Grapefruit contains a natural substance called naringenin that could protect people from the so-called metabolic syndrome. Metabolic syndrome includes the main risk factors for cardiovascular disease and diabetes, namely obesity, high blood pressure, problems with blood sugar levels and high cholesterol.
Autor: Dr. med. W. Tönnes
One grapefruit a day
Some earlier studies had already indicated that some components in the grapefruit fruit could have a positive influence on blood fat and blood sugar levels. For example, a study by Israeli researchers (Journal of Agricultural and Food Chemistry, 2006, Vol. 54, pp 1887-1892) showed that people who ate one pink grapefruit a day could reduce their cholesterol levels by 15 percent and their triglyceride levels by as much as 17 percent.
No problems with blood sugar and cholesterol
In the course of another study, researchers at the University of Western Ontario discovered that the flavonoid naringenin (a secondary plant compound), which is abundant in grapefruit, may have a similar effect on blood sugar levels as the hormone insulin.
Naringenin may therefore be able to compensate for the effects of insulin resistance and thus prevent diabetes.
The corresponding laboratory experiment also showed that naringenin prevents the liver from secreting low-density lipoproteins (those that carry the so-called bad LDL cholesterol through the body) and can consequently lower cholesterol levels.
In the latest study published in the journal Diabetes (monthly journal of the American Diabetes Association) ( 1 ), the same team of researchers conducted a follow-up study on this issue. Instead of cell culture experiments, they conducted experiments with mice – not with normal house mice, of course, but with special laboratory mice.
The animals had been genetically engineered to be born with a deficiency of low-density lipoprotein (LDL) receptors in their livers.
In a healthy body, the harmful LDL cholesterol is normally transported to the liver, where it is recognised by the LDL receptors, taken up into the liver cells, broken down and thus rendered harmless.
Since the poor laboratory mice are deprived of this possibility to break down the harmful LDL cholesterol, their cholesterol levels soon rose significantly. cholesterol levels rose significantly.
When the mice reached eight weeks of age, they were divided into four groups: The first group served as controls and received a normal diet. The second group was given a high-fat diet, the third group was given 1 percent naringenin in addition to the same high-fat diet, and the last group of mice was given a high-fat diet plus 3 percent naringenin.
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