Spinach: Raw vs. Cooked Pros and Cons

spinach leavesWhen I was a child, the only spinach anyone ate was cooked, or put more accurately, OVER cooked and sometimes pureed with a bit of cream in it to make up for the blah taste.

Only it didn’t work for me as a toddler.

I recall very clearly when I must have been 4 years old or so, vehemently and tearfully refusing to eat the spinach and egg that my well intentioned mother insisted I eat.  Imagine egg yolk spilling into the overcooked spinach juices.  Eeew.

Back in those days, there was no negotiating so of course I was forced to eat it…or else.  That ‘or else’ was most likely nothing else to eat.  I am sure my mother won but gave up on that meal plan for future.

Years later as an older child, I rediscovered spinach…and loved it.  No egg, of course.  It came in a tin back then, was dark grey-green and I’d eat it straight from the tin when no one was home to stop me.  Sometimes with a splash of vinegar.

Even more light years ahead into the trendy 90’s and early millenium years, raw spinach salad was THE healthy trend in restaurants and for home…smugly touted as the only way to eat it.

But is it…healthier?  Well, yes and no.  It’s the oxalic acid content that can be problematic.

Oxalic Acid – What is it and why it can be a problem – for some people.

Oxalic acid is an alkaloid found in many foods such as seeds, grains, some fruit and vegetables.  Its role, for the plant, is to protect it from foragers.  Eating too much of high oxalic content plant matter will eventually provoke a ‘time to move on’ response, thus protecting the plant from extinction via serious animal munchies.

It is quite similar for humans, only we tend to ignore the signals our body tells us.  Those who down glasses of raw kale and other greens in smoothies, invariably feel a growing aversion – the need to take a break.  This is often ignored because it’s become part of the daily routine and is supposed to be ‘good for me’.

Except that for some people with a tendency toward kidney stones, it is not…at least not in high quantities and daily.

The Problem – the Cons

Oxalic acid binds with calcium (and other vital nutrients) rendering them rather useless to the body.  This includes not only the calcium in spinach but the cheese or legumes you may be serving it with.  This ‘binding’ forms crystals of calcium oxalate, which will eventually form kidney stones in those individuals with said tendency.  Solution:  avoid too much and too frequent consumption of oxalic acid containing foods.  Logical.

The Pros

In the case of raw spinach,  if you have no known tendency to kidney stones, there is no need to avoid it because of the oxalic acid. Spinach is rich in many essential nutrients such as folate, vitamin C (enhances iron absorption), niacin, riboflavin, and potassium.  These are more available when consumed raw.

Wilting, blanching or cooking spinach on the other hand increases the bio-availability of vitamins A and E, protein, fiber, zinc, thiamine, calcium, and iron as well as the carotenoids, such as beta-carotene, lutein, and zeaxanthin and it reduces the oxalate content somewhat (between 5 to 15%).

Iron in both forms, either raw or ‘cooked’ is not affected as long as the vitamin C which facilitates the absorption of iron has not been destroyed through over cooking.  When in doubt, serve it with lemon juice or orange sections or even apple cider vinegar.

Why do some people have a tendency towards kidney stones and should avoid oxalate acid?  Here is an excellent article on the role of  Oxalic Acid, Calcium Misplacement and Kidney Stones .

So, are you still worried?  Don’t be.  Just don’t overdo it with spinach or other oxalate rich foods and eat both raw and cooked forms to take advantage of the nutrients available with either method.

Today I am no longer on the fence about the best way to eat spinach.  I love it any way I get it.  Even with eggs!



Selected resources:

  • http://www.ncbi.nlm.nih.gov/m/pubmed/23791752/?i=22&from=raw%20spinach
  • http://www.whfoods.com/genpage.php?tname=george&dbid=48
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