Why is saturated fat bad for heart health?

Dr. Michael Roizen, MD
Internal Medicine
No food element has been more closely linked to arterial aging than saturated fats and their cousins, trans fats. This relationship was confirmed by a twenty-five-year study that evaluated the development of coronary heart disease and the long-term risk of death. Studies have repeatedly found a strong correlation between cardiovascular disease and the consumption of saturated fats.

Apparently, saturated and trans fats increase inflammation of the blood vessels. They turn on certain genes that produce proteins associated with inflammation of blood vessels. Foods high in saturated fats promote plaque buildup along the artery wall, which is the first stage of cardiovascular disease and arterial aging. In addition, saturated fats facilitate the mechanism that increases low-density lipoprotein (LDL) cholesterol in the bloodstream.
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Saturated fats raise cholesterol levels more than anything else in your diet. Saturated fats are found in high fat and processed meats (prime or rib cuts, variety luncheon meats -- bologna, salami, etc., pepperoni, bacon, sausage, hot dogs) and high fat dairy products (whole or 2% milk, cheese and full fat yogurt, ice cream), butter and tropical oils (palm, palm kernel and coconut). LDL (bad) cholesterol can be reduced 8-10% by reducing saturated fat to 7% of daily caloric intake or 12-18 grams daily. Read Nutrition Facts on food labels (when available) to determine saturated fat content.
Rebecca S. Reeves
Nutrition & Dietetics
Can reducing saturated fat in the diet lower a person's risk of heart disease? A review article including 21 studies found no significant association between saturated fat intake and the risk of heart disease.

In considering the results of this article, it must be remembered that all the studies were observational, meaning results of clinical trials in which persons were actually placed on different diets were not included. It was also suggested that persons substituted simple, probably processed, carbohydrates for the saturated fat.

There is good evidence that replacing saturated fat with polyunsaturated fat is associated with decreased risk of coronary heart disease so the message should be to replace saturated fat with foods containing unsaturated fat like vegetable oils, fish, nuts and seeds.
Robert  Davis, PhD
Health Education
The main sources of saturated fat include meat, whole milk, cream and lard. Experiments performed a century ago found that saturated fat can cause heart disease in animals. Early studies also showed it to raise cholesterol levels in people.

However, it was the work of scientist Ancel Keys that really put the issue of fat and heart disease on the map. Beginning in the 1950s, he observed that men in countries with the highest intake of saturated fat had the highest heart-related death rates, while populations with the lowest intake had the lowest death rates. Keys's population studies were capable of showing only correlation, not cause and effect. To get more definitive evidence, scientists have performed dozens of additional studies over the decades. Surprisingly, despite all the dire warnings about the dangers of saturated fat, research as a whole has failed to prove that eating less of it reduces the risk of heart disease.

While some cohort studies have found a link between saturated fat and heart disease, many others have not. When researchers pooled data from 21 of these studies, they found no evidence of an association. Results from randomized trials have been similarly mixed. One possible reason is that there are different types of saturated fat, which can have different effects. Certain kinds, such as stearic acid (which is found in high amounts in beef and chocolate), do not raise cholesterol levels. Others do, but they may boost HDL (or good) cholesterol along with the bad kind (LDL), perhaps minimizing any harmful effects.

Another explanation for this big fat scientific mess is that when you eat less saturated fat, you eat more of something else -- and not all substitutions are the same. Clinical trials show that replacing saturated with polyunsaturated fats, such as those found in nuts, fish, and vegetable oils (like safflower or corn oil), reduces the risk of heart disease.

But swapping saturated fats for refined carbohydrates like lowfat cookies or white bread may not be any better for your heart and could even be worse, according to research. Trans fats are an especially bad alternative.
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Part II: Part I answers "Why is saturated fat bad for you?" This is a continuation of that answer:

What does it mean?

Succinctly put: we eat too much meat: beef, steak, pepperoni, sausage, bacon, pork, lamb, ham, salami, hot dogs, butter, cheese, ice cream etc. Take a look at these figures:
  • The average intake of meat in the U.S. in 2002 was 200 pounds per person, 23 pounds higher than in 1970
  • American’s eat on average 33 pounds of cheese a year
  • In 2004 Americans consumed over 1.3 million pounds of butter
Our bodies are not designed to handle such titanic amounts of saturated fat, processed or red meat. Our bodies do not know we can order pizza 24/7 or go to a store filled with food any time we want. Our bodies still believe we need to run out each morning and catch breakfast. Thus drowning our systems with animal foods day after day leads to physiological dysfunction and disease.

Scientists have not pin pointed a single cause because there are probably a myriad of biochemical reasons why the human body cannot tolerate a constant assault of bad fat and meat. Some mechanisms have been identified for example, how saturated fat depresses LDL (bad) cholesterol receptors on hepatic and other cells leading to an increase in serum cholesterol. But there is much to be done in the scientific arena.

In the meantime, cut back on your intake of meat and other animal foods. Start experimenting with beans, soy, nuts and nut butters such as peanut, almond and cashew butter, and low or non-fat dairy (low or non-fat means much of the saturated fat has been removed). There are many delicious, easy to make vegetarian dishes including vegetarian chili, pasta primavera, veggie burgers, hummus in pita with chopped cukes & tomatoes, edamame, vegetable succotash and hearty lentil soup. Do your body a favor by going meatless and cheeseless at least a few days a week. Chances are you will lose pounds, gain energy and feel great. Your body will thank you year after healthy year.

To see the references and the article in its entirety go to:,_Nutrition_%26_Wellness/Samanthas_Blog/Entries/2010/10/10_Is_Red_Meat_Really_Bad_for_You_.html
Emilia Klapp
Nutrition & Dietetics
Saturated fat plays a major role in causing heart attacks because it is hard to dissolve. It can cause the arteries to get clogged, preventing the blood from circulating freely. It is found mostly in animal fats and foods such as butter, whole milk, cheese, sour cream, and whole yogurt. It also causes the liver to overproduce cholesterol. Limit your intake to less than 10% of the total calories you ingest daily.

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Important: This content reflects information from various individuals and organizations and may offer alternative or opposing points of view. It should not be used for medical advice, diagnosis or treatment. As always, you should consult with your healthcare provider about your specific health needs.