Dietary Fats and Heart Disease

A Supporting Role in a Big Event

Oct 31, 2008

Dietary cholesterol and saturated fats have been blamed for cardiovascular disease, but scientific evidence shows that other factors are involved.

In 1954, David Kritchevsky, a young Russian researcher claimed that adding cholesterol to a rabbit's diet caused atherosclerosis (deposition of fatty plaques in the arterial walls). His work was published in 1954 in the American Journal of Physiology. It piqued Ancel Keys' attention. After one study, Keys posited the "lipid" hypothesis. It suggested that there is a direct relationship between the amount of fat in the diet and heart disease. He advised that "reducing the amount of fat in your diet will lower your chances of heart disease," a link he could not prove in later studies. Keys said: "serum cholesterol is essentially independent of cholesterol intake over the whole range of the human diet."

Factors that Influence Heart Disease

Ongoing research uncovered key determinants that mediates the development of cardiovascular disorders. One of these pivotal elements is "heterozygous familial hypercholesterolemia," a genetic disorder caused by mutations on the "LDL receptor (LDLR)" or "apolipoprotein B (Apo B)". Apo B is the main lipoprotein that binds to a protein. LDLR receptors sit on the surface of many cells where they pick up circulating LDL particles in the bloodstream. They are plentiful in the liver where cholesterol is excreted through bile acids. Normal people have more LDLR receptors than hypercholesterolemic persons.

Men (older than 45 years) have higher risks of heart disease than women who develop cardiovascular problems by at least a decade; and age is also a factor. The longer a person lives, the more exposure he/she has to life's stresses.

Smokers have a higher risk than non-smokers. Smoking enhances inflammation, blood clotting, and constriction of blood vessels. Physical inactivity is a factor because it promotes weight gain that can lead to obesity. Obesity causes chronic inflammation, oxidative stress, DNA damage, and hypertension (HTN). Hypertension poses risks because it can injure the arterial wall(s) due to turbulent blood flow especially where the arteries branches.

Diabetes increases a person's heart disease risk. Insulin plays numerous physiological functions.

Deficits - as seen in type 1 or type 2 diabetes - can result in multiple metabolic dysfunctions like hyperglycemia (high blood glucose levels). Hyperglycemia destroys blood vessels through oxidative stress.

Saturated Fats, Trans Fats and Dietary Cholesterol

Not all saturated fats promote heart disease. Lauric and myristic acids are considered the most "cholesterolemic," while palmitic acid appears neutral. By comparison, trans fatty acids, (formed when liquid oil is hydogenated) mediates heart disease by constricting blood vessels leading to impaired blood flow. It also raises LDL cholesterol and reduces HDL cholesterol. And what about dietary cholesterol? Considering that almost 80% of the body's daily needs is synthesized by the liver, and dietary cholesterol contributes a mere 15-20% of the total requirements, its impact is minimal. However, because fats contain more calories than carbohydates or proteins, total daily fat intake should be minimized to avoid weight gain.

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The copyright of the article Dietary Fats and Heart Disease in Healthcare Research is owned by Alicia Richardson. Permission to republish Dietary Fats and Heart Disease in print or online must be granted by the author in writing.