May 11, 2012
Grapefruits Can Treat Disease As Well As Pharmaceuticals Without The Side Effects
In the never ending saga of natural disease fighting foods beating out pharmaceuticals, the grapefruit is another power packed citrus fruit to add to the the list. It actually never really gets the credit it deserves for preventing disease. But it can and without the side effects caused by pharmaceuticals. Grapefruits can prevent weight gain, treat diabetes, lower cholesterol, fight cancer, heal stomach ulcers, reduce gum disease and even keep stroke and metabolic syndrome at bay.
Naringenin, an antioxidant which gives grapefruit its bitter taste, can do the same job as two separate drugs currently used to manage Type 2 diabetes, scientists said.
Naringenin has also been found to correct the elevations in triglyceride and cholesterol, preventing the development of insulin resistance and completely normalizing glucose metabolism. Researchers have found it works by genetically reprogramming the liver to burn up excess fat, rather than store it.
Naringenin helps to increase the body’s sensitivity to insulin. It also helps sufferers maintain a healthy weight, which is a vital part of diabetes treatment.
Antioxidants found in grapefruits can do the same job as two drugs used to treat Type 2 diabetes. Researcher Dr Martin Yarmush Remarka said: "The liver behaves as if fasting, breaking down fatty acids instead of carbohydrates."
Yaakov Nahmias, from the Hebrew University of Jerusalem, hailed naringenin as a ‘remarkable’ treatment for diabetes.
The so-called grapefruit diet -- which advocates mostly eating grapefruit with some protein -- has been popular on and off for weight loss for years, said Dr. Ken Fujioka, director of nutrition and metabolism research at the Scripps Clinic in San Diego and lead author of a study evaluating grapefruit for weight loss. Most nutrition experts have deemed the grapefruit-and-protein regimen unhealthy, and Fujioka is not advocating any return to such a strict diet.
However, his findings do suggest that a grapefruit or two each day, added to a balanced diet, might help the weight-conscious stay svelte.
At the end of a 12 week study a placebo group lost on average just under half a pound, while a grapefruit extract group 2.4 pounds, the grapefruit juice group 3.3 pounds, and the fresh grapefruit group 3.5 pounds.
"In this study they had one and a half grapefruits a day," he noted. "That's not easy to do." And participants ate the fruit more like an orange: "They cut it in half, then into four sections, then separated the fruit from the skin." Eating grapefruit this way is thought to yield more beneficial compounds, he explained.
Exactly how grapefruit might spur weight loss isn't known, Fujioka said, but "it appears to help insulin resistance," which develops as people become obese.
The weight loss associated with eating grapefruit isn't surprising to another expert familiar with the study. "Eat fruit before any meal and you will lose weight," said Julie Upton, an American Dietetic Association spokeswoman. "The fiber fills you up, and fruit has fewer calories than other foods."
In another second study, grapefruit juice helped decrease the activity of an enzyme that makes cigarette smoke more carcinogenic.
Kristine Cuthrell, a research nutritionist at the University of Hawaii's Cancer Research Center, gave 49 smokers grapefruit juice or another test food, onions. Then they evaluated their urine to evaluate the activity of a liver enzyme called CYPIA2, thought to activate the cancer-causing chemicals found in tobacco smoke. Those who drank three six-ounce glasses of grapefruit juice a day reduced the activity of the enzyme, she said.
Other studies have also found that foods rich in flavonoids, like grapefruit, can inhibit the activation of a carcinogen, Cuthrell said.
The finding that grapefruit juice reduced the activity of the enzyme linked with making smoke more carcinogenic is also not surprising, Upton said, since a multitude of studies link eating a diet rich in fruits and vegetables with lowering cancer risk.
Polish researchers found that grapefruit extract can help to heal stomach ulcers, due to its strong antibacterial and antioxidant properties, which calm the gastric tract and aid the healing process.
The researchers induced gastric ulcers in rats, and applied graded doses of the fruit extract to measure its effect.
In particular, they looked at levels of gastric secretion - one of the major causes of gastric ulcers.
Rats treated with GSE at 10 mg/kg experienced a 50% reduction in gastric acid secretion, and a progressive decrease in the area of their ulcer.
The treatment also prompted a significant rise in blood flow at the ulcer sites - another phenomenon that can aid healing.
The beneficial effects, however, were diminished in the presence of drugs which inhibit two enzymes, COX-1 and COX-2, which play a key role in maintaining the health of the stomach lining.
The researchers believe that the grapefruit extract somehow joins forces with these enzymes to promote healing.
Lead researcher Dr Thomas Brzozowski said: "Because grapefruit is acidic in nature, people with ulcers might assume that they should not include the fruit in their diet.
"However, this research suggests the exact opposite."
Dr Lee Kaplan, of Massachusetts General Hospital, said: "Incorporating healthy eating habits and lifestyle choices can directly benefit digestive and overall health over the long term."
Animals fed a high fat diet and supplemented with the flavonoid naringenin did not gain weight, while other signs of the metabolic syndrome were also prevented, according to findings published in the journal Diabetes.
“The marked obesity that develops in [mice fed a high fat diet] was completely prevented by naringenin,” said lead researcher Murray Huff from the University of Western Ontario.
“What was unique about the study was that the effects were independent of caloric intake, meaning the mice ate exactly the same amount of food and the same amount of fat. There was no suppression of appetite or decreased food intake, which are often the basis of strategies to reduce weight gain and its metabolic consequences,” he added.
The animals fed only the high-fat diet became insulin and glucose intolerant, and obese. However, supplementation with the flavonoid reversed the increases in triglyceride and cholesterol levels, prevented the development of insulin resistance and completely normalized glucose metabolism, said the researchers.
Research from Germany showed that eating two grapefruits a day for two weeks appears to significantly cut gum bleeding for people who have gum disease.
The researchers from Friedrich Schiller University said the grapefruit increases blood levels of vitamin C, which is known to promote wound healing and cut damage by unstable free radical molecules.
The study of 58 people with chronic gum disease, published in the British Dental Journal, showed that eating grapefruit had a positive effect on both smokers and non-smokers, the BBC reported. Smoking is known to increase the risk of gum disease.
Isn't time we all start eating a grapefruit a day to keep everything at bay?
Natasha Longo has a master's degree in nutrition and is a certified fitness and nutritional counselor. She has consulted on public health policy and procurement in Canada, Australia, Spain, Ireland, England and Germany.