Peanuts & Cancer

Peanuts don’t just have one nutrient that can help in preventing cancer; they have many! Unsaturated fats, certain vitamins & minerals, and many bioactives with cancer-preventing qualities are all packaged into one peanut kernel. It may seem crazy to think that peanuts and peanut butter fight cancer, but research has proven that there are many cancer-preventive factors that contribute to a reduced risk for cancer.

Currently the second-leading cause of death in the United States, cancer is a disease that causes abnormal cells to divide uncontrollably and can invade nearby tissues. Cancer affects millions of lives every year and peanuts can deliver a punch. Multiple studies have found associations between nut consumption and reduced risk of cancer mortality.

There are many types of cancer that target different parts of the body, but components in peanuts may work individually or together, and in different ways, to prevent the progression of this complex disease.

Breast Cancer Study

A 2015 study found that a high consumption of nuts, including peanuts, was associated with 2-3 times reduced risk of breast cancer. This study was published in Gynecologic and Obstetric Investigation and compared 97 breast cancer cases to 102 normal cases in Mexico. Researchers found that a high consumption of nuts including peanuts was associated with 2-3x reduced risk of breast cancer.

The Netherlands Cohort Study followed 120,852 men and women for 20.3 years.

Researchers examined the association between diet and cancer. They found that peanut consumption was associated with a reduced risk of estrogen negative breast cancer—the type that is harder to treat. Further, for participants who consumed 10g a day or more, total nut intake decreased risk of estrogen negative breast cancer.

It has also been found that increasing peanut intake early on also helps young girls with the prevention of the risk of benign breast disease (BBD). A study conducted in 2010 produced the following results: It has also been found that increasing peanut intake early on also helps young girls with the prevention of the risk of benign breast disease (BBD). A study conducted in 2010 produced the following results:

• Results were seen with just two servings a week of peanut butter or peanuts. Young girls who consumed a serving of peanut butter or peanuts at least twice a week reduced their risk of benign breast disease (BBD) in young adulthood by up to 39%.
• First study to look at reported dietary intakes prospectively reported by adolescent girls. Previous studies from dietary recalls by adults later in life have shown that peanuts consumed in high school lowered the risk of BBD by one-third, and other nuts required twice the amount to have the same effects.
• Peanut butter and peanuts were more effective than other vegetable proteins. In the study, beans, lentils, soy, vegetable oil, green beans, and broccoli were not significant in reducing risk, whereas peanut butter and peanuts were highly significant.
• Peanut butter was protective for all ages. Peanut butter, high in plant protein and vegetable fat, was shown to reduce the risk of BBD at any age in the study.
• Vegetable protein intake, from peanut butter and peanuts, was protective for 14-year-old girls. Cumulative vegetable protein intake, mainly due to peanut butter and peanuts, decreased the risk of BBD in 14-year-old girls.
• Vegetable fat intake, from peanut butter and peanuts, was protective for 11-year-old girls.
• Cumulative vegetable fat intake, mainly due to peanut butter and peanuts, was shown to decrease the risk of BBD in 11-year-old girls by up to 44%.
• Results were most significant with girls who had a family history of breast cancer. Higher intakes of all vegetable fat, mostly from peanut butter and protein, significantly decreased the risk of BBD. In addition, benefits against BBD were shown for peanut butter and peanut consumption before and after the onset of menses.
• Pre-adolescent and adolescent years may represent a critical age for prevention. Breast development and changes in hormonal environment at ages 11-14 make adolescence a critical time period for reducing risks of breast cancer with improved dietary choices, such as including peanut butter or peanuts twice a week.

Peanuts & Colon Cancer (Colorectal Cancer)

The amount of seeds and nuts (including peanuts) we eat may also help to reduce our risk of colon cancer. Through a large population analysis in Europe known as the European Prospective Investigation into Cancer and Nutrition study, it was found that women who consumed the highest quantities experienced the lowest risks.

In a separate 2019 subgroup analysis, authors examined the impact of 12 major food groups (including nuts) on colon cancer risk. Their findings also saw greater nut consumption coincide with a reduced risk of colon cancer.

Esophageal Cancer

In parts of Iran and China, esophageal cancer is seen in high rates—ranking as the 10th most common malignancy in China.

Researchers from the Golestran Cohort Study in Iran enrolled over 50,000 participants from over a four-year period to examine the relationship between nut intake and esophageal cancer. Participants who consumed the most nuts showed a 40% reduced risk of esophageal cancer compared to those who consumed none.

Researchers from the Yanting Cancer Hospital in China conducted a 2017 case-control study examining peanuts specifically. They observed that peanut consumption 1-3 times per week reduced esophageal cancer risk by 38%, while consumption 4 or more times per week lowered risk by 70%. In their conclusion, they noted that peanut production and consumption “should be promoted in high-risk areas in order to reduce the ESCC (esophageal cancer) burden.”

Pancreatic Cancer

Pancreatic cancer is the 7th leading cause of cancer mortality worldwide. The Netherlands Cohort Study, which followed 120,852 men and women for over 20 years, evaluated the relationship between peanuts and pancreatic cancer. They found that consuming 5g (1 teaspoon) or more of peanut butter daily was associated with a significantly reduced risk of pancreatic cancer in men. A previous 2013 study from Harvard University showed that women who consumed peanuts/tree nuts 2 times or more per week had up to a 35% reduction in pancreatic cancer risk compared to those who consumed none.

A 2014 study reviewing the evidence surrounding nut consumption and cancer noted that several components in nuts like peanuts work in a synergistic way to block cancer cell proliferation. Further, some of the compounds may also act as antioxidants and anti-inflammatory agents. Two of the compounds that play a role are phytosterols and resveratrol.

Prostate Cancer

While the relationship between prostate cancer risk and peanut consumption has not yet been fully explored, a number of studies have shown promising results. In 2017, authors of a study extracted resveratrol from peanut stems to test the effectiveness of each on radiation-resistant prostate cancer cells. Their results showed that both resveratrol and peanut stems inhibited the growth of radiation-resistant prostate cancer cells. They also reported a synergistic effect, where combining irradiation with resveratrol or peanut stems dramatically inhibited tumor growth.

In the following year, another study looked at the effect of treating prostate cancer cells with procyanidins (a flavonoid) from peanut skins. The results showed that the procyanidins induced cancer cell death and prevented cancer cells from growing, leading the authors to conclude that it “[has] the potential to be developed as an anti-prostate cancer agent.”

Nutrients Working Together

A review of studies noted that several components found in peanuts reduce cancer risk. These components work in a synergistic way to block cancer cell development.3 Two compounds with anticancer properties are phytosterols and resveratrol.

Phytosterols

Phytosterols are natural chemicals found in plants. Phytosterols are found in high concentrations in some plant oils, seeds and legumes, such as peanuts. They are also found in lower concentrations in fruits and vegetables. Recent research has shown that phytosterols inhibit cancer growth, protect against heart disease, and may offer protection from colon, prostate and breast cancer.

Phytosterols (PS) are literally plant (phyto) chemicals. They include both plant sterols and plant stanols, which differ in their chemical structures. The three most common forms of phytosterols in foods are beta-sitosterol, campesterol, and stigmasterol.

The relationship between phytosterols and cancer have been extensively studied. Evidence suggests that they may prevent cancer cells from growing and spreading and may cut off the blood flow to cancers inhibiting lung, stomach, ovarian, prostate, colon, and breast cancers. One of the main phytosterols in peanuts is called beta-sitosterol, which offers protection from colon, breast, and prostate cancers. Researchers at the State University of New York at Buffalo found that phytosterols can reduce prostate tumor growth by over 40% and decrease the chances of cancer spreading to other parts of the body by almost 50%.

Epidemiological and experimental evidence suggests phytosterols have a protective effect. Long-term studies show an association between the amount of plant sterol consumed in the diet and developing cancer. For example, there is a much higher incidence of colon, prostate, and breast cancers in Western societies as compared to Asian societies, where they consume more than 3-4 times the amount of phytosterols. The Western diet contains approximately 80 mg PS/day, whereas vegetarian diets contain 345 mg PS/day and Japanese diets contain 400 mg PS/day.3 

In an experimental study recently published in Anticancer Research, mice with human cancer tumors were fed either a phytosterol diet or a cholesterol diet. Tumor size in animals fed the phytosterols was 33% smaller and had 20% fewer shifts of cancer cells to lymph nodes and lungs than in the cholesterol diet group.1 The article concludes, “Phytosterols, which can be easily incorporated into our diet, may offer a relatively simple and practical means for retarding growth and metastases of breast cancer cells.” Peanuts are also one of the few foods that contain the plant chemical resveratrol. This sterol has been associated with reduced cardiovascular disease and reduced cancer risk. Resveratrol is most widely known for its presence in grape skins and red wine, and may be one of the compounds responsible for the health benefits of red wine consumption. Dr. Tim Sanders and his team of researchers at the US Department of Agriculture found that peanuts have a significant amount of resveratrol. The average amount of resveratrol in one ounce of commonly eaten peanuts without the skin (15 whole peanut kernels) is 73 ug.4,5 Ounce for ounce, peanuts contain almost 30 times as much resveratrol as grapes.

Resveratrol

Resveratrol is another compound found in peanuts that has anti-cancer properties. Resveratrol is naturally found in plants to protect them from disease, injury, or fungal infection. It is part of a category of plant chemicals that are called “phytoalexins.” “Phyto” means plant in Greek, while “alexin” means “to ward off” or to protect. The compound is produced by and found in the roots, stems, leaves, shells, and seeds of peanut plants. That means it’s in peanut butter too. Familiar to most because of its presence in red wine and grape skins, resveratrol has been called the “life-extending” phytochemical. Researchers are referring to it as the first major anti-aging compound.

Like phytosterols, resveratrol has been shown to cut off the blood supply to growing cancers and to inhibit cancer cell growth. In recent studies, it has shown promise in helping fight breast, lung, colorectal, prostate, brain and bladder cancers. A 2017 study observed that resveratrol accomplishes this in breast cancer by preventing cancerous cell invasion. With a number of bioactives helping to prevent disease and promote health, peanuts can help pack a punch to fight cancer!