By Dr Joanna McMillan
October 2018

Crunching on an apple, skin and all, could be the healthiest way to eat this super fruit, with new research providing more evidence that the peel has powerful health benefits.

Several studies published in the past year have highlighted the wide-ranging health benefits of apple polyphenols – a large group of natural, plant chemicals that are more concentrated in the apple skin. We were just beginning to discover the potential of these powerful plant chemicals.

Apples are full of nutritional goodness, and apple polyphenols are becoming the stand-out compound that holds the key to many of the fruit’s health benefits. The latest science has found apple polyphenols may have a role to play in weight loss and stopping the growth of cancer cells. Emerging research also shows they may even slow the progression of osteoarthritis.

Like green tea and blueberries, apples are rich in polyphenols. The polyphenols are found in both the white flesh and the skin of apples. However, there are two and a half times as many antioxidants, including polyphenols, in the apple skin.

So crunching on a juicy apple, skin and all, could actually be the healthiest way to eat this super fruit.

I recently reviewed the latest health research on apples. Here’s your summary giving us four new reasons to stop peeling and enjoy snacking on an apple, skin and all:

1. The secret to skin-ny

We’ve known for some time that eating whole apples, as part of a healthy, balanced diet, can help make it easier for you to lose weight by helping you to control your appetite and keep you feeling fuller for longer. (1)

A new review has shed further light on how apples help with weight loss. Published in the Journal of the American College of Nutrition, the review of 13 studies found the high polyphenol levels in apples, especially in the skin, may be directly involved in weight loss and preventing weight gain.(2)

When it comes to keeping the kilos at bay, apple polyphenols play various roles. The researchers found some polyphenols reduced fat and carbohydrate absorption, others helped our bodies breakdown fat to use as fuel, while some fed the gut microbiota helping to create a healthy, balanced and diverse gut microbiota that is needed for better weight control. (2)

As well as polyphenols, the review showed apple fibre fuelled a healthy gut microbiota and the low GI of apples helped to manage blood glucose, insulin control and hunger.(2)

2. Anti-cancer ap-peel

Regularly eating apples is associated with a reduced risk of some of the most common cancers including breast cancer, prostate cancer, colorectal cancer, and non-Hodgkin’s lymphoma.(1)

Building on this, a recent Italian study found apple polyphenols stopped the growth of breast cancer cells in the lab.(3)

The researchers used concentrated extracts from a variety of Italian apples that were particularly high in polyphenols.3 When applied in the lab to human breast cancer cells, the apple polyphenol extract was highly effective in stopping cell growth and killing cancer cells.

This builds on previous evidence showing the same effects with both breast and prostate cancer cells. We can’t yet make the leap to suggest eating apples would have the same effect on the body, but it is exciting research that is beginning to unravel why apples may have an anti-cancer effect. Certainly past studies have highlighted that the consumption of apples is associated with a lower risk of several types of cancer.(4)

3. Help your heart peel good

If an apple a day keeps the doctor away, it could well be because of its ability to help keep your heart healthy. There is a significant body of research that shows regularly eating apples, as part of a healthy balanced diet, can reduce the risk of cardiovascular disease.(1)

A Chinese study recently showed both the polyphenols from the peel and flesh helped to lower blood pressure and cholesterol, improve elasticity of the veins and reduce insulin resistance, when tested on animals. However, the apple peel polyphenols were more effective and researchers are now attributing many heart health benefits to apple polyphenols.(1, 5)

4. Skin and bones

In an emerging area of research, we are just discovering apples may be useful in managing Osteoarthritis – a condition affecting 1 in 5 Australians.(6)

A recent Japanese study has revealed apple polyphenols – specifically the polyphenol procyanidin – helped to maintain healthy cartilage in joints and slowed the progression of osteoarthritis in lab studies and in animals.(7) The next step is to test this in human trials.

Here are three of my favourite ways to enjoy an apple, skin and all:

1. Slice with the skins on and serve with a chunk of cheese – I put this in my kids’ lunch boxes,
2. Slice and smear with nut butter, and
3. Blitz in a blender with spinach, cucumber, celery, mint, a slice of lemon (also with peel on) and a handful of ice cubes to make a delicious green smoothie.

Finally, make sure you store your apples in the fridge when you get home – they’ll stay fresher and keep their crunch for longer.

For more great tips and recipes visit www.aussieapples.com.au

References

1. James-Martin G, Williams G, Stonehouse W. Translating the scientific evidence for apples and pears into health messages. Report for HIA. November 2016.
http://aussieapples.com.au/media/documents/why-are-apples-healthy/The_Apple_Report_2016.pdf
2. Asgary S et al. Weight Loss Associated with Consumption of Apples: A Review. J Am Coll Nut 2018 April https://www.ncbi.nlm.nih.gov/pubmed/29630462
3. D’Angelo, S et al. Pro-oxidant and pro-apoptotic activity of polyphenol extract from Annurca apple and its underlying mechanisms in human breast cancer cells. Int J Oncol. 2017 Sept
https://www.ncbi.nlm.nih.gov/pubmed/28766690
4. Shannon Reagan-Shaw, David Eggert, Hasan Mukhtar & Nihal Ahmad (2010) Antiproliferative Effects of Apple Peel Extract Against Cancer Cells, Nutrition and Cancer, 62:4, 517-524
5. Tain J et al. Comparative study on the effects o apple peel polyphenols and apple flesh polyphenols on cardiovascular risk factors in mice. Clin Exp Hypertens. Nov 2017
https://www.ncbi.nlm.nih.gov/pubmed/29106302
6. https://www.arthritisnsw.org.au/about-arthritis/arthritis-statistics/
7. Masuda I at al. Apple procyanidins promote mitochondrial biogenesis and proteoglycan biosynthesis in chondrocytes. Sci Rep. May 2018 https://www.nature.com/articles/s41598-018-25348-1