Not directly low-carb, but interesting research into an obscure sugar that may become more widely used. - gotbeer
Week of Jan. 24, 2004; Vol. 165, No. 4
Cluster Buster: Might a simple sugar derail Huntington's?
Nathan Seppa, Science News
People with Huntington's disease gradually lose neurons in their brains as defective protein molecules clump together inside those cells. Scientists in Japan now report that a simple sugar called trehalose can impede this protein aggregation in test-tube and animal experiments.
Trehalose joins a growing list of potential Huntington's disease fighters (SN: 2/15/03, p. 102: Available to subscribers at http://www.sciencenews.org/20030215/fob6.asp;
11/24/01, p. 332: Available to subscribers at http://www.sciencenews.org/20011124/note13.asp
). These include proteins that prevent enzymes from triggering cell death, antibiotics, and other compounds that inhibit protein aggregation.
In an upcoming Nature Medicine, the Japanese researchers demonstrate that among mice with a version of Huntington's disease, those fed trehalose outlive their littermates and better fend off the disease.
Roughly 30,000 people in the United States have Huntington's disease, a condition marked by a loss of coordination, slurred speech, swallowing difficulties, and other problems. The illness, which usually appears in middle age, arises from an inherited genetic mutation that creates an overabundance of the amino acid glutamine in the protein called huntingtin. The excess glutamines cause unnatural folds that expose sticky portions of the protein, probably triggering the clumping inside neurons, says neuroscientist Nobuyuki Nukina of the RIKEN Brain Science Institute in Wako. Many scientists hold that this protein aggregation causes the disease.
In the new study, Nukina and his colleagues screened more than 200 compounds for their capacity to inhibit aggregation of proteins containing extra glutamines. These test-tube experiments revealed that trehalose—a sugar naturally made by organisms including yeast, bacteria, and insects—inhibits the aggregation. The sugar probably binds to some exposed portion of a glutamine-loaded protein, Nukina says. Further testing in lab dishes containing neurons from mice genetically engineered to make a portion of the human mutant huntingtin protein showed that trehalose inhibits the protein clustering.
Nukina and his colleagues then turned to live mice. In a series of tests, the scientists found that when such animals received trehalose in their drinking water, they had fewer protein aggregations in their brain cells, less brain-cell death, and better scores on coordination tests than did similar mice not getting trehalose. Survival benefits, however, were modest. On average, the trehalose-treated mice lived 108 days versus 97 days for the untreated mice. Another sugar, glucose, showed no effects.
"This is a nice, elegant study," says Robert M. Friedlander, a neurosurgeon at Harvard Medical School and Brigham and Women's Hospital in Boston. He notes that the work starts at a basic level—a hunt for compounds that bind to glutamine-loaded proteins—then tests whether the selected substance thwarts the aggregation of proteins in cells. "Remarkably, trehalose seems to work in a mouse model too," he says.
The sugar is already added to foods as a sweetener. The researchers are now considering a test of the substance as an oral drug in Huntington's patients.
Friedlander says that Huntington's disease might ultimately be treated "with a cocktail of medications . . . each with a different mechanism of action."
Trehalose might have other uses, says Christopher Ross, a neuroscientist at Johns Hopkins Medical Institutions in Baltimore. "It might be relevant to other neurodegenerative diseases that involve protein aggregations," such as Alzheimer's and Parkinson's diseases, he notes.
[I was curious about the structure of this sugar Trehalose - the "hal" might've indicated chlorine (like splenda), so I looked it up. No luck - it is just two glucose molecules bound together. Here's what I found. - gotbeer]
Trehalose General Properties
Trehalose is 45% as sweet as sucrose when compared to a 10% sucrose solution. The temporal profile of trehalose shows a rapid onset to sweetness with a persistence slightly longer than sucrose. The taste profile is nicely balanced, and the mild sweetness of trehalose can allow other flavors in food systems to be enhanced.
Trehalose is a non-reducing sugar and therefore does not react with amino acids or proteins as part of Maillard browning. Flavor, color, and nutrition are stabilized to losses in quality that would otherwise result from the Maillard reaction.
High glass transition temperature
Trehalose has a very high glass transition temperature compared to other disaccharides. This allows trehalose to remain stable under a greater range of temperature extremes, providing additional stability to glass systems into which it is incorporated. In addition, trehalose glasses are more resistant to moisture gain than other saccharide glass systems.
Chemical, acid and thermal stability
Trehalose is stable under low pH conditions where other disaccharides typically undergo various reactions, such as hydrolysis into their component monosaccharides. This minimizes caramelization and browning which are typical of low pH systems that undergo heat processing. The result is retention of more natural flavors and colors in food systems.
Exceptionally low hygroscopicity
Trehalose dihydrate is stable up to 94% relative humidity. The low hygroscopic nature of trehalose dihydrate results in a free-flowing stable dry product. In food applications where sugars are in the crystalline form, the addition of trehalose can decrease moisture sensitivity and product caking.
Stabilization of proteins and biological systems
Trehalose has been reported to be the most effective sugar for stabilizing proteins against damage caused by desiccation or freezing.
Colorless in Solution
Trehalose is clear in solution. It will not distort the natural color of the product. In some systems it has been shown to stabilize desired colors.
Trehalose, which is composed of two glucose molecules, is metabolized in an identical manner as other disaccharides (sucrose, maltose and lactose). After ingestion, trehalose is enzymatically broken down in the small intestine into two glucose molecules, which are then absorbed into the body by an active transport mechanism. Glucose is then utilized in the natural metabolic processes of life.
Trehalose was tested in vivo and in vitro cariogenic systems. It was shown to have substantially reduced cariogenic potential when compared to sucrose. Trehalose does not cause laxation typical of other non-cariogenic sweeteners.
Trehalose, produced by the Hayashibara method, was reviewed by an independent expert panel and is self-affirmed as a generally recognized as safe (GRAS) food ingredient. Trehalose is intended for general use in foods as a multiple-use direct additive. The level of trehalose in foods is limited only by good manufacturing practice for its intended use. Trehalose may function as a coloring adjunct, flavor enhancer, humectant, nutritive sweetener, stabilizer and thickener, synergist, or texturizer, as defined in 21 CFR 170.3(o). The FDA returned an "FDA has no questions" response to a GRAS notification document submitted in May, 2000.