Overview
Phytic acid, or phytate, is a naturally occurring compound found in a variety of plant foods like seeds, grains, nuts, and legumes. Often referred to as an “antinutrient,” phytic acid has gotten a bit of a negative reputation, but it’s not all bad.
Yes, phytic acid does bind to essential minerals like iron, calcium, and zinc, making them harder for our bodies to absorb. However, research shows that phytic acid also has surprising benefits: It acts as a powerful antioxidant, protecting cells from damage and even helping prevent certain cancers, particularly colon cancer.(1)(2)
Since phytic acid is found in so many nutritious foods, avoiding it altogether is neither practical nor necessary. The key is balance. By using simple food preparation methods like soaking or sprouting, you can significantly reduce the impact of phytic acid on nutrient absorption.
In this article, we'll explain the mechanism by which phytic acid affects nutrient absorption, discover some of its surprising health benefits, and share simple, effective tips to stop it from stealing your precious nutrients.
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How Phytic Acid Affects Nutrient Absorption
Phytic acid has a unique way of affecting mineral absorption due to its chemical properties. It binds tightly to key minerals like iron, calcium, magnesium, manganese, and zinc, forming complexes that our digestive system struggles to break down. This binding occurs because of phytic acid's phosphate groups, which latch onto these positively charged minerals, making them less available for absorption.(3)
Essentially, this process can reduce the bioavailability of important minerals, especially in diets that rely heavily on high-phytate foods. However, phytic acid doesn’t block all mineral absorption—just a portion of it.
But don't worry—there are simple and effective strategies to counteract phytic acid's potential negative effects. Later in this article, we'll explore practical techniques that can help you minimize phytic acid's impact on nutrient absorption, allowing you to enjoy the benefits of whole grains, nuts, seeds, and legumes without sacrificing your nutritional needs.
Foods High in Phytic Acid
Now that we've learned how phytates interfere with mineral absorption, here's a quick look at some foods high in phytic acid, along with their estimated phytic acid content:
Legumes (Lentils, chickpeas, beans)
These contain moderate amounts of phytic acid. For example, about 100 grams (a cup) of chickpeas can have 0.2 to 2 grams of phytic acid, depending on preparation methods.
Nuts (almonds, walnuts)
Nuts are higher in phytic acid, with around 0.5 to 9.4 grams per 100 grams of nuts. This means eating a handful (30 grams) can give you up to 3 grams of phytic acid.
Whole Grains (oats, brown rice, wheat)
Whole grains typically contain 0.4 to 1.2 grams of phytic acid per 100 grams. A serving of oats (about half a cup) might have about 0.5 grams of phytic acid.
Seeds (sunflower, flax, pumpkin)
Seeds are among the richest sources, with 1.4 to 9 grams of phytic acid per 100 grams. A tablespoon of flaxseeds, for instance, could have 1 gram of phytic acid.
Tubers (potatoes, sweet potatoes)
Tubers contain lower amounts, with approximately 0.2 grams per 100 grams, making them a lesser source of phytic acid compared to grains or legumes.
Simple Ways to Reduce Phytic Acid
If you're looking to improve nutrient absorption from plant foods, there are several traditional methods that can help. Sprouting, soaking, fermentation, and food pairing are proven techniques to reduce phytic acid. These approaches not only make minerals more available but also enhance digestion and overall health. Below, we’ll explore each method in more detail and provide practical examples of how they work.
Sprouting
Sprouting, also known as germination, triggers a biochemical process in grains and legumes that naturally reduces phytic acid levels. This process activates enzymes like phytase, which break down phytic acid, thereby improving the bioavailability of essential minerals such as iron, zinc, and calcium.
For instance, a study published in the International Journal of Food Science and Nutrition (2008) found that germinating chickpeas can reduce their phytic acid content by up to 80%, making minerals more accessible for absorption. This method is widely recognized for its effectiveness in enhancing the nutritional quality of plant-based foods.
Soaking
Soaking grains and legumes overnight in water or a mildly acidic solution, such as lemon juice, can effectively break down phytic acid. This process, often referred to as "pre-soaking," is a cornerstone of traditional cooking methods.
Studies show that soaking at increased temperatures can significantly reduce phytic acid content, enhancing mineral bioavailability, especially when grains like brown rice undergo prolonged soaking.(4)
Fermentation
Fermentation, the process where beneficial microorganisms break down carbohydrates, is an effective method to reduce phytic acid. Foods like sourdough bread, fermented legumes, and yogurt not only support digestion but also improve mineral absorption.
Research highlights that during sourdough fermentation, lactic acid bacteria break down phytates, significantly reducing phytic acid levels. Various studies, including a detailed review by MDPI, show that sourdough fermentation can lower phytic acid by 40% to over 90%, depending on fermentation time and conditions.(5)(6)
Food Pairing
There’s plenty of credible research that has shown that pairing foods rich in vitamin C with foods rich in non-heme iron can improve iron absorption. This is because vitamin C helps convert iron into a more bioavailable form.
For instance, pairing foods like lentils with citrus fruits or tomatoes can significantly improve iron absorption. Additionally, eating probiotic-rich foods like yogurt or kefir with meals can help with digestion and the absorption of essential minerals like calcium and iron.
Phytic Acid is More Than Just a Nutrient Thief!
Phytic acid, often viewed as a nutritional villain due to its ability to bind with minerals, has a surprising twist: it may also offer significant health benefits.
Beyond its role in reducing mineral absorption, phytic acid acts as a potent antioxidant. This means it can help protect your cells from damage caused by harmful molecules known as free radicals. Free radicals are strongly implicated in a variety of chronic diseases, including cancer, heart disease, and diabetes.
Moreover, recent research highlights phytic acid’s promising role in kidney stone prevention. One study shows that phytic acid may help reduce the formation of calcium oxalate crystals by binding to calcium in the gastrointestinal tract. This binding forms insoluble complexes, thereby decreasing calcium absorption and lowering urinary calcium excretion. As a result, the overall risk of stone formation is reduced.
Additionally, a study published in Phytochemistry Reviews suggests that phytic acid may help lower blood glucose levels by inhibiting certain digestive enzymes, slowing carbohydrate digestion, and reducing the absorption of glucose. This process could be particularly beneficial for individuals managing diabetes
In a 2020 study published by the National Institutes of Health (NIH), researchers investigated phytic acid's impact on cancer cells. They found that phytic acid could inhibit tumor growth by regulating enzymes involved in cell proliferation. This discovery has sparked interest in exploring phytic acid as a potential component of cancer prevention strategies. However, more extensive research is necessary to fully understand its long-term benefits in this area.
Should You Be Worried About Phytic Acid?
The short answer? No, not if you're eating a balanced diet. Phytic acid is found in nutrient-dense foods like whole grains, nuts, seeds, and legumes, all of which offer numerous health benefits. However, concerns can arise if a diet relies heavily on these foods without much variety, especially for individuals with higher mineral demands or those on predominantly plant-based diets.
For vegetarians and vegans, who naturally consume more high-phytate foods, the reduced absorption of minerals such as iron, zinc, and calcium might be more noticeable. This is particularly relevant for people with higher mineral needs, such as pregnant women, growing children, athletes, or individuals recovering from illness.
In such cases, incorporating methods like soaking, sprouting, fermenting, and pairing phytate-rich foods with vitamin C-rich ingredients can help enhance nutrient absorption.