Which Source of Dietary Fiber Works Best?

Amy Norton wrote . . . . . . . . .

If your diet is low in fiber, you can do your gut some good by adding more — regardless of the fiber source, new research suggests.

Many people know fiber as the nutrient that keeps you regular. But it’s also a key player in the makeup of the gut microbiome — the vast collection of bacteria and other microbes that reside in the digestive tract.

When bacteria in the gut break down the fiber, they produce certain short-chain fatty acids that are the main source of nutrition for cells in the colon. Research also suggests the fatty acids play a role in regulating functions as vital as metabolism and immune defenses.

But it hasn’t been clear whether any one type of fiber supplement is better for people’s gut bacteria than others.

In the new study, researchers tested three common fiber-powder supplements: inulin (an extract of chicory root), wheat dextrin (in this case, the brand Benefiber), and galactooligosaccharides (Bimuno).

They recruited 28 healthy adults and gave them each of the supplements to use for one week, with one week off in between each product.

Overall, the study found, no one supplement outperformed the others in changing consumers’ gut microbiome. Each supplement boosted the production of butyrate — an important fatty acid that helps control inflammation.

If a study participant churned out more butyrate after using one fiber supplement, they responded just as well to the other two, said Jeffrey Letourneau, a doctoral student at Duke University in Durham, N.C., who was part of the research team.

But while the fiber supplement didn’t matter, the person did: Supplements revved up butyrate production only in participants who normally ate few fiber-rich foods, the study found.

That does make sense, according to Letourneau: It’s the “low fiber consumers” who would be making a substantial change by adding a daily fiber supplement.

But that term also describes most Americans, he pointed out.

Experts generally recommend that women strive for 25 grams of fiber per day, while men should aim for 38 grams. The average U.S. adult, however, consumes only in the neighborhood of 30% of those amounts.

And in the grand scheme of human history, Letourneau said, even the recommended fiber amounts probably fall far short of what our ancestors downed. He pointed to research showing that members of the Hadza tribe, in Tanzania, still consume a whopping 100 to 150 grams of fiber a day — owing to diets high in foods like berries, honey and tubers.

So the new research — published in the journal Microbiome — emphasizes the importance of getting more fiber, whatever the source.

The study focused on supplements, in part, because they are easy to study, Letourneau said. Researchers gave each participant pre-measured individual doses of the fiber supplements, so they simply had to dump the powder into a drink once a day.

Those doses amounted to 9 grams of either inulin or wheat dextrin, or 3.6 grams of galactooligosaccharides, per day.

Fiber from food, however, would be preferable, according to a registered dietitian who was not involved in the study.

Plant foods provide not only various forms of fiber, but also a range of vitamins, minerals and beneficial “phytochemicals,” said Nancy Farrell Allen, a spokeswoman for the Academy of Nutrition and Dietetics and an instructor at Rosalind Franklin University of Medicine and Science in North Chicago, Ill.

“I believe that food is the best way to meet fiber needs,” she said.

Farrell Allen pointed to a long list of fiber-rich foods, including an array of vegetables and fruit; bran cereals and whole grains like farro; “pulses” such as lentils and chickpeas, and legumes like soybeans and peanuts.

She also had a caution on fiber supplements: They can cause unpleasant gas, bloating and prolonged indigestion.

Letourneau agreed that whole foods have “real benefits” that cannot be captured in a supplement. But given the importance of fiber — and the dearth of it in Americans’ diets — he supports getting more of it, however you can.

“My attitude is: Whatever you can fit into your life, in a sustainable way, is good,” Letourneau said.

In some more good news, it doesn’t take long for any added fiber to make a difference to your gut bacteria. In a separate study, the Duke researchers found that fiber supplements began to alter people’s gut bacteria within a day — changing the microbiome makeup and activity.

“Things do seem to change really quickly,” Letourneau said.

Source: HealthDay





Large Study: Vitamin D Supplements Won’t Help Your Bones

Dennis Thompson wrote . . . . . . . . .

Seniors who take vitamin D supplements to improve their bone health and ward off fractures are just wasting their time and money, a major new study has found.

These supplements did nothing to reduce their average risk of bone fractures, researchers found in a randomized trial testing vitamin D against a placebo.

“In generally healthy adults, these results do not support the use of vitamin D supplements to reduce fracture risk,” said lead researcher Dr. Meryl LeBoff, chief of the Calcium and Bone Section at Brigham and Women’s Hospital in Boston. “We found that supplemental vitamin D did not reduce fractures in U.S. participants.”

In the study, published in the New England Journal of Medicine, more than 25,000 older adults were randomly assigned to take either 2,000 units of vitamin D daily or a placebo, and then followed for an average of five years. The average age of participants was 67.

Nearly 2,000 bone fractures occurred among more than 1,500 participants during the study period. However, taking vitamin D appears to have had no bearing on who suffered a fracture and who didn’t.

Nearly 20% of U.S. adults currently take vitamin D supplements, researchers said in background notes, often based on blood tests that find they have “insufficient” or “deficient” levels of vitamin D.

These new results should cause both doctors and patients to question the value of routine vitamin D testing, said Dr. Steven Cummings, a professor emeritus at the University of California, San Francisco.

“Doctors routinely order vitamin D levels, and many patients hear that they are low, they’re below some level,” said Cummings, co-author of an editorial accompanying the findings. “What we needed to know is whether those people who have low levels benefit from taking vitamin D. And the answer to that is no.”

The clinical trial could shake the vitamin D market, which is worth more than $1 billion globally according to market watchers.

Vitamin D had been thought to help improve bone health because it is essential to your body’s absorption of calcium, LeBoff said.

“Mechanistically, vitamin D may support bone health and improve mineralization of bone because it increases the absorption of calcium, and 99% of calcium is stored in bone,” LeBoff said, adding that studies had also shown that the vitamin could affect bone turnover and bone formation.

In addition, some bone diseases such as rickets have been linked to a severe vitamin D deficiency in people, Cummings noted.

Most people get enough vitamin D naturally via their skin, which produces it when exposed to sunlight, LeBoff said.

It’s also found in vitamin D-supplemented milk, eggs and cereal, as well in fish like salmon, trout and tuna, she said.

Cummings believes there’s a fundamental misunderstanding of vitamin D that’s likely driving all this testing for vitamin D deficiency.

His editorial noted that more than 10 million blood tests for vitamin D levels are performed every year in the United States.

“There’s a system in your body that’s kept in balance by vitamin D that you take in, the vitamin D from your skin and the enzymes that turn it into an active form of vitamin D called D125. That system is kept in balance naturally by your body,” Cummings said.

“I think what we’re learning is that vitamin D is not a vitamin, it’s a hormone, and it’s hard to perturb that balance, to change that balance in a beneficial way,” he said.

LeBoff noted that this study did not include people with osteoporosis, a genetically driven vitamin D deficiency, or very elderly people living in residential communities.

For people in these groups, supplemental vitamin D could be helpful or essential in maintaining their bone health.

“Don’t stop your grandfather’s vitamin D, because these findings really are found in mid-life and older adults,” LeBoff said.

Source: HealthDay





Expert Panel: Vitamins, Supplements Useless for Most People

Denise Mann wrote . . . . . . . . .

Millions of people pop vitamins and supplements every day in hopes of staving off heart disease and cancer, but a new report finds the evidence to support that strategy is largely lacking.

While there is some research showing that a daily multivitamin may slightly reduce cancer risk, the bigger picture suggests a lack of enough evidence to say that supplements can help prevent heart disease and cancer.

There is, however, enough evidence to state that beta carotene supplements may actually increase risk of lung cancer, especially among folks who are at high risk, and may also increase the chances of dying from heart disease. What’s more, vitamin E provides no cancer or heart disease prevention benefits.

Those are the main takeaways from the new report from the U.S. Preventive Services Task Force, an independent panel of national experts that regularly make evidence-based recommendations about preventive health issues. This report updates the group’s 2014 stance on this topic.

“This is not a negative message, and it isn’t saying that there are no [cancer or heart disease prevention benefit] for vitamins and minerals,” cautioned task force vice chair Dr. Michael Barry. He’s the director of the Informed Medical Decisions Program in the Health Decision Sciences Center at Massachusetts General Hospital, in Boston.

“We called for more research with longer follow-up, as well as studies across different racial and ethnic groups, to see if there are variations,” Barry added.

The recommendations are based on a review of 84 studies on multivitamins, supplement pairs or individual supplements, and cardiovascular disease and cancer risk in healthy, non-pregnant adults, published between January 2013 and February 2022.

“For the most part, vitamin and mineral supplementation did not reduce cancer or heart disease [risk],” said Elizabeth O’Connor. She is an associate director at Kaiser Permanente Evidence-Based Practice Center in Portland, Ore. O’Connor is one of the researchers who helped analyze the studies included in the new recommendations.

Research did show a 7% reduction in cancer risk among people taking a multivitamin, compared to those taking a dummy pill or placebo. Still, the studies that led to this conclusion had limitations, including short follow-up. “Even though this finding was statistically significant, there are some lingering questions,” O’Connor said.

Importantly, the new recommendations do not apply to people with known or suspected nutritional deficiencies or special needs, such as people who are or may become pregnant and need folic acid.

The recommendations were published online in the Journal of the American Medical Association.

“Vitamin and mineral supplements are not a silver bullet for healthy Americans,” said Dr. Jenny Jia, who wrote an editorial accompanying the new study. She is an instructor of general internal medicine at Northwestern University’s Feinberg School of Medicine, in Chicago.

Instead of popping vitamins, focus on eating a balanced diet that is loaded with fruits and vegetables, exercising regularly, and getting the recommended screening tests to help prevent heart disease and cancer, she said. “Vitamins and minerals are a distraction, and offer minimal to no benefit for healthy American adults,”Jia noted.

Dr. Mark Moyad is the Jenkins/Pokempner director of preventive & alternative medicine at the University of Michigan Medical Center in Ann Arbor. He sees things differently, especially when it comes to daily multivitamins. “They may reduce cancer, and even though it’s a modest reduction, this is not a small deal,” said Moyad, who had no ties to the research.

“It’s not so much of a Wild West out there anymore when it comes to supplements,” he added. Many third-party groups now offer seals of approval for brands that are quality tested and contain what the label says they do.

“If you do take supplements, seek out ones that have a clean track record,” Moyad suggested.

The Council for Responsible Nutrition, which represents the supplements industry, took issue with the new report.

“Americans fall short in many key nutrients,” Andrea Wong, the organization’s Senior Vice President of Scientific and Regulatory Affairs, said in a statement. “In fact, the Food and Drug Administration and the 2020–2025 Dietary Guidelines for Americans identified that under-consumption of calcium, potassium, dietary fiber, and vitamin D is of public health concern for the general U.S. population because low intakes are associated with numerous health concerns.”

Wong pointed to evidence from the recent Cocoa Supplement and Multivitamin Outcomes Study (COSMOS), which she said suggests that “multivitamins help delay cognitive decline in older people.” Wong also cited data from the ongoing Physicians’ Health Study II, a “controlled trial [that] showed an 8% reduction in overall cancer risk in older male physicians who took a multivitamin.”

Source: HealthDay


Vitamin D Supplements Won’t Help Prevent Diabetes

While vitamin D may have other benefits, preventing type 2 diabetes in high-risk adults does not appear to be one of them.

A new Japanese trial found no significant difference among study participants who used a vitamin supplement and those who took a placebo.

“Although treatment with eldecalcitol [an active form of vitamin D used to treat osteoporosis in Japan] did not significantly reduce the incidence of diabetes among people with prediabetes, the results suggested the potential for a beneficial effect of eldecalcitol on people with insufficient insulin secretion,” the researchers said.

For the study, Tetsuya Kawahara from the University of Occupational and Environmental Health in Kitakyushu, Japan, and colleagues assessed whether eldecalcitol could reduce type 2 diabetes risk in 630 individuals with impaired glucose tolerance. They were compared to 626 participants who received a placebo.

The individuals were recruited from three hospitals in Japan between 2013 and 2019. With an average age of 61, about 46% were women and 59% had a family history of type 2 diabetes. They were tested for diabetes every three months over three years.

The upshot: Researchers found no meaningful differences between the groups.

About 12.5% of the eldecalcitol group developed diabetes compared to 14% of the placebo group. Blood sugar levels returned to normal in about 23% of the eldecalcitol group and 20% of the others, the findings showed.

The report was published online in the BMJ.

After adjusting for other influential factors, the investigators did find that eldecalcitol may prevent type 2 diabetes in some prediabetic patients. The finding is unclear and more research is needed, the study authors noted in a journal news release.

The study also found a significant increase in both lower back and hip bone mineral densities in individuals who took vitamin D.

Not clear is whether the dose the team chose was the appropriate one for preventing diabetes or whether the results could be applied to all ethnic groups.

About 480 million people worldwide have type 2 diabetes, and the number is expected to reach 700 million by 2045. About a half-billion people have impaired glucose tolerance or prediabetes.

While weight loss and exercise can reduce type 2 diabetes risk, they are hard to sustain, prompting a search for new strategies.

In an accompanying journal editorial, Dr. Tatiana Christides of Queen Mary University of London noted that several questions remain. They include whether vitamin D supplementation may be more effective for particular populations, and whether longer treatment or starting at a younger age might be beneficial.

Health care professionals “should continue to discuss with patients the musculoskeletal health benefits of vitamin D and support them to achieve and maintain lifestyle changes that, although challenging to sustain, are known to decrease development of type 2 diabetes,” Christides said.

Source: HealthDay

Calcium Supplements Could Spell Trouble for Older Heart Patients

Dennis Thompson wrote . . . . . . . . .

Seniors are often advised to take calcium supplements, but new research says the pills might significantly increase an aging person’s risk of heart valve problems that contribute to heart failure.

People taking either calcium supplements alone or calcium with vitamin D had a higher risk of heart-related death or death from any cause compared with people not taking supplements, the researchers reported.

These folks also were more likely to need surgery to replace their aortic valve.

For example, results showed that people taking calcium plus vitamin D had a doubled risk of heart-related death, while those taking calcium alone were nearly three times as likely to need surgery to replace their heart valve.

“Taking additional calcium cannot be helpful, and may be even harmful,” said senior researcher Dr. Samir Kapadia, chair of cardiovascular medicine with the Cleveland Clinic, in Ohio. “If you are taking additional calcium, you want to analyze your situation with an expert to assess whether it’s absolutely necessary.”

Aortic stenosis occurs when the aortic valve — the main outflow valve of the heart — stiffens or narrows, blocking blood flow from the heart out to the rest of the body.

“Normally, the valve opens to the size of a quarter,” Kapadia said. “In about 5% of people more than 75 years of age, the valve gets calcified. Accumulation of calcium happens, so that the valve is not opening as wide as it normally should,” he explained.

“When the valve opens less than the size of a dime, it is considered very critical and it is a risk for developing heart failure or death,” Kapadia said.

Calcium supplements have been suspected as a contributor to aortic stenosis, since calcium meant for the bones can just as easily migrate to heart valves, the researchers said in background notes.

But until now, research into calcium and heart valve problems has mainly taken place in animals. At the same time, the prescription of calcium with vitamin D has risen sharply in recent years, particularly among postmenopausal women, the investigators noted.

To see whether calcium might contribute to heart valve problems, Kapadia and his colleagues tracked the heart health of over 2,600 patients who already had mild to moderate calcification of their aortic valve.

The patients’ average age was 74, and they were tracked more than 5.5 years on average. Patients were divided into those taking calcium, those taking calcium plus vitamin D, and those not taking any supplements.

The study found that people taking calcium with vitamin D had an absolute risk of heart-related death of 13.7 deaths per 1,000 person-years, compared with 5.8 deaths per 1,000 person-years in people not taking any supplements. (Person-years is the product of number of years times number of members of a population who have been affected by a certain condition.)

Supplemental calcium plus vitamin D increased risk of death from any cause by 31%, while calcium alone was linked to a 24% higher risk of all-cause mortality, the study found.

The results were published online in the BMJ.

Dr. Matthew Tomey, a cardiologist with Mount Sinai Morningside in New York City, noted that the development of aortic stenosis closely resembles the way bone normally forms.

Because of that, “the concept of calcium supplementation as a modifier of aortic stenosis disease progression is interesting,” said Tomey, who wasn’t involved in the study.

However, he cautioned that since this is an observational study, it cannot establish a clear cause-and-effect link between calcium supplements and heart valve problems.

“The findings of the study are nonetheless hypothesis-generating and underscore the need for a randomized study of benefits and risks of commonly used supplements for cardiovascular health,” Tomey said.

“We would do well to remember that ‘more’ is not always ‘more’ — supplements can be double-edged swords,” Tomey concluded.

Kapadia said that aging people would be better off getting their recommended calcium through their diet, and should talk to their doctor about their bone health concerns.

He noted that vitamin D — which your body requires for bone to absorb calcium — by itself did not cause any heart health problems among the patients in his study. And there’s evidence that another supplement, vitamin K2, can “help the calcium go to the bone rather than the heart,” Kapadia added.

People diagnosed with bone-thinning osteoporosis also have many other medications available to them outside of calcium supplements, Kapadia said. These include bisphosphonates, hormone therapy and bone-building drugs.

Dr. S. Allen Luis, an associate professor of medicine at the Mayo Clinic in Rochester, Minn., isn’t rushing to judgment based on these study results. Besides calcium supplements, “there can also be a number of other factors — including diet, other medication use or medical problems that the person has — that also exist which may not have been taken into account,” Luis said.

Also, a number of other studies have not shown associations between calcium supplement use and heart disease. “While these findings are very interesting, I think that this needs to be explored further,” he added.

If someone has osteoporosis, Luis advised looking at the risks for the person as a whole. “In this case, we need to balance against potential risks of broken bones or fractures related to osteoporosis. These are very important to prevent due to the significant impact that they have on people’s life,” he said.

Source: HealthDay