What Happens if You Eat Walnuts Every Day? Benefits, How Many, and Side Effects

  • Medical Reviewer: Dany Paul Baby, MD
Medically Reviewed on 9/26/2022

Walnut nutrition

Walnuts are among the most health-enhancing foods you can eat regularly. Eating an ounce of walnuts every day reduces your risk of heart disease and they are full of proteins, calories, and healthy fats.
Walnuts are among the most health-enhancing foods you can eat regularly. Eating an ounce of walnuts every day reduces your risk of heart disease and they are full of proteins, calories, and healthy fats.

Walnuts are among the most health-enhancing foods you can eat regularly. They're easy to carry and can be consumed whenever you have a few minutes. Walnut benefits include improved heart health, lowered low-density lipoprotein (LDL, "bad cholesterol"), and a boost in protein, fiber, vitamins, and minerals. These nuts provide several antioxidants and anti-inflammatory compounds that slow down aging and degenerative changes.

Walnuts have a lot of beneficial nutrients. A 100-gram portion of walnuts provides:

Energy: 654 calories

Protein: 15.2 grams

Total fats: 65.2 grams

Saturated fatty acids: 6.1 grams

Monounsaturated fatty acids: 8.9 grams

Polyunsaturated fatty acids: 47.2 grams

Fiber: 6.7 grams

Carbohydrates: 13.7 grams

Minerals: Calcium, iron, magnesium, phosphorus, sodium, potassium, zinc, copper, manganese, and selenium.

Vitamins: Vitamins A, C, E, and K, and several of the B vitamins.

At first glance, the fat content is alarming. But less than 10% of the total fats are saturated fatty acids that increase your blood cholesterol levels. Most of the fat is polyunsaturated fatty acids that are beneficial for health.

Walnut benefits your heart

Walnuts are packed with heart-healthy nutrients. Eating 30 to 60 grams of walnuts daily reduces your total cholesterol, low-density lipoprotein, and intermediate-density lipoprotein cholesterol. LDL is considered the "bad cholesterol" that increases your risk of heart disease. Even if you're already taking statin drugs for cholesterol reduction, walnuts can further reduce your blood LDL levels. People with hypercholesterolemia benefit more from eating walnuts.

These chemical benefits translate to better health. People who eat walnuts regularly have fewer heart attacks and a lower risk of dying from heart disease. Eating nuts several times a week lowers your risk of sudden cardiac death, myocardial infarction, and cardiovascular disease by a remarkable 30% to 50%.

The unsaturated fats in walnuts not only lower LDL but also increase high-density lipoprotein (HDL) cholesterol (the "good cholesterol") blood levels. Walnuts are also rich in omega-3 fatty acids that protect against arrhythmia (irregular heart rhythms) and blood clots.

People with type 2 diabetes mellitus (T2DM) are at high risk for heart disease and stroke. Eating about an ounce of nuts five times a week reduces the risk of high cholesterol blood levels, heart disease, and premature death.

Walnuts are also a good source of dietary fiber. Consuming dietary fiber reduces your risk for metabolic syndrome and heart disease. Including fiber in your diet also improves your digestive health.

Walnuts and your brain

Walnuts protect you from the age-associated decline in mental function, Alzheimer's disease, mild cognitive impairment (MCI), and other brain disorders. Many of these disorders result from oxidative stress and inflammation in the nervous system. Walnuts have several compounds with potent antioxidant effects, including gamma tocopherol, melatonin, flavonoids, phenolic acid, and proanthocyanidins.

Walnuts also contain alpha-linolenic acid (ALA), an essential fatty acid with powerful anti-inflammatory actions. ALA suppresses inflammatory molecules like interleukins and tumor necrosis factor-alpha (TNF-α). ALA is converted to eicosapentaenoic acid (EPA) and docosahexaenoic acid (DHA), which also have anti-inflammatory effects. Eating walnuts regularly can reduce your risk of dementia and slow its progress.

Including walnuts in your daily diet can help you avoid age-associated decline in memory, learning, judgment, orientation, language, and comprehension. Such effects of aging affect everyday life and social function. Eating walnuts preserves memory, learning, and processing speed.

Should you eat walnuts?

Certainly, you should. Besides proteins, calories, and healthy fats, nuts are rich in arginine. This amino acid enables the body to make nitric oxide, a molecule that relaxes narrowed blood vessels and improves blood flow. Nuts are also good sources of vitamin E, folate, fiber, and other valuable nutrients. Nuts all have a different mix of these nutrients, so it may be best to include a variety of nuts in your diet.

The American Heart Association considers legumes and nuts healthy sources of protein. Diets dependent only on meat for protein are considered unhealthy now, and the recommendation is to replace meat partially with plant-source protein. Walnuts are especially valuable because of their high concentration of polyunsaturated fatty acids. These are better than monounsaturated fatty acids at protecting your heart by reducing serum lipid concentrations.

Walnuts have the highest phenolic content among nuts. This gives them excellent antioxidant activity, protecting your cells and organs from damage by free radicals. A 50-gram portion of walnuts has more phenolic content than a glass of red wine or apple juice.

Among all nuts, walnuts are unique for their high content of the polyunsaturated fatty acids ALA and linoleic acid. Most nuts are rich in monounsaturated fatty acids. Eating walnuts every day reduces your blood pressure and blood levels of total cholesterol, triglycerides, low-density lipoprotein (LDL), and apolipoprotein B, protecting your heart.

Walnuts also contain fiber, which is good for digestive health and prevents colon cancer. Fiber also reduces your risk of heart disease by preventing the absorption of fat and cholesterol. If you have diabetes or prediabetes, having enough fiber in your food prevents blood sugar spikes after meals.


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Health risks of walnuts

Calorie overload. Walnuts are packed with energy. A hundred-gram portion of walnuts has 654 calories and can potentially overload you with calories. Excess calories are an obesity risk.  

Allergy. Among the tree nuts, walnuts and cashews most frequently cause allergic reactions in America. Allergies to walnuts can appear as skin rashes, digestive problems, or respiratory symptoms like cough and wheezing. The most severe form of allergy is anaphylaxis, which causes breathing difficulty, falling blood pressure, and sometimes death. Walnut allergy usually appears in childhood and persists throughout life.

How many walnuts a day?

Walnuts are tasty and healthy, but you should eat them carefully. Eating a hundred grams of walnuts will add 654 calories to your daily intake. This will make it difficult to include enough foods from the other major food groups in your diet. 

An ounce (30 grams) of walnuts a day has been shown to reduce the risk of heart disease. The recommended serving size is a small handful or 1½ ounces (45 grams) a day. Walnuts make an excellent nutrient-dense snack, and you can easily carry them wherever you go.

Medically Reviewed on 9/26/2022

Advances in Nutrition: "Plant-Based Dietary Patterns, Plant Foods, and Age-Related Cognitive Decline."

Centers for Disease Control and Prevention: "Fiber: The Carb That Helps You Manage Diabetes."

Circulation: "2021 Dietary Guidance to Improve Cardiovascular Health: A Scientific Statement From the American Heart Association," "Effects of Walnut Consumption for 2 Years on Lipoprotein Subclasses Among Healthy Elders."

Harvard TH Chan School of Public Health: "Nuts for the Heart."

Journal of the American Heart Association: "Replacing Saturated Fat With Walnuts or Vegetable Oils Improves Central Blood Pressure and Serum Lipids in Adults at Risk for Cardiovascular Disease: A Randomized Controlled-Feeding Trial."

Nutrients: "Beneficial Effects of Walnuts on Cognition and Brain Health," "Nut Allergy: Clinical and Allergological Features in Italian Children."

US Department of Agriculture: "Nuts, walnuts, english."