Today’s post is in response to a reader’s question about the potential impact of phytic acid and the raw vegan diet:
I know you addressed this in general a few years ago, but I have struggled a lot with the information about phytic acid content in nuts and seeds, and the effect this has on mineral absorption, making it undesirable to consume nuts and seeds raw since roasting and soaking can lower phytic acid levels the most. This information makes me want to avoid nuts and seeds, even though they seem healthy in other ways.
On a raw food diet, is there enough mineral content consumed that the amount not absorbed due to phytic acid wouldn’t matter? The research I’ve seen quoted online is showing that soaking alone might be removing approx 50% of phytic acid content in general, with results different by seed/grain type.
How does one ensure mineral absorption is sufficient when elimination of phytic acid is not possible completely through soaking, without eating nothing but fruits and vegetables? Can we sustain fully on fruits and vegetables alone?
This is a great question Derek and a subject that is very important for everyone. Phytic acid is found in many foods including grains, beans, nuts and seeds. Herbivores such as cows and sheep have the ability to breakdown phytic acid but many animals – including humans – cannot.
This can be a problem because phytic acid interferes with our ability to absorb important nutrients like iron, zinc, calcium and magnesium. In one study when phytic acid was removed from wheat, absorption of iron was increased by 1160%, which is about twelve times more than from regular wheat. Research also suggests that absorption of magnesium from food is up to 60 percent higher when phytate is absent.
In addition to blocking mineral absorption, phytic acid also inhibits the normal function of digestive enzymes including pepsin and trypsin, which are involved in protein digestion, and amylase, which is involved in the digestion of starch.
The levels of phytate in foods tends to vary a lot depending on how a food is grown, stored and processed. Phytic acid content has been found to be much higher in foods grown using high-phosphate fertilizers than those grown with natural methods.
So simply choosing organic foods will allow you to reduce the levels of phytic acid in your diet. Other methods including soaking, sprouting and dehydrating can significantly reduce phytic acid levels.
Phytic Acid and Grains
In the case of certain grains such as wheat, soaking and fermenting, such as in the process of making sourdough bread, can practically eliminate the impact of phytic acid. Sprouting also reduces phytic acid levels significantly. However, for many people wheat is not an ideal food because it contains high levels of gluten and a lot of people have a gluten intolerance.
In the case of quinoa it is possible to neutralize up to 77 percent of phytate by soaking for 12 hours before cooking. Up to 98 percent of phytic acid can be reduced by soaking, sprouting, fermenting and then cooking quinoa. For other grains including corn, millet, oats and brown rice these methods are not sufficient.
Phytic Acid in Raw Nuts and Seeds
Unfortunately there isn’t a lot of research on how efficiently we are able to reduce the phytic acid levels in nuts and seeds. Many raw nuts and seeds – such as Brazil nuts, almonds, walnuts, hazelnuts and pumpkin seeds – do contain quite high levels. As such it is probably best not to consume large amounts of raw nuts and seeds due to their potentially negative impact on mineralization and digestive function.
It seems reasonable to assume that soaking and sprouting will have a similar effect with nuts and seeds as it does with grains, although we can’t know for sure. Regardless, if you choose to include nuts and seeds in your raw food diet their digestibility is greatly enhanced by soaking and then dehydrating until crunchy. My personal experience is that they are much easier to digest when prepared this way.
A lot of raw foodies will probably be disappointed to find out that unfermented raw cacao – which is actually a seed – is one of the foods very high in phytate. Some brands of raw cocoa may be fermented so to be sure you will need to contact the manufacturer to verify this. However, personally I don’t recommend including cacao in your diet on a regular basis due to the potential toxic effects of raw cacao.
Can You Absorb the Minerals from Raw Nuts and Seeds?
So the question then becomes: Can we obtain nutritional benefits by including nuts and seeds in a raw food diet or does the presence of phytic acid neutralize any potential gains?
Let’s just look at one example. In the case of raw pumpkin seeds a 100 gram portion provides 15 mg of iron (83% of the recommended daily value), 535 mg of magnesium (134% of the recommended daily value) and 7.5 mg of zinc (50% of the recommended daily value). These are certainly impressive results for a portion that provides just over 500 calories. But what value are these minerals if the body is unable to absorb them?
Nevertheless, even when you consider the mineral-binding effect of phytic acid it is likely that the food will still provide some minerals in a useable form – especially if you prepare your seeds by soaking and dehydrating. If 60 percent of the magnesium is blocked due to phytic acid, there is still 321 mg available in this portion of raw seeds, and this would be even higher after following the recommended preparation methods.
However, it is important to be aware of the potential of the mineral-binding effect when combining phytic acid with other foods. For example, using a nut or seed based dressing on a salad may reduce your absorption of magnesium and other minerals from your raw leafy greens.
Phytic acid only reduces mineral absorption during that meal but doesn’t impact on overall nutrient absorption throughout the day. So if you consume a handful of sprouted pumpkin seeds as a snack you may absorb less iron, zinc and magnesium from the seeds, but not from the foods that you eat several hours later.
Are There Any Seeds That Don’t Contain Phytic Acid?
Some people claim that hemp seeds, chia seeds and flax seeds don’t contain phytic acid. Unfortunately this does not appear to be the case so they should be regarded in the same way as other raw nuts and seeds.
Phytic Acid in Coconut
While coconut does contain a moderate amount of phytate, research indicates that the mineral-binding effects of phytic acid in coconut is almost non-existent.
Traditionally coconut is usually eaten raw and there are not any special techniques used to process it – as is generally the case with grains, beans, nuts and seeds. In the tropics it is consumed as a staple food where it has served as a source of nourishment for thousands of years without any apparent negative effects.
Phytic Acid and Digestive Health
It is also interesting to note that certain species of digestive microflora have the ability to produce the enzyme phytase, which breaks down phytic acid. This indicates that people who have a healthy balance of intestinal flora may have a greater ability to tolerate foods containing phytic acid.
As is often the case, it could be more important for us to focus on enhancing general health – and that of the digestive system in particular – than on micromanaging the details of our dietary intake.
Can You Get Enough Nutrition Eating Only Raw Fruits and Vegetables?
The question of whether we can fully sustain ourselves on fruits and vegetables alone does not have a simple answer. Every person has a unique health situation and individual requirements can vary. Certainly with the recent increase in popularity of raw food diets there are many people living on raw fruit and vegetables and very successfully. If you include avocado, olives and coconut – which are botanically regarded as fruits – then it becomes much easier to imagine living on a diet that consists of fruit and vegetables alone.
Fruits and leafy greens are some of the most nutritious foods available to us, they are generally easy to digest and less likely to contain anti-nutrients like phytic acid. There are some exceptions. For instance, potatoes contain just as much phytic acid as seeds, and this is not reduced by any method of cooking. Phytic acid is also found in trace amounts in foods like berries and green beans.
Eating only fruits and vegetables is one way to cleanse your body with a raw food detox diet for a period of several months, up to a year or even longer. Nuts and seeds are generally not ideal foods when you are attempting to heal the digestive system and restore optimal kidney function. Additionally, those with chronic bone disorders would probably do best to emphasize raw leafy greens – especially green juices – in order to enhance mineralization.
However, for the most part when people follow a raw food diet for a longer time period they do begin to incorporate more variety into their diet. The important factor is to keep limit portion size of nuts, seeds, grains and legumes and to properly prepare these foods by soaking, sprouting and dehydrating to maximize their nutritional potential.