Central Disricts Branch
APPLE CANCER RESEARCH PROJECT
Information Pack, April 2004
Contents extracted:
INTRODUCTION - MARCH 2004
RESEARCH HIGHLIGHTS - MARCH 2004
- Implications of the research
APPLE CANCER RESEARCH DATA ANALYSIS
POSSIBLE FUTURE RESEARCH DIRECTIONS
RESEARCH UPDATE - MARCH 2004
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INTRODUCTION - MARCH 2004
In November 2002 Central Districts Branch - based on research done overseas into the health giving benefits of apples - formulated the concept of testing heritage apples grown in New Zealand to determine their levels of flavonoids and other beneficial compounds. These compounds are powerful antioxidants that can inhibit the growth of cancer cells and reduce the incidence of heart disease and strokes. They may also be of benefit to people with asthma and diabetes. Our project was based on discovering further understanding about the apple as a medicinal fruit.
In medieval times there was an old English saying "Ate an apfel avore gwain to bed makes the doctor beg his bread", which we all now know as "An apple a day keeps the doctor away". But although we all know this saying, it's as if it's now disconnected from the modern apple of today.
Our hypothesis was that the apple varieties that used to be grown (the heritage varieties) would have far more beneficial compounds in them than modern commercial cultivars. We believe that the results from this project certainly do prove this assumption quite conclusively. This now opens up the possibility, of growing particular varieties specifically for their medicinal fruit.
The New Zealand Government spends billions of dollars on healthcare, for our population each year. This expenditure is growing at an alarming rate, as our general population continues to substitute fresh fruit and vegetables, for processed, preserved, refined and artificial food substitutes. Our bodies are a complex natural system designed to absorb natural products into our metabolism. This degradation of our food system must impact upon people's health. The information gained in this project, highlights the huge potential benefits of eating fresh heritage apples with their inherent medicinal qualities and nutritional benefits.
Many cancers are genetic in their origin. This means that there can be an hereditary predisposition within families, that can lead to the onset of cancer. Growing a medicinal heritage apple tree, where the apples are proven to be high in compounds that reduce the incidence of cancer, may well be an effective way of maintaining wellbeing within the family. Cancer is a complex disease. We intend to have our top two heritage apple varieties tested with the latest available tests, to further test their efficacy against cancer cell. Even once that link of efficacy is established, we cannot give the assurance that these varieties will help everyone. But we are certain that they can be of help to many.
Our sincere thanks to Dr Gordon Lees of the Auckland Branch of the New Zealand Tree Crops Association for his invaluable assistance with this project.
Mark Christensen
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RESEARCH HIGHLIGHTS - MARCH 2004
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Perhaps the most important conclusion is that future breeding programmes for new varieties of food plants should include as a selection criteria, the levels of health-promoting beneficial compounds in the varieties used as parents.
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Verification of the research hypothesis: "That some heritage apple varieties contain considerably more beneficial compounds, such as flavanoids, than modern commercial cultivars, and are therefore substantially better for you". Justifying the age old adage that an apple a day keeps the doctor away (as long as it's a heritage apple).
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Identification of two significant varieties, that have tested consistently high in almost all categories - Hetlina and Monty's Surprise.
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Identification of major flaw in world apple breeding programmes. Current apple breeding programmes ignore the presence of beneficial compounds, resulting in some cases in reductions in their levels. This may have had health implications for our society over at least the last 50 years. Future breeding programmes should include the heritage varieties with the highest flavanoid levels in the selection procedure - which may also increase their flavour.
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Identification of Russet apples as being of potential benefit to people with diabetes. (Further research required).
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Vindication to the many growers of heritage and obscure apple varieties who believe that they are a treasure, needing to be preserved. This research has uncovered simply what people have known and been saying for years - that modern apples do not have the flavour like the old varieties used to. Now we can see why.
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Significant evidence that beneficial compounds can be found in the skin of heritage apples (as well as in the flesh). Approximately 50% of the beneficial compounds can be found in the skin. This highlights the importance of eating the skin. (Note: It is important to wash commercially grown apples, or alternatively eat organic apples).
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Previous research on Red Delicious apples has highlighted how significant the flavanoids and other compounds present in the apples may be on reducing the incidence of cancer, heart disease and stroke. With this report we have identified varieties that have considerably higher levels of the beneficial compounds that influence these diseases. Hence these particular varieties could be grown for their medicinal qualities.
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What are the implications of the research?
Luther Burbank died in 1926. He was the pioneer of modern apple breeding techniques. Breeders choose apples with the qualities that they wish to combine, and our modern commercial cultivars are the result of many years of work with intensive apple breeding programmes. But what have we ended up with? Varieties that are bred for their consumer appeal and handing and storage requirements. None of these apples have been bred to enhance their nutritional or health giving properties.
This research will come as a shock to commercial apple breeders when they compare the levels of compounds in traditional (heritage) apples with those of the modern cultivars, and realise just how much is missing from the modern apple.
It would appear that one unforeseen result of these many years of interbreeding apples has been to average down the levels of compounds in these varieties. So that today when comparing a chemical analysis of Red Delicious (which is generally considered one of the top scoring apples of the 'modern' era in levels of flavonoids etc) to some of the heritage apples you can see that a 'real' apple is full of antioxidants and has the potential to be a powerful pharmacological product - without the side-effects.
What becomes apparent when one compares the data relating to the composition of Red Delicious (a once popular commercial cultivator) with todays modern equivalent - Pacific Rose - is the quantifiable loss of beneficial compounds within that relatively short timespan is hugely significant. Only one compound - chlorogenic acid - is found in significantly higher amounts in the Pacific Rose than in the Red Delicious apple. Unfortunately this is just in the skin, and the skin may well be removed from a commercially grown (i.e. non-organic) apple before being eaten, due to the chemical residues. Hence any potential benefit of this compound would be lost.
Up to now researchers who have chemically analysed apples, thought that these very high levels of compounds, found in these heritage apples, were only present in unpalatable crab apples. There was no commercial rationale for them to test obscure heritage varieties, because hardly anyone was growing them. This can change of course. There is a gradual growing awareness of man's basic requirement for better nutrition because of its impact upon health. Once consumers begin to understand that no two apples are the same; that particular varieties are packed with compounds that may inhibit the growth of cancer cells, may reduce the incidence of heart disease and strokes, then many should choose to eat these apples.
So an opportunity may exist for growers to tap into this health conscious market by growing particular high scoring heritage varieties. To this end, Central Districts Branch is trialling Monty's Surprise, as a future commercial 'pharmacological' apple variety.
Another interesting find with the research relates to the compound called Phloridzin and the related compound Phloridzin-xyloside. These are believed to modulate sugar transport in the intestine and can slow the absorption of sugar. Three of our Russet type apples scored very highly with levels of these compounds. Given that apples are the only major known dietary source of these compounds, these varieties may be significant in the control of diabetes.
Hetlina (Hetliner)
The origins of Hetlina are somewhat confused. It has been attributed with originating in Belgium in 1854, with being a very old German variety and with coming from Czechoslovakia. It was marketed for a number of years by Dieter Proebst of Treedimensions. In his catalogue he described it as "second early season, medium sized, attractively coloured, flesh crisp, very firm, dessert apple, reliable cropper, good disease resistance". Dieter probably sourced his Hetlina from Bob Crowder's collection at Lincoln University.
Monty's Surprise
This is a chance find. A very old tree, probably a seedling. Apples tend to vary in size and can weigh as much as 400 grams. A crisp, good eating apple and an excellent cooking apple. Ready in April. An exciting find.
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APPLE CANCER RESEARCH DATA ANALYSIS
Central Districts Branch, NZ Tree Crops Association
Relevance of specific apple polyphenolics and health:
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*Chlorogenic acid is the major cinnamic acid found in apple and can reach very high concentrations.
Chlorogenic acid has antioxidant activity and recent studies have shown that it is absorbed into the body.
Apples high in chlorogenic acid
Flesh
Skin
Hetlina
1115.7
117.3
Fairbelle
783.00
56.5
Montys Surprise
614.5
86.3
Egremont Russet
391.2
73.8
Comparison with
Red Delicious
178.7
3.3
Pacific Rose
306.7
29.2
Apple flavonoids are found almost entirely in the skin and are composed of glycosides of quercetin.
Quercetin glycosides are powerful antioxidants but have other biological properties such as anti-cancer activity that may be beneficial. In several populations apple is the major source of quercetin after onion. Apple is a good dietary source of quercetin.
Apples high in specific quercetin glycosides and total flavonoids
Skin
Q-rut
Q-gal
Q-glu
Q-xyl
Q-arapy
Q-araf
Q-rham
Hetlina
3.3
105.8
22.7
60.9
81.0
8.7
38.6
Montys Surprise
7.8
135.0
33.0
49.4
115.1
12.0
36.3
Taumarunui Seedling
0.3
155.7
27.2
36.6
75.3
5.1
35.2
Woolbrook Pippin
3.5
138.9
37.1
32.4
53.3
3.5
18.3
Comparison with Red Delicious
3.9
40.2
5.1
14.2
28.4
3.5
8.6
Pacific Rose
5.6
51.4
7.6
13.1
22.4
2.9
8.9
Total Flavonoids
Flesh
Skin
Hetlina
37.7
332.1
Montys Surprise
20.9
398.8
Cortland
19.8
159.0
Taumarunui Seedling
9.1
342.5
Woolbrook Pippin
8.7
294.8
Comparison with Red Delicious
4.5
108.9
Pacific Rose
4.1
111.2
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The flavan-3-ols of apple are catechin, epicatechin and the dimers B2, and B5 (not measured).
These compounds are also found in tea and red wine and are associated with the health benefits of these compounds. Catechin and epicatechin are readily absorbed into the body
Catechin
Epicatechin
B2
Flesh Skin Flesh Skin Flesh Skin Montys Surprise
199.3
30.5
344.6
127.4
379.1
136.8
Hetlina 45.5 12.7 214.2 95.5 210.4 102.0 Holly
43.1
10.0
283.1
83.7
196.6
51.0
Fairbelle 42.4 6.9 264.6 74.0 284.2 69.6 Comparison with Red Delicious
31.0
3.9
132.2
72.6
108.3
67.8
Pacific Rose
14.4
3.4
82.9
39.1
59.9
28.6
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Proanthocyanins are polymers composed of chains of flavan-3-ol units linked together. The number of possible compounds possible is very great due to differences in chain length, the type of interconnecting bonds, and the order of the flavan-3-ol units. Consequently, when analysed by most chromatographic techniques they appear as a prominent 'hump' that can represent many hundreds of different compounds of similar chemical properties. In apple, proanthocyanins are usually composed of epicatechin of various configurations resulting in a large number of compounds with different combinations. There are no standards of proanthocyanins available, so these compounds were quantified as epicatechin equivalents.
Although there is little evidence that proanthocyanins are absorbed into the body there is direct evidence to support their use for enhancing health. Proanthocyanins are effective antioxidants and have other activities such as inhibition of platelet activity. Several successful antioxidant products are based on proanthocyanins including grape seed extract and pine bark extract (Enzogenol and Pycnogenol). Some other fruits also contain substantial proanthocyanin concentrations such as grape, and persimmon. Additionally, the health properties of cocoa (and chocolate) are promoted due to the high proanthocyanin content.
Total Proanthocyanins
Flesh
Skin
Montys Surprise
1426.5
722.0
Laxtons Triumph
1242.4
290.6
Hetlina
1182.1
585.0
I dago Id
1181.4
205.6
Democrat
1110.0
544.6
Fairbelle
1077.6
311.9
Comparison with Red Delicious
546.7
452.5
Pacific Rose
323.5
233.7
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Phloridzin are a type of flavonoid known as dihydrochalcones. Apple is the only major known dietary source of these compounds. Although phloridzin, and the related compound phloridzin-xyloside have antioxidant activity they are also believed to modulate sugar transport in the intestine and can slow the absorption of sugar. This may have particular relevance to diabetics and those wanting to control sugar absorption.
Phloridzin-xyl
phloridzin
Flesh
Skin
Flesh
Skin
Egremont Russet
44.6
22.6
31.6
71.0
Merton Russet
38.7
19.7
14.0
43.3
Takapuna Russet
38.6
19.6
41.6
117.1
Hetlina
33.4
5.1
49.7
12.3
Montys Surprise
20.7
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32.9
14.9
Comparison with Red Delicious 6.6
6.6
37.6
33.3
Pacific Rose
10.3
4.8
6.6
5.6
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The major anthocyanin found in apple is cyanidin 3-0-galactoside (Cy-gal) and is responsible for the red colour of the skin. Cy-gal is usually only found in the skin. Although anthocyanins are antioxidant-active compounds and are believed to be responsible for a large part of the health enhancing attributes of berryfruit, however, compared with berryfruit, concentrations in apple are relatively low.
Cy-gal
Liberty
51.6
Gloster
50.4
Red Jonathan
33.1
Hetlina
23.4
Montys Surprise
3.1
Comparison with Red Delicious 16.0
Pacific Rose
16.2
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The term 'Phenolics' refers to a chemical classification and includes many thousands of known compounds. This class called 'phenolics' is further divided into subclasses. Of particular relevance to apples are the subclasses of 'flavonoids' and 'phenolic acids'.
Total Phenolics
Flesh
Skin
Hetlina
4154.0
1475.0
Montys Surprise
3773.0
1676.0
Fairbelle 3364.8 843.0 Cambridge Pippin
2526.0
966.9
Gewurzluiken 2525.6 582.8 Democrat
1659.2
1042.6
Comparison with
Red Delicious 1293.6
872.4
Pacific Rose
1157.6
543.5
* Descriptions of compounds in apples taken from the Hort Research Report to the New Zealand Tree Crops Association, "Polyphenolic Content of New Zealand grown Heritage Apple" February 2004.
(Back to ANALYSIS)
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POSSIBLE FUTURE RESEARCH DIRECTIONS
Apple breeding programmes that include the levels of beneficial compounds in the selection procedures.
Determination of the effects of climatic conditions, soil and cultivation, and time of harvest on the levels of beneficial compounds in apples. Effect of storage and storage conditions on the levels of beneficial compounds (the British often store apples for a period of months at room temperature as they believe this enhances the flavour). Influence of high pest levels on the beneficial compounds (do any of them serve as fungicides or insecticides?).
Relationships between levels of various phenolics and flavour (which, if any, of the compounds are responsible for bitter, tangy or other flavours associated with apples?).
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RESEARCH UPDATE - MARCH 2004
Professor Rui Hai Liu M.D., Ph.D. from Cornell University's Department of Food Science has agreed to test several of our top heritage apple varieties as identified by our Apple Cancer Research project, for their anti-cancer activity.
Recently Cornell researchers have developed several more advanced anti-cancer assays, and our apples will be tested using these new models.
To this end a carton of Monty's Surprise and Hetlina apples have been sent for analysis, together with Pacific Rose, as a comparison.
We have approached Rachel Page, a scientist from Massey University, as a research partner to further evaluate the significance of high levels of Phloridzin compounds in Russet apples, for the treatment of diabetes.