Obesity

Extract from Grapefruit may Prevent Obesity and Metabolic Syndrome

A new study has revealed that a chemical compound found in grapefruit may aid in preventing physiological changes, which lead to an adverse condition called metabolic syndrome. Metabolic syndrome is a group of symptoms that occur together and increase the risk for stroke, coronary artery disease and type 2 diabetes.  The two strongest risk factors for metabolic syndrome are obesity or excess fat around the middle and upper parts of the body and insulin resistance.  Age, genes, lack of exercise and hormonal changes can also add to the risk of metabolic syndrome. A person is diagnosed with metabolic syndrome if they have three or more of the following criteria: high fasting blood sugar levels, low HDL or good cholesterol, abdominal obesity or high waist circumference, high triglycerides and/or high blood pressure.

A few studies have suggested that a chemical substance or a combination of substances in grapefruit might help in regulating blood sugars and fats.  One of the studies, published in the Journal of Agricultural and Food Chemistry, found that individuals who consumed one fresh red grapefruit every day might decrease their levels of cholesterol by nearly 15 percent and triglycerides levels by 17 percent, both associated with metabolic syndrome when at higher levels.   The experiments conducted in humans and in lab studies indicated that the grapefruit could act through other ways in the body to minimize the risk of heart disease.

Another study, by a team of researchers from the University of Western Ontario, found that the flavonoid found naturally in grapefruit, naringenin, might perform similarly to that of the hormone insulin, which helps regulate blood sugar levels in the body. Naringenin was also found to inhibit the liver from secreting very low-density lipoproteins or LDL, the “bad” cholesterol. This helped reduced the levels of certain triglycerides in the blood. All of these findings could help to fight off some of the typical characteristics of metabolic syndrome.

The newest study, published in the medical journal, Diabetes, followed up on the study of naringenin using live mice.  The same team of researchers from the University of Ontario carried out the study. They initially bred specific mice to be deficient in low-density lipoproteins (LDL) receptors in their livers.  Since LDL carries cholesterol, a receptor deficiency leads to high levels of blood cholesterol. When these mice were fed a high-fat diet, they became prone to obesity and other typical symptoms of metabolic syndrome. When they were 8-12 weeks old, the modified mice were separated into 4 groups based on their diet:

  • Normal diet
  • High-fat diet
  • High-fat diet with 1% naringenin
  • High-fat diet with 3% naringenin

After four weeks of observation, they found that the mice fed the high-fat diet developed high liver lipids levels, decreased glucose tolerance, insulin resistance and obesity. The mice fed a high-fat diet with naringenin maintained had a normal weight, normal triglycerides and cholesterol levels, normal insulin sensitivity and glucose metabolism.

At this time naringenin may have promise as a therapeutic treatment for metabolic syndrome.  The amount of naringenin used in the study was much higher then you would be able to get from eating fresh grapefruit. Experts are not yet sure if humans would have the same results as the mice did.  The next step is to check the feasibility of clinical trials on humans to test its safety and effectiveness.  Grapefruit and grapefruit juice need to be avoided with certain medications so speak with your pharmacist before adding grapefruit to your diet.

References

Metabolic Syndrome: http://www.ncbi.nlm.nih.gov/pubmedhealth/PMH0004546/

The effects of grapefruit on weight and insulin resistance: relationship to the metabolic syndrome:
http://www.ncbi.nlm.nih.gov/pubmed/16579728

Grapefruit Extract May Prevent Metabolic Syndrome:
http://www.nutraingredients.com/Research/Grapefruit-extract-may-prevent-metabolic-syndrome-Mouse-study

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