I was at the lab early to set up a new experiment.
I started by adding the drug Paclitaxel to a plate of rapidly dividing pancreatic cancer cells. I was hoping to understand how gene mutations lead to chemotherapy resistance.
When I checked on the cells a few hours later, it looked like a bomb had gone off. The aggressive cells were shriveled up, floating lifelessly.
“All this mayhem caused by a little chemical found in tree bark!” I thought.
It gave me a new respect for plants. They can’t run or hide from predators, but they certainly know how to defend themselves.
Plants carry an arsenal of molecules that are toxic to many bacteria, insects, and in some cases, even humans. Like cyanide found in bitter almonds and the coniine found in hemlock.
But for the most part, these fierce compounds help humans more than they harm us. In fact, modern medicine has put many of them to good use. They’re in drugs that treat malaria, asthma, heart failure and Parkinson’s disease.
And these molecules are somewhere else that you probably don’t expect: in our everyday foods.
We call these special compounds phytochemicals.
Phytochemicals give wild blueberries their color (anthocyanin), chili peppers their spice (capsaicin) and coffee its buzz (caffeine).
Thousands of phytochemicals have been discovered in vegetables, fruits, grains, beans and seeds. In fact, every plant we eat has its own phytochemical fingerprint. Pumpkins are rich in carotenoids, broccoli sprouts contain loads of isothiocyanates, and flaxseeds are packed with lignans.
For every phytochemical that is known, experts believe that there are likely hundreds more yet to be discovered.
Phytochemicals interact with our biological pathways in countless different ways. Nevertheless, they all seem to share similar beneficial effects. They act as antioxidants, prevent DNA damage, inhibit tumor cell growth and tamp down inflammation.
The way this works is simple. Phytochemicals apply stress to our cells. But it’s usually a healthy stress, like lifting weights or going on a run. This keeps our cells in great shape.
When we sustain damage by UV radiation, oxidation, or environmental toxins, it’s phytochemicals that ensure our cells are strong and ready to heal right away. This explains how these remarkable nutrients protect us from wide range of chronic diseases.
For instance, broccoli has several powerful phytochemicals that reduce the risk of Alzheimer’s disease, lower insulin resistance, and protect against breast cancer.
The phytochemicals abundant in tomatoes decrease prostate cancer risk and also play a role in preventing heart disease and dementia.
Aside from warding off disease, phytochemicals are essential ingredients to unlocking our best self. Recent studies in brain health show that a variety of phytochemicals can influence cell signaling and gene expression in neurons, leading to changes in brain architecture as well as blood flow. As a result, phytochemicals appear to promote memory, learning and cognitive function.
Much of the power of phytochemicals comes from the way they work together. Phytochemicals exhibit real synergy. Like a bunch of Ewoks defending their forest home, they multiply their effects so that even the tiniest ones count.
One laboratory study combined the phytochemicals of several fruits and found a much stronger anticancer effect compared to when each fruit’s phytochemicals were taken separately. Another showed that the phytochemicals in green tea and turmeric inhibit tumor growth together far more than they do apart.
Are you ready to get more of these nutrients in your diet? The simplest way is to eat a rainbow of fruits and vegetables. The actual pigments in these foods are phytochemicals that pack a mighty punch, and getting a diverse mix ensures we’re activating a broad range of protective pathways.
For most produce, we get peak nutrient-richness by eating them fresh. That said, finding truly fresh food can be a challenge. Supermarket produce can spend days or weeks in storage or transport. And all that time it spends sitting after harvest counts. Research shows that vegetables like spinach and green beans lose most of their Vitamin C content in less than a week, even when kept cool. Phytochemicals are often just as vulnerable to decay. So purchasing local, freshly-harvested produce is our best bet.
Buying flash-frozen fruits and veggies is a good alternative, since the low temperatures protect against nutrient oxidation. Cooking vegetables can also have advantages. Sautéing onion increases its quercetin content and roasting carrots makes its beta-carotene more easily absorbed.
Be sure to eat the fruit and veggie peels whenever possible. Plants tend to concentrate phytochemicals in their outer layer to provide defense where it’s needed most. The peel of an apple accounts for half of its anti-tumor activity. The potato skin is where almost all of its antioxidant activity resides.
Another way to load up on phytochemicals is by eating plenty of beans and whole grains. Try cooking them with different herbs and spices, like rosemary, oregano and clove. These are loaded with phytochemicals that give us an even bigger nutrient boost!
By now I hope one thing is clear: the phytochemicals in our food are very different from drugs at the pharmacy. Medicines are single compounds given at high doses. They target a single pathway for the treatment of a single disease. Meanwhile, a plant that we eat carries hundreds of phytochemicals at small concentrations. They interact with many pathways to protect us from many diseases over time. And the more we consume, the stronger the effect.
The complex interaction between phytochemicals and human biology means that there’s a lot we still don’t know. Science needs to keep pushing at the frontiers. The more deeply we understand phytochemicals, the better we’ll understand how food can sustain our long-term health.
For now, phytochemicals offer a window into the biological complexity that exists within food. They remind us to appreciate the way foods can nourish and heal. And they put us on the path to a nutrient-rich life.
Phytochemicals are special compounds that exist in all plants and broadly elevate our health.
Maximize your phytochemical intake to protect against obesity, heart disease, diabetes and cancer. Eat lots of diverse types of plants including fruits, vegetables, spices, herbs, beans, whole grains and seeds.