The Impact of Long Term Consumption of Khat on Public Health

The Problem

The cultivation and consumption of the stimulant leaf khat (Catha edulis Forsk) is widespread in several countries of East Africa and the Arabian Peninsula. Khat has other names and spellings: qat, kat, chat, quat, catha, tschat, miraa, African salad, African tea, Abyssinian tea, kuses-salahin, and tohai. The leave comes from a small evergreen shrub that can grow to tree size.

Khat was originated in Ethiopia and spread through Kenya, Somalia, Djibouti, Uganda, Tanzania, Zimbabwe, Zambia, South Africa, and Yemen. Young buds and tender leaves are chewed to attain a state of euphoria and stimulation. Although khat is freely possessed in these regions, its use in the western countries such as the United Kingdom, Canada, and the United States has been restricted recently, and it is now classified as a controlled substance. Nonetheless, people from these regions continue their habit of chewing Khat even after migrating to the Western countries. The habit of chewing khat has expanded to the western world because:
1) A significant number of people from developing countries have migrated to the western countries, including individuals from khat cultivating regions and brought with them their habit; and,
2) Khat can be easily transported to western countries where large number of immigrants from the Horn of Africa and the Arabian Peninsula live.

The international organizations were confronted with the problems associated with khat as early as 1935. Significant efforts and progress have been made since then in understanding the pharmacology of khat. The World Health Organization played an important role early on in encouraging and funding scientific studies designed to understand the active constituents of khat and health problems associated with its use. Because of their efforts, we now understand the pharmacology of khat and the health and human problems that follow. 

The Purpose

The purpose of this review is to describe briefly the adverse consequences of habitual khat chewing on public health and to educate the general public on the issue. According to P. Kalix of the University of Geneva (1991, 1992), khat leaves contain cathinone, an active brain stimulant that is similar in structure and pharmacological activity to amphetamine. Like amphetamines, khat ingestion results in decreased appetite, euphoria, increased intellectual efficiency, and hyperalertness. 

The overlapping effects of khat and amphetamine suggest that they stimulate the central nervous system through similar mechanism(s). Khat leaves must be chewed fresh for the strongest effect, and freshness can be prolonged for a couple of days with refrigeration. Chronic use of khat produces undesirable side effects, including sleeplessness, nervousness, impotence, loss of appetite, constipation, and nightmares. 

Soon after chewing, khat can cause dizziness, rapid heartbeat, and pain in the upper abdomen. These unpleasant feelings are gradually replaced by bliss, euphoria and pleasant energetic pleasant feelings. Prolonged anorexia associated with khat use leads to malnutrition and increased susceptibility to infectious diseases such as tuberculosis. 

Nasher and Associates (1995) found that khat chewing inhibits urine flow, an effect caused by blood vessel constriction which also causes erectile dysfunction. Furthermore, epidemiological and experimental studies suggest that long term use of khat causes reproductive toxicity. In addition to the neurological effects, consumption of khat is also associated with reproduction problems in men and women and in laboratory animals.

In controlled studies using Yemeni male volunteers, el-Shoura and Associates of the King Saud University (1995) clearly showed that heavy use of khat causes decreased semen volume, sperm count, and sperm motility, and it increases the number of sperm that appear abnormal under the microscope. Interestingly, previous studies reported by Islam and Associates of the King Saud University (1990) demonstrate that male rats respond similarly to the men, but other effects can be measured in rats that cannot be ethically learned from men. Rats treated with the active constituent, cathinone, had testicles, epididymides, and seminal vesicles that were smaller, and they had lower levels of testosterone in their blood. Examining testicles through the microscope, pathologists could see degenerative changes in the cell that produce testosterone and in Sertoli cells, the cells that support sperm production. 

In women and female laboratory animals, khat causes other undesirable effects. Recently, Islam and Associates of the King Saud University reported (1994) that female rats given extract from khat leaves from day 6 to 15 of their 21-day pregnancies ate less and gained less weight. While that sounds like a good thing to women in industrialized countries, the treatment also increased the number of rats that died while still in the uterus, and, in the smaller litter size.

Reports by Jansson and Associates of Gothenburg University (1988a, 1988b) show that female guinea pigs similarly also had smaller pups, and this was shown to be due to decreased blood flow to the uterus. Eriksson and Associate of Karolinska Institute (1991) also reported similar effects that babies born to women who chew khat habitually are smaller and their mothers produce less milk. Clearly, their mother's use of khat retards their development, and this retardation is likely to have long term consequences. Female rats and guinea pigs apparently respond to khat a lot like people do. Based on the above mentioned and other studies, the observed adverse effects of khat on the male and female reproductive tracts should be viewed as a serious concern for the public health. 

While many effects of khat are of consequence only or primarily to the user, the increased susceptibility to infectious disease and the threats to normal development of the children of the chronic users are public health concerns. Furthermore, as the tolerance of drug use among employers drops to zero, khat users will find themselves closed off to many best jobs. Thus, because of unemployment and low-paying jobs, khat use will damage the financial status of individuals, families, and communities. While more research is always desirable to better understand the small details, we know enough now to say clearly that the use of khat should be discouraged. 

Selected References

el-Shoura SM, Abdel Aziz M, Ali ME, el-Said MM, Ali KZ, Kemeir MA, Raoof AM, Allam M, Elmalik EM. Deleterious effects of khat addiction on semen parameters and sperm ultrastructure, Human Reproduction, 10(9):2295-2300, 1995.

Eriksson M, Ghani NA, Kristiansson B. Khat-chewing during pregnancy-effect upon the off-spring and some characteristics of the chewers. East Africa Medical Journal, 68(2):106-111, 1991.

Islam MW, al-Shabanah OA, al-Harbi MM, al-Gharably N.M. Evaluation of teratogenic potential of khat (Catha edulis Forsk.) in rats. Drug Chemical Toxicology 17(1):51-68, 1994.

Islam MW, Tariq M, Ageel AM, el-Feraly FS, al-Meshal IA, Ashraf I., An evaluation of the male reproductive toxicity of cathinone. Toxicology. 16;60(3):223-234, 1990.

Jansson T, Kristiansson B, Qirbi A., Effect of khat on uteroplacental blood flow in awake, chronically catheterized, late-pregnant guinea pigs, Journal of Ethnopharmacology, 23(1):19-26, 1988a.

Jansson T; Kristiansson B; Qirbi A. Effect of khat on maternal food intake, maternal weight gain and fetal growth in the late-pregnant guinea pig. Journal of Ethnopharmacology, 23(1):11-17, 1988b.

Kalix P. The pharmacology of psychoactive alkaloids from ephedra and catha. Journal of Ethnopharmacology, 32(1-3):201-208, 1991.
Kalix P. Cathinone, a natural amphetamine. Pharmacological Toxicology 70(2):77-86, 1992.

Nasher AA, Qirbi AA, Ghafoor MA, Catterall A, Thompson A, Ramsay JW, Murray-Lyon IM. Khat chewing and bladder neck dysfunction. A randomized controlled trial of alpha 1-adrenergic blockade. Br J Urol. 75(5):597-5988, 1995.

Abraham Dalu, Ph.D. 

Citation format

Dalu, Abraham. 2000. The Impact of Long Term Consumption of Khat on Public Health. The Sidama Concern Vol.5. No.4, pp.15-16. [on-line] <http://www.sidamaconcern.com/articles/abraham.htm>