Category Archives: Nutrition

On the Merits of Moderation: Salt, Cholesterol, and Vitamins

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At excellent overview from NY Times that explains that strict reductions in salt and cholesterol may be detrimental and that additional vitamins may be harmful. Here’s the link: Dash of Salt Does No Harm

Here’s an excerpt:

The second New England Journal of Medicine study did just that. In addition to looking at high sodium diets, it also compared the health outcomes of those who had very low sodium diets. What they found was worrisome. When compared with those who consumed 3-6 grams per day, people who consumed less than 3 grams of sodium per day had an even higher risk of death or cardiovascular incidents than those who consumed more than 7 grams per day.

This result would be shocking if we in the medical community hadn’t seen it before. But we have. In 2011, researchers published a study in the Journal of the American Medical Asssociation after following 3,681 people over almost a decade. They, too, found that excessive salt intake was associated with high blood pressure. They also found that a low-sodium diet was associated with higher mortality from cardiovascular causes….

Why experts and organizations feel the need to go from one extreme to the other is unclear. But it’s unfortunately something we do far too often in medicine.

Take cholesterol. Initially, people believed that the evidence was pretty compelling that high cholesterol was bad for you…Eggs were shunned. But later research showed us that egg consumption had no relationship to cardiovascular disease for most people. In fact, a majority of people’s serum cholesterol level has little to do with how much cholesterol is in their diet. Today we use medications to lower our cholesterol levels. Once again, though, our sights keep shifting lower…

We have to learn that when one extreme is detrimental, it doesn’t mean the opposite is our safest course.

Preventing Picky Eating Habits

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According to several studies in Pediatrics and summarized in NY Times, preventing picky eating habits and developing good diet habits relies on #1) introduction of fruits and vegetables in the first year of life and #2) avoid sugar-sweetened beverages in infancy.

NY Times Food Introduction Article

Here is an excerpt of the summary:

The package of 11 studies was published in the journal Pediatrics and was funded by the Centers for Disease Control and Prevention and the Food and Drug Administration, among others. Investigators tracked the diets of roughly 1,500 6-year-olds, comparing their eating patterns to those observed in a study that followed them until age 1…

As it turns out, “when infants had infrequent consumption of fruits and vegetables, they also had infrequent consumption at 6,” said Kelley Scanlon, an epidemiologist at the C.D.C. and the senior author of a few of the new studies.

Dr. Scanlon and her colleagues suggested that it is best to interest children in fruits and vegetables by late infancy — roughly between 10 and 12 months old.

Another study in the new series found that babies who consumed any amount of sugar-sweetened beverages were two times more likely to drink them at least once daily at age 6. A third study found that infants ages 10 to 12 months who were given sugar-sweetened beverages more than three times a week were twice as likely to be obese at age 6 than those who consumed none as infants.

Their analysis took into account factors that could skew results, like race, family income and breast-feeding. ..Breast-fed infants are more accepting of new foods than babies who drank the same-tasting formula day after day, research has shown. A C.D.C. study in the new series found that children who were breast-fed were more likely to consume water (versus sugar-sweetened beverages), fruits and vegetables at age 6.

Related blog post:

Sweetened Beverages -A Big Problem for Little Kids …

Reading Past the Headline: Low Fat vs Low Carb

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A recent study purportedly showed that a low-carb diet is superior to a low-fat diet.  However, David Katz explains how this study was flawed.  Here’s the link: Huffington Post “Low-fat” versus Low-carb and here’s an excerpt:

It was published in the Annals of Internal Medicine.. Allegedly, the researchers compared a low-fat to a low-carb diet. But in fact, they compared a diet that allowed up to 30 percent of calories from fat to a diet that allowed up to 40 grams of daily carbohydrate…

baseline carbohydrate intake was 240 grams per day, so while fat intake was “trimmed” 5 percent, carbohydrate intake in that assignment was slashed 75 percent. This might have been billed “a study to compare a really big change from baseline diet to a really small change from baseline diet.”…

the low-carb diet, since it was actually low-carb, obviously was much more restrictive than the low-fat diet, which wasn’t actually low-fat. That had the predictable result: those on the low-carb assignment took in many fewer calories…

I am not an advocate of low-fat diets. I think the concept is obsolete. I am an advocate, based on the evidence, of wholesome foods in sensible combinations. That dietary pattern can be low or high in fat, relatively lower or higher in carbohydrate.

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Low-FODMAPs with or without Gluten-Free Diet in IBS

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In a small study with 60 patients with irritable bowel syndrome (DDW abstract 374), the response rate to a Low-FODMAPs/Normal gluten diet was as effective as a Low-FODMAPs/Gluten-free diet.  Both diets were more effective in reducing abdominal symptoms than a normal diet.  A summary of this abstract from Gastroenterology & Endoscopy News: Nixing Gluten Offers No Added Benefit To Low-FODMAPs Diet for IBS

According to Lin Chang, MD: “The beneficial effect of low FODMAPs does not appear to be predominantly due to gluten avoidance.”

Related blog post: An Unexpected Twist for “Gluten Sensitivity” | gutsandgrowth

 

“Bacterial Penetration Cycle Hypothesis”

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Initially, this blog was titled: “Even More Work for Our IBD Nutritionists?”  If you get to the bottom of this post, you will know why.

A provocative study (Inflamm Bowel Dis 2014; 20: 1353-60) describes the use of partial enteral nutrition (PEN) as effective for induction of remission in children and young adults with Crohn’s disease (CD).  I’m a little wary commenting on this study as many individuals may take a glimmer of information and subject themselves to empiric trials.  In fact, a recent case report (N Engl J Med 2014; 371:668-675) described an adult who without medical advice used fecal transplant therapy (obtained from spouse and infant) to self-treat his ulcerative colitis.  In the case report, this patient ultimately was diagnosed with a secondary cytomegalovirus (CMV) infection and the fecal transplant was not effective.

With regard to the PEN study, the authors treated 47 patients (34 children) with up to 50% of their diet as a polymeric formula (Modulen or Pediasure) along with dietary counseling/changes.  The authors note that CD “may arise from a sequence of events involving changes in the microbiome, intestinal permeability leading to bacterial adherence or penetration of the epithelium, and subsequent stimulation of the adaptive immune response leading to tissue damage.  We have termed this sequence the Bacterial Penetration Cycle Hypothesis.”  Given the compelling improvements noted with exclusive enteral nutrition (EEN), the authors sought to modify the diet after an initial clinical response in two patients who could not adhere to EEN.

Design: Strict diet for 6 weeks with 50% of calories from formula, then less restricted diet for next 6 weeks (25% of calories from formula).  Also, diet required exclusion of gluten, dairy, animal fat, processed meats, products containing emulsifiers, candies, chocolates, gum, packaged snacks, sauces, and canned goods.  A more extensive listing of the foods is given in the appendix (page 1360).  The authors measured the clinical response with PCDAI, Harvey Bradshaw index, and bloodwork (eg. CRP, ESR, albumin, and hemoglobin).

Key finding:

  • 33 (70.2%) achieved a remission on this PEN diet; 78.7% (n=37) had a clinical response.
  • Normalization of CRP occurred in 21 of 30 patients (70%) of those with a clinical remission.

Take home message: A PEN diet needs more study.  I would not advise someone to radically change their diet without the instruction of a qualified nutritionist, unless the individual wants to be another case report of something gone awry.

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Nutrient Deficiencies with Celiac Disease

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A recent study (JPGN 2014; 59: 225-28) examined fat-soluble vitamin deficiencies in pediatric patients with newly diagonosed Celiac disease (CD).

Of the 83 patients analyzed between 1995-2012 at the Mayo clinic, the key findings:

  • No patients had vitamin A deficiency
  • Two patients had vitamin E deficiency.  Both of these patients had complete villous atrophy along with a malabsorptive presentation.
  • Nine patients had mild-to-moderate vitamin D deficiency (less than the reported frequency in the general pediatric population)
  • All of these vitamin deficiencies corrected with gluten-free diet and vitamin supplements.

A limitation of the study was a selection bias as not all children underwent vitamin level measurements.

Take-home message (from authors): “fat-soluble deficiencies are uncommon in children with a new diagnosis of CD.  Routine measuring of fat-soluble vitamin levels may not be necessary.”

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One More Way to Prevent CVL Infections

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While a recent study (JPGN 2014; 59: 177-81) discusses the results of several strategies for limiting CVL infections, I found one approach in particular of interest.

This single center study (2009-2013, n=48 children) from Birmingham, UK examined a multidisciplinary enhanced care pathway regarding CVL care.  Implementation of this pathway lowered the risk of all-cause line infections from 1.98 per 1000 parenteral nutrition days to 0.45.  The pathway included training care providers, careful discharge planning, having those with skin conditions see dermatologists, and monitoring compliance.

One important observation was that methicillin-sensitive Staphylococcus aureus (MSSA) infections were often preceded by local signs of infection for a short period prior to systemic infection.  “We devised a pathway for exit site infections in which a swab is taken and empiric topical mupirocin commenced immediately. A decision on any further management is made after 24 to 48 hours.”

Take-home message: Implementing a CVL care pathway lowers CVL infections.  Implementing topical therapy at the first signs of a localized infection can be an important part of this effort.

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Why Adding Vitamin D May Not Help IBD

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Despite all of the accolades that vitamin D has received, the fact that low vitamin D is associated with worse outcomes, in a number of disease states, does not prove causality. A recent article indicates that vitamin D is likely more of a marker of disease activity than a mediator of disease activity in inflammatory bowel disease (IBD), and specifically Crohn’s disease (CD) (Inflamm Bowel Dis 2014; 20: 856-60).

Background: Binding sites for the vitamin D receptor (VDR) have been “identified in genes associated with CD, and vitamin D has been shown to enhance the production of interleukin-10 (IL-10) and induction of regulatory T-cells.”

Design:The authors prospectively collected samples of 37 CD patients; the mean age in those with active disease (n=20) was 34 years and it was 30 years in those with inactive disease. In 8 patients with active disease, vitamin D levels were measured at the time of active inflammation (day 0) and at 14 days after receiving infliximab (day 14).

  • Key finding in these 8 patients: Vitamin D (25-OH) was 23 ng/mL on day 0 and 40 ng/mL 2 weeks later.  Only 1 of these 8 patients was taking a vitamin D supplement.
  • Key finding in the entire cohort: in the active disease group mean vitamin D level was 27 ng/mL compared with 38 ng/mL in those in remission (P=0.02).

Take-home point: There is an inverse relationship between vitamin D levels and disease activity.  However, the early increases in vitamin D levels with clinical response to anti-TNF therapy suggests that a major mechanism of vitamin D deficiency is related to the burden of systemic inflammation.  Hence, repeat testing when patients are in remission may obviate the need for vitamin D supplementation in many patients.

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Enteral Fish Oil and Intestinal Adaptation in Premature Infants

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A provocative article (J Pediatr 2014; 165: 274-9) examines supplementation of enteral fat/fish oil in premature infants as a mechanism to reduce parenteral nutrition associated cholestasis (PNAC).  While the study’s limitations will prevent any dramatic conclusions, the article and associated editorial (pgs 226-27) do make several useful points.

Before discussing the limitations, the design of the study:

Infants were block randomized (block size of 8) into either a control group or treatment group.  While both groups received conventional PN, the treatment group received supplemental enteral fat as microlipid and fish oil after tolerating enteral feeds at 20 mL/kg/d.  Microlipid was started at 1 g/kg/d and advanced up to 2.5 g/kg/d; coinciding with microlipid increases, parenteral intralipid was decreased.  Fish oil was started at 0.2 g every 12 hours and was advanced to a maximum of 0.5 g every 6 hours.  The two fish oil products were Major Fish Oil 500 (Major Pharmaceuticals) and Rugby Sea Omega 50 (Rugby Laboratories).

The limitations include the following:

  • Small cohort of 18 patients in each arm
  • Due to the smell of fish oil, the study could not truly be blinded which introduces potential bias
  • Only 7 of the 36 patients could be considered to have short bowel syndrome as most of the infants had small amounts of intestine resected
  • Advancement of enteral feedings were halted if stoma output reached 20 mL/kg/d.  The editorialists note that 40 mL/kg/d would be more typical.  Thus, in both the treatment group and the control group, there was significant opportunity to reduce PN by more aggressive enteral nutrition advancement.

With these limitations in mind, there authors were able to show that supplemental fat (with fish oil) was associated with less parenteral intravenous lipid, and reduced conjugated bilirubin prior to anastomosis.  However, there was no significant difference in PN duration.  Growth parameters were similar prior to anastomosis, but improved in the treatment group after anastomosis.

In the editorial, it is noted that “enteral feeding with a high-fat diet has been demonstrated to enhance structural features of resection-associated adaptation, the underlying mechanisms for this phenomenon are still presently unknown.”

Take-home message: Enteral fat/fish oil supplementation helped decrease parenteral intravenous lipids in this study.  More broadly, advancing enteral nutrition by accepting higher ostomy outputs is likely the best strategy to avoid PNAC and other PN-associated complications.

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