Every day, it seems, the press bombards us with bad news about food. A story a few days ago revealed that 24 percent of all raw chicken parts in the US go to market with salmonella contamination. Also this week, granny smith and gala apples were recalled due to listeria. Then there are the constant reports about the dangers of sugar, salt, dairy, processed foods, red meats, wheat, GMOs, and so forth. If you sometimes wonder if there's anything healthy left to eat, here's a story that might give you hope.
According to a study just completed at the David Geffen School of Medicine at The University of California, Los Angeles, walnuts may improve memory no matter your age or gender. 1 The research involved subjects aged 20 through 90 who were part of the larger National Health and Nutrition Examination Survey (NHANES). One group of participants ate a handful of walnuts daily; another participant group consumed no walnuts. Then the researchers performed a series of cognitive tests, controlling for everything except walnut consumption. The tests assessed reaction time, ability to recall stories, and the ability to learn and manipulate numbers.2
The results showed that the nutty group performed significantly better on all six of the exams, including taking considerably less time to respond to questions and to complete tasks. A particularly encouraging result revealed that seniors reaped special benefits from walnuts. On story recall exams, those over the age of 60 who had consumed walnuts scored a full 7.1 percentile points higher than those who didn't eat nuts. On digital substitution assessments, they scored 7.3 percentile points higher. Such results have led scientists to postulate that walnuts might be useful in preventing Alzheimer's.
This isn't the first time walnuts have performed like valedictorians in demonstrating their positive effect on brain function. A study published a few years ago in the British Journal of Nutrition found that those college students who ate half a cup of walnuts daily improved their performance by 11.2 percent on inferential reasoning assessments.3 Other studies have found that walnuts prevent cognitive decay and promote healthy brain functioning.
If the possibility that they'll enhance your brain power doesn't entice you to eat a handful of walnuts, you might consider that they have a host of other beneficial effects, too. Walnuts have been shown to promote heart health, to reduce breast and prostate cancer risk, and to reduce systemic inflammation.4 A recent study even found that walnuts may improve sperm quality.5 Plus, in spite of their reputation as fatty foods that pack on weight, research shows that nuts actually are good for the "bottom line," weight-wise. A recent study found that dieters who ate pistachios (okay, so they aren't walnuts, but like walnuts, they're from the tree-nut family) lowered their BMI more than a control group who snacked on pretzels.
What makes walnuts so health-enhancing? They're packed with antioxidants, vitamins and minerals, for one thing. However, 90 percent of the beneficial phytonutrients are in the walnut skin, meaning that if you stick to the prepared nuts you get in the store you're probably missing out on the nutritional punch. The skin does taste a bit bitter, but you're better off getting whole walnuts and eating the skin anyway. How many should you eat? The experts say about an ounce is ideal, which amounts to approximately 14 walnut halves a day.
Some of the phytonutrients in walnuts are rare and particularly health-enhancing, such as the quinone juglone--virtually unique to walnuts, as well as the phytonutrient tellimagrandin and a type of flavonoid called morin. Also, walnuts are the only nut that contains lots of alpha-linolenic acid (ALA), a health-enhancing omega-3 fatty acid--as long as your diet isn't omega-6 heavy, which prevents your body from metabolizing ALA. And finally, the form of vitamin E in walnuts, gamma-tocopherol, also is somewhat unique and particularly beneficial to heart health.
What about other nuts? Most also offer considerable health benefits. 6 Almonds, for instance, have more fiber than other nuts, and offer considerable cardiovascular benefits. In one study, participants who ate 20 percent of their calories from almonds over a four-month period lowered their "bad" LDL cholesterol and reduced insulin resistance more than a control group of non-almond eaters. Almonds also may enhance the immune system and increase good bacteria in the gut. The recommended serving size is a whopping 23 nuts at a time, which account for 170 calories and 15 grams of fat. Can you say "almond butter?"
Brazil nuts are a particularly rich source of selenium, valuable in fighting certain cancers, although more than five of these nuts daily may be counterproductive, as too much selenium isn't good for you. (Note: selenium is now being added to almost every vitamin pill.) Macadamias have the highest levels of monounsaturated fat of all nuts. Studies have shown that macadamia eaters reduced their triglyceride levels, total cholesterol, and LDL cholesterol by nearly 10 percent after adding the nuts to their diets. Ten macadamias a day will add 200 calories to your diet. Hazelnuts, pecans, and cashews also have remarkable health-enhancing properties, and pistachios have been shown to reduce lung-cancer risk. Like their cousin walnuts, pistachios are a type of "tree nut," rich in the antioxidant gamma-tocopherol. The good thing about pistachios is that you can eat a lot of them at a time: 50 only amount to 150 calories. Again, since you'll get plenty of fat from nuts and significant calories, too, you need to pay attention to the rest of your diet to make sure you're not overdoing it.
Given the significant benefits walnuts and other nuts confer, it seems a no-brainer to add them to your daily diet if you like the taste and you don't suffer from a nut allergy. The surprising fact is, though, that research indicates only 5.5 percent of those in the US regularly eat nuts of any variety--and most of those are in the unhealthy form of heavily salted nut mixes. Many of us apparently fear that we'll get fat from eating nuts, given their high fat content, and so we stick to cookies and pretzels for snacks, instead. The fact is that eating nuts tends to reduce BMI rather than increase it, something that certainly can't be said for carbohydrate-rich foods.
- 1. "A few walnuts a day may help improve memory." 22 January 2015. CBS News. 22 January 2015. http://www.cbsnews.com/news/walnuts-may-help-improve-memory/
- 2. Arab, L. and Ang, A. "A Cross Sectional Study of the Association Between Walnut Consumption and Cognitive Function Among Adult US Populations Represented in NHANES." 16 December 2014. California Walnuts. 22 January 2015. http://www.walnuts.org/health-and-walnuts/health-research/a-cross-sectional-study-of-the-association-between-walnut-consumption-and-cognitive-function-among-adult-us-populations-represented-in-nhanes/
- 3. Kelly, Diana. "The Brain-Boosting Nut." Prevention. 23 January 2015. http://www.prevention.com/health/health-concerns/nuts-and-health-how-walnuts-can-improve-your-memory
- 4. "Walnuts." 19-25 January. The World's Healthiest Foods." 22 January 2015. http://www.whfoods.com/genpage.php?tname=foodspice&dbid=99
- 5. Castillo, Michelle. "Eating walnuts daily may improve sperm quality." 16 August 2012. CBS News. 22 January 2015. http://www.cbsnews.com/news/eating-walnuts-daily-may-improve-sperm-quality/
- 6. Bender, Rachel Grumman. "Why You Should Go Nuts for Nuts." 11 November 2013. Everyday Health. 25 January 2015. http://www.everydayhealth.com/diet-and-nutrition/0406/why-you-should-go-nuts-for-nuts.aspx#01