol, hypertension or Type 2 diabetes. All but two of these studies found that compared with a placebo, fish oil showed no benefit.

In theory at least, there are good reasons that fish oil should improve cardiovascular health. Most fish oil supplements are rich in two omega-3 fatty acids — eicosapentaenoic acid (EPA) and docosahexaenoic acid (DHA) — that can have a blood-thinning effect, much like aspirin, that may reduce the likelihood of clots. Omega-3s can also reduce inflammation, which plays a role in atherosclerosis. And the Food and Drug Administration has approved at least three prescription types of fish oil — Vascepa, Lovaza and a generic form — for the treatment of very high triglycerides, a risk factor for heart disease. But these properties of omega-3 fatty acids have not translated into notable benefits in most large clinical trials.

Like many cardiologists, Dr. Stein encourages his patients to avoid fish oil supplements and focus instead on eating fatty fish at least twice a week, in line with federal guidelines on safe fish intake, because fish contains a variety of healthful nutrients other than just EPA and DHA. “We don’t recommend fish oil unless someone gets absolutely no fish in their diets,” Dr. Stein said.

But some experts say the case for fish oil remains open. Dr. JoAnn Manson, the chief of preventive medicine at Brigham and Women’s Hospital in Boston, said the large clinical trials of fish oil focused only on people who already had heart disease or were at very high risk. Fish oil has also been promoted for the prevention of a variety of other conditions, including cancer, Alzheimer’s and depression. Dr. Manson is leading a five-year clinical trial, called the Vital study, of 26,000 people who are more representative of the general population. Set to be completed next year, it will determine whether fish oil and vitamin D, separately or combined, have any effect on the long-term prevention of heart disease, Type 2 diabetes, and other diseases in people who do not have many strong risk factors.

Dr. Manson says that although she recommends eating fatty fish first, she usually does not stop people from taking fish oil, in part because it does not seem to have major side effects in generally healthy people. “But I do think people should realize that the jury is still out,” she said, “and that they may be spending a lot of money on these supplements without getting any benefit.”

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The research finding that eating fruits and vegetables with high pesticide residues has a negative effect on sperm is disturbing. It wasn't the amount of fruits and vegetables eaten, it was eating fruits and vegetables with high levels of pesticide residues. Yes, the study does have some limitations (for example, a one time analysis, looked at men at a fertility clinic and not the general population), but...even with these limitations, the results are disturbing.

Earlier studies of children showed that switching to an organic diet has almost immediate results of reducing pesticide residues in the body (OP Pesticides in Children’s Bodies: The Effects of a Conventional versus Organic Diet). So the advice here is try to increase the amounts of organic fruits and vegetables in the diet, especially those with high pesticide residue levels.

Fruit or vegetables that were low in pesticide residues included peas, beans, grapefruit and onions. Those that had highest pesticide residues included peppers, spinach, strawberries, celery,blueberries, potatoes, peaches, plums, apples and pears.

From Time: A Diet High in Pesticides Is Linked to a Lower Sperm Count

The troubling link between pesticide exposure and fertility isn’t new; scientists have already established that people who work with pesticides tend to have lower fertility than people who don’t. But for the majority of us who don’t work with chemicals, diet is the biggest source of exposure, says Jorge Chavarro, MD, assistant professor of nutrition and epidemiology at Harvard School of Public Health and senior author of a new study published in the journal Human Reproduction.

Chavarro and his colleagues wanted to see if pesticide residues left on fruits and vegetables might have a similar effect on sperm—and their findings suggest that they did. Men who ate fruits and vegetables with a lot of pesticides had lower sperm counts and more oddly shaped sperm than those who had lower levels of dietary pesticide exposure.

Over an 18-month period, the researchers used data from the Environment and Reproductive Health (EARTH) study, including semen samples from 155 men who were being treated at a Boston fertility clinic and a food frequency questionnaire they completed. The researchers determined pesticide exposure by comparing the questionnaire answers with government data about produce pesticide levels in the USDA’s Pesticide Data Program.

The study didn’t tease out individual foods, but the researchers classified produce according to whether it had high or low-to-moderate levels of pesticides. Men who ate the most high-pesticide fruits and vegetables had a 49% lower total sperm count and 32% fewer sperm that were shaped normally, compared to men who ate the least amount of the high-pesticide produce.

Researchers gave each piece of produce a score based on its level of detectable pesticides, its level of pesticides that exceeded the tolerance level established by the U.S. Environmental Protection Agency, and whether the produce had three or more types of detectable pesticides. (The bigger the score, the more it hit all three measures.) Ranked from highest pesticide contamination to lowest, here were the top fruits and vegetables: Green, yellow and red peppers (6), Spinach (6), Strawberries (6), Celery (6), Blueberries (5), Potatoes (5), Peaches and plums (5), Apples or pears (5), Winter squash (4), Kale, mustard greens and chard greens (4), Grapes and raisins (4).

The team didn’t tease out associations with individual pesticides. But they believe that a mixture of pesticides—not just one particular pesticide—is responsible for the link. The strongest variable in their analysis were the proportion of fruits and vegetables consumed that use three or more pesticides. “The more pesticides are applied on any particular crop, that seems to be having a bigger impact,” Chavarro says...But for people who are concerned about their dietary exposure to pesticides, there are ways to lower it, he says, like eating organic and choosing produce not listed on the Environmental Working Group’s dirty dozen list.

From Science  Daily: Pesticides in fruit and vegetables linked to semen quality

Assistant Professor of Nutrition and Epidemiology at the Harvard T.H. Chan School of Public Health in Boston (USA), Jorge Chavarro, said: "These findings should not discourage the consumption of fruit and vegetables in general. In fact, we found that total intake of fruit and vegetables was completely unrelated to semen quality. This suggests that implementing strategies specifically targeted at avoiding pesticide residues, such as consuming organically-grown produce or avoiding produce known to have large amounts of residues, may be the way to go."

There were no differences seen between men in the four groups who consumed fruit and vegetables with low-to-moderate pesticide residues. In fact, there was a significant trend towards having a higher percentage of normally shaped sperm among men who consumed the most fruit and vegetables with low pesticide residues -- a relative increase of 37% from 5.7% to 7.8%...Note:Pesticide use varies from country to country, but in the USA those used on fruit and vegetables include Atrazine, Malathion, Chlorpyrifos and Carbendazim. 

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More research showing health benefits of peanuts, including when eating them with a high fat meal. From Science Daily:

Adding peanuts to a meal benefits vascular health

A study of peanut consumption showed that including them as a part of a high fat meal improved the post-meal triglyceride response and preserved endothelial function.The purpose of this research was to evaluate vascular function after a high fat meal challenge.

Fifteen overweight males were randomized to either a peanut meal containing 3 oz. of ground peanuts (as a shake) or a control meal (a shake without peanuts) that were matched for energy and macronutrients...Flow-mediated dilatation (FMD) was measured to assess vascular function... The control meal decreased FMD by 1.2 percent compared to baseline. In contrast, there was no decrease in FMD after the peanut meal. These results demonstrate that the peanut meal maintained normal vascular function whereas the high fat-matched control meal impaired vascular function acutely.

Vascular dysfunction plays a major role in the development of atherosclerosis and the formation of coronary plaques and lesions that lead to coronary artery disease. Typically after a high fat meal, vascular function is reduced, albeit temporarily, until the fat that is in the blood (from the meal) is cleared. Strategies that can blunt this response to both dietary fat and its effect on vascular dysfunction may decrease the risk of coronary disease. Our finding demonstrated that that peanut consumption was shown to be atheroprotective as a part of high fat meal.

"Previous studies have shown that individuals who consume peanuts more than two times a week have a lower risk of coronary heart disease," said Liu. "This study indicates that the protective effect of peanut consumption could be due, in part, to its beneficial effect on artery health."

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The American diet with its emphasis on highly processed foods is linked to chronic diseases. It's also not healthy when you look at the microbiome (community of microbes living in your body). With all the health research out there showing health benefits of real whole foods (especially fruits, vegetables, whole grains, seeds, legumes), then the finding that highly processed foods dominate U.S. food purchases are just plain sad. But I'm not surprised. From Science Daily:

Highly processed foods dominate U. S. grocery purchases

A nation-wide analysis of U.S. grocery purchases reveals that highly processed foods make up more than 60 percent of the calories in food we buy, and these items tend to have more fat, sugar and salt than less-processed foods.

From 2000 to 2012, the researchers asked 157,142 households to use UPC barcode scanners to record all foods and beverages they purchased from grocery stores for at least 1 year. Although items without barcodes were not included, Poti points out that packaged produce such bagged lettuce or pints of berries can be scanned. Households participated in the study for an average of four years and collectively purchased 1.2 million items. The research team then linked each item to its nutrition information, product description and ingredient list, allowing them to rank each product's degree of food processing.

The researchers classified products as highly processed if they contained multi-ingredient, industrially formulated mixtures. They labeled foods such as soda, cookies, chips, white bread, candy and prepared meals as highly processed foods and categorized fresh or frozen fruits and vegetables, milk, eggs, dried beans and fresh meat as unprocessed or minimally processed. The investigators also examined convenience, distinguishing between foods that are ready to eat, ready to heat or require cooking and/or preparation. Candy and chips are examples of ready-to-eat foods, and frozen meals are a ready-to-heat food.

"Overall, we found that not only are highly processed foods a dominant, stable part of U.S. purchasing patterns, but also that the highly-processed foods that households are purchasing are higher in fat, sugar, and salt, on average, compared to the less-processed foods that they buy," said Poti, who will present these findings at the American Society for Nutrition (ASN) Annual Meeting during Experimental Biology 2015."

The analysis revealed that from 2000 to 2012, the proportion of calories in highly processed food and beverage purchases by U.S. households remained stable at 61.0 to 62.5 percent. The researchers noted a significant increase in the proportion of calories purchased in ready-to-heat foods, which reached 15.2 percent in 2012. More than 80 percent of calories were purchased in ready-to-eat or ready-to-heat form in 2012, and these tended to be higher in fat, sugar and salt than food purchases that required preparation.

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The researchers think that repeated courses of antibiotics destroy the gut bacteria resulting in gut bacteria imbalance. From Red Orbit:

Antibiotic overuse could up diabetes risk, study says

Repeated use of some antibiotics could increase a person’s risk of developing type 2 diabetes, according to research published online Tuesday in the European Journal of Endocrinology. In the study, scientists from the University of Pennsylvania found that men and women who had ever been prescribed with at least two courses of specific types of antibiotics were more likely to eventually be diagnosed with type 2 diabetes than those who had taken no more than one.

The antibiotics used in the research came from one of four categories, according to LiveScience: penicillins, cephalosporins, quinolones and macrolides. The authors reviewed a database of UK patients, looking at the number of antibiotic prescriptions given to over 200,000 diabetic patients at least one year before those individuals were diagnosed with the condition...They found that the more courses of antibiotics that were prescribed to a person, the greater the risk that he or she would go on to develop the disease.

Patients who had been prescribed between two and five courses of penicillin increased their risk of diabetes by 8 percent, according to the Daily Mail, and the risk increased by 23 percent for those receiving more than five courses of the frequently used antibiotic versus the one- or no-course group.

Those who were given between two and five courses of quinolones, which are used to treat respiratory and urinary tract infections, had an increased diabetes risk of 15 percent, and those receiving more than five courses saw that risk shoot up by 37 percent. 

Those who were given just one course of antibiotics showed no such increase in diabetes risk, the researchers reported. Nor was there any link found between exposure to anti-virals and anti-fungals and diabetes risk. The reason for the association between frequent antibiotic use and the risk of diabetes is not clear, but may be related to a gut bacteria imbalance, they wrote.“Gut bacteria have been suggested to influence the mechanisms behind obesity, insulin resistance and diabetes in both animal and human models. Previous studies have shown that antibiotics can alter the digestive ecosystem,” added lead author Dr. Ben Boursi.

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It is important to identify protective factors as well as risk factors for cataracts because cataract surgery is the only treatment for cataracts. Cataracts are a medical condition resulting in clouding of the normally clear lens of the eye, which results in blurred vision.

From Medscape: Physical Activity May Reduce Cataract Risk

High levels of total and long-term physical activity, as well as specific types of physical activity, may decrease the risk for age-related cataract later in life, researchers report in an article published in the February issue of Ophthalmology. Of 52,660 men and women 45 to 83 years of age who completed questionnaires to assess physical activity as part of two large population-based cohorts, 11,580 developed age-related cataract during a 12-year follow-up period...

Participants with the highest quartile of physical activity had a 13% decreased risk of developing cataracts relative to those with the lowest levels of physical activity, after adjustments for multiple factors including fruit and vegetable intake, antioxidant supplement use, and alcohol intake ...In addition, increased amounts of long-term total physical activity both at 30 years of age and at the beginning of the study (mean age, 59.4 years) decreased the risk for cataract by 24% compared with low levels of activity, according to the researchers .

When the investigators looked at specific activities, they found that walking or bicycling 60 minutes per day or more decreased the risk for cataract by 12% compared with hardly ever walking or bicycling, and work or occupational activity requiring heavy manual labor decreased the risk for cataract by 16% compared with mostly sedentary occupations. Compared with individuals reporting less than 1 hour of leisure time inactivity per day, those who were physically inactive for 6 or more hours of leisure time daily were 27% more likely to develop age-related cataract, they write.

"Our results on different types of physical activity suggest that being physically active on a regular daily basis may contribute to decreased risk of cataract, rather than short weekly episodes of exercising/training," Selin explained in an interview with Medscape Medical News.

Keep in mind that statin use is linked to increased risk of cataracts. From Science Daily:

New study strengthens evidence of connection between statin use and cataracts; any risks should be weighed against benefits

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Discussions of the benefits of dietary fiber seem to be everywhere this week.

From Forbes: Eat Whole Grains For A Long Life, New Study Says

Eating lots of whole grains – especially those high in cereal fiber – may help people live longer, according to new research. The study out in BMC Medicine this week suggests that eating hefty amounts of cereal fibers can help reduce the risk of death from a number of causes, including cancer and diabetes, by almost 20%. Previous research has certainly linked whole grains to the reduction of certain chronic diseases and to reduced mortality, but this one is the largest of its kind to show a reduction in death from a number of different causes. So if you want to live longer, grab a bowl of cereal. The less refined, the better.

Whole grains are grains in their most unadulterated form, still containing the endosperm, bran, and germ – most of the plant’s nutritional value lies in the bran and germ. When grains go through milling to become processed or refined, they’re typically stripped of the bran and germ parts, along with a number of B vitamins, fiber, and iron.

In the new study, the Harvard Medical School team tracked over 367,000 healthy people who were taking part in the NIH-AARP Diet and Health Study, for an average of 14 years. ..It turned out that people who ate more whole grains – 1.2 ounces of per day, on average – had a 17% reduced risk of death, compared to those who ate much less, around 0.13 ounces per day. And when it came to the cereal fiber itself, people who ate the most had a 19% reduced risk of death from any cause, compared to those who ate the least.

The researchers even broke it down by disease: People who ate the highest amounts of whole grains had a 48% reduced risk of death from diabetes, and an 11% reduced risk of dying from respiratory diseases. And people who ate the most cereal fiber had 15% and 34% reduced risk of death from cancer and diabetes, respectively. 

The study cannot of course determine causation, since it’s just observational...Still, a number of studies have pointed to a strong connection between whole grains and improved health and longevity in recent years. It may be the anti-inflammatory properties of fiber per se – and its effect of reducing c-reactive protein (CRP) and tumor necrosis factor – that are responsible for their health benefits. If you’re going to up your grain intake, make sure to choose whole ones, like steel cut oats, quinoa, or even whole grain bread, over refined ones like cereal flakes or white bread. 

From Scientific American: Fiber-Famished Gut Microbes Linked to Poor Health

Your gut is the site of constant turf wars. Hundreds of bacterial species—along with fungi, archaea and viruses—do battle daily, competing for resources. Some companies advocate for consuming more probiotics, live beneficial bacteria, to improve microbial communities in our gut, but more and more research supports the idea that the most powerful approach might be to better feed the good bacteria we already harbor. Their meal of choice? Fiber.  

Fiber has long been linked to better health, but new research shows how the gut microbiota might play a role in this pattern. One investigation discovered that adding more fiber to the diet can trigger a shift from a microbial profile linked to obesity to one correlated with a leaner physique. Another recent study shows that when microbes are starved of fiber, they can start to feed on the protective mucus lining of the gut, possibly triggering inflammation and disease.

"Diet is one of the most powerful tools we have for changing the microbiota," Justin Sonnenburg, a biologist at Stanford University, said earlier this month at a Keystone Symposia conference on the gut microbiome. "Dietary fiber and diversity of the microbiota complement each other for better health outcomes." In particular, beneficial microbes feast on fermentable fibers—which can come from various vegetables, whole grains and other foods—that resist digestion by human-made enzymes as they travel down the digestive tract. These fibers arrive in the large intestine relatively intact, ready to be devoured by our microbial multitudes. Microbes can extract the fiber's extra energy, nutrients, vitamins and other compounds for us. Short-chain fatty acids obtained from fiber are of particular interest, as they have been linked to improved immune function, decreased inflammation and protection against obesity.

Today's Western diet, however, is exceedingly fiber-poor by historical standards. It contains roughly 15 grams of fiber daily, Sonnenburg noted. For most of our early history as hunter-gatherers, we were likely eating close to 10 times that amount of fiber each day. "Imagine the effect that has on our microbiota over the course of our evolution," he said.

Not all helpful fiber, however, needs to come from the roots and roughage for which our ancestors foraged, new research suggests. Kelly Swanson, a professor of comparative nutrition at the University of Illinois at Urbana-Champaign, and his team found that simply adding a fiber-enriched snack bar to subjects' daily diets could swing microbial profiles in a matter of weeks... The findings were published in the January issue of the American Journal of Clinical Nutrition.

As gut microbes are starved of fermentable fiber, some do die off. Others, however, are able to switch to another food source in the gut: the mucus lining that helps keep the gut wall intact and free from infection. In a recent study presented at the Keystone meeting, Eric Martens of the University of Michigan Medical School, postdoctoral researcher Mahesh Desai and their colleagues found that this fuel switch had striking consequences in rodents. A group of mice fed a high-fiber diet had healthy gut lining, but for mice on a fiber-free diet, "the mucus layer becomes dramatically diminished," he explained at the meeting. This shift might sometimes have severe health consequences. Research by a Swedish team, published last year in the journal Gut, showed a link between bacteria penetrating the mucus layer and ulcerative colitis, a painful chronic bowel disease.

A third group of mice received high-fiber chow and fiber-free chow on alternating days—"like what we would do if we were being bad and eating McDonald's one day and eating our whole grains the next," Martens joked. Even the part-time high-fiber diet was not enough to keep guts healthy: these mice had a mucus layer about half the thickness of mice on the consistently high-fiber diet. If we can extend these results to humans, he said, it "tells us that even eating your whole fiber foods every other day is still not enough to protect you. You need to eat a high-fiber diet every day to keep a healthy gut." Along the same lines, Swanson's group found that the gut microbiomes of his adult subjects reverted back to initial profiles as soon as the high-fiber bars were discontinued.