Week of 3/13/05

Dear EarthTalk: Are there any healthy alternatives to sugar?

—Andrew Young, New York, NY

Perhaps since the diet crazes of the 1970s, Americans have been looking to cut back on their intake of sugar. And doctors couldn't be happier, as they consider the prevalence of sugar in our society a root cause of numerous health problems, including the recent trends in obesity and adult onset diabetes.

By far the most commonly used sugar alternative today is aspartame. Most diet sodas contain aspartame, and it is the main ingredient in artificial sweeteners Equal and Nutrasweet, among others. But aspartame itself has been linked to a host of health problems, including Parkinson's disease, anxiety attacks, depression, and brain tumors. A recent report by the U.S. Department of Health and Human Services listed 90 documented symptoms associated with aspartame exposure. And according to the U.S. Food and Drug Administration (FDA), aspartame accounts for 75 percent of reported adverse reactions to food additives.

Honey, another popular sugar substitute, contains vitamins C, D, E and B-complex, as well as traces of amino acids, enzymes and minerals. However up to 50 percent of these nutrients are lost, unfortunately, when honey is commercially processed. Also, honey is high in calories and is absorbed by the body in much the same way sugar is, so it's not good a good choice if you are diabetic.

Luckily for those with cravings for sweets, several healthy alternatives to sugar do exist and can be found at most natural foods markets if not in mainstream supermarkets which increasingly have natural foods sections. For a taste similar to honey with fewer calories, agave nectar—made from the Mexican agave plant—is a good choice. Agave nectar is a fruit sugar, which absorbs more slowly into the bloodstream and is suitable for diabetics. It has a light, mild flavor with a thinner consistency than honey. One organic brand is Colibree. Another comes from Sweet Cactus Farms and can be ordered from their website online.

For baking, date sugar is a good alternative to conventional sugar. Actually consisting of finely ground dates, it contains all the fruit's nutrients and minerals. Date sugar isn't highly processed, and it can be used cup-for-cup as a replacement for white sugar. Also good for baking is xylitol, which sounds like a chemical but is actually birch sugar. Unlike conventional sugar, xylitol is actually reported to fight tooth decay, and has fewer calories. Both date sugar and xylitol are suitable for diabetics and others who are sugar sensitive.

Another sugar alternative—and one that has grown in popularity in recent years—is stevia, which comes from the stevia leaf in Paraguay. It is about 300 times as sweet as sugar, but has no calories. The FDA considers stevia a dietary supplement, because in its unprocessed form it is very nutritious, containing such vitamins as magnesium, niacin, potassium and vitamin C. But Japanese drink manufacturers have been using stevia as a sweetener for more than 30 years. Because stevia is so concentrated, it is best used as an additive to drinks, cereals or yogurts, and not for baking, as it doesn't have enough bulk.

CONTACTS: U.S. Food and Drug Administration, (888) INFO-FDA, www.fda.gov; Colibree, (866) 635-8854, www.agavenectar.com; Sweet Cactus Farms, (310) 733-4343, www.sweetcactusfarms.com.

Dear EarthTalk: What is "geothermal" heating and cooling, and how is it environmentally friendly?

—John Moran, Cranston, RI

Geothermal (sometimes called "geoexchange") heating and cooling is a technology that relies primarily on the Earth's natural thermal energy, a renewable resource, to heat or cool a house.

In winter or in colder climates, the Earth's natural heat is collected through a series of pipes, called a loop, installed underground or sometimes in a pond or lake. Water circulating in the loop carries the heat to the home where an indoor system using compressors and heat exchangers concentrates the Earth's energy and releases it inside the home at a higher temperature. In a typical system, duct fans distribute the heat to various rooms. These systems can also provide all or part of a household's hot water, according to the Geothermal Heat Pump Consortium, a trade organization.

In summer or in warmer climates, the process is reversed in order to cool the home. Excess heat is drawn from the home, expelled to the loop, and absorbed by the Earth. Thus the system is providing cooling in much the same way that a refrigerator keeps its contents cool—by drawing heat from the interior, not by injecting cold air from the exterior. The only additional energy that these systems need, other than the heat from the Earth's surface, is a small amount of electricity to power the pumps that circulate the collected heating or cooling throughout the home.

"It's a truly renewable system requiring a minimal amount of energy," says Lisa McArthur of the International Ground Source Heat Pump Association, another trade group. "The temperature underground is constant year round (low 40s in the northern U.S. to the low 70s in the South). If a home needs to be heated in the winter or cooled in the summer, the energy source is in one's own backyard," she says.

Depending upon the size and quantity of pumps needed, homeowners can expect to pay a few thousand dollars more for installation than for a conventional fossil-fuel system. But with geothermal, homeowners enjoy reduced energy bills, high reliability and long life. "There is always initial sticker shock, but our clientele is more concerned with the environment and long-term use rather than the initial bottom line," says Scott Jones, a sales manager at ECONAR, a Minnesota-based heat pump producer.

According to the U.S. Department of Energy, geothermal technology can reduce energy costs up to 60 percent compared to traditional furnaces. This means that a geothermal unit will pay for itself in two to 10 years. Subsidies and tax incentives, which vary from state to state, can make the systems even more affordable. Homeowners can check with the free online Database of State Incentives for Renewable Energy to see if their state provides any such incentives.

CONTACTS: Geothermal Heat Pump Consortium, (410) 953-7150, www.geoexchange.org; International Ground Source Heat Pump Association, www.igshpa.okstate.edu; ECONAR, (763) 241-3110, www.econar.com; Database of State Incentives for Renewable Energy (DSIRE), www.dsireusa.org.