Green juice: it’s the new low-fat diet. It’s the new South Beach. It’s the latest in the constantly fluctuating world of health crazes, and if it works for you, great. It’s not something I hold any major judgment against, unless it’s serving as the base of your caloric intake—if that’s the case, please eat some guacamole, like, now. With drinking fruits + veggies in such high fashion, this recent email from a certain badass babe is right on point:
I was just in the grocery store, and pulled out my phone to quick find a good green smoothie recipe I could make with a few simple ingredients to sort of level out this intense caffeine buzz I’ve got going. One of the articles I passed over while scanning was something to effect of “How Green Juice is Devastating Your Body” and I just, you know, like, what? I was hoping you would tackle the “what’s true and not true” about all these “what’s good for you” tales, and where an average girl can lay her trust.
Oof. So the Miracle Drink is bad for us, now? This feels like that time in the early 2000s, when the Atkins diet started to fall apart because people were trying to subsist on chicken nuggets (it’s protein!) and lite Cool Whip (no calories!)—seriously, I know someone who did that.
Here’s a rundown* of the arguments against + for juicing and a heavy reliance on veggies, plus some actionable strategy on eating your greens in the healthiest way possible.
The most highly controversial article I’ve found around the juicing/leafy greens debacle is a New York Times op-ed titled “Kale? Juicing? Trouble Ahead?“. The writer, recently diagnosed with hypothyroidism, questions within the piece many foods she’d previously believed to be extremely healthy. Upon receiving her diagnosis, she:
looked up the condition on the Internet and found a list of foods to avoid. Kale, which I juiced every morning, tops the list, followed by broccoli, cauliflower, cabbage, Brussels sprouts and collard greens — the cruciferous vegetables I consumed in large quantities because they are thought to prevent cancer, which runs in my family. And flax — as in the seeds — high in omega 3’s, that I sprinkled on cereal and blended in strawberry almond milk smoothies. Also forbidden: almonds and strawberries, not to mention soy, peaches, peanuts, corn, radishes, rutabaga and spinach.
Ouch. Welp, there goes most of what we health nerds buy at the grocery store each week, right? Maybe…or maybe not. C.C.N. and pre-med, post-bacc Georgetown student Gena Hamshaw (of Choosing Raw fame) responds:
Yes, it’s true that cruciferous vegetables, flax, soy, almonds, and a number of other foods are thought to be problematic for those with hypothyroidism. This is because they contain compounds called glucosinolates which, when broken down through digestion, may either interfere with thyroid hormone synthesis or compete with iodine for uptake by the thyroid gland (iodine is crucial to thyroid health). People with hypothyroidism are often cautioned to limit crucifers, but it’s worth noting that cruciferous vegetables rarely seem to be a direct cause of hypothyroidism. Extremely high intakes have been shown to cause hypothyroid symptoms in animal studies, but I read about only one reported case of this phenomenon in humans: an 88-year-old woman who developed severe hypothyroidism after eating between 1 and 1.5 kilograms of raw bok choy daily for months.** So, in spite of the fact that the author was clearly consuming a lot of raw kale, it’s hard to say if her zeal for healthy eating (embodied in kale juice) actually made her sick. Moderate cruciferous vegetable consumption isn’t a problem for people with normally functioning thyroids.
WBUR also looked into the topic and asked Teresa Fung, Sc.D., M.S., adjunct professor of nutrition at the Harvard School of Public Health and professor at Simmons College in Boston, for her take. According to Fung, “It’s the dose that makes a poison. If people have hypothyroidism or they’re taking thyroid medication, then they should check with their doctor. But even in this case, reasonable amounts shouldn’t be a problem.” And keep in mind that poison-level dosage refers to, say, a full kilogram of raw kale—daily—for months at a time.
So, what’s the takeaway from the controversy? Unless they make up the bulk of your calories, consuming cruciferous vegetables—like kale—in raw form–like green juice–is fine. If you have a family history of hypothyroidism or are on thyroid medication, check with your doctor. But even then, a serving or two a day should be okay. WBUR also asked eating coach Nina Manolson for her take on the safest ways to get your greens without going overboard; to prevent any misinterpretation from paraphrasing, her suggestions below are cited straight from this article:
1. Cook Your Kale The goitrogenic properties of kale become dramatically lessened when kale — or any other cruciferous vegetable — is cooked. (Other veggies in this category include: broccoli, brussel sprouts, cabbage, cauliflower, collard greens, kohlrabi, mustard, rutabaga, turnips, bok choy and Chinese cabbage. Arugula, horseradish, radish, wasabi and watercress are also cruciferous vegetables.)
2. Eat Seaweed Kale on its own does not increase the risk of thyroid problems. It’s a combination of factors; including potential iodine deficiency. (One of the most common causes of goiters is iodine deficiency.) Adding seaweed or another iodine rich food to your diet may, in some cases, help you get adequate iodine.
3. Throw A Brazil Nut Into Your Smoothie Selenium can support normal iodine levels which in turn may support a healthy thyroid. A Brazil nut or two in your daily smoothie or as a topping to any dish might help keep selenium levels strong.
4. Switch Up Your Greens Vary your greens. If you’re going to eat kale one day choose a non-cruciferous, non-goitrogenic veggie dish the next, like a simple cucumber and tomato salad, or beets. There are many highly nutritious vegetables that aren’t goitrogenic, including celery, parsley, zucchini, carrots and more. Our bodies need many nutrients and by eating a variety of vegetables you’ll ensure that you don’t overload on one and skip another.
How do you typically get your daily veggie dosage? Are you a smoothie addict? A salad fiend? Or you prefer roasting/steaming/baking those bad boys? (I’m a mixed bag–lunch usually consists of a massive bowl of steamed veggies + sauce, but dinner might include a raw leafy green or two.
Or it might include nothing but oatmeal and peanut butter.
We’ve all got our on and off days).
*Please know that this post is the product of research, not a medical degree. I did not go to med school, but I’m great at reading.
**Gena lists all of her research sources here.
This post originally appeared on Eat Well. Party Hard.
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