I’ve noticed that the peanut butter I buy contains partially and fully hydrogenated oil. Does that mean it contains trans fat? —R.B., Brooklyn, N.Y.
Yes, but in amounts so small they’re insignificant. It’s true that partially hydrogenated vegetable oil—which manufacturers add to many peanut butters to keep them from separating—supplies trans fat, an especially unhealthy form of fat that may harm the heart, among other things, by raising bad (LDL) cholesterol and lowering good (HDL) cholesterol. (Fully hydrogenated oil, added for the same reason, does not contain trans fat.) But a U.S. Department of Agriculture analysis of 13 brands of peanut butter found that the amount of partially hydrogenated oil was so small that trans-fat levels weren’t even detectable. And there’s good reason to keep some peanut butter in your diet: About 80 percent of its fat is the healthful, mono- and polyunsaturated kind.
If you're trying to lower your cholesterol, take a look at our guide to fats in foods, find out which treatments are proven to work best (subscribers only), and read our free Best Buy Drugs report on cholesterol-lowering drugs.