Garcinia Cambogia for Losing Weight

What is Garcinia cambogia?

Garcinia cambogia is also known as Garcinia gummi-gutta, Garcinia quaesita or Gambooge.

This is a subtropical variety of plants in the Garcinia species. It is native to Indonesia but it is also now grown in Southeast Asia as well as Central and West Africa.

Garcinia produces a pumpkin-shaped, thin-skinned yellow or green, or red fruit of varying sizes. The rinds of garcinia fruit are commonly used in the dishes and medicine of different Asian cultures. Both the fruit extract and dried rinds are used as sour curry condiments and to cure fish.

In traditional medicine, garcinia extract is used as a purgative. However, its inclusion in weight loss supplements is because of its ability to suppress appetite.

The main ingredient of garcinia extract is a compound known as HCA or hydroxycitric acid.

What is Hydroxycitric Acid?

Hydroxycitric acid is derived from citric acid. It is a naturally occurring phytochemical majorly found in garcinia and hibiscus.

Hydroxycitric acid is known to inhibit certain enzymes (such as citrate lyase) in the body. Other enzymes inhibited by hydroxycitric acid include alpha-amylase in the pancreas and alpha-glucosidase in the intestine. These enzymes are involved in carbohydrate metabolism and because hydroxycitric acid blocks their action, it is believed to contribute to weight loss.

While this effect has been demonstrated in vitro in the laboratory and animal models, human studies have not yielded the same positive results. Although the studies done with garcinia and involving humans have mixed results, the long-term use of this fruit in Ayurveda medicine is a testimony of its effectiveness as a weight loss herb.

Garcinia cambogia supplements are standardized by their hydroxycitric acid content. These supplements are available as tablets, capsules, and powders.

There are also proprietary formulations of hydroxycitric acid that are advertised to provide better bioavailability of the active ingredient. Hydroxycitric acid is also sometimes added to energy drinks and bars.

The typical dosage of hydroxycitric acid in achieving weight loss is 250 – 1000 mg taken 3 times daily.

How Garcinia cambogia promotes Weight Loss

There are 2 ways by which garcinia may promote weight loss: by suppressing appetite and by preventing the conversion of carbohydrate to fat as well as lipid metabolism. Both of these effects are attributed to hydroxycitric acid and they are linked together.

When garcinia blocks the enzyme, citrate lyase, it prevents the conversion of carbohydrates to stored fat. Instead, it encourages the burning of carbohydrates to generate energy immediately.

At the same time, garcinia pushes the liver to release more of its store of glycogen to be turned into glucose and energy. This sends a satiety signal to the brain that the body needs no more food. Therefore, one of how the herb works is through the suppression of appetite.

There is another important system of control for promoting weight loss. In obese individuals, carbohydrates and fats are quickly converted to cholesterol and triglycerides which are then stored up.  By blocking this storage, garcinia reduces the fat bulk responsible for most of the body’s excess weight.

Also by prompting the liver to release its store of glycogen, garcinia easily meets the body’s need for immediate energy without resorting to the ingestion of more calories from food sources.

Studies on Garcinia cambogia and Weight Loss

A 2005 study published in the journal, Food and Chemical Toxicology, investigated the efficacy and safety of a high dose of garcinia extract in producing weight loss in obese rats.

The study used 6-week old, male, obese, Zucker rats. These rats were divided into different diet groups according to the amount of hydroxycitric acid levels in their diets. The amounts of hydroxycitric acid given by groups are 0, 10, 51, 102, and 154 mmol per kg, and these were given for 93 days.

The results showed that the rats receiving 154 mmol of hydroxycitric acid per kg experienced the most significant suppression of epididymal (of the testes) fat accumulation. However, this dose (and the 102 mmol per kg) was also found to be toxic to the testes.

This study demonstrates the garcinia or its hydroxycitric acid extract is effective for inducing weight loss but the doses required for this effect must be well monitored because of the potential for toxicity.

Some experts have criticized the design of this study but the most important objection involved the contamination of the hydroxycitric acid used in the study. This is believed to be responsible for the observed testicular toxicity.

A 1996 study published in the International Journal of Obesity-related Metabolic Disorder involved 60 overweight volunteers some of whom were given 440 mg of hydroxycitric acid 3 times daily for 8 weeks.

This study found that the group of volunteers receiving hydroxycitric acid experienced significant weight loss compared to the placebo group.

However, a 1998 study found no such weight-loss benefits. In that study published in the Journal of the American Medical Association, 135 overweight volunteers were given either placebo or a garcinia extract containing 1500 mg hydroxycitric acid per day. Both of these groups of volunteers also received a low-calorie, high-fiber diet to prevent the accumulation of more fat weight.

The period of supplementation was 12 weeks during which the body weight and fat mass were measured.

The result of this study showed that both groups lost significant weight. However, there was no difference between the weight loss experienced by both the placebo and HCA groups.

The researchers concluded that the weight loss experienced was due to the low caloric diet and that garcinia or hydroxycitric acid failed to produce significant weight loss.

However, the researchers of this study have been criticized for using a high-fiber diet. It is well known that the high fiber content of the diet can inhibit the absorption of hydroxycitric acid.

In fact, in an earlier preclinical study, researchers established that hydroxycitric acid produces the most significant weight loss when combined with a diet rich in simple carbohydrates. Carbohydrates are likely essential for the optimal absorption of hydroxycitric acid.

Although laboratory and animal studies all suggest that hydroxycitric acid or garcinia extract is effective as a weight-loss supplement, there is no definite conclusion from human studies. This is mostly because both positive and negative studies are criticized for their poor designs.

Safety and Toxicity of Garcinia Extract

Garcinia is well tolerated at least for 12 weeks which is the average length of the longest clinical studies involving the herb.

Common side effects of this herb include headaches, nausea, and gastrointestinal discomfort.

Since there are no safety studies done on pregnant and breastfeeding women, garcinia is not recommended for these groups of users. Garcinia is also not recommended for use in children and by people with liver or kidney disease.

Most studies find garcinia quite safe and well-tolerated. In fact, long-term safety testing of a proprietary salt of hydroxycitric acid has been found quite safe. Still, a few cases of liver toxicity in one brand of hydroxycitric supplements have placed the medical community on alert for possible toxic reactions caused by garcinia.