ECHINACEA MAY NOT DETER COLDS

Source: S Sperber et al., "Echinacea purpurea for Prevention of Experimental Rhinovirus Colds," Clinical Infectious Diseases 38, no. 10 (May 15, 2004): 1367–1371.

Although echinacea is often taken to fight colds and alleviate cold symptoms, the results of a small study suggest that the herb may not have much of an effect.

In the study, which was published in the May 2004 issue of Clinical Infectious Diseases, researchers inoculated 48 healthy adult volunteers with rhinovirus type 39, a strain that causes colds. The volunteers then received either 2.5 ml of echinacea or a placebo three times per day for seven days before and seven days after inoculation. More than 90% of the participants ultimately became infected.

According to the researchers, while 58% of the echinacea recipients and 82% of the placebo recipients developed colds, "administration of echinacea before and after exposure to rhinovirus did not decrease the rate of infection." The researchers noted that the small sample size hindered their ability to detect statistically significant differences.
 

CITRUS COMPOUNDS MAY IMPACT CHOLESTEROL

Source: E Kurowska and J Manthey, "Hypolipidemic Effects and Absorption of Citrus Polymethoxylated Flavones in Hamsters with Diet-Induced Hypercholesterolemia," Journal of Agriculture and Food Chemistry 52, no. 10 (May 19, 2004): 2879–2886.

Flavonoids found in citrus peels may have a beneficial effect on cholesterol levels, according to the results of a small animal study published in the May 19 issue of the Journal of Agriculture and Food Chemistry.

Hamsters that were fed a diet containing citrus polymethoxylated flavones (PMFs), such as tangeretin, experienced a drop in very-low-density and low-density lipoprotein (LDL) cholesterol levels of 32–40%. The PMFs also reduced serum cholesterol levels by 19–27%, according to the researchers.

Two other citrus compounds, the flavanone glucosides hesperidin and naringin, had similar effects on cholesterol but required greater amounts to perform comparably.

LOW-CARB DIETS TESTED FOR WEIGHT LOSS

Source: W Yancy et al., "A Low-Carbohydrate, Ketogenic Diet vs. a Low-Fat Diet to Treat Obesity and Hyperlipidemia," Annals of Internal Medicine 140, no. 18 (May 18, 2004): 769–777.

Source: L Stern et al., "The Effects of Low-Carbohydrate vs. Conventional Weight-Loss Diets in Severely Obese Adults: One-Year Follow-Up of a Randomized Trial," Annals of Internal Medicine 140, no. 18 (May 18, 2004): 778–785.

Low-carbohydrate diets appear to help promote weight loss and improve triglyceride and high-density lipoprotein (HDL) cholesterol levels, according to the results of two studies published in the May 18, 2004, issue of the Annals of Internal Medicine.

In the first study, 120 overweight volunteers followed either low-carb or low-fat diets for 24 weeks. Those on the low-carb diet ate less than 20 g of carbohydrates per day and received some nutritional supplementation, while those on the low-fat diet obtained less than 30% of their calories from fat.

After 24 weeks, the low-carb group lost more weight than the low-fat group (–12.9% versus –6.7%); the low-carb group was also more likely to complete the study than the low-fat group (76% versus 57%) and experienced greater increases in HDL cholesterol.

In the second study, 132 obese adults followed either a low-carb or a low-fat diet for one year. Those in the low-carb group ate less than 30 g of carbohydrates per day and those in the low-fat group obtained less than 30% of their calories from fat.

After one year, individuals on the low-carb diet lost more weight than those on the low-fat diet, but the differences between the two groups were not statistically significant. The low-carb group also saw a greater decrease in triglyceride levels than the low-fat group and a small increase in HDL levels.

The researchers from both studies noted that the high dropout rates and difficulty of following the diets made it difficult to generalize the study findings. In an editorial accompanying the studies, Walter Willet, MD, professor of nutrition and epidemiology at Harvard's School of Public Health (Cambridge, MA), warned that "the roll will have little role" unless dieters emphasize healthy eating patterns and engage in regular physical activity.

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