FRIDAY, April 23, 2004 (HealthDayNews) -- A small study suggests that eating an oversized fast-food breakfast can stress blood vessels right up till lunchtime.
A 930-calorie meal consisting of an Egg McMuffin, a Sausage McMuffin and two McDonald's hash browns appears to trigger inflammation within arteries "within an hour," said study co-author Dr. Paresh Dandona, of the State University of New York at Buffalo. This inflammation "is slow to increase but it's not over by three hours. It's still continuing, and it might be continuing till four hours for all we know," he added.
The study appears in the April issue of the American Journal of Clinical Nutrition.
By now, most people know the regular consumption of high-fat, high-carbohydrate meals raises cholesterol levels and sends blood sugar rates soaring, raising risks for diabetes and cardiovascular disease.
But, according to Dandona, nutritionists are becoming increasingly aware that these types of meals can induce a third, equally dangerous response within blood vessels.
"We now believe that a common pathway for the causation of atherosclerosis -- hardening of the arteries -- is through inflammatory mechanisms," he explained. "Atherosclerosis is actually an inflammation of the wall of the arteries."
Certain types of nutrients, most notably fats and carbohydrate sugars, appear to induce the release of "free radical" molecules within blood cells, which in turn triggers inflammation, he said.
In their study, Dandona's team had nine healthy young adults consume a McDonald's meal consisting of an Egg McMuffin, a Sausage McMuffin and two hash browns, after an overnight fast. They then took blood samples from each of the participants one, two, and three hours after breakfast.
Study author Dr. Ahmad Aljada said the researchers chose the extra-large, two-McMuffin "double breakfast" because its 900 calories falls within the normal range for fast food meals, generally. Other studies are under way that focus on smaller (300-calorie) and larger (1,800-calorie) meals.
The researchers chose the McMuffin-hash brown meal because of its popularity, and said similar breakfast fare at other restaurants could provoke the same response.
Compared to individuals who had received no breakfast, those who had eaten the McDonald's meal displayed "evidence of free radical generation by the circulating white blood cells, which would cause inflammation within the white blood cells," Dandona said.
These markers of inflammation peaked at the second hour, but appeared at high levels in all three tests -- suggesting that high-fat, high-calorie foods might wreak havoc on arteries right up till the next meal.
Separate studies have suggested carbohydrates and fats are major culprits in inducing the inflammatory response, Dandona said, whereas proteins are relatively benign. Picking apart the McDonald's breakfast, the hash browns, cooking oil and muffin may be the main source of inflammatory stress -- not the protein-rich egg or sausage. Dandona theorized that "if you were to concentrate on proteins, you'd conserve your tissues while at the same time causing yourself the least amount of oxidative stress and inflammation."
But not everyone is convinced. Dr. Chris Rosenbloom, a professor of nutrition at Georgia State University in Atlanta, says she wouldn't make any dietary recommendations based on this small study. The study included only nine subjects and, because it included two McMuffin sandwiches, was "a pretty hefty breakfast," she pointed out.
"It would also have been more significant if they had compared the [McDonald's] meal to a 900-calorie meal of fruits and whole grain cereal, or lean meats or something like that," she said. "I would look at this as a preliminary study."
But Dandona's team said it has recently finished a separate study focused on just that type of low-fat, high-fiber meal. That study, as yet unpublished, found a 900-calorie breakfast consisting of fruit and high-fiber cereal "will not cause either oxidative stress or inflammation," Dandona said.
McDonald's announced last week that it was offering leaner fare on its menu, including low-carb alternatives, a wider variety of salads, bottled water, Happy Meals with apple slices, and even a pedometer to promote walking as a way of getting exercise.
Breakfast at McDonald's or other restaurants needn't be so calorie-laden. A meal of one Egg McMuffin and one hash brown clocks in at 430 calories, while other items, like sausage burritos and bagels, contain even fewer. At lunch or dinner, a Quarter Pounder with cheese and a small order of fries will add 760 calories.
Dandona believes the addition of foods rich in antioxidants might help "balance out" some of the negative effects of high-fat, high-carb meals. Orange juice, for example, is high in carbohydrates, "but doesn't give you any inflammation," because it's also high in free radical-busting antioxidants like vitamin C and flavonoids.
Vigorous exercise can also help reduce the bad effects of tasty but unhealthy foods, he notes. "Exercise does reduce the levels of inflammation," Dandona said. "How it does so, nobody knows, but there are good studies showing marathoners and ultra-marathoners -- folks running 100 kilometers -- that these guys have inflammation levels one-third of yours and mine."
The Buffalo researcher also stressed that fast-food chains are not the only source of artery-stressing breakfasts. Sit-down restaurants or even a home-cooked breakfast of eggs, bacon and toast would have the much the same effect on arteries.
Rosenbloom agreed. "The kinds of meals they used in this study are high in total fat, high in saturated fat, high in cholesterol and high in sodium," she said. "Those are all nutrients that we know are positively related to the development of cardiovascular disease."
McDonald's Corp. did not reply to requests for comment.
For advice on heart-healthy eating, check out the National Heart, Lung, and Blood Institute.