What Really Happens To Your Body When You Eat An Apple Every Day

There's nothing quite like biting into a fresh, flavorful apple. The fruit has been revered throughout history for its myriad uses and vast diversity, with thousands of varieties grown throughout the United States and around the world (via University of Illinois). Being one of the most commonly consumed fruits out there has meant that apples have been the subject of extensive scientific research (via Today's Dietitian).

A favorite of the ancient Romans and Greeks, the fruit has been used for centuries to prevent and treat a number of ailments, and is known to impart a broad range of nutritional benefits from quercetin to calcium to vitamin C, per the University of Illinois. There appears to be merit to the old English adage: "An apple a day keeps the doctor away," as studies, such as the one in Advances in Nutrition, show that apples can support your health in numerous ways. In fact, regularly consuming apples has been linked to positive outcomes for various illnesses including diabetes, osteoporosis, dementia, and even cancer.

Like any food or substance, however, it's possible to have too much of a good thing. The healthy fruit is not a cure-all, and can even bring about some unpleasant side effects for some people like gas, bloating, and abdominal pain (via Livestrong.com). Here are some things that happen to your body when you eat an apple every day.

Your risk of heart disease is lowered

One of the main ways that a daily apple can keep you out of the doctor's office is by lowering your risk of cardiovascular disease (via Mayo Clinic). Apples are packed with heart-healthy nutrients such as flavonoids — a group of phytonutrients (plant chemicals) that are lauded for their myriad health benefits including their antioxidant and anti-inflammatory behaviors, according to the Linus Pauling Institute.

A 2020 article published in the journal Scientific Reports revealed that flavanols — a class of flavonoids that are naturally present in apples — are associated with cardiovascular disease prevention, based on the findings that a high intake of flavanol-rich foods lower blood pressure in both men and women.

Another 2020 study published in the American Journal of Clinical Nutrition demonstrated that eating two apples a day can help prevent a heart attack or a stroke. The researchers discovered that participants reaped these benefits only when they consumed two whole apples rather than drinking apple juice (which doesn't quite have the same effect), landing on the conclusion that the compounds in a solid piece of fruit, namely fiber, are what give it these healthy heart-promoting properties. Eating apples regularly is associated with up to a 52% lower stroke risk, says research published by the American Heart Association.

Cholesterol levels are reduced

Eating two apples per day helps reduce your blood cholesterol, reports the 2020 study published in the American Journal of Clinical Nutrition, which might explain the link between apples and a lower risk of heart disease. The researchers attribute this specific health benefit to a soluble fiber called pectin, which is reported to speed up transit time in the colon and reduce constipation.

Moreover, soluble fiber (meaning it can be absorbed in water) helps prevent the buildup of cholesterol in the lining of blood vessel walls by dissolving into a gel-like substance that sticks to cholesterol and eliminates it from your body (via Livestrong.com). This lowers the occurrence of atherosclerosis, explains the University of Illinois, which is where obstruction of blood flow is caused by plaque buildup in the walls of the arteries (via WebMD).

Research published by the American Journal of Clinical Nutrition shows that soluble fiber improves cholesterol by binding to bile acids that are secreted into the small intestine. Approximately 15–20% of the pulp of an apple is said to consist of this cholesterol-busting fiber (via Healthline).

Your digestive system is kept healthy

Being an excellent source of fiber, apples do a great job at helping you to regulate and clean out your digestive system (via Mayo Clinic). Insoluble fiber (which doesn't dissolve in water) promotes the movement of food through the intestines, increasing regularity and stool bulk, and relieving constipation. Soluble fiber, on the other hand, dials down the speed of digestion and helps you feel satiated faster and for longer so that you're not overeating (via Harvard Health Publishing). This explains why people who eat apples on a daily basis tend to experience fewer symptoms of diarrhea and constipation, indicates a 2014 study published in the National Library of Medicine.

The pectin in apples is also considered a prebiotic — another win for your digestive system, according to research reported by Nutrients. It aids the growth of beneficial bacteria (probiotics) in your gut, which help break down food, improve nutrient absorption, and reduce the overgrowth of harmful bacteria in the digestive tract. A 2008 study in BMC Gastroenterology suggests that pectin might also reduce the frequency and severity of acid reflux symptoms, which is when stomach acid flows back into the food pipe causing a painful sensation in the throat and chest.

It's recommended that you eat your apples with their skin on, per the University of Illinois, since this part of the fruit packs one-third of its total fiber content (via Livestrong.com).

Your gut health might improve

Besides assisting with digestion, apples stimulate the growth of healthy bacteria in your gut. A 2019 study published in the journal Frontiers in Microbiology compared the variety of strains of bacteria that reside in organic and nonorganic apples to see how they differ. The researchers uncovered that one apple alone contains 100 million bacteria, and that organic apples are colonized by a more balanced and diverse bacterial community compared to conventional apples, which is linked to better gut health. The pulp and seeds were found to be bacterial hot spots, while Lactobacillus (a friendly bacteria that's frequently used in probiotics) was more prevalent in the skin of organic apples. Hence, you get the best benefits from eating the entire apple — peel, core, and all.

The study brought to light the fact that the diverse microbiota of organic apples can improve your gut health, which has a knock-on effect on your overall physical and mental health (via Eat This, Not That). Specifically, the microbes join and collaborate with the trillions of bacteria already existing in your gut, supporting a range of important functions from digestion to metabolism to your immune system (via The Atlantic). The researchers cite one of the main advantages of organic and unprocessed apples is the potential to lessen food-borne pathogens and allergies, making them a useful tool to manage and prevent allergic diseases.

Some people experience tummy troubles

While apples can provide a plethora of health benefits, overdoing it on the fiber can trigger a number of digestive issues, warns the U.C. Davis Department of Nutrition. Some of the possible side effects of eating too much fiber include bloating, stomach cramps, weight gain, constipation or diarrhea, or an ability to absorb minerals and vitamins properly (via Medical News Today). If you're consuming large amounts of fiber, it's recommended that you drink at least eight glasses of water a day to ensure you're properly hydrated (via U.C. Davis Department of Nutrition).

Due to their slightly acidic pH, apples can also induce gastrointestinal woes like acid reflux (via Healthline). Most people are able to consume red apples without any major issues, whereas those with extra-sensitive tummies may find that the green ones can be a little more aggravating for the upper gastrointestinal tract, so it's important that you listen to your body when it comes to deciding how many to eat.

"Eating too many apples can lead to digestive upset due to the fruit sugar, or fructose, content of this fruit. Fructose is a type of carbohydrate found in fruit and can cause gastrointestinal distress," dietitian Trista Best noted via News Break. Dietician Diana Gariglio-Clelland also added: "Apples are especially high in fructose, a type of sugar found in fruit. Some people have sensitivities to fructose, leading to malabsorption and an increase in gas from bacteria fermenting the sugars in the large intestine."

Some people lose weight

A diet consisting of a daily dose of apples is believed to support healthy weight loss in some people. A 2003 study published in the journal Nutrition found that eating three apples a day helped overweight women to lose weight. The insoluble fiber, namely pectin, in apples is credited for slowing down digestion and helping you feel more satisfied after eating, details the Harvard T.H. Chan School of Public Health.

A 2009 study published in the journal Appetite showed that people who ate apple segments before their meal felt fuller and reduced their subsequent food intake, consuming an average of 200 calories less than those who didn't eat any apple. The results disclosed that a whole apple was more satiating than applesauce or apple juice, and that adding naturally-occurring levels of fiber to the juice didn't increase satiety. This led the researchers to conclude that eating a whole piece of fruit at the start of a meal can be an effective way to manage weight loss. A 2018 review study in the Journal of the American College of Nutrition somewhat corroborated this theory: The researchers established that both regularly eating apples or drinking apple juice over a four to 12 week period aided weight loss in some people.

Your risk of diabetes goes down

The fact that apples are low-glycemic — meaning they're slowly released into the bloodstream as sugar — makes them a good food choice for diabetics, says research published by the medical journal BMJ. Eating a regular supply of apples can help stabilize blood glucose and energy levels, and even halve the risk of diabetes (via Diabetes.co.uk).

A 2011 review in Advanced Nutrition highlighted one study in particular which found that eating an apple a day did a good job of keeping type 2 diabetes away. People who enjoyed a daily apple over a nine-year period had a 28% lower chance of developing the illness compared to those who skipped out on eating the fruit. This was chalked down to the high antioxidant effect of flavonoids, which have been shown to protect cell damage in the pancreas — an organ responsible for secreting insulin when blood sugar levels increase.

Soluble fiber like pectin is deemed another key ingredient in reducing the risk of diabetes, according to researchers for the American Journal of Managed Care. A 2016 study published in the journal Experimental and Therapeutic Medicine reported that regularly consuming soluble fiber helps bring down insulin resistance and improves blood sugar and triglyceride levels in the body.

You could experience blood sugar fluctuations

Apples can certainly be beneficial for some diabetics, but they also have the potential to contribute to blood sugar fluctuations, reports Eat This, Not That! Since apples have a high fructose content, eating a few too many a day could shoot blood glucose levels through the roof, giving rise to a number of related symptoms including headaches, blurred vision, increased thirst or hunger, and frequent urination (via Cleveland Clinic).

"While fruit is a very healthy food, it still contains sugar, which can accumulate from eating too many apples," Diana Gariglio-Clelland, a registered dietician, told News Break, pointing out that: "A medium apple contains around 25 grams of carbohydrates, 19 of which come from sugar."

Due to their high-carbohydrate content, apples may provide a boost in both energy and mood, releasing "feel-good" neurochemicals like serotonin into the body, Josh Axe, a nutrition expert and author, explained via the website Eat This, Not That, adding that consuming too many apples could throw your blood sugar off-balance and precipitate cravings. "For people with poor metabolic health or diabetes, too much sugar from the fruit may also worsen insulin sensitivity or interfere with how well diabetes medications work," Axe warns.

It reduces inflammation in your body

Research shows that an apple a day can help tame inflammation in the body. A 2010 study that appeared in the journal Brain, Behavior, and Immunity identified the soluble fiber in apples as the key to producing a protein called interleukin-4, which has a direct anti-inflammatory impact and strengthens the immune system, making you less susceptible to viruses and infections.

"Soluble fiber changes the personality of immune cells — they go from being pro-inflammatory, angry cells to anti-inflammatory, healing cells that help us recover faster from infection," Gregory Freund, a professor at the University of Illinois College of Medicine, stated via ScienceDaily.

Quercetin, a flavonoid found in apples, is also touted for its anti-carcinogenic and anti-inflammatory capacities, according to a 2019 study in the journal Plant Food, Nutrition and Human Health, which notes that apples are to thank for 4% to 19% of total flavonoids in our diet. Another 2016 study in Nutrients explains that the antioxidant helps the body by decreasing cellular damage and fighting inflammation.

Your immune system is given a boost

The antioxidant and anti-inflammatory powers of apples are believed to play an important role in building up the immune system. Research published in Brain, Behavior and Immunity notes that an apple-rich diet can help transform immune cells from pro-inflammatory ones to anti-inflammatory, giving your overall immune health a sharp boost. A 2018 study published in the journal Immunity lent support to this notion, demonstrating that mice fed with a diet high in fiber were better able to survive the flu. The study went on to hypothesize that the anti-inflammatory properties of short-chain fatty acids in dietary fiber protect against chronic inflammatory diseases and viral infections.

Apples are also well-known for their high vitamin C content, providing around 14% of your daily immune-boosting needs in a single fruit (via Healthline). A 2017 review from the journal Nutrients details the numerous ways that vitamin C can support and bolster immunity, such as by enhancing the epithelial barrier function, which keeps the body well-guarded from pathogens and infections and reduces oxidative stress from environmental factors like pollution or radiation.

Your lips may get itchy

If you've ever found yourself affected by itchy lips after eating an apple, you may have a condition known as oral allergy syndrome (via Verywell Health). This stems from an allergic reaction to a particular kind of pollen that's present in apples — not too different from birch tree pollen. Other common (and slightly annoying) symptoms of oral allergy syndrome include stinging or swelling of the lips and mouth, an itchy tongue or throat, a rash or hives and, more rarely, vomiting, stomach cramps, or diarrhea. But, each individual can react differently.

A daily apple could expose you to a very specific food allergy (via Healthline). The first part of this process is called sensitization, whereby your immune system responds negatively to the food as though registering it as a potential threat. Your body then produces antibodies that interact with the food's proteins, releasing specific substances like histamine, which cause allergic reactions that can range from digestive issues to hives to asthma-like symptoms. If you find yourself battling severe symptoms like breathing difficulties after eating an apple, consult your doctor immediately to avoid a dangerous and potentially life-threatening situation.

Your teeth become healthier and brighter

The slightly acidic makeup of apples means that eating them every day might take its toll on your teeth, gradually wearing away at the enamel, informs a 2016 study published in the journal Dental Health: Current Research. By the same token, the natural juices of apples can help kill harmful bacteria in the mouth and act as a natural whitener for your enamel, keeping your teeth squeaky clean and free of stains, according to a 2018 study published in PLoS One.

The chewing mechanism involved in scoffing down apples, along with their fibrous texture, helps scrub off plaque and tartar, while the saliva that's produced in your mouth washes away residual food pieces, keeping your gums fresh and healthy (via Summit Dental Health). Other important nutrients packed into apples include potassium, which increases bone density, and vitamin C, which protects your gums against harmful bacteria, infections, and bleeding.

Apples even contain a very small amount of fluoride, a mineral that's naturally occurring in various foods (via National Institutes of Health). This helps prevent tooth decay and cavities as well as encouraging new bone growth. Roughly 80% or more of the fluoride that passes into the gastrointestinal tract is orally ingested with a majority of it being stored in the bones and teeth.

It helps you build strong bones

Apples are reported to have a therapeutic impact on your skeletal and bone health. The crisp fruit supports the function of teeth and bone-building minerals like calcium in the body, according to a 2011 review in Advances in Nutrition. A particular study showed that women who included an abundance of apples in their diets experienced significantly less calcium loss than women who didn't eat any apples at all.

Findings from another study that appeared in the Journal of Agricultural and Food Chemistry revealed that eating fresh apples every day can provide access to a unique bone-building flavonoid called phloridzin. This is found exclusively in the fruit, and has been shown to stave off osteoporosis in postmenopausal women when eaten frequently by increasing bone density and reducing inflammation. Another 2005 study in Calcified Tissue International pointed out that a high concentration of phloridzin is located in the peel of the apple while emphasizing that the phytonutrient improves inflammation markers and curbs bone loss.

Asthma symptoms can improve

The pharmacological effects of apples also extend to people with asthma. Chowing down on an apple a day has been shown to work its magic on the respiratory system, notes a 2011 study that appeared in the journal Advances in Nutrition, helping to improve asthmatic symptoms and prevent an asthma attack. Results indicate that women who consumed the highest quantity of apples were at the lowest risk of developing the respiratory disease. Loaded with the antioxidant-rich quercetin, the fruit is believed to reduce oxidative stress in the lungs as well as play an important role in supporting immune health, per research published in the journal Molecules.

A 2017 study of former smokers in the European Respiratory Journal found that, on average, participants who included more than three portions of fresh apples in their diet each day had a slower decline in lung function across a 10-year period compared to those who ate less than one apple a day. The study authors hypothesized that a higher intake of antioxidant nutrients can restore the lung damage caused by prolonged smoking.

It can keep your brain healthy

An apple a day does wonders for your cognitive function, say researchers. In particular, it can enhance brain cells and combat neurodegenerative disorders like dementia, contributing to a healthy brain. A 2021 study in of mice in Stem Cell Reports found that the volume of grey matter in their brains increased after they were injected with flavonoids contained in apples, mimicking the effects of exercise, which has been shown to similarly improve brain function. The study sheds light on the fruit's ability to feed neurons that can heighten learning, memory, and mental performance due to the pro-neurogenic compounds in the peel and flesh.

The healing potential of apples when it comes to the brain is, once again, attributed to flavonoids. A 2020 review published in the journal Biomolecules specifically highlights the anti-Alzheimer's disease properties of quercetin, a flavonoid that protects neurons from oxidative damage and inflammation. Another 2020 study published in The American Journal of Clinical Nutrition lends support to this theory: Results showed that adults aged 50 and older, who consumed large quantities of flavonoid-based foods like apples, were two to four times less likely to develop Alzheimer's disease over a 20-year period, compared to those who had very little of this type of food in their diet.

An apple a day may reduce your mortality rate

Given their extensive nutritional content, it comes as no surprise that apples can go as far as increasing life expectancy. A 2018 study published in EBioMedicine reported that the anti-inflammatory properties of fisetin, another naturally occurring flavonoid in apples, can slow down the aging process. Potent effects were demonstrated on the lifespan of mice, but tests were also carried out on human fat tissue with positive results. What's more, previous research published in Nature Medicine showed that fisetin can help you live longer by eliminating damaged cells in the body.

"These results suggest that we can extend the period of health, termed healthspan, even towards the end of life," Paul D. Robbins, a professor from the University of Minnesota, said to Medical News Today.

In a 2016 review published in the journal Public Health Nutrition, researchers found that apples are able to prevent and lower your risk of various types of cancer, including colorectal, esophageal, oral cavity, and breast cancers, due to their antioxidant properties, which blunt cancer cell growth. Another 2019 study published in The Lancet pinpoints dietary fiber as a key protector against both colorectal and breast cancer as well as diabetes and cardiovascular disease, further reinforcing the medicinal prowess of the popular fruit.