Page 45 - Today's Dietitian (March 2020)

example, iron, a necessary mineral certain gut bacteria may help improve experienced significant weight loss and
for almost all living species, interacts absorption by breaking down these sub- disruptions in protein and carbohydrate
extensively with gut bacteria. Free iron stances into smaller components or metabolism. The results of this study
is scarce in the gut, so microbes must converting them into absorbable sub- indicate that the gut microbiome may
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compete for the iron that’s available. stances. However, further research is be responsible for the differences in
Pathogenic bacteria have greater iron needed to evaluate the complex inter- nutritional status between children
needs than do beneficial bacteria. action between phytonutrients and the within the same household, particularly
Since iron is limited, the scarcity of this microbiome. in developing countries. 27
important mineral slows the growth Without gut microbes, humans may A smaller study of healthy vs mal-
of pathogenic bacteria. In developing be at risk of developing vitamin and nourished children in Bangladesh also
countries where people are more mineral deficiencies and also would lose evaluated the impact of the gut microbi-
susceptible to infectious diseases, the benefit of many antioxidants due ome on nutritional status. Fecal samples
low hygiene, and gut inflammation, to the inability to efficiently digest and were collected from seven healthy and
there’s an increase in morbidity and absorb phytonutrients. The gut micro- seven malnourished children between
mortality with iron supplementation, biome assists in the absorption of these the ages of 2 and 3. The samples were
particularly in children. It’s believed important nutrients, improving nutri- then evaluated, and healthy children
that supplemental iron administration tional status and health. were found to have significantly greater
enables pathogenic bacteria to thrive in gut microbiota diversity when compared
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an already compromised gut. The Microbiome and Malnutrition with malnourished children. The healthy
The gut microbiome also influences Undernutrition, common in many coun- children also had more of the Bacteroide-
the absorption and utilization of phy- tries, is responsible for approximately tes and Firmicutes strains; each of these
tonutrients, plant compounds that are 45% of childhood deaths. Based on phyla composed approximately 44% of
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beneficial to health and don’t fall into observations of nutritional status from their microbiomes. On the other hand,
the category of micronutrients. These developing countries, malnutrition isn’t the microbiomes of the malnourished
include compounds such as terpenoids, always simply a result of inadequate cal- children were 18% bacteroidetes and 32%
chlorophylls, and polyphenols. Phytonu- ories; there can be nourished and under- firmicutes. The microbiomes of the mal-
trients have antioxidant properties and nourished children living in the same nourished children were composed of
are thought to be critical for preventing household. One reason this discrepancy 46% proteobacteria, compared with only
disease. In general, phytonutrients aren’t may occur is that the gut microbiome 5% in the healthy children. The malnour-
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well absorbed in the digestive tract, but influences the risk of malnutrition. ished children also were more likely to
A 2013 study of monozygotic and have more pathogenic bacteria, such as
dizygotic twins in Malawi aimed to eval- enterobacteria, present in their guts. 28
uate the impact of the gut microbiome The type of bacteria found in the gut
on kwashiorkor. Researchers studied 317 is believed to be important in determin-
twin pairs in their first three years of ing nutritional status. Bacteroidetes are
life. One-half of the twins remained well generally responsible for the breakdown
nourished during the study period, but of complex fibers and the synthesis of
in 43% of the twin pairs, at least one sib- short-chain fatty acids. They can help
ling developed malnutrition. In 7% of the extract energy from a variety of foods.
twin pairs, both siblings were diagnosed Firmicutes have been indicated to influ-
with kwashiorkor. ence calorie absorption. A microbiome
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The children who developed mal- with reduced quantities of these particu-
nutrition were treated with a peanut- lar strains may decrease calorie absorp-
based, ready-to-use therapeutic food, tion and cause malnutrition even when
resulting in improvement. Their gut adequate calories are consumed.
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microbiomes were evaluated before and In addition, pathogenic bacteria in
after the treatment. Those with mal- the subjects with malnutrition indicate
nutrition were found to have poor gut the presence of subclinical infections of
maturation and a lack of diversity and the gastrointestinal tract, which may,
supportive bacteria, indicating a dys- in turn, result in poor nutrient absorp-
functional gut microbiome. The guts of tion and worsening malnutrition. The
the children matured during treatment authors of this study mention that other
with the therapeutic food but regressed studies involving malnourished chil-
once the treatment ended. 27 dren haven’t found the same phyla to
After the study was completed, be universally dominant or problem-
frozen fecal samples from the children atic, meaning that environment, food,
with malnutrition were transplanted and geography may play a role in deter-
into germ-free mice. When fed a mining which bacteria are harmful and
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typical Malawian diet, the mice which can trigger malnutrition.
MARCH 2020 • WWW.TODAYSDIETITIAN.COM 45