I have struggled with sugar for most of my life. My mom recalls finding candy wrappers under my bed when I was a kid. I’d think nothing of devouring a whole bag of candy corn around this time of year.

These days my sweet tooth has morphed into a wine tooth; most of the sugar I consume comes from sauvignon blanc, and the thought of eating candy corn sets my teeth on edge.

But for all my interest in sugar, and despite my being a nutrition writer, I’ve never really known much about sugar as a nutrient. With Halloween — one of sugar’s high holidays — coming up, I figured this was a good time to get the scoop on sugar.

We need some sugar. In the form of glucose, sugar provides the fuel our cells, especially those in our brain, need to function. But most of our sugar should come from food sources such as fruits and whole grains, says Christine Gerbstadt, a spokeswoman for the American Dietetic Association and author of “Doctor’s Detox Diet: The Ultimate Weight Loss Prescription” (Nutronics 2011).

Consistently eating too much sugar can, over time, lead to cardiovascular trouble. “Sugar influences blood release of fat or lipids,” Gerbstadt says. Eating a diet high in sugar increases the risk of developing high levels of triglycerides, the “fluffy fat” that can get caught up in arteries and form plaques or globules of fat, she says. When those plaques break loose and travel to the heart, brain or kidney, they can cause heart attacks, strokes or kidney failure, Gerbstadt says.

Especially problematic are the “added” sugars: caloric sweeteners that are added to baked goods, soda and, of course, candy. According to the 2010 Dietary Guidelines for Americans, added sugars include high fructose corn syrup, white sugar, brown sugar, corn syrup, corn syrup solids, raw sugar, malt syrup, maple syrup, pancake syrup, fructose sweetener, liquid fructose, honey, molasses, anhydrous dextrose and crystal dextrose. The American Heart Association recommends that added sugars should add up to no more than 5 percent of our daily calories. For someone on a 2,000-calorie daily diet, that equals 100 calories (about 25 grams or 6 teaspoons). It’s hard to keep track, though, because the Food and Drug Administration doesn’t require labels to list added sugars separately from naturally occurring ones.

There are also misconceptions about sweets. “Sugar, by itself, does not cause diabetes,” says Stephanie Dunbar, director of clinical affairs for the American Diabetes Association.

Gerbstadt agrees. She says that by virtue of candy’s high calorie content, overindulging on it can make us overweight; being overweight is in turn a risk factor for cardiovascular disease and diabetes.

Another misconception is that candy is the main culprit. The dietary guidelines note that nearly 36 percent of our added sugars come from sodas, energy drinks and sports drinks, while only 6 percent come from candy.

Still, sugar is okay in moderation: “It’s not a health food,” Dunbar says. “But a little bit is not going to hurt you.”