Type of Dietary Fat Key to Heart Risk

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January 02, 2008 | 19,214 views

The value of hardened (trans) unsaturated fats in our food supply is probably best exemplified by the glazed doughnut. At room temperature, a glazed doughnut can be easily eaten with one hand, but warmed up it requires two hands and a napkin.

That's what trans fats can do for us: they keep our pastries firm and our margarine stiff at room temperature. Trans fats are generally found in absolutely unnecessary foods like doughnuts and margarines.

Trans fats are produced when polyunsaturated vegetable fats are artificially hydrogenated, a process that increases both their firmness and their resistance to oxidative spoilage. About 5 to 10 percent of the fat in our American diet and about 5 percent of the fat stored in our American adipose tissue is trans unsaturated fat

It is the type of dietary fat and not the total amount of fat consumed that affect a person's risk of coronary heart disease.

The findings may have an impact on current recommendations by United States health officials that the daily total dietary intake of fat in general not exceed 30% of total calories consumed.

This study focused on the cardiac risk of several types of fat: saturated fat, found in meats and dairy foods; trans unsaturated fat, the "hardened" fat found in margarine and fast foods; monounsaturated fat, as occurs in olive and canola oils; and polyunsaturated fat, as found in corn and soybean oils.

The main finding is that it's the type of fat that's most important for the risk of heart disease -- that it's not the total amount of fat because there are 'good' fats and 'bad' fats, much like 'good' cholesterol and 'bad' cholesterol. Higher intake of trans unsaturated fat is associated with increased risk of heart disease.

This is the first major epidemiologic study to look at all the major fats and total fats -- to put all the fats together in one prospective study. The researchers calculated a 17% greater risk of coronary disease from dietary saturated fat compared with the same caloric intake from carbohydrates.

BUT, trans unsaturated fats were associated with the highest heart risk -- almost twice that (93%) of carbohydrates.

This large effect is probably explained by the impact of trans unsaturated fat on blood lipid levels, its interference with fatty-acid metabolism, and its ability to elevate triglycerides -- a type of blood fat.

But the risk percentages of the other fats ran in the opposite direction. As compared with the equivalent energy intake from carbohydrates, the heart disease risk was 19% lower for monounsaturated fats and 38% lower for polyunsaturated fats among the nurses followed in the study.

In addition, the researchers note that the high-carbohydrate diet recommended by some heart disease prevention programs, which are intended to lower LDL ("bad") cholesterol levels also lower the ("good") HDL levels.

According to the report, replacing 5 percent of energy from saturated fat with unsaturated fat leads to a 42% lower risk of heart disease. And replacing 2 percent of energy formerly eaten in the form of trans unsaturated fat with unhydrogenated, unsaturated fat drops heart risk by 53%.

The New England Journal of Medicine ( November 20, 1997;337:1491-1499)

It is interesting to note that saturated fat has an increased risk of heart disease. This increase is small though. It is my belief that the risk is secondary to other factors. Generally saturated fat is from animal products that have been raised commercially.

This means the animals have been given estrogen and other hormones, antibiotics and fed grains that contain pesticides which bioaccumulate in the fat and are transferred directly to the individuals who eat them. They also eat large amounts of grain which does cause a shift in the percentage of saturated fat in their tissues.

I believe that if one eats animals fed organic food and large amounts of grasses rather than grains like corn and they are not given chemicals to enhance their growth their meat will have much lower levels of saturated fat and it will not be as harmful.

There is absolutely no question in my mind that butter is much healthier than margarine and healthy meat and poultry for most people will promote health rather than cause disease.

Organic eggs have far lower levels of saturated fat than non organic eggs. This is primarily due to the fact that the chickens are fed grains. Just as in humans, the grains and high carbohydrate diet will force the chickens to increase their insulin levels.

High levels of insulin will cause the liver to make saturated fats. This happens in chickens and humans and is one of the main reasons why carbohydrates like bread, pasta, cereal, fruit, rice, potatoes and cereals should be limited if one wants to avoid heart disease and cancer.

I find it fascinating that this study shows that even commercially raised sources of saturated fat only increased heart disease risk by 17% while the trans fat increased the risk by 93%.

The factor that is not reviewed in this report is the tremendous increase in cancer that occurs with trans fat ingestion that other studies clearly document

One must also be careful when using the other fats. I would not recommend most of the polyunsaturated fats. As mentioned last week, canola oil, although a monounsatrate should be avoided.

Most commercially available oils are highly processed and should not be consumed. The best oil would be extra virgin olive oil in glass.

The glass should be opaque or the bottle should be stored away from light to avoid any oxidation of the fats in the oil from light. Of course flax oil, if one can tolerate is one of the best polyunsaturated oils.

All corn and soy oils should be avoided and not consumed. For certain individuals sesame oil is excellent as it can inhibit the formation of arachidonic acid, which is a fat that is major precursor of inflammation.

Other oils, obtained from the health food store and cold pressed which might be useful are safflower, sunflower, almond, and organic peanut oil. Organic coconut oil would be the best oil to cook with as it is completely saturated and NO trans fats can be made from it.

There is a effort underway to have the government indicate the percentage of trans fat on the food labels. That measure will likely occur in the next few years. In the meantime it is relatively easy to avoid these incredibly dangerous poisons.

One just needs to search for the term partially hydrogenated oil on the list of ingredients as that will ALWAYS indicate trans fats are present in that food, the only question will be how much.

But there is no safe levels of the dangerous chemicals and they should all be avoided.