What Are Nuts?
Nuts are seed kernels that are widely used in cooking or eaten on their own as a snack. They’re high in fat and calories.
They contain a hard, inedible outer shell that usually needs to be cracked open to release the kernel inside.
Fortunately, you can buy most nuts from the store already shelled and ready to eat.
Here are some of the most commonly consumed nuts:
Though peanuts are technically legumes like peas and beans, they’re usually referred to as nuts due to their similar nutrition profile and characteristics.
1. A Great Source of Many Nutrients
Nuts are highly nutritious. One ounce (28 grams) of mixed nuts contains:
Some nuts are higher in certain nutrients than others. For instance, just one Brazil nut provides more than 100% of the Reference Daily Intake (RDI) for selenium.
The carb content of nuts is highly variable. Hazelnuts, macadamia nuts, and Brazil nuts have fewer than 2 grams of digestible carbs per serving, while cashews have almost 8 digestible carbs per serving.
That being said, nuts are generally an excellent food to eat on a low-carb diet.
2. Loaded With Antioxidants
Nuts are antioxidant powerhouses.
Antioxidants, including the polyphenols in nuts, can combat oxidative stress by neutralizing free radicals — unstable molecules that may cause cell damage and increase disease risk.
One study found that walnuts have a greater capacity to fight free radicals than fish.
Research shows that the antioxidants in walnuts and almonds can protect the delicate fats in your cells from being damaged by oxidation.
In one study in 13 people, eating walnuts or almonds increased polyphenol levels and significantly reduced oxidative damage, compared to a control meal.
Another study found that 2–8 hours after consuming whole pecans, participants experienced a 26–33% drop in their levels of oxidized “bad” LDL cholesterol — a major risk factor for heart disease.
However, studies in older people and individuals with metabolic syndrome found that walnuts and cashews didn’t have a big impact on antioxidant capacity, though some other markers improved.
3. May Aid Weight Loss
Though they’re considered a high-calorie food, research suggests that nuts may help you lose weight.
One large study assessing the effects of the Mediterranean diet found that people assigned to eat nuts lost an average of 2 inches (5 cm) from their waists — significantly more than those given olive oil.
Almonds have consistently been shown to promote weight loss rather than weight gain in controlled studies. Some research suggests that pistachios aid weight loss as well.
In one study in overweight women, those eating almonds lost nearly three times as much weight and experienced a significantly greater decrease in waist size compared to the control group.
What’s more, even though nuts are quite high in calories, research shows that your body doesn’t absorb all of them, as a portion of fat stays trapped within the nut’s fibrous wall during digestion.
For instance, while the nutrition facts on a package of almonds may indicate that a 1-ounce (28-gram) serving has 160–170 calories, your body only absorbs about 129 of these calories.
Similarly, recent studies found that your body absorbs about 21% and 5% fewer calories from walnuts and pistachios, respectively, than had previously been reported.
4. May Lower Cholesterol and Triglycerides
Nuts have impressive effects on cholesterol and triglyceride levels.
Pistachios have been shown to lower triglycerides in people who are obese and those with diabetes.
In one 12-week study in obese people, those eating pistachios had triglyceride levels nearly 33% lower than in the control group.
The cholesterol-lowering power of nuts may be due to their high content of monounsaturated and polyunsaturated fatty acids.
Almonds and hazelnuts appear to raise “good” HDL cholesterol while reducing total and “bad” LDL cholesterol. One study found that ground, sliced, or whole hazelnuts had similar beneficial effects on cholesterol levels.
Another study in women with metabolic syndrome observed that eating a 1-ounce (30-gram) mix of walnuts, peanuts, and pine nuts per day for 6 weeks significantly lowered all types of cholesterol — except “good” HDL.
Several studies show that macadamia nuts lower cholesterol levels as well. In one trial, a moderate-fat diet including macadamia nuts reduced cholesterol as much as a lower-fat diet.
5. Beneficial for Type 2 Diabetes and Metabolic Syndrome
Type 2 diabetes is a common disease affecting hundreds of millions of people worldwide.
Metabolic syndrome refers to a group of risk factors that may increase your risk of heart disease, stroke, and type 2 diabetes.
Therefore, type 2 diabetes and metabolic syndrome are strongly linked.
Interestingly, nuts may be one of the best foods for people with metabolic syndrome and type 2 diabetes.
First off, they’re low in carbs and don’t raise blood sugar levels much. Thus, substituting nuts for higher-carb foods should lead to reduced blood sugar levels.
Studies suggest that eating nuts may also lower oxidative stress, blood pressure, and other health markers in people with diabetes and metabolic syndrome.
In a 12-week controlled study, people with metabolic syndrome who ate just under 1 ounce (25 grams) of pistachios twice per day experienced a 9% decrease in fasting blood sugar, on average.
What’s more, compared to the control group, the pistachio group had greater reductions in blood pressure and C-reactive protein (CRP), a marker of inflammation linked to heart disease.
However, the evidence is mixed and not all studies note a benefit from eating nuts in people with metabolic syndrome.
6. May Reduce Inflammation
Nuts have strong anti-inflammatory properties.
Inflammation is your body’s way of defending itself from injury, bacteria, and other potentially harmful pathogens.
However, chronic, long-term inflammation can cause damage to organs and increase disease risk. Research suggests that eating nuts may reduce inflammation and promote healthy aging.
In a study on the Mediterranean diet, people whose diets were supplemented with nuts experienced a 35% and 90% decrease in the inflammatory markers C-reactive protein (CRP) and interleukin 6 (IL-6), respectively.
Similarly, some nuts — including pistachios, Brazil nuts, walnuts, and almonds — have been found to fight inflammation in healthy people and those with serious conditions like diabetes and kidney disease.
Yet, one study on almond consumption in healthy adults observed little difference between the almond and control groups — though a few inflammatory markers decreased in those eating almonds.
7. High in Beneficial Fiber
Fiber provides many health benefits.
While your body can’t digest fiber, the bacteria that live in your colon can.
Many types of fiber function as prebiotics or food for your healthy gut bacteria.
Your gut bacteria then ferment the fiber and turn it into beneficial short-chain fatty acids (SCFAs).
These SCFAs have powerful benefits, including improving gut health and reducing your risk of diabetes and obesity.
Plus, fiber helps you feel full and reduces the number of calories you absorb from meals. One study suggests that increasing fiber intake from 18 to 36 grams daily may result in up to 130 fewer calories absorbed.
Here are the nuts with the highest fiber content per 1-ounce (28-gram) serving:
8. May Reduce Your Risk of Heart Attack and Stroke
Nuts are extremely good for your heart.
Several studies suggest that nuts help lower heart disease and stroke risk due to their benefits for cholesterol levels, “bad” LDL particle size, artery function, and inflammation.
Studies found that small, dense LDL particles may increase heart disease risk more than larger LDL particles.
Interestingly, one study on the Mediterranean diet found that people who ate nuts had a significant decline in small LDL particles and an increase in large LDL particles, as well as “good” HDL cholesterol levels.
In another study, people with normal or high cholesterol were randomly assigned to consume either olive oil or nuts with a high-fat meal.
People in the nut group had better artery function and lower fasting triglycerides than the olive oil group — regardless of their initial cholesterol levels.
Delicious, Versatile, and Widely Available
Nuts can be enjoyed whole, as nut butters, or chopped up and sprinkled on food.
They’re widely available in grocery stores and online and come in a wide variety of options, including salted, unsalted, seasoned, plain, raw, or roasted.
In general, it’s healthiest to eat nuts raw or toast them in the oven at a temperature below 350°F (175°C). Dry-roasted nuts are the next-best option, but try to avoid nuts roasted in vegetable and seed oils.
Nuts can be kept at room temperature, which makes them ideal for on-the-go snacks and traveling. However, if you’re going to be storing them for long, a refrigerator or freezer will keep them fresher.