Is Phytic Acid Good or Bad?
Phytic acid can cause nutrient absorption and utilization problems , particularly in those whose diet relies heavily on high phytic-acid containing plant foods.
Phytate is the salt (minerally chelated) form of phytic acid (free acid) - mineral nutrients (mostly magnesium, potassium and calcium – all positive ions) are stored in grains, seeds, nuts, and legumes bound to phytic acid and are released when broken down by phytase enzymes. Phytate accumulates in the seeds during their ripening period.
Phytate presence in the diet can cause mineral deficiencies in the body by forming metal-phytate complexes – phytic acid can bind to positively charged mineral ions (cations) in the GI tract due to the negative charges on its phosphate (P) groups, which give phytic acid its chelative (binding) properties over a broad pH range. Minerals at risk of being bound by phytic acid include magnesium (Mg++), calcium (Ca++), iron Fe2+/3+), zinc (Zn2+), manganese (Mn2+), copper(Cu2+), potassium (K+), sodium (Na+), cobalt (Co++). In the long-term, an early sign of this is chronic tooth decay.
Phytic acid negatively impacts utilization of protein and starch/carbohydrate by inhibiting enzymes needed for their digestion:
- Pepsin to break down protein in the stomach
- Amylase to convert starch into sugars
- Trypsin for breaking down proteins in the small intestine;
- Phytic acid negatively affects lipid absorption
Detrimental health effects of phytic acid
Detrimental effects of phytic acid can be reduced – by using food preparation techniques, such as SOAKING, GERMINATING and/or FERMENTING to activate naturally present (or added)phytase enzymes to break down the phytic acid. The overall benefits are that the food is:
- More digestible
- Has higher bioavailable nutrients
- Has less nutrient-depleting anti-nutrients
Phytic Acid Also Confers Some Beneficial Effects
Particularly when consumed in moderation. Protects against a variety of cancers - mediated through:
- Antioxidant properties,
- Interruption of cellular signal transduction,
- Cell cycle inhibition
- Enhancement of natural killer (NK) cells activity.
- ype 2 diabetes
- Coronary heart disease
- Kidney stone formation
- Heavy metal toxicity;
What Foods Contain Phytic Acid?
Phytate Is Found In High Amounts In Seeds And Unrefined (Whole) Cereal Grains (In The bran and the outer hulls), also found in the outer hulls of beans/legumes, nuts and other seeds. Some examples of phytate content in grains, legumes, nuts and seeds:
- · Some nuts have higher phytate content than some grains
- · Vegetables have relatively small amounts
- · Brans have extremenly high phytate content
See the chart: Phytate Content of Certain Foods. Note: Food items marked in red on this chart are not permitted on DBM programs.
What Is Phytase And What Does It Do?
Phytase is any type of phosphatase enzyme that breaks down phytic acid (chemically called dephosphorylation, produces a phosphate ion and a molecule with a free hydroxyl group) - phytase catalyzes the hydrolysis (requires water) of phytic acid by removing a phosphate group from its substrate to release a usable form of inorganic phosphorus. Phytase activity is measured in FTU (a worldwide standard).
The break down of phytic acid by phytases results in two pointed beneficial effects – both of which increase mineral availability and absorption (esp. bone-beneficial phosphorus)
(1) Allows the utilization/absorption of bound/stored nutrients in phytate – phytase can hydrolyze phytic acid, releasing phosphorus and other nutrients bound by phytic acid (E.g. minerals, protein and starch );
The binding is possible within a phosphate group or between two phosphate groups on either the same or different phytic acid molecules;
(2) Prevents phytic acid from binding to important minerals in the digestive tract – which would otherwise make them unavailable to the body.
Humans (and other non-ruminants) produce very few phytase enzymes for breaking down phytate –Humans and animals with one stomach (i.e. do not chew the cud) are unable to access the nutrients tied up in phytate. Note that even mice have 30 times more phytase than humans and therefore the results of rodent studies examining phytic acid breakdown and therefore do not likely apply to humans.
In whole seed/grain, germination activates phytase - which breaks down phytate and releases phosphorus and other minerals needed by the developing plant embryo for new growth.
Some grains contain more phytase than others – E.g. wheat contains 14 times more phytase than rice; rye contains over twice as much phytase as wheat.30 (the reason rye is preferred as a starter for sourdough breads).
- Some grains contain insufficient phytase to eliminate their phytate - E.g. corn, oats, brown rice, millet), even when properly prepared.
- In contrast - wheat, rye and barley contain high phytase levels.
Phytase Activity Depends On pH
Phytase activity depends on pH with Ideal pH being somewhere in the ~4.5 - 5.5 range –adding a mild acid to soaking water of phytate foods creates that “just right” pH environment for phytase action. Note that the stomach acid pH is much lower and not conducive to phytase activity.
“pH was the most important factor in reducing the content of phytic acid during bread making as phytic acid in doughs with pH 4.3–4.6 was more effectively reduced than in doughs with higher pH.”
Phytase activity and degradation of phytic acid during rye bread making by Merete Møller Nielsen · Marianne Linde Damstrup · Agnete Dal Thomsen · Søren Kjærsg˚ rd Rasmussen · Åse Hansen Eur Food Res Technol 2007
Reale et al concluded that lactic acid bacteria improved conditions for degrading phytate simply by lowering pH – they determined the ideal pH to be ~ 5.5
Reale A, Konietzny U, Coppola R, Sorrentino E, and Greiner R, 2007, ‘The importance of lactic acid bacteria for phytate degradation during cereal dough fermentation’, Journal of Agriculture and Food Chemistry, 55 (8), pp 2993-2997 ACSPub
Phytase activities are pH dependent with the highest activities being observed at a slightly acidic pH ( 5.1).
Food Reviews International Phytic Acid by Lori Oatway a; Thava Vasanthan b; James H. Helm Field Crop Development Centre, Lacombe, Canada b Department of Agricultural Food and Nutritional Science, University of Alberta, Edmonton, Canada
Bacterial flora in the colon produce phytase and also lactic acid that affects pH in favorof phytase activity – dephosphorylation of phytate releases Calcium ions, which are absorbed from the colon
Sandström, B., Cederblad, A., Stenquist, B., & Andersson, H. (1990). Effect of inositol hexaphosphate on retention of zinc and calcium from the human colon. European Journal of Clinical Nutrition, 44, 705–708.
Phytase Activity Depends On Temperature
Phytase activity is increased within an ideal temperature range.
Phytase is reduced/destroyed by:
- Steam heat - 176 ⁰F (80 ⁰C) in 10 mins. or less
- Heat-processing – such as being in a wet solution at 131-149 ⁰F (55 – 65 ⁰C)
Peers FG. Phytase of Wheat. The Biochemical Journal 1953 53(1):102-110.
Extruded bran and whole grain cereals (E.g. All-bran ®, Bran Buds) are a recipe for digestive disaster and mineral deficiencies - Slurries of extremely high phytate grains are forced through tiny holes at high temperatures and pressures, which destroy the phytase enzymes that might have broken down some of the phytate - snap, crackle and pop goes your health!
Commercial oats have high phytic acid content but no phytase (destroyed by heat processing).
Freezing and long storage times - fresh flour has more phytase than after being stored.
Campbell J and others. Nutritional Characteristics of Organic, Freshly stone-ground sourdough and conventional breads. http://eap.mcgill.ca/publications/EAP35.htm.
Cooking alone is NOT enough to activate phytase for a significant reduction of phytic acid in grains and legumes – and cooking temperatures eventually destroy phytase altogether. To reduce phytic acid to a healthy level requires some preparation before cooking:
- Legumes should ideally be sprouted (i.e.germinated) or soaked in acidulated water as another option
- Grains should either acid soaked (i.e. partially fermented) then optionally sprouted (i.e. germinated) OR they should be soured (fully fermented as in sourdough)
Conclusions on phytic acid consumption
Everything in moderation – consuming phytate has both beneficial and harmful effects on the body, and as with most things, balance is the key. However, high-phytate foods have become a staple, not only in developing countries, where cost is the driving factor, but also in the developed ones, which choose to put grains at the bottom of the food pyramid. A moderate intake of phytate from occasional higher phytate whole foods is not a problem for anyone in good health on a traditional, balanced diet, which includes vitamins from animal fats and a little fruit. However, If high phytate foods comprise the main food source of two or more meals per day (usually true of today’s typical Western diet or a vegetarian diet), then to avoid a mineral deficiency, you should:
- Obviously maintain a diet that includes the full spectrum of nutrients
- Remove some of the phytate - either by omission or by utilizing various food preparation methods
- At least mitigate phytate’s mineral-blocking effects
How To Increase Mineral Absorption When Consuming Foods With A High Phytate Content
- Chronic dental decay is an early clue that you are dealing with a mineral deficiency
- Ensure dietary fat-soluble vitamins A and D from animal fats (lard, butter, cream, fish liver oil, organ meats) to aid absorption of vitamins and minerals contained in grains (calcium, phosphorus, iron, B vitamins, etc.) and any others you have eaten
- Include Beta-carotene in your daily diet – to counteract phytic acid reduction in iron absorption; found in brightly coloured fruits and vegetables.
- Consume vitamin C with phytate-rich meals – counters iron loss
- Obtain absorbable calcium – raw goat milk, raw goat cheese, goat yogurt, goat kefir, bone broths
- Obtain vitamin D - Get out in the sun - vitamin D –which has been shown to mitigate mineral-blocking effects of phytic acid
- Consume Lactobacilli-containing probiotics – lactic acid production lowers pH creating an environment more conducive to phytase activity and these bacteria also produce some phytase; look for a quality supplement with a minimum 30 billion CFU/day including multiple acid-resistant species/strains; eat / drink good probiotic-containing goat yogurt and goat kefir.
- Several traditional household food preparation methods can be used to enhance the bioavailability of nutrients in high phytate foods - These include heat treatment (cooking/roasting), mechanical processing (E.g. grinding), soaking (partial germination),germination (sprouting), fermentation (souring).
- Remember to check with your DBM Physician if goat / sheep dairy is permitted on your program
Read more about Probiotics by following the link.
Soak high-phytase enzyme containing foods (usually in acidified liquid) to begin germination.
- When soaking a low-phytase food, add some high-phytase grain flour (whole grain rye, wheat, triticale, buckwheat or barley flour) - to help break down phytic acid in the low-phytase food.
- Read more on soaking nuts and seeds here
- Read more on soaking grains here
- Read more on soaking legumes here
Germinate/Sprout (completely germinate grains or legumes)
- Sprout lentils and other legumes to increase phytase activity / reduce phytate.
- Optionally sprout grains – to further reduce phytate and anti-nutrients after soaking.
- Read more on sprouting on this link