Calcium in Selected Plant Foods

I noticed that the new USDA nutrient database seemed to have changed the amounts of calcium in some of the greens they had listed. I have updated Table 5 in Bones, Vitamin D, and Calcium at

The USDA database lists a number of different versions for foods – for each type of greens, for example, there are a half dozen to a dozen entries. In the past, I’ve tried to take the most usual or average them out. This time, in updating Table 5, I used the exact entry and I included a number of entries for some of the foods.

Unfortunately, the amount of calcium in broccoli was lowered from 50 to 31 mg per serving. Other greens seemed to stay about the same.

11 Responses to “Calcium in Selected Plant Foods”

  1. Zak Says:

    Hi Jack –

    I just reviewed the chart. Any idea why collards that have been frozen then cooked would have higher calcium than fresh and cooked?

  2. Jack Norris RD Says:


    Much of it can be explained by being more dense, as the frozen also has more calories (31 kcal for frozen vs. 25 kcal for not frozen). But that doesn’t fully explain the difference and I don’t know what would account for the rest of the difference.

  3. Dan Says:

    Hi Jack,
    About the amount of calcium in plants: doesn’t it depend from the amount of calcium found in the soil where it grows? In other words, can you have huge differences of calcium value for the same plant depending on how it’s grown? Or is there little incidence?

  4. Jack Norris RD Says:


    I don’t know.

  5. Ben Says:

    Dear Jack,

    One of my favorite vegetables is Butternut squash. I eat (almost) every day. Something like 1lbs to 3lbs a day.

    I have noticed that it has a decent amount of calcium. I know, as well, that it’s considered a low-oxalate vegetable.

    But as it’s not a leafy one, I wonder if I might count it as a major source of calcium, or not? (I asked myself the same question with lettuce. It seems only cruciferous green leafy vegetables are listed as a reliable source).


  6. Jack Norris RD Says:


    Butternut squash has 42 grams per 1/2 Cup cooked. That’s probably not enough to be included as a major source. I have foods in my Table that aren’t much better (or not even as good), but they are there because people tend to think of them as good sources of calcium and I want people to see how much they actually have. But if I had to add every source as good as butternut squash, the list would be quite long.


  7. Ben Says:

    OK, thanks, I knew that already, but as I had mentioned, I regularly eat at least 1lbs (and usually more) of Butternut squash a day. So I wonder if the calcium in it is highly absorbable, or should I count only the calcium coming from greens?

  8. Jack Norris RD Says:

    If it’s low in oxalates and phytates, and I don’t see why it wouldn’t be though I don’t know for certain, then I think it’s safe to assume it is counting towards your calcium intake just as much as any other food. I’d be a bit more hesitant if it’s raw than if cooked.

  9. Konstantinos Says:

    Ηι Jack,

    I would like to ask why in the vegan food guide of your book, you consider as 1 serving of calcium rich food, 1/2 cup cooked or 1 cup raw leafy vegetables which is different from the vegetarian food guide pyramid which consider as 1 serving 1 cup cooked or 2 cup raw leafy vegetables.

    Why is this difference. Shouldn’t I rely on the pyramid?

    Thank you!

  10. Jack Norris RD Says:


    I don’t know what vegetarian food guide pyramid you’re referring to, but Ginny and I used the serving sizes that we believed to be most commonly used for the various foods. I would rely on our guide to make sure that you’re getting enough calcium. You can also see our food guide here:

  11. Konstantinos Says:

    Hi Jack,

    I am referring to the food pyramid from this paper :

    As you can see from the vegetarian food guide pyramid 1 serving of calcium rich food is 1 cup cooked or 2 cup raw leafy vegetable, which is different from the guide ofyour book (1 serving of calcium rich food is 1/2 cup cooked or 1 cup raw leafy vegetables).

    Thank you!

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