Cashews are a nutrient-dense nut packed with copper, magnesium, and plant protein, offering measurable benefits for heart health, bone strength, and everyday nutrition. A single ounce (about 18 kernels) delivers over 5 grams of protein, 83 milligrams of magnesium, and 0.62 milligrams of copper, which is roughly 70% of the daily value for that mineral. Few foods match that copper concentration, and it makes cashews uniquely valuable beyond their reputation as a snack.
What’s in a Handful of Cashews
One ounce of raw cashews contains about 157 calories, 5.2 grams of protein, and 168 milligrams of phosphorus. The fiber content is modest at just under 1 gram per ounce, so cashews aren’t your best bet for digestive fiber the way almonds or pistachios might be. Where they stand out is in mineral density. That 83 milligrams of magnesium per ounce covers roughly 20% of most adults’ daily needs, and the copper content is unusually high for a common food.
The fat in cashews is predominantly unsaturated. About 62% of it is monounsaturated fat, the same type found in olive oil and avocados. Compared to other tree nuts, cashews are actually lower in total fat, which is partly why traditional calorie estimates for them have been found to overstate the energy your body actually absorbs by 5 to 21%, according to USDA research. In practical terms, a handful of cashews likely delivers fewer usable calories than the nutrition label suggests.
Heart Health and Cholesterol
The strongest evidence for cashews falls under cardiovascular health. A large meta-analysis of 113 randomized controlled trials, covering over 8,000 adults, found that regular nut consumption reduced LDL (“bad”) cholesterol by an average of 0.12 mmol/L and total cholesterol by 0.14 mmol/L. Triglycerides dropped modestly as well. The median intake across these studies was about 45 grams per day, or roughly 1.5 ounces.
These aren’t dramatic swings, but they’re consistent and statistically significant across different populations, including people with diabetes and those with elevated cholesterol at baseline. The ratio of total cholesterol to HDL cholesterol also improved, which is a more meaningful predictor of heart disease risk than any single cholesterol number. One thing the data didn’t show: nut consumption had no significant effect on HDL (“good”) cholesterol levels on its own.
Why Copper Matters More Than You Think
Copper doesn’t get the attention that iron or calcium does, but it plays a critical role in several body systems. It acts as a cofactor for enzymes involved in iron metabolism, collagen production, and bone mineralization. One enzyme in particular, lysyl oxidase, depends on copper to cross-link collagen fibers. Without adequate copper, collagen loses structural integrity, which weakens bones, connective tissue, and blood vessels.
Copper also helps normalize calcium and phosphorus deposition in bones, making it essential for maintaining bone density over time. Cashews are one of the richest common dietary sources of copper, alongside liver and seafood. If you don’t eat organ meats regularly, cashews are one of the most accessible ways to keep your copper intake where it needs to be.
Magnesium for Muscles and More
Magnesium is involved in over 300 enzymatic reactions in the body, from muscle contraction and nerve signaling to blood sugar regulation and blood pressure control. Surveys consistently show that most adults in the U.S. fall short of the recommended daily intake. At 83 milligrams per ounce, cashews are a practical way to close that gap without supplements.
Low magnesium intake is associated with higher rates of type 2 diabetes, high blood pressure, and osteoporosis. Getting enough magnesium from food sources like cashews, leafy greens, and whole grains is generally more effective and better tolerated than relying on supplements, which can cause digestive issues at higher doses.
Blood Sugar: What the Evidence Actually Shows
You’ll find claims that cashews help manage blood sugar, but the clinical evidence is lukewarm. A meta-analysis of six randomized controlled trials with 521 participants found that incorporating cashews into the diet had no significant effect on fasting blood sugar, insulin levels, or insulin resistance scores. One smaller trial did find a reduction in fasting insulin after participants ate 30 grams of cashews daily for eight weeks, but blood sugar itself didn’t change meaningfully.
This doesn’t mean cashews are bad for blood sugar. Their combination of protein, fat, and relatively low carbohydrate content means they won’t spike your glucose the way refined carbs would. They’re a smart snack choice if you’re watching your blood sugar, but they’re not a therapeutic tool for managing diabetes on their own.
Mood and Brain Function
Cashews contain tryptophan, an amino acid your body uses to produce both serotonin and melatonin. Serotonin regulates mood, appetite, and sleep, while melatonin governs your sleep-wake cycle. Nuts and seeds as a group are considered excellent dietary sources of tryptophan, and cashews also supply zinc and selenium, two minerals linked to proper brain function and lower rates of depression.
This is a case where the mechanism is well understood but the direct clinical evidence for cashews specifically is limited. Eating cashews won’t replace treatment for a mood disorder, but regularly including tryptophan-rich foods in your diet supports the raw material your brain needs to produce key neurotransmitters.
Calorie Reality and Weight
At roughly 157 calories per ounce on paper, cashews seem calorie-dense. But your body doesn’t extract every calorie listed on the label. USDA research has shown that traditional methods of estimating calories in tree nuts overstate the actual energy value by anywhere from 5 to 21%. The fat in cashews is partially trapped within the nut’s cell walls, and some of it passes through your digestive system without being fully absorbed.
This means cashews are a better weight management snack than their calorie count suggests. Their protein and fat content also promotes satiety, helping you feel full longer compared to an equal-calorie serving of crackers or pretzels.
Oxalates and Kidney Stones
If you’re prone to calcium-oxalate kidney stones, cashews deserve a note of caution. One ounce contains about 49 milligrams of oxalates, which puts them in the “very high” category. Oxalates bind with calcium in the kidneys and can contribute to stone formation in susceptible people. This doesn’t make cashews dangerous for the general population, but if you’ve had kidney stones before, you may want to moderate your intake and pair cashews with calcium-rich foods, which can bind oxalates in the gut before they reach the kidneys.
Why Cashews Are Never Sold in the Shell
Cashews belong to the same plant family as poison ivy and poison sumac. Between the two layers of the cashew shell sits an oily resin that can blister skin on contact. This is why you’ll never find raw, in-shell cashews at a grocery store. During processing, the shells are roasted at high temperatures to neutralize the caustic compounds, and the resin is burned off before the edible kernel inside is extracted. By the time cashews reach store shelves, the irritant has been completely removed. Even “raw” cashews sold commercially have been steamed or briefly heated to make them safe to handle and eat.