Am I eating too many greens?

April 25, 2023 2:16 PM

I have realized that most of my veggie intake is leafy greens. (Spinach, kale and boxed spring mix are my usual staples, but I will also cook with chard or bok choy pretty frequently.) I probably eat about 3-5 standard servings of greens on a normal day plus 2-3 servings of fruit and other veggies. I’ve read that you can eat too much spinach or kale, does this sound like too many greens or too many compared to other vegetables?

For example, today I had a fruit smoothie with raw spinach for breakfast, hummus and pita with a huge spring mix salad for lunch, and will be making a tempeh, kale and bell pepper stir fry for dinner. That’s a pretty normal day for me and probably adds up to 5 servings of greens. I’m just wondering if I’m setting myself up for any health problems by eating this way. I do like other vegetables — I’ll actually eat any vegetable — but I am somewhat lazy and love the convenience of the pre-washed spinach and salad mixes.

posted by vanitas to Health & Fitness (11 answers total)

Best answer: If your bloodwork is in a healthy range (liver enzymes, electrolytes, etc) and you're pooping ok (e.g. not bloated or shitting uncontrollably), you are fine.
posted by phunniemee at 2:25 PM on April 25, 2023 [2 favorites]

I believe the concern about spinach specifically is related to people who have kidney stones, which can be formed by calcium oxalate, and spinach has a lot of oxalates. This page from University of Wisconsin says, though,

In some people who form calcium oxalate stones, if there's no other reason (there usually are other reasons!) for that stone formation, then it might be time to try to reduce oxalate intake. After making sure calcium intake is appropriate, then a lower intake of a couple of the most oxalate-rich foods might be recommended. But here's the caveat, said Penniston:

"The foods that are highest in oxalate are also high in fiber, magnesium, potassium, and phytate. These are actually stone inhibitors. Moreover, studies show that when you reduce oxalate, you reduce your fiber intake. That can lead to constipation and other bowel issues. In general, we're trying to help people eat a healthy, balanced diet."

But this could be the source of the concern you've heard around greens?
posted by bluedaisy at 2:34 PM on April 25, 2023 [3 favorites]

I've also heard of limiting leafy greens if you're on a blood thinner. This sounds like a delicious amount of greens if you don't have a particular health concern.
posted by momus_window at 3:04 PM on April 25, 2023

The traditional advice when someone is on warfarin specifically was to limit leafy greens and other foods high in vitamin K. Warfarin is specifically a vitamin K antagonist; most other blood thinners don’t work that way and don’t have that restriction. However, the current advice is just to be consistent about eating those foods, not to limit them - after all, those are very nutritious foods! Though I suppose it’s possible someone could be such an avid greens eater their warfarin could be hard to dose and they could be asked to cut back.
posted by obfuscation at 4:42 PM on April 25, 2023 [3 favorites]

Response by poster: It was the oxalates and the Vit K that I’d heard about. What wasn’t clear to me from anything I could find is how much the limit actually is.

I don’t have kidney stones, digestive issues and I don’t take blood thinners — I just eat this way in part because it’s supposed to be healthy and I don’t want that to be counterproductive!
posted by vanitas at 5:04 PM on April 25, 2023

I too ate a lot of spinach when I begin to have a healthier diet. I developed kidney stones after a couple of years of lots and lots of spinach. I have never had kidney stones before. I get regular blood/urine test and never had any worrisome readings. They told me to drop the spinach (any dark green leafy veg) and black tea. I have done so and have not had a return of the stones so I will continue to eat a wider variety of other veg. I can still eat broccoli and Brussels sprouts so that is good.
posted by agatha_magatha at 5:47 PM on April 25, 2023

Kidney stones run in my family. Apparently one strategy is to have a lot lemon juice in your tea if you are a black tea drinker (acid defeats calcium) and if you eat greens or beets, blanch and drain them first (much of the oxalates are removed by blanching and draining.)
posted by blnkfrnk at 8:18 PM on April 25, 2023 [1 favorite]

Kale is fine with respect to oxalates, as are other cabbage-family greens such as cabbage and the leaves of broccoli. Vitamin K is generally a concern only for those taking blood thinners.

My family member with a history of calcium oxalate kidney stones avoids only spinach, beet greens, Malabar spinach, rhubarb, and sorrel. Drinking cow's milk (well, any animal milk) helps bind oxalates from food, so when I'm being truly excessive with consuming beets I just drink a glass of milk with them; note that I have never had a kidney stone and am just being prudent.
posted by metonym at 10:34 PM on April 25, 2023 [1 favorite]

Yes, current guidance about blood thinners is to be consistent about how many leafy greens you eat. Even if someone doesn't adhere to this advice, though, it just means more frequent INR checks and possible dose changes. If you aren't on blood thinners and don't tend to make oxalate stones, I think you're fine.
posted by altolinguistic at 12:51 AM on April 26, 2023

Large quantities of raw kale can cause problems (it can block iodine absorption, and there's something else too I can't find now). Cooked kale is generally fine.
posted by BinaryApe at 12:54 AM on April 26, 2023

Best answer: For example, today I had a fruit smoothie with raw spinach for breakfast, hummus and pita with a huge spring mix salad for lunch, and will be making a tempeh, kale and bell pepper stir fry for dinner. That’s a pretty normal day for me and probably adds up to 5 servings of greens.

Honestly, if this is your typical diet, I think if you mentioned this to your doctor they'd probably hug you in gratitude.

Unless the fruit smoothie you're making is like a two-gallon serving or the spring-mix salad is in a bowl the size of a child's sandbox, you're fine.
posted by EmpressCallipygos at 2:02 PM on April 26, 2023 [1 favorite]