Ask the Diet Doctor: Should I Soak Nuts, Seeds, and Grains?
The answer may help you absorb more nutrients from snacks and meals
Q: Do I need to soak nuts, seeds, and grains before eating them to remove anti-nutrients?
A: Soaking these foods in water for 12 is 24 hours is a common strategy to reduce their phytic acid content. Phytic acid is often pitched as a nutrition boogey man of sorts, preventing the absorption of key nutrients with growth-stunting consequences in third-world countries. What is interesting about phytic acid is that despite its "anti-nutrient" properties, the only thing it might be is a nutrition boogey man after all. Let's explore...
Phytic acid is how certain grains "store" phosphorus and can make up as much as 7 percent of the dry weight of seeds and cereal grains. We can't digest phytic acid because our bodies lack the necessary enzymes to break it down, and when it enters our digestive system, it can potentially cause problems.
The acid has the strongest affinity to multivalent metal ions (high school chemistry flashback alert!). In layman's terms, that means it likes to bind to essential minerals such as calcium, zinc, iron, and magnesium, forming an insoluble compound that is poorly absorbed by your GI tract. Hence, deficiencies in these essential minerals could happen.
However, nuts, seeds, and cereal grains are not the only sources of these nutrients, and most often they aren't even a key contributor in your diet. The major sources of iron, calcium, magnesium, and zinc for most Americans are:
Iron: Red meat, seafood, nuts, dark green vegetables
Calcium: Dairy, dark green vegetables, beans
Magnesium: Spinach, nuts, and seeds (I recommend supplementing with extra magnesium anyway)
Zinc: Seafood (shellfish), meat, nuts
If you follow a diet that restricts some of the above food groups, such as a vegetarian or vegan diet, or you live in an area where getting in the bare minimum of essential nutrients is the major focus of your diet, then soaking your nuts, seeds, and cereal grains is probably warranted in order to free the essential minerals from the indigestible grips of phytic acid.
Otherwise, I'd skip the soaking. It is an unnecessary extra step and despite all the bad PR phytic acid gets, it has some potential health benefits. Research in animals shows that phytic acid can decrease risk factors for heart disease such as cholesterol and triglyceride levels. Its ability to bind with iron may be a benefit, as iron is a pro-oxidant and excessive levels can have negative effects on your health. Preliminary research also shows that it can stop growth of certain breast cancers.