Citrus fruits and obesity

Weight loss benefits…

Citrus fruits include grapefruit, lemons, limes, tangerines, and oranges. They are best eaten fresh and are high in vitamin C as well as a wide range of nutrients and protective phyto-chemicals like pectin and naringenin. When eaten raw they are a good source of soluble and insoluble fiber. By adding Citrus Fruits to the daily diet, one can greatly increase metabolism, increase ability to get rid of fat and, hence, citrus fruits can be called as an effective weight-loss weapon.  It has been shown that people can actually eat large quantities of food without consuming too many calories by choosing foods high in fiber and water content. Besides being a refreshing source for the mind and body, citrus fruits have been also recognized for their numerous other health benefits.

How do citrus fruits help in weight loss?

According to researchers, Vitamin C & naringenin, found abundantly in all citrus fruits, have a fat burning quality.

Vitamin C

Vitamin C reduces the effectiveness of fat. It reduces its content and can liquefy or dilute fat. By diluting the fat, it makes it less effective, and easier to flush out of your system. Vitamin C also works on cholesterol deposits. Vitamin C can help burn out the cholesterol, hence, making it difficult for cholesterol deposits to form in blood vessels.

Naringenin – A phytonutrients present in citrus fruits

Citrus fruits mainly consist of various water-soluble plant pigments collectively called as flavonoids. Of all the flavonoids, the most abundant one is naringenin, a naturally occurring alkaline compound in all citrus fruit, but most significantly in grapefruit, orange and tomato.

Naringenin has a significantly positive bioactive effect on human health as a fat blaster (weight loss agent), antioxidant, anti-inflammatory agent, carbohydrate metabolism promoter and immunity system modulator. 

US study – Naringenin, a key to fighting obesity

In 2006, a scientific study was performed by the Florida Department of Citrus at the California Scripp's Clinic. It was found that by adding 4 ounces of grapefruit juice or half a grapefruit to meals, participants had an average weight loss of 3 1/2 pounds a week without altering their diet in any other way.  Researchers believed a compound, naringenin, in the grapefruit helped the liver lower cholesterol and also helped regulate insulin levels. Both of these factors had a significant impact on overall weight reduction of the subjects.

It should be noted that obesity constitutes the main part of the “metabolic syndrome” that is also characterized by hypertension, elevated blood cholesterol and disturbed glucose and insulin metabolism. 

Canadian study – Naringenin, as an effective weight reducer and maintainer

In another study performed at the Roberts Research Institute at the University of Western Ontario, the study mice were divided into four groups. They fed one group a normal, healthy diet. The second group received a high-fat, high-calorie diet. The third and fourth groups received a high-fat, high-calorie diet along with a naringenin supplement.

After just four weeks, the mice on the high-fat, high-calorie diet became obese. In addition, they became insulin and glucose intolerant. On the other hand, the two groups who received the naringenin supplement fared much better. Despite the same high-fat, high-calorie diet, these mice did not gain weight like their counterparts. In addition, the naringenin mice did not develop key health factors linked to Metabolic Syndrome. In fact, they lowered their triglyceride and cholesterol levels. They also continued to metabolize glucose normally and they never developed a resistance to insulin. At the end of the study, it was found that naringenin had marked lipid- and lipoprotein-lowering potential, without affecting caloric intake or fat absorption.

It was also found that naringenin, in concentrations far above levels found naturally, makes the liver burn fat instead of storing it. These effects were independent of caloric intake as 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.

As a conclusion, it was suggested that naringenin metabolizes hepatic VLDL (very low density lipoprotein) production, improves glucose tolerance and insulin sensitivity and prevents obesity associated with high-fat diet. 

(Mulvihill et al., Diabetes journal, July 10, 2009)