Derrick W. Spell, MD FACP
Fruit: Can an Apple a Day Really Keep the Doctor Away?
Updated: Feb 12, 2020
I recently saw a new patient who asked a lot of questions about fruit. She had been convinced by her friends that she should not eat fruit, especially since she had breast cancer. I could not believe my ears! After a brief dialogue, I discovered that her main concern with fruit was the sugar content. Given the recent proliferation of “low-carb” fad diets (like the keto diet), I feel compelled to set the record straight about fruit!
In our last blog, we reviewed the harmful effects of sugar. We learned to be careful of “added sugars” and to avoid those products. There is no doubt that excessive sugar intake is harmful. However, one cannot assume that fruit consumption is bad just because of the sugar content. On the contrary, fruit is an integral part of a normal, well-balanced diet!
Fruits are filled with water and both types of fiber. Soluble fiber and insoluble fiber combine like a latticework in the duodenum, or upper small intestine. This network of fiber slows down absorption, so that the sugar in fruit arrives at the liver more slowly and evenly. The fiber content of fruit also allows some of the sugar to move further down the small intestine to the jejunum and ileum. These lower small intestines are home to bunches of bacteria and microorganisms that ingest and metabolize some of the sugar. (In other words, you don’t even absorb all the sugar even though you consume it!)
There are many healthy properties of fruit that warrant further discussion. Fruits are naturally low in fat, sodium and calories. They have no cholesterol. Fruits are rich in essential vitamins and minerals, especially vitamin C, potassium and folic acid. Many fruits also contain phytochemicals, which are natural compounds that have an array of health benefits such as cancer prevention and improved cardiovascular health. Berries and cherries are wonderful sources of phytochemicals. In addition, blueberries are now believed to help prevent Alzheimer’s disease because they are rich in phytochemicals called anthocyanins. (The skin of fruits is typically rich with both fiber and phytochemicals. Berries have more skin, pound for pound, than larger fruits. Therefore, they have more potential health advantages!)
A study published in the March 2019 issue of the Journal of the Academy of Nutrition and Dietetics found that moderate fruit intake was linked with a lower risk of heart disease, diabetes, stroke, and cancer. Other studies confirm that increased fruit intake can lower blood pressure and reduce oxidative stress, the balance between harmful free radicals and protective antioxidants. Fruit can also be quite filling. The fiber in fruit allows the food molecules to reach your ileum sooner. Your gut then signals your brain that you are full. Fruits like apples, pears, and oranges are among the most filling. (This increased satiety may help with weight loss!)
The USDA dietary guidelines recommend two cups or servings of fruit per day for most people. They recommend eating a variety of fresh fruit. They suggest not only eating fruit as a snack, but also incorporating it regularly with meals like breakfast and lunch. You can learn more information at https://www.choosemyplate.gov/eathealthy/fruits/fruits-tips.
I believe the USDA guidelines are appropriate for most Americans. However, I encourage you to add fruit to your daily routine as much as possible. Fruit is a great complement to any meal. It is a convenient snack as well as the healthiest dessert around! Make sure you eat a variety of fruits with different colors. Don’t be afraid to occasionally try a new fruit, especially if it is in season! Visit your local fruit stand or farmer’s market and ask for a recommendation. (After one such suggestion, my wife just tried a persimmon for the first time and loved it!) Fresh fruit is always best, though frozen fruit is acceptable. Canned or dried fruits with added sugars should be avoided. Fruit juices should also be avoided since they lack fiber. Adding fresh or frozen fruit to a healthy smoothie is acceptable. Strive to eat berries each day. Feel free to eat any fresh fruit that you love! Even the recently criticized “tropical” fruits like pineapple have high amounts of fiber and nutrients. If you enjoy grapes, make sure that you do not overindulge. (Grapes are the only fruit that has a poor sugar-to-fiber ratio!)
Truthfully, fruit is the healthiest sweet on Earth. That is why some refer to it as “nature’s fast food!” So yes, an apple (or cup of berries) a day just might keep the doctor away! If you want to learn more about proper nutrition and other valuable food choices, please check out my book The Bite-Sized Guide to Getting Right-Sized!