COLUMBUS, Ohio -- Supplements that help the body create a particular antioxidant may also prevent some of the damaging physical effects caused by malnourishment, new research has shown. The finding may ultimately help provide relief to millions of people.
Malnutrition essentially causes the body to feed on itself, a process that produces high levels of cell-damaging toxins called free radicals. Some antioxidants, scarce in malnourished people, can combat those free radicals.
A new study found that when malnourished rats produced more of the antioxidant glutathione (GSH), it boosted the free-radical fighting capacities of the animals’ lungs and livers, said Tammy Bray, professor of human nutrition at Ohio State University. The research appeared in a recent issue of the Journal of Nutrition.
Results showed that using a supplement to help the body produce more GSH was more effective in protecting the rats from free-radical damage than simply replenishing the protein lacking in their diet.
“Free radical production is often increased in malnourished people,” Bray said. “This can impair their antioxidant defense system. We can help counter that by helping the body produce GSH.”
Bray said she is looking for opportunities to test GSH therapy on malnourished children in developing countries. These children would receive antioxidants orally in addition to a well-balanced diet.
Bray said that when antioxidants are not available to fight free radical production, the body is more susceptible to debilitating conditions like edema, an illness often characterized by a swollen belly caused by a build-up of fluid in body tissues and cavities.
While high levels of GSH can protect the body from free radical damage, previous research showed that supplementation of GSH itself is not effective. The key to Bray’s research was giving rats supplements of OTC (L-2-Oxothiazolidine-4-Carboxylate), a precursor that the body uses to create GSH. The body is able to take OTC to the lungs and liver, where it is turned into GSH.
“With a limited amount of resources to defend the body against free radicals, you try to design the defense so it goes directly to the target organs,” Bray said.
Bray and her colleagues fed rats a diet severely deficient in protein (0.5 percent) for 14 days. The animals were then divided into three groups for a four-day-long feeding period: one group continued on the protein-deficient diet; one received the protein-deficient diet supplemented with OTC; and the last group received a high-protein (15 percent) diet with no OTC.
The researchers also exposed the rats to intense oxygen levels during the four-day feeding period. This exposure increased the level of oxidation in the body, which helped foster free-radical production. Severely malnourished people sometimes receive similar oxygen therapy to fight lung infections.
“Unfortunately, the necessary therapy for some lung infections can increase the production of free radicals in people,” Bray said.
The rats that were fed an OTC-supplemented diet had greater protection against lung damage caused by oxidation than did rats given the protein-only diet.
The short-term therapy with the OTC-supplemented diet nearly doubled the level of GSH in the rats’ lungs. GSH levels in the liver increased almost 33 percent. The two groups lacking OTC supplementation had little, if any, increase in lung and liver GSH levels.
“Selectively elevating GSH levels in the lungs and liver was more effective in protecting tissues from free-radical damage than was giving the rats a high-protein diet,” Bray said.
Blood, which carries the OTC to the necessary tissues, lacks an enzyme necessary to turn OTC into GSH, so the OTC travels directly to the lungs and liver. OTC then combines with other compounds in these organs to form GSH.
Major organs in a malnourished body need to be stabilized during the initial phase of rehabilitation so they can do their job to fight free radicals, according to Bray. That’s why GSH therapy can be more effective than a proper diet alone.
“Enhancing the antioxidant defense system during the early phase of rehabilitation was important for the survival of these malnourished rats,” Bray said.
Other researchers included Mark Levy, a research associate in the department of human nutrition at Ohio State, and Bozena Sikorski, of the department of nutritional sciences at the University of Guelph in Guelph, Ontario.
Grants from the Ohio Agricultural Research and Development Center and Canada’s Natural Sciences and Engineering Research Council funded this study.
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