Cholesterol Medicine for Eggs?

Five years ago, a small natural-products company made waves when it marketed Cholestin, a cholesterol-lowering herbal product. The capsules contained a material made from rice fermented by a certain type of yeast. Though new to U.S. consumers, this dried version of so-called red-yeast rice has for centuries been a Chinese food coloring and herbal remedy (SN: 4/17/99, p. 255).

This product was briefly marketed in the United States as a cholesterol-lowering food additive. As its label notes (see inset), it was made from rice fermented with red yeast.

Eggs from hens treated with red-yeast rice look normal on the outside, but contain up to 14 percent less cholesterol.

The U.S. Food and Drug Administration never challenged that the new product could lower cholesterol. Why not? Because the product’s active ingredient was chemically identical to lovastatin, a federally approved anticholesterol drug. Indeed, that fact was the crux of FDA’s opposition to Cholestin (SN: 11/14/98, p. 311: The agency argued that red-yeast rice is de facto a prescription drug and should thus be dispensed as such–not as some over-the-counter food supplement.

Court battles ensued. Eventually, Pharmanex, Cholestin’s U.S. distributor, prevailed and established its right to continue marketing the product in this country as a largely unregulated food supplement (SN: 2/27/99, p. 132). Alas, notes Jia-Shi Zhu, director of clinical research for Pharmanex, insufficient market demand achieved what FDA couldn’t: It forced the company to abandon U.S. sales of the product. Pharmanex has now turned its attention to developing other food-derived products with a medicinal alter ego, such as a dried green-tea extract.

In the meantime, a Taiwanese research team has been investigating red-yeast rice as a food supplement for chickens that might in turn lay low-cholesterol eggs.

Promising results

The natural analog of lovastatin in red-yeast rice is called monacolin K. It’s produced by several yeast species in the Monascus genus as they grow on rice.

This past January, Tzu-Ming Pan of National Taiwan University in Taipei and his colleagues reported finding that a strain of Monascus purpureus is especially good at producing both monacolin K and gamma-aminobutyric acid, best known as a signaling agent in the brain. Taken orally, the latter chemical can help lower blood pressure.

Pan’s group then used batch fermenters to produce large amounts of the red-yeast rice and fed it in varying doses for 6 weeks to nearly year-old laying hens. Throughout the trial, the scientists monitored blood changes in the chickens, their eating habits, any weight changes, and their egg production.

Hens’ eggs are notorious for bringing heavy doses of cholesterol to the kitchen table. Indeed, studies have shown that eggs typically account for about half the cholesterol in U.S. diets. This includes both those eaten as a breakfast entrée and the eggs hidden in many baked foods.

Owing to the link between cholesterol and the development of flow-clogging plaque in blood vessels, doctors frequently advise people with heart disease to cut their intake of eggs.

The Taiwanese scientists reasoned that if red-yeast rice did for chickens what it does for people, farmers might have a low-cost way to make more-healthful eggs. In an upcoming issue of the Journal of Agricultural and Food Chemistry, Pan and Jyh-Jye Wang of the Tajen Institute of Technology in Pingdon confirm that hens receiving the red food additive indeed produce eggs with significantly less cholesterol than normal.

No surprise, but . . .

That came as little surprise, Pan observes, since several studies have shown that lovastatin fed to hens produces a similar trend. In those studies, however, the degree of cholesterol reduction varied dramatically from 4 to 13 percent, something Pan suspects may trace to the different ages of the chickens studied, the doses of lovastatin administered, and the amount of feed eaten.

The Taiwanese group turned to the natural product because of its long history of safe use as a food coloring and, Pan notes, the fact that the red-yeast rice’s anticholesterol ingredient costs only a tenth of a percent as much as lovastatin. Moreover, the microbial biotechnologist adds, there had been a nagging concern that residues of the prescription drug might end up in the eggs of chickens fed lovastatin–not something most people want in food, especially that being eaten by children.

To date, Pan’s group has detected no monacolin K in the test animals’ eggs. More importantly, the supplement cut the eggs’ cholesterol by almost 14 percent. That not only beat the effect of lovastatin in earlier trials, but also achieved it with less of a supplement dose.

The down side to this treatment: The egg yolks of chickens eating red-yeast rice turned dark yellow, and hens on the supplement ate more food than usual but lost a little weight. However, Pan says, farmers may see higher feed costs as an acceptable tradeoff if red-yeast rice yields eggs that consumers are less reluctant to eat than they have been.

For now, Pan’s team is focusing on ways to increase the yield of monacolin K from fermentation. Toward that end, the researchers have begun trying to ferment carbohydrates other than rice–such a corn, potato, or cassava–using red yeast.

Janet Raloff

Janet Raloff is the Editor, Digital of Science News Explores, a daily online magazine for middle school students. She started at Science News in 1977 as the environment and policy writer, specializing in toxicology. To her never-ending surprise, her daughter became a toxicologist.

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