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March 2011

Lifestyle and atrial fibrillation
Hypertension often “white coat”
TIA associated with higher heart risk
Potassium may lower heart/stroke risk
Low vitamin D precedes Parkinson’s
Fish lowers macular degeneration

Lifestyle and atrial fibrillation

The left atrium is a heart chamber that contributes about 20 to 30 percent of the blood to the ventricle to pump out through the aorta. Atrial fibrillation (AF) is a condition in which the atrium quivers instead of beating regularly. This diminishes blood flow to the body and usually diminishes exercise capacity. While the condition is often intermittent (paroxysmal AF), if it is prolonged, the pooling of blood in the atrium can lead to blood clots sent to the brain (stroke) or to the abdomen. New information suggests that lifestyle choices play a role in the incidence of atrial fibrillation.

In a study of 14,598 subjects, researchers evaluated known risk factors for AF, including high blood pressure, elevated body mass index, diabetes, smoking, and a history of heart disease. The subjects were followed for 17 years, during which time 1520 cases of AF were identified. The modifiable risk factors were responsible for an estimated 56 percent of AF cases. The most significant of these contributing risk factors was hypertension.

Modifying lifestyles can reduce these risk factors and lower the risk of heart disease at the same time. Maintaining a normal weight, not smoking, and exercising to control blood pressure and blood sugar can help. This is hardly shocking, but the reduction of AF by 56 percent is a surprise. (Huxley RR, et al., Absolute and attributable risks of atrial fibrillation in relation to optimal and borderline risk factors: The Atherosclerosis Risk in Communities (ARIC) Study. Circulation. 2011 Mar 28. [Epub ahead of print]).

Paroxysmal AF may last for a few seconds or minutes, or even for several days. If the AF is persistent (usually for more than 5 days, depending on other risk factors) patients are often treated with an anticoagulant (Coumadin),  or sometimes just with aspirin to prevent strokes. Coumadin treatment has its own risks, specifically the danger of hemorrhage in the brain (bruising on the arms and legs is quite common).

Depending on the cause, AF tends to become more frequent with time, so it is important to try to prevent it through lifestyle changes. Some patients are greatly helped by supplements of magnesium and the amino acid taurine (5000 to 15,000 mg daily), and other supplements that help the heart (coenzyme Q10, L-carnitine).

Hypertension often “white coat”

Patients are often diagnosed with hypertension (blood pressures over 140/90) and treated with multiple drugs, when much of the time the blood pressure is only elevated when they are in the doctor’s office. This is the so-called “white-coat” syndrome. Anxiety can raise blood pressure, and sometimes people are anxious about having their blood pressure taken because they are worried about the result (sort of a self-fulfilling prophecy).

A recent study of 68,045 patients with hypertension found 8295 of them to have resistant hypertension, the kind that stays elevated while being treated with three or more different kinds of drugs (including a diuretic). The researchers then did 24-hour ambulatory blood pressure monitoring when the patients were no longer in the doctor’s office. This consisted of blood pressure testing every 20 minutes while patients were living and working normally.

Tested this way, 37.5 percent of the subjects had normal blood pressures during everyday activity but elevations in the doctor’s office, suggesting that white-coat syndrome is far more common than expected. (de la Sierra A, et al., Clinical features of 8295 patients with resistant hypertension classified on the basis of ambulatory blood pressure monitoring. Hypertension. 2011 Mar 28. [Epub ahead of print].)

This means that more than one third of resistant hypertension patients are being treated with drugs unnecessarily. These drugs include beta-blockers, diuretics, angiotensin-converting-enzyme (ACE) inhibitors, and angiotensin receptor blockers (ARBs). The expense and potential side effects become much more of a problem when you consider that the treatments are unnecessary in the first place.

The other 62.5 percent of the subjects had responded to drugs, and they tended to have more risk factors, such as smoking, diabetes, and a worse cardiac profile. However, even in this group, they might well have responded to lifestyle changes (diet, exercise, relaxation techniques, dietary supplements) and then not needed medications. (This could also be the case for the other 60,000 subjects with treatable hypertension, further reducing medication needs.)

TIA associated with higher heart risk

Transient ischemic attacks (TIA, also called “mini-strokes) are short episodes of low circulation to the brain causing temporary faintness, loss of balance, visual disturbances, and even short loss of consciousness. Although disturbing, they are not indicators of brain cell death, but they are signs of poor cerebral circulation and possible later stroke.

The compromise of circulation to the brain is only part of the picture, because atherosclerosis is rarely isolated to one region, and TIAs may indicate widespread hardening of the arteries. A new study shows that TIAs are indicators of future problems with heart disease. (Burns JD, et al., Incidence and predictors of myocardial infarction after transient ischemic attack: a population-based study. Stroke. 2011 Apr;42(4):935-40. Epub 2011 Mar 24.)

In this review of studies of both TIA and heart attacks (myocardial infarction, or MI), researchers found that the occurrence of MI was doubled among those with TIAs compared to the general population. Among patients who were under 60, TIAs, were associated with a 15-fold risk of later MI. The use of lipid-lowering drugs (statins) at the time of the TIA led to a 3-fold risk of later MI.

TIAs are an indicator of serious circulatory problems. It becomes all the more important to take care of cardiovascular risk factors through lifestyle and supplements because the drug therapies for heart risks appear to worsen the cardiac outcome for patients with TIAs.

Potassium may lower heart/stroke risk

Potassium is an essential nutrient mineral that helps regulate the heartbeat and is essential for nerve conduction and muscle contraction. A healthy diet should have 4500 to 6500 mg per day (potassium in the diet is harmless, so it is hard to develop any side effects from too much). It is found in a wide variety of fruits, vegetables, whole grains, and beans. Healthy whole foods have a ratio of about 9 to 1 of potassium over sodium, but processed foods have that ratio almost reversed, with far too much added sodium and not enough of the whole foods that contain potassium.

In a new report, researchers identified 11 studies with 247,510 male and female participants who were followed for 5 to 19 years. They evaluated the risk of heart disease and stroke relative to the intake of potassium. During the follow-up periods they found 7066 strokes, 3058 coronary heart disease events, and 2479 total vascular disease events. (D'Elia L, et al., Potassium intake, stroke, and cardiovascular disease a meta-analysis of prospective studies. J Am Coll Cardiol. 2011 Mar 8;57(10):1210-9.)

They found that for every increase of 1.64 grams of potassium (1640 mg), stroke risk declined by 21 percent, and there was a trend for lower cardiovascular events. This result is not clearly related to the potassium itself, as the foods that contain it are just those that are known to have other health benefits (more vitamins, minerals, flavonoids, antioxidants) and the potassium may just be a marker for healthier diets. Non-prescription supplements of potassium have too little to be effective in themselves.

Low vitamin D precedes Parkinson’s

Low vitamin D levels are associated with numerous conditions, such as loss of strength, autoimmune disorders, diabetes, and some cancers, among others. A new study using stored blood samples from patients who later developed early Parkinson’s disease suggests another problem from low vitamin D.

Among 157 subjects deemed appropriate for analysis, the average vitamin D level was 26.3 ng/ml at the start of the study and 31.3 at the end of the study when they already had Parkinson’s symptoms. In the data, 70 percent of those who developed Parkinson’s had low vitamin D in their earlier blood samples. This was apparently not due to their getting less vitamin D as the condition worsened, because their levels unexpectedly went up by the end of the study. (Evatt ML, et al., High prevalence of hypovitaminosis D status in patients with early Parkinson disease. Arch Neurol. 2011 Mar;68(3):314-319.)

Virtually all subjects had relatively low vitamin D levels, which should be from 50 to 100 ng/ml, although deficiency is defined as levels below 30 ng/ml.

Fish lowers macular degeneration

A new study shows that omega-3 fatty acids from fish (EPA and DHA) can lower the risk of developing age-related macular degeneration (AMD). In this study, 39,876 female health professionals were evaluated with food-frequency questionnaires. They were followed for an average of 10 years. (Christen WG, et al., Dietary {omega}-3 fatty acid and fish intake and incident age-related macular degeneration in women. Arch Ophthalmol. 2011 Mar 14. [Epub ahead of print].)

At the end of the study, they had found a total of 235 cases of AMD. Those with the highest intake of DHA had a 38 percent lower risk of AMD compared to those with the lowest intake. Those with the most EPA intake had a 34 percent lower risk.

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Information herein is not medical advice or direction. All material in this newsletter is provided for information only. Its contents should not be used to provide medical advice on individual problems. Consult a health care professional for medical or health advice.

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