Sweet treats have appealed to human beings since time immemorial but with all our choices today, it’s easy to overindulge. Stevia, a natural zero-calorie sweetener, can keep your taste buds happy and help you stay in good shape.

The sweetener is made from the leaves of stevia rebaudiana, a plant that is native to South America but also grows in parts of Asia, including China. More than a thousand years ago, people in Paraguay used stevia much as we use sugar today, and as a medicine for digestive problems, mouth sores, and skin conditions.

Historically, the therapeutic effects came from drinking tea brewed with stevia leaves or from applying the herb to the skin. In studies, medicinal doses have lowered unhealthy levels of blood pressure and blood sugar, improved digestion, and inhibited the growth of harmful bacteria. (Stevia is found in some toothpastes and mouthwashes.)

Diabetes Implications

Although not conclusive, some studies have shown that as a sweetener, stevia may have a beneficial effect on blood sugar and blood pressure. It certainly doesn’t raise blood sugar, so it is a healthy option for people with diabetes or anyone who is trying to reduce his or her risk for the disease.

One study, published in the journal Appetite, compared the effects of stevia, aspartame (in NutraSweet and Equal), and sugar — used as sweeteners — on lean and obese people. Stevia was the only one that improved blood sugar and insulin function.

Where to Find Stevia

Until the latter part of 2008, stevia was available only as a dietary supplement in the United States because the FDA prohibited its sale as a sweetener. More recently, it has been approved as a food ingredient and is being added to more and more foods and drinks, sometimes in conjunction with other sweeteners to reduce overall calories.

Stevia is available in a variety of forms. Packets, generally equal to approximately two tablespoons of sugar, contain extracts of the leaves. The pure extract is most often combined with another ingredient as a bulking agent, because unadulterated stevia is 200 to 300 times as sweet as sugar and would be difficult to use in sufficiently tiny amounts. These are some popular brands:

SweetLeaf (www.sweetleaf.com): Packets and shakers contain an extract of the whole leaf, with more than 100 naturally present components, bulked with inulin, a healthy fiber found in fruits and vegetables. The extraction process uses only purified water and no chemicals. Liquid extracts, in water, come in a variety of flavors, including apricot nectar, cinnamon, chocolate raspberry, chocolate, English toffee, grape, lemon drop, peppermint, root beer, vanilla crème, and Valencia orange. Droppers make them easy to use.

Simply-Stevia (www.stevitastevia.com): Packets and jars of powder contain pure extract. Because there is no bulking agent, you may need to test with a toothpick to get a small enough amount to suit your taste. The company also makes fruit-flavored powders and flavored liquids, including chocolate, cognac, lemon, mango, orange, peach, peppermint, strawberry, toffee, and vanilla. Less concentrated versions, mixed with other plant-based sweeteners, are also available.

PureVia (www.purevia.com): Used in some PepsiCo products, PureVia is also available in packets. It contains a proprietary extract of one key component of stevia leaves, Reb A, and is combined with other natural sweeteners made from plant ingredients, cellulose, and natural flavors.

Truvia (www.truvia.com): Used by Coca-Cola in some of its products, Truvia contains rebiana, a sweetener derived from selected components of the stevia plant. It’s available in packets, and is mixed with another plant-based sweetener and natural flavors.

Product Pros and Cons

The normal taste of stevia is not the same as sugar. If you want to try it, which product works best depends on your taste buds and overall health goals.

PureVia and Truvia don’t contain extracts of the whole stevia plant and are designed to appeal to consumer taste buds that are accustomed to more traditional sweeteners. There is no evidence that these specific ingredients may have any health benefits beyond being calorie-free and not raising blood sugar.

SweetLeaf and Simply-Stevia contain dozens of additional elements found the stevia plant. Will they deliver more health benefits? There isn’t enough evidence to definitely say yes, but there’s a chance. And, if your personal preference is the most natural product you can find, these might appeal to you.

Flavored extracts of the whole stevia plant offer more possibilities in coffee, water, seltzer, smoothies, yogurt, and salad dressings that call for sugar. As an example, for a healthy version of a cream soda, try a combination of SweetLeaf root beer and vanilla crème in seltzer. Test first, starting with only a drop or two of each extract.

If you routinely drink soda or high-calorie coffee drinks, adding any flavored stevia to seltzer, water, bubbly mineral water or plain coffee could create a healthier alternative. Zero calories can pack a lot of flavor — naturally.