Sterolin

What's in a name?

Names of anything tell a story, so let me begin the story of sterolin by telling you how it has that name.

Chemists name molecules according to their general structure. For example, all bioflavonoids share a certain backbone structure of carbon rings and so belong to the family of flavonoids.

Another group of chemical compounds sharing a name and a common backbone structure of carbon rings are the sterols. One particular sterol is plentiful in bile. The Latin term for the gallbladder and the bile collection system involves the root word chole- so this sterol found in the bile is given the name chole-sterol or cholesterol.

Later on, of course, cholesterol was discovered in the blood and found to be related to heart disease. If you're a frequent reader of these handouts, you'll know that cholesterol is also found in large amounts in the membranes of the brain. Is required for the formation of other hormones with names like pregnenolone and DHEA, as well as the stress hormone cortisol and the sex hormones testosterone, progesterone and the estrogens. All these hormones have a similar backbone structure of carbon rings and belong to a subclass of sterols call steroids.

Whereas animals make and use cholesterol, plants do not. Plants use what are called phytosterols, the most abundant of which is sitosterol. This sitosterol can be attached to a carbohydrate compound and is then called sterolin. These, of course, are very important to the function of the plant. We animals have become accustomed over the long stretch of time to getting this steady source of sterols in our diet and using them to the benefit of the our immune system.

Dietary sterols

You will probably not be surprised to learn that the processed modern diet is low in the sterols. A diet rich in unprocessed plant foods will supply 200-300 mg of sterols. If, however, the diet is rich in processed food and animal food the intake might be as low as 40 mg a day. Some vegetarians will eat a good deal of refined flour and other processed food and even though they are vegetarian they may have intakes of less than 100 mg a day. Sterols, present in vegetables and fruits, are particularly rich in seeds including cereals and legumes.

Three ounces of whole-wheat berries will contain about 4200 mg of sterols. Make it into flour and it will lose almost 90% of that.

Sterols, it turns out, appear in many of our medicinal plants, including

• Serenoa repens (saw palmetto) for benign prostatic hypertrophy
• Pygeum africanum for benign prostatic hypertrophy
• Silybum marianum (milk thistle) for liver problems
• Ginkgo biloba for memory and circulation

Sterols have been shown to be part of the active portion of ginseng, both Panax ginseng and Eleutherococcus. So it may be that the sterols in some medicinal plants are responsible in all or in part for some of the medicinal value of those plants.

Sterols and the immune system

Different sterols influence the immune system differently. We just mentioned that cortisol, one of the major stress hormones, is derived from cholesterol. In some ways, it impairs the efficiency of the immune system as it fights stress. In other ways, it can help.  Plant sterols, on the other hand, have been shown in every study done on them to enhance immune function.

The lympocytes are white blood cells. There are different kinds of them, responsible for several aspects of the immune response.

When the T-helper cells are stuck in an unhelpful response to a viral infection, a response with too much T-helper2 activity, sterols can correct this imbalance. They help the T-helper1 cells produce more interferon to fight colds (and other viruses such as HIV and hepatitis C) which helps turn off the allergy-promoting T-helper2 cells. This is discussed in the Lancet 1989 (#8644 pg 943).

A typical supplement capsule might contain 20 mg of plant sterols and 200 mcg of plant sterolins per capsule. This is the identical substance used in the studies above. The usual dose is 1 capsule three times a day for three to six months.

Why take sterols?

Plant sterols appear to exert their benefit in the same way that vitamin C, vitamin E, beta-carotene and other plant nutrients are helpful. That is, they act by enhancing physiological functions of which they have been a part for all of our evolutionary history. By taking increased amounts in supplement form, we can compensate for relative deficiencies in our diet. We can also perhaps raise them to values slightly higher that what we might otherwise obtain and in this way attain a more optimally functioning physiology. Because this is the way in which plant sterols work, I would suggest using them for at least two or three months to see what the effect would be. In the study with benign prostatic hypertrophy and tuberculosis for instance, the study ran for six months. Is clear from the study on runners that a matter of weeks is all it takes to show a change in the functioning of the cortisol stress response system and in the immune functions associated with that. But if you're going to try it for a prostate problem or arthritis or for some general decline in immune function, it will take somewhat longer for you to see an effect on your day to day life.

Side Effects

Very high doses of sterols have been reported to cause occasional constipation or diarrhea. High doses have also been shown to reduce cholesterol. In the other studies I mention above, no side effects from the use of sterols were reported.