Katuk, Sauropus androgynous, has become one of my favorite vegetables for hot, humid climates. It has a pleasant peanut-like taste when eaten raw and the cooked leaves taste excellent as spinach. The plant is sold everywhere in Malaysia and nearby countries, where it is grown as an edible hedge. Malaysian scientists have developed a technique for forcing the shoot tips to grow extra long and tender by applying plenty of manure, water and (sometimes) shade. The 5-inch (13 cm) shoot tips (locally called “sayor manis”) are sold to upscale restaurants locally and also exported to Japan, and possibly elsewhere, as “tropical asparagus.” I ate sayor manis in a hotel in Malaysia and it was outstanding. The chef stir-fried it for one minute.
In 16 years of growing katuk in southwest Florida, we have never had a serious disease or insect problem during the hot rainy season when most temperate vegetables do not survive. In our cooler winter, however, when we are enjoying temperate vegetables, katuk essentially goes dormant. At that point leaves may be damaged by disease or insects.
ECHO has never featured katuk in EDN, in spite of its excellent qualities, because we have only been able to propagate it by cuttings, and they have not survived simulated overseas mailings. Occasionally we do get seed, but it does not seem to retain its viability for long (not surprising for a plant native to a rainforest region). If you would like to be placed on a waiting list to receive seed when our plants produce again (realizing we can make no guarantees of viability), please write to ECHO. If you will be visiting ECHO sometime we can give you a plant or cutting.
We were quite surprised when Yang Wang, a citizen of Taiwan, wrote us after an internet search for information about katuk led him to ECHO’s web site. In Taiwan there have been several cases of irreversible lung damage that have been traced to use of katuk. How could a common vegetable in Malaysia be harmful in Taiwan? We have not been able to get the kind of details we would like, but apparently the health problem is caused by special circumstances. It appears that katuk was used in Taiwan as part of a dieting program. Dieters ate leaves raw; probably in large quantity. We do not know whether they ate anything else with the katuk. We asked Mr. Wang for more details. He could only add that he heard that in the Taiwan dieting method dieters drank raw juice made from katuk leaves. I believe they may have consumed very large quantities and thus concentrated a harmful substance in the juice they were drinking.
I spent a summer working under Dr. Peter Van Soest in the animal sciences department at Cornell University. He said that one “should learn a lesson from the deer.” A deer will eat plants that can kill cattle. How? Deer are browsers. They will eat a little of something they like, but then go on to look for something else. Grazing cattle, on the other hand, sometimes “founder” or are poisoned by eating one type of plant in large quantity. Goats are probably in the same class as deer. Dr. Van Soest pointed out that the liver can detoxify small amounts of most poisons in food. Large amounts overwhelm this ability. This is a compelling reason for diversity in diet. I find so many applications of this principle as we work with different foods at ECHO that it has become a standing joke among the staff. It could be that in the case of katuk, we need to “take a lesson from the deer,” and enjoy it in small quantities.
An article in the American Journal of Epidemiology (May 1, 1997 - Volume 145, 842-9) states that, “In late April 1995, an outbreak of a poorly defined respiratory illness related to the ingestion of leaves of Sauropus androgynus was observed in southern Taiwan. To further evaluate the association between S. androgynus and bronchiolitis obliterans syndrome, a hospital-based case-control study was conducted with one case group and three different control groups at Veterans General Hospital-Kaohsiung …. A total of 54 cases (50 females, 4 males), 54 age- and sex- matched neighborhood controls, 54 matched routine physical check-up controls, and 54 matched self-referred patron controls (who had ingested S. androgynus yet without obstructive physiology) were interviewed for clinical symptoms, history of S. androgynus consumption, and potential confounding factors. All 54 cases (100%) ingested S. androgynus compared with only five (9%) neighborhood controls.” Their statistical analyses showed that the lung problems were related to consumption of large quantities [4.5 kg (10 lbs. versus 0.4-2.0 kg (0.9-4.4 lbs.) in controls] and drinking raw katuk juice rather than stir-fried or boiled leaves.
What is our conclusion? We still highly recommend katuk as a quality vegetable for the hot, humid tropics. Just learn a lesson from the deer.