Tall oil' pine used to reduce cholesterol

By JOE SCHWARCZ, Freelance November 27, 2010
 
The tanker trucks roll into the giant Arboris chemical plant in Savannah filled with "tall oil," a smelly yellow-black liquid.
 
It's a curious name for the muck and has nothing to do with height. "Tall oil" is a bizarre anglicization of the Swedish word "tallolja" meaning "pine oil," tracing back to a time when coniferous trees were the source of pulp for the "kraft" papermaking process.
 
This process -"kraft" derives for the German for "strong" -involves digesting wood pulp with sodium sulphite and sodium hydroxide, leaving "tall oil" behind as a residue.
 
Chemically the oil is a very complex mixture, but thanks to ingenious processing, trucks leave Arboris carrying commercially important substances such as turpentine and sterols.
 
Turpentine finds uses as a solvent, but what is to become of the sterols?
 
Some are used as intermediates to produce a variety of drugs, including estrogen for hormone replacement therapy and corticosteroids for the treatment of arthritis. But the bulk of the sterols are converted into "sterol esters." And what is their fate?
 
Believe it or not, after being incorporated into an expanding array of "nutraceutical" foods, their final destination is our digestive tract!
 
Nutraceuticals are foods designed to have health effects beyond fulfilling the body's nutritional needs.
 
In this case, the desired effect is a lowering of blood cholesterol, the substance that by its very mention can strike fear into many a heart. Even people who are not quite sure what cholesterol is, or what it does, want to have less of it cruising around their bloodstream.
 
That's because the message has been very effectively delivered: High blood cholesterol is a risk factor for heart disease.
 
Indeed, cholesterol is found at the scene of a crime, if that crime is the triggering of a heart attack by a blood clot that chokes off the flow of blood through a coronary artery. Since the blood delivers oxygen needed for cellular functions, the potentially devastating result of such a blockage is the death of heart cells from oxygen starvation.
 
But what does cholesterol have to do with this? After all, it isn't a chemical monster.
 
In fact, we couldn't live without cholesterol. It is an essential component of cell membranes, and is also the raw material our body uses to make essential compounds like the sex hormones. And who would want to be without those?
 
So cholesterol, per se, is not the problem. But cholesterol in the wrong place at the wrong time is.
 
Here is the crux of the matter. A blood clot can form when a deposit, called a plaque, builds up inside the wall of a coronary artery, stretching the tissue enough to cause a rupture.
 
The body's defences perceive this as an injury and proceed to repair the tissue damage by forming a clot, just as is the case when we cut ourselves.
 
But, of course, inside a coronary artery a blood clot is a problem, especially if that artery has been narrowed by extensive plaque formation.
 
And guess what is in the plaque? Along with fats and calcium, it's cholesterol.
 
How did it get there? From too much circulating around the bloodstream, often as a result of a poor diet.
 
Estimates are that roughly half the adult population has higher than desirable cholesterol levels, a condition that shows no symptoms.
 
Most of our cholesterol is synthesized in the liver, but some originates from eating animal foods.
 
Animals, like us, make cholesterol since it is an essential biochemical for them as well.
 
Plants, on the other hand, do not produce any, but they do make closely related compounds called sterols and stanols. Because of their chemical similarity to cholesterol, it turns out that sterols and stanols can compete with cholesterol for attachment to transport molecules that ferry cholesterol from the gut into the bloodstream.
 
As a result, less cholesterol is absorbed from the digestive tract and blood levels drop.
 
Sterols and stanols are found in a wide variety of foods, with whole grains leading the way.
 
But the total amount consumed in the average daily diet is only about 300 mg, not enough to significantly reduce blood cholesterol.
 
Numerous studies have shown that for an appreciable impact, a daily dose of roughly two to three grams is needed. That can lower blood cholesterol by as much as 14 per cent, a drop capable of significantly reducing the risk of heart disease.
 
The reduction is even greater when combined with statin therapy.
 
Since obtaining two grams of sterols and stanols from the diet is not possible, a whole industry based on fortifying various foods with these compounds has arisen.
 
Industrially, sterols can be isolated from soy, corn or most efficiently from "tall oil," and can then be blended into various foods.
 
The problem, though, is that the sterols alter the texture and consistency of the product often in a way as to make consumer acceptance unlikely.
 
However, if the sterols are reacted with fatty acids such as oleic acid derived from canola oil, the "sterol esters" so formed can be readily incorporated into foods ranging from margarine and yogurt to chocolate and crackers. Four tablespoons of fortified margarine a day can deliver two grams of sterols, but that's a lot of margarine.
 
The same amount of sterols, however, can be found in two 100 gram servings of fortified yogurt.
 
But is there a downside to pumping sterol esters into our bodies?
 
After all, such amounts do not occur in foods naturally. The answer, according to the long-term clinical studies, is no. But interestingly, there is no benefit from consuming more than three grams a day either.
 
Let's remember, though, that high cholesterol is only one risk factor for heart disease, and we are talking here only about a modest reduction in that risk, and only with regular daily consumption of sterol esters. The major emphasis still has to be on exercise coupled with an overall healthy diet. But in addition to that, there's no harm in "pine-ing" for a little lower cholesterol.