March 29, 2006
Everyday Foods May Yield Medicinal Benefits
Chives, grape seeds and pine nut oil all show early promise, researchers say
Grape seeds, chives and Korean pine nut oil might have more in common than their ability to add zest to meals.According to new research, all three foods may help boost health and fight disease.
The three studies were presented March 26-28 at the American Chemical Society annual meeting, in Atlanta. They highlight, respectively, grape seed extract's ability to lower blood pressure; chives' capacity to protect against salmonella and other food-borne illnesses; and pine nut oil's power to suppress appetite.
Although the results are preliminary, they point the way to more in-depth studies, the researchers said.
"I am very optimistic about our research," said chive study lead researcher Salam A. Ibrahim, from the department of food science and nutrition at North Carolina A&T State University, in Greensboro, N.C.
Ibrahim and his colleagues noted that although many plant, herb and mushroom extracts demonstrate antimicrobial properties, chives seem to have the most potent effect against 38 strains of salmonella -- the most common bacterial food-borne illness.
The researchers purchased chives from a local Greensboro store and cut, blended and mixed down the food to obtain chive extract.
Lab tests with various quantities of the extract revealed that, in sufficient quantities, chives can inhibit salmonella activity without the need for additional irradiation or chemical preservatives.
However, when the chive extract was heated above 121 degrees Celsius for 15 minutes the antibacterial effect was completely lost.
As well, Ibrahim noted that the 800 microliters of chive extract needed to produce a 100 percent protective effect against salmonella was much higher than most people would find appetizing.
One solution to the problem might be through combining of chives with other natural and/or chemical preservatives. "We have a formula that looks very promising and has no effect on flavor, while at the same time protecting against salmonella," Ibrahim said.
In the meantime, adding chives to everyday foods should still be considered a healthy move, he said.
Grape seed extract may have its own health benefits, another study showed. The study involved 24 men and women diagnosed with "metabolic syndrome," a condition characterized by cardiovascular risk factors such as high blood pressure and obesity.
After four weeks, patients who had consumed either 150 milligrams or 300 milligrams of grape seed extract a day experienced a significant drop in both systolic and diastolic blood pressure, while those taking a placebo underwent no change.
"I think this is not going to be a standard treatment for high blood pressure, I want to make that clear," said researcher Dr. G. Tissa Kappagoda, of the department of internal medicine at the University of California at Davis. "But it may be a potential tool for people who are prehypertensive, as part of a lifestyle management routine that includes weight management and exercise. In that context, grape seed extract may prove useful."
The third study was led by Jennifer L. Causey, of Lipid Nutrition Co. Her work focused on Korean pine nuts and their potential effect on weight loss.
Causey explained that the nuts contain a high amount of an oil called pinolenic acid, which has been shown in laboratories to stimulate the release of two appetite-suppressing hormones, CCK and GLP1.
The study involved 18 overweight women. In the four-hour period following consumption of 3 grams of the pinolenic acid in gel capsule form, hormone levels were found to rise, and the women's appetites fell by approximately a third.
These fatty acids have been found to impact satiety, or the feeling of fullness, and may be beneficial as part of a weight-loss program that includes diet and exercise, Causey said. The results are exciting from a consumer perspective, since they show scientific evidence for a satiety effect, she said.
Causey added that more studies are currently in the works.
Dr. Ken Fujioka, director of the department of nutrition and metabolism within the department of endocrinology at the Scripps Clinic in San Diego, expressed support for the preliminary findings.
"All [these foods] certainly have the possibility to do what the researchers saw," he said. "The pine nut, in particular, has been noted before as an appetite-controller, so their finding makes sense. The question would be, 'Is it enough to make a clinical difference?' And it could very well do that. The chives finding is not surprising either ... and could be a great idea to help cope with a meal that maybe we shouldn't have eaten. And many blood pressure medications -- particularly the earlier ones -- started off from natural plant sources. So, all of these findings seem reasonable."
While agreeing that the research holds considerable promise, Lona Sandon, a spokeswoman for the American Dietetic Association, cautioned that the use of food to alleviate medical concerns is not always as simple as it seems.
"For example, they've been looking at grapes for years, so it's not that surprising, but I'm concerned that the extract alone is not the best choice," said Sandon, who is also assistant professor of clinical nutrition at the University of Texas Southwestern Medical Center, Dallas. "There are so many components in the grape that act together synergistically to give you the biggest bang for your buck, that if you take one out you may not be getting the full benefit for your health."
"And although I'm not that familiar with the pine nut research," added Sandon, "I would want to know how much you would have to eat to get this result, because if it's a lot then you're taking in a lot of fat and calories to get the appetite-suppressing effect. As well, while adding chives might be an organic way to protect produce, it's not a replacement for what we do in the kitchen: washing hands, proper storing of food at proper temperatures, and the need to cook foods at proper temperatures."
For more on food and health, visit the American Dietetic Association.