Key takeaways:
Phytochemicals are compounds found in plant-based foods. Eating a rainbow of fruits and vegetables is the best way to ensure you’re getting these important nutrients.
Tens of thousands of phytochemicals have already been identified. And scientists are learning more about them every day.
Phytochemicals appear to be protective against heart disease, cancer, Type 2 diabetes, and neurological diseases.
When you have a sip of hot cocoa or munch on a handful of walnuts, you’re getting more than just a tasty snack. You’re getting a healthy dose of plant substances called phytochemicals, or phytonutrients.
Although research on phytochemicals is still limited, studies have shown that these compounds boast a range of benefits. They are associated with sharper vision and a reduced risk of heart disease, cancer, and neurodegenerative diseases like Alzheimer’s and Parkinson’s.
What are phytochemicals?
Phytochemicals are bioactive chemical compounds that occur naturally in plant-based foods. They have antioxidant properties, which means they can neutralize harmful free radicals. Free radicals are unstable molecules that can damage cell components, including the membrane, proteins, and DNA.
Phytochemicals aren’t essential nutrients for the body the way vitamins and minerals are. But they do offer health benefits. In fact, phytochemicals are one of the reasons why certain plant-based foods are known as functional foods. Functional foods provide health benefits beyond calories and macronutrients. For example, these foods might have gut-boosting or anti-inflammatory benefits.
Some plant-based functional foods that are regularly touted for their health benefits are green tea and dark chocolate.
Examples of phytochemicals
About 10,000 different phytochemicals have already been identified, and scientists believe there are many more out there. Below are just a few examples of phytochemicals that have been well researched.
1. Polyphenols
Polyphenols are phytochemicals that are found in:
Fruits
Vegetables
Tea
Coffee
Dark chocolate
You don’t have to try very hard to find them because they’re in just about every plant-based food. Their main function is as an antioxidant.
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Red wine has a particularly high polyphenol concentration. But while earlier research showed moderate consumption of red wine to raise high density lipoprotein (HDL) or “good” cholesterol levels, many of these studies were flawed. Drinking any type of alcohol is associated with health issues. So if you don’t already drink wine or are sober curious, don’t start.
2. Flavonoids
Flavonoids, which are one of the more well-known phytochemicals, are also abundant in just about every plant-based food, especially in healthy vegetables and fruits.
Flavonoids are a type of polyphenol that has anti-inflammatory and antioxidative properties. They may protect against:
Heart disease
Alzheimer’s
3. Isoflavones
Isoflavones are a type of flavonoid that appears to have antioxidant, antimicrobial, and anti-inflammatory properties.
They have also been shown to have anti-cancer properties, especially when it comes to breast cancer. However, the relationship isn’t straightforward. As some studies (mostly involving rodents) have shown, the compounds can also promote tumor growth. More research is needed to understand the exact benefits and potential risks.
4. Carotenoids
Carotenoids are examples of phytochemicals with notable antioxidant properties. They give yellow, red, and orange fruits and vegetables their color and are abundant in tomatoes and pumpkin. Carotenoids contribute to sharp vision and healthy cognitive function.
Which foods are rich in phytochemicals?
Phytochemicals are found in all plant-based foods, including:
Fruits
Vegetables
Legumes
Grains
Beans
Nuts
Seeds
Herbs and spices
The best way to get a variety of phytochemicals is to eat many different kinds of fruits and vegetables. Keep in mind, the different colors of fruits and vegetables represent different phytochemicals. So aim for a mixture of colors and to fill half your plate with fruits and vegetables at each meal.
Benefits of phytochemicals
Observational studies suggest that eating five daily servings of fruits and vegetables — which are rich in phytochemicals — is associated with lower risk of death from heart and respiratory illnesses.
There is also promising evidence that phytochemicals can potentially help:
The functioning of the immune system
Protect cells and DNA from damage that may lead to cancer
Reduce inflammation
Slow the growth rate of some cancer cells
Regulate hormones
Protect eye health and vision
Nourish skin and bone health
Maintain a healthy weight
But it’s important to note that what we know about phytochemicals is largely based on animal studies and lab studies. Studies on phytochemicals that involve humans tend to be narrow and limited to specific food sources in distinct populations.
This is because foods that contain these compounds also contain a variety of vitamins, minerals, and other nutrients. So it can be difficult to pinpoint a single phytochemical as the reason for a health benefit. Plus, health benefits found in nutrition studies can also be a result of lifestyle factors.
Can you have too many phytochemicals?
There is not currently a recommendation for how much of these compounds you should consume. But the amount of phytochemicals in food sources should be enough.
Talk to your healthcare provider, pharmacist, or dietitian before taking any supplements. Sometimes, supplements deliver a megadose of a nutrient that can be too much for the body to handle. They are also not monitored by the FDA, so they may not contain exactly what they say they do. And it’s best to get your phytochemicals from foods, not supplements, anyway.
The bottom line
Plant-based foods like fruits, vegetables, whole grains, and beans are full of phytochemicals. Filling half your plate with fruits and vegetables in a variety of colors is the best way to ensure you’re reaping the potential benefits of phytochemicals. But you can still pack these nutrients in by starting small — like adding some fruit for breakfast and a side of vegetables at dinner.
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References
Chiva-Blanch, G., et al. (2013). Effects of wine, alcohol and polyphenols on cardiovascular disease risk factors: Evidences from human studies. Alcohol and Alcoholism.
Ganesan, K., et al. (2017). A critical review on polyphenols and health benefits of black soybeans. Nutrients.
Grosso, G., et al. (2016). A comprehensive meta-analysis on dietary flavonoid and lignan intake and cancer risk: Level of evidence and limitations. Molecular Nutrition and Food Research.
Hammond, B. R., et al. (2022). The influence of the macular carotenoids on women’s eye and brain health. Nutritional Neuroscience.
Lang, T. (2007). Functional foods. BMJ.
Liu, Y., et al. (2013). Dietary flavonoids intake and risk of type 2 diabetes: A meta-analysis of prospective cohort studies. Clinical Nutrition.
National Eye Institute. (n.d.). Age-Related Eye Disease Studies (AREDS/AREDS2).
National Institutes of Health. (2021). Fruit and vegetable consumption reduce risk of death.
Panche, A. N., et al. (2016). Flavonoids: An overview. Journal of Nutritional Science.
Sivakumar, D., et al. (2018). A comprehensive review on beneficial dietary phytochemicals in common traditional Southern African leafy vegetables. Food Science and Nutrition.
U.S. Department of Agriculture. (n.d.). What is MyPlate?
Wei, C., et al. (2022). Association between the phytochemical index and overweight/obesity: A meta-analysis. Nutrients.
Yu, J., et al. (2016). Isoflavones: Anti-inflammatory benefit and possible caveats. Nutrients.
