Phytonutrients (phyto = plants) are natural components of plants that serve as powerful defenders of health. They are responsible for giving plant foods their distinct colors, tastes, and smells as well as providing the plant with protection from pests and environmental stressors. In the human body, phytonutrients play a role in many beneficial processes including:
Hormone metabolism (promoting healthy estrogen metabolism)
Strengthening the immune system
Preventing damage to cells and stimulating the death of cancer cells – due to antioxidants
Improving cardiovascular health
Reducing risk of stroke, Alzheimer’s and Parkinson’s
Promoting healthy aging
More than 25,000 phytonutrients are found in plant foods. Fruits and vegetables are rich sources of phytonutrients, as well as whole grains, legumes, herbs, spices, nuts, seeds, and teas. In order to get the full benefit of phytonutrients, it’s important to incorporate these foods into your diet in their whole-food form (fresh is best, frozen is second, canned is last). Specific phytonutrients and their health benefits are associated with specific colors of foods, including red, orange, yellow, green, blue/purple/black, and white/tan/brown.
Incorporating a variety of phytonutrient rich fruits and vegetables every day is foundational to all food plans within functional medicine, as certain plants are medicine for chronic disease prevention and treatment.
Let’s take a look at the food rainbow and their benefits.
Red foods contain phytonutrients that may help reduce the risk for certain cancers, along with helping to protect the brain, heart, liver, and immune system.
Beans (Adzuki, Kidney, Red)
Sweet red peppers
Tomato (try to avoid seeds)
Examples of Red Food Phytonutrients:
Lycopene is a red-colored phytonutrient that may protect against cancers of the prostate, breast, and skin, and reduce the risk of heart attacks. It is typically found in tomatoes and tomato-based products such as tomato juice, spaghetti sauce, tomato soup, and tomato paste. It is also found in watermelon, pink grapefruit, and guava. It is best to cook tomato products so lycopene is more “available” to the body to be absorbed. It is also fat-soluble like many of the other carotenoids, and therefore requires fat together with cooking to optimize absorption into the body. An ideal combination would be making a cooked tomato sauce and adding olive oil or grass-fed butter/ghee.
Anthocyanins are phytonutrients you can find in red berries such as raspberries, sweet cherries, strawberries, cranberries, and in other red foods like apples (with skin), beets, cabbage, onion, kidney beans, and red beans. They help with reducing the risk of cancer and protecting the heart and brain.
(Other Beneficial Red Food Phytonutrients include: Anthocyanidins, Astaxanthin, Carotenoids, Ellagic Acid, Ellagitannins, Fisetin, Flavones, Flavonols, Flavan-3-ols, Flavanones, Luteolin, Lycopene, Proanthocyanidins, Quercetin)
Orange foods help protect the immune system, eyes, and skin, and reduce the risk for cancer and heart disease.
Source of vitamin A
Squash (acorn, buttercup, butternut, winter)
Examples of Orange Food Phytonutrients:
Beta-Carotene is important because it can turn into vitamin A in the body. Vitamin A has many functions such as promoting healthy vision, immune and inflammatory systems, cell growth, reproduction, and bone health. There are several plant compounds that convert to vitamin A in the body (called “carotenoids”) under the right conditions, and beta-carotene is just one.
Most food sources of vitamin A are of animal origin such as seafood, eggs, fish, and dairy products. Therefore, if you are a vegan/vegetarian, it is important to eat high-carotenoid-containing foods which can also be red, yellow, and green. Additionally, it may not be enough to have carotenoids be your sole source of vitamin A as there are a number of factors that can limit the conversion of carotenoids into beta-carotene such as genes, digestive issues, excessive alcohol use, toxicity, and certain prescription or over-the-counter medications. To get more carotenoids like beta-carotene from your food, cooking these foods is important. Cooking carotenoid-containing vegetables that are higher in fiber frees the carotenoids from the food matrix (including the fiber). Then fat is needed to support absorption since carotenoids are “fat-soluble” or they require the presence of fat to become more available to the body. Consuming them with a little olive oil or grass-fed butter/ghee would be ideal.
Bioflavonoids are found in oranges, grapefruit, tangerines, clementines, peaches, nectarines, and even yellow-colored foods like lemons and pineapple. In contrast to beta carotene, bioflavonoids are water-soluble, so they don’t require cooking. Bioflavonoids are important because they work together with vitamin C to reduce the risk of heart attacks and cancer, and help maintain strong bones/teeth, healthy skin, and good vision. It is often the case in nutrition that you see vitamins, phytonutrients, and minerals working together in synergy to create the best effect.
(Other Beneficial Orange Food Compounds include: Alpha-carotene, Beta-carotene, Beta-cryptoxanthin, Bioflavonoids, Carotenoids, Curcuminoids, Naringenin)
Yellow foods are beneficial because they contain compounds that are anti-cancer, anti-inflammatory, and may protect the brain, heart and vasculature, eyes, and skin.
Banana Bell peppers
Examples of Yellow Food Phytonutrients:
Lutein & Zeaxanthin - Similar to lycopene and beta-carotene, lutein and zeaxanthin are both carotenoids. These two carotenoids are not just found in yellow foods but in green foods like kale and spinach as well (although they are not visible to the eye). A good yellow food source of lutein is corn. Since corn is in many foods as a processed ingredient and mostly GMO, it is preferable to get your corn as corn-on-the-cob or the whole kernel form and look for GMO free. Keep in mind that corn tends to be starchy and can increase your blood sugar, so you will want to have it in a larger meal containing other foods that are higher in fiber, protein, and healthy fats. Like the other carotenoids, lutein and zeaxanthin are fat-soluble so they need fat for absorption. Cooking corn-on-the-cob and eating it with a little organic grass-fed butter would be a good option.
(Other Beneficial Yellow Food Compounds include: Lutein, Rutin, Zeaxanthin)
Green foods contain compounds that are anti-cancer, anti-inflammatory, and may protect the brain, heart and vasculature, liver, and skin. One of the unique attributes of some green foods is that they help support liver function as well as assisting with hormone balance.
Greens (arugula, beet, chard, collard, dandelion, kale, lettuce, mustard, spinach, turnip)
Examples of Green Food Phytonutrients:
Glucosinolates are the class of phytonutrients which give cruciferous vegetables (also known as the Brassica vegetables) their anti-cancer properties. Glucosinolates give some of these vegetables their stinky sulfur aroma. But that sulfur comes in handy as it supports the liver in ridding the body of toxins. Chopping or chewing cruciferous vegetables converts glucosinolates into active compounds called isothiocyanates (indole-3-carbinol, sulforaphane, and many others). These phytonutrients change the way estrogen is metabolized or broken down in the body. As a result, eating these vegetables is associated with the decreased risk of hormone or estrogen related cancers such as breast and uterine cancer.
The following green vegetables are included in the cruciferous family: arugula, bok choy, broccoli, broccolini, Brussels sprouts, cabbage, Chinese cabbage (napa), collard greens, kale, kohlrabi, mustard greens, and watercress.
Phytosterols, or plant sterols, are compounds that look like cholesterol, but they are not cholesterol. There are many different types of phytosterols, and they are known to be beneficial in helping to reduce LDL-cholesterol (the not so good kind). There may also be some immune system benefits of these compounds. Good sources of phytosterols from green foods include avocado, lettuce, and olive oil.
Catechins are one of the bitter compounds found in green tea. The most famous catechin from green tea is called epigallocatechin gallate (or EGCG). Having just one cup of green tea a day has been shown to reduce the risk of breast cancer by 50%. It also supports bone health, boosts the immune system, supports heart health, and can help balance blood sugar.
(Other Beneficial Green Food Compounds: Catechins, Chlorogenic acid, Chlorophyll, Epigallocatechin gallate, Flavolignans, Folates, Glucosinolates, Hydroxytyrosol, Indole-3-carbinol, Isoflavones, Isothiocyanate, Oleocanthal, Oleuropein, Phenolic diterpenes, Phytosterols, Phenols, Phenylethylisothiocyanate, Silymarin, Sulforaphane, Tannins, Theaflavins, Thearubigins, Tyrosol)
Blue/Purple/Black foods from nature contain compounds that are anti-cancer, anti-inflammatory, and may protect the brain, heart, and vasculature. This is the category that many people eat the least from on a daily basis. It is unfortunate because blue/purple food compounds are especially important for the brain, protecting it from damage and promoting healthy cognition and memory.
Berries (blue, black, boysenberries, huckleberries, marionberries)
Rice (black, purple)
Examples of Beneficial Blue/Purple/Black Food Phytonutrients:
Resveratrol is a popular purple phytonutrient that is well known due to its effects on supporting and promoting a healthy aging process. It does this by reducing inflammation and blood sugar, and is beneficial for the cardiovascular system. Food sources of resveratrol include grapes (in the skin), and grape-derived products like red wine (preferably low sugar and organic). Less rich sources include peanuts (especially the skin) and peanut butter, dark chocolate, and blueberries.
Pterostilbene is a phytonutrient that resembles resveratrol and is found in blueberries and grapes. There is some animal research that suggests it wards off cancer, keeps cholesterol and triglycerides low, and may help with preserving cognition. There may also be positive effects on blood sugar.
(Other Beneficial Blue/Purple/Black Food Compounds include: Anthocyanidins, Hydroxystilbenes, Procyanidins, Pterostilbene, Resveratrol)
White/Tan/Brown Foods- This category includes nuts, fruits, vegetables, legumes, spices, seeds, and whole grains NOT processed breads, pastas, and pastries. These healthy sources of white/tan/brown foods have anti-cancer and anti-inflammatory properties. Similar to the green foods, there are certain compounds that can assist with liver and hormone health.
Legumes (chickpeas, dried beans or peas, hummus, lentils, peanuts, refried beans)
Nuts (almonds, cashews, pecans, walnuts)
Seeds (flax, hemp, pumpkin, sesame, sunflower)
Tea (black, white)
Whole grains (barley, brown rice, oat, quinoa, rye, spelt, wheat)
Examples of Beneficial White/Tan/Brown Food Phytonutrients:
Allicin is one of garlic’s medicinal components that may contribute to its anti-cancer, blood pressure-lowering effects. To maximize the production of allicin, it is recommended that you let the crushed or chopped garlic sit for 5-10 minutes before cooking it or adding anything to it. It is also this compound that gives garlic its anti-bacterial and anti-viral properties.
Lignans are fiber-related phytonutrients that act as antioxidants and phytoestrogens, or plant compounds with weak estrogen activity. A popular food with high amounts of lignans is flaxseed. Other food sources of lignans are sesame seeds, sunflower seeds, cashew nuts, and peanuts. Lignans are anti-inflammatory, promote healthy blood vessels, and act as anti-cancer agents, especially hormone related cancers like breast and prostate cancers. One of the ways that lignans may be helpful in reducing cancer is by activating certain enzymes in the liver responsible for deactivating toxins in the body.
(Other Beneficial White/Tan/Brown Food Compounds include: Allicin, Allyl sulfides, Cellulose, (fiber), Lignans, Lignins, Sesamin, Sesamol, Tannins, Terpenoids, Theobromine)
So, How Can I Get More Phytonutrients in My Diet?
First observe the colors you currently eat. You will want to shift to getting the broader spectrum and more color variety when you can. It’s common to get stuck into a rut of eating the same foods over and over again. Try to eat the rainbow!
Fruit and vegetable smoothies for breakfast or lunch.
Try new fruits and veggies every week and keep them where you can see them.
Keep pre-cut fruits and vegetables on the top shelf of refrigerator.
Keep a fruit bowl on kitchen counter, table, and desk at work.
Choose fruit for dessert (fruit kabobs, berry compotes, fruit salads, cooked apples and cinnamon, etc.).
Consume dishes with lots of vegetable variety (e.g., soups, stir-fry, chilis, tacos).
Use vegetable-based sauces.
Choose darker vegetables over lighter to maximize nutrient content (spinach or arugula over romaine).
Switch from mashed white potatoes to sliced or mashed carrots, sliced or mashed sweet potatoes or mashed cauliflower.
Include veggies in your omelets/scrambled eggs or make pre-made crustless mini quiches for the week (spinach, bell peppers, tomato, garlic, onions, asparagus, broccoli, etc.)
Add rinds of oranges or lemons to water, chicken, and fish.
Boost your salads with lots of colors (tip: briefly sauté veggies first before adding to bed of greens for best digestion and nutrient absorption).
Be generous with your use of spices and herbs.
Rainbow Smoothie - Makes 2 servings (1 serving = 8–10 ounces)
½ cup (cold) green tea
1 cup hemp or almond milk (unsweetened)
1–2 tablespoons chia seeds, whole or ground
¼ teaspoon cinnamon
⅛ teaspoon ginger (dried) or ½ teaspoon fresh ginger, minced
1 tablespoon fresh lemon juice
1 teaspoon maple syrup or 1 teaspoon stevia
½ cup (no sugar added) frozen blueberries
½ cup (no sugar added) frozen strawberries
½ cup (no sugar added) frozen mangoes
1 cup packed baby spinach
*Add ¼ to ½ cup ice to increase thickness if desired
Add prepared green tea, hemp or almond milk to blender. Then add the rest of the ingredients in the order listed ending with baby spinach. Blend at very low speed until ingredients are mixed then gradually increase speed to high and blend well for 1 minute. Serve immediately. (If unable to serve immediately, please omit chia or other seeds as gelling will occur and it will be less palatable.)
Options: Add 1–2 scoops protein powder, 1–2 tablespoons nut butters or ground flax or hemp seeds or a combination of these options to add quality protein, healthy fats and fiber to this smoothie. If using fresh fruit be sure to add ½–1 cup ice to mixture to desired thickness.
Magic Mineral Broth - Serving size: 6 quarts
6 unpeeled carrots, cut into thirds
2 unpeeled yellow onions, cut into chunks
1 leek, white and green parts, cut into thirds
1 bunch celery, including the heart, cut into thirds
4 unpeeled red potatoes, quartered
2 unpeeled Japanese or regular sweet potatoes, quartered
1 unpeeled garnet yam, quartered
5 unpeeled cloves garlic, halved
½ bunch fresh flat-leaf parsley
1 8-inch strip of kombu
12 black peppercorns
4 whole allspice or juniper berries
2 bay leaves
8 quarts cold, unfiltered water
2 teaspoons sea salt
1. Rinse all of the vegetables well, including the kombu. In a 12-quart or larger stockpot, combine the carrots, onions, leek, celery, potatoes, sweet potatoes, yam, garlic, parsley, kombu, peppercorns, allspice berries, and bay leaves. Fill the pot with the water to 2 inches below the rim, cover, and bring to a boil.
2. Remove the lid, decrease the heat to low, and simmer for at least 2 hours. As the broth simmers, some of the water will evaporate; add more if the vegetables begin to peek out. Simmer until the full richness of the vegetables can be tasted.
3. Strain the broth through a large, coarse-mesh sieve (remember to use a heat-resistant container underneath), then add salt to taste.
4. Let cool to room temperature before refrigerating or freezing.