Do Peanuts Reduce the Risk of Heart Disease?
Almost two decades ago, research pointed to the fact that frequently eating peanuts reduces the risk of heart disease. The effects are evident for people of all ages and genders, and even for individuals with various conditions, such as diabetes.
Heart disease is the leading cause of death in the United States and many parts of the world. It is associated with various complications including atherosclerosis, or the build-up of plaque in the walls of arteries. This build-up can narrow the arteries and make it hard for blood to flow through, possibly leading to blood clots, heart attack or stroke.
A 2018 review in Current Atherosclerosis Reports found that nut consumption doesn’t just reduce the risk of dying from heart disease; but eating peanuts also reduces high blood pressure, high cholesterol, and helps keep blood vessels healthy.
Another review published in Progress in Cardiovascular Diseases included 25 years of research and showed a strong association between nut intake and decreased risk of fatal and non-fatal coronary heart disease, myocardial infarction, and sudden death. The authors noted that the unsaturated fats, l-arginine, minerals, phenolic compounds and phytosterols in nuts like peanuts appear to be of “paramount importance” for their health effects. They also highlighted that an “estimated 8.3% reduction in risk from coronary heart disease death ensues from each weekly serving (about 30g) of nuts.”
Other studies have found evidence pointing to additional components playing a part in peanuts’ heart-protective powers. Arginine, like that found in peanuts, may improve circulation and reduce heart disease risk. Peanuts are also a good source of vitamin E, which, when consumed in low quantities, can lead to benefits against coronary heart disease.
Peanuts can lower LDL & Triglycerides
Peanuts, peanut butter, and peanut oil are filled with heart-healthy monounsaturated and polyunsaturated fats. These fats lower total and “bad” LDL cholesterol as well as triglyceride levels, while keeping “good” HDL cholesterol high. A controlled study of people eating diets high in either peanut oil, peanuts and peanut butter, or olive oil, all of which are high in monounsaturated fat (MUFA), showed that levels of total cholesterol, bad LDL cholesterol, and triglycerides were lowered, while good HDL cholesterol levels remained high.
Peanuts have low amounts of saturated fat, which is found in many animal products, and have no trans fat at all. A 2001 study by the U.S. Department of Agriculture found that levels of trans fat are non-detectable in all types of peanut butter—even the creamy kind.
After much scientific evidence regarding the positive health benefits of peanuts and nuts, the U.S. Food and Drug Administration released a report in 2003 that states, “Scientific evidence suggests but does not prove that eating 1.5 ounces of most nuts, such as peanuts, as part of a diet low in saturated fat and cholesterol may reduce the risk of heart disease.”
Peanuts can lower blood pressure
Studies also show that including peanuts in your diet as a source of protein lowers blood pressure, which can decrease heart disease risk. Peanuts have a unique mix of functional components, vitamins, and minerals that help the body prevent heart disease. Eating peanuts and peanut butter isn’t just delicious—it makes your heart happy, too!
Phytosterols in Peanuts Can Lower Cholesterol
Traditionally, scientists have looked at plant sterols for their benefits in preventing heart disease. Phytosterols were first recognized in the 1970’s for their ability to absorb dietary cholesterol in the blood, thereby protecting against cardiovascular disease.
Phytosterols lower cholesterol in two ways. First, they block the absorption of dietary cholesterol that is circulating in the blood. Secondly, they reduce the reabsorption of cholesterol from the liver, which your body naturally produces. So whether your cholesterol is high because of dietary habits, genetics, or both, eating foods with phytosterols can help lower blood cholesterol levels.
Food companies have started adding different plant sterols and plant stanols to foods.
Peanuts and peanut products are unique whole foods that naturally contain phytochemicals. They also contain heart healthy monounsaturated fat, which has been linked to lowering blood cholesterol levels.
A recent study from Penn State University shows that diets that include 2-3 servings daily of peanuts or peanut butter lowered cholesterol by 11-14%. The researchers compared three higher fat diets—one with peanuts and peanut butter, the second with peanut oil, and the third with olive oil—to the average American diet and a low-fat diet. They found that the three diets rich in monounsaturated fat all lowered total cholesterol, LDL (bad) cholesterol, and triglyceride levels, and did not lower beneficial HDL cholesterol levels.
One factor that might contribute to these results, in addition to other essential nutrients and healthy fatty acids, are the many plant chemicals found in peanut products. Overall, the peanut diets reduced the risk of cardiovascular disease by 21%, whereas a low-fat diet reduced the risk by only 12%.
Peanut protein and bioactives help keep arteries healthy
An exciting study from Penn State University demonstrates one way in which peanuts are heart healthy. This study shows that eating peanuts can help keep your arteries flexible.
- First study to show that peanut protein and bioactives help keep arteries flexible
- Peanuts prevent arteries from stiffening after a high-fat meal
- After high-fat meals, peanuts reduce the rise in triglyceride levels by 32%
The human body has up to 100,000 miles of arteries, veins and capillaries. These blood vessels carry oxygen and nutrients throughout the body and must remain flexible in order to work properly.
After a high-fat meal, levels of fat in the blood tend to rise rapidly, causing blood vessels to become stiff. Over time, this stiffening causes the heart to work harder, increasing the risk of heart attack and stroke.
In this study, participants who ate peanuts as part of a high-fat shake reduced the rise in blood triglycerides by 32% compared to a control shake. The control and peanut shakes were carefully designed to have the same fatty acid profile; therefore researchers attribute this response to peanut protein and bioactives.
Remarkably, peanuts also caused the participants’ arteries to remain open and flexible, despite the shake deriving 50% of its calories from fat.
Peanut Protein and Bioactives
Peanut protein, along with bioactives, vitamins & minerals, likely play a major role in preventing this stiffening response. Peanuts contain more protein than any other nut and more arginine than almost all other foods.
This is important because arginine is used to make nitric oxide, a vasodilator that helps keep blood vessels open and elastic.
This study is unique because it is the first to show that peanut protein and bioactives work together to keep arteries flexible after a high-fat meal.
Decades of research show that the healthy mono- and polyunsaturated fats in peanuts lower blood cholesterol and significantly reduce the risk of heart disease. Peanuts received a Food and Drug Administration (FDA) Qualified Health Claim for Heart Health in 2003, and peanuts are also included on the list of foods certified by the American Heart Association’s Heart-Check program.
Inflammation and Cardiovascular Disease
The search for new and more consistent predictors of cardiovascular disease (CVD) has led researchers to find out more about inflammation. Inflammation can be defined as a natural response from the body to intruders. For instance, when you cut your skin, get a bruise, or catch a cold, your immune system kicks in and calls for help, resulting in inflammation.
Researchers are discovering that fat cells, once thought to be dormant, make a unique contribution to immune function, thereby influencing disease status. While basic inflammation is a normal, healthy response, trouble arises when the body is in a chronic state of heightened immunity. In a sense, the body begins to fight itself. Abnormal inflammation could occur in obese people where there tends to be a surplus of fat tissue containing fat cells. As fat mass increases, stress response in the body increases, resulting in chronic inflammation. This might help explain why obesity is a risk factor for a number of diseases, including arthritis, diabetes, and heart disease.
Although the puzzle is not yet complete, the markers for inflammation are known. They include C-reactive protein (CRP), interleukin 6 (IL-6) and tumor necrosis factor (TNF).
Powerful substances like interleukin 6 and TNF help to regulate the immune system, but CRP has been identified as the key marker for inflammation. Data indicates that the proportion of cardiovascular disease (CVD) that might be prevented by reducing inflammation may be even greater than could be achieved by reducing low-density lipoprotein (LDL) cholesterol in the population. CRP is influenced by many variables, including those within our control, such as diet and exercise.
Researchers are beginning to discover that what you eat and drink and how active you are affects biomarkers, like CRP, that predict inflammation. For example, a Western diet pattern (higher in red meat, high-fat dairy products, and refined grains) has been shown to increase CRP. In addition, chronic diseases such as diabetes and obesity appear to be linked to elevated CRP levels.
Trans Fat and CRP
In a study of data from the Harvard School of Public Health’s Nurses’ Health Study, researchers examined the relationship between trans fat consumption and inflammatory markers. After analyzing the diets of over 820 healthy women, the researchers concluded that trans fat intake was positively associated with markers of systematic inflammation in women. Further, there was a positive association between trans fat intake and CRP and IL-6 in women with a higher body mass index (BMI).
Fiber Intake and CRP
An examination of the US National Health and Nutrition Examination Survey (NHANES) from 1999-2000 shows that subjects in the third and fourth highest quartiles of fiber consumption (13.3-19.5 and >19.5 grams per day, respectively) had a lower risk of elevated CRP compared to those in the lowest quartile (less than 8.4 grams per day). This association was present even after controlling for variables such as body mass index, smoking, exercise, total calorie intake, and alcohol consumption. This finding suggests that inflammation may be one of the links between cardiovascular disease and diet quality.
Magnesium and CRP
In a cross sectional study of 371 subjects, researchers showed that serum magnesium levels were independently related to CRP concentration. Further, in this study, the lowest serum magnesium levels and the highest CRP concentrations were documented in the obese subjects.
Metabolic Syndrome and CRP
Metabolic syndrome is often described as the crossroad between diabetes and heart disease because the predictors and symptoms overlap with both diseases. Many of the characteristics of metabolic syndrome are risk factors associated with either type 2 diabetes or heart disease, or both. According to the US National Cholesterol Education Program (NCEP) guidelines, metabolic syndrome includes risk factors such as:
- High blood pressure
- Low “good” HDL cholesterol
- Elevated triglycerides
- Too much abdominal fat
In the Framingham Offspring Study, researchers examined the relationship of CRP levels to metabolic syndrome in 3037 subjects over 7 years. They concluded that elevated CRP levels are related to insulin resistance and the presence of metabolic syndrome. Both elevated CRP and metabolic syndrome are independent predictors of new cardiovascular events.
Diabetes and CRP
Research suggests that elevated CRP may predict an increased risk of developing type 2 diabetes. Several studies have shown that both CRP and IL-6 levels in the blood predict insulin resistance and type 2 diabetes. In a study of more than 32,000 women, those with the highest levels of CRP had the greatest risk for developing type 2 diabetes.
Weight Loss and CRP
What is clear from current scientific research is that overweight and obese individuals are at greater risk for many chronic diseases. Inflammation and CRP levels may help to explain in part this added risk. Research is ongoing to pinpoint the exact function of fat cells and why they seem to be so harmful to health.
Scientists now know that fat cells do a lot more than just store energy. In fact, they perform many important functions in the body. Fat cells play a crucial role in sending out chemical signals that regulate functions such as constriction of blood vessels, production of sex hormones, immune response, and more. In large population studies, CRP has been positively associated with body weight and body fatness. A clinical study that examined obese women found that restricting calories, and thereby inducing weight loss, decreased plasma CRP levels. Further, the weight-loss program had additional metabolic benefits. Those who lost weight in the study also increased good HDL cholesterol concentrations, decreased triglyceride levels and decreased their total cholesterol /HDL cholesterol ratio. When overweight people lose weight, CRP consistently goes down (13).
According to a large body of research, weight loss of 5 to 15 percent of body weight has proven health benefits (14). This is the equivalent of a 200-pound person losing 10 to 30 pounds.
Overall, emerging research shows that diet can play a role in controlling new predictors of cardiovascular disease (CVD), including inflammation. The good news is that many chronic diseases, such as CVD, can be prevented with the same healthful diet. Namely, one that is calorie-controlled, balanced in protein, “good” unsaturated fat, and “good” carbohydrates, and full of fruits, vegetables, whole grains, nuts and peanuts.