When you're watching your diet, you don't need to avoid the tasty olive. As a topping to liven up a pasta dish, a luscious tapenade or just eaten whole, olives contain some essential nutrients and will help keep your heart healthy. They're not a perfect food, however, so you will have to enjoy your olives in moderation.
In its natural state, the olive is a bitter, inedible fruit. Processing, such as curing or fermentation, removes the bitterness. All the olives you see in stores--green, black, red and other varieties--stem from the same basic fruit and get their color depending on how long they ripen and the treatment method. Generally, ripe, black olives cured in water with sea salt maintain their nutrition the best. Most canned olives are less nutritious, particularly canned black olives, which usually get their color from processing, not ripening.
The George Mateljan Foundation lists olives as a good source of iron, vitamin E, dietary fiber and copper. A cup of olives, about 134.4 g and just more than 150 calories, contains 4.44 mg of iron, 4.03 mg of vitamin E, 4.3 g of dietary fiber and 0.34 mg of copper. It's also a good source of monounsaturated fat. Other nutrients in olives, in lesser levels, include vitamin C, vitamin K and protein.
When you add olives to your diet, you promote healthy cells, reduce your risk of heart disease and help keep your digestive system in good shape, according to the George Mateljan Foundation. Vitamin E blocks damaging substances called free radicals from your cells, and it also helps your body form red blood cells. Free radicals also can build up in arteries and lead to a heart attack or stroke, and they also can cause cells in your digestive tract to mutate into cancer. The fiber in olives also helps keep cholesterol low.
Olives also come packed with something you'll want to limit in your diet: sodium. A cup of olives contains almost 1,200 mg of sodium, just under half the amount you should allot yourself in a day. High-sodium diets can lead to high blood pressure and raise your risk of stroke. Additionally, even though olives contain the healthy form of fat, too much will affect your weight. So, although adding a smattering of olives to your diet will bring health benefits, you should eat them in moderation.
Olives supply an even bigger part of a healthful diet through the oil obtained from them. Like the olive itself, olive oil contains monounsaturated fat that helps promote healthy cholesterol levels and prevent heart disease, according to Mayo Clinic nutritionist Katherine Zeratsky. Substituting olive oil for saturated fats such as butter and animal fats lowers your risk of heart disease. The healthiest forms of olive oil are the extra-virgin and virgin forms, which undergo the least amount of processing.