Nutrition Archive

Research We’re Watching

In the 2015–2020 Dietary Guidelines for Americans, the emphasis shifted from healthy foods to healthy eating plans. Scientists are also focusing on the role of one's entire diet in preventing osteoporosis.

A team of German researchers analyzed data from more than 90,000 women enrolled in the Women's Health Initiative (WHI), who were ages 50 to 79 when they entered the study.

They follow their own advice to enjoy lots of vegetables, legumes, lean protein, and a fruit-based dessert.

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Following a healthy diet is a proven and powerful way to lower your risk of heart disease. But do you ever wonder if doc-tors actually practice what they preach, especially with regard to their eating habits? While we obviously can't speak for all of them, four Harvard physicians with diverse ethnic backgrounds agreed to share examples of their favorite heart-healthy dinner menus.

Dr. Enrique Caballero, assistant professor of medicine

A native of Mexico, Dr. Caballero directs the Latino Diabetes Initiative at the Joslin Diabetes Center; his research interests include cardiovascular disease prevention.

Watching the sugar in your diet can help you control your weight and potentially avoid serious chronic health problems — for example, heart disease and diabetes.

You might be surprised at how many of the "healthy" foods you eat contain sugar. Energy bars, fruit, flavored yogurt — all are "good" foods, but many of them have a lot of sugar. So, the first step to reducing excess sugar in your diet is to read labels carefully and opt for products that are lower in sugar.

The advice to eat chocolate should be taken with a grain of salt.

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Like bees swarming a melting candy bar, the media buzz around the purported health benefits of chocolate has been hard to ignore. The possibility that such a sumptuous treat might actually be good for your heart is very sweet news, indeed.

But there's a lot more to this story that we need to understand before going hog wild in the candy aisle, says Dr. Howard Sesso, associate professor in the division of preventive medicine at Harvard-affiliated Brigham and Women's Hospital. "Simply recommending that people eat dark chocolate as a way of improving health is very misleading, since chocolate products tend to have a significant amount of fat, sugar, and calories." Instead, he and colleague Dr. JoAnn Manson are embarking on the Cocoa Supplement and Multivitamin Outcomes Study (COSMOS), a four-year trial involving 18,000 participants that is designed to tease out the intricacies of chocolate's health-promoting nutrients (www.cosmostrial.org).

Various herbs and other supplements have been touted for their ability to improve cholesterol levels. Here's what the research shows — and doesn't show — about some of the best-known products.

Hawthorne. The leaves, berries, and flowers of this plant are used to make medicine that was traditionally used to treat cardiovascular diseases. It may lower cholesterol by increasing the excretion of bile and decreasing the body's production of cholesterol. Verdict: It may possibly help.

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Think about this the next time you fill your plate with kale or spinach: a study published in JAMA Ophthalmology Jan. 14, 2016, found that boosting leafy green vegetable intake is associated with a reduced risk of developing glaucoma, a leading cause of blindness.

Harvard researchers analyzed the dietary information reported by more than 100,000 men and women in two long-term studies, each lasting more than 25 years. Those who ate the most leafy greens had a risk of developing glaucoma that was 20% to 30% lower than that of those who ate the least. What's the link? Glaucoma causes damage to the optic nerve, through increased pressure from fluid in the eye or impaired blood flow to the optic nerve. Leafy greens are loaded with nitrate, which the body converts to nitric oxide. "Nitric oxide is important for maintaining optimal blood flow, and possibly for keeping eye pressure low," speculates Dr. Jae Hee Kang, the lead author of the study and a Harvard Medical School assistant professor. The study doesn't prove that leafy greens reduce glaucoma risk; it only shows an association between the two. Eating leafy greens is also linked to lower rates of inflammation, cancer, heart disease, and even macular degeneration.

When it comes to preventing cardiovascular disease, some experts feel the recommendations may not go far enough.

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Every five years, the U.S. government issues a new edition of the Dietary Guidelines for Americans, a report that "helps Americans make healthy choices for themselves and their families." But if you're concerned about having a heart attack or stroke, the advice in the latest update doesn't entirely agree with what many nutrition experts—as well as the American Heart Association—recommend.

We asked Dr. Walter Willett, professor of epidemiology and nutrition at the Harvard T.H. Chan School of Public Health, to share his thoughts about where the new guidelines may not be aggressive enough for people at risk for heart disease. Here's his advice on five dietary components of note.

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The popular eating pattern that's good for your heart—the Mediterranean diet—is also good for your waistline, according to a review of five studies that compared the Mediterranean diet with other weight-loss diets.

The trials, which included a total of 998 overweight or obese people, pitted the Mediterranean diet (which is rich in vegetables, fruits, grains, beans, and olive oil but light on meat, dairy, and eggs) against one or more of three other diets: a low-fat diet, a low-carb diet, and the American Diabetes Association (ADA) diet.

Drinking caffeinated coffee or tea may help you feel more awake and alert. But for healthy people, it probably won't cause palpitations—a noticeably strong, fast, or irregular heart beat. That's according to a new study of nearly 1,400 older adults in the Jan. 26, 2016, Journal of the American Heart Association.

Researchers relied on data from food questionnaires and Holter monitors, which recorded each participant's heart rhythm for a 24-hour period. About 60% of the people in the study said they consumed more than one caffeinated product (coffee, tea, or chocolate) a day. People who consumed more of those products were no more likely to have palpitations than those who imbibed less, the authors found.