Why Fiber Matters?

A recent review article (J O’Grady et al. Aliment Phamacol Ther; 2019; 49: 506-15) highlights how fiber is important for health and its potential role in fostering a diverse microbiome. Some of the material has been covered before in a previous blog/presentation: It’s Alimentary!  “The Fiber Movement: Why Kids Need It and How to Get It” by Maria Oliva-Hemker .

In the introduction, the authors note that there had been a period of disappointment that fiber did not seem to help irritable bowel syndrome.  Though with expanding knowledge of the diet-, microbiome- host interactions, clinicians have started to appreciate the health impact of dietary fiber.

In subsequent sections, the authors detail the different types of fiber based on solubility, viscosity and fermentation.

Key actions of fiber:

  • Anti-inflammatory effects
  • Immune system modulation
  • Regulation of cell proliferation and differentiation
  • Richer microbiome diversity (may lower risk of C difficile)

The authors note that a low-fiber diet in germ-free mice can result in a reduced microbial diversity and interestingly, the “missing taxa is transmitted to subsequent generations” even if fiber is re-introduced.

Potential beneficial fiber effects beyond bulking up stools:

  • Reduced adiposity
  • Lower metabolic disease including lower cholesterol and better glucose metabolism
  • Lower incidence of chronic inflammatory diseases
  • “Potential for fiber to prevent… diverticular and neoplastic disorders”

Western Diet is Deficient in Fiber.

  • Recommendations for fiber intake of 14 g per 1000 kcal consumed, which equates to approximately 25 g for females and 38 g for males (depending on energy intake).
  • In underdeveloped countries and historically, intakes are more than 50 g (in Africa) and up to 100 g/day in ancestral humans
  • Actual intake in U.S. is only 12-18 g/day.

The authors recommend efforts to gradually titrate increased fiber in the diet as abrupt changes may be poorly tolerated due to gas and bloating.

My take: This article explains that the connection between fiber intake and a number of health outcomes is likely due, at least in part, to its modulation of the microbiome. Thus, fiber is important for much more than a good poop.

Related blog posts:

It’s Alimentary (Part 1)

A recent ‘clinical quality forum’ sponsored by The Children’s Care Network (TCCN) and Nutrition4Kids featured several good lectures. The symposium was titled, “It’s Alimentary.”  What follows are my notes –the full lectures from these talks will be available in the coming weeks on the Nutrition4Kids website. My notes may include some errors in transcription and errors of omission.

The Fiber Movement: Why Kids Need It and How to Get It” by Maria Oliva-Hemker (Director of Division of Pediatric Gastroenterology, Johns Hopkins). This was a terrific lecture which pulled together a lot of useful information.   Despite hearing a lot about fiber, this lecture showed me that there is a lot that I still need to learn.

Key points:

  • Institute of Medicine recommends 14 grams of fiber per 1000 kcal of dietary intake.  This is a higher amount of fiber than prior recommendations.
  • Most adults are consuming about 50% of the fiber that they should
  • Whole foods should be encouraged over fiber supplements
  • Increased fiber associated with lower risk of obesity, stroke, coronary heart disease, and diabetes

Related blog posts:

The LEAP Study and Its Implication for the Future of Food Allergies” Kiran Patel (Professor Pediatrics, Division of Allergy and Immunology, Emory University)  This was the second opportunity that I had to hear Dr. Patel in the past 6 months –see An Allergy-Immunology Perspective on GI Diseases

Key points:

  • There has been an increasing incidence of peanut allergies
  • Early introduction of peanuts helps reduce peanut allergies. Suggested algorithm
  • To reduce allergies, placing a best practice alert in electronic record could be necessary as rates of encouraging early peanut introduction in at risk children remains low

Related blog posts:

 

LEAP study results

Slides with information on introduction of peanuts –this should be discussed with physician before implementation.

Disclaimer: These blog posts are for educational purposes only. Specific dosing of medications/diets (along with potential adverse effects) should be confirmed by prescribing physician/nutritionist.  This content is not a substitute for medical advice, diagnosis or treatment provided by a qualified healthcare provider. Always seek the advice of your physician or other qualified health provider with any questions you may have regarding a condition.

Why Fiber (Fruits and Veggies) is Good for You

A recent NY Times piece provides a summary of recent studies in mice which show that a low fiber diet promotes inflammation throughout the body and results in changes in the microbiome: Fiber is Good For You. Now Scientists May Know Why

An excerpt:

A diet of fiber-rich foods, such as fruits and vegetables, reduces the risk of developing diabetesheart disease and arthritis. Indeed, the evidence for fiber’s benefits extends beyond any particular ailment: Eating more fiber seems to lower people’s mortality rate, whatever the cause…

The ability of these bacteria to survive on fiber we can’t digest ourselves has led many experts to wonder if the microbes are somehow involved in the benefits of the fruits-and-vegetables diet. Two detailed studies published recently in the journal Cell Host and Microbe provide compelling evidence that the answer is yes.

In one experiment, Andrew T. Gewirtz of Georgia State University and his colleagues put mice on a low-fiber, high-fat diet… the scientists were able to estimate the size of the gut bacterial population in each mouse. On a low-fiber diet, they found, the population crashed, shrinking tenfold.

Dr. Bäckhed and his colleagues carried out a similar experiment, surveying the microbiome in mice as they were switched from fiber-rich food to a low-fiber diet…Along with changes to the microbiome, both teams also observed rapid changes to the mice themselves. Their intestines got smaller, and its mucus layer thinner. As a result, bacteria wound up much closer to the intestinal wall, and that encroachment triggered an immune reaction…

“It points to the boring thing that we all know but no one does,” Dr. Bäckhed said. “If you eat more green veggies and less fries and sweets, you’ll probably be better off in the long term.”

Related blog posts:

Lower Fiber Intake May Increase Risk of Crohn’s Flare

According to a recent study, lower fiber intake was associated with an increased risk of a flare of Crohn’s disease over a 6-month period (CS Brotherton et al. Clin Gastroenterol Hepatol 2016; 1130-36).

This study examined dietary surveys from 1619 participants (Crohn’s disease in 1130, Ulcerative colitis in 489).  All participants were considered to be in remission at baseline. The key endpoint was disease flare at 6 months which was defined as a disease activity index score exceeding remission cutoff values.

Key finding: “Compared with those in the lowest quartile of fiber consumption, participants with Crohn’s disease in the highest quartile were less likely to have a flare” (adjusted odds ratio 0.58). There was no significant association with ulcerative colitis.

The associated editorial (1137-39) notes that “among 12 RCTs that enrolled patients with Crohn’s disease, fiber did not influence disease activity in studies of induction (flare to remission) or maintenance (remission to flare)…most RCTs had small sample size.”

My take (borrowed from editorial): “A high fiber diet is likely safe in patients with IBD [in the absence of a known stricture/obstructive symptoms] and may impart a weak benefit.”  Overall, dietary approaches are gaining traction and careful evaluation of competing claims will likely be of great benefit.

Related blog posts:

This is where I was completely soaked. Grinnell Trail

This is where (moments later) I was completely soaked. Grinnell Trail

Nutrition Support for Intestinal Failure

A recent blog post by Kipp Ellsworth (The Pediatric Nutritionist) highlights a recent lecture by Conrad Cole that provides several useful points.  The post includes a link (embedded talk) to 76 slides. Here are a few:

  • Iodine deficiency: Dr. Cole “typically orders a TSH level every six months, also ordering a spot urine iodine if a significant TSH uptrend emerges.”
  • Lipids: “Dr. Cole reviewed evidence revealing the restriction of soy-based lipids to 0.5 gm/kg/day as nearly efficacious as the use of fish-oil infusion (Omegaven) in preventing PNALD.” Daily use of 0.5-1 gm/kg/day is less error-prone than using lipids 3-4 times/week.
  • Formula: “breastmilk constitutes the touchstone of enteral nutrition choices for the intestinal rehab patient, conferring a host of benefits beyond those associated with formula alone… the medium-chain triglyceride component of many oligomeric and monomeric formulas constitutes a therapeutically valuable source of nutrition, increasing the proportion of calories absorbed.”
  • Formula for toddlers: “Dr. Cole continues transitioning his patients to oligomeric and monomeric formulas such as Elecare Junior, Pediasure Peptide, and Peptamen Junior upon reaching toddlerhood.”
  • Fiber: “Dr. Cole recommended the use of a sc-FOS product such as NutraFloraas optimal for the short bowel syndrome population.  Dr. Cole initially doses soluble fiber at 1 gm/100 mL of formula and advances as tolerated to a maximum of 2 gm/100 mL formula.  He typically does not use supplemental fiber to control ostomy output in patients without a colon in continuity”
  • Enteral fish oil: “Dr. Cole remains unconvinced of the therapeutic value of enteral fish oil supplementation pending further research studies on the subject.”

Funding for his talk was provided by Abbott Nutrition.

Related blog posts:

 

 

 

Dropping Weight by Adding Fiber in Diet

A recent study showed that increasing fiber in the diet helped participants lose weight.  The details are noted in this LA Times story: To lose weight, experts suggest a focus on fiber

Here’s an excerpt:

If you’re trying to lose weight, you could count your calories, keep track of precisely how much salt and sugar your eat, and make sure you hit certain targets for protein, carbohydrates, cholesterol and the various types of fat. Or you could set all of that aside and concentrate on just one thing: Eating at least 30 grams of fiber each day.

In a yearlong clinical trial involving 240 obese people who had metabolic syndrome, those who focused on fiber lost almost as much weight as those who followed the American Heart Assn.’s extremely detailed dietary recommendations.

Related blog posts:

Some funny headlines form Freakomomics website –here’s one:

Screen Shot 2015-02-22 at 9.35.46 AM

 

Green beans for short gut syndrome

A recent article indicates that the addition of green beans may improve diarrhea and reduce dependence on parenteral nutrition (Adding Dietary Green Beans to Formula Resolves the Diarrhea ) (ICAN. DOI: 10.1177/1941406412469403). Thanks to Kipp Ellsworth for pointing out this reference on his twitter feed.

This small retrospective study of 18 infants examined the addition of green beans to the diet of infants with short bowel syndrome (SBS) (1 jar of stage 2 baby food green beans to every 8 ounces of 30 cal formula).  The average gestational age of the patients was 32 weeks (range 23-39 weeks) and the average birth weight was 1938 gram.  Nine patients had NEC, four had gastroschisis, two had Christmas tree defect, and three had other reasons for either SBS or intestinal failure.  The IF group (n=10) was defined as being dependent on parenteral nutrition to meet nutritional needs; the SBS group (n=8), who were more severely affected, was defined as the malabsorptive state that follows a massive resection.

Products that were used:

  • Gerber Natural Select: 3 gm of fiber per 4 ounce
  • Beach-Nut Homestyle: 2 gm of fiber per 4 ounce
  • HyVee Mother Choice: 2 gm of fiber per 4 ounce
  • These products average 32% soluble and 68% insoluble fiber

While the authors note that they use only amino-acid based formulas currently, at the time of the study, 61% were receiving Peptamen Junior.

It is not clear in the manuscript exactly at what age green beans are introduced. However, a previous case study suggested addition of green beans at ~4 months or >44 weeks postconception.  This prior case study indicated that adding stage 2 green beans changed the caloric density of 30 cal formula to 22 cal/ounce (Nutrition in Clinical Practice 2005; 20: 674-77).  In addition, this adds 2 gm/kg/day of fiber.

Results from current study:

  • 9 of 10 IF patients were able to discontinue parenteral nutrition
  • 2 of 8 SBS patients were able to discontinue parenteral nutrition
  • All infants had improvements in stool consistency, typically within 24 hours of dietary change.

While the authors acknowledge the limitations of the study, they hypothesize that the reason for improvement is due to the fiber content of green beans.   Fermentation of dietary fiber produces short chain fatty acids (SCFAs) which in turn have a trophic effect on the mucosa and enhance nutrient absorption.

Studies have shown that adults with IF or SBS have improved stool consistency with the addition of fiber.  However, the authors note that there have been no studies documenting the effectiveness of dietary fiber in the pediatric SBS/IF population.

Whether green beans would outperform other sources of fiber like pectin, guar gum, bananas or benefiber is not clear.

Additional references/links: