What exactly is phytic acid? Is it found in rice and pea protein? Should you be worried about it? Phytic acid has been a hot topic in the nutrition world with arguments going back and forth on whether or not it is beneficial, especially as discouraged by popular diets such as the Paleo diet. One major drawback is that it can limit the absorption of certain beneficial minerals in the body, while a major benefit is that the foods containing it have a large role in decreasing risks of cancer, controlling diabetes, and even possibly helping with HIV/AIDs (1). With the pros and cons of phytic acid it’s no surprise people have been left wondering whether or not it is safe or harmful to consume.
So, what exactly is phytic acid?Phytic acid or phytates, are a unique substance found naturally in many plant foods like edible seeds, grains, legumes/beans and nuts. Phytates are not absorbed by the body (because our bodies don’t produce the enzyme to break it down) but they do function within the body. Also, they are not essential like vitamins and minerals. Different foods contain different amounts of phytates. This is important when talking about the degree to which they can positively or negatively affect the body (2). Below is a table listing the most common foods with phytic acid and the amounts they have been found to contain:
|Food||Phytic Acid (% of dry weight)|
Source: Authoritynutrition.org (3)
For comparison, the rice protein and the pea protein concentrates used in our Growing Naturals products contain approximately 0.7% and 1.7% phytic acid respectively--amounts that are in the lower range compared to other sources of phytic acid.
Technically speaking, phytic acid is the main storage form of phosphorus (a mineral) in plant tissue. It can be found in the bran or hulls of all seeds. This is why phytate levels are highest in un-sprouted seeds and also the reason why sprouting is a recommended way of reducing the phytate content. Phytic acid is also known as inositol hexaphosphate, or IP6.
Benefits of Phytic Acid
One of the most talked about benefits of phytic acid is its role as an antioxidant. Being an antioxidant means it plays a huge role in protecting the body from, not only every day stressors, but ones that have damaging effects over time, such as cancer. Phytic acid is actually used in diet treatments for colon and rectal cancers (1). Scientists believe these beneficial effects may be due to phytic acid binding with iron and reducing oxidative damage to cells in the colon.
Some animal studies have shown that dietary phytate stops the growth of cancerous cells in the liver and pre-cancerous cells in the pancreas (1). In cell studies, they have also been shown to stop the growth of human leukemia cells, cervical cancer, melanoma, muscle cancer and others (3). Other cancers (i.e. breast and prostate) appear to be affected by phytic acid as well; however researchers don’t quite understand the connection yet.
It’s difficult to pin point exactly how phytic acid affects cancer because other substances in the food (phytochemicals, vitamins, minerals, etc.) may or may not be helping out too. So it becomes very complicated and additional research is still needed to draw conclusions. However, it is clear that phytic acid-containing foods have been linked to many health benefits.
For example, scientists understand that foods containing phytic acid protect us from heart disease. Well documented research has shown that phytate-containing foods have the ability to help lower cholesterol and lipid levels in the blood—all things which directly impact heart disease (1). One particular group of phytate-containing foods, legumes (which include peas, beans, nut, seeds, etc.), have been found to play an important role in diabetes (1,5). They are known as a low glycemic index food, meaning the carbohydrates they do contain, break down much slower than their counterparts (simple sugars/high glycemic foods), resulting in a slower increase in blood sugar levels in the body. This allows for the body’s insulin, and the body itself, to avoid being overwhelmed with high blood sugars. Legumes also contain some protein which slows digestion and also the absorption of sugars.
It is theorized that phytates may actually play a direct role in diabetes. One study found that when they compared digestion of cereals (with no phytates) and legumes (with phytates), legumes had a slower release of sugar in the blood, which led the scientists to believe the phytates played an important role in the breakdown, as well (5). Phytic acid-containing foods (because of their typical high fiber content) can help with keeping the stomach fuller longer. In turn, this helps in decreasing calorie intake and may promote weight loss.
Some studies have even shown that phytic acid can help reduce inflammation, which is something that plays a big role in a lot of diseases (1). Although only in the beginning stages, phytic acid is now being studied with the HIV/AIDS virus showing some good results with lowering the spread of the virus in the body. (1) Moreover, dental cavities, which are highly common in school-aged children, have been shown to be prevented with phytic acid (1). Although not as popular, there have been a few studies that have shown benefits of phytin, a mixture of phytic acid (IP6) and salt that has been isolated from plants. It has been shown to peel away dry surface cells, therefore supporting anti-aging and skin care treatments. Phytin has also been shown to enhance brain function (1).
Issues with Phytic AcidThe high levels of phytic acid in the brans or hulls of raw seeds/grains have been known to reduce absorption of minerals like iron, zinc, magnesium, and calcium. These minerals are important in bone health, intestinal health, and our immune system, among many, many other roles. However, this only affects the meal or food with which the phytic acid was consumed—not other meals or foods throughout the day. This occurs because phytic acid naturally binds with these minerals as they go through the body undigested.
Specific benefits/roles of these minerals:
- Iron: carries oxygen throughout the body, helps muscles store and use oxygen, and is an essential part of some proteins and enzymes (6).
- Zinc: helps the immune system and making of DNA, plays an essential role in growth and development, and is important in the senses of taste and smell (7).
- Magnesium: involved in protein syntheses, muscle and nerve function (including the heart), blood glucose control, and blood pressure regulation. Also required for energy production (8).
- Calcium: required for muscle and vascular function, hormone secretion, and supports bone and teeth structure (9).
Due to its chemical structure, phytic acid can also bind to proteins and starches, causing a decrease in availability of these nutrients, thus making it difficult for our bodies to absorb them (1). This is why phytic-acid is sometimes referred to the “anti-nutrient.” Although this can lead to unfavorable effects (in certain people), it can actually benefit people with kidney disease (for example) who need to control the amount of calcium or magnesium they get. When binding to calcium in the blood, it can also decrease the chances of formation of kidney stones in people who are prone to them. Phytic acid can also bind to lead, lowering its toxic effects and thereby treating acute lead poisoning (1).
Numerous studies have looked at the harmful effects of phytates in the body and the results indicated that consuming these high phytate foods did contribute to mineral deficiencies in various populations, specifically children and people in developing countries (10,11,12). But these populations are already at risk for mineral deficiencies, so how do we know it was specifically due to phytic acid? Would it be different if these populations were using the methods to reduce the phytates? Or what if they just consumed more foods that were higher in the affected minerals?
With this in mind, a couple of studies found that when the calcium concentrations were higher in the diet as compared to the phytic acid content in foods, the absorption of calcium was not affected (2,5). This could mean that as long as you are consuming enough of these minerals or pair them with certain foods, their absorption may not be as affected by the phytic acid. Although not as well documented, some research has hinted at problematic effects of phytic acid on digestion, enzyme activity in the body, and metabolism (1). However, much more research is needed to confirm. With the trend of raw food diets on the rise, here lies an important point about the harm in consuming raw legumes.
Before legumes are cooked they contain high levels of lectins. Lectins are naturally occurring substances in the plants that cause biochemical changes to animal cells. These changes are not always good. Although not all lectins are bad, the ones found in some legumes have been shown to cause problems with growth and stomach upsets like diarrhea, nausea, bloating, and vomiting. Other issues that have been noted throughout research are: decreased absorption of fats, B12, and nitrogen, along with overgrowth of “bad bacteria” in the intestinal lining. Heat (cooking) changes the chemical structure of lectins and therefore reduces it’s toxic effects (1).
Should you be worried?
For most people with well-balanced diets, phytic acid is rarely a problem. In fact, removing foods with phytic acid from your diet is a bad idea because most of them are very nutritious and health-promoting. Nonetheless, there are certain groups of people who should be careful of phytate intake. For example, infants, vegans or vegetarians, people in undeveloped countries or those who have been diagnosed with mineral deficiencies.
How do I reduce the phytate content of foods?
Luckily, there are several methods that can help to reduce the phytate content of foods or to increase the mineral’s availability to the body. So far research shows all of these methods work equally well and one does not work better than the other (1, 2). Sprouting is one option that can be done at home, or purchased second hand. Once the seeds sprout, the phytates are degraded and the phosphorus is released. It also can help release even more nutrients out of the grain (such as B vitamins, vitamin C, folate, fiber, and essential amino acids often lacking in grains such as lysine). Sprouted grains can be bought in stores, cooked and/or used in a meal. Sprouted grain flours are another option, which can be used in baking (13). Here are some recipes for sprouted dishes. Soaking the grains is another option. Whey and milk products (e.g. milk, buttermilk or sour milk) are the most common liquids used for soaking. However, it has recently been debated about soaking grains in these liquids because some research has shown that the calcium in the milk affects the reduction of phytates. If this is worrisome or if dairy is not an option, some alternatives are coconut milk (or kefir made from coconut milk), apple cider vinegar (raw), or lemon juice. You can read about it in more detail and get recipes here (14). Baking or utilizing a long rise time and an acidic pH content can also decrease the phytic acid content if you make your own bread.
Enhancing Mineral AbsorptionOften times, by consuming different combinations of nutrients, it's possible to make nutrients more available for the body to use. This is extremely helpful when ensuring you get the minerals from the phytate-containing foods. The presence of animal protein or ascorbic acid (vitamin C) in a food or meal with phytic acid has been documented to enhance the absorption of minerals like iron, especially if the iron is from a plant-based source (15). However, if meat eating is not an option adding vitamin C alone can still increase the absorption of iron. For example, eating broccoli with a splash of lemon juice can help the body better absorb the iron in the broccoli. The allium family of veggies (which include onion and garlic) contains properties, which can enhance mineral absorption when consumed or cooked with foods containing phytate. For example, brown rice cooked with 1-2 cloves of garlic or eaten with 1-2 thin slices of onion was shown to increase the availability of iron and zinc by up to 50% more (16). Magnesium, a mineral that most people in the US are already deficient in, is found in many phytic acid containing foods (e.g. Lentils, seeds, cereals). Consuming higher protein (animal or plant) sources, and/or Vitamin D containing foods (oily fish like tuna or salmon, food products fortified with Vitamin D, cheese, and egg yolks) with these foods can help the magnesium be absorbed more efficiently (17). An example would be consuming brown rice with grilled salmon, topped with pumpkin seeds. Vitamin D can also help absorb calcium. This is why dairy milk is often fortified with Vitamin D—to help absorb the calcium in it. Although vitamin D can be obtained from foods, one simple way to get it is by exposing bare skin to sunlight.
Despite all of the potential issues (which really only affect certain groups of people), phytic acid appears to be a beneficial substance to majority of people. Since it is mostly found in highly nutritious, plant-based foods which are known to improve health, avoiding phytic acid is generally not recommended. Under those circumstances when phytate intake must be regulated, methods for reducing phytate content or increasing mineral absorption should be considered.
Written by: Lindsay Goddard, MS, RDN
Edited by: Scarlett Full, in-house Registered Dietitian
- Admassu, S. “Potential Health Benefits and Problems Associated with Phytochemical in Food Legumes.” East African Journal of Sciences. 2009. 3(2) pp 116-133.
- Lönnerdal B, Sandberg AS, Sandström B, Kunz C.” Inhibitory Efects of Phytic Acid and Other Inositol Phosphates on Zinc and Calcium absorption in suckling Rats.” The Journal of Nutrition. 1989, pp 211-214
- Arnarson, A. PhD. “Phytic Acid: 101; Everything you need to know” Authority Nutrition. 2015 http://authoritynutrition.com/phytic-acid-101/
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- National Institute of Health. “Zinc”. 2015. Retrieved from ods.od.nih.gov/factsheet/zinc-consumer/
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- National Institute of Health. “Calcium”. 2015. Retrieved from ods.od.nih.gov/factsheet/calcium-healthprofessional/
- Van Rensburg et al., "Nutritional status of African populations predisposed to esophageal cancer", Nutrition and Cancer, vol. 4, 1983, pp. 206-216
- Moser, P.B. et al., "Copper, iron, zinc and selenium dietary intake and status of Nepalese lactating women and their breastfed infants", American Journal of Clinical Nutrition 47:729-734, April 1988.
- Harland, B.F. et al., "Nutritional status and phytate: zinc and phytate X calcium: zinc dietary molar ratios of lacto-ovovegetarian Trappist monks: 10 years later", Journal of the American Dietetic Association December 1988. 88:1562-1566,
- Whole Grains Council .“Sprouted Whole Grains” 2013. Retrieved from http://wholegrainscouncil.org/whole-grains-101/sprouted-whole-grains
- Korzeniewski, S. “Soaking Nuts and Grains + Spiced Nut Bars (Gluten Free)”. The Organic Dietitian. 2013. Retrieved from http://www.theorganicdietitian.com/recipe-6-ingredient-spiced-nut-bars-gluten-free/ )
- Hallberg L, Brune M, Rossander L. The role of vitamin C in iron absorption. International Journal for Vitamin and nutrition research 198; 30:103-8. http://www.ncbi.nlm.nih.gov/pubmed/2507689
- Gautam S, Platel K, Srinivasan K. Higher bioaccessibility of iron and zinc from food grains in the presence of garlic and onion. J Agric Food Chem. 2010 Jul 28; 58(14):8426-9.
- Linus Pauling Micronutrient Information Center. Magnesium. Oregon State University. 2015. Retrieved from http://lpi.oregonstate.edu/mic/minerals/magnesium