Leisha (this is an excerpt from my new upcoming book “Plant & Kitchen Alchemy“)
There is alchemy when a green tomato turns red. It may look as though the fruit is simply ripening, yet inside it an entire chemistry is rearranging. The green chlorophyll is disappearing, and the sugars and acids are finding a new balance. Volatile compounds create that unmistakable smell of a ripe tomato, while lycopene floods the fruit with red colour. Red is not simply decoration added at the end. It is evidence that something has happened, and lycopene is one of the alchemists.
Lycopene belongs to the carotenoid family, along with beta-carotene and many other plant pigments, but it has a personality of its own. Beta-carotene can be converted by the body into the fat-soluble vitamin A, but lycopene remains lycopene. Its long chain of connected double bonds is what gives the molecule its deep red colour and some very cool and unusual biological abilities.
Lycopene can interact with highly reactive forms of oxygen in our tissues, giving it its antioxidant power, but the story has grown far more interesting than describing lycopene as merely an antioxidant. It is comfortable in the fatty places of the body, including cell membranes, and it influences signalling connected with inflammation, cell growth and blood-vessel function. Human studies with tomato paste have even found measurable improvements in the function of the endothelium, the living inner lining of our blood vessels.
Lycopene has been found in skin, reproductive tissues, the prostate and the nervous system, and circulates through the blood carried in lipoproteins. Its ability to quench highly reactive oxygen molecules helps protect lipids and membranes, while its effects on cellular signaling take us into an entirely different level of the story. The same red molecule begins appearing in very different tissues, doing slightly different work depending upon where it lands.
The prostate is particularly interesting because lycopene actually accumulates there. Men eating tomato sauce have shown substantial increases in lycopene inside prostate tissue, and lycopene interacts with several of the signals involved in prostate growth, including androgen signaling, IGF signalling and inflammatory pathways. Tomato sauce studies have also found increased apoptosis in benign hyperplastic prostate tissue. Apoptosis is the body’s beautifully organised way of retiring cells when they are no longer meant to remain.
I have considered lycopene for prostate health for exactly this reason, especially for men experiencing an enlarging prostate. In one study of men with benign prostate enlargement, 50 grams of tomato paste a day for ten weeks was associated with a significant reduction in average PSA levels. Once again, the concentrated cooked tomato becomes much more interesting than something we simply put on pasta.
I have always struggled with cold sores from HSV-1, so lycopene is a bit of a hero for me here as well. HSV-1 has an extraordinary survival strategy. After the original infection it can retreat into sensory nerve cells, particularly the trigeminal ganglion, and remain there quietly in a latent state. Fever, stress, illness and exposure to strong sunlight are among the things that can wake it up again, which explains why that familiar tingling can suddenly appear when we are run down or after too much sun.
Cell-culture research with HSV-1 found that it interfered with viral activity and reduced the cell damage produced by the virus, with the strongest effect at the highest lycopene concentration tested. I have remembered that connection ever since, particularly because lycopene also concentrates in skin and tissues and has such an interesting relationship with oxidative stress. So, great for aging skin!
The red lycopene, however, is trapped inside the architecture of a raw tomato. Slice it and some of those compartments break open. Crush it and thousands more collapse. Put that crushed tomato into a warm pan and begin making a sauce or paste, and the lycopene begins opening up even further. Our kitchen alchemy changes the architecture the plant spent months building, making something previously tucked away inside the fruit increasingly accessible.
Then something even stranger and more wonderful happens. Some of the lycopene actually begins to change shape.
Fresh tomatoes contain lycopene predominantly in what is called the all-trans form, a relatively long and straight arrangement of the molecule. Heat causes some of those molecules to rearrange into various cis forms, giving the same lycopene molecule a slightly different geometry. Those cis forms can be incorporated more easily into the tiny fat-and-bile structures involved in digestion, helping make the lycopene more available for absorption.
Heat has not created a new nutrient. It has opened the tomato’s structure and rearranged some of its lycopene into forms our body can more readily access. The garden created the molecule, and now the kitchen has taken that molecule into another stage of its transformation. We are kitchen scientists making medicine.
This is alchemy of the plant and the kitchen together, and I love that. The tomato goes into the pot in one physical state and emerges carrying the same red pigment in a very different setting. Its cells have been broken open, some of its lycopene has shifted shape, and what had been held tightly inside the fresh fruit has become easier for our bodies to use. Cooking is not merely making the tomato softer. We are changing our access to what the plant made, essentially making stronger medicine with our food.
And we can see the transformation happening. As the tomato cooks, the bright red becomes deeper and darker. Sharpness softens while sweetness and savoury flavours intensify, and everything becomes richer. A bowl full of tomatoes slowly becomes a cup of sauce and, if we keep going, a few spoonfuls of thick red paste. That small amount is potent medicine.
Several tomatoes can disappear into a few spoonfuls of paste. We have broken open the fruit, altered some of the lycopene’s geometry, removed much of the water and concentrated what remains into a much smaller amount of food. The tomato has changed physically, chemically and even in the way our own body will encounter it.
Then we need to add fat. Lycopene is fat-soluble, so once tomato enters the digestive tract it does not move particularly well through that watery environment on its own. Fat in the meal, together with bile, helps gather carotenoids into tiny, microscopic structures called micelles. These tiny carriers bring lycopene close to the intestinal wall, where it can be absorbed, packaged into lipoproteins and carried through the circulation.
A spoonful of concentrated tomato cooked into butter suddenly makes beautiful, healthy, medicinal sense, and it is, honestly, quite delicious. We sell tomato butter at our cafe.
Perhaps our grandmothers did not need the word micelle to understand that tomatoes loved fat. They knew what happened when tomatoes met butter, cream, cheese, eggs or the rich fats of a meal, and the combination simply tasted complete. Chemistry gives us another glimpse into why those old kitchen pairings work so well.
The skin of the tomato is particularly rich in flavonoids and carotenoids, so I do not remove it when making sauces and pastes. Many recipes tell us to peel tomatoes, yet a smooth sauce can simply be blended with the skin included. There is valuable chemistry sitting in the very part we are so often instructed to throw away.
Lycopene also has company. Beta-carotene, phytoene, phytofluene, tocopherols and flavonoids including quercetin and rutin are traveling inside that same tomato. Phytoene and phytofluene sit very close to lycopene in the plant’s carotenoid pathway, yet they are almost colorless, so we do not see them announcing themselves in the way lycopene does.
Phytoene and phytofluene have their own little piece of alchemy. Their molecular structures allow them to absorb ultraviolet wavelengths of light, and both compounds are actually found in human skin. Studies using tomato-derived carotenoids have found increases in phytoene and phytofluene in the blood along with increased skin carotenoids, and researchers think these almost invisible tomato molecules contribute to the skin’s response to UV exposure.
Our skin appears to notice tomato chemistry very well. Research with tomato paste has found less UV-induced redness, less mitochondrial DNA damage, reduced activity of MMP-1, an enzyme involved in breaking down collagen, and increased deposition of procollagen I, one of the building blocks from which collagen is made. The food on the plate had travelled far enough through the body to change how the skin responded to sunlight and reducing the effects of agin skin. Perhaps the red removes the redness of skin!?
None of these compounds were assembled separately and dropped into the fruit one molecule at a time. Nature doesn’t do that. Lycopene, phytoene, phytofluene, beta-carotene, tocopherols and flavonoids were created together inside a living tomato, through the same roots, fed through the same soil food web, under the same sunlight and through the same season. Then we eat them together.
The relationships between all these compounds are still being unravelled, and separating the tomato into isolated pieces can make us miss part of its beauty. That, for me, is part of the point of looking closely at a tomato. It never grew as a single molecule. It grew as a living collection of compounds, each connected to the biology that built the fruit in the first place.
And, know we have information about lycopene and the brain, which gives the cooked tomato another standing ovation.
Lycopene can cross the blood-brain barrier and reach neural tissue, where its relationship with oxidative balance, inflammatory signaling and neuronal function becomes particularly fascinating. The red molecule we first watched appearing during ripening has now travelled a very long way.
Tomato paste is awesome brain food. A recent randomized crossover study had healthy adults between forty and fifty-five years old eat concentrated tomato paste every day for three months, averaging about 35 grams a day. Their plasma lycopene nearly doubled, while selective attention, concentration, processing speed and associative memory improved. The increases in blood lycopene were themselves correlated with improvements in concentration and processing speed.
Brain imaging showed changes in the way several neural networks were communicating as well. BDNF, brain-derived neurotrophic factor, also increased, although with considerable variation between people. BDNF is especially interesting because neurons use it for growth, maintenance, plasticity and their ability to form and remodel connections. Pretty cool when we are talking about a few spoonfuls of cooked tomato.
So the red pigment made by a ripening fruit moves from soil and plant, through our hands and the cooking pot, into the digestive tract, circulation, skin, prostate and brain. Along the way its form changes, our access to it changes, and then our own biology takes over the transformation. That is quite a journey for a tomato, and in the end some of what began in the soil has quite literally become part of us.
That is what makes the tomato such a perfect piece of kitchen alchemy. The tomato that entered the kitchen is not quite the tomato that reaches the gut, and what leaves the gut is something different again. Alchemy and transformation continue through every stage, with soil, microbes, plant, kitchen, digestion and our own microbiome each participating in what happens next. Once you have followed that journey from soil to sauce, from sauce to intestine and from intestine into blood, skin, prostate and brain, it becomes difficult to look at a spoonful of tomato paste in quite the same way. It is food as medicine, with the kitchen becoming part of the medicine-making.
From the Alchemist’s Kitchen
Garden Tomato Butter
- ½ cup butter, softened
- 3 tablespoons concentrated tomato paste
- 1 small clove garlic, very finely grated
- 1 tablespoon finely chopped fresh basil, oregano or thyme
- Pinch of mineral salt
- Freshly ground black pepper
- A little lemon zest, optional
- Tiny drizzle of honey if the tomatoes are particularly acidic.
- We also add basil as this compliments the tomato in the garden and in our mouth.
Melt about one tablespoon of the butter over very gentle heat and stir in the tomato paste. Warm it for two or three minutes, stirring as the paste darkens slightly and becomes fragrant. Remove it from the heat and allow it to cool for a few minutes.
Mix the warm tomato paste into the remaining softened butter with the garlic, herbs, salt and pepper. Add a little lemon zest for brightness or a tiny amount of honey if the paste needs its acidity softened, then taste and adjust.
Spoon the tomato butter into a small jar and refrigerate it, or roll it into a log and chill until firm. Melt it over eggs, potatoes, vegetables or mushrooms, stir a spoonful into soup, or simply spread it on warm bread.
