Science Facts Sundays: Maximizing Iron Absorbency, Part 6: Vegetables

Welcome to Science Facts Sundays.

These are some notes I took when reading Iron Rich Foods: Unlock the Iron in Your Food and Fight Iron Deficiency by Amanda Rose, Ph.D.

My daughter knows why we don’t drink milk with an iron-rich meal. She can tell you, “calcium inhibits iron absorption!”

I don’t see the point of eating foods and not being able to absorb them and utilize all their benefits. What a shame to waste the iron in our foods when we eat them with dairy products. Simply knowing to separate the foods for ultimate utilization can be helpful for combating low iron levels.

You may find this geeky – so be forewarned! If this topic doesn’t appeal to you, check back in a few weeks and I’ll have moved on to something else that you may be interested in.

Here are some morsels for you to chew on (written in my own words):

Although spinach has the reputation for containing lots of iron, it’s weak when compared to vegetables such as morel mushrooms, lemon grass, baked potatoes, and parsley. Where 100 grams of spinach contains 20% of your daily recommendation for iron, 100 grams of morel mushrooms contain a whopping 68%.

A really great way to enhance iron absorption is to consume iron-rich foods with Vitamin C.

Keep in mind that the highest Vitamin C content in vegetables is found when they are ripe. Once over-ripe, it will lose its Vitamin C content.

Fermenting Vitamin C-containing vegetables, like sauerkraut, can help maintain Vitamin C levels in the cabbage.

Like phytic acid is to grains, oxalic acid is to vegetables – an iron inhibitor.

Oxalic acid is the primary component of kidney stones. So if you are prone to kidney stones, you will want to be really careful to avoid foods high in oxalic acid.

Oxalic acid, like how phytic acid acts, can not only inhibit iron, but can also decrease absorption of other minerals.

Some of the vegetables highest in oxalic acid are: beets, brussel sprouts, carrots, collard greens, parsley, spinach, sweet potato, swiss chard, and rhubarb. These are the vegetables you want to avoid consuming raw, such as for juicing.

If you have oxalate sensitivities, you will want to further note that while we generally like to steam our veggies to retain nutrients, boiling vegetables high in oxalic acid is usually best. Where 87% of oxalic acid is reduced in spinach when boiled, only 42% is reduced when steamed. Swiss chard resulted in similar numbers. I will note, however, that although boiled carrots’ oxalic acid was reduced by 56%, steaming them reduced them only by three additional percentage points.

Another method of increasing iron in your vegetables without cooking them is to ferment them. Researchers have found soluble iron increased 16X in homemade vegetable juice when fermented. Read more here: Fermentation, Oxalic Acid, and Mineral Absorption.

That’s it for today! I hope you learned something. If you did, feel free to leave me a note in the comments :) If you didn’t learn anything, then you are definitely a geek! :D

Next week we continue the discussion on fruit and iron and phytic acid…

Amanda Rose, Ph.D. authored Iron Rich Foods: Unlock the Iron in Your Food and Fight Iron Deficiency, where I have based these science facts. She is also the author of Rebuild From Depression: A Nutrient Guide, Including Depression in Pregnancy and Postpartum, and the Phytic Acid White Paper: Reducing Phytic Acid in Your Food. She is also the blogger behind

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Lea Harris founded Nourishing Treasures in 2006. A mom passionate about her family's health and well-being, Lea believes education is power. Encouraging others to take baby steps in the right direction of health for their families, Lea's goal is to raise awareness of what goes into our mouths and on our bodies, providing natural alternative information that promotes health and prevents disease by using traditional foods and nature's medicine.

Lea is a Certified Health Coach graduate from Beyond Organic University, and a Certified Aromatherapist graduate from Aromahead Institute.

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Science Facts Sundays: Maximizing Iron Absorbency, Part 6: Vegetables — 6 Comments

  1. wow! that’s diffidently a revelation to me! in fact its super timely!… and I just last night was wondering why my usual juice of carrots and spinach is actually doesn’t make me feel better at all( it fact there’s this unpeasant aftertaste:(( and I usually lightly satee broccoli and spinachi with some butter and curry paste…and if I undercook it it gives the same unpleasant aftertaste:( oh…so no more carrot juice?!!!!! i lv it
    thank you for great post and education morsel:)))

    • Alex — Lea and I are part of the demographic that gets concerned about iron deficiency, you are more likely to have a problem with iron overload than we are. One of the best ways to avoid it if you’re otherwise healthy is to be a regular blood donor. (Talk to your doctor.) A non-meat diet would help. Some meat-eaters actually take a phytic acid supplement.

  2. so do you never drink straihht carrot joice with greens now? I was thinking..what about traditional dishes using fresh spinah leaves? like spanokopita? it uses spinach and cheese…maybe dairy reduces oxalic acid availablity for digestion? or indian dishes..they use plenty of green leafy plants…

    • It depends on the greens. Kale would be a better choice than spinach for raw greens. And if you aren’t sensitive to being deficient, you can probably enjoy them without harm. If you are one who borders on anemia, you will want to skip the raw carrot juice.

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