Leafy greens are an essential ingredient in green smoothies.

• Leafy greens are superfoods! "Leafy greens are the best veggies!" — Dr Greger. We should strive to eat an abundance of leafy greens daily — their list of health benefits is too long! See Leafy Greens at NutritionFacts.
• Low oxalate leafy greens: Dr Greger encourages us to eat low oxalate leafy greens regularly and consume high oxalate leafy greens in smaller quantities. We should not eliminate high oxalate leafy greens completely; they are healthy whole foods, good for diversity of leafy greens in our food plates. For details, see Dr Greger's Optimum Nutrition Guidelines (search for 'low oxalate') and Kidney Stones.

  Three leafy greens have high oxalates: spinach, beet greens and chard. I eat these three sparingly. The leafy greens that I consume regularly are kale, collards, arugula, Brussels sprouts, red lettuce, and mixed greens. Of these, kale and collards are my favorites for making a green smoothie.

• Taste: Most people don't find leafy greens tasty. If you find leafy greens flavorful, you’re blessed! Most people are not so lucky and struggle to eat them in daily meals.

  Why are leafy greens not tasty? One explanation is that leafy greens have low calorie density (calories per kilogram) — see Calorie Density charts. For foods that give us so few calories, we’re physiologically wired to avoid them in the presence of foods that have higher calorie density. See this article Calorie Rich and Processed (CRAP) Foods for a scientific explanation.

  If we are somebody who doesn't find leafy greens tasty, then a daily green smoothie regimen is a great way to help ourselves with 2-3 servings of leafy greens in a predictable and convenient fashion.

Even if we are confident that we’re eating enough leafy greens for lunch and dinner, I’d still recommend preparing an 8oz green smoothie daily. Those extra leafy greens pulverized by a blender are worth the effort :)

Cruciferous veggies produce a compound called sulforaphane. This compound has many health benefits including cancer protection. See Cruciferous Veggies for details.

Kale and collards are cruciferous veggies that are commonly used in green smoothie recipes. In addition, we could experiment with other cruciferous veggies like broccoli, arugula, bok choy and Brussels sprouts too.

Broccoli sprouts are special! 1 cup of broccoli sprouts equals 27 cups of broccoli in terms of sulforaphane production — see Broccoli Sprouts and Daily Cruciferous Intake: How To? So we may wish to experiment with broccoli sprouts in our green smoothie, just like Dr Douglas Won's recipe above.

For tackling heart disease, Dr Esselstyn encourages us to eat leafy greens six times a day, spread across the day — see Dr Esselstyn's WFPB guidelines for heart health. So those following Dr Esselstyn's guidelines must strive to eat leafy greens with every meal! In breakfast too! How may we eat leafy greens during breakfast? By making a green smoothie :)

How do leafy greens protect our heart? Turns out that many leafy greens are nitrate rich veggies. Such veggies promote NO production inside our body which protects our endothelial layer, which in turn protects us from heart attacks. See Plant Nitrates & Nitrate Rich Veggies for details.

Beets: Nitrate rich veggies includes non-leafy greens like beets, watermelon and fennel too. So we may consider adding such veggies to our smoothie as well. Indeed, beets and watermelon are part of Dr Greger's Pre-Workout Smoothie.

Vinegar: Dr Esselstyn encourages us to eat leafy greens with some vinegar. This boosts NO production which protects our heart. For details, see Vinegar. So we may consider adding a small quantity of vinegar into our green smoothie.

Green tea, matcha, hibiscus: Green tea is cancer protective. Matcha is powdered green tea and it's one of the ingredients in Dr Kristi Funk's Antioxidant Smoothie. In addition, we may experiment with hibiscus tea (high in antioxidants) and other teas too!

"Berries are the best fruits!" — Dr Greger. Berries are antioxidant rich and packed with nutrition — see Berries for details.

Blueberries and amla powder (gooseberry powder): These two berries are commonly added to green smoothies. For their health benefits, browse through Blueberries and Gooseberries / Amla.

… we need not limit ourselves to blueberries and amla (gooseberry) powder; we may experiment with myriad other berries like strawberries, blackberries, raspberries, cranberries, and so on. See Berries for ideas.

Herbs and spices are packed with antioxidants and anti-inflammatories — see Herbs & Spices for details. Which ones go well with smoothies?

Turmeric & a pinch of black pepper: Turmeric is the best spice. It's so special that it's a food group by itself in Dr Kristi Funk's 14-component cancer protective WFPB food system. We should consume turmeric with a pinch of black pepper to boost the bioavailability of curcumin in our body. See Turmeric: How To Consume.

Other spices: Cinnamon, nutmeg, fresh mint leaves, cayenne pepper, ginger, cloves: all of these are worth experimenting with.

Fresh herbs: We should experiment with fresh herbs like mint and cilantro as well! A combination of mint, ginger, cayenne pepper and lemon will enhance the flavor of any green smoothie.

Mushrooms are rich in antioxidants and cancer protective! See Mushrooms for details. So we may consider adding some mushroom powder into our green smoothie. Om Mushrooms offers both individual mushrooms and mushroom blends — these blends may be used for smoothies, teas, broths and soups.

Are seeds healthy? Yes!

• Seeds are cancer protective — see Are Seeds Healthy? Dr Fuhrman has a 6-letter acronym: G-BOMBS which stands for (G)reens, (B)eans, (O)nions, (M)ushrooms, (B)erries and (S)eeds — all six of these are cancer protective.
• Seeds also boost micronutrient absorption: see Should Salad Dressings Be Fat Free?
• Flax seeds, chia seeds and hempseed are rich in Omega-3 fatty acids. Dr Brooke Goldner's smoothie recipes have large amounts of flax seeds and chia seeds. See Smoothie Recipes By WFPB Doctors.
• Seeds have many other health benefits. See Seeds by Dr Greger.

Flax seeds: Flax seeds are special: see Flax Seeds for numerous benefits of flax seeds. Dr Greger's Mango Blueberry Smoothie has flax seeds.

Other seeds: For green smoothies, we may experiment with not only flax seed but also chia seeds, hempseed, sunflower seeds, pumpkin seeds and sesame seeds. A few other seeds that may or may not go well with a green smoothie: cumin seeds ('jeera powder' — this may be okay in small quantities), black cumin seeds, fenugreek seeds (overnight soaked, possibly sprouted), fennel seeds, basil seeds and niger seeds. Seeds may be soaked overnight to soften them, then added to a smoothie.

Soy milk, edamame, tofu: Soy foods are health promoting and cancer protective: see Soy, Tofu, Tempeh. We can introduce soy milk, edamame or tofu into our smoothie. For example, all three of these recipes have soy milk: Dr Kristi Funk's Antioxidant Smoothie, Dr Greger's Pumpkin Pie Smoothie, and his Dr Greger's Mango Blueberry Smoothie. We may experiment with edamame or tofu too.

Dr Greger's smoothie recipes have both fruits and berries: Dr Greger's Mango Blueberry Smoothie, Dr Greger's Pre-Workout Smoothie, and Pumpkin Pie Smoothie. Is it okay to blend fruits in smoothies? Yes: Dr Greger explains in this article: Do Smoothies Cause Overly Rapid Sugar Absorption? (2017).

What else may we add to our smoothie that is not covered above? Coconut water, lemon and various rainbow-colored veggies like tomato, cucumber, zucchini, chayote, …

When we prepare a smoothie in a blender, we break apart many more cell walls than is possible via chewing alone. Is that a good thing? Yes. Below is a short summary; for details, see Should We Consume Pulverized Whole Foods?

• Leafy greens and berries: pulverization is beneficial. Why? “Leafy greens are the best veggies! Berries are the best fruits!” — Dr Greger. They are packed with micronutrients (phytonutrients, antioxidants and so on). Through mechanical blenderization, we break apart as many cell walls as possible through blenderization to make all those micronutrients available to us.
• Whole grains: rarely added to green smoothies. Pulverization of whole grains into flours or smoothies is discouraged. Why? Whole grains are starch rich. Blenderization into flours and smoothies increases glycemic index, promotes overeating and disrupts the fiber, thereby reducing food for our gut bacteria. See The Science Underlying Whole Grains Hierarchy for details.
• Fruit: Dr Greger is okay with adding some fruit to our smoothies. Dr Greger explains in this article: Do Smoothies Cause Overly Rapid Sugar Absorption? (2017).
• Tubers like potatoes & sweet potatoes: These may be an interesting additive to green smoothies even though these are starch rich.

(1) Smoothie Recipes By WFPB Doctors

(2) How To Chew Our Smoothie

(3) Flavor Combinations For Green Smoothies