Brown Seaweed May Be a Fat Fighter
Compound targets abdominal fat in animal studies
MONDAY, Sept. 11, 2006 (HealthDay News) -- That tasty miso soup you had for lunch may be more than delicious -- it could help you burn away excess fat.
That's the conclusion of preliminary research presented Monday at the American Chemical Society's annual meeting, in San Francisco.
Researchers led by Kazuo Miyashita, a chemistry professor at the Hokkaido University Graduate School of Fisheries Sciences in Japan, investigated the effects of brown seaweed, Undaria pinnatifida -- a type of kelp called wakame that is widely consumed in Japan.
They found that fucoxanthin, the brown pigment in the seaweed, promoted a 5 percent to 10 percent weight loss in mice and rats by shrinking abdominal fat. The compound appeared to stimulate a protein that causes fat oxidation and conversion of energy to heat. This protein is found in white adipose tissue -- belly fat -- and that means fucoxanthin might be particularly effective at shrinking oversized guts, the researchers hypothesized.
Fucoxanthin also stimulated the animals' livers to produce DHA, a beneficial omega-3 fatty acid that reduces low-density lipoprotein (LDL), the bad cholesterol that contributes to atherosclerosis.
"The exciting finding is that fucoxanthin may increase metabolism and weight control," said Connie Diekman, director of University Nutrition at Washington University in St. Louis. "But the downside is that this is an animal study, and we can't automatically translate from animals to humans."
Fucoxanthin belongs in the phytochemical food category, and these foods have a lot of benefits, Diekman added. But she cautioned that, "we need to look at these studies for their interest but [also] recognize that the bottom line is, there is no magic when it comes to weight control."
Lona Sandon, an assistant professor of clinical nutrition at the University of Texas Southwestern Medical Center at Dallas, agreed. "Fucoxanthin potentially could help control weight, and help produce more heart-healthy DHA. But these are very preliminary studies done at the molecular level on rats, not on humans," she said. "So, although it looks promising, we've got a long way to go before we know that eating seaweed will keep our waistlines thin."
Consumers should understand that clinicians and researchers have a "whole lot to learn about weight control in humans and this is one study in a long investigation," Diekman cautioned. "Don't give up on what we know will work -- correct food choices, right portions and regular physical activity. It's hard, but magic isn't going to help you be healthier. A healthier lifestyle is the key."
Still, the Japanese researchers hope that further study could eventually lead to a pill containing fucoxanthin that might be consumed daily or as needed. That pill will be a long time in the making, however. Even though human studies are planned, it will likely be at least five years before a fucoxanthin-based anti-obesity pill would be available to consumers. Until then, people should continue to eat a well-balanced diet and get plenty of exercise, Miyashita said in a prepared statement.
Seaweed isn't the only food promising medicinal powers. According to research presented at the same meeting by scientists at Kyoto Prefectural University of Medicine in Japan, mandarin oranges may reduce the risk of liver cancer in patients with chronic viral hepatitis. After one year, no liver cancer was detected in 30 patients who drank one cup daily of a beverage containing mandarin orange juice. On the other hand, 8.9 percent of 45 patients who didn't drink the beverage developed liver cancer.
In other research presented at the meeting, a team at the National Institute of Fruit Tree Science in Japan surveyed 1,073 Japanese people who consumed large amounts of mandarin oranges. They report that chemical markers in the subjects' blood were associated with a lower risk for liver disease, atherosclerosis, and insulin resistance, which can lead to diabetes.
And there's more good food news -- wheat, corn, and rice flour can be modified into an enhanced product that makes the flour's antioxidants more available to the body, according to University of Maryland researchers.
Those same researchers also say they've developed a new type of flour from fruit seeds -- normally waste products from the processing of juice and fruit products. In laboratory studies, the fruit-seed flour appears to have the ability to fight inflammation, cancer and food-borne bacteria, the scientists said.
Finally, researchers at Nihon University in Japan reported that they've made the calcium in soybeans more easily absorbed, by removing an absorption-hindering chemical called phytate. They also modified two amino acids in soybeans so that they form a whiter, smoother product and retain the original taste.
To learn more about weight control, visit the National Institute of Diabetes and Digestive and Kidney Diseases.