I was taking a break from trying to figure out what to blog about and reading my twitter feed when I was inspired by a tweet: “Fun stat: Kale has more iron in it than beef and Kale chips are YUM. Also a good source of protein,calcium,and fibre. More calcium than milk”. Was this tweeted by someone with any sort of nutrition background. Nope. I love that the Internet gives everyone a voice. Unfortunately, that’s also the downfall of the Internet. Misinformation is easily spread with the click of a button. What’s wrong with this tweet in particular? It’s not that kale isn’t great. Kale is awesome and probably the most nutritious of all the leafy greens. The problem is that the facts provided in this tweet are misleading. Let’s look at a comparison of the iron in kale and beef: one serving of kale (1/2 cup cooked) contains 0.62 mg of iron, one serving of beef (75 g cooked steak) contains 2.06 mg of iron. You don’t have to be a math whiz to figure out that the beef clearly has considerably more iron than the kale. It’s also important to bear in mind that the form of iron in meat (i.e. heme iron) is more easily absorbed than the non-heme iron found in plants. That means that you’ll absorb a greater percentage of the iron in the beef than you will of the iron in the kale (or any other plant-based source of iron). Now what about the other nutrient claims in this tweet… Is kale a good source of protein? 1.3 g. Not too bad, also important to keep in mind that it’s not a complete protein, it doesn’t contain all of the essential amino acids. That means that you need to include other sources of protein to get all of the amino acids your body needs. Is kale a good source of calcium? 49 mg. Not too shabby, right? Well, the recommended daily intake of calcium for adults between 19-50 years of age is 1, 000 mg so you still need a LOT more sources of calcium in your diet. Is it more calcium than milk? One cup of milk has 316 mg of calcium. Even if we go measure for measure, milk has way more calcium in it than kale does. How about fibre then? 1.4 g. That’s okay. At the lowest end of fibre recommendations it’s about 6% of what an adult should be getting in a day.
I don’t want to come across all down on kale. I truly love kale and I think it’s a great food. I just don’t want people to read one misinformed tweet and think that kale is a magic food providing them with practically all of the nutrients they need. As I’ve said before; there are NO super foods! You need to consume a variety of foods to obtain all of the nutrients that your body needs to function at its best.