Low Carb Diets May Hurt Heart Health

Millions of Americans who are faithful to low-carbohydrate regimens to lose weight are missing out on fiber-rich foods essential to healthy hearts, experts warn.

"By eating a low-carbohydrate diet, you are selecting out those foods that may be rich in healthy carbohydrates," said Jeannie Moloo, a Roseville, Calif., dietitian and a spokeswoman for the American Dietetic Association. She said these nutrient-packed foods "lower LDL, the bad cholesterol, and blood insulin levels. They may also reduce blood clots."

Weight-conscious individuals continue to turn to low-carb regimens to trim waistlines. But according to nutritionists such as Moloo, they're forgetting that not all carbohydrates are created equal.

"First, there's refined carbohydrates -- that's where the nutrition has been removed and [manufacturers] have sometimes added sugar to the product -- foods like white rice, white bread, cookies," Moloo said, adding she has no problem with dieters cutting out these carbs.

"Refined carbohydrates release their sugar quickly into the blood, causing a dramatic spike in insulin," she said. They are the "worst offenders" in terms of raising risks for cardiovascular disease.

On the other hand, there are the "good carbs" -- foods such as fruits, vegetables and, especially, whole grains -- all packed with micronutrients, minerals, antioxidants and fiber.

In one recent study, involving data on the diets of more than 350,000 men and women, researchers found that, for every 10 grams of cereal fiber consumed daily, risks for death from heart disease dropped by 25 percent.

Fiber is simply the undigested part of any food, and it can come in a water-soluble or water-insoluble form.

"When it comes to preventing heart disease, the water-soluble form is the one that's been shown to lower cholesterol levels," Moloo said. "However, the water-insoluble form is important, too, because it may help slow down the digestive process, thereby lowering blood sugar and insulin levels."

And there's more to fiber-rich foods such as whole grains than just fiber. "The bran and the germ contain fiber, vitamins, thiamine, niacin, riboflavin, various minerals, vitamins and antioxidants," said Katharine Tallmadge, a Washington, D.C., dietitian and a spokeswoman for the American Dietetic Association.

"In fact, researchers haven't really figured out if it's the fiber or these other phytochemicals that pass on these health benefits," she said.

Daily servings of good carbohydrates are crucial to maintaining a healthy cardiovascular system, Tallmadge said, but separating the good from the bad at the supermarket isn't always so easy.

"It's tricky, because a lot of breads, for example, are called '7-Grain Bread,' 'Whole Wheat Bread,' 'Oat Bread,' etc. But if you look on the ingredient list and the first ingredient is 'wheat flour,' that does not mean whole wheat," she said. Instead, stick to breads where the first ingredient clearly reads whole wheat, Tallmadge said.

The "Nutrition Facts" panel gives another clue to whether a cereal, bread, cracker or other product is truly high in nutritious fiber. "Look at the dietary fiber line on the Nutrition Facts label and select a bread that has at least 3 grams of fiber per serving," Moloo said.

There's less guesswork with the amount of fiber found in fruits and vegetables. "Fresh, frozen or canned fruits and vegetables, it's pretty much going to be the same," Tallmadge said.

The bottom line, according to both experts, is that by ignoring fiber-rich foods, individuals on low-carb diets aren't doing their hearts any favors. "They are eating a very unhealthy diet, and that's a tragedy," Tallmadge said.

Popping a fiber supplement won't change that, she added. "Because it isn't just the fiber that helps us -- it's fiber-rich foods. In fact, when they isolate fiber and study it separately, they don't get the same [heart-healthy] result."