This article, focusing on pistachios and pecans, is the first partof a continuing series on the health benefits of nuts.

PISTACHIOS

Why: Even as a kid I loved pistachios. Unfortunately, I loved them too much. They offer good levels of protein and fiber along with dense levels of eight nutrients and are the lowest in calories and fat of any nut. Also, if you buy them in the shell, you'll eat them more slowly, allowing time for the "fullness" factor to kick in.

Nutrients: In addition to providing dense levels of seven essential nutrients (thiamin, vitamin B6, copper, manganese, potassium, phosphorus and magnesium), pistachios offer a good source of fiber and are the only nuts that contain high levels of lutein and zeaxanthin, antioxidants needed to maintain eye health. In fact, a 1-ounce serving of pistachios has 20 percent of the daily recommended value for vitamin B6 (equal to two servings of avocado), more antioxidants than 1 cup of green tea, more lutein than three medium tangerines or a glass of orange juice and 3 grams of dietary fiber, about the same amount as a serving of oatmeal.

Health perks: A few ounces of pistachios a day can lower bad cholesterol and increase good cholesterol levels. A recent study published in the Journal of the American College of Nutrition found that for people with moderately high cholesterol levels, a daily diet consisting of 15 percent of calories from pistachios (about 2 to 3 ounces or one to two handfuls of kernels) over a four-week period lowered some blood lipid levels. High levels of most blood lipids increase the risk of developing both heart disease and stroke, while lowering blood lipid levels has been shown to reduce the risk. Also, among nuts, pistachios offer some of the highest levels of phytosterols, a plant sterol shown to reduce cholesterol absorption from other foods.

According to a study conducted at the University of Toronto, pistachios, when eaten with some common high-carbohydrate foods, may actually slow the absorption of carbohydrates into the body, resulting in a lower-than-expected blood sugar level.

Nutrition stats: (1 ounce, about 50 pistachios without shells): 158 calories, 12.6 grams fat, 7.93g carbs, 2.9g fiber, 5.84g protein.

Purchasing: Look for pistachios with green kernels and smooth, creamy shells, and make sure the shells are partially open.

Storage: They can get stale fast (absorbing water like a sponge) and lose that fantastic crunch. Keep them fresh by placing them in a dry place in some type of airtight container or plastic-zipping bag — or freeze them.

PECANS

Why: They taste a bit like walnuts and can be eaten spiced, in a pie, in a nut mix and on their own. Their delicate, tender texture and full flavor make pecans compatible with a broad range of foods.

Nutrients: Pecans contain more than 19 vitamins and minerals — including vitamin A, vitamin E, folic acid, calcium, magnesium, phosphorus, potassium, several B vitamins and zinc. One ounce of pecans provides 10 percent of the recommended daily value for fiber, and they are also a high-quality source of protein.

Health perks: Research published in the Journal of Agriculture and Food Chemistry found that pecans rank highest among nuts and are in the top category of foods with relation to antioxidant capacity. Just last year, findings from a study published in Nutrition Research showed that eating about a handful of pecans each day may help reduce the risk of heart disease. The researchers suggest that this positive effect is in part due to the pecan's significant content of vitamin E, a naturally occurring nutrient that protects blood lipids from oxidation. When "bad" (LDL) cholesterol is oxidized, it is more likely to build up and result in clogged arteries.

Also, in 2001, a study published in the Journal of Nutrition found that eating pecans may have cholesterol-lowering benefits similar to those of cholesterol-lowering medications. Other studies have shown that eating pecans may help reduce the risk of gallstones, aid in weight loss and support prostate health.

Nutrition stats: (1 ounce, 19 halves) 196 calories, 20.4g fat, 3.93g carbs, 2.7g fiber, 2.6g protein.

Purchasing: The nuts with the largest kernels and good color are considered highest quality.

Storage: Pecans should be protected from moisture, light, heat and oxygen. Storing in-shell pecans in a cool, dry place will preserve freshness for several months. In-shell or shelled, pecans can be refrigerated for about nine months or frozen at 0 degrees Fahrenheit for up to two years. They can be thawed and refrozen repeatedly without loss of flavor or texture. After removal from cold storage, the quality remains good for about two months.

Charles Stuart Platkin is a nutrition and public-health advocate, and author of "Breaking the FAT Pattern" (Plume, 2006). Sign up for the free Diet Detective newsletter at www.dietdetective.com.