Protective Nutrients in Peanuts
Cracking open a peanut shell reveals an edible package of naturally protective nutrients. The fat, protein, and fiber in peanuts are all healthy and plant-based. Research on peanuts shows all of these components promote health and reduce the risk of chronic disease.
Peanuts and peanut butter are filled with many hard-to-get nutrients that play various roles in metabolism and health. People who eat peanuts tend to consume more key nutrients critical to health. In more than 15,000 people who consumed peanuts and peanut products, one study found that levels of vitamin A, vitamin E, folate, magnesium, zinc, iron, calcium, and dietary fiber were higher than those who did not consume peanuts (Griel, 2004). In a study that provided peanuts to participants for three weeks, blood magnesium levels increased to recommended levels in peanut eaters.
The story does not end here, because peanuts also provide unique bioactive components that act as antioxidants and have been shown to prevent disease. Arginine, an amino acid with high levels in peanuts, is a precursor to nitric oxide, which helps expand blood vessels and decrease blood pressure. Resveratrol, also found in grapes and wine, improves longevity and performance and reduces inflammation.
Peanuts also contain significant levels of phytosterols. Phytosterols are well known for their ability to reduce cholesterol levels and new research shows they have cancer-preventing qualities. Flavonoids are a class of compounds also found in peanuts that reduce inflammation and inhibit platelets from sticking to arteries.
Although you may not expect a handful of this tasty treat to provide so much nutrition, you can’t go wrong with the power-packed natural goodness of peanuts.
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Protein, Fats, & Fiber
Protein, fats, and fiber are the major components that make up peanuts. And these three factors are high quality when it comes to peanuts. Peanut protein is plant-based; peanut fat is unsaturated, and peanut fiber is the main type of complex carbohydrate in peanuts. Since peanuts have been shown to help prevent chronic disease and promote weight management, it makes sense that these three components are the building block of this delicious snack.
Peanuts have been recognized as a protein source since peanut butter became highly valued during World War II, when meat was not readily available. A one-ounce serving of peanuts—about a handful—is considered an excellent source of protein by the Food and Drug Administration, providing 7 grams of protein to your diet. Peanuts are actually classified as a legume and contain more protein than any other nut, with levels comparable to or better than one serving of beans.
Since the protein in peanuts is plant-based, it carries with it additional components promoting positive health benefits like fiber and unique bioactives, unlike animal protein. Peanuts are high in arginine, an amino acid, which is one of the building blocks of protein. This amino acid is a precursor to nitric oxide, a compound that expands your blood vessels. It has been thought to help decrease blood pressure.
In fact, one study, called the Optimal Macronutrient Intake Trial for Heart Health (OMNIHeart) (Appel, 2005), compared three diets to determine effects on blood pressure as well as the optimal diet pattern for reducing the risk of cardiovascular disease (Swain, 2008). The first diet was based on the Dietary Approaches to Stop Hypertension (DASH) diet, which emphasized carbohydrates. The second diet had a higher fat level from healthy unsaturated fats. The third diet had higher protein levels, more than half of which were from plant sources, including peanuts and peanut butter.
The OMNIHeart study showed that, in addition to the benefits of substituting healthy fat for carbohydrates in the DASH diet, substituting healthy protein also further reduced blood pressure and the risk of heart disease.
Adding peanuts to your diet is a great way to add healthy protein. Plus, you’ll be consuming key nutrients and bioactives like arginine that can improve your blood pressure, decrease chronic disease risk, and promote longevity.
Healthy Fats: Monounsaturated and Polyunsaturated Fat
Peanuts, peanut butter, and peanut oil are full of healthy fats—at least half of the fat in peanuts is heart-healthy monounsaturated fat, the kind found in olive oil and avocados. And more than 30% is polyunsaturated fat, another good fat key to a healthy diet.
For the first time, a “Key Recommendation” in the annual Dietary Guidelines recommends eating more plant-based proteins such as peanuts, because they contain healthy monounsaturated and polyunsaturated fats and other important nutrients. How exciting to know peanuts are a healthy food that taste great, too!
At Penn State University, a human study was conducted that providing people diets including peanuts and peanut butter or peanut oil as sources of high monounsaturated fat. The study compared this diet to 1) a low-fat diet higher in carbohydrates, 2) a diet high in olive oil, also high in monounsaturated fat, or 3) a traditional American diet high in saturated fat. Compared to the American diet, subjects following the high monounsaturated fat peanut diets lowered their total cholesterol levels by 11% and “bad” LDL cholesterol levels by 14%, while their “good” HDL cholesterol levels were maintained (Kris-Etherton, 1999). The benefits of the peanut diets on cholesterol levels were comparable to the olive oil diet. In addition, the peanut diets reduced triglyceride levels, which were increased in the low-fat diet.
Emerging data clearly shows that the amount and type of fat we eat can impact health in various ways (Kris-Etherton, 2002; Harris, 2009). Choosing peanuts, peanut butter, and peanut oil will help you to consume more healthy fats—the type best for heart health.
Bad Fats: Saturated and Trans Fat
Simply stated, because peanuts are high in healthy fats, that means that they are low in so-called bad fats—the ones that may not be as favorable to our health. “bad” fats include saturated fat and trans fat; saturated fat is found most often in animal products, whereas trans fat comes from the processing of partially hydrogenated oils.
Peanuts, peanut butter, and peanut oil are all low in saturated fat. Peanuts and their oil naturally do not have any trans fat and although a small amount of partially hydrogenated fat is used as a stabilizer to make peanut butter creamier, a U.S. Department of Agriculture study tested 11 commercial brands of peanut butter and found that in all brands, levels of trans fat were not detectable (Sanders, 2001). In fact, the amount of trans fat in peanut butter with 2% stabilizer is 156 times less than what is needed to reach the 0 gram trans fat cut-off on food labels (Sanders, 2001). Major health organizations such as the American Heart Association and the Institute of Medicine also recommend keeping intake of saturated and trans fats as low as possible.
Scientific studies show that when healthy fats replace bad fats in our diets, the risk of cardiovascular disease can be reduced (Hu, 1997). But that’s not all—this swap can also reduce the risk of developing chronic diseases as well as lower inflammation. Peanuts, peanut butter, and peanut oil are natural options that can help you keep with the guidelines and add more healthy fats to your diet. And since peanuts are a plant food, they are cholesterol-free!
When you think of fiber, you may think of fruits, vegetables, and whole grains. But you may not know that one serving of peanuts is also a good source of fiber, according to the Food and Drug Administration. Fiber is a healthy carbohydrate; eating it provides various benefits to our health. Fiber is commonly known for its ability to regulate the digestive system. It adds bulk to our diets, helping us to feel full, and it can slow the absorption of certain foods so that blood sugar is better controlled. Studies have shown that diets high in fiber can also contribute to lower levels of total and “bad” LDL cholesterol—plus, high-fiber diets are associated with a reduced risk of heart disease.
Over a third of the carbohydrate in peanuts is fiber. This may contribute to the fact that peanuts have a low glycemic index (GI) and glycemic load (GL) (Foster-Powell, 2002). On a 100-point scale, the GI of peanuts is 14 and the GL of peanuts is 1. This means that when we eat peanuts, our blood sugar and insulin levels stay balanced. In contrast, when we eat certain refined grains or sugary beverages, our blood sugar and insulin levels rise and fall quickly; this “spike” can lead to pre-diabetes and diabetes.
According to the 2010 Dietary Guidelines, fiber is one of the main nutrients lacking in the typical American diet. Consuming more plant-based protein sources, such as peanuts and peanut butter, can help you stay fuller longer. But America’s peanut comfort food can bring more than just feelings of contentment; fiber, in addition to the many other nutrients in peanuts, improves our health with each handful.
Vitamins & Minerals
Peanuts and peanut butter stand out as unique healthful foods for more than just their healthy fat, protein, and fiber. They have also been recognized as a great way to get multiple nutrients in a small portion from a single food source versus a supplement. Peanuts and peanut butter are chock-full of vitamins and minerals that are integral to growth, development, metabolism function, and immunity. All of the nutrients in peanuts work by multiple mechanisms and are likely having synergistic effects toward improving health status.
NIACIN helps convert food to energy. The digestive system, skin, and nerves also use niacin to function. Further, research shows that dietary niacin may protect against Alzheimer’s disease and cognitive decline (Morris, 2004). An ounce of peanuts is an excellent source of niacin providing a quarter of our daily needs.
FOLATE is especially important in infancy and pregnancy. This nutrient helps produce and maintain cells. Plus, research shows that people who consume higher dietary folate may have an advantage when it comes to prevention of heart disease (Rimm, 1998). An ounce of peanuts is a good source of folate, providing more than 10% of our daily needs.
PANTOTHENIC ACID is critical in the metabolism and synthesis of carbohydrates, proteins, and fats. An ounce of peanuts provides almost 10% of our daily needs.
THIAMIN (B1) is essential for the functioning of the heart, muscles, and nervous system. It also helps cells in the body convert carbohydrates into energy. An ounce of peanuts is a good source of thiamin, providing 10% of our daily needs.
RIBOFLAVIN (B2) has a key role in metabolizing fats, carbohydrates, and proteins. Just two servings provide 5% of our daily needs.
CHOLINE is critical for normal membrane structure and function. It is also important for lung function and memory development in infants. An ounce of peanuts provides almost 5% of our daily needs.
VITAMIN B6 is involved in protein and red blood cell metabolism and plays a role in the nervous and immune systems. A higher intake of dietary vitamin B6 may be beneficial for heart disease. An ounce of peanuts provides more than 5% of our daily needs.
VITAMIN E is commonly known as an antioxidant. It is also involved in immune function and regulating certain metabolic processes. Since studies that have supplemented vitamin E have been mixed, eating peanuts is a great way to get it from a dietary source. Vitamin E is considered a hard-to-get nutrient, as it was shown that more than 90% of men and women were not meeting the recommendations for intake (Gao, 2006). New research shows that there is more vitamin E in peanuts than was previously realized (Shin, 2009). An ounce of peanuts provides 20% of our daily needs of vitamin E and is considered an excellent source. That means that two servings provide almost half our daily needs.
MAGNESIUM plays multiple roles in the body. It maintains normal muscle and nerve function, thereby keeping our heart rhythm steady. Plus, it supports a healthy immune system, promotes normal blood pressure, keeps bones strong, and helps to regular blood sugar levels. Magnesium can also reduce the risk of stroke (Larsson, 2012). A number of studies of peanuts in diabetes have shown that magnesium intake is associated with reduced inflammation (King, 2005; Song, 2005) as well as a decreased risk of metabolic syndrome (Song, 2005) and type 2 diabetes (Kao, 1999; Lopez-Ridaura, 2004; Huerta, 2005; Larson, 2007). People who eat peanuts have been shown not only to increase their intake of magnesium, but also their blood magnesium levels. Peanuts are a good source of magnesium and just two servings provide a quarter of our daily needs.
PHOPHORUS primarily functions in the formation of bones and teeth. It also helps synthesize protein for the growth, maintenance, and repair of cells and tissues. A serving of peanuts is a good source of phosphorus, providing about 15% of our daily needs.
POTASSIUM is critical to maintaining fluid and electrolyte balance in the body. It is crucial for brain and nerve function and is necessary for normal growth and muscle development. One serving of peanuts’ potassium content accounts for almost 5% of our daily needs.
ZINC supports our immune systems, helps heal wounds, and is involved in building proteins. Zinc also supports normal growth and development during pregnancy, childhood, and adolescence. A serving of peanuts provides almost 10% of our daily needs.
IRON is an integral part of many proteins and enzymes that maintain good health. It is involved in oxygen transport and helps regulate cell growth and differentiation. A serving of peanuts provides almost 10% of our daily needs.
COPPER plays a role in the production of key proteins in the body, such as collagen and hemoglobin, which transports oxygen. A serving of peanuts is an excellent source of copper, providing more than 20% of our daily needs.
MANGANESE is a cofactor for many enzymes. A serving of peanuts is an excellent source of manganese, providing more than a quarter of our daily needs.
SELENIUM is an antioxidant that helps prevent cellular damage from free radicals. It regulates thyroid function and plays a role in the immune system. A serving of peanuts provides about 5% of our daily needs.
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Nutrients of Concern
It doesn’t take many peanuts to help bump up the levels of nutrients that we need each day. Just a small handful can naturally provide many of the vitamins and minerals that are hard to get. In fact, the Women, Infants and Children (WIC) program chose to include peanut butter in food packages because it contributes significant levels of iron, folate, vitamin E, and fiber.
According to the 2010 U.S. Dietary Guidelines, Americans tend to lack nutrients like potassium, dietary fiber, calcium, and vitamin D. One study looked at the diets of more than 15,000 American children and adults to assess the impact of peanuts. Researchers found that those who consumed peanuts and peanut products achieved higher Recommended Daily Allowances (RDAs) for vitamin A, vitamin E, folate, magnesium, zinc, iron, calcium, and dietary fiber than those who did not eat peanuts (Griel, 2004). Overall, peanut-eaters had higher-quality diets than non-eaters.
One more benefit: according to survey data, more than two-thirds of the peanut butter enjoyed in the U.S. is consumed with milk, providing a calcium boost to the participants’ diets. This means peanut butter can act as a magnet for other healthy foods contributing to an improved overall diet.
Another study examined data from the 2001-2004 “What We Eat in America,” National Health and Nutrition Examination Survey (NHANES). Children and adults who ate peanuts and peanut butter were also found to consume more critical nutrients. Levels of vitamin E, niacin, food folate, magnesium, copper, and potassium were significantly higher than in those who did not eat peanuts.
In a human study conducted at Purdue University, eating about 3 ounces of peanuts a day lead to significant increases in the intake of fiber, magnesium, folate, vitamin E, copper, and the amino acid arginine (Alpher, 2003). Also in the study, initial baseline values of blood magnesium fell below recommended levels, but these levels increased in all of the peanut eaters to above recommended levels corresponding with a range required to lower cardiovascular disease (CVD) risk.
Peanut Contribution to the Diet Versus Other Nuts
Compared to other nuts, peanuts contribute significantly more nutrients to the diet each day. At the 2007 Nuts & Health Symposium, researchers presented data on the average intake of vitamins and minerals for all nut users calculated from the 2001-2004 “What We Eat in America” National Health and Nutrition Examination Survey (NHANES). The breakout by average intake of each specific type of nut is shown here, based on a 2000-calorie intake.
Peanut, Peanut Butter, and Nut Nutrient Contribution to RDA in Men per 2000 Calories
Source: WWEIA, NHANES 2001-2004, 1 day, 19+ years
Peanut, Peanut Butter, and Nut Nutrient Contribution to RDA in Women per 2000 Calories
Source: WWEIA, NHANES 2001-2004, 1 day, 19+ years
Research has identified numerous compounds in peanuts and in their skin that may boast added health benefits beyond basic nutrition. Peanuts have been touted as a functional food with numerous functional components. These bioactive components have been recognized for containing disease preventative properties; some are antioxidants, while others are thought to promote longevity. Packaged together with vitamins, minerals, healthy fats, protein, and fiber, peanuts are a complex plant food that promote health with each bite. Simply put, peanuts are bioactive food in a shell.
If you want to get your blood moving, add more arginine to your diet. Peanuts can certainly help boost your levels as they have more arginine than any other whole foods. Arginine is an amino acid that is a precursor to nitric oxide. Nitric oxide helps to keep your arteries relaxed, improving blood flow. It is also known to improve healing time in your body’s tissues.
In attempts to stay youthful, many consume wine and grapes, as well as peanuts, because they all contain a compound thought to increase endurance and contribute to longevity. This compound is resveratrol. Resveratrol is known as a bioactive that reduces cardiovascular disease and cancer risk. It has antioxidant properties and also lowers levels of inflammation. All parts of the peanut contain resveratrol, from the roots to the skin—and even the shell (Chen, 2002; Francisco, 2008).
Many plants naturally produce resveratrol when they are under attack by pathogens such as bacteria. These attacks are a form of stress to the plant and studies are now showing that by stressing peanuts in various ways, the resveratrol content can be increased (Rudolf, 2005).
Southern-style boiled peanuts have the highest levels of resveratrol—even more than red wine and red grape juice on a part per million basis (Sanders, 2000). Peanut butter is not too far behind grape juice, with about three times more resveratrol than roasted peanuts with skins (Sobolev, 1999; Ibern-Gomez, 2000).
You may have noticed that there are certain brands of margarine that blend in phytosterols (or plant sterols) to their recipe. This is because these compounds have been found to lower your cholesterol. A handful of peanuts can naturally offer phytosterols leading to this same benefit.
Peanuts, peanut butter, peanut flour, and peanut oil are all filled with phytosterols that block the absorption of cholesterol from your diet. And emerging evidence shows that they also decrease inflammation and reduce the growth of various cancers (Woyengo, 2009). Researchers at the State University of New York at Buffalo found that phytosterols reduce prostate tumor growth by over 40% and decreased the chances of cancer spreading to other parts of the body by almost 50% (Awad, 2000).
The main phytosterols in peanuts include beta-sitosterol, campesterol, and stigmasterol, but new research has found that there are even more phytosterols in peanuts than previously thought. Plus, together with healthy fats, protein, and fiber found in peanuts, phytosterols may also be contributing to a decreased risk of heart disease (Awad, 2001).
Phenolic acids have antioxidant function and play a protective role against oxidative damage diseases like coronary heart disease, stroke, and various cancers. Roasted peanuts have levels comparable to other common foods like green tea and red wine, but when the skins are kept on, levels surpass those in berries (Francisco, 2009).
New research clearly shows that peanuts and their skins are exceptional sources of functional compounds, including phenolic acids (Francisco, 2008; 2009). If you look closely at your spoonful of peanut butter, you will notice small speckles. These speckles are ground peanut skins. Spreading peanut butter on your morning toast not only satisfies your taste buds, but also brings unique health benefits.
Flavonoids exist in all parts of the peanut plant. They act as a natural pesticide; some provide potent odors or bitter flavors as a defense system, while others are antimicrobial. In foods, flavonoids are responsible for color, taste, and protection of vitamins, enzymes, and fat oxidation.
A high intake of flavonoids is thought to protect against heart disease and cancer in various ways. They may also play a role in circulation soon after we eat. There is no official recommendation for flavonoids, but research is emerging as to how these bioactive compounds benefit our health. Peanuts and peanut butter are considered major food sources of flavonoids and contain the same types as those found in green and black tea, apples, red wine, and soybeans (Francisco, 2008).
The numerous bioactive components in peanuts contribute to their antioxidant capacity. Compared to well-known foods like green tea and red wine, peanuts have higher antioxidant capacity (Halvorsen, 2006). When peanuts are consumed with their skins, their antioxidant capacity doubles. And roasting can at times actually increase this capacity as well (Craft, 2010). Roasted peanuts with skins, for example, have higher antioxidant capacity than blueberries (Francisco, 2008). When you eat a handful of cocktail peanuts, you can be assured that your body is taking in a myriad of unique compounds to help prevent disease.