Apples are one of the most popular fruits — and that's a good thing.

They're an exceptionally healthy fruit with many research-backed benefits.

This article lays out ten of the top health benefits of apples.
1. Apples Are Nutritious

A medium apple is equal to 1.5 cups of fruit.

Two cups of fruit daily are recommended on a 2,000-calorie diet.

Below are some nutrition facts for a medium apple:

    Calories: 95.
    Carbs: 25 grams.
    Fiber: 4 grams.
    Vitamin C: 14% of the RDI.
    Potassium: 6% of the RDI.
    Vitamin K: 5% of the RDI.
    Manganese, copper and vitamins A, E, B1, B2 and B6: Under 4% of the RDI.

Apples are also a rich source of polyphenols. While nutrition labels don't list these plant compounds, they are likely responsible for many of the health benefits.

To get the most out of apples, keep the skin on. It contains half of the fiber content and many of the polyphenols.

    Bottom Line:
    Apples are a good source of fiber and vitamin C. They also contain polyphenols, which can have numerous health benefits.

2. Apples May Be Good for Weight Loss

Apples are high in fiber and water — two qualities that make them filling.

In one study, participants who ate apple slices before a meal felt fuller than those who consumed applesauce, apple juice or no apple products.

In the same study, those who started their meal with apple slices also ate an average of 200 fewer calories than those who didn't (1).

In another study, 50 overweight women added either apples or oat cookies to their diets for 10 weeks. Each item had a similar calorie and fiber content. Those who ate apples lost an average of 2 lbs (1 kg) and ate fewer calories overall (2).

Researchers think that apples are more filling because they are less energy-dense, yet still deliver fiber and volume.

Furthermore, some natural compounds in them may promote weight loss.

A study of obese mice found those given a supplement of ground apples and apple juice concentrate lost more weight and had lower levels of "bad" LDL cholesterol, triglycerides and total cholesterol than the control group (3).

    Bottom Line:
    Apples may aid weight loss in several ways. They're also particularly filling due to their high fiber content.

3. Apples May Be Good for Your Heart

Apples have been linked to a lower risk of heart disease (4).

One reason may be that apples contain soluble fiber, which is the kind that can help lower your blood cholesterol levels.

They also contain polyphenols, which have antioxidant effects. Many of these are concentrated in the peel.

One of these polyphenols is a flavonoid called epicatechin, which may lower blood pressure.

An analysis of studies found that high intakes of flavonoids were linked to a 20% lower risk of stroke (5).

Flavonoids can help prevent heart disease by lowering blood pressure, reducing LDL oxidation and acting as antioxidants (6).

Another study compared the effects of eating an apple a day to taking statins, which are a class of drugs known to lower cholesterol. It estimated that apples would be almost as effective at reducing death from heart disease as statins (7).

However, this was not a controlled trial, so take the findings with a grain of salt.

Another study linked consuming white-fleshed fruits and vegetables, such as apples and pears, to a reduced risk of stroke. For every 25 grams (about 1/5 cup of apple slices) consumed, the risk of stroke decreased by 9% (8).

    Bottom Line:
    Apples promote heart health in several ways. They're high in soluble fiber, which helps lower cholesterol. They also have polyphenols, which are linked to lower blood pressure and stroke risk.

4. They're Linked to a Lower Risk of Diabetes

Several studies have linked eating apples to a lower risk of type 2 diabetes (9).

In one large study, eating an apple a day was linked to a 28% lower risk of type 2 diabetes, compared to not eating any apples. Even eating just a few apples a week had a similarly protective effect (10).

It's possible that the polyphenols in apples help prevent tissue damage to beta cells in the pancreas. Beta cells produce insulin in the body and are often damaged in people with type 2 diabetes.

    Bottom Line:
    Eating apples is linked to a lower risk of type 2 diabetes. This is possibly due to their polyphenol antioxidant content.

5. They May Have Prebiotic Effects and Promote Good Gut Bacteria

Apples contain pectin, a type of fiber that acts as a prebiotic. This means it feeds the good bacteria in your gut.

Your small intestine doesn't absorb fiber during digestion. Instead, it goes to the colon, where it can promote the growth of good bacteria. It also turns into other helpful compounds that circulate back throughout your body (4).

New research suggests this may be the reason for some of the protective effects of apples against obesity, type 2 diabetes and heart disease.

    Bottom Line:
    The type of fiber in apples feeds good bacteria and may be the reason they protect against obesity, heart disease and type 2 diabetes.

6. Substances in Apples May Help Prevent Cancer

Several studies have shown a link between eating apples and a lower risk of cancer.

More specifically, test-tube studies have explored the ways in which the plant compounds in them can combat cancer (10).

One study in women reported that eating apples was linked to lower rates of death from cancer (11).

They may lower cancer risk in several ways, including with antioxidant and anti-inflammatory effects (12).

    Bottom Line:
    Apples have several naturally occurring compounds that may help fight cancer. Observational studies have linked them to a lower risk of cancer and death from cancer.

7. Apples Contain Compounds That Can Help Fight Asthma

Antioxidant-rich apples may help protect your lungs from oxidative damage.

A large study of over 68,000 women found that those who ate the most apples had the lowest risks of asthma. Eating about 15% of a large apple per day was linked to a 10% lower risk of asthma (10).

Apple skin contains a flavonoid called quercetin, which can help regulate the immune system and reduce inflammation. These are two ways in which it affects asthma and allergic reactions (13).

    Bottom Line:
    Apples contain antioxidant and anti-inflammatory compounds that may help regulate immune responses and protect against asthma.

8. Apples May Be Good for Bone Health

Eating fruit is linked to higher bone density, which is a marker of bone health.

Researchers think the antioxidant and anti-inflammatory compounds in fruit help promote bone density and strength.

Some studies show that apples, specifically, may positively affect bone health (14).

In one study, women ate a meal that either included fresh apples, peeled apples, applesauce or no apple products. Those who ate apples lost less calcium from their bodies than the control group (10).

    Bottom Line:
    The antioxidant and anti-inflammatory compounds may promote bone health, and eating fruit can help preserve bone mass as you age.

9. Apples May Protect Against Stomach Injury From NSAIDs

The class of painkillers known as nonsteroidal anti-inflammatory drugs (NSAIDs) can injure the lining of your stomach.

A study in test tubes and rats found that freeze-dried apple extract helped protect stomach cells from injury due to NSAIDs (10).

Chlorogenic acid and catechin are two compounds that were particularly helpful (10).

    Bottom Line:
    Apples contain compounds that may help protect the stomach lining from injury due to NSAID painkillers.

10. The Antioxidants in Apples May Help Protect Your Brain in Old Age

Most research focuses on apple peel and flesh.

However, apple juice may potentially have benefits for age-related mental decline.

In animal studies, juice concentrate reduced harmful reactive oxygen species (ROS) in brain tissue and minimized mental decline (15).

Apple juice may help preserve acetylcholine, a neurotransmitter that can decline with age. Low levels of acetylcholine are linked to Alzheimer's disease (10).

Researchers who fed elderly rats whole apples found that a marker of the rats' memory was restored to the level of younger rats (10).

That being said, whole apples contain all the same compounds as apple juice. It is always a healthier choice to eat your fruit whole.

    Bottom Line:
    According to animal studies, apple juice may help prevent the decline of neurotransmitters that are involved in memory.

11. Anything Else?

Apples are incredibly good for you, and eating them is linked to a lower risk of many major diseases.

For the greatest benefits, eat the whole fruit — both skin and flesh.