The word “nut” refers to any fruit which is a hard-shelled, edible kernel.  Nuts used for culinary purposes, however, also include “seeds” which are not botanically true nuts, and are described as “large, oily kernels found within a shell.”  I’ll discuss other seeds, like pumpkin seeds, sunflower seeds and sesame seeds in a future post.

History

Nuts, including the wild almond, prickly water lily, acorns, pistachio and water chestnuts were a major part of the human diet 780,000 years ago. There is evidence that prehistoric humans developed an assortment of tools to crack open nuts during the Pleistocene period.

Nutrition

Nuts have been linked to lower cholesterol, better heart health, weight control and lower cancer risk. They do contain a relatively large quantity of calories, however. But they offer unsaturated and monounsaturated fats, vitamins, and essential amino acids. Many nuts are good sources of vitamin E, vitamin B₂, folate, fiber, and the essential minerals magnesium, phosphorus, potassium, copper, and selenium.  They are most healthy in their raw unroasted form, as up to 15% of the fats are destroyed during the roasting process. Unroasted walnuts have twice as many antioxidants as other nuts or seeds. Nuts used for food, whether true nut or not, are among the most common food allergens.

Almonds – At traditional Italian weddings, five almonds signify five wishes for the bride and groom: health, wealth, happiness, fertility, and longevity. Almonds, which are edible seeds of drupe (or stone) fruits contain the most fiber and are richest in vitamin E. Twenty years of dietary data collected on over 80,000 women from the Nurses’ Health Study shows that women who eat least 1 ounce of nuts, peanuts or peanut butter each week have a 25% lower risk of developing gallstones. One ounce is only 28.6 nuts or about 2 tablespoons of nut butter. High almond consumption of almonds, however, can interfere with calcium absorption.

Brazil nuts – Did you know that in Brazil, it is illegal to cut down a Brazil nut tree? Botanically, it is actually a seed. The Journal of Medicinal Food suggests that brazil nuts combined with soy can inhibit prostate cancer by inhibiting the growth of cancer cells. Just one Brazil nut contains 100% of the recommended daily amount of the mineral selenium, which may also help prevent bone cancer and breast cancer. High levels of selenium can be harmful, however, so stick to one serving a day.

Cashews – A few years ago when my husband and I were hiking in a rain forest in Belize, we saw cashews growing. They are actually seeds of a fruit, the cashew apple, and hang from the bottom of the fruit! Cashews are particularly rich in iron and zinc. Iron helps deliver oxygen to all of your cells, which can prevent anemia, and zinc is critical to immune health and healthy vision. Cashews are also a good source of magnesium: One ounce provides almost 25 percent of your daily need. Magnesium may help improve memory and protect against age-related memory loss, according to a study in the journal Neuron.  In Panama, the cashew fruit is cooked with water and sugar for a prolonged time to make a sweet, brown, paste-like dessert

Chestnuts – Chestnuts depart from the norm culinary nuts in that they have very little protein or fat, their calories coming chiefly from carbohydrates. They are the only nut which contains vitamin C, however. In Modena, Italy, they are soaked in wine before roasting and serving, and are traditionally eaten on Saint Simon’s Day in Tuscany. They are not to be confused with horse chestnuts which are inedible because they contain a toxic substance. How do you tell the difference? Horse chestnut trees have “palmate” leaves (multiple leaves on one stem that fan out like a palm), whereas edible sweet chestnut trees have individual alternate leaves. However, edible chestnuts always have a tassel or point on the nut—something that your finger can feel as a point, and the horse chestnut has no point—it is smooth and roundish all over.

Hazelnuts – During World War II, an Italian chocolate-maker named Ferrero couldn’t get enough cocoa, so he mixed in some ground hazelnuts instead. Then he made a soft and creamy version and Nutella was born! Hazelnuts are noted for their high level of monounsaturated fats which can improve cardiovascular health and control type 2 diabetes. They are also rich in the antioxidant vitamin E which may prevent cataracts, macular degeneration, maintain healthy skin and reduce risk of dementia.

Macadamia nuts – The macadamia nut was discovered by British colonists in Australia in 1857.  William Herbert Purvis nurtured them and planted them as seedlings on the Big Island of Hawaii in 1882, where one of his original trees is still growing and producing fruit today. Macadamias are the white kernels of a follicle type fruit. A Pennsylvania State University study found that people who added macadamia nuts to their diets reduced their triglyceride, total cholesterol, and LDL cholesterol levels by 10%.

Pecans – The pecan is the only major nut tree that grows naturally in North America. The name “pecan” is a Native American word of Algonquin origin that was used to describe “all nuts requiring a stone to crack.” Early Native American tribes used to produce a fermented intoxicating drink from pecans called “Powcohicora” (where the word “hickory” comes from).  A Journal of Nutrition study found that consuming pecans can lower LDL cholesterol levels by as much as 33%. The vitamin E found in pecans may delay progression of degenerative neurological diseases like amyotrophic lateral sclerosis (ALS), also known as Lou Gehrig’s Disease.

Peanuts – Eating peanuts at particularly nerve-wracking points during NASA missions is a long standing tradition at their Jet Propulsion Laboratory that dates back to the Ranger program in 1964. Now they eat peanuts on launch days for good luck! Botanically, these “nuts” are small sized, underground fruit pods and are actually legumes. Peanuts contain high levels of a antioxidant that is thought to reduce the risk of stomach cancer and resveratrol, which helps protect against cancers, heart disease, degenerative nerve disease, Alzheimer’s disease, and viral/fungal infections.

Pine nuts – The effects of pine nuts as an aphrodisiac were well known by the Greeks and Romans. Pliny mentioned them in his book The Loving Arts and a second-century medical practitioner recommended them mixed with honey to relieve “sexual woes.” We are most familiar with pine nuts as one of the ingredients in pesto, along with garlic, basil, and olive oil. Pine nuts are seeds from several varieties of coniferous trees. Pine nuts contain the essential omega-6 fatty acid which triggers the release of hunger-suppressant enzymes and recent research has shown its potential use in weight loss by curbing appetite.  They are the richest source of manganese, which helps the body develop resistance against infectious agents and scavenge harmful oxygen-free radicals. Furthermore, pine nuts are one of gluten free tree nuts, and therefore, are a popular ingredient in the preparation of gluten-free diets.

Pistachios – Greece has a long-standing tradition of treating pistachios as exclusively royal food. The pistachio honey cake that is famous for its combination of the nut with honey, is said to have originated in the Greek island of Aegina. Greeks celebrate National Pistachio Day with a festival each year. Pistachios are the seeds from a drupe or stone fruit like the almond. The University of Texas M.D. Anderson Cancer Center researchers found that eating just two ounces of pistachios daily may reduce lung cancer risk because they contain an antioxidant that is a form of cancer-fighting vitamin E. They are rich in potassium, essential for healthy nervous system and muscles, and a good source of vitamin B6, which can improve your mood and fortify your immune system.

Walnuts – Walnuts have been linked to love and fertility throughout history and their reputation as an aphrodisiac dates back to ancient Greece and Rome. In addition to containing the most antioxidants of all nuts which help protect your body from the cellular damage that contributes to heart disease, cancer, and premature aging, walnuts are the richest in omega-3 fatty acids which fight inflammation.

Resources

http://www.everydayhealth.com

http://www.health.com

http://www.mayoclinic.org

http://www.nutrition-and-you.com

http://www.worldshealthiestfoods.com