Research Pathway

This research has looked to find the best open-pollinated tomato varieties in the world for human health, particularly those highest in lycopene for cancer prevention.

Following the world-wide search for heritage tomato varieties conducted by the HFCRT, New Zealanders now have the opportunity to grow what we consider to be ‘real’ tomatoes that contain a more bioavailable form of lycopene. The Trust makes seeds of these varieties freely available as a wellbeing initiative for all New Zealanders.

A search for the best tomatoes for health has uncovered rare heritage varieties that contain a different form of lycopene that is easily absorbed when eaten raw.

Up to now it was generally understood that you needed to cook your tomatoes in order to improve the absorption of lycopene, the powerful antioxidant that appears to exert positive effects upon human health. But the latest New Zealand research shows that the need to cook your tomatoes only relates to modern varieties and may be due to a fundamental flaw in breeding the first red tomatoes.

Eight years of research by the Whanganui based Heritage Food Crops Research Trust (HFCRT) culminated in a human trial at Plant & Food Research in Palmerston North to test the lycopene absorption of a golden/orange heritage tomato called ‘Moonglow’ in comparison with a red heritage variety called ‘Rosalita’. Click here for more details of the human trial – The bioavailability of tetra-cis-lycopene in humans

Trial participants were fed one variety of diced raw tomatoes in a simple meal, and then blood samples were taken at 4, 7 and 24 hours to determine how much lycopene had passed through their intestinal walls and was circulating in their blood. This was followed by a 2 week break before the second tomato variety was eaten and further blood tests were taken.

As expected only small amounts of lycopene from the red tomato variety was detected, however the big surprise was the significant amount of lycopene present from the golden/orange variety, especially after 24 hours – when the amount of lycopene was at its highest.

“It is amazing to realise that 24 hours after eating these raw golden/orange tomatoes they are still providing significant health benefits,” said Mark Christensen, research director for the HFCRT. “We have a wonderful opportunity to improve health outcomes for people by eating the right foods, and these particular golden/orange varieties are far superior in that regard compared to tomatoes of other colours (including red).”

A subsequent pilot trial was undertaken to try and determine just how long tetra-cis-lycopene stays circulating in the blood. The results are shown in the graph above. The golden/orange tomato ‘Olga’s Round Golden Chicken Egg’ was fed to two trial participants and blood samples taken over 48 hours. The results confirmed that tetra-cis-lycopene from eating these raw tomatoes stayed in the blood at high levels for at least two days after consumption.

In 2019 HFCRT funded an Auckland University study whose findings indicated that the tangerine [orange] varieties possess greater potential to be used in conjunction for the treatment and for the prevention of cancer and inflammatory-related diseases.

Pictured right: Hartono Tanambell from Auckland University with a selection of golden/orange tomatoes grown by HFCRT.

Here are Hartono’s papers; “Screening of In Vitro health benefits of Tangerine Tomatoes”

Tangerine tomatoes: origin, biochemistry, potential health benefits and future prospects

Further research is now being carried out at Massey University in Palmerston North using the HFCRT’s ‘Moonglow’ tomatoes and looking at the prevention of osteoporosis. A first review paper from that study states “there is a clear positive association between lycopene intake and reduced bone loss in humans” and further indicates that the form of lycopene in the orange tomatoes grown by HFCRT is estimated to be 8.5 times more bioavailable than the lycopene found in red tomatoes.

Pictured left: Umani Walallawita from Massey University with ‘Moonglow’ tomatoes..

Here is Umani’s paper “Potential Role of Lycopene in the Prevention of Postmenopausal Bone Loss: Evidence from Molecular to Clinical Studies”

The underlying reasons for this significant difference between the lycopene in these golden/orange tomatoes and red tomatoes appear to relate to the chemistry and history of tomato.

The original tomatoes that were introduced into Europe in the 1520’s had been found being cultivated in Mexico. Italians named those original tomatoes  ‘Pomodoro’, which means ‘golden apple’. The HFCRT believes that those original golden tomatoes contained the easily absorbable tetra-cis-lycopene, which has a bent molecular structure and is easily absorbed by the human body when consumed as a raw food – in a salad or picked and eaten straight from the vine. It is believed that ‘Moonglow’ and ‘Olga’s Round Golden Chicken Egg’ tomatoes and other golden/orange varieties that have been chemically analysed and shown to contain tetra-cis-lycopene are strains from those original golden fruit.

Unfortunately when the first Europeans crossed tomatoes to introduce the red colour to improve their consumer appeal, they were not aware that the beneficial easily absorbed form of lycopene was a recessive gene and would be replaced by the dominant red form of lycopene called all-trans-lycopene. This is the form of lycopene in our modern red tomatoes and has a linear molecular structure that cannot pass easily into the bloodstream unless subjected to intense heat.

“We would like to think that if this had been known over 450 years ago they may have considered the red tomatoes inappropriate for human consumption and stuck with the golden ones, or at least changed their name to reflect the significant difference that occurred through the breeding process.”

It is generally known that raw food is better for us, so it has always been an anomaly to be told that tomatoes should be cooked in order to improve the health benefits from their lycopene content. Now with this research we are able to get a better understanding of the detrimental effects that commercial breeding can have in changing the inherent health benefits of the original golden tomatoes. Given that commercial breeding practices have changed little over the 450 years since this mistake was made with tomato, this should be a red flag to all those who undertake this practice and even more importantly a clarion call to all those around the world who save old seed varieties. Without those dedicated individuals and small (mainly non-profit) organisations that have recognized the inherent value of this diverse gene pool of material, we would not now have the varieties to find and return to. If we are to learn from Hippocrates, the father of modern medicine, who said “let food be your medicine and medicine be your food”, then we and our future generations will need these seeds to keep us well.

2024 Research

During the 2024 summer we continued to identify new selections. Two selections of our ‘Spirited’ tomato had the highest levels of tetra-cis-lycopene.

Spirited (colour coded -Blue)

Spirited (colour coded -Yellow)

Other selections with very high levels (of TCL) were Oley; Olga’s Round Golden Chicken Egg; Moonbeam; Tangella; and Carol.

Oley (colour coded -yellow)

One of our Wally’s Spanish plants had evolved to exhibit potato leaves. This we found to be an exciting development as we hypothesize that the original Mexican tomatoes could have had the simple leaf form, described as ‘potato leaf’, as opposed to the regular leaf (where leaf margins are dentate (toothed) or crenate (scalloped), more or less deeply divided or cut (dissected).¹

The regular leaf tomatoes could have originated with the red tomatoes from Peru.

Wally’s Spanish fruit

Wally’s Spanish potato leaf

1 Amy Goldman, “The Heirloom Tomato From Garden to Table”

2023 – Research Notes

High Tetra-Cis-Lycopene Development

In 2023 we did not test all of the varieties we were growing, but just tested 25 individual plants that we felt may have evolved to some degree, from their parent.

Of the 25 tomatoes tested: those ones high in Tetra-cis-lycopene (that have also previously shown to have good lycopene levels) are:

• ‘Moonglow V.3’ had the highest level of tetra-cis-lycopene (at 4.5).
• ‘Olga’s Round Golden Chicken Egg V.2’ had the 3^rd highest tetra-cis-lycopene at 4.2.
• ‘Mini Orange V.2’ tested with 3.3 tetra-cis-lycopene
• This year we had 4 varieties that previously had been high in Beta-carotene, but which have switched to now be high in tetra-cis-lycopene. * These varieties were:
• ‘Optical S1’ (Renamed ‘Gleam’) –2nd highest Tetra-cis-lycopene (at 4.3); good levels of TCL intermediate compounds; highest level of naringenin Chalcone; high in other polyphenolics; 9th highest in Folate.

• ‘Optical (end of row) V.5’ (Renamed ‘Galaxy’) – high in Tetra-cis-lycopene (at 3.5); 3rd highest Folate.

• ‘Best Optical M V.2’ (Renamed ‘Glimpse’) – 3.1 tetra-cis-lycopene; very high intermediate compounds; 10th highest Folate.

• ‘Oracle 2 SBO V.2’ (Renamed ‘Carol’) – 3.8 tetra-cis-lycopene; 5th highest Folate.

• ‘Spirited’ 3.3 tetra-cis-lycopene; high in intermediate compounds; 8th in Folate; high in two polyphenolic compounds.

Spirited Tomato

Other orange tomato varieties that have tested with high levels of tetra-cis-lycopene in either the 2021 or 2022 years that we will continue to grow are: ‘Oley’; ‘Golden Bell’; ‘Moonbeam’; ‘Wally’s Spanish’; ‘Amish Orange Oxheart’; ‘Golden Grape’ and ‘Tangella’.

High Beta-carotene development

In 2015 a tomato plant grew in Mark’s kitchen drain. It was a very small orange tomato that in 2017 testing showed it had 15.3 mg/100g FW (fresh weight) of beta-carotene. This was comparable to tomatoes that had been bred specifically to be high in beta-carotene. We named this tomato ‘Golden Eye’.

Since then, we have made a number of selections, as this tomato evolves. Two of the 2023 selections are:

• ‘Eye drop V.2’ –  2^nd highest Beta-carotene; highest Folate; very good levels of polyphenolics

• ‘Optical (end of row) V.4’ – highest Beta-carotene; 2^nd highest Folate; very high levels of some polyphenolics

*It is interesting how varieties high in Beta-carotene can switch to being high in tetra-cis-lycopene instead. And how the compound mixes and levels change as a result. We see here the possibility that the switch we are seeing is the plant beginning to return to its original form. We actively try and create the best environment, conditions and intent for that to occur.

Our hypothesis is that the original cultivated tomatoes in Mexico were all golden/orange in colour and that they received this colour from tetra-cis-lycopene. Then with the finding by Europeans of wild red currant-sized tomatoes in Peru, someone in Europe crossed those with the larger golden tomatoes and developed the modern red form of tomato. Because the biosynthesis pathway for tomatoes starts at tetra-cis-lycopene, then can develop to the red all-trans-lycopene, and then if it continues, it can become beta-carotene. We assume that if the original Mexican tomatoes developed without any contact with red tomatoes, that there was never the opportunity for them to develop further to beta-carotene, until the intervention of European cross-breeding. Therefore is the evidence we are seeing of high beta-carotene varieties switching back to being high in tetra-cis-lycopene, examples of these plants beginning the process to return to their original form? We will continue our observations and research.

2022 – Research Notes

We sent away 12 selections for analysis. Amongst this group our ‘Moonbeam’ (daughter of ‘Moonglow’) tested with the highest level of tetra-cis-lycopene.

Moonbeam tomato

The ‘Amish Yellowish Orange Oxheart 2’ selection was second highest. (We have renamed this selection ‘Amish Orange Oxheart 2’ for planting in 2023). This Amish tomato is a very old one and prone to variability in the shape of the fruit. It’s flower has a protruding stigma (also called exserted) which sticks out past the flower cone, because of the length of the flower style. This enables cross pollination by bumble bees and insects. Whereas almost all modern tomato flowers have an inserted stigma, enclosed within the flower cone, that cannot be reached by insects to be pollinated, therefore relying upon the flower to pollinate itself.

Amish Orange Oxheart flowers showing protruding stigma (also called exserted).

Example of more common stigma, enclosed within the flower cone, commonly found with modern tomato varieties.

A new selection this year was ‘Oley’ – a selection from ‘Wally’s Spanish’ with smaller medium-sized fruit that had impressed us with the quality of the tomato.

Interestingly this year two of our ‘Oracle’ selections that previously had good levels of beta-carotene, tested with no beta-carotene and instead had good levels of tetra-cis-lycopene.

2021 – Research Overview and Findings

Humans are a part of nature, living in a symbiotic relationship with the plant kingdom. Plants have provided optimum benefits for the nourishment and health of not only humans, but all life forms that feed upon them.

That is until humans interfere (whether deliberately or unintentionally) with the precise makeup of medicinal compounds within plants – tomato being a prime example. Tomato is one of the most deliberately hybridised foods in existence. Starting with changing the cultivated orange tomatoes found in Mexico (that when introduced into Italy in the 1520’s were named ‘Pomodoro’, or ‘Poma Aurea’ in Latin, both meaning ‘Golden Apple’). When those tomatoes were crossed with a tiny wild red tomato, the bioavailable form of lycopene was inadvertently bred out as well as other vital intermediate compounds essential for fulfilling the prime purpose of this species – that of sustenance and medicine for humans.

We recognise our role at HFCRT is to begin the process of helping to return this amazing fruit back to its original form and quality. We allow the plants to naturally evolve. Our role is as conscious participants, without in anyway trying to control the process. Hence we avoid the use of any modern breeding practices. We still have a process that we use, (see end of section), and are excited to see that our 2021 results confirm through the changes that we can see occurring within the fruit, that progress is being made.

The ‘Moonbeam’ Tomato

We have grown the beautiful and tasty ‘Moonglow’ tomato for many years. In 2013 it tested with the highest level of tetra-cis-lycopene amongst our 160 samples for that year. In our 2020/21 year we had a bed of 10 ‘Moonglow’ tomato plants and one plant produced tomatoes that were about one third of the normal size of ‘Moonglow’. We named that plant ‘Moonbeam’ and in the 2021 data these ‘Moonbeam’ tomatoes showed the highest level of tetra-cis-lycopene, and 35% more than ‘Moonglow’. ‘Moonbeam’ tomatoes have a lovely mild flavour.

The figure below shows UHPLC contour chromatograms for the ‘Moonbeam’ tomato. The unknown compound may be a neurosporene isomer but is yet to be verified. The carotenoid with retention time of 11.84 min was initially quantified as beta-carotene, however closer inspection suggests that this carotenoid is not beta-carotene. This compound only appears when tetra-cis-lycopene is present in a tomato and does not appear in red tomatoes. Hence it is another compound adding to the synergistic mix within tetra-cis-lycopene tomatoes that will be influencing the health benefits available. We would welcome any information to help us identify this compound. The white colour represents high absorption and various colours represent intermediate absorption.

UHPLC contour chromatograms of ‘Moonbeam’.
The carotenoid with a retention time of 11.84 min was initially quantified as beta-carotene,
however, closer inspection suggests that this carotenoid is not beta-carotene.

‘Wally’s Spanish’ Tomato

This large beefsteak type orange tomato, purported to be of Spanish origin tested with high levels of tetra-cis-lycopene as well as the highest levels of phytoene; phytofluene and zeta-carotene in our 2021 results. This is a beautiful and tasty tomato for anyone liking a larger meaty tomato.

‘Golden Bell’ Tomato

This tomato continued to perform well and showed the second equal highest level of tetra-cis-lycopene as well as good levels of phytoene; phytofluene and zeta-carotene.

The ‘Oracle’ Tomato Selections

Several years ago, we had a ‘volunteer’ tomato that grew for us and it tested with the highest level of beta-carotene that we had seen. We named it ‘Golden Eye’. In 2020 we made two selections from this variety and named them ‘Golden Eye Improved’ and ‘Oracle’. Then in 2021 these plants morphed into a wider range and a few of the notable selections are ‘African Oracle’; ‘New Oracle’; ‘Optical’; ‘Oracle 1 SBO’ and ‘Red Oracle’.

‘African Oracle’ is an anomaly in that it has flipped from being high in beta-carotene to being higher in tetra-cis-lycopene as well as still containing a relatively high level of beta-carotene. In theory this is not possible because if you look at the biosynthesis pathway for carotenoids, what you see is this: Tetra-cis-lycopene -> all-trans-lycopene -> beta-carotene

The first step is converted by carotenoid isomerase, and the second two steps by lycopene beta cyclase (to make two rings on beta-carotene). Tangerine type tomatoes have non-functional carotenoid isomerase, or get stuck and don’t proceed to all-trans-lycopene, so it is hard to understand how you would get beta-carotene, unless you had only a partially functional carotenoid isomerase, but to our knowledge that is not something that has been seen before. (1)

‘New Oracle’ – This strong growing disease-resistant plant produced abundant golden cherry tomatoes that contained very high levels of beta-carotene as well as excellent levels of folate. (The folate levels were considerably higher than a standard red supermarket tomato). Naturally occurring folate, such as in these tomatoes is more bioavailable than the synthetic form of folic acid.

‘Optical’ – This version produced larger cherry tomatoes that contained high levels of beta-carotene.

‘Oracle 1 SBO’ – Small bright orange currant-sized fruit that tested with the highest level of beta-carotene and significant polyphenol concentrations for ten out of thirteen of the polyphenol compounds tested for.

‘Red Oracle’ – Although we stopped growing red tomatoes several years ago when we realised that the all-trans-lycopene they contain was not bioavailable when eaten raw and the evidence became obvious for the greater potential of benefit from orange tomatoes that contained tetra-cis-lycopene, occasionally we find a plant where the fruit has naturally crossed and become red. Usually we would reject those, however last year we sent two away for testing and ‘Red Oracle’ tested with very high levels of all-trans-lycopene and excellent levels of folate (similar to ‘New Oracle’).

Note; Our thanks to Dr Jessica Cooperstone, Assistant Professor, The Ohio State University for her assistance with helping us understand the biosynthesis pathway for tomato carotenoids

Process that we use further explanation.

We know that just the presence of a person in a laboratory can and does influence the outcome of an experiment. In working with plants, we are beginning to understand that humans have for thousands of years before us developed a deep respect for the plant kingdom. They learnt to communicate with plants and realised that there were also other life forms that existed and worked with the plants that were beyond the range of normal sight. These elemental beings (or nature spirits) exist at a higher vibration of frequency than physical matter upon the earth.

In the past it was understood that for there to be harmony and balance in the world, then humans needed to behave with respect to all other life forms. Practices (or rituals) were created so that food and medicine was grown and harvested and consumed in a respectful manner. For instance, asking permission by thought when about to plant seeds, or transplanting. Communicating to the plants before pruning or harvesting. Conveying gratitude and appreciation before eating a meal. Fragments of these traditions have survived, but largely they have not and the holistic understanding that all cultures in the world once had has largely been overwhelmed by modern Western reductionist science, that itself has largely been taken over by the influence of post-industrial mega-business.