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.
The Secret to Our Health Lies in Older Varieties
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.
The underlying reasons for this significant difference 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 cultivated as varieties in Mexico. Those original tomatoes were named ‘Pomodoro’, which in Italian 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 the ‘Moonglow’ tomato and other golden/orange varieties that have been chemically analysed and shown to contain tetra-cis-lycopene are strains from those original golden fruit.
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).”
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.