Walnuts

(And their “Sidekicks:” Almonds, Pistachios, Sesame Seeds, Peanuts, Pumpkin Seeds, Sunflower Seeds, Chia Seeds, Macadamia Nuts, Pecans, Hazelnuts, Pine Nuts, and Cashews)

A source of:

  • walnuts01Plant-derived omega-3 fatty acids
  • Vitamin E
  • Magnesium
  • Polyphenols
  • Protein
  • Fiber
  • Potassium
  • Plant sterols
  • Vitamin B6
  • Arginine
  • Resveratrol
  • Melatonin
Copyrighted Material*

Unless you’re allergic to tree nuts, you should definitely be adding walnuts to your diet. They’re great for your brain. Walnuts have the highest plant-based concentration of omega-3 essential fatty acids, which are necessary for proper brain function and to maintain the integrity of brain-cell membranes. Walnuts also have a perfect balance of omega-3 and omega-6 fats, which has been shown to decrease the incidence of cardiovascular disease.

walnuts02Walnuts contain a particular form of vitamin E (gamma-tocopherol) that has been shown to protect cardiovascular health. And a recent study done at the Marshall University School of Medicine in Huntington, West Virginia, reported in the journal Nutrition and Cancer, found that a modest amount of walnuts given to mice in addition to their daily diet reduced their rate of breast cancer by half.

Nuts in general have beneficial health properties. In fact, nuts, poultry, and whole grains have been shown to be three of the best foods for reducing the rates of cancer and cardiovascular disease. A six-year follow-up study of 11,895 participants found an inverse proportion of average yearly weight gain between those who did not consume nuts and those who consumed four or more servings per week. The authors of the study stated that even when the total energy (caloric) intake was slightly increased because of the addition of nuts to the diet, no significant weight gain was observed.

Several biological mechanisms may explain the lack of weight gain observed in association with nut consumption. Nuts are known to induce satiation (a feeling of fullness leading to a reduction in the total amount of food eaten in a single meal) and satiety (a feeling of fullness leading to a reduction in the frequency of meals). A 2008 study showed that 55 to 75 percent of the energy (caloric) intake from eating nuts may be compensated for by lower energy intake in future meals.

The satiation and satiety properties of nuts are attributed to the fact that they are rich in fiber and protein and also that they require significant chewing. The macronutrient content of nuts (fats, carbs, and protein) also increases the release of two gastrointestinal hormones that are associated with satiety. In addition, preliminary data suggest that the consumption of nuts might be correlated with a slight increase in the energy expended while one is at rest, or thermogenesis (the creation of heat during the burning of calories).

The incomplete mastication (too little chewing) of nuts, which is common, leads to a loss of energy-providing macronutrients—a bad idea when you’re starving, but great when you’re in a calorie-rich environment (as most Americans are). Finally, the monounsaturated  and polyunsaturated fat in nuts is more readily utilized for energy than saturated fat or trans fatty acids, thus leading to reduced fat accumulation.

A number of studies have reported that frequent nut consumption is correlated with lower rates of fatal and nonfatal coronary heart disease, has a consistent cholesterol-lowering effect, and protects men from hypertension. Peanut butter has also been shown to protect women from diabetes. Pecans, walnuts, and pistachios have  a high concentration of gamma-tocopherol, a form of vitamin E that is known to reduce inflammation. They have the highest concentration of total polyphenols and antioxidants, and the primary form of fat they contain is monounsaturated. All nuts are a good source of plant protein.

walnuts03Pistachios are the only carotenoid-containing nuts and one of the few non-leafy green sources of lutein, which is extremely important for eye health. Pistachios have more potassium and more phytosterols (which play a role in reducing cholesterol) than any other nut and have been shown to promote heart healthy blood lipid profiles. Studies have shown that pistachios reduce post-meal spikes in blood sugar and contribute to optimum functioning of the cells lining the blood vessels.

Almonds have shown a consistent ability to lower both LDL and total cholesterol and are rich in polyphenols (particularly in the skin), alpha-tocopherol (a type of vitamin E), the amino acid arginine, and the minerals magnesium, calcium, copper, manganese, and potassium.

walnuts04Cashews have more magnesium than any other type of nut, and increasing magnesium intake by 100 milligrams per day has been shown to reduce the rate of diabetes by 14 percent. They are also the least calorie-dense of any tree nut.

Ideally, nuts and seeds should be used to replace other foods with high-energy density or unhealthy snacks. One of my favorite brown-bag lunches is a mixture of dry-roasted soy nuts (lightly salted) dry-roasted sunflower seeds, raw pumpkin seeds, dry-roasted peanuts, dates, and prunes along with with a five-ounce can of Welch’s 100% grape juice. It’s delicious, filling, and gives me lots of energy for an afternoon of hard work.

*This brief summary contains copyrighted material from SuperFoods HealthStyle by Steven G. Pratt, M.D. and Kathy Matthews. Copyright © 2006 by Steven G. Pratt, M.D. and Kathy Matthews Inc., published by HarperCollins; and from SuperFoods Rx For Pregnancy by Steven Pratt, M.D. Copyright © 2013 by SuperFoods Partners, LLC, published by Wiley. All rights reserved.