A nut is defined as a dry, single-seeded fruit with a high oil content, which guarded by a tough shell/outer layer.1,2 Certain legumes (such as peanuts) are also regarded as nuts.1,2 There are different types of trees and bushes all over the world that produce nuts; however, some plants, such as the peanut plant, produce the nuts underground. Typically, nuts are harvested once a year, though timing of harvest varies according to geographical region and type of nut.2
According to historians, nuts have been harvested and prized for their nutritional content for thousands of years. Indeed, experts claim that Romans offered sugared almonds as gifts, and even the Old Testament mentions harvesting pistachios and almonds.1,2
Though tiny, nuts pack an incredible nutritional punch; in general, nuts are a good source of monounsaturated and polyunsaturated fats (the “good” fats), protein, vitamins, minerals, and fiber,; thus, they are considered a nutrient-dense food choice. Here, we take a crack at listing the many health benefits nuts can offer.
BRAIN AND IMMUNE HEALTH
Vitamin E. Nuts are loaded with vitamin E, which has antioxidant properties that protect cells from free radical damage that can negatively impact the brain and increase risk of Alzheimer’s disease, Parkinson’s disease, age-related dementia, and even depression.3 Daily consumption of nuts has been linked to managing and preventing neurodegenerative diseases and age-related brain dysfunction.3 Vitamin E is also a strong lipid-soluble antioxidant found in immune cells, and helps to regulate immune functioning and reduce risk of infection, disease, and inflammation. T cell and lymphocyte (white blood cell) production and overall cell functioning, including maintaining cell membrane integrity and cell division, are all regulated by vitamin E.5,6 Walnuts and almonds harbor the greatest ability to combat damage caused by free radicals and associated oxidative stress.4
Magnesium. Magnesium can be found in nuts as well. This mineral combats memory lapses that come with aging.7 Increasing magnesium intake has been shown to enhance the brain’s ability to memorize information and learn. Apparently, only 32 percent of the US population achieves the daily recommended amount of magnesium in their diet.7,8 Almonds, cashews, and peanuts are particularly good sources of magnesium.
Flavenoids. Many studies have shown that flavonoids play a role in protecting the brain, and nuts are great sources of lutelon and anthocyanidin, two types of flavenoids. Lutelon consumption has been linked to enhanced memory, and daily intake of nuts has been associated with a slower rate of cognitive aging.9 Anthocyanidin, another type of flavonoid, has anti-inflammatory and antioxidizing properties that repair tissue damage and control excessive oxidative stress, similar to the actions of vitamin E.9
Fiber. Nuts are also good sources of fiber, which helps keep inflammatory responses in the body at bay.10 Lower levels of tumor necrosis factor-alpha (TNF-alpha) and interleukin-6 (IL-6)—pro-inflammatory immunity cells (cytokines) that signal immune/inflammation responses—have been reported in people who maintain a high intake of fiber.10
Omega-3 fatty acid. Omega-3 fatty acid also helps to regulate the inflammatory process in the body, as well as reduce pain associated with inflammation, by lowering levels of TNF-alpha and IL-6.10,11 Walnuts are the best source of these fats, followed by almonds, macademia nuts, hazelnuts, pecans, and peanuts.
Selenium. Selenium is a mineral that also helps to regulate excessive immune responses in the body, which is common in individuals who suffer from chronic inflammation.12–14 Brazil nuts are the optimal source for this mineral.
Zinc. The mineral zinc is also an antioxidant tht helps decrease pro-inflammatory immunity cells and reduce risk for infection.3,15 Being a trace mineral, the body only needs small amounts of zinc.15 Cashews are considered an excellent source of zinc.
Phytochemicals. Phytochemicals are bioactive compounds that assist in combating illness. Plant sterols, a type of phytochemical, has been associated with reduced risk of cancer. Nuts are considered good sources of phytochemicals.16
CARDIOVASCULAR HEALTH
The standard American diet (termed the Western Diet) typically comprises foods high in saturated and trans fats, processed sugars, and sodium; most Americans exceed the daily recommended intake for each but do not meet the recommended daily intake of fiber, fruits, vegetables, and healthy fats.17–19 Poor dietary choices can raise cholesterol levels and blood pressure and cause weight gain, obesity, Type 2 diabetes, and chronic inflammation, all of which are risk factors for cardiovascular disease.17-19 Briefly put, certain medical conditions and lifestyle choices are correlated to the development and exacerbation of heart disease, the number one cause of death in the United States.20 There are many components of nuts that can help combat these risk factors and enhance cardiovascular health.
The monounsaturated and polyunsaturated fats in nuts can improve HDL (“good”) cholesterol levels and artery function and decrease LDL (“bad”) cholesterol levels, reducing the risk of heart attacks and disease.21 In particular, polyunsaturated fat fuels the function sof vitamin E.22
Nuts are loaded with tocotrienols, a form of vitamin E, whichcan delay the buildup of plaque in the arteries.23 Additionally, alpha-linolenic acid (ALA) fatty acids, one of the three omega-3 fatty acids, decrease the inflammation and oxidation associated with cardiovascular diseases; these fats can also lower blood pressure.17-19 Findings from relative studies indicate that people who regularly consume whole pecans have a 26 to 33 percent decrease in oxidized, “bad” cholesterol levels nearly 2 to 8 hours subsequent to consumption.24 In particular, pistachios have been shown to decrease triglycerides—the dietary fats found in the bloodstream—in individuals with obesity and/or diabetes. The plant sterols found in nuts has also be shown to moderate cholesterol levels.24 Staff at the Mayo Clinic and the American Heart Association recommend eating four servings of unsalted nuts a week to reap these heart-health benefits.25
DIGESTIVE HEALTH
An increased intake of fiber is correlated to a lowered reoccurrence of colon polyps and an overall reduced incidence of colon cancer.10,26,27 Fiber stimulates butyrogenic activity in the gut microbiome, which has antineoplastic effects, reduces inflammation, and protects the colon. Insoluble fiber helps clean out the digestive track and maintains regularity.10,26,27 This is particularly beneficial to those individuals who suffer from constipation; irregular bowl movements allow prolonged contact between carcinogens in the stools and the gut wall. Nuts with the highest fiber content include (in accordance with one ounce) almonds: 3.5g; pistachios: 2.9g; hazelnuts: 2.9g; pecans: 2.9g; peanuts: 2.6g; macadamias: 2.4g; and Brazil nuts: 2.1g.25-27
Cashews, almonds, pistachios, chestnuts, and hazelnuts also contain prebiotics, which sustain and fuel the growth of the beneficial bacteria in the body’s gastrointestinal tract, assisting in churning out nutrients for cells in the colon and maintaining the health and functions of the microbiome.28
SKIN HEALTH
The epidermis contains natural fats, known as lipids, that maintain strength of the skin’s protective barrier.29,30 There are three prevalent fats—cholesterol, ceramides, and fatty acids—all of which play a role in the elasticity, barrier response, and appearance of skin. These fats are produced by the body, but supplements and dietary intervention can ensure the skin is provided with the necessary amount. Fatty acids, in particular, are responsible for the balance of lipids, and an abundance is associated with youthful, healthy skin. Consuming omega-3s and omega-6s—polyunsaturated fatty acids—can help keep the skin’s protective barrier intact, as well as reduce the inflammatory and aging response of the dermis.29,30 Favorable sources of omega-3s and omega-6s include walnuts and peanuts/ peanut butter.
Vitamin E is essential to skin’s antioxidant defenses against ultraviolet radiation.29 Its antioxidant properties help protect against free radicals that can damage and age the skin. Vitamin E is especially abundent in almonds, peanuts, and hazelnuts.
Like vitamin E, selenium has antioxidant properties, especially against irradiation-induced oxidative stress.12,29 It performs this protective function by activating selenium-dependent antioxidant enzymes located in the plasma membrane of epidermal keratinocytes (cells that form the structural protein, keratin.) The best dietary source of selenium is Brazilian nuts, which contain nine times the recommended daily amount an adult requires.5,9,29
Zinc is on the forefront of skin’s defense system.14,29 The zinc found in cashews protects the cells that make collagen when exposed to ultraviolet rays (UV). When the skin becomes injured (e.g., a cut), zinc boosts the enzyme and protein production of surrounding tissues to combat infection, manage inflammation, and create and transport new cells to the injured area.29 The immune function of zinc also helps to control acne-induced irritation and inflammation.14
OVERALL HEALTH AND WELL-BEING
Protein conserves energy and organ function, prevents muscle atrophy, and promotes tissue growth.31 Moreover, protein is essential for building muscle mass and overall sustaining life.31,32 Nuts are mainly recognized for their high protein content, and depending on the type, snacking on handfuls of nuts can assist in meeting the daily recommended 50g of protein most adults need.31–33 Peanuts, almonds, pistachios, cashews, walnuts, and hazelnuts are excellent sources of protein. Regarding mental health, look to the mighty cashew. Zinc, which comprises 11 percent of a cashew, has been associated with reduced anxiety and anxiety-related symptoms.34 Overall, a few servings of nuts a week can help keep us alive longer.33
PREPARATION AND CONSUMPTION
Nuts can be enjoyed by the handful as a snack; used to top salads, yogurt, cereal, and oatmeal; blended and made into a sauce or nut butter; or mixed with dried fruits, seeds, and other ingredients to create a hearty trail mix. The possibilities of adding nuts into your daily routine are truly endless. However, raw, unsalted nuts offer the greatest nutritional value. Glycotoxins produced by roasting nuts can actually promote cognitive and nerve health decline and increase the risk of Alzheimer’s disease by hindering sirtuin activity (which is responsible for preventing the accumulation of plaque in the brain).35
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