You hear “spinach”, you probably think about Popeye and iron. We all know that spinach is an amazing supergreen that boasts ten times the iron content of any other vegetable, right? Wrong!
Back the 1870s, a scientist named Dr. E von Wolf was studying the content of various foods, and published his work with a tiny little mistake that lead to sixty years’ worth of “oops”. There’s some debate on what really happened, but either he mixed up dried and fresh in his reporting or he had his decimal point in the wrong place. Either way, he wound up giving spinach ten times the iron content it truly has. The error gave spinach about as much iron as red meat, so it became a valued substitution given how much cheaper it is.
This little error blew up to major proportions when Popeye came on the scene in the late 1920’s. Throwing spinach down his throat lead to huge muscles popping out; ostensibly due to them muscle-building iron it contains. It’s really too bad we don’t have any vegetables sponsored by cartoons today (although I did see Shrek-sponsored onions once when one of the movies was new). Due to Popeye, spinach consumption increased by about 33%, with kids eagerly emulating their muscular hero.
The error was discovered in the 1930s, and Popeye defenders are quick to point out that it was really the vitamin A in spinach that lead to his strength. According to Mike Sutton, who has done a vast amount of research into this whole debacle, Popeye never mentioned eating spinach for the iron. That concept must have come from the public.
The Truth is Revealed (Slowly)
It was in 1937 that spinach’s iron status returned to its rightful place amongst the rest of the green veggies. Scientists realized then it only had 10% of what von Wolf had stated, meaning it had less iron than tomatoes and oranges, and that it only had about the same as plain old lettuce.
Then, in the 1990s, research into bioavailability and absorption found that due to some other compounds in the spinach, only about 2-5% of the iron that IS in the spinach is able to be absorbed. Put those decimals together and we now know it has only 0.2-0.5% as much iron as our grandparents in the 1930s thought it had. At one point, iron was thought to be equal to red meat in terms of iron content, and we now know it effectively has almost none.
But Wait! Don’t Hang Up!
Okay, so spinach isn’t really worth much in the iron department. However, consuming it with foods rich in vitamin C, such as tomatoes or oranges, does help to increase the absorption. Conveniently, as I’ve already pointed out, those happen to be higher in iron than spinach anyway.
Even if iron had never been a consideration, spinach is still an incredibly healthy food. Just be careful when you’re reading health claims, since they’re often unclear about if the spinach is raw or cooked. If you’ve ever seen how a huge pot of fresh spinach cooks down into a puny pile, you’ll recognize the vast difference between a cup of spinach leaves in a salad and a cup of cooked spinach in lasagna. Looking at the values for cooked is far more impressive…
One cup of cooked spinach has almost 20% of your daily fiber needs, which means it will fill you up and help control your appetite. It also has five grams of protein, further slowing your digestion and keeping you full.
A cup of cooked spinach will provide about one-fourth of your daily potassium needs, which (as I discussed in my previous), is needed to balance out sodium in your body to allow for proper fluid balance in and around the cells, and for proper muscle and nerve function.
Plant foods that are deeply colored contain a great deal of beta carotene, and spinach is no exception. Beta carotene is a powerful antioxidant, offering protective benefits against all kinds of cancers.
A cup of cooked spinach provides almost four times the amount of vitamin A you need in a day, which helps keep your skin young, supple, and acne-free. Vitamin A is also important to eye function. But spinach provides even MORE eye protection; the antioxidants lutein and zeaxanthin stave off macular degeneration and cataracts.
That same cup of cooked spinach has TEN times the vitamin K you need in a day, which helps protect your bones, protects against atherosclerosis and cardiovascular disease, and enhances brain and nerve function.
With all that going on, who cares about iron?
Tomato Florentine Soup
Raw spinach still has all those benefits, but obviously in much lower quantities given the same volume, because raw spinach is mostly water. I’m not a huge fan of raw spinach, it makes my teeth feel funny. Since I usually cook my spinach, I don’t bother with fresh too often. It cooks down to nothing, and is either expensive (prewashed and bagged) or requires a ton of trimming and cleaning (bunched). A nice cheap compact brick of frozen spinach therefore seems like the ultimate in convenience and economy.
This recipe combines the best of spinach. It’s cooked down so you get a nice concentrated dose of all the vitamins and antioxidants. It’s combined with tomatoes so you get to absorb some more of the locked-up iron content. It’s awesome in the summer with fresh basil, tomatoes, and spinach (hey, if it comes from my own garden I’m willing to make an exception to my frozen-is-better notion). It’s awesome in the winter when you need something cozy and comforting, and can easily be turned “hearty” by throwing in some pasta and serving it up along with some crusty bread.
It’s simple and really lets the spinach shine. Enjoy!
- 2 tbsp butter
- 1 large yellow onion, diced
- 2 cloves garlic, minced
- 1 (28-oz) can tomato puree
- 2 cups fresh spinach, chopped OR 1 package frozen spinach, thawed and squeezed
- 1 1/2 cups milk, half-and-half, or some combination
- 1/4 cup fresh basil, chopped OR 1 tbsp dried basil
- salt and pepper to taste
- Parmesan cheese for serving, optional
Melt butter in a large saucepan over medium heat. Saute onion and garlic for about three minutes, until softened. Add tomatoes, spinach, milk, basil, salt and pepper, and simmer uncovered until heated through and spinach is tender. Serve topped with Parmesan cheese if desired.
Geeky Post Script
I can’t help but think about Wonders of the Universe when I think about iron. In that show, the poetic physicist Brian Cox tells us that all the elements on earth (and in the whole universe) come from dying stars. Stars burn by fusing hydrogen into helium. When the hydrogen is all used up, it begins to fuse the helium into lithium, then beryllium, eventually making oxygen, carbon, and all the elements up to iron. Iron fusion is the last stage in a star’s life. Then, the star either quietly disperses into a nebula or blows up into a supernova, thereby spewing all those elements across the universe, until they begin to clump together and form new solar systems. It’s kind of mind-boggling to think that the iron in your spinach, whether or not there’s a great deal of it, was once a part of a distant star that died billions of years ago.