Most Americans know that their diet influences their cholesterol levels. But with so many misconceptions, they might not know exactly how.
There is now conclusive proof that the right diet can slow or even modestly reverse the progression of atherosclerosis, which occurs when excess cholesterol accumulates along artery walls, hardens, and eventually narrows blood vessels. When a blood clot lodges in an artery narrowed by these fatty cholesterol deposits, blood supply is choked and a heart attack or stroke can result.
But understanding all the components of the "right" diet can sometimes be difficult. News reports don't always give the full story in a 10-second sound bite and, as a result, several misconceptions surround the many aspects of "heart-healthy" eating. Among them:
Misconception #1: Cholesterol-rich foods are the biggest contributor to high serum cholesterol.
While cholesterol-rich foods like eggs and shellfish can raise serum cholesterol levels and contribute to atherosclerosis, studies show that foods high in saturated fats are three to five times as powerful in raising blood cholesterol as cholesterol-rich foods.
Advice: Read food labels to know exactly how much saturated fat you're eating. No more than 10 percent of total calories should come from saturated fats — about 20 grams a day for someone consuming 2,000 calories. That's the amount you can get from two tablespoons of some salad dressings labeled "cholesterol-free." But many Americans get as many as 30 percent or more of their total calories from saturated fat food sources. While "light" and "low-fat" foods are usually a better choice, keep in mind that 2-percent milk and "light" cheeses still contain a considerable amount of saturated fat.
Misconception #2: All vegetable-based oils protect against heart disease.
All vegetable oils are a healthier alternative to butter and lard because they can be rich in polyunsaturated or monounsaturated fats — both of which can modestly lower cholesterol.
But all oils have about 120 calories per tablespoon and can contribute to weight gain.
In addition, studies indicate that normally heart-healthy vegetable oils like safflower and canola may be turned into an unhealthy fat when hydrogen is added to increase their chemical stability (and thereby enhance their potential for use in food products). This process, called "hydrogenation," transforms these liquid vegetable oils into a more solid and saturated form, known as trans fats.
Advice: Avoid eating trans fats completely. Don’t buy products that say "may contain hydrogenated or partially hydrogenated" oils. Also, deep-fried or processed foods such as french fries, doughnuts, pies and certain cakes usually contain a moderate amount of partially hydrogenated oils.
Misconception #3: Any dietary fiber can help lower cholesterol.
A high-fiber diet is important to overall health, but only one type of fiber can help lower cholesterol levels and it has only a modest effect.
Soluble fiber found in oat bran, certain types of beans, oranges, baked potatoes with skin and psyllium (the main component of Metamucil) can help lower cholesterol levels because it dissolves in water to form a gel that prevents cholesterol and fat molecules from being absorbed into the walls of the intestines and then the bloodstream.
Insoluble fiber found in wheat bran, vegetables and some cereals has no effect on cholesterol, but it may help with constipation.
Advice: Most Americans consume half the recommended amount of 25 grams of total dietary fiber each day. For help preventing heart disease, no less than 25 percent of that — or 6-1/2 grams — should come from soluble sources.
Misconception #4: You should drink at least two glasses of wine, beer or alcohol each day to lower your risk of heart disease.
Some studies show that moderate amounts of alcohol can reduce the risk of heart disease, because alcohol seems to raise the amount of HDL or "good" cholesterol. One to two drinks a day seems to be the right amount: more than that tends to raise triglycerides and has a lot of empty calories (those with no nutritional value). Alcohol is also a risk factor for high blood pressure.
Advice: If you don't drink, there is no need to start. If you drink, do it moderately. Although some studies show a beneficial effect from alcohol, drinking is still associated with an increased risk of other diseases, including some forms of cancer.
Misconception #5: Taking supplements containing the so-called "antioxidant" vitamins C and E have been shown to help lower cholesterol.
Vitamins C and E do not significantly affect cholesterol levels. In large well-designed studies, people taking vitamin C and E supplements do not show a consistent heart benefit.
Advice: For now, most experts recommend that people try to increase their intake of vitamins through better food choices and larger amounts of fruits and vegetables. Even though the results of anti-oxidant supplements have been disappointing, studies have consistently proven the benefits of a diet rich in vegetables and fruits.
