Soaking grains might help you absorb more nutrients but is it really worth the trouble?
Soaking grains might help you absorb more nutrients but is it really worth the trouble?
Nutrition Diva is hosted by Monica Reinagel. A transcript is available at Simplecast.
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Hi Monica, this is Christina. I was wondering about the benefits of soaking grains before you use them. I have heard people go so far as to say that you shouldn’t use grains without soaking them because you don’t get the full benefit. I’m wondering whether I need to go to all that trouble?
I’m guessing that many of you listening are staring at your iPods or computers with big cartoon question marks over your heads right about now. This might be the first you’ve ever heard about the hazards of eating unsoaked grains. But I’ve actually gotten questions about this from several listeners. So, let’s dive in.
First, a bit of background: The so-called “cereal grains” (wheat, corn, barley, rice, and oats) all contain a natural compound called phytic acid. Dried beans, nuts, and seeds also contain phytic acid. Let's pause for a moment to look at a chart showing you the phytic acid content of some common foods. You’ll see that, as a rule, beans and nuts are higher in phytic acid than cereal grains.
| Food | Percent phytic acid (by dry weight) |
| Polished rice | 0.14 -0.6 |
| Whole wheat bread | 0.43 - 1.05 |
| Barley | 0.38 - 1.16 |
| Oat | 0.42 -1.16 |
| Wheat flour | 0.25 - 1.37 |
| Wheat | 0.39 - 1.35 |
| Rye | 0.54 - 1.46 |
| Oat bran | 0.6 - 1.42 |
| Kidney beans | 0.89 - 1.57 |
| Peanuts | 1.05 - 1.76 |
| Corn | 0.75 - 2.22 |
| Soybeans | 1.0 - 2.22 |
| Oat Meal | 0.78 - 2.4 |
| Soy flour | 1.24 - 2.25 |
| Tofu | 1.46 - 2.9 |
| Linseed | 2.15 - 2.78 |
Source: REDDY, N. R. and SATHE, S. K. (2002). Food Phytates. Boca Raton, CRC Press.
In all cases, the phytic acid is concentrated in the hull or bran. If you remove the hull, you remove most of the phytic acid, too. White rice, for example, is much lower in phytic acid than brown rice.
Phytic acid is sometimes referred to as an “anti-nutrient.” Doesn’t that sound sinister? They call it that because it has a tendency to bind to certain minerals and block their absorption in the small intestine. If you eat foods containing phytic acid, you’ll get much less calcium, iron, copper, and zinc from the foods that you eat at the same meal than you would if there were no phytic acid present.
And this is why some people say you should soak grains and nuts before eating them. Soaking these foods in water for 12 to 24 hours will eliminate much of the phytic acid and increase the bioavailability of the minerals they contain.
But, as Christina asks, do we really need to go to all that trouble?
Well, first of all, grains are probably not your primary source for calcium, iron, and zinc anyway. Dairy products contain lots of calcium and no phytic acid. Meat and seafood are good sources of bioavailable iron and zinc. Vegans, I haven’t forgotten you! Iron and calcium are found in vegetables like kale, broccoli, cabbage, and bok choy. Lots of foods—vegan and otherwise—are also fortified with iron and calcium.
The truth is that mineral deficiencies caused by too much phytic acid in the diet are mostly a concern in developing countries where diets tend to be nutritionally deficient or borderline. Ironically, the other situation where it might be a concern is at the other end of the spectrum: health-conscious people who eat very large amounts of beans, nuts, and unprocessed grains at every singe meal—especially if they also avoid meat or dairy products.
Because my diet is not at either extreme, I don’t worry too much about phytic acid myself. But, hey, everyone needs a hobby! If you’d like to make reducing phytic acid yours, here are several ways to do it.
Soaking or Cooking. As I said earlier, soaking foods for 12 to 24 hours can reduce phytic acid content. However, keep in mind that soaking foods in water also leaches out many of the minerals that you’re trying to preserve. And it doesn’t make much sense to soak rolled oats, rice, or other grains if you’re going to cook them afterward because the phytic acid will be reduced during the cooking process anyway.
If you eat uncooked rolled oats for breakfast, you can soak them in water overnight to reduce the phytic acid content. Soaking them in yogurt or buttermilk works even better. Acidic liquids are more effective in reducing phytic acid. Plus, yogurt and buttermilk are fermented with friendly bacteria that help break down the phytic acid enzymatically.
Sprouting. Many whole grains and dried beans, like wheat, barley, kidney beans, and chickpeas can be sprouted in jars on your kitchen windowsill. Not only does this reduce the phytic acid content but it softens them up so you can eat them without boiling them—preserving even more valuable nutrients. Many people enjoy adding sprouted grains, seeds, and beans to salads, powerhouse sandwiches, and stir-fries. I’ll include a link to more information about how to sprout in the show notes.
Fermenting. Finally, fermenting foods with lactobacillus bacteria is a very effective way to reduce phytic acid content. Tofu, for example, is pretty high in phytic acid. But tempeh and miso, which are made from fermented soybeans, are low in phytic acid.
You can find tempeh in health food stores or grocery stores with a good-sized “natural foods” department. I’ve never attempted fermenting soybeans at home, myself. But if you want to make this new hobby of yours a little more interesting, I’ll include a link to information on making your own.
If you need advice on getting better results with whole grain baking, I have a handy little Quick Tip just for you. And click here for a tip to boost the nutritional value of your grains.
Keep in touch! I love hearing from you. Post your comments and questions on my Nutrition Diva Facebook page, hit me up on Twitter, or send an email to nutrition@quickanddirtytips.com.
Have a great day and eat something good for me!