Antinutrients
Phytate - antinutrient / malabsorption agent
Phytic Acid - "Malabsorption Agent"
Phytic Acid / Phytate - Malabsorption Agent
What is Phytic acid / Phytate?
Phytic acid and its salt phytate
(both generally referred to as phytate) is a plant seed's storage form for
~70% of its phosphorus (also the B-vitamin inositol)
- most of the seed's phytate is broken down to release phosphorus and other nutrients,
as a food source for the sprouting seed.
Phytic acid is especially found
in cotyledons and outer hulls of the seeds of oil-producing plants - particularly in grains (bran and germ), legumes, nuts,
and other edible seeds. The cotyledon is inside the germ and provides food for the
first leaves.
Shahidi F. (1997) Beneficial Health effects and drawbacks
of antinutrients and phytochemicals in foods In: Shahidi F (Ed) Antinutrients and
Phytochemical in Foods. Am Chem Soc Symp. Series 662
What Foods
contain Phytic Acid
Phytic acid digestibility
Most phytic acid makes it through to the colon undigested
and unabsorbed - phytic acid "laughs" at stomach acid
and is not phased by our intestinal enzymes; in the colon; bacteria that produce
phytase enzymes can begin to break it down, but most phytate leaves the body intact
taking its phosphorus and any bound nutrients with it. Therefore, phytic acid only
interferes with minerals in the GI tract, not in the bloodstream or in our cells.
Phytic acid in food is only about 50%
digestible by NON-ruminants - being able to chew
the cud, ruminant animals can produce the phytase
enzymes required to break down phytic acid. Humans cannot.
Schlemmer, U., Frølich, W., Prieto, R.F. and Grases, F.
(2009) Phytate in foods and significance for humans: food sources, intake, processing,
bioavailability, protective role and analysis. Mol Nutr Food Res 53, S330-S375.
However, humans have other ways to break down phytic
acid in foods to improve their digestibility:
• Phytic acid can be degraded by phytase
enzymes intrinsic to its host food - however, not all
phytic acid-rich foods contain an abundance of phytase E.g. oats and corn do not
• By specific gut flora that produce
phytase enzymes
(more on this at the phytase enzymes link)
• Before consumption using traditional food
preparation methods that produce
phytase enzymes -
i.e. soaking, ideally, followed by fermenting or sprouting.
E.g. properly soaking beans can break down 1/3 to 2/3 of their phytate content.
Cooking / Roasting (E.g. common in manufacturing breakfast cereals) barely degades
phytate, since the heat quickly destroys the phytase enzymes.
How
to prepare grains
How to prepare legumes
Phytic acid has both negative and positive roles in the body
Phytic acid is an antinutrient
- Phytic acid in WHOLE grains, legumes, nuts, and other seeds eaten
by humans and other NON-ruminants is considered an
antinutrient :
"Mineral magnet" -
the grasping "arms" of the phytic acid molecule
tend to bind certain necessary mineral ions (multivalent
cations , such as calcium (Ca++), magnesium (Mg++), zinc(Zn++),
iron(Fe++) copper(Cu++), with 2 positive charges),
both in its host food and also in your digestive tract
to minerals that you consumed in other foods. It does not
tend to bind to univalent mineral ions, such as potassium (K+) and sodium (Na+).
When phytic acid is bound / chelated to a mineral it becomes
phytate
Phytic acid
inhibits enzymes needed for digesting food
-It's snowflake-like molecule
is basically an Inositol B-vitamin) ring with 6 phosphate
groups attached -
C6 H18 O24 P6
(Phytic acid, myoinositol
hexaphosphate, IP6)
Brune M et al. No intestinal adaptation to a high-phytate
diet. American Journal of Clinical Nutrition 1989; 49: 542-545.
Consuming too many phytic acid containing foods on a regular
basis without soaking/sprouting/fermenting / cooking can cause several health issues
related to nutrient availability/utilization
• Cause mineral malabsorption
• Negatively impact utilization
of protein and starch/carbohydrate
However, studies reveal that some people can consume phytic
acid without adverse consequences - possibly mitigated
by:
• Favorable gut flora -
which produce phytase enzymes, and can actually adapt
to a higher phytate (e.g. vegan/vegetarian) diet by increasing their phytase production.
L.H. Markiewicz
, J. Honke , M. Haros, D. Swiaztecka, B. Wroblewsk. Diet shapes the ability of human
intestinal microbiota to degrade phytate -in vitro studies (2013) J. Appl. Microbiology
• Other dietary
contributions - such as concurrent consumption
of
vitamin A
and
vitamin D
(provided in animal fats).
Consumed in moderation, phytic acid also confers
some health benefits:
Phytic Acid - Good for
your health
Do we need to bother preparing foods to remove phytate?
PHOSPHORUS is vital for human bones
and teeth, and health in general but . . . grains, legumes and nuts are not our
best sources - which are meat, fish, dairy, eggs
(a problem if you are a vegan)
Higher amounts of PHOSPHORUS (and
therefore phytate) found in plants grown using today's typical commercial
high-phosphate fertilzers - rather than natural compost.
Srivastava BN and others. Influence of Fertilizers and
Manures on the Content of Phytin and Other Forms of Phosphorus in Wheat and Their
Relation to Soil Phosphorus. Journal of the Indian Society of Soil Science .
1955 III:33-40.
Many cultures consume grains and beans as staples of their diet
- and that includes Westerners, who mistakenly have grains
at the bottom of their food pyramid. Vegans or vegetarians center their
diet around high-phytate foods as sources of protein amino acids.
World Consumption
of Phytic Acid
Conclusions
on phytate consumption
References
Living with Phytic Acid, Weston Price Foundation
