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Secret Side Effects of Eating Apples, Says Science

If you have to decide between two snacks and one is an apple, your decision is simple.
FACT CHECKED BY Olivia Tarantino

As sure as God made little green apples, America's most abundant fruit is loaded with health-promoting nutrients like antioxidants, vitamins, minerals, fiber, and other good-for-you compounds. It's hard to go wrong when you start your day shining up a Mac, Red Delicious, or Honey Crisp on your sleeve. It's no wonder some clever Welsh bloke from Pembrokeshire had the wisdom to coin the adage that eventually shortened to, "an apple a day keeps the doctor away."

That pearl of wisdom still holds true. In the pantheon of snack foods, the apple reigns supreme as the largest source of antioxidants from fruits consumed in the United States. These plant-based compounds containing phenols can halt the reaction of free radicals with other molecules, preventing damage to your DNA, which in turn may slow aging and protect against chronic disease.

But that doesn't mean there are no negative side effects associated with eating apples. There are, but consider the alternatives before making apples a forbidden fruit. First, take a bite out of these good and not-so-good side effects of eating apples, according to science. And for more Eat More Fruit advice, check out our story about Ways Eating Fruit Can Help You Lose Weight.

Chronic Disease Prevention

apple cinnamon overnight oats

Apples are a rich source of phytochemicals: powerful compounds that studies show have strong antioxidant activity, inhibiting the growth of cancer cells and decreasing the oxidation of blood fats. And epidemiological observations suggest that eating apples may reduce the risk of certain cancers. A review of studies published in Planta Medica found that people who ate one or more apples a day had less risk of multiple types of cancer than people who ate fewer apples.

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Lower Cholesterol and Blood Sugar

almond butter apples

Don't ever peel an apple. Why? Two-thirds of the fiber and most of those free-radical-fighting antioxidants are found in the peel. Apples are a good source of pectin, which is a soluble fiber found in apple peels that can help support heart health by lowering LDL "bad" cholesterol and also improve blood sugar control, reducing your risk of developing type 2 diabetes. By combing with water in the digestive system, pectin forms a gel that slows down digestion and prevents carbohydrates from being quickly absorbed into the bloodstream.

Weight Loss

green apples

"Apples are mostly made up of water and fiber and are relatively low in calories, making them a filling snack and perfect for weight loss," says Lisa R. Young PhD, RDN, author of Finally Full, Finally Slim: 30 Days to Permanent Weight Loss One Portion at a Time.

Try eating a small apple as an appetizer before dinner instead of cheese and crackers or bread—you'll save calories and fill your belly. In a clinical trial published in Nutrition, researchers gave three groups of overweight women one of three foods with which to supplement their meals: apples, pears, or oat cookies, and instructed them to eat their supplement three times a day. At the end of 12 weeks, only the fruit eaters lost weight (an average of 2.7 pounds!).

Regular Bowel Movements

bowl of apples

If you're finding yourself having regular trouble staying regular, start crunching on this natural laxative. The insoluble type of fiber in apples will help prevent constipation by drawing water into your intestines and adding bulk to your stool, making it move through your bowels more quickly. Apples also contain sorbitol and fructose, which also draw water into the intestines and soften the stool.

Read more: The Best Supplements for Digestion, According to Dietitians

A Healthier Microbiome

apple slices cheddar cheese

Eating apples can fertilize a healthier gut. In a study in Frontiers in Microbiology, researchers discovered that the typical apple delivers 100 million bacteria to your gut, 1,755 different kinds, that is if you eat the whole thing, including peel, fruit, stem, and seeds. But even if you skipped the seeds and stems, you'd still get an abundance of different strains of bacteria to grow a diverse garden of microbes, the hallmark of good gut health. A healthy, diverse gut microbiome has been linked to a stronger immune system and reduced risk of diabetes and heart disease.

Soft Teeth & Cavities

apples peanut butter

Apples have been called "nature's toothbrushes." The thinking has been that chewing the fibrous fruit scrubs away food particles and plaque. But while crunching on an apple after dinner will probably dislodge that annoying piece of spinach between your teeth, it doesn't take the place of a good brushing. A 2018 report in Plos One found that eating apples, which are highly acidic, is associated with tooth wear in the enamel and early exposure of the dentine beneath the enamel. Eating apples creates an acidic environment in the mouth, which provokes a lowering of the pH of plaque. Long periods of low pH allow cavity-causing bacteria to flourish, the research showed.

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Jeff Csatari
Jeff Csatari, a contributing writer for Eat This, Not That!, is responsible for editing Galvanized Media books and magazines and for advising journalism students through the Zinczenko New Media Center at Moravian University in Bethlehem, PA. Read more about Jeff
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