Do One Thing in 2018

I was asked recently, "Is there one food you would recommend to be eaten every day?"

My response – “One apple a day.”

Perhaps you have heard this saying, "An apple a day keeps the doctor away."   The original saying is 150 years old and states, "Eat an apple on going to bed and you'll keep the doctor from earning his bread." (1)

This is one of those sayings that has scientific evidence in many areas.

Medications - A 2015 study of apple consumption observed that those who consumed one apple a day required less prescription drugs. (2)  Those who eat one apple a day probably make other healthy choices as well that contribute to this positive association between apples and reduced drugs.

Heart Disease - A 2017 study compared apples high in flavonoids, which are found in the apple skin, with apples low in flavonoids and observed improved blood flow through the brachial arteries when the high flavonoid apples were eaten. (3)  In other words, these apples improved the blood flow through the body.

Cholesterol - The healthy control of cholesterol has also been improved with an apple a day.  A study comparing modern apples with the Annurca apple observed that two small annurca apples a day significantly lowered the bad cholesterol and increased the good cholesterol. (4)  The annurca apple is known for its higher flavonoid content.  Older, heritage apples typically have high flavonoid and polyphenol content.

Blood Sugar – Those individuals who had a daily intake of apple polyphenols, which are from the skin of the apple, had an improved ability to manage blood sugar compared to individuals who did not consume the polyphenols. (5)   One possible reason for this improved sugar control is the polyphenols seem to reduce the sugar absorption ability of the intestines by closing the primary “door” that sugar passes through in the intestines. (6)  

Colon Health – The ability of the polyphenols of apples to “close the door” on sugar transport to cells is one of the pathways to stop the growth of cancer cells in the colon. (7)  A cancer cell has many more “doors” to bring in sugar to accelerate growth, so polyphenols help to close these doors and inhibit the growth of cancer cells.  The peeling of the apple contains the highest content of effective polyphenols with anti-oxidant activity, anti-bacterial activity, and anti-cancer activity. (8)

The older apple varieties that have high polyphenol content include – Braeburn, Jonathan, McIntosh, Gravenstein, and Annurca.  Avoid the newer varieties that have been bred for increased sugar content and size.

An apple a day is one of eight guidelines followed in the Metabolic Balance Program®, a program developed 20 years ago in Germany.  This program provides a personalized meal plan based on your unique blood chemistry.  Those who have followed their personal Metabolic Balance Plan have observed blood sugar levels become controlled, cholesterol levels improve, inflammation decreased, acid reflux disappear, and the body shifts to a healthy weight.

A Free information session about the Metabolic Balance plan is scheduled monthly.  Contact Nutrition Proportion for the next Free Information Session.


1. MacGill, Markus (March 31, 2015) Does an apple a day really keep the doctor away?  Medicinal News Today.

2. Davis M. et al. (2015) Association between Apple Consumption and Physician Visits. Appealing the Conventional Wisdom that an Apple a Day Keeps the Doctor Away. JAMA Intern Med, 75, number 5, published online 30 March 2015, doi:10.1001/jamainternmed.2014.5466.

3. Bondonno NP, et al. (2017) Flavonoid Rich Apple Improves Endothelial Function in Individuals at Risk for Cardiovascular Disease: A Randomized Controlled Clinical Trial. Molecular Nutrition Food Research. 30 October 2017, doi: 10.1002/mnfr.201700674

4. Tenore GC. (2017)  Annurca Apple as a Functional Food for the Contribution to a Healthy Balance of Plasma Cholesterol Levels: Results of a Randomized Clinical Trial. Journal of the Science of Food and Agriculture. 97(7):2107-2115. doi: 10.1002/jsfa.8016

5. Shoji T, et al. (2017) Chronic Administration of Apple Polyphenols Ameliorates Hyperglycemia in High-Normal and Borderline Subjects: a Randomized, Placebo-Controlled Trial. Diabetes Research and Clinical Practice. 129:43-51. 10.1016/j.diabres.2017.03.028

6. Schulze C, et al. (2014) Inhibition of the Intestinal Sodium-Coupled Glucose Transporter 1 (SGLT1) by Extracts and Polyphenols from Apple Reduces Postprandial Blood Glucose Levels in Rats and Humans. Molecular Nutrition and Food Research. 58(9):1795-1808. doi: 10.1002/mnfr.201400016

7. Lin ST, et al. (2016) Apple Polyphenol Phloretin Inhibits Colorectal Cancer Cell Growth via Inhibition of the Type 2 Glucose Transporter and Activation of p53-mediated Signaling. Journal of Agricultural and Food Chemistry. 64(36):6826-6837. doi: 10.1021/acs.jafc.6b02861

8. Luo J, et al. (2016) Antioxidant, Antibacterial, and Antiproliferative Activities of Free and Bound Phenolics from Peel and Flesh of Fuji Apple. Journal of Food Science. 81(7):M1735-42.  doi: 10.1111/1750-3841.13353