Sterols, Sterolins and Digestive Enzymes
Interview with Prof. Karl Pegel
Natal University, Durban
What is your professional background and research experiences on Plant Sterols/Sterolins?
I am a chemist at heart. My love for chemistry started at school in former South West Africa - now Namibia. I did my chemistry studies and my Ph.D. at the Witwatersrand University, Johannesburg, and joined the Natal University/Chemistry department afterwards where I became Professor of Chemistry and worked until I retired at the end of 1991 and now continue as an Honorary Research Associate.
How did you get involved with the sterol/sterolin research?
The whole story started in 1968 when Mr. Liebenberg contacted me to investigate a plant which was used to treat benign prostatic hypertrophy. The Hypoxis plant was used by some South African people to treat this infliction and Mr. Liebenberg wanted to know if we could find out the chemical spectrum of that plant and I started to investigate it in 1968. During the course of this investigation we isolated sitosterol glucoside which we had tested clinically and was found to be active.
We then synthesized sitosterol glucosides, formulated it and supplied it to various people particularly in old age homes; and they all improved. We then made contact with a company in Germany and they marketed it under the name of Harzol.
Within a very short period of time Harzol became a market leader for treatment of that specific ailment. This would not have happened if the patients and the urologists who treated them did not see some benefit.
What is sterolin actually?
The plant sterols including sitosterol are the cholesterol of plants i.e. plant fats. Every plant makes plant sterols like all humans and animals make cholesterol. Sterolins are the glucoside molecules of plant sterols. In our opinion and in everybody else's opinion at that stage sitosterol was thought to be inactive.
The only use of sitosterol at that time was to suppress high cholesterol levels and it was thought that this happened because the sitosterol interfered with the absorption of cholesterol.
Why are plant sterols/sterolins so important for the human health and how do they work?
In 1986 and thereafter we investigated the problem of the assumed inactivity of plant sterol a little bit more and we found that sitosterol had actually an effect on the immune system. Now this research was done at the University of Stellenbosch under the direction of Prof. Patrick Bouic and he also found that sitosterol glucoside had an effect on the immune system by stimulating the formation of T-cells.
The ratio of sitosterolin to sitosterol in those tests ranged from 1:1 to 1:500. The combination of plant sterols and sterolins was more effective than that of the components individually, so there was a synergistic effect.
Though both substances are effective in themselves, but together they are even better. Both of them probably have a different effect, but these effects work together. We are not quite sure how either substance works but there is quite a lot of research going on at the moment.
Has the plant sterol/sterolin ratio any effect on the efficiency of the treatment?
In Harzol we had a ratio of 100 parts of sitosterol to 1 part of sterolin. There was a very good reason why this was done at the beginning as we wanted to hide the sterolin known to be the active part of the sterols.
But if one looks at the ratios in nature in the plants this is more like one molecule of the glucoside to 5 to 10 molecules of sitosterol. This in my opinion is a much better ratio. So plant sterols and sterolins you get from the plant extract would be a more natural one.
What other benefits are known and are there any side effects?
There are no known negative side effects from the intake of plant sterol/sterolin supplements - they are an integral part of all fresh and unrefined plant foods. Perhaps I should explain here that if we talk about plant sterols it is never a pure compound; the plant sterols are always a mixture consisting of sitosterol, campasterol, stigmasterol and others and from these it is sitosterol which is biologically the most effective one.
As quite a number of diseases are related to immune system dysfunctions sitosterol and its glucoside have also got a beneficial effect on cancer prevention, rheumatoid arthritis etc., and it has been known for a long time that sitosterol and sitosterolin have got a mild anti-cancer effect but not sufficiently strong for a big pharmaceutical company to show enough interest. In my opinion it is more a preventative - it is certainly not effective when the cancer already exists in an advanced stage.
But in order to prevent cancer formation sitosterols and sterolins are very essential. It is not a drug that will somehow kill tumors or cancers but by stimulating the immune system it will improve the quality of life of a cancer patient.
There is also evidence that it alleviates the ill-effects of chemotherapy. It makes the life of such patients more bearable. Plant sterols/sterolins also seem to be very effective in the treatment of rheumatoid arthritis. I can only say that some people respond very well but others do not since the disease is due to many different causes.
As far as HIV infected patients are concerned the clinical trials done in Stellenbosch have shown that most of these people have benefited - even though there is not any evidence that it will cure HIV infection. But the patient will be able to cope better with the infection and not proceed from HIV infection to fully blown AIDS.
Have you used plant sterol/sterolins personally? If so, to what effect?
Yes, I took the sitosterol/sitosterolin supplements since 1972 and am enjoying good health and enough energy to continue with my research.
Do you take any other supplements in addition to the sterol/sterolin products?
One must of course realize that plant sterols/sterolins are not the answer to all ailments in life. Vitamin C and E (perhaps) but certainly Magnesium are just as important supplements. They are essential ingredients to keep the machinery working.