Heart Health Archive

Research we're watching

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Noshing on a handful of nuts on most days of the week has been linked to a lower risk of obesity and heart disease. New research may help explain why: walnuts appear to activate a brain region involved in appetite and impulse control.

For the study, nine people with obesity drank a smoothie that contained about 14 ground walnut halves or a placebo smoothie (identical in taste and calories) for five consecutive days. After a month on their regular diets, the participants returned for another five days, during which the placebo group drank walnut smoothies and vice versa. On day five of both periods, they underwent brain imaging tests while looking at pictures of desirable foods (such as burgers and cake), less desirable foods (vegetables), or neutral pictures of rocks and trees.

Your body depends on the mineral potassium for many bodily functions, including keeping control of the electrical balance of your heart, metabolizing carbohydrates, and building muscle.

Low potassium levels can cause muscle weakness and heartbeat irregularities. On the other hand, too much potassium can cause your heart to stop.

It may help prevent a heart attack or stroke, but it comes with the risk of bleeding.

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Maybe you've heard about people who take a low-dose aspirin each day to ward off heart problems. Since aspirin is a medicine you've probably used now and then without a problem, and since it is available without a prescription, you might consider trying a daily low-dose aspirin yourself. Don't do it. Unlike deciding to take a multivitamin, taking a daily aspirin isn't something you should decide to do on your own.

Aspirin therapy is typically prescribed to people who have atherosclerosis of the arteries of the heart or brain, or risk factors for such disease. Just who should take a daily aspirin, how much aspirin, and what type of aspirin are hotly debated issues, with clinical trials under way in search of answers. "Until those results are in, you should talk to your doctor before starting aspirin," says Dr. Deepak Bhatt, a cardiologist and the editor in chief of the Harvard Heart Letter.

Even if you exercise regularly, sitting for long periods during the day is unhealthy for your heart.

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On average, we spend more than half of our waking hours sitting down: working at a computer, watching television, traveling in a car, or doing other sedentary things such as reading or chatting with friends. But long stretches of uninterrupted sitting have a range of undesirable effects that may harm your heart, says Dr. Beth Frates, who directs wellness programming for the Stroke Research and Recovery Institute at Harvard-affiliated Spaulding Rehabilitation Hospital.

"Sedentary behavior affects your body in many different ways, even down to the molecular level," she notes.

Ask the doctor

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Q. I heard my cardiologist say to another doctor that I have a "full metal jacket." What does that mean?

A. Cardiologists use the term "full metal jacket" to refer to a long series of stents in one of the heart's three major arteries. Stents are tiny metal cylinders, often with drug coatings, that help prop open arteries to restore blood flow to the heart. They're placed inside arteries during an angioplasty, in which a doctor snakes a thin, flexible tube (catheter) through the blood vessels to a narrowed section. A deflated balloon at the tip of the catheter then inflates, pushing fatty plaque against the artery wall and expanding the stent.

Ask the doctor

Q. My doctor added metoprolol to the diuretic medication I'm taking for my high blood pressure. Ever since then, I've felt more tired than usual, and my wife says I seem a little depressed. Could the new drug be to blame, and if so, is there anything I can do about it?

A. Metoprolol (Lopressor, Toprol) belongs to a class of drugs known as beta blockers. These drugs — which make the heart beat slower and with less force — used to be given as a first-choice treatment for high blood pressure. But they can cause fatigue and depression in some people, as well as other side effects, such as erectile dysfunction.

Because many factors are involved, make sure your doctors talk to each other if you need an invasive test or procedure.

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Millions of people with cardiovascular disease take drugs that help prevent blood clots, which can lodge in a vessel and choke off part of the blood supply to a leg, a lung, or the brain. These potentially lifesaving medications, known generally as anticoagulants, include warfarin (Coumadin) and a class of drugs called non–vitamin K antagonist oral anticoagulants, or NOACs (see "Anti-clotting drugs: The old and the new").

However, if you're taking one of these drugs and need an invasive procedure — anything from a tooth extraction to a hip replacement — managing the risks can be tricky, says cardiologist Dr. Gregory Piazza, assistant professor of medicine at Harvard Medical School. "There's a higher-than-normal risk of bleeding during and after the procedure, because your blood doesn't clot as easily," he says.

You may be storing unhealthy amounts of visceral fat even if your weight appears normal.

For decades, the body mass index (BMI) has been the gold standard for gauging obesity-related heart disease risk. But this handy tool doesn't always tell the whole story. It extrapolates your body fat percentage based on your height and weight (see www.health.harvard.edu/bmi-calculator). But the formula can't assess how or where your body stores its excess fat — a distinction that is crucial for cardiovascular health. By some estimates, the BMI misclassifies nearly 50% of people who are at higher disease risk from excess fat, meaning that you can be overfat even when you're not overweight.

The secret life of belly fat

Some people are genetically programmed to have a lot of fat tissue under the skin, which is deployed to store extra food energy during times of scarcity. But other people have very few of these designated fat cells, explains Dr. Christos Mantzoros, professor of medicine at Harvard-affiliated Beth Israel Deaconess Medical Center.

Factors that harm your heart may be bad for your brain.

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During middle age, factors that leave you prone to a heart attack or stroke — high blood pressure, diabetes, and smoking — may raise your risk of developing dementia a quarter-century later, new research suggests. All three things affect your vascular (blood vessel) health.

The recent study, which adds to the growing evidence linking heart health to brain health, has elements that make findings especially reliable, says Dr. Gad Marshall, a Harvard Medical School assistant professor of neurology. "For understanding the vascular risks for dementia, this study is as close to definitive as we can get," he says.