FOOD ST★RS – Apples

The apple is somewhat in need of a boost in its public relations.  Apples are likely the most common fruit in many peoples’ kitchens, especially here in northern North America where other more exotic fruits tend to vary seasonally in availability and quality.  They are often found lurking in the back of fridges, gathering wrinkles until some hungry person can’t find anything better to eat and pulls one out for a snack.   Sadly, they are lacking in promoters.  They are not new and exciting and they are not known as a superfood, even though they really are one.  (There is no universally accepted definition of a superfood, but it generally means foods that have wide-ranging health benefits such as disease prevention over and above their simple nutritional value.)

Apples actually have a lot going for them.  They are convenient and portable.  There are multiple types and tastes to choose from.  Their protective outer skin keeps them fresh for long periods of time.  And, as you will soon see, they are bursting with healthy nutrients.

 

What’s inside an apple?

Apples are low in calories, with one cup of chopped apple containing only 65 calories, and they contain no saturated fat or cholesterol. (1)  They are rich in dietary fiber.  They are a good source of Vitamin C.  In fact, one medium apple contains 10% of the recommended Daily Value (DV) of vitamin C, and they are high in other vitamins too as well as in minerals and phytonutrients. (2)

 

One medium 7-ounce (200-gram) apple offers the following nutrients. (2,3)

Note:  DV = recommended daily value in Canada

Calories: 104 kcal

Protein: 0.3 grams

Carbs: 28 grams

Fat:  0.3 grams

Fiber: 5 grams (20% of the DV)

Thiamin (Vitamin B1):  0.22 mg (18% of the DV)

Riboflavin (Vitamin B2):  0.14 mg (11% of the DV)

Niacin (Vitamin B3): 0.18 mg (1% of the DV)

Pyridoxine (Vitamin B6):  0.064 mg (3.8% of the DV)

Folate: 2 mcg

Vitamin C: 9.2 mg (10% of the Daily Value (DV)

Vitamin E: 0.36 mg (2.5% of the DV)

Vitamin K: 4.4 mcg (3.7% of the DV)

Calcium:  14 mg

Copper: 0.068 mg (7.5% of the DV)

Iron:  0.12 mg

Manganese:  0.08 mg (3% of the DV)

Phosphorus:  16 mg

Potassium:  212 mg (6% of the DV)

Zinc:  0.04 mg

Beta-carotene:  119 mcg

 

As you can see, one apple can supply a hefty portion of the nutrients we need every day for optimal health.

Apples also contain natural sugars.  However, whole apples have a low glycemic index of around 36.  Because of their fiber and phytonutrient content, they release their sugars slowly as the whole fruit is digested and do not cause blood sugar spikes after their ingestion. (4)

 

Health Benefits of Apples

Apples house an impressive lineup of phytonutrients.

Quercetin, found mainly in the skin of an apple, is a powerful flavonoid antioxidant that binds to and neutralizes free radicals that can damage cells and DNA. (5)  These anti-inflammatory effects may also reduce insulin resistance, a big risk factor for the onset of diabetes. (6)

Catechins are polyphenol antioxidants that appear to support heart health and to be important in cancer prevention. (7,8)

Chlorogenic acid is a polyphenol antioxidant that has been found in some studies to lower blood sugar and cause weight loss.  It may also play important protective roles for the cardiovascular system, the liver and the central nervous system. (9,10).

Other polyphenol antioxidants present in apples not only add to the protection of cells from the inflammation from free radicals but also exert a myriad of other favourable effects.  Polyphenols are likely responsible for many of the remarkable benefits of eating apples. (11)

Tartaric acid gives apples their “tart” flavour but also acts as an antioxidant to provide protection from harmful pro-inflammatory free radicals. (12)

 

Consumption of apples and pears has been associated with 18% reduction in the risk of Type-2 diabetes.  Just one serving per week of these fruits may reduce the risk by 3% (13).  Recent science delved into a polyphenol in apples called phloridzin which may be playing a part in this risk reduction.  Phloridzin reduces the uptake of sugar from the intestine into the bloodstream.  Trials show that moderate to high intake of phloridzin from apples can improve management of blood glucose levels and reduce the risk of developing type-2 diabetes. (14)

A Dutch prospective study that followed participants for over ten years revealed that higher intakes of white fruits and vegetables (for example, apples and pears) were inversely associated with the incidence of stroke. For each twenty-five gram per day increase in white fruits and vegetables there was a 9% lower risk of stroke. (15)  Other research has shown an association between relatively modest intake of apple and reduced risk of cardiovascular disease and cardiovascular-disease-associated mortality. (16)

A 2016 study examined apple intake and cancer risk and found preliminary evidence that those eating the highest amounts of apples had reduced risk of several cancers including lung, colorectal, breast and digestive tract cancers. (17)  Another analysis illustrated that higher apple intake was associated with lower risk for cancer mortality. (18)  Apple and its phytochemicals indeed show the ability to exert preventative effects on cancer through their antioxidant activity and inhibition of cancer cell proliferation.  However, further research is needed to identify the specific phytochemical(s) responsible for these effects, the amount of apple needed and the timing of apple consumption to achieve these positive effects. (19,24)

Eating apples supports weight control and confers anti-obesity effects through their content of polyphenols which can regulate gene expression and alter signals in cells, especially in fat tissues. (23)  In addition, due to their fiber and water content, apples are filling which helps to manage appetite.  Moreover, ingestion of whole apples slows stomach emptying and causes an increase in the contents of the bowel, thus augmenting the sensation of fullness and satiety. (20)

 

In 2015, a European study took a deep dive into the health effects of apples.  Their findings were surprising. (21)

This research discovered that apples may have the ability to alter the gut microbiota and, in so doing, protect against cardiovascular disease.  A major portion of the bioactive components in apples are not absorbed in the upper gastrointestinal tract but reach the large intestine relatively intact.  Larger polyphenol molecules in particular, along with pectin, the major soluble fiber in apples, and other cell wall components of apples, reach the colon mostly undigested and are extensively metabolized there by the microbiota.  The result is the production of metabolites that effect the intestine locally (improving the gut barrier function and reducing intestinal permeability (leaky gut)) as well as offering farther reaching effects.  Additionally, polyphenols appear to have the ability to modulate the gut microbiota composition, inhibiting some detrimental bacterial populations and stimulating other health-promoting ones.  Apple intake has been associated with beneficial effects on lipid metabolism (reduction in total cholesterol); weight management; vascular function; and inflammation.  This study suggests that these healthful outcomes may be linked to the effects of apples on the gut microbiota.

 

 

Notes on eating apples

Hopefully, all this information encourages you to eat more of this very healthy, inexpensive and readily available fruit.  As you enjoy your apples, here are a couple of other points to keep in mind.

Be sure to eat the whole apple, skin and all.  The healthy polyphenol compounds in apples are not evenly distributed within the fruit.  Despite the small contribution of apple peel to the whole fruit weight of only 6 to 8%, the peel contains a significantly higher content of polyphenols. (21)  In addition, the skin of the apple contains half of its fiber. (22)

Environmental reports tell us that apples are among the produce that are the most heavily contaminated with pesticides.  Always wash apples thoroughly before eating and, if possible, buy organic. (22)

 

SOURCES:

1  https://nutritiondata.self.com/facts/fruits-and-fruit-juices/1809/2

2  https://www.nutrition-and-you.com/apple-fruit.html

3  https://fdc.nal.usda.gov/fdc-app.html#/food-details/1750341/nutrients

4  Hanhineva, K., Törrönen, R., Bondia-Pons, I., Pekkinen, J., Kolehmainen, M., Mykkänen, H., Poutanen, K. Impact of dietary polyphenols on carbohydrate metabolism. Int J Mol Sci. 2010 Mar 31; 11(4):1365-1402. Doi: 10.3390/ijms11041365. PMID: 20480025; PMCID: PMC2871121.

5  Boots, A.W., Haenen, G.R., Bast, A. Health effects of quercetin: from antioxidant to nutraceutical. Eur J Pharmacol. 2008 May 13; 585(2-3): 325-337. Doi: 10.1016/j.ejphar.2008.03.008. Epub 2008 Mar 18. PMID: 18417116.

6  Sato, S., Mukai, Y. Modulation of Chronic Inflammation by Quercetin: The Beneficial Effects on Obesity. J Inflamm Res. 2020 Aug 4; 13:421-431. Doi: 10.2147/JIR.S228361. PMID: 32848440; PMCID: PMC7425105.

7  Bhardwaj, P., Khanna, D. Green tea catechins: defensive role in cardiovascular disorders. Chin J Nat Med. 2013 Jul;11(4): 345-353. Doi: 10.1016/S1875-5364(13)60051-5. PMID: 23845542.

8  Arts, I.C., Jacobs, D.R. Jr, Gross, M., Harnack, L.J., Folsom, A.R. Dietary catechins and cancer incidence among postmenopausal women: the Iowa Women’s Health Study (United States). Cancer Causes Control. 2002 May; 13(4): 373-382. Doi: 10.1023/a:1015290131096. PMID: 12074507.

9  Naveed, M., Hejazi, V., Abbas, M., Kamboh, A.A., Khan, G.J., Shumzaid, M., Ahmad, F., Babazadeh, D., FangFang, X., Modarresi-Ghazani, F., WenHua, L., XiaoHui, Z. Chlorogenic acid (CGA): A pharmacological review and call for further research. Biomed Pharmacother. 2018 Jan; 97: 67-74. Doi:10.1016/j.biopha.2017.10.064. Epub 2017 Nov 6. PMID: 2908046.

10  Thom, E. The effect of chlorogenic acid enriched coffee on glucose absorption in healthy volunteers and its effect on body mass when used long-term in overweight and obese people. J Int Med Res. 2007 Nov-Dec; 35(6):900-908. Doi: 10.1177/147323000703500620. PMID: 18035001.

11  Feng, S., Yi, J., Li, X., Wu, X., Zhao, Y., Ma, Y., Bi, J. Systematic Review of Phenolic Compounds in Apple Fruits: Compositions, Distribution, Absorption, Metabolism, and Processing Stability. J Agric Food Chem. 2021 Jan 13; 69(1):7-27. Doi: 10.1021/acs.jafc.0c05481. Epub 2021 Jan 4. PMID: 33397106.

12  https://www.sciencedirect.com/science/article/pii/B9780128190968000197

13  Guo, X.-F., Yang, B., Tang, J., Jiang, J.-J., Li, D.  Apple and pear consumption and type 2 diabetes mellitus risk: a meta-analysis of prospective cohort studies.  Review Food Funct. 2017 Mar 22; 8(3): 927-934. Doi: 10.1039/c6fo01378c.

14  Niederberger, K.E., Tennant, D.R., Bellion, P. Dietary intake of phloridzin from natural occurrence in foods. Br J Nutr. 2020 Apr 28; 123(8):942-950. dDi: 10.1017/S0007114520000033. Epub 2020 Jan 8. PMID: 31910912.

15  Minich, DmM. A Review of the Science of Colorful, Plant-Based Food and Practical Strategies for “Eating the Rainbow”. J Nutr Metab. 2019 Jun 2; 2019: 2125070. Doi: 10.1155/2019/2125070.

16  Hyson, D.A. A comprehensive review of apples and apple components and their relationship to human health. Adv Nutr. 2011 Sep;2(5):408-420. Doi: 10.3945/an.111.000513. Epub 2011 Sep 6. PMID: 22332082; PMCID: PMC3183591.

17  Fabiani, R., Minelli, L., Rosignoli, P.  Apple intake and cancer risk: a systematic review and meta-analysis of observational studies.  Review Public Health Nutr. 2016 Oct; 19(14): 2603-2617. Doi: 10.1017/S136898001600032X. Epub 2016 Mar 22.

18  Hodgson, J.M., Prince, R.L., Woodman, R.J., Bondonno, C.P., Ivey, K.L., Bondonno, N., Rimm, E.B., Ward, N.C., Croft, K.D., Lewis, J.R. Apple intake is inversely associated with all-cause and disease-specific mortality in elderly women. Br J Nutr. 2016 Mar 14; 115(5): 860-867. Doi: 10.1017/S0007114515005231. Epub 2016 Jan 20. PMID: 26787402.

19  Ribeiro, F.A., Gomes de Moura, C.F., Aguiar, O. Jr, de Oliveira, F., Spadari, R.C., Oliveira, N.R., Oshima, C.T., Ribeiro, D.A. The chemopreventive activity of apple against carcinogenesis: antioxidant activity and cell cycle control.  Eur J Cancer Prev. 2014 Sep; 23(5): 477-480. Doi: 10.1097/CEJ.0000000000000005. PMID: 24366437.

20  Krishnasamy, S.,, Lomer, M.C.E,, Marciani, L., Hoad, C.L., Pritchard, S.E., Paul, J., Gowland, P.A., Spiller, R.C. Processing Apples to Puree or Juice Speeds Gastric Emptying and Reduces Postprandial Intestinal Volumes and Satiety in Healthy Adults. J Nutr. 2020 Nov 19; 150(11):2890-2899. Doi: 10.1093/jn/nxaa191. PMID: 32805050.

21  Koutsos, A., Tuohy, I.M., Lovegrove, J.A.  Apples and Cardiovascular Health – Is the Gut Microbiota a Core Consideration?  Nutrients. 2015 Jun; 7(6): 3959–3998.  Published online 2015 May 26. Doi:10.3390/nu7063959.

22  https://www.healthline.com/nutrition/10-health-benefits-of-apples#TOC_TITLE_HDR_2

23  Asgary, S., Rastqar, A., Keshvari, M. Weight Loss Associated With Consumption of Apples: A Review. J Am Coll Nutr. 2018 Sep-Oct; 37(7): 627-639. Doi: 10.1080/07315724.2018.1447411. Epub 2018 Apr 9. PMID: 29630462.

24  Boyer, J., Liu, R.H. Apple phytochemicals and their health benefits. Nutr J. 2004 May 12; 3:5. Doi: 10.1186/1475-2891-3-5. PMID: 15140261; PMCID: PMC442131.