The velvet bean, used for improving soil fertility, has been confirmed a possible treatment for male infertility.
Promoted by Kenya’s agriculture researchers as a fallow and green manure crop, the seeds of the climbing bean are sold in high end natural health products’ outlets in Nairobi.
For example, in Westlands, Nairobi, a bottle containing 90 capsules of velvet beans goes for Sh4,000 as a food supplement. Going by various brand names, the product is indicated to help in the production of the hormone dopamine, responsible for the feel good-mood.
Extracts from the bean are also extensively used to treat Parkinson disease - a long-term degenerative disorder of the central nervous system.
It has also been used in the Indian system of medicine called ayurvedic as a sex enhancer.
Though a prolific fodder, it is not good for non-ruminants such as humans due to its toxicity. But recently, a team of researchers from the University of Nairobi, International Livestock Research Institute and the Universite Evangelique en Afrique of DR Congo confirmed the plant to have fertility enhancement properties.
Scientifically, the plant known as Mucuna pruriens is a creeping vine and a native of Africa and Asia.
The research team had fed 24 male rabbits or bucks, on a meal containing small quantities of velvet bean seeds for three months. The bucks’ sexual behaviour, semen characteristics were closely monitored and recorded.
The study report published last Saturday in the journal Tropical Animal Health and Production says bucks fed on velvet bean seeds had increased successful mounting frequency by as much as 60 per cent. The feeding, the researchers say, had also positively increased the weight of testis in the rabbits by more than a third and that of the organ vas deferens by more than 50 per cent.
Vas deferens is a tube in male reproductive system that transports sperm cells from the manufacturing point to storage prior to ejaculation.
The team also reports improvement in sperm movement and concentrations, which are important for successful conception.
Feeding the rabbits with the mucuna seeds the report also shows to have dramatically improved the size and shape of sperms by over 60 per cent. These sperm characteristics are all important for conception, including in humans.
An earlier study on the causes of infertility among couples managed at the Kenyatta National Hospital showed more than half of male problems to come from abnormal sperm characteristics.
Normal sperm have an oval head with a long tail while a defective candidate is likely to have large or misshapen head, a crooked or double tail. In the KNH study, abnormal sperm characteristics were found in 52 per cent of males; 7.6 per cent with no sperm in ejaculate and 14.6 per cent with erectile dysfunction.
This meant slightly more than half of the male partners had abnormal sperm characteristics, reported the study by Dr Charles Otwori.
The study found 41.8 per cent of infertility to be due to female factor only; 16.5 per cent male factor only and 35.4 per cent due to both while 6.3 per cent of cases were not explained.
However, nationally it is estimated approximately 35 per cent of cases of infertility are a female factor, 30 per cent a male factor, 20 per cent both parties and 15 per cent of cases not diagnosed.
Mucuna is a common weed growing in most warm and humid parts of the country and abundant at the Coast and western Kenya.
However, it has been extensively promoted as a fodder and green manure by the Kenya Agricultural & Livestock Research Organisation.
Areas of promotion include the Coast and Western Kenya in Vihiga, Trans Nzoia and Kitale and specifically among small scale dairy and maize farmers.
At Western Cosmetics & Supplements in Westlands, Nairobi the velvet bean product goes by the name Dopa Mucuna and only available to adults.
“It is good for any adult at any age especially those who want to enjoy life with a significant spoon,” said an attendant at the outlet.
But she was quick to clarify it is neither a medicine nor registered as such but is known to increase the feel-good hormone called dopamine. Dopamine has also been called the happiness tree.
“It is good especially as Valentine approaches,” said Mr James Kithure with a wink. Kithure was purchasing some products including mucuna at the outlet.