An apple a day is supposed to keep the doctor away by reducing the risk of developing cancer, high blood pressure, diabetes, and heart disease.
But it’s time to add to that list, because in addition to being rich in important antioxidant polyphenols, flavonoids, and fiber, it turns out that the non-digestible compounds in apples may help prevent obesity.
Just another health benefit linked to the microbiome and good bacteria in your gut!
This new study by scientists at Washington State University (WSU) was published in the journal Food Chemistry.
For the study, researchers followed two groups of mice: obese mice fed a high-fat diet (45% of calories from fat), and lean mice fed a standard diet (18% of calories from fat).
“What determines the balance of bacteria in our colon is the food we consume.”
Stool samples were taken from all the mice to analyze their gut bacteria, and results showed that the obese mice had a greater imbalance of bacteria compared to the lean mice.
The obese mice were then fed compounds from seven different varieties of apples: Braeburn, Fuji, Gala, Golden Delicious, Granny Smith, McIntosh, and Red Delicious. Their droppings were examined again, and researchers discovered that the bacterial makeup of the stool had changed.
Of the seven different types of apples, the variety with the greatest impact on good gut bacteria was the Granny Smith apple. Its high levels of non-digestible dietary fiber and polyphenols, and low levels of carbohydrates actually changed the proportions of fecal bacteria from obese mice to be similar to that of lean mice – more Firmicutes and fewer Bacteroidetes.
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Researchers explained this was the result of beneficial compounds reaching the colon intact, despite being chewed and moved through stomach acid and digestive enzymes; once in the colon, the compounds ferment, and butyric acid, a byproduct of fermentation, promotes the growth of beneficial gut bacteria.
The findings suggest “a disproportionate amount of unhealthy gut bacteria found in obese individuals may play a role in triggering chronic low grade inflammation in the body. This in turn may cause metabolic disorders such as insulin resistance and high blood sugar levels that lead to more fat being made and stored in the body. When restoring a bacteria balance that mimics the balance seen in lean individuals, the inflammation decreases and less fat is made and deposited in the body.” Translation: by rebalancing your gut bacteria, you may lose weight.
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Ultimately, “what determines the balance of bacteria in our colon is the food we consume,” wrote lead study author Giuliana Noratto, assistant professor at WSU’s School of Food Science.
Eating a Granny Smith as a daily snack not only helps to keep you feeling full in between meals, it also supports a weight loss program by shifting the type of beneficial bacteria in your gut to those that promote a lean physique.
Unfortunately, apples top the “Dirty Dozen,” a list of fruits and vegetables that often have pesticide residues.
Whenever possible, try to buy organic apples to prevent pesticide exposure. If that’s not an option, be sure to wash the skin thoroughly, as that’s where the chemicals are found. You can also try washing with distilled water or a fruit and vegetable wash like Purely Essential or The Honest Company Fruit & Veggie Wash. While peeling the skin may remove most of the pesticide residue, you won’t see the potential benefits because the skin contains much of the fiber and polyphenolic antioxidants you need.
There’s no two ways about it – the best way to enjoy an apple is by eating one fresh. But if you want to make an apple pie as treat, go for it! Just keep the added sugar to a minimum. In fact, here’s our great recipe for Apple Walnut Pie.
We’re in the middle of the autumn apple season, so take advantage of the timing and get that apple a day!
David H. Rahm, M.D. is the founder and medical director of The Wellness Center, a medical clinic located in Long Beach, CA. Dr. Rahm is also president and medical director of VitaMedica. Dr. Rahm is one of a select group of conventional medical doctors who have education and expertise in functional medicine and nutritional science. Over the past 20 years, Dr. Rahm has published articles in the plastic surgery literature and educated physicians about the importance of good peri-operative nutrition.