Nuts are healthy snack options.

Though they’re usually high in fat, the fat they contain is a healthy type. They're also good sources of fiber and protein.

Many studies have shown that nuts provide various health benefits — especially in regards to reducing heart disease risk factors.

Here are 9 impressive nuts and their health benefits.

In general, nuts are good sources of fat, fiber and protein.

Most of the fat in nuts is monounsaturated fat, as well as omega-6 and omega-3 polyunsaturated fat. However, they do contain some saturated fat.

Nuts also pack a number of vitamins and minerals, including magnesium and vitamin E.

Many studies have investigated the health benefits of increased nut intake.

One meta-analysis of 33 studies found that diets high in nuts do not significantly affect weight gain or weight loss (1).

Yet, despite having little effect on weight, many studies have shown that people who eat nuts live longer than those who don't. This may be due to their ability to help prevent a number of chronic diseases (2, 3, 4, 5).

For example, nuts may reduce risk factors for metabolic syndrome, such as high blood pressure and cholesterol levels (6, 7, 8, 9).

In fact, one study in over 1,200 people found that eating a Mediterranean diet plus 30 grams of nuts per day decreased the prevalence of metabolic syndrome more than a low-fat diet or a Mediterranean diet with olive oil (10).

Furthermore, nuts may reduce your risk of other chronic diseases. For example, eating nuts may improve blood sugar levels and lower your risk of certain cancers (11, 12).

Summary Eating nuts may help reduce risk factors for many chronic diseases, including heart disease and diabetes.

Almonds are tree nuts that contain a number of beneficial nutrients (13).

One serving — 28 grams or a small handful — packs roughly:

  • Calories: 161
  • Fat: 14 grams
  • Protein: 6 grams
  • Carbs: 6 grams
  • Fiber: 3.5 grams
  • Vitamin E: 37% of the Reference Daily Intake (RDI)
  • Magnesium: 19% of the RDI

Almonds may improve cholesterol levels.

A number of small studies have found that eating an almond-rich diet can reduce "bad" LDL cholesterol, total cholesterol and oxidized LDL cholesterol, which is particularly harmful to heart health (14, 15, 16).

However, one larger study combined the results of five other studies and concluded that the evidence is insufficient to suggest that almonds undoubtedly improve cholesterol (17).

Nevertheless, almonds consumed as part of a low-calorie diet may aid weight loss and lower blood pressure in people who are overweight or obese (18, 19).

In addition, eating a meal with one ounce (28 grams) of almonds may help lower the rise in blood sugar that happens after a meal by as much as 30% in people with diabetes but not significantly in healthy people (20).

Moreover, almonds have been shown to reduce inflammation in people with type 2 diabetes (21).

Finally, almonds may have a beneficial effect on your gut microbiota by supporting the growth of beneficial gut bacteria, including Bifidobacteria and Lactobacillus (22).

Summary Almonds contain a number of important nutrients that may help reduce heart disease and diabetes risk factors. However, larger studies are needed to confirm these effects.

Pistachios are a commonly consumed nut that is high in fiber (23).

A one-ounce (28-gram) serving of pistachios contains roughly:

  • Calories: 156
  • Fat: 12.5 grams
  • Protein: 6 grams
  • Carbs: 8 grams
  • Fiber: 3 grams
  • Vitamin E: 3% of the RDI
  • Magnesium: 8% of the RDI

Similarly to almonds, pistachios may improve cholesterol levels — eating 2–3 ounces (56–84 grams) of pistachios a day may help increase "good" HDL cholesterol (24).

Also, pistachios may help improve other heart disease risk factors, including blood pressure, weight and oxidative status.

Oxidative status refers to blood levels of oxidized chemicals, which can contribute to heart disease (25, 26, 27, 28).

What’s more, pistachios may help reduce the rise in blood sugar after a meal (29).

Summary Pistachio nuts appear to have beneficial effects on heart disease risk factors when eaten in high quantities of more than one ounce (28 grams) per day.

Walnuts are a very popular nut and an excellent source of the omega-3 fatty acid alpha-linolenic acid (ALA) (30).

A one-ounce (28-gram) serving of walnuts contains roughly:

  • Calories: 182
  • Fat: 18 grams
  • Protein: 4 grams
  • Carbs: 4 grams
  • Fiber: 2 grams
  • Vitamin E: 1% of the RDI
  • Magnesium: 11% of the RDI

Walnuts appear to improve a number of heart disease risk factors, which may be due to their high content of ALA and other nutrients.

Several large studies have found that eating walnuts significantly reduced total cholesterol and “bad” LDL cholesterol while increasing "good" HDL cholesterol levels (31, 32, 33).

They may also improve other factors related to heart health, including blood pressure and the normal flow of blood through your circulatory system (34, 35).

In addition, walnuts may help reduce inflammation, which can contribute to many chronic diseases (36).

Interestingly, a study in college students found that eating walnuts increased a measure of cognition called "inferential reasoning," suggesting that walnuts may have beneficial effects on the brain (37).

Summary Walnuts are a great source of the omega-3 fat ALA and many other nutrients. Eating walnuts may benefit heart health and potentially even your brain.

Cashews are part of the tree nut family and have a good nutrient profile (38).

One ounce (28 grams) of cashews contains roughly:

  • Calories: 155
  • Fat: 12 grams
  • Protein: 5 grams
  • Carbs: 9 grams
  • Fiber: 1 gram
  • Vitamin E: 1% of the RDI
  • Magnesium: 20% of the RDI

A number of studies have examined whether diets high in cashews can improve symptoms of metabolic syndrome.

One study found that a diet containing 20% of calories from cashews improved blood pressure in people with metabolic syndrome (39).

Another study noticed that cashews increased the antioxidant potential of the diet (40).

Interestingly, a few studies have shown that diets high in cashews may increase blood sugar in people with metabolic syndrome (39, 41).

Another larger study observed that a diet rich in cashews reduced blood pressure and increased levels of “good” HDL cholesterol. However, it had no significant effects on body weight or blood sugar levels (42).

Summary Cashews contain a number of important nutrients and studies indicate that they may improve blood lipid levels and reduce blood pressure.

Pecans are often used in desserts, but they’re quite nutritious on their own (43).

One ounce (28 grams) of pecans contains roughly:

  • Calories: 193
  • Fat: 20 grams
  • Protein: 3 grams
  • Carbs: 4 grams
  • Fiber: 2.5 grams
  • Vitamin E: 2% of the RDI
  • Magnesium: 8% of the RDI

A few studies have shown that pecans can lower “bad” LDL cholesterol in people with normal cholesterol levels (44, 45).

Like other nuts, pecans also contain polyphenols, which are compounds that act as antioxidants.

In one four-week study, people who ate pecans as 20% of their daily calorie intake showed improved antioxidant profiles in their blood (46).

Summary Pecans contain a variety of beneficial nutrients. They also pack antioxidants and may help lower “bad” LDL cholesterol.

Macadamia nuts contain a wide range of nutrients and are a great source of monounsaturated fat (47).

One ounce (28 grams) contains roughly:

  • Calories: 200
  • Fat: 21 grams
  • Protein: 2 grams
  • Carbs: 4 grams
  • Fiber: 2.5 grams
  • Vitamin E: 1% of the RDI
  • Magnesium: 9% of the RDI

Many of the health benefits of macadamia nuts are related to heart health. This may be due to their high content of monounsaturated fat.

A number of studies have shown that diets rich in macadamia nuts can lower both total cholesterol and “bad” LDL cholesterol in those with high cholesterol levels (48).

A macadamia-rich diet even produced effects similar to a heart-healthy diet recommended by the American Heart Association (49).

In addition, macadamia nuts may reduce other risk factors for heart disease, including oxidative stress and inflammation (50).

Summary Macadamia nuts are very high in monounsaturated fat. This may explain their ability to reduce heart disease risk factors.

Brazil nuts originate from a tree in the Amazon and are an incredibly rich source of selenium (51).

A one-ounce (28-gram) serving of Brazil nuts contains about:

  • Calories: 182
  • Fat: 18 grams
  • Protein: 4 grams
  • Carbs: 3 grams
  • Fiber: 2 grams
  • Vitamin E: 8% of the RDI
  • Magnesium: 26% of the RDI

Selenium is a mineral that acts as an antioxidant. Though it’s used for a number of bodily functions, you only need to obtain small amounts of it through your diet.

A one-ounce (28-gram) serving of Brazil nuts will provide you with more than 100% of the RDI for selenium.

Selenium deficiency is rare and usually only occurs in certain disease states.

For example, one study found that people undergoing hemodialysis for kidney disease were selenium deficient.

When these people ate just one Brazil nut a day for three months, their blood selenium levels returned to normal, and the nuts had an antioxidant effect in their blood (52).

Brazil nuts can also reduce cholesterol levels. What’s more, they may reduce oxidative stress and improve the function of blood vessels in obese teenagers (53, 54).

Finally, Brazil nuts may reduce inflammation in both healthy people and those undergoing hemodialysis (55, 56).

Summary Brazil nuts are an excellent source of selenium. They may also help reduce cholesterol levels, oxidative stress and inflammation.

Hazelnuts are very nutritious (57).

One ounce (28 grams) of hazelnuts contains roughly:

  • Calories: 176
  • Fat: 9 grams
  • Protein: 6 grams
  • Carbs: 6 grams
  • Fiber: 3.5 grams
  • Vitamin E: 37% of the RDI
  • Magnesium: 20% of the RDI

Like many other nuts, hazelnuts appear to have beneficial effects on heart disease risk factors.

One study found that a hazelnut-rich diet reduced total cholesterol, “bad” LDL cholesterol and triglycerides. It also lowered markers of inflammation and improved blood vessel function (58).

Other studies have shown that hazelnut diets can improve cholesterol levels and increase the amount of vitamin E in the blood (59, 60).

Summary Hazelnuts are a good source of many nutrients, such as vitamin E. They may also reduce heart disease risk factors.

Unlike the other nuts in this article, peanuts are not tree nuts, but belong to the legume family.

However, they have similar nutrient profiles and health benefits as tree nuts (61).

One ounce (28 grams) of dry-roasted peanuts contains roughly:

  • Calories: 176
  • Fat: 17 grams
  • Protein: 4 grams
  • Carbs: 5 grams
  • Fiber: 3 grams
  • Vitamin E: 21% of the RDI
  • Magnesium: 11% of the RDI

A study in over 120,000 people found that higher peanut intake was associated with lower death rates (2).

Peanuts may also improve heart disease risk factors(62).

Interestingly, one study found that women who ate peanut butter more than five times a week had lower rates of type 2 diabetes (63).

Furthermore, asthma and allergic disease rates may be lower in children of mothers who ate peanuts once or more per week during pregnancy (64).

However, many brands contain large amounts of added oils, sugar and other ingredients. Therefore, it’s best to choose peanut butter with the highest peanut content.

Similarly, peanuts are usually salted, which may eliminate some of their associated health benefits. Instead, try to choose plain, unsalted, unflavored peanuts.

Summary Unlike most other nuts, peanuts belong to the legume family. However, they have nutrient profiles that are similar to tree nuts and may also help reduce risk factors for heart disease and diabetes.

Nuts are one of the healthiest snacks you can eat, as they contain a wide range of essential nutrients.

However, their beneficial effects are attributed to nuts that have been minimally processed and have no added ingredients.

Many processed nut products, such as peanut butter, often contain high amounts of salt or added sugar. As a result, it's best to buy nuts with nothing else added.

When incorporated into a healthy diet consisting of other natural, whole foods, nuts may help reduce risk factors for many chronic diseases.