For many people, an irregular heartbeat is just an annoyance, but certain arrhythmias may have serious consequences, ranging from fainting to sudden death. In fact, in Westernised industrial societies, sudden cardiac death accounts for about half of the total coronary deaths rate (Nutr Rev, 1993; 51: 271-3). Research has shown that certain dietary factors may affect the regularity of the heartbeat.
* Cut down on caffeine. Caffeine is a stimulant and, according to the director of the Office of Toxicological Sciences of the US Food and Drug Administration, 'there are clearly people who have serious cardiac arrhythmias due to caffeine consumption' (FDA Consumer, 12/87-1/88). In one study, 12 heart patients who usually drank three to five cups of coffee a day were kept off coffee for two days, then given the caffeine equivalent of two cups. Both before and after caffeine, they received cardiac stimulation, which produces arrhythmias in those prone to them. Before caffeine administration, only one person had a rapid heartbeat. After the caffeine, eight patients developed an arrhythmia (N Engl J Med, 1983; 308: 814-6).
While these results are consistent with earlier work (J Chron Dis, 1980; 33: 67-72), more recent studies suggest that the evidence is not so clear-cut (Heart, 1996; 76: 355-7; Ann Intern Med, 1991; 114: 147-50). It may be that different hearts react differently to caffeine. So the best way to find out of caffeine is affecting your heart is to stop ingesting it and see what happens.
* Watch your alcohol intake. The evidence that a high alcohol intake causes arrhythmias is more consistent. Heavy drinkers are more than twice as likely to develop arrhythmias than those who average less than one drink a day. Alcohol abuse gradually damages the heart, and atrial fibrillation (chaotic quivering of the heart) may be the first sign of heart damage (Arch Intern Med, 1991; 151: 36-42). Arrhythmias are an important reason why alcoholics face an increased risk of sudden death, a risk that peaks at about age 50 (JAMA, 1990; 264: 377-81). Similarly, high blood alcohol levels have been linked to irregular ventricular contractions (Am Heart J, 1985; 110: 961-5).
* Increase beneficial fats. The source, rather than the amount, of dietary fat has a considerable influence on heart rhythms. Animal studies have found that when the heart is stressed by drugs, emotions or a diminished blood supply, diets rich in saturated fatty acids render the heart more vulnerable to potentially fatal arrhythmias. But diets rich in polyunsaturated fatty acids reduce this risk. This finding is consistent with the results of a human study which found higher levels of saturated fatty acids in the fat tissue of heart attack victims who had serious ventricular arrhythmias than in those without such arrhythmias (Am J Cardiol, 1989; 63: 269-72).
While oils rich in monounsaturates (such as olive oil) may help prevent atherosclerosis, recent studies have found them to act like saturated fatty acids in weakening the heart's ability to maintain a normal rhythm under stress (Prog Lipid Res, 1994; 33: 355-85). So, consider boosting your intake of polyunsaturated fats, particularly the omega-3 family, which provide superior protection against arrhythmias (Nutrition, 1994; 10: 161-9).
Researchers in Denmark investigated the effects of dietary omega-3 on arrhythmias and the heart's ability to adjust heart rate to the body's needs in 55 patients who had had a previous heart attack. Heart rate was monitored at the beginning and end of the study. Participants were randomly assigned to receive either 5.2 g of omega-3 fatty acids daily or placebo. At the end of 12 weeks, there was a slight decrease in arrhythmias in the treated group compared with the controls, but heart rate control was significantly increased with omega-3 supplementation compared with the placebo (Ugeskr Laeger, 1997; 159: 5525-9).
* Take extra nutrients. Magnesium supplementation in magnesium-deficient patients taking digoxin for arrhythmia allowed their drug doses to be halved (Am J Cardiol 1986; 57: 956). It has even been shown to prevent and correct arrhythmias in those who were not magnesium-deficient (Am J Cardiol, 1989; 63: 43G-6G). Supplements of coenzyme Q10 (Tohoku J Exp Med, 1983; 141 [Suppl]: 453-63) and L-carnitine in animal studies (Arch Int Pharmacodyn Ther, 1975; 217: 246-50) have also proved beneficial, although the latter may not necessarily show the same results in humans.
* Consider herbs. Many herbal remedies have been mooted to help arrhythmias, but few have any large-scale human research behind them. One of the most potentially useful is hawthorn berry (Crataegus oxyacantha). A three-part review suggests that it has a tonic effect on the heart muscle and may improve blood flow, heart rate and heart muscle contractability (Planta Med, 1981; 43: 105-20; Planta Med, 1981; 43: 209-39; Planta Med, 1981; 43: 313-22). Doses ranged from 120-480 mg three times daily. Berberine and Gingko biloba are be helpful but, for arrhythmias, should only be used under the supervision of a qualified herbalist.