What are Phytochemicals and Are You Getting Enough? 

Have you heard of the term “phytochemicals” before? Maybe you’re wondering what it means. This article will answer the question “what are phytochemicals?” It also shares where and how to get phytochemicals in your plant-based diet. 

What Are Phytochemicals? 

Phyto – means something of plant origin. Phytochemicals refer to non-nutrient compounds in plants that have a biological effect. These chemicals are usually made by plants for their own self-defense. Researchers are discovering that they may benefit human health as well. 

Plant-based foods such as nuts, vegetables, whole grains, fruits, and legumes contain thousands of phytochemicals. The structures of these phytochemicals determine their function in the human body. This is an area of active research. To date, we only know a fraction of these chemicals and their potential health impacts.

See Table 1 for selected classes of phytochemicals and their food sources. 

Class of Phytochemical	Sample Chemical(s)	Food Sources
Flavonols	Quercetin	Red onions, kale, apples, parsley, sage, tea
	Kaempferol	Apples, grapes, tomatoes, green tea, potatoes, onions, broccoli
Flavanones	Hesperetin	Lemons and sweet oranges
Anthocyanins	Malvidin	Blueberry, raspberry, black rice, and black soybean
Isoflavones	Genistein	Soybeans
	Daidzein	Soybeans
Chalconoids	Ellagic Acid	Walnuts, pecans, cranberries, raspberries, strawberries, grapes
	Curcumin	Curcuma longa (turmeric)
	Caffeic Acid	Coffee, thyme, sage, spearmint
	Resveratrol	Skin of grapes, blueberries, raspberries, mulberries
Flavanols	Catechin	Tea, wine, cocoa
	Epigallocatechin gallate	Tea, apple skin, plums, onions, hazelnuts, pecans, and carob powder
Carotenoids	Lycopene	Tomato
	Carotene	Sweet potato, carrots, mustard greens, apricots, asparagus, broccoli
Lipids	ß-Sitosterol	Vegetable oil, nuts, avocados
Betacyanins	Betanin	Beets, Swiss chard, Opuntia cactus
Glucosinolates	Glucoraphanin	Broccoli
	Sinigrin	Brussels sprouts, cabbage, and cauliflower

Table 1: A list of select phytochemicals and their food sources.

What do Phytochemicals do? 

Intake of certain phytochemicals is associated with reduced risks of chronic illnesses. There are many different phytochemicals, and many ways they may help protect our bodies. Some examples of phytochemicals are isoflavones, flavonols, glucosinolates, carotenoids, and flavanols. 

Benefits of Phytochemicals: Isoflavones 

Isoflavones are phytochemicals found in soy. They include genistein and daidzein. Experimental evidence shows that genistein interferes with cancer cells’ life cycles through interactions with their DNA. The link between isoflavone consumption and reduced cancer rates is backed up by large scale human studies. The rates of breast and prostate cancers are lower in countries with high consumption of soy.

High intakes of soy foods are also associated with decreased coronary artery disease (CAD). In CAD, cholesterol in the blood forms plaques or fatty deposits inside blood vessels. As these deposits build up in our arteries, a major event like a heart attack is more likely to occur. Cell studies show that isoflavones can reduce plaque build-up inside blood vessels. With this action, isoflavones may help reduce the risks of heart disease. 

Benefits of Phytochemicals: Flavonols 

For lower risks of lung cancer and cardiovascular disease, you may want to eat more foods that contain flavonol quercetin. In Hawaii and Finland, higher quercetin consumption is associated with lower risks of lung cancer. A diet high in quercetin helps to maintain the function of your immune system and reduces the potential for cellular damage in your body. Higher intake of quercetin is also correlated with lower cholesterol levels. Additionally, It has been shown to help reduce blood pressure in patients with high blood pressure. You can find quercetin in red onions, kale, parsley, sage, tea, and apples. 

Benefits of Phytochemicals: Glucosinolates 

Glucosinolates are phytochemicals found in cruciferous vegetables like broccoli, cabbage, and cauliflower. These phytochemicals can help transform toxic compounds into less harmful ones that eventually leave the body. Broccoli, Brussels sprouts, and red cabbage are high in glucosinolates. In fact, a diet high in cruciferous vegetables is more effective in cancer prevention than a diet high in vegetables and fruits in general. 

Benefits of Phytochemicals: Carotenoids 

The carotenoid lycopene is associated with lower risks of breast, colon, and gastric cancers. Research suggests that lycopene stops the growth of breast cancer cells in vitro. This phytochemical is found most commonly tomato and tomato products. Lycopene also improves the function of blood vessels, which helps to lower risks of cardiovascular disease. 

Benefits of Phytochemicals: Flavanols 

Cocoa is a particularly rich source of flavanols, including epicatechin. A 2016 systematic review shows that cocoa flavanols can improve the function of blood vessels, blood glucose metabolism, and lipid metabolism. There is also evidence that doses of 900 mg or more of cocoa flavanols may decrease blood pressure. 

Are You Getting Enough Phytochemicals? 

Currently, the government has not set a standard for “sufficient phytochemical intake.” This is because unlike most vitamins, there are no clear indications for phytochemical deficiency. For example, if a person has scurvy, it is due to the lack of vitamin C. However, if someone was diagnosed with coronary artery disease, it’s usually due to multiple risk factors rather than the lack of a specific phytochemical. 

Regardless, there is ample evidence that phytochemicals likely contribute to chronic disease prevention. So what is the best way to reap their benefits? 

Based on our current understandings, eating a variety of plant-based foods seem to be the most effective. Isolated phytochemicals taken as supplements often do not lead to the same health benefits compared to a diet composed of phytochemical-rich foods. It is believed that the biological effects of phytochemicals can be impacted by other phytochemicals, vitamins, minerals, and macronutrients eaten at the same time. A number of these mixtures provide enhanced effects against chronic disease processes and cancer cell growth. This is consistent with the findings of large-scale observational studies. People who eat more vegetables, fruit, nuts, and whole grains, have a lower risk for chronic illnesses. 

Tips for Optimizing Phytochemical Intake

Phytochemicals are widely distributed across vegetables, fruits, whole grains, pulses, and nuts. Increasing your intake of plant-based foods is perhaps the most effective way of increasing phytochemical intake.

Consider adding carrots, broccoli, and onions to soups, casseroles, or pasta. Using soy milk for cereal in the morning, and choosing a snack of grapes and dark chocolate can help you get your fill too! 

Furthermore, the skins of the fruits, nuts, and the bran of whole wheat have high amounts of phytochemicals. This may be a reason to leave the skins on when eating apples and to choose whole-grain wheat products when you can. 

How do you prioritize phytochemical-rich foods in your diet? Please comment below!

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