If you're eating extra corn, fish and olive oil because you think they prevent heart attacks, you're taking in a lot of extra calories for the wrong reason. There is no scientific evidence that taking extra fat in any form prevents heart disease. The key to helping to prevent heart disease is to reduce intake of saturated fat.
No oil contains only one type of fat.
Corn oil is known primarily for its unsaturated fat content because it contains about 57 percent unsaturated fat, but it also contains about 29 percent monounsaturated fat and about 14 percent saturated fat.
Butter is known as a rich source of saturated fat content because it contains about 60 percent saturated fat, but it also contains about 37 percent monounsaturated fat and about 3 percent unsaturated fat.
Olive oil is known for its monounsaturated fat content because it contains about 51 percent monounsaturated fat, but it also contains about 28 percent saturated fat and about 21 percent unsaturated fat.
Butter is loaded with saturated fat, which raises blood cholesterol more than any other component in your diet. Margarine contains mostly polyunsaturated fats and should lower cholesterol, if it is substituted for butter.
However, polyunsaturated fats in margarine have a very short shelf life, so some manufacturers change the polyunsaturated fat in corn oil to partially hydrogenated trans fats. A recent article in the Journal of Lipid Research shows that trans fats in stick margarine raise cholesterol as much as the saturated fats in butter.
Substituting unsaturated fat for saturated fat can lower cholesterol. However, no one has shown that taking fish oil pills, olive oil or corn oil by themselves, without also reducing your intake of saturated fat, helps to prevent heart attacks.
Does chocolate cause acne?
Chocolate has not been shown to cause acne, tooth decay or obesity, and it's a good thing: Americans eat more than 2 million pounds of chocolate each year. However, chocolate is loaded with fat.
Studies at the University of Pennsylvania and in the United States Navy showed that chocolate does not cause acne. The fat in chocolate is broken down into the same fatty building blocks as fat from other foods. Then the oil glands in your skin pick up the fatty building blocks from the bloodstream and manufacture new oil. The oil on your face is manufactured in the oil glands and does not come from eating chocolate.
How can I be sure I'm getting enough protein if I eat mostly fruits, grains, vegetables and beans in a low-fat diet?
Americans get most of their protein from high-fat foods, such as meat and dairy products made from whole milk. When you go on a low-fat diet and eat fewer animal products, you should include a lot of beans to meet your protein needs.
You don't need much protein. You can get all that you need from beans, vegetables and grains. Frances Moore Lappe perpetuated a myth about protein requirements in her book, "Diet for a Small Planet." She incorrectly stated that people need to combine proteins at each meal. All protein is made up of building blocks called amino acids. They are strung together in chains to form the protein in your body. Of the 21 amino acids in your body, you need nine from your diet. The other 12 can be made from the essential nine, but you don't even need to get all of the essential nine at every meal. The proteins in your body release amino acids continuously into your bloodstream, so your blood is always loaded with the 21 amino acids and your body can use them to make all the protein that you need.
EDr. Mirkin is a practicing physician in Silver Spring specializing in sports medicine and nutrition.