Catha Edulis: Physiological effects

Last modified: Thursday, 25. December 2008 - 9:40 am

In one study on a group of 80 healthy volunteers, researchers found that during a three-hour period of chewing fresh khat leaves, there was a significant progressive rise in blood pressure and heart rate even one hour after chewing had ceased. These reactions were due to the stimulant effects of the drug.

Additional physiologic effects reported with khat use include:

• dizziness

• lassitude

• stomach pain

• thirst

• dilated pupils (mydriasis)

• anorexia

• constipation

• impotence

• insomnia

• thirst

The unpleasant side effects of khat, especially the insomnia, have led some users to seek counteracting agents such as tranquilizers and alcohol — substances that are particularly hazardous in combination with khat.

Harmful side effects

In one study, 44 species of fungus were isolated from 30 samples of khat leaves gathered in Yemen. Researchers considered the toxins found in some of these species a threat to public health.

In addition, to ward off a wide range of insects, diseases, and weeds — and to preserve an important cash crop — toxic chemicals are often used to spray the plants. When the leaves are chewed, these toxins enter the bloodstream, causing potential health problems, including chemical hepatitis.

The overall effect of khat on patients with diabetes is harmful. The anorectic effect of khat leads to skipping meals; also, users are less likely to follow dietary advice, and consuming sweet beverages with khat aggravates hyperglycemia (high blood sugar levels). The anorectic nature of khat largely explains the malnutrition often seen in habitual khat users.

Some researchers believe that there is not a high potential for khat abuse because the volume of leaves required limits the ingestion and absorption of a large amount of the active ingredients. Yet the effects of khat have been difficult to quantify. The leaves are a non-standardized material, and their potency depends on freshness and place of origin. Yet although there is no known record of khat resulting in overdose, adverse side effects are somewhat greater in children, in those over 55 years of age, and in those who use large quantities of the substance for extended periods of time.

Long-term health effects

Because khat is chewed for the most part, medical problems associated with the oral cavity and digestive tract are common and may lead to inflammation and secondary infections. There is also some evidence of increased risk of oral cancer.

In a 1995 study published by the British Journal of Urology, researchers found that khat chewing inhibits urine flow, an effect caused by blood vessel constriction, which also causes erectile dysfunction. This constriction also affects blood pressure and heart rate; however, further studies are needed to determine the possible long-term cardiovascular damage associated with regular khat use.

Several studies suggest that long-term khat use causes reproductive toxicity. In addition to neurological effects — damage to the nervous and respiratory system have been documented — khat consumption is also associated with reproductive problems in men and women. Heavy use of khat is associated with decreased semen volume, sperm count, and sperm motility, and with an increased number of sperm appearing microscopically abnormal.

Women who chewed khat gained less weight during their pregnancies, and blood flow to the uterus was decreased, retarding fetal development and resulting in low-birth weight babies with a greater potential for medical problems. Mothers also produced less milk. These adverse effects are considered a serous public health concern by some researchers.

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