You’ve probably heard it before, and I say it often – rotate your greens!
But why? Why not just have the same two handfuls of spinach in every green smoothie you make, day in and day out? Well, there are a couple reasons.
1 – Some Greens Are More Nutritious Than Others
First of all, adding a variety of leafy greens to your diet promotes nutritional diversity. Different foods have different amounts of nutrients. By eating a variety of leafy greens, you’ll get a more balanced amount of vitamins and minerals.
Also, certain greens have unique phytonutrients that you might not get at all, or in smaller amounts, by eating only one or two types of leafy green.
It would be a shame to eat nothing but spinach when kale and dandelion have much higher levels of calcium, iron and protein. So don’t get stuck in a rut with your leafy greens. Branch out and diversify!
2 – Avoid Potential Overdose Of Anti-Nutrients
The second, and perhaps biggest, reason you should rotate your greens is that all leaves contain small amounts of toxins as a defense mechanism to protect a plant from predation. For example, goitrogens in kale and other brassicas can interfere with thyroid hormone function in susceptible individuals. Oxalic acid in spinach can be problematic for people who are prone to kidney stone formation.
Consuming a couple handfuls of spinach or kale in a green smoothie every day is perfectly safe for most healthy people who do not have a pre-existing health condition that could be aggravated by these foods. It his HIGHLY unlikely that you will experience any sort of toxicity from eating larger-than-average portions of leafy greens as part of a healthy, whole foods diet.
The problem, however, arises if you currently have a medical condition that may be exacerbated by certain compounds found in some leafy greens. Or if you go all crazy about the amount of leafy greens you eat. And by crazy, I’m talking about consuming three or more bunches of greens every single day.
I came across this case of an elderly woman who ate 2-3 large heads of bok choy every day for several months in an attempt to manage her diabetes. She ended up in the hospital with severe hypothyroidism that was attributed to the over-abundance of the myrosinase enzyme present in raw bok choy.
Wait – So Leafy Greens Can Be Harmful?
No! Raw raw bok choy is not poisonous in reasonable amounts. Putting kale in your green smoothie will not give you hypothyroidism. Spinach smoothies will not give you kidney stones.
Leafy greens are not toxic in the amounts that I use in my green smoothie recipes. I have raw baby bok choy in my green smoothies on occasion with no ill effects. I consume more kale in one week than most Americans consume in a year. My thyroid blood panel (after four years of green smoothies) came back absolutely normal (so did my husbands).
Two cups of fresh baby spinach per day probably isn’t going to lead to any problems, but one pound of spinach or three bunches of kale per day might.
Rotaing greens becomes more critical for people who follow a raw vegan diet, where the amount of leafy greens is generally higher in order to obtain sufficient calcium and iron.
How To Rotate Your Greens
My strategy to get a variety of leafy greens in my diet is to eat up to two bunches (6-8 cups) of greens per day (on average). I make sure that my intake is varied to avoid an overabundance of any particular food that could cause a nutritional imbalance or anti-nutrient toxicity.
For example, I might eat dandelion greens and romaine lettuce every day for two weeks, and then I’ll switch to beet greens and kale for a couple weeks. Then I might have leaf lettuce and spinach for a few days.
It is important to rotate greens among different plant families. Rotating one brassica-type vegetable like kale with another brassica like bok choy isn’t a good rotation because you are still getting the same anti-nutrients that are in all brassicas.
Here’s a chart that sorts leafy greens into their families. I use this chart as a guide for rotating greens.
Should You Rotate Fruit?
Now you’re probably wondering if you should be rotating fruit in your green smoothies as well. Fruit isn’t so much of a concern because potentially harmful anti-nutrients that could harm humans are usually found in the seeds (which we don’t usually eat anyway).
Fruit is supposed to be edible because that is how plants disperse their seed. You wouldn’t want to poison the ones helping you propagate, now would you? If an herbivore eats to many leaves, the plant dies. However, the eaten fruit helps plant species survive through seed dispersal.
Now, that being said, some species of edible fruits do have small amounts of toxic compounds that aren’t acutely poisonous when eaten in normal amounts, but could build up over time and cause a problem.
A good example of this are soursop and cherimoya. Both contain annonacin which some studies suggest may lead to brain lesions in populations with high consumption of these fruits. Of course, there are also wild fruits and berries that are highly toxic to humans.
So the big takeaway here is that a varied diet consisting of a regularly rotating mix of different plant-based foods should not pose a health problem, but excessive eating of one particular fruit or vegetable over a period of time could lead to nutritional imbalances and in some cases, toxicity.
So don’t get stuck in a rut. Branch out and explore ALL areas of your store’s produce section!
Need ideas? Browse hundreds of green smoothie recipes in any flavor you can think of!
Tracy Russell is the creator of the Green Smoothie Weight Loss Program, the 30-Day Whole Foods Challenge and founder of Incredible Smoothies. She is passionate about helping people improve their health with green smoothies and a whole foods lifestyle.