Phytic Acid in Nuts: Which Nuts Are Highest, and Does Soaking Help?

If you've paid nearly $20 for a bag of sprouted cashews from Erewhon, soaked and dehydrated your nuts overnight, or felt heavy after a handful of almonds, phytic acid is the reason. It's the compound behind the whole nut-soaking movement, and the one Dr. Michael Lange has in mind when he says nuts are not all created equal.

Making nuts and seeds more easy on digestion is either expensive, time consuming and potentially ineffective. But some nuts are naturally lower in this 'anti-nutrient' compound. Here's which nuts carry the most phytic acid, what it does in your body, and the simpler fix.

Quick Answer: Almonds are the highest in phytic acid of the common nuts, followed by peanuts, walnuts and cashews. Pistachios and macadamias are much lower in phytates than other nuts. Macadamia nuts are the lowest in phytic acid, with less than half the phytic acid of almonds in a study comparing 10 nuts with the same lab method. Soaking or "activating" nuts barely changes phytic acid: a 2020 University of Otago study measured changes of just -12% to +10%. Choosing a naturally low-phytate nut works better than soaking a high one.

What is phytic acid?

Phytic acid (also called phytate) is how plants store phosphorus in their seeds. It's found in nuts, seeds, grains and legumes, and it's why nutrition writers call it the "mineral thief."

In your gut, phytic acid binds to minerals, especially iron, zinc and, to a lesser extent, calcium and magnesium. Once bound, those minerals can't be absorbed. They pass straight through. So a nut can look rich in minerals on the label while delivering much less of them to your body.

Phytic acid in nuts: the ranking

The figures in our chart below come from a 2010 review, published in Public Health Nutrition, which pulled together phytic acid measurements for nuts and seeds from multiple published studies. Where studies disagreed, the review gave a range, and our chart shows the approximate average of each range. The table below that uses a different source. Its numbers are lower overall because phytic acid varies with variety, growing conditions and testing method. But both sources agree on what matters: almonds sit at the top highest nut in phytic acid, and macadamias come out lowest.

The table below uses data from a study by Venkatachalam and Sathe at Florida State University, researching the chemical composition of selected edible nut seeds in the Journal of Agricultural and Food Chemistry, quantifying constituents including phytate. It's one of the few studies that measured all the common nuts in the same lab with the same method, which makes it the fairest head-to-head comparison. 

Values are "as eaten" (not dry weight). Per-ounce figures are calculated.

Why almonds top the list

Almonds are the nut most people eat as their "healthy" default, and they're also the most concentrated source of phytic acid among common nuts. Like oxalates, this adds up through almond products: almond flour, almond butter and almond-based bars all carry the same phytic acid per gram as the whole nut. Grinding doesn't remove it.

This is also why almonds show up near the top of our worst nuts for digestion list and our oxalates ranking. High phytic acid and high oxalate in the same nut is a double hit on mineral absorption.

Is phytic acid bad for you?

It depends on how much you eat, and what else you eat.

When it matters:

• Iron and zinc. Phytic acid is one of the strongest known blockers of iron and zinc absorption from a meal. People with low iron, women with heavy periods, vegetarians and vegans, and anyone eating a lot of nuts, grains and legumes are most affected.
• High-phytate diets. Someone snacking on almonds, baking with almond flour and eating oats and legumes daily can be absorbing noticeably less of the minerals on their plate.
• Sensitive digestion. Phytic acid is one of several anti-nutrients people point to when nuts leave them feeling heavy or bloated.

When it matters less:

• Mixed diets with meat and fish. The iron in animal foods (heme iron) is far less affected by phytic acid.
• Small amounts. The effect is per meal. A few nuts between meals has little impact on the minerals in your dinner.

It isn't all bad. Phytic acid is also an antioxidant, and researchers are studying it for potential benefits, including its role in preventing some kinds of kidney stones. The goal isn't to eliminate it. It's to stop overloading on it without realizing.

Does soaking nuts reduce phytic acid?

This is where the advice falls apart.

The idea of soaking or "activating" nuts was popularized by Sally Fallon Morell's Nourishing Traditions and the Weston A. Price Foundation. You soak nuts in salt water for hours, then dry them at a low temperature, to "unlock" their nutrients. Activated nuts now sell at a premium in health food stores.

In 2020, researchers at the University of Otago in New Zealand put it to the test. They soaked almonds, hazelnuts, peanuts and walnuts, whole and chopped, for 4 to 12 hours in salt water or plain water. The results, published in Food Chemistry:

• Phytic acid barely moved. Changes ranged from -12% to +10%, and some soaked nuts ended up with more.
• Minerals went down. Soaking washed out some of the minerals, especially from chopped nuts.
• No improvement in absorption. The ratio of phytic acid to minerals, the number that predicts absorption, didn't improve.

The authors concluded that their findings "do not support claims that 'activating' nuts results in greater nutrient bioavailability."

The bottom line: soaking may not be a perfect solution to improving a high-phytate nut. The practical fix is to start with a low phytic acid one.

The lowest phytic acid nut: macadamias

Macadamias came out lowest in both comparisons. They're also:

• Low in oxalates. About 90% less than almonds.
• Soft and buttery. They're easy to chew and digest, with no papery skin.
• The richest nut in healthy fats. They carry the same monounsaturated fat that makes olive oil healthy, plus rare omega-7s.
• The lowest nut in omega-6, the fat people are cutting back on when they avoid seed oils.

No soaking, no dehydrating, no premium "activated" price tag. They're low in phytic acid to begin with.

Skip the soaking

If you've been activating almonds to make them easier on your body, macadamias do the job without the prep. House of Macadamias sources raw macadamias directly from farmers in South Africa, with nothing added. [Our raw macadamias are available here](PRODUCT LINK: Raw Macadamia Nuts).

How to lower phytic acid without giving up nuts

1. Swap your default nut. Macadamias or pistachios instead of almonds or cashews.
2. Watch almond flour and almond butter. They're the easiest way to stack phytic acid without noticing.
3. Eat nuts between meals. Phytic acid mainly affects minerals eaten at the same time, so a snack at 3pm interferes less with the iron in your dinner.
4. Pair iron-rich foods with vitamin C. Vitamin C helps counter phytic acid's effect on iron absorption.
5. Don't rely on soaking. It takes hours and the research shows little benefit for nuts.

FAQ

Which nuts are highest in phytic acid? Almonds are the highest in phytic acid among common nuts, followed by cashews and pistachios, according to a 2006 study that compared 10 nuts with the same lab method. Almond flour and almond butter carry the same load.

Which nuts are lowest in phytic acid? Macadamias are the lowest in phytic acid of the common nuts, with less than half the amount in almonds. Peanuts and pecans are also relatively low.

Does soaking nuts remove phytic acid? Barely. A 2020 University of Otago study found that soaking almonds, hazelnuts, peanuts and walnuts for up to 12 hours changed phytic acid by only -12% to +10%, and lowered their mineral content.

Are activated nuts healthier? The research doesn't support it. The same 2020 study found "activating" nuts did not improve mineral availability. Choosing a naturally low-phytate nut is a simpler way to cut phytic acid.

Is phytic acid bad for you? In large amounts, phytic acid reduces how much iron and zinc you absorb from a meal, which matters most for people with low iron, vegetarians and vegans. In moderate amounts, as part of a mixed diet, it's less of a concern and may have antioxidant benefits.

Do macadamia nuts have phytic acid? Yes, but very little. Macadamias had the lowest phytic acid of 10 common nuts in a 2006 comparison, at about 150 mg per 100 g compared with 350 mg in almonds.

Does roasting reduce phytic acid in nuts? Roasting reduces it slightly, but not enough to turn a high-phytate nut into a low one. Phytic acid is quite heat-stable.

The takeaway

The nut-soaking ritual solves a real problem the hard way. Phytic acid does block minerals, but soaking barely touches it. Picking the nut that's low in phytic acid to begin with takes zero hours and works every time.

References

1. Venkatachalam M, Sathe SK. Chemical composition of selected edible nut seeds. Journal of Agricultural and Food Chemistry. 2006;54(13):4705-4714.
2. Kumari S, Gray AR, Webster K, et al. Does 'activating' nuts affect nutrient bioavailability? Food Chemistry. 2020;319:126529.
3. Schlemmer U, Frølich W, Prieto RM, Grases F. Phytate in foods and significance for humans: food sources, intake, processing, bioavailability, protective role and analysis. Molecular Nutrition & Food Research. 2009;53(S2):S330-S375.
4. Fallon S. Nourishing Traditions. NewTrends Publishing, 1999.