Go Nuts! All nuts and seeds provide antioxidants, fiber, and healthy types of fat that help regulate blood sugar and lower cholesterol levels. A daily handful of almonds or hazelnuts, and certain seeds, helps provide Vitamin E – an essential brain cell protector. Recommended portions size is 1.5-3 oz/day as calories are relatively high (150-200 calories/oz for most nuts). Clinical research suggests however that people adding nuts to their usual diet do NOT gain weight, possibly because nuts are so filling people naturally cut back on other foods, and perhaps nuts also assist metabolism. Since we are all different, observe results for yourself. To limit sodium intake choose unsalted versions if possible; nuts themselves usually contain very little sodium.
Nuts and seeds are stars among brain healthy foods, and eating a daily portion of a variety will help you reduce LDL cholesterol, blood sugar, oxidative stress and inflammation, all risk factors for Alzheimer’s disease and some other brain diseases. Nuts and seeds are whole foods rich in plant proteins, unsaturated fatty acids, dietary fiber, minerals, vitamins and other antioxidants and phytosterols, consumed by humans throughout human history, but neglected in more recent decades. Nuts and seeds are increasingly recommended to help people prevent or treat heart disease, diabetes and other chronic diseases that are themselves risk factors for Alzheimer’s and other brain diseases.
Only almonds (Chauhan 2005 http://www.sfn.org/index.aspx?pagename=news_111405) and walnuts (Chauhan 2010 http://www.alz.org/icad/2010_release_large_071110_1200pm.asp) have been looked at specifically for impact on Alzheimer’s-related pathology, using AD transgenic mice. Both studies (by the same researcher, Abha Chauhan at New York State Institute for Basic Research in Developmental Disabilities) found significant positive effects on both lowering the problem A-beta protein and improving cognition in AD transgenic mice. Yet almond’s prominent feature is vitamin E and high mono-unsaturated fatty acid content and walnut’s is their high Omega-3 content. The most recent study found that a dietary addition of the equivalent for humans of just 1 to 1.5 oz of walnuts in the mice (who were previously impaired) diet improved learning, memory, emotional regulation and motor coordination.
Perhaps Alzheimer’s researchers will next look at pistachios featured recently by Tufts Nutrition Letter: “Penn State researchers report that pistachios not only lower “bad” cholesterol but also pack a potent antioxidant punch. Pistachios contain higher amounts of antioxidants, including beta-carotene, gamma-tocopherol and lutien than most other nuts, which may help pistachios combat inflammation in the body. “ Gamma-tocopherol has been reported by AD researchers (Martha Morris and others) to be especially important for the brain. A 1-oz serving of pistachios, with 160 calories, also offers an excellent source of vitamin B6, copper and magnesium; and are a good source of fiber, thiamin and phosphorus. (http://www.foodreference.com/html/a-pistachio-hea-208.html)
Nuts and seeds are an excellent source of plant protein and fiber. Fiber provides a feeling of satiety and helps decrease harmful LDL cholesterol by binding it in the intestinal tract and reducing its absorption. Plant sterols are another prominent group of compounds found in nuts and seeds. Plant sterols are believed to lower serum cholesterol levels thereby reducing the risk of coronary heart disease.
Nuts and seeds are also a great source of healthy mono- and poly-unsaturated fats. Monounsaturated fats help raise the “good” HDL cholesterol without contributing to a rise in the “bad” LDL cholesterol levels. Researchers have observed a decrease in cardiovascular disease in persons who include mono- and poly-unsaturated fatty acids in their diets. In addition, dietary intake of unsaturated fats has been shown to lower blood pressure, prevent blood clot formation, protect against irregular heart rhythm, and reduce inflammation.
A recent meta-analysis of 25 previous studies confirms this finding (see Joan Sabate, MD, Dr.PH lead author’s article in Journal of Nutrition, June, 2010. abstract at jn.nutrition.org/cgl/content/abstract/140/6/1093?etoc ) Most of the reviewed studies focused on almonds and walnuts; the average amount consumed by people in the intervention groups was 2.4 oz. The length of the studies ranged from 3 to 8 weeks. Tufts Health and Nutrition Letter report states, “Compared to control groups, participants adding nuts to their diets saw an average 5.1% decrease in total cholesterol, 7.4% decrease in “bad” LDL cholesterol, and 8.3% improvement in ratio of LDL to “good” HDL. Those with high triglyceride levels saw a 10.2% decline. Different types of nuts had similar effects.”
We agree with Dr. Sabate’s statement in Achives of Internal Medicine that “Dietary interventions to lower blood cholesterol concentrations and to modify blood lipoprotein levels are the cornerstone of prevention and treatment plans for coronary heart disease,” and suggest they are also the cornerstone of prevention and treatment plans for many brain diseases.
Polyunsaturated fatty acids include vegetable type Omega-3s (ALA) and Omega-6 fatty acids. Omega 3’s and 6’s are essential fatty acids which cannot be produced in the body so we must eat them as part of our diet. The body uses essential fatty acids to make eicosanoids, a group of compounds that participate in the immune response to injury and infection.
Nuts and seeds are also high in antioxidants, most notably Vitamin E. Almonds and hazelnuts are known to be especially high in vitamin E, and brazil nuts, peanuts and pine nuts are “good” sources (August newsletter) Antioxidants play a key role in reducing oxidative stress caused by the environment as well as chemical reactions in the body as part of metabolism. Eating more antioxidants may reduce cancer risks by protecting cell DNA from damage.
Other beneficial components found in nuts and seeds include the B-vitamins (including folate, niacin and thiamine) and minerals such as copper, magnesium, manganese, phosphorus, potassium, and sulfur (see Nutty Table #2 on our website). The B vitamins are critical to maintaining healthy brain function, both for mood and cognition. B vitamins are also important as coenzymes in metabolism and for helping to lower blood homocysteine levels. Research shows an association between elevated blood homocysteine and a higher risk of coronary heart disease, so keeping homocysteine levels low is recommended.
Monounsaturated fatty acids are found in many nuts and seeds with highest amounts in macadamia nuts, almonds, cashews, pecans, hazelnuts, pistachios, and peanuts. Sesame seeds also contain a high amount of monounsaturated fats. Nuts highest in Monounsaturated Fatty Acids (MUFA) include Macadamia (79% of total fat is MUFA), Almonds (65%!), Pecans (62%), Cashews (59%), Peanuts (50%), whereas Walnuts it is only 23% . Walnuts are prized for their high Omega-3 and Omega 6 content.
Omega-3 polyunsaturated fatty acids are found in higher quantities only in walnuts and some pine nuts, and also in flax seed and flax seed and canola oils. The Omega-6 fatty acids are particularly high in walnuts, with some found in most nuts, and high quantities also are found in pumpkin (pepita) seeds and sunflower seeds.
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