The Health Potential of the ‘Real’ Tomato

The Heritage Food Crops Research Trust is a very small charitable Trust in New Zealand that investigates the health properties of fruit and vegetables in order to find the very best medicinal foods for human health. To date, we have concentrated on apples, tomatoes and beans.

We wish to find the truth about what foods are best for our health. The data we have gathered on tomatoes clearly shows some of the old heirloom varieties have substantially higher levels of beneficial compounds than modern hybrid varieties.

Our direction has been influenced by our earlier work on apples, which indicated that there must be a flaw in modern breeding programmes whereby breeding criteria (and possibly other factors) led to lower levels of beneficial compounds in modern bred apples. Accordingly we have striven to find the oldest tomato varieties available anywhere in the world. Our work highlights the accelerated contamination of the gene pool that has happened in the past hundred years.

Tomatoes: the ‘golden fruit’

We are seven years into our tomato study. Our research on apples and tomatoes has shown the importance of heirloom (heritage) and old seedling varieties that contain much higher levels of beneficial compounds compared to modern, commercially bred varieties. For instance, within the wonderful diversity of colours, shapes and sizes of heirloom tomatoes, are a rich assortment of carotenoids and polyphenolic compounds. This includes varieties with good levels of specific medicinal compounds such as lycopene, recognised in a number of reputable studies to reduce the incidence of heart disease and certain cancers.

In our search for the best medicinal tomato, we are trying to find a tomato that has retained the purity of its genetic blueprint over a considerable period of time; a variety that has not been changed through human manipulation. We believe that we have found just that in some heirloom orange tomatoes, varieties we think are closely linked to the ‘golden fruits’ or pomodoro that appear in the 1544 herbal of Matioli. They were the first tomatoes introduced to Europe following Hernan Cortes’s conquest of Mexico (and tomatoes are still known by that name today in Italy). Our hypothesis is that these tomatoes will provide superior health benefits.

Because the health benefits of lycopene are widely recognized in scientific literature, it is one of the key compounds we looked for in the chemical analysis of our heirloom tomato samples. However the all-trans-lycopene present in today’s red tomatoes is a molecule whose linear structure seems to hinder its absorption within the body. This is why we hear recommendations to cook tomatoes and combine them with fat, in order to improve our absorption of lycopene^[1]. This has always seemed to us to be unusual, given that natural food in its raw state is typically better for us, and each stage of processing of food does diminish the medicinal quality of that food.

Discovered: tetra-cis-lycopene

We became aware of studies at Ohio State University and the Agricultural Research Service in California on an heirloom tomato variety, “Tangerine”. These found an alternative form of lycopene they call tetra-cis-lycopene. (It is also known as prolycopene.) Its structure is more like the lycopene that circulates in human blood. Tomato sauces made from red and Tangerine tomatoes were tested on volunteers. They found that the tetra-cis-lycopene from the Tangerine variety was more efficiently absorbed by the body. Further, oxidative damage decreased after eating either of the sauces, but the effect was greater after eating the Tangerine tomato sauce.^[2]

This clearly indicates the superior benefit of consuming these orange tomatoes containing tetra-cis-lycopene in a cooked form. But what about raw? The research has not yet been done to find out how tetra-cis-lycopene behaves and is absorbed when eaten as a raw fruit. Nevertheless, based on the indicators, we are confident that it will be very well absorbed by the body when eaten raw. We will endeavour to obtain funding so that this research can be done.

Our findings

We now have data on over 300 tomato varieties. We found 12 varieties with tetra-cis-lycopene ranging from 1.01 to 5.36 mg/100g FW: all are heirlooms and distinctively orange in colour. We used a modern commercially bred hybrid tomato called “Daniella” as a control. This is one of the most popular commercial hybrid tomatoes in New Zealand and is an attractive red, regular sized, firm and prolific tomato. Its levels of medicinal compounds are very low!

Our research leads us to the hypothesis that traditional Solanum lycopersicon tomatoes were originally golden-orange in colour and contained tetra-cis-lycopene that is more easily absorbed in the human body and therefore of great benefit for human health.

We further hypothesise that tomatoes containing tetra-cis-lycopene have greater potential to improve human health, in particular by reducing the incidence of heart disease and certain cancers.

Extensive breeding of tomatoes over hundreds of years has led to the recessive gene in tetra-cis-lycopene being progressively bred out, replaced by the more dominant all-trans-lycopene we now find in tomatoes and red tomatoes in particular. This inadvertent consequence of tomato breeding has significantly diminished the modern tomato’s medical value. It is quite probable that there is no modern commercially bred hybrid tomato with this valuable tetra-cis-lycopene.

We consider the identification of tetra-cis-lycopene and its connection to the original pomodoro tomatoes a breakthrough in our understanding. From now on we will only grow these high-health golden-orange varieties.

The challenge we now face is how to maintain or even enhance the medicinal qualities of these varieties, without falling into the commercial (or perhaps ego-driven) trap of manipulation for the wrong reasons.

Competing interests

Our Trust contracts a scientist at a major New Zealand plant research organization to carry out the chemical analysis of our tomato samples. His attempts to generate some interest within his organisation in further research on tomatoes have been unsuccessful. He was told there were major commercial barriers to the establishment of a ‘new’ tomato, one being the yield: if a variety can’t produce 16 trusses of fruit, commercial growers are not interested. And even though the research on heirloom tomatoes clearly shows that they are superior for human health, they are perceived to be less productive and hence not worth growing. This of course ignores the quite different requirements of the many gardeners growing their own tomatoes in their backyard.

In the modern world we have given responsibility for growing food over to commercial interests, especially as we have become more time-constrained with work pressures, travel times and the complexities of modern day living. However as many are now realising, modern commercial growers use seeds and methods that conform to their specific criteria and needs. Maximising profit for business through increasing yields has come at the cost of nutritional and medicinal quality.

In our view, those breeding tomatoes have been completely unaware of the long-term implications of what they were doing. Only on examination of the results do we see the foolhardiness of the approach taken. It is impossible to quantify the adverse health outcomes arising from tampering with a healthy medicinal fruit for commercial reasons. If this is representative of the widespread breeding and manipulation of our food supply that has taken place, then we only have to look around us at the level of ill health in society today to see the consequences.

Fortunately there is a growing awareness of the need to take back responsibility and exercise control over our food supply once more. To this end we are very pleased to be members of various seed saving organisations and part of this wonderful, worldwide reawakening of understanding regarding food. It is indeed fortunate that there are dedicated individuals and groups who keep the remnants of our heirloom seeds alive, jewels we can turn to when these breeding mistakes are eventually detected.

Our emphasis on medicinal quality is not new. It is an ancient understanding, epitomised by the teachings of Hippocrates: that food is mankind’s medicine and contains within it all that is needed to keep people well.

1. Turning up the heat on tomatoes boosts absorption of lycopene
2. “Tangerine Tomatoes top reds in preliminary lycopene study”: Agricultural Research, February 2011