Peanuts are a type of nuts, originating in South America.
Scientifically known as Arachis hypogea, peanuts go by a variety of names, such as groundnuts, earth nuts, and goobers.
In the US, peanuts are rarely eaten raw. Instead, they are most often consumed as roasted and salted whole peanuts or peanut butter.
Other products made from peanuts include peanut oil, peanut flour, and peanut protein. Peanut products are used in a variety of foods; desserts, cakes, confectionery, snacks, and sauces.
Not only do peanuts taste good, they are also rich in protein, fat, and various healthy nutrients.
Studies show that peanuts may be useful for weight loss, and are linked to reduced risk of cardiovascular disease.
The table below contains detailed information on all the nutrients in whole peanuts.
Fat in Peanuts
Peanuts are high in fat.
In fact, they are classified as oilseeds. A large proportion of the world’s peanut harvest is used for making peanut oil (arachis oil).
The fat content ranges from 44-56% and is mainly mono- and polyunsaturated fat, most of which is made up of oleic acid (40-60%) and linoleic acid (, , , , ).
Bottom Line: Peanuts are high in fat, consisting mostly of mono- and polyunsaturated fatty acids. They are often used to make peanut oil.
Peanuts are a good source of protein.
The protein content ranges from 22-30% of calories (, , ), making peanuts a rich plant-based protein source.
The most abundant proteins in peanuts, arachin and conarachin, can be severely allergenic to some people, causing life-threatening reactions ().
Bottom Line: For a plant food, peanuts are an exceptionally good source of protein.
Peanuts are low in carbs.
In fact, the carb content is only about 13-16% of total weight (, ).
Being low in carbs and high in protein, fat, and fibers, peanuts have a very low glycemic index (), which is a measure of how quickly carbs enter the bloodstream after a meal.
This makes them particularly suitable for people with diabetes.
Bottom Line: Peanuts are low in carbs. This makes them a good dietary choice for people with diabetes.
Vitamins and Minerals
Peanuts are an excellent source of various vitamins and minerals.
The following vitamins and minerals are in particularly high amounts in peanuts ():
- Biotin: Peanuts are one of the richest dietary sources of biotin, which is particularly important during pregnancy (, ).
- Copper: A dietary trace mineral that is often low in the Western diet. Copper deficiency may have adverse effects on heart health ().
- Niacin: Also known as vitamin B3, niacin has various important functions in the body. Niacin has been linked with reduced risk of heart disease ().
- Folate: Also known as vitamin B9 or folic acid, folate has many essential functions and is especially important in pregnancy ().
- Manganese: A trace element found in drinking water and most foods.
- Vitamin E: A powerful antioxidant, often found in high amounts in fatty foods.
- Thiamin: One of the B-vitamins, also known as vitamin B1. It helps the body's cells convert carbs into energy, and is essential for the function of the heart, muscles, and nervous system.
- Phosphorus: Peanuts are a good source of phosphorus, a mineral that plays an essential role in the growth and maintenance of body tissues.
- Magnesium: An essential dietary mineral with various important functions. Magnesium intake is believed to protect against heart disease ().
Bottom Line: Peanuts are an excellent source of many vitamins and minerals. These include biotin, copper, niacin, folate, manganese, vitamin E, thiamin, phosphorus, and magnesium.
Other Plant Compounds
Peanuts contain various bioactive plant compounds and antioxidants.
In fact, peanuts are as rich in antioxidants as many fruits ().
Most of the antioxidants are located in the skin of peanuts (), which is rarely eaten and then only with raw peanuts.
Here we will focus on those plant compounds found in peanut kernels, which are eaten more often.
A few noteworthy plant compounds found in peanut kernels include:
- p-Coumaric acid: A polyphenol that is one of the main antioxidants in peanuts (, ).
- Resveratrol: A powerful antioxidant that may reduce the risk of cancer and cardiovascular disease (). Resveratrol is most notably found in red wine.
- Isoflavones: A class of antioxidant polyphenols, the most common of which is genistein. Categorized as phytoestrogens, isoflavones are associated with a variety of health effects, both good and bad ().
- Phytic Acid: Found in plant seeds (including nuts), phytic acid may impair the absorption of iron and zinc from peanuts and other foods eaten at the same time ().
- Phytosterols: Peanut oil contains considerable amounts of phytosterols, the most common of which is beta-sitosterol (). Phytosterols impair the absorption of cholesterol from the digestive tract ().
Bottom Line: Peanuts contain various plant compounds. These include antioxidants, such as coumaric acid and resveratrol, as well as antinutrients like phytic acid.
Obesity is on the increase in the US ().
Peanuts have been widely studied with regard to weight maintenance.
Despite being high in fat and calories, peanuts do not appear to contribute to weight gain.
In fact, observational studies have shown that peanut consumption may help maintain a healthy weight status and reduce the risk of obesity (, , , ).
These studies are all observational, which means that they cannot prove causation. In fact, it is well possible that the consumption of peanuts may be a marker of other healthful behaviors, which contribute to reduced weight gain.
However, one small study in healthy women showed that when peanuts were given as a substitute for other sources of fat in a low-fat diet, the women lost 3 kg over a 6-month period, despite being told to maintain their initial weight ().
Another study found that when 89 g (500 kcal) of peanuts were added to the daily diet of healthy adults for 8 weeks, they did not gain as much weight as expected ().
Various factors make peanuts a weight loss friendly food:
- Peanuts may reduce food intake by promoting satiety to a greater extent than other common snacks, such as rice cakes (, ).
- Because of how satiating peanuts are, people appear to compensate for increased peanut consumption by eating less of other foods ().
- When whole peanuts are not chewed well enough, a portion of them may pass through the digestive system without being absorbed (, ).
- The high content of protein and monounsaturated fat in peanuts may increase energy expenditure (, ).
- Peanuts are a source of insoluble dietary fiber, which is linked with reduced risk of weight gain (, ).
Bottom Line: Peanuts are very filling, and can be considered an effective component of a weight loss diet.
Other Health Benefits of Peanuts
In addition to being a weight loss friendly food, eating peanuts has been linked with several other health benefits.
Heart disease is one of the leading causes of death worldwide.
Observational studies indicate that consuming peanuts (and other types of nuts) may protect against heart disease (, , ).
Various mechanisms have been discussed as a potential explanation for these effects, which are likely the result of many different factors (, , ).
One thing is clear, peanuts contain a number of heart-healthy nutrients. These include magnesium, niacin, copper, oleic acid, and various antioxidants, such as resveratrol (, , , ).
Bottom Line: As a source of many heart-healthy nutrients, peanuts may help prevent heart disease.
Gallstones affect approximately 10-25% of adults in the US ().
Two observational studies suggest that frequent peanut consumption may cut the risk of gallstones in both men and women (, ).
Most gallstones are largely composed of cholesterol. Therefore, the cholesterol-lowering effect of peanuts has been suggested to be a possible explanation ().
Further studies are needed to confirm these findings.
Bottom Line: Peanut consumption may cut the risk of gallstones.
Adverse Effects and Individual Concerns
Aside from allergies, eating peanuts has not been linked with many adverse effects.
However, peanuts can sometimes become contaminated with aflatoxin, a toxic substance produced by molds.
Peanuts can sometimes be contaminated with a species of mold (Aspergillus flavus), which produces a toxic substance called aflatoxin.
The main symptoms of aflatoxin poisoning include loss of appetite and yellow discoloration of the eyes (jaundice), typical signs of liver problems.
Serious aflatoxin poisoning can lead to liver failure and liver cancer ().
The risk of aflatoxin contamination depends on how peanuts are stored, being more common under warm and humid conditions, especially in the tropics.
Aflatoxin contamination can be effectively prevented by proper drying of peanuts after harvest and keeping temperature and humidity low during storage ().
Bottom Line: If stored under warm and humid conditions, peanuts can become contaminated with aflatoxin, which may cause liver problems.
Peanuts contain a number of so-called antinutrients, substances that impair the absorption of nutrients and reduce nutritional value.
Of the antinutrients in peanuts, phytic acid is particularly noteworthy.
Phytic acid (phytate) is found in all edible seeds, nuts, grains and legumes. In peanuts, it ranges from 0.2-4.5% ().
Phytic acid impairs the absorption of iron and zinc from the digestive tract ().
Therefore, heavy consumption of peanuts may contribute to deficiencies in these minerals over time.
Phytic acid is usually not a concern in well-balanced diets and among those who eat meat regularly. On the other hand, it may be a problem in developing countries where the main food sources are grains or legumes.
Bottom Line: Peanuts contain phytic acid, which impairs the absorption of iron and zinc.
Peanuts are one of the 8 most common food allergens.
Allergy to peanuts is estimated to affect approximately 1% of Americans ().
Peanut allergies may be severe, potentially life-threatening, and peanuts are sometimes considered to be the most severe allergen ().
People with peanut allergy should avoid peanuts and peanut products.
Bottom Line: Many people are allergic to peanuts and need to avoid them. Peanut allergy can be life-threatening in severe cases.
Peanuts are as popular as they are healthy.
They are an excellent plant-based source of protein, and are high in various vitamins, minerals and plant compounds.
They can be useful as a part of a weight loss diet, and may reduce the risk of both heart disease and gallstones.
However, being high in fat, peanuts are a high-calorie food and should not be eaten in excess.