March 2009 Issue

Inside the Shell: A Look at the Healthy Attributes of Nuts
By Valerie Yeager
Today’s Dietitian
Vol. 11 No. 3 P. 48

Studies and nutrient profiles suggest that cracking open a nut is worth the effort—the kernel awaiting within has both healthy and satiating qualities.

“I can’t eat nuts. Nuts will make me fat, and I’m trying to lose my lady hips,” replied my boss when I suggested he eat some almonds as an afternoon snack. His rather one-dimensional view of nuts is one that is perhaps all too common among consumers. Images of creamy peanut butter, peanut brittle, and those bowls of excessively salted nuts poised on the tables at a favorite watering hole often pop into people’s minds—including my own—when nuts are discussed. And those images can paint some pretty unhealthy pictures.

Sure, nuts contain fat, but since the majority of that fat is monounsaturated, one small handful per day may actually result in health gains. Recent studies have shown that diets that include a 1- to 1.5-ounce portion of nuts per day are more satisfying, leading people to eat less and control their weight.

Almonds, peanuts, walnuts, pistachios, pecans … and the list goes on. Each tasty type has its own health benefits, but all are packed with fiber, protein, antioxidants, and a variety of vitamins and minerals (see Table 1 for a full breakdown). Nuts may help reduce blood pressure, keep the heart healthy, and decrease the effects of metabolic syndrome. Compact, portable, and easily added to a variety of dishes, nuts are convenient in addition to being filling and nutritious—a rare and welcome combination.

Heed the Snacking Rules for Weight Control
According to Maureen Ternus, MS, RD, executive director of the International Tree Nut Council Nutrition Research & Education Foundation, regular nut consumers do not weigh more than those who do not consume nuts. “Tree nuts contain beneficial unsaturated fats (monounsaturated and polyunsaturated fats), protein, and fiber, all of which provide a feeling of fullness,” she adds.

Studies have indicated that nut consumers’ body mass indexes are lower than those who do not consume nuts, perhaps because the high energy density of nuts (50% to 75% of total calories)—which often worries people into thinking consumption will lead to instant weight gain—can have a counterintuitive effect on weight by suppressing appetite.1-3 This satiating effect is believed to be due to the macronutrient composition of nuts, which contain high levels of fat (primarily unsaturated and monounsaturated), fiber, and protein. In addition, nuts’ high unsaturated fat content may stimulate fat metabolism, thus enhancing energy utilization.4

But dietitians should stress one key factor to their clients and patients: moderation (see “How Many Nuts Constitutes 1 Ounce?” sidebar). Though Americans eat an estimated 2.5 million pounds of nuts on Super Bowl Sunday, according to the Calorie Control Council and the Snack Food Association, consumers should resist gluttonous urges on a regular basis. Sarah Ellis, MS, RD, past chair of the American Dietetic Association’s Vegetarian Nutrition Dietetic Practice Group, says that while the fat in nuts is healthful, nuts are also high in calories, and rationing nuts to 1 or 2 ounces per day is the most healthful way for people to reap the benefits without sacrificing their waistline. RDs should also advise clients to avoid the overly salted and honey-glazed versions, which are often packed with unnecessary sugar and sodium.

The Mediterranean Diet Gets Nutty
A late 2008 study published in the Archives of Internal Medicine shows that the Mediterranean diet, with the addition of nuts, may help manage metabolic syndrome. The study indicates that adding nuts was useful for managing metabolic abnormalities in older adults at high risk for heart disease.

Research has associated the Mediterranean diet—characterized by a high intake of cereals, vegetables, fruits, and olive oil; a moderate intake of fish and alcohol; and a low intake of dairy, meats, and sweets—with a lower risk for metabolic abnormalities. But the 2008 study, conducted by a university in Spain, randomly split its 1,224 participants into three groups to determine how the inclusion of nuts would impact metabolic syndrome in the participants, aged 55 to 80.

The researchers educated one group about consuming a low-fat diet and schooled the other two groups on the principles of the Mediterranean diet. They provided one of the Mediterranean diet groups with 1 liter of extra-virgin olive oil per week and the other with 30 grams of mixed nuts (one half walnuts, one quarter almonds, one quarter hazelnuts) per day.

At the beginning of the study, 61.4% of participants were considered to have metabolic syndrome. After one year, the prevalence of metabolic syndrome decreased by 13.7% in the nut group, 6.7% in the olive oil group, and 2% in the control group. Despite these differences, participants’ weight did not change over the one-year period. However, according to the study results, the number of individuals with large waist circumference, high triglycerides, or high blood pressure significantly decreased in the Mediterranean diet plus nuts group compared with the control group.

The study authors suggested that components of the diet, primarily the nuts, may have beneficial effects on pathophysiological characteristics of metabolic syndrome, such as oxygen-related cell damage, resistance to the effects of insulin, and chronic inflammation. They also reported that the Mediterranean diet’s high level of unsaturated fatty acids combined with the assorted nuts’ fiber, arginine, potassium, calcium, and magnesium is a powerful combo.

Breaking Down the Benefits
The potential benefits of nuts don’t stop there. As mentioned previously, each type of nut may have its own specific health benefits. While consumers can eat assorted nuts and reap the benefits of each, it may be helpful for those picky-eating clients and patients to be able to choose exactly which nuts have the health effects they’re looking for in addition to the taste they crave.

Five Nutritional Nutcases

Almonds
A 1-ounce serving of almonds contains more fiber than any other nut and is an excellent source of vitamin E, magnesium, and manganese and a good source of fiber, copper, riboflavin, and phosphorus. One ounce also contains 6 grams of protein and 12 grams of heart-healthy unsaturated fats.5 Along with hazelnuts, almonds contain the most vitamin E of any nut. Vitamin E, which acts as a natural antioxidant, can help prevent coronary heart disease, boost the immune system, reduce the risk of cataracts, and play a role in healthy skin and hair.

Peanuts
Channing Pollock, an American playwright and critic, once said, “No man in the world has more courage than the man who can stop after eating one peanut.” While this is clearly an overstatement, the man had a point. For lovers of this most common nut, controlling intake can prove difficult, especially when it comes to the beloved peanut butter.

While natural peanut butter may take precedence over the processed kind many Americans grow up eating, clinical dietitian Julia Edwards, RD, of the University of Pittsburgh Medical Center Braddock, points out that a single serving of a favorite processed brand can still be a nutritious addition to a client’s diet—particularly if spreading peanut butter on apples or celery helps picky eaters consume more fruits and vegetables. Edwards adds that she eats a peanut butter sandwich almost every day because the protein in the peanuts promotes satiety.

Peanuts and healthful peanut products are satisfying and are also an economical and convenient addition to any diet. Marjorie Geiser, RD, NSCA-CPT, owner of MEG Fitness in California, recommends that her clients focus on consuming healthful “plant fats” and suggests 1 ounce of nuts (and one piece of fruit, if needed) as the perfect afternoon snack. A vending machine staple, peanuts are always a far better option than a bag of chips. “People are eating fats anyway, so they may as well replace a regular fatty snack with nuts,” adds Geiser. At least those nuts are natural and packed with nutrients, and they’ll sustain that full feeling for longer as well.

Peanuts are a well-rounded nut, with 6.7 grams of protein, 6.1 grams of carbohydrate, 2.3 grams of fiber, vitamin E, folate, niacin, magnesium, and potassium.6

Pecans
The only major tree nut that grows naturally in North America, the pecan shouldn’t be overlooked as something to enjoy only at the holidays. Pecans are naturally free of sodium and contain more than 19 vitamins and minerals, including vitamin A, vitamin E, folic acid, calcium, magnesium, phosphorus, potassium, several B vitamins, and zinc. One ounce of pecans provides 10% of the recommended daily value of fiber, and they contain large quantities of the cancer-fighting elegiac acid. Also rich in protein, 1 ounce of pecans is roughly equivalent to two servings from the meat and bean group and 2 tablespoons of oil. Research released by the USDA in March 2008 shows that pecans contain more antioxidants than any other nut, even overshadowing walnuts, and are among the top category of foods (ranking in the top 20) with the highest antioxidant capacity.

Pistachios
Offering the most nuts per 1-ounce serving, pistachios provide more than 30 vitamins, minerals, and phytonutrients. An excellent source of potassium, vitamin B6, copper, and manganese, pistachios are also rich in protein, fiber, thiamin, and phosphorus.7 Ellis points out that pistachios also contain arginine, which metabolizes to nitric oxide, helping open blood vessels and reduce blood pressure.

Walnuts
In his 2004 best-selling book SuperFoods Rx, Steven Pratt, MD, identified walnuts as one of his 14 “SuperFoods,” ranked among other nutrition notables such as beans, broccoli, soy, and spinach. While lower in fiber and monounsaturated fats than many other nuts (including almonds, pistachios, and pecans), walnuts are significantly higher in omega-3s than other tree nuts and peanuts, and they also have a high level of antioxidants. Eating more antioxidant-rich foods such as walnuts may help combat oxidative stress in the body and reduce the risk of cancer and other diseases.

Any Downsides?
Unfortunately, like most good things, there’s a downside to nuts—in this case, allergies. The prevalence of nut allergies is rising—the incidence doubled between 1997 and 2002, according to random phone surveys for research published in the Journal of Allergy and Clinical Immunology—and it’s rare to see a restaurant menu or food package without the general disclaimer that the product may have come in contact with nuts. For the 3 million people with nut allergies, peanuts and tree nuts can be deadly. If you have a patient or client with a nut allergy, 100% avoidance of foods containing nuts or that may have been in contact with nuts is vital.

Pregnant women may also do well to avoid nuts. According to a study conducted in the Netherlands in summer 2008, expectant mothers who ate nuts or nut products (eg, peanut butter) daily during pregnancy increased their children’s risk of developing asthma by more than 50% over women who rarely or never consumed nut products during pregnancy.8

However, feeding nuts to young children may help them avoid peanut allergies later in life. A recent study in the Journal of Allergy and Clinical Immunology shows that children who avoided peanuts in infancy or early childhood were 10 times as likely to develop peanut allergies than those who were exposed to peanuts.

Mix It Up
Just like some of your patients and clients who can’t seem to stomach fruits and vegetables, there are plenty of people who aren’t big fans of eating a handful of plain or raw nuts. Nevertheless, there are countless ways to incorporate them into a meal plan. Ground nuts can be stirred into pancake or waffle batter, sprinkled over yogurt or cereal, or used as a coating for chicken or fish before baking. Nuts can be tossed on top of salads and added to a favorite brownie or cookie recipe. Toasting nuts in a dry skillet is a great way to intensify their flavor without adding salt or sugary seasonings.

Even with these methods, remind your clients to watch their intake. Stay within that 1- to 1.5-ounce portion size per day, and nuts become not only a satisfying addition to the diet but also one packed with surprising health benefits. With nuts’ attributes in mind, when your clients go to a baseball game, the only thing they have to feel guilty about is throwing those shells on the ground.

— Valerie Yeager is an editor and freelance writer based in Philadelphia.

References
1. Alper CM, Mattes RD. Effects of chronic peanut consumption on energy balance and hedonics. Int J Obes Relat Metab Disord. 2002;26(8):1129-1137.

2. Rajaram S, Sabaté J. Nuts, body weight and insulin resistance. Br J Nutr. 2006;96(Suppl 2):S79-S86.

3. Sabaté J, Cordero-Macintyre Z, Siapco G, Torabian S, Haddad E. Does regular walnut consumption lead to weight gain? Br J Nutr. 2005;94(5):859-864.

4. Jump DB. N-3 polyunsaturated fatty acid regulation of hepatic gene transcription. Curr Opin Lipidol. 2008;19(3):242-247.

5. Duyff RL. 365 Days of Healthy Eating From the American Dietetic Association. Hoboken, N.J.: Wiley; 2003.

6. The Peanut Institute. Peanuts — Mother Nature’s whole food. 2004. Available at: http://www.peanut-institute.org/NutritionBasics.html

7. Pistachio Health. Available at: http://www.pistachiohealth.com

8. Willers SM, Wijga AH, Brunekreef B, et al. Maternal food consumption during pregnancy and the longitudinal development of childhood asthma. Am J Respir Crit Care Med. 2008;178(2):124-131.

How Many Nuts Constitutes 1 Ounce?
Almonds: 24
Brazil nuts: 6 to 8
Cashews: 18
Hazelnuts: 21
Macadamias: 10 to 12
Peanuts: 28
Pecans: 20 halves
Pistachios: 47
Walnuts: 14 halves

— Source: USDA National Nutrient Database for Standard Reference, Release 20, 2007

Table 1
Nutrient Comparison of Nuts

 

Almonds

Cashews

Peanuts

Pecans

Pistachios

Walnuts

Calories (kcal)

163

163

166

196

161

185

Protein (g)

6.02

4.34

6.71

2.6

6.05

4.32

Total fat (g)

14.01

13.14

14.05

20.4

13.03

18.49

Saturated fat (g)

1.058

2.596

1.954

1.752

1.575

1.737

Monounsaturated fat (g)

8.757

7.744

6.985

11.567

6.865

2.533

Polyunsaturated fat (g)

3.422

2.222

4.447

6.128

3.94

13.374

Cholesterol (mg)

0

0

0

0

0

0

Carbohydrate (g)

6.14

9.27

6.1

3.93

7.59

3.89

Fiber (g)

3.5

0.9

2.3

2.7

2.9

1.9

Calcium (mg)

75

13

15

20

31

28

Iron (mg)

1.05

1.7

0.64

0.72

1.19

0.82

Magnesium (mg)

76

74

50

34

34

45

Phosphorus (mg)

137

139

101

79

137

98

Potassium (mg)

200

160

187

116

295

125

Zinc (mg)

0.87

1.59

0.94

1.28

0.65

0.88

Copper (mg)

0.282

0.629

0.19

0.34

0.376

0.45

Manganese (mg)

0.648

0.234

0.591

1.276

0.361

0.968

Thiamin (mg)

0.06

0.057

0.124

0.187

0.238

0.097

Riboflavin (mg)

0.287

0.057

0.028

0.037

0.045

0.043

Niacin (mg)

0.96

0.397

3.804

0.331

0.404

0.319

Pantothenic acid (mg)

0.133

0.345

0.395

0.254

0.145

0.162

Vitamin B6 (mg)

0.041

0.073

0.073

0.06

0.361

0.152

Folate (mg)

14

20

41

6

14

28

Arginine (mg)

0.693

0.494

0.875

0.334

0.598

0.646

Vitamin K (mg)

0

9.8

0

1

3.7

0.8

Vitamin E (mg)

7.43

0.26

1.96

0.4

0.55

0.2

Total phytosterols (mg)

31

45

62

29

61

20

*Almonds, pecans, and walnuts are unroasted; cashews, peanuts, and pistachios are dry roasted.

— Source: USDA National Nutrient Database for Standard Reference, Release 20, 2007

 

 

 

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