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STEROLS/STEROLINS: MARKETING HYPE OR SCIENCE?
Prof. Patrick JD Bouic
Professor: Chief Specialist Scientist,
Head: Immunology
Faculty of Health Sciences, University of Stellenbosch
There has appeared in the press over the last few years numerous reports written about the wonders of the plant sterols and sterolins
(Moducare™) as natural immune boosters. Articles have ranged from mere journalistic reports to cures being claimed with the use of this supplement. We have been involved with the research behind the development of these natural molecules and we would hereby like to provide an overview of the workings of this product on the immune system.
The sterols and sterolins are the 'cholesterol' of all higher plants and we as humans ingest these through our diets. The molecules were discovered as far back as 1922 but were never considered to have important biological activities until it was realized that due to the similarity in structure between the cholesterol and sterol molecules that the latter could be used to block the uptake of dietary cholesterol in individuals with raised plasma levels of cholesterol. We have seen in recent years the appearance of sterol-enriched margarines punted as cholesterol lowering foods.
How do the sterols and sterolins impact on the immune cells?
The immune system is literally a system made of a network of cells and the factors that they secrete. Such factors are called cytokines and these have the most profound impact on the outcome of an antigenic stimulus. In health, there exists a balance between cytokines that enhance the formation of antibodies by B-lymphocytes and others that promote a cellular response (conducted by T lymphocytes) such as when we are infected by a virus. However, certain infections and diseases lead to an imbalance between these cytokines so that we have an overwhelming cellular or antibody response. ModucareTM has been shown to promote the secretion of cytokines leading to cellular responses, hence making it useful in diseases where we need to boost this side of the
immunity. Such infections would include viral and intracellular bacterial
infections.
Clinical studies conducted using ModucareTM:
Several studies have been undertaken using this natural immune modulator. We have concentrated on the infectious diseases since these are the most relevant in South Africa. Studies include:
· Role of the sterol/sterolin mixture as adjuvants in the treatment of pulmonary
tuberculosis.
· Ability of the mixture to prevent post-event immune suppression in marathon
runners.
· Long term immunological effects in HIV infected patients
· Open labelled study of the effects on symptoms in chronic rhinitis/conjunctivitis patients.
New studies have been undertaken to test the effects of this natural product in chronic diseases. These studies include the anti-inflammatory effects in rheumatoid arthritis patients and its role in the management of Hepatitis C carriers: we await the outcome of these shortly. In parallel to our HIV studies, we have used the same compounds in FIV infected domestic
cats: this serves as a model of the retroviral disease that affects millions of patients in South Africa.
How then can simple plant derived compounds be so important in the functioning of the immune system? The answer lies in the fact that these molecules (together with other minerals and nutrients) are removed from our daily diets by refinement processes. Although the natural sources of the sterols/sterolins are nuts, seeds and oils, these are removed to prevent their precipitation upon storage. Over the ages, we have become a society of fast foods and refined nutrition and our diets have possibly become devoid of important nutrients. After all, the incidence of cancer and other chronic diseases are diseases of First World societies. Is this due to our nutritional intake? The sterols/sterolins were discovered in 1922 and are the 'Cinderella's' of nutrition: they have important roles to play in the way the immune system functions and could possibly have a major impact on the way of managing chronic conditions. After all, was it not Hippocrates who said 'Let food be our medicine'!
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