By Kathleen Doheny
WebMD Health News
Reviewed by Brunilda Nazario, MD
Sept. 10, 2014 -- Once viewed by some as a food too high in calories to enjoy on a regular basis, nuts are getting new respect.
Two recent studies have touted the benefits of nuts for blood sugar control. One, published in Diabetes Care, found that eating pistachio nuts daily may help people at risk of getting diabetes control their blood sugar. A second, published in PLOS One, found that tree nuts -- including almonds, Brazil nuts, cashews, and pecans, among others -- may improve blood sugar control in people with type 2 diabetes.
These are only a couple of many recent studies that point to the health benefits of eating nuts in moderation.
WebMD asked two dietitians to dish on what else we need to know about these crunchy treats.
What are some of the top health benefits of nuts, as found in recent research?
Aside from helping with blood sugar, nuts have been linked with improving heart health and helping with weight control. A study from last year even suggested that eating nuts of any type may help you live longer.
Doctors have known about the heart-health benefits for a while, says Christine Rosenbloom, PhD, RDN. She's a professor emerita of nutrition at Georgia State University and a nutrition consultant. The value of nuts to lower cholesterol has also been acknowledged, says Jessica Crandall, RDN. She's the director for outpatient nutritional counseling at Sodexo Denver Wellness and Nutrition.
What's more, researchers from Purdue University found that nuts are not linked with weight gain, despite their relatively high calorie count. An ounce of nuts has 160-200 calories, depending on the type.
What are the "good things" in nuts, and how do these substances work in our bodies?
The protein in nuts can help keep blood sugar stable, Crandall says. The fiber helps with weight control, partly by helping us feel full. Some say the ''crunch'' value also adds to a feeling of fullness.
Nuts are about 80% fat, but mostly ''good'' unsaturated fats. Other good stuff in nuts includes magnesium (which helps maintain the calcium-potassium balance in your body), folate (critical for a healthy brain), and vitamin E (to maintain a healthy circulatory system). They also have arginine, an amino acid that's needed to make nitric oxide, which relaxes the blood vessels.
Plus, nuts can improve insulin sensitivity, which lowers diabetes risk, research has shown.
Are some nuts better or healthier than others?
"I think they are all healthy," Rosenbloom says. "All are similar in protein, fiber, and fat [content]."
Still, she says, some nuts are higher in certain nutrients than others. For instance, almonds are the best source of vitamin E, she says. Cashews are a good source of magnesium, and pistachios are rich in the phytonutrients important to eye health, she says. "Eating a variety of the different kinds will give you all those [benefits]."
While peanuts are considered a legume by the peanut industry, since they're grown in the ground, nutritionists consider them as healthy as other nuts because of their similar nutritional properties, Crandall says.
Nuts can be high in calories. Should you avoid them if you're trying to lose weight?
Decades ago, Rosenbloom used to tell her clients trying to lose weight to avoid nuts. She doesn't these days, though. Many people are surprised when she tells them to have nuts in moderation.
"What the research shows is, when you are consuming nuts -- 1 or 2 ounces a day -- your total calorie count does not go up," Crandall says. It makes sense, she says, because nuts might often take the place of other snacks, like potato chips, that are less filling. Nuts' protein and fiber, on the other hand, helps you feel full.
Pay attention to how many you eat, though, Rosenbloom says.
What is a serving of nuts?
In the studies, researchers often use 1 to 2 ounces as a serving, Rosenbloom says. She generally recommends an ounce as a serving size, with maybe 2 ounces for a very active man.
How many nuts do you get for an ounce? It depends on the nut, Crandall says. You can have roughly 25 almonds for an ounce-worth, but only 17 macadamia nuts.
An ounce of pistachios is about 49 nuts.
"I usually recommend recommend people get unsalted," Rosenbloom says. If those unsalted nuts are too bland, Crandall tells her patients to sprinkle on cinnamon and broil them, or add rosemary and garlic.
Rosenbloom warns clients to keep nuts in their proper place in the diet. "If you are taking a half-cup of walnuts and putting it over a hot fudge sundae, that's not the healthy way to eat nuts."
Rather, she says, add nuts to a tossed salad or a stir-fry dish.
People who like to buy the large, economy-size bags of nuts should portion them out at home, using small bags or containers for a 1-ounce serving, Rosenbloom says.
Why are so many studies funded by the nut industry?
"One reason is there is so little government funding," she says. That's true for much medical research.
The nut industry, she says, ''has been smart. They know they have a health [related] product but need to be able to have research conducted to show that."
Typically, she says, the industry ''gives grants to the top researchers in the field." Those grants mean the researchers do their work independently, without influence from the funder or manufacturer. Also, the studies are peer-reviewed before they're published in a journal.
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