Several studies reveal some of the health benefits of fiber. The conclusion is to increase dietary fiber and decrease disease as long as you eat the correct amount of fiber you need for your health, since men and women have different dietary fiber needs. Men need about 38 grams of fiber daily, but women only need about 25 grams of fiber daily to manage their weight.
In one study from the Rain Forest Research Institute published in Inderscience Publishers, researchers found that adolescents who don't eat enough fiber tend to have bigger bellies and higher levels of inflammatory factors in their blood, both major risk factors for cardiovascular disease and diabetes.
Numerous studies have been done on the health benefits of fiber. Also see the news releases, "Fiber intake associated with reduced risk of death," and "Diets high in fiber won't protect against diverticulosis."
One review confirms benefits of more roughage in the diet. We should all be eating more dietary fiber to improve our health - that's the message from a health review by scientists in India. The team has looked at research conducted into dietary fiber during the last few decades across the globe and now suggests that to avoid initial problems, such as intestinal gas and loose stool, it is best to increase intake gradually and to spread high-fiber foods out throughout the day, at meals and snacks. Also check out the article, "Load up on fiber now, avoid heart disease later."
Writing in the International Journal of Food Safety, Nutrition and Public Health, the team offers fruit, vegetables, whole-grain foods, such as muesli and porridge, beans and pulses, as readily available foods rich in dietary fiber. You also can read the abstract of the original study, "Dietary fiber and human health" in the International Journal of Food Safety, Nutrition and Public Health, 2011, 4, 101-118. Also see, Dietary fiber and human health - School of Pharmacy.
Fiber boosts the immune system
You may want to see the article, " Dietary Fiber and Availability of Nutrients: A Case Study." And check out the study, An apple a day? Study shows soluble fiber boosts immune system. Researchers discuss the benefits of soluble fiber found in oats and apples, for example. The apples and oats study shows soluble fiber boosts immune system.
Dietary fiber, also known as roughage, is the general term of the non-digestible parts of the fruit and vegetable products we eat. There are two forms soluble and insoluble. Soluble (prebiotic, viscous) fiber that is readily broken down or fermented in the colon into physiologically active byproducts and gases. The second form is insoluble fiber, which is metabolically inert, but absorbs water as it passes through the digestive system, providing bulk for the intestinal muscles to work against and easing defecation.
Vikas Rana of the Rain Forest Research Institute, in Assam, India, and colleagues point out that research has shown that modern food habits have, it seems, led to an increase in the incidence of obesity, cardiovascular diseases, and type 2 diabetes. See, Dietary fiber and human health Vikas Rana* Rakesh - InderScience.
These are growing more common even in developing nations where a "western" diet of highly processed foods, high in sugars and saturated fats, beef and dairy products and low in dietary fiber is displacing more traditional options. The team suggests that evidence points to a loss of dietary fiber in the diet as being a major risk factor for health problems but one of the simplest to remedy without recourse to major changes in diet or the addition of supplements or so-called functional foods and nutraceuticals to the diet.
Given that dietary fiber has physiological actions such as reducing cholesterol and attenuating blood glucose, maintaining gastrointestinal health, and positively affecting calcium bioavailability and immune function, it is important for the current generation and future generations that this component of our diets be reasserted through education and information.
"Consuming adequate quantities of dietary fiber (DF) can lead to improvements in gastrointestinal health, and reduction in susceptibility to diseases such as diverticular disease, heart disease, colon cancer, and diabetes. Increased consumption has also been associated with increased satiety and weight loss," the team concludes, according to the November 10, 2011 news release, More fiber, but not necessarily less fat, good for teen diets. But regarding diverticular disease, check out the news release, "Diets high in fiber won't protect against diverticulosis."
Given the ready availability particularly in the West and in the relatively richer parts of the developing world of vegetables, fruit and other foods high in dietary fiber it is a matter of recommending that people eat more dietary fiber rather than consistently taking the unhealthy low-fiber option throughout their lives.
In another study, researchers found that gut bacteria supports gastrointestinal health
A July 2012 University of Illinois College of Agricultural, Consumer and Environmental Sciences study shows that dietary fiber promotes a shift in the gut toward different types of beneficial bacteria. And the microbes that live in the gut, scientists now believe, can support a healthy gastrointestinal tract as well as affect our susceptibility to conditions as varied as type 2 diabetes, obesity, inflammatory bowel disease, colon cancer, and autoimmune disorders such as rheumatoid arthritis.
As these microbes ferment fiber in the intestine, short-chain fatty acids and other metabolites are produced, resulting in many health benefits for the host, said Kelly Swanson, a U of I professor of animal sciences. "When we understand what kinds of fiber best nurture these health-promoting bacteria, we should be able to modify imbalances to support and improve gastrointestinal health," he explained in the news release, "Dietary fiber alters gut bacteria, supports gastrointestinal health."
Laxation is helping food move through the intestines
This research suggests that fiber is good for more than laxation, which means helping food move through the intestines, he added. Check out the abstract of the original study, in the July 2012 issue of the Journal of Nutrition. Also, regarding another study on fiber, see the site, Increase dietary fiber, decrease disease.
"Unfortunately, people eat only about half of the 30 to 35 grams of daily fiber that is recommended. To achieve these health benefits, consumers should read nutrition labels and choose foods that have high fiber content," said Swanson in the news release. In the placebo-controlled, double-blind intervention study, 20 healthy men with an average fiber intake of 14 grams a day were given snack bars to supplement their diet. The control group received bars that contained no fiber; a second group ate bars that contained 21 grams of polydextrose, which is a common fiber food additive; and a third group received bars with 21 grams of soluble corn fiber.
On days 16-21, fecal samples were collected from the participants, and researchers used the microbial DNA they obtained to identify which bacteria were present. DNA was then subjected to 454 pyrosequencing, a "fingerprinting" technique that provides a snapshot of all the bacterial types present.
What food makes the beneficial probiotics increase in the gut
Both types of fiber affected the abundance of bacteria at the phyla, genus, and species level. When soluble corn fiber was consumed, Lactobacillus, often used as a probiotic for its beneficial effects on the gut, increased. Fecalibacterium populations rose in the groups consuming both types of fiber.
According to Swanson, the shifts in bacteria seen in this study—which occurred when more and differing types of fiber were consumed—were the opposite of what you would find in a person who has poor gastrointestinal health. That leads him to believe that there are new possibilities for using pre- and probiotics to promote intestinal health.
"For example, one type of bacteria that thrived as a result of the types of fiber fed in this study is inherently anti-inflammatory, and their growth could be stimulated by using prebiotics, foods that promote the bacteria's growth, or probiotics, foods that contain the live microorganism," he said.
The original study appeared in the July 2012 issue of the Journal of Nutrition. . Co-authors are Seema Hooda, Brittany M. Vester Boler, Mariana C. Rossoni Serao, and George C. Fahey Jr., all of the U of I Department of Animal Sciences; Jennifer M. Brulc, Michael A. Staeger, and Thomas W. Boileau, all of the General Mills, Inc., Bell Institute of Health and Nutrition; and Scot E. Dowd of MR DNA Molecular Research LP, Shallowater, TX. Funding was provided in part by General Mills.
Low-fiber diet puts teenagers at a higher risk of getting cardiovascular disease
Adolescents who don't eat enough fiber tend to have bigger bellies and higher levels of inflammatory factors in their blood, both major risk factors for cardiovascular disease and diabetes, researchers report in a 2012 study. The research looked at 559 adolescents age 14-18 from Augusta, Georgia.
The study revealed that they consumed on average about one-third of the daily recommended amount of fiber, said Dr. Norman Pollock, bone biologist at the Medical College of Georgia and the Institute of Public and Preventive Health at Georgia Health Sciences University in a June 1, 2012 news release, "Low-fiber diet puts adolescents at higher risk of cardiovascular disease."
"The simple message is adolescents need to eat more fruits, vegetables and whole grains," Pollock said in the news release. "We need to push recommendations to increase fiber intake." He and Dr. Samip Parikh, an internal medicine resident at GHS Health System, are co-first authors of the study in the Journal of Clinical Endocrinology and Metabolism. Only about 1 percent of the young participants consumed the recommended daily intake of 28 grams for females and 38 grams for males. The study appears the first to correlate dietary fiber intake with inflammatory markers in adolescents.
Better understanding the relationships and risks of diet, inactivity and obesity in children and adolescents is particularly critical at a time when about 1 in 3 is overweight or obese, Parikh said. That's nearly triple the rate since 1963, according to the American Heart Association. Also see the news release, "Soluble fiber strikes a blow to belly fat."
Low-fiber consumers in the study were more likely to have more of the visceral fat found in and around major organs in their abdominal cavity
They also tended to have higher levels of inflammatory factors, such as immune cells called cytokines, as well as lower levels of protective adiponectin, a protein secreted by fat that helps the body use glucose and fight inflammation. Interestingly, adiponectin levels tend to drop when fat becomes excessive and obesity is generally considered a chronic inflammatory state.
Exactly how fiber helps stave off some of these unhealthy consequences is not completely clear, Parikh said. in the news release. Hypotheses include increased bulk in the stool causing digested food to spend less time in the gastrointestinal tract and the ability of fiber to improve insulin sensitivity, potentially reducing visceral adiposity. More indirectly, fiber tends to speed satiety, potentially decreasing total food and caloric consumption, Parikh said. It may also help absorb and eliminate inflammatory factors.
Belly fat and inflammatory factors
While belly fat and high inflammatory factors are inexorably linked to bad consequences such as heart disease and often occur together, one did not directly cause the other in this instance, Pollock explained according to the news release. He was co-first author earlier this year of a study on the same group of adolescents that showed high-fructose consumption correlated with higher blood pressure, fasting glucose, insulin resistance and inflammatory factors as well as lower levels of cardiovascular protectors such as such as HDL cholesterol and adiponectin.
These dangerous associations were exacerbated by belly fat. "There is some other mechanism (for increased inflammatory factors associated with low-fiber intake)," Pollock noted. The scientists acknowledge getting adolescents to eat more fiber can be tough, not only because of their penchant for processed foods but because side effects can include intestinal gas, bloating and diarrhea. They are pursuing funding to develop more palatable forms of fiber that could be sprinkled, for example, on the low-fiber foods most adolescents regularly consume.
Study participants were part of a larger study assessing the relationship between activity and diet. The scientists noted that low-fiber intake also was linked to higher levels of overall body fat but only in females. A high-fiber diet seemed to reduce general body fat in males.
More fiber, but not necessarily less fat, good for teen diets
A study published on November 11, 2010 from Michigan State University focuses research that emphasize diets that include fiber-rich, nutrient-dense plant-based foods. A diet high in fiber – but not necessarily one low in saturated fat or cholesterol – is tied to a lower risk of heart disease and type-2 diabetes in teenagers, according to new findings from Michigan State University.
A study led by Joseph Carlson of MSU's Division of Sports and Cardiovascular Nutrition suggests to reduce metabolic syndrome – a collection of risk factors including high blood pressure and a large waistline – it is more important to emphasize diets including fiber-rich, nutrient-dense, plant-based foods than focus on restricting foods high in cholesterol or saturated fat. The research is published in Journal of the American Dietetic Association.
"What we found is that as fiber intake increases, the risk for metabolic syndrome decreases," said Carlson, a registered dietitian and associate professor at MSU, according to November 11, 2010 news release, More fiber, but not necessarily less fat, good for teen diets. "High-fiber, nutrient-dense foods are packed with heart healthy vitamins, minerals and chemicals that can positively affect many cardiovascular risk factors.
"It may be better to focus on including these foods than to focus, as is commonly done, on excluding foods high in saturated fat." That doesn't mean, however, that teens should have carte blanche in eating foods high in saturated fat and cholesterol, Carlson said in the news release. "It is well established that saturated fat can raise bad cholesterol," he said. "What this data suggest is the importance of including foods high in dietary fiber."
Processed foods availability and from where some of a teenager's dietary intake comes
With the high availability of processed foods today, Carlson said, it is possible for teens to eat a diet that is low in saturated fat and cholesterol but that also is low in fiber and nutrient-rich, plant-based foods. Recent national data indicates up to 30 percent of teens' dietary intake comes from beverages and sugar-rich snacks.
Due to low intakes of fruits, vegetables, whole grains and beans, the total dietary fiber intake in teens is about 13 grams per day, well below the recommendation of 26 grams and 38 grams for female and male adolescents, respectively. In addition, obesity and other key risk factors associated with metabolic syndrome are on the rise in youth.
More than 70 percent of teens in the study had at least one of the five risk factors used to assess metabolic syndrome: high blood pressure, high levels of sugar and fat in the blood, low levels of good cholesterol and a large waistline (a person having three or more of the factors are classified as having the syndrome). Also see the news releases, "Grain fiber and magnesium intake associated with lower risk for diabetes," and "Diabetics on high-fiber diets might need extra calcium, report UT Southwestern researchers."
"One of the takeaways is that our study reinforced the current dietary recommendations for dietary fiber intake by including a variety of plant-based foods," Carlson explained in the news release. "A strategy of emphasizing fiber-rich foods may improve adherence to dietary recommendations."
Boosting dietary fiber intakes to levels that will improve or sustain a desirable cardiovascular risk factor status
The next step, he said, is to figure out the best methods to boost dietary fiber intakes to levels that will improve or sustain a desirable cardiovascular risk factor status. For example, if a person daily has three servings of fruit and vegetables (12 grams of fiber), one serving of beans (seven grams), and three servings of whole grain, they will be at about 30 grams of dietary fiber. "The trick is getting people in the groove finding the foods that they both enjoy and are convenient," Carlson said in the news release.
As part of the cross-sectional study, Carlson and his team focused on data collected as part of the National Health and Nutrition Examination Survey done from 1999-2002. They analyzed the diets of more than 2,100 boys and girls ages 12 to 19, looking at whether the teens had three or more conditions that make up metabolic syndrome.
The study found there was a three-fold increase in the number of children that had metabolic syndrome when the group of children receiving the least fiber was compared with the group receiving the most. There was not a significant relationship with either saturated fat or cholesterol intake.
Michigan State University has been working to advance the common good in uncommon ways for more than 150 years. One of the top research universities in the world, MSU focuses its vast resources on creating solutions to some of the world's most pressing challenges, while providing life-changing opportunities to a diverse and inclusive academic community through more than 200 programs of study in 17 degree-granting colleges.