Breakfast may reduce morning heart risk.

Breakfast may reduce morning heart risk

Skipping breakfast may do more than cut time and calories from the morning routine. A preliminary study suggests people who shun breakfast, compared with those who enjoy a hearty repast, may spend their mornings at higher risk of heart problems, including heart attacks.

Since the mid-1980s, physicians have observed that heart attacks are most likely to occur within a few hours after waking. Although the phenomenon remains unexplained, researchers have proposed several early-morning physiologic changes as potential risk factors. Some point to increases in blood pressure or heart rate, while other studies hint that an increased tendency of blood platelets to clump or stick together when a person gets up in the morning may reduce blood flow in arteries already narrowed by atherosclerotic plaque (SN: 6/27/87, p.409).

Now, cardiologist Renata Cifkova reports data indicating that skipping breakfast may dramatically enhance the early-morning stickiness of platelets.

Cifkova, of Memorial University of Newfoundland in St. John's, says she happened upon this "accidental discovery" while planning a study to measure a protein marker of platelet activity -- blood stickiness or susceptibility to clotting -- in patients with high blood pressure. To validate an assay method, she first withdrew and analyzed blood from 20 healthy men and women.

During each of several visits, the healthy volunteers' blood levels of the marker protein, beta-thromboglobulin (beta-TG), averaged about 30 nanograms per milliliter -- except in two of the participants. These individuals showed a more than sevenfold increase in beta-TG on one morning. Upon questioning, each recalled only one unusual thing about the day on which their levels were high: no breakfast.

Intrigued by the possibility of a link between fasting and platelet stickiness, Cifkova initiated a small follow-up study, again using healthy volunteers. Between 10 a.m. and noon on two days no more than one week apart, she and her colleagues assayed beta-TG levels in 19 men and 10 women. Participants ate breakfast before coming in for the first test, but skipped it -- maintaining at least a 14-hour fast -- before the second test. After initial blood tests on that second day, the volunteers ate a meal. Three hours later, the researchers retested them.

Morning beta-TG levels averaged more than 2 1/2 times higher on the day the group skipped breakfast. After they ate, however, the protein plummeted to levels that "did not significantly differ" from those measured after breakfast on the first day, says Cifkova, who presented her findings last week in Washington, D.C., at the National Conference on Cholesterol and High Blood Pressure Control.

While conceding this study is far from conclusive, she says its results strongly suggest that "overnight fasting and skipping breakfast increases platelet activation and might contribute to the known increased frequency of [heart attacks], sudden death and ischemic stroke during early-morning and morning hours."

Noting that other studies have "indirectly suggested that platelets are an important contributing mechanism," cardiologist Syed M. Jafri says he has recently charted the daily cycle of changing platelet stickiness in nine healthy individuals and three people with chronic chest pain, or angina. He and his co-workers at the Henry Ford Hospital's Heart and Vascular Institute in Detroit tracked blood levels of beta-TG and another natural marker of platelet aggregation, called platelet factor 4.

Jafri says the findings, which he plans to present in Amsterdam this June at the International Congress on Thrombosis and Hemostasis, confirm what earlier studies had suggested: Platelet stickiness reaches a daily low overnight, then begins a steep climb when a person rises. Although reduced blood flow can result from activation of either platelets or a separate blood-coagulation system, Jafri's new data indicate that only platelet stickiness varies with the time of day.