Iodine is a mineral crucial for people’s health as well as for optimal functioning.
Iodine’s central role is the production of thyroid hormones – the T4 hormone which contains four iodine atoms, and the more active T3 hormone which contains 3 iodine atoms.
Thyroid hormones play hundreds of roles related to our exchange of materials, temperature regulation, heart rate and more.

During pregnancy and early life (the first 1-2 years) thyroid hormones play a central role in brain development.
Lack of iodine in the mother during pregnancy and while nursing may lead to cognitive damage and, in cases of serious deficiency, even to retardation in the newborn.
Numerous researchers world-wide claim that iodine deficiency during pregnancy and while nursing is liable to lead to a decrease of between 8-12 IQ (intelligence quotient) points.

Is there an iodine deficiency among residents of Israel?
A comprehensive study from 2016 examined thousands of pregnant women and children in Israel, from all sectors (secular, religious, Jews, Arabs), and came up with worrying data.

85% of the women in Israel had lower than normal levels of iodine in their urine. Among children, 62% of them had lower than normal iodine levels.

Among pregnant women, the average iodine level in their urine was 61 micrograms per liter, while the appropriate level for a woman during pregnancy should be between 150-249 micrograms per liter. This level is certainly liable to affect the IQ level of the unborn child.

In comparisons with other countries around the world, Israel is located in the lower ten vis-à-vis the iodine levels in the population. It is likely that one reason for this lies in the amount of treated water which is consumed in Israel (water containing no iodine at all), as well as mass use of water filtering and powerful home filters, such as reverse osmosis.
There is definitely good reason to filter the drinking water in Israel, but the price paid in most cases is water devoid of iodine.

So what do we do? Which foods contain iodine and is it necessary to take a supplement?

Iodine is found primarily in the sea and thus in foods which originate in the ocean, such as fish and seaweed.
Dairy products and eggs also contain respectable levels of iodine (with reservations which we will address further on).
As regards plants, iodine levels are highly dependent upon the level of iodine in the earth in which the fruits and vegetables are grown.

Given the deficiency present across all sectors in Israel, it is clear that the iodine levels of the earth in Israel are low and insufficient. Thus, plant-based foods such as vegetable, fruits and so on cannot be considered a source of iodine in Israel.

Let’s analyze each of the abovementioned sources and see whether they truly represent sources for iodine.

Let’s begin with dairy products and eggs.
The quantity of iodine in them is highly dependent upon the amount of iodine in feed given to cows/goats and the amount in chicken feed.
I was unable to locate figures for the amount of iodine in dairy products and eggs marketed in Israel.
Similarly, there is no information regarding iodine levels in organic eggs.
From research carried out in Israel in 2016 which found that 85% of pregnant women suffered from a lack of iodine, and given that consumption of dairy products and eggs is high in Israel, the conclusion may be drawn that these foods do not represent a sufficient source of iodine (if they contained appropriate levels of iodine we would not have discovered iodine deficiencies among the great majority of women and children).

So, we are left with fish and seaweed

Fish contain iodine; quite a lot of iodine, actually.
We are referring only to fish from the sea.
Farmed fish from pools do not contain sufficient levels of iodine.
The problem with fish is that they contain heavy metals and other toxins.
It is therefore not a good idea to eat too much fish.
There are undoubted benefits to eating 1-2 portions of fish weekly during pregnancy.
The fish will not only supply iodine but also Omega 3 of the DHA and EPA varieties. It is, however, important to take care to eat only small fish and preferably those who live at sea rather than those who are farmed.
In other words, preference should always be given to sardines rather than tuna (a very large fish) or salmon (fish grown in crowded fish farms). The reason for choosing smaller fish is the fact that small fish contain significantly less toxins relative to larger ones.

So what do vegetarians and vegans, who don’t eat fish, do?
What about all those people who simply don’t like fish?

So, we find ourselves left with one last source of iodine – seaweed.
Seaweed is considered a food for health nuts.
They add it to salads, shakes and various foods.

Vegetarians and vegans who do not consume fish and are health-aware, have added the various seaweeds to their menus:
Wakame, Hiziki, Kombu and of course, Nori from which Sushi is made.

The question is whether seaweed really is healthy?
Are they a reliable source of iodine?

We went out to check.
We present to you here the comprehensive study we undertook regarding seaweed sold in Israel.

For a number of years now it was been known that seaweed has a tendency to adsorb arsenic.
We purchased every type of dried seaweed sold in Israel from healthy food stores and sent them to be tested for arsenic levels at a certified lab.

Arsenic is a toxic, dangerous metal.

Exposure to arsenic in food does not cause immediate symptoms or medical problems. Even casual exposure on occasion to food containing large quantities should not have adverse effects.
Problems occur with chronic, continual exposure over many years.

Below are the health consequences as found in studies, regarding long-term exposure to arsenic in food or water:

An increased risk of the following malignant illnesses: lung cancer, skin cancer and bladder cancer. Source 1, source 2, source 3, source 4, source 5 The World Health Organization defined arsenic as a carcinogen.
Increased risk of high blood pressure. Source
Increased risk of heart disease. Source 1, source 2
Increased risk of type 2 diabetes (adult diabetes) source 1, source 2
Arsenic causes neuron damage (brain nerve cells) source 1, source 2
Increases the risk of cataracts source
Narrowing of the neck veins which supply the brain – increased risk of a stroke. Source
Among young people, exposure to arsenic can lead to damage to attention, memory and ability to learn, general damage to intelligence and difficulties with social adjustment/. Source 1, source 2, source 3, source 4, source 5
Arsenic passes through the placenta to the fetus. Significant consumption of arsenic in food during pregnancy may lead to an increased risk of birth defects and developmental problems. Source 1, source 2
Are there guidelines regarding arsenic levels in food?
If so, what are they?

There are guidelines.
In Israel, in most foods, the guidelines are for 1 mg of arsenic per kg of food.
The same applies to seaweed.
In the case of dried seaweed and food supplements containing seaweed, the guidelines refer to an arsenic level of up to 5 mg/kg.

Over these levels it is forbidden for these foods to be sold in Israel!
In many other countries around the world as well, the permitted arsenic levels is similar to the Israeli guidelines.

You may rightly ask why the food guidelines are set at 1 mg of arsenic per kg while for dried seaweed they are five times higher. The answer is that if the same guidelines were applied to the dried seaweed and seaweed supplements, it would be impossible to sell them.
So they simply changed the guidelines in order to market them to the public…
But let’s put that aside for a moment…

The results of our study:

(To view the original lab reports, click on the name of the seaweed)

The findings are problematic.
To put it mildly…

All of the dried seaweeds sold in Israel far exceed the guidelines for dries seaweeds (5 mg/kg); by over a hundred percent!

In effect, according to the Ministry of Health guidelines, these seaweeds ought not to be entering Israel or being sold here!

So, ask yourselves, how is this even being sold?
The answer is simple.
The fact that there are guidelines does not imply any sort of enforcement.
The Ministry of Health does not have the enormous, unlimited budget (a euphemism) at the disposal of the Rambam Medicine Center and they do not test the arsenic levels of seaweed imported here.

So what are the conclusions?
Is it forbidden to eat seaweed?
Is sushi no longer an option?

We’ll address sushi and Nori seaweed further on.
Let’s begin the other varieties of seaweed.

Hiziki, Kombu and Wakame –
My advice is to refrain from consuming these varieties completely.
They contain the largest quantities of arsenic of all the varieties and species of seaweed which we examined.
The health-conscious public, believing that seaweed is a healthy food, eat relatively large quantities of these seaweeds, without realizing they are introducing extremely large amounts of arsenic into their bodies.

So, is there a variety of seaweed which is possible and recommended to eat freely?

Yes.
There is another brand of seaweed sold in Israel with a completely acceptable level of arsenic!
It is an Israeli brand.
That’s right.

It turns out that in Israel, like in Japan, fresh seaweed had been grown in recent years.

An Israeli company called Seakura grows seaweed in a supervised manner in pools located on land.
The pools contain sea water which undergoes a unique process which reduces the levels of toxins in the water.
These are seaweeds called Ulva, or in its botanic name Ulva ohino.
Naturally, we sent these as well for arsenic-level testing.

Attached link to the lab report for the Ulva seaweed

Less than 0.1 mg/kg.
Testing discovered a level of 0.1 mg/kg.
The instrument did not identify any arsenic and thus there is no precise number, but rather a guarantee that the result is less than 0.1 mg/kg.

You may say, rightly, that the comparison is unfair.

Ulva is a fresh seaweed (sold as frozen seaweed in stores), while the others are dried.
It is natural and logical that dried seaweed would contain much higher levels of arsenic than fresh or frozen.
One ought to compare apples with apples, and not apples and bananas…
After all, if we dried the Ulva seaweed, we would likely also discover arsenic levels which exceed the guidelines.

A correct assumption.
So we sent off the dried Ulva to be tested.

The arsenic levels in the dried Ulva seaweed were found to be 2.55 mg/kg.

Attached link to  the original lab report for the dried Ulva seaweed

These results not only meet the guidelines for dried seaweed (less than 5 mg/kg), but are significantly lower than any other dried seaweeds sold in Israel.

It emerges from our study that the Ulva seaweed is the cleanest of all seaweeds sold in Israel and I definitely recommend its consumption.
It is a wonderful source of iodine without the drawback of high levels of arsenic.

Does everyone need to take iodine supplements?

This is a difficult question to answer.
One thing, however, is for certain.
Vegetarians and vegans, who do not eat fish, must get iodine from seaweed of from a supplement.
The same goes for pregnant and nursing women.
The required amount of iodine during pregnancy and nursing rises significantly.
Due to its great importance for the development of the fetus and newborns, it is a good idea for every pregnant/nursing woman to check for adequate iodine levels, whether the mother is vegetarian or not.

It is always preferable to get minerals and vitamins from whole foods rather than as a separate entity.
This is not always possible.
If it is possible, there is no doubt that it is significantly better than consuming synthetic supplements.
The synergy of hundreds of elements together which compose whole foods means that in the large majority of cases it is better than isolating the single active material in a lab.
This is the reason why I am not in favour of supplements containing only iodine, and certainly not when it is possible to receive the iodine as part of a whole food such as seaweed.

As I mentioned, given the results of our research, I recommend only Israeli Ulva seaweed as a source of iodine. The other seaweeds, unfortunately, are highly polluted.

In some health-food stores you can find the frozen seaweed and incorporate it into your diet (soups, salads, spreads, cooked dishes and more), but be careful because the taste is quite dominant, and is unfamiliar for the Israeli palate. It may not be to everyone’s taste, or even edible.

Today there are other natural alternatives:
There are nutritional supplements containing Ulva seaweed available in capsules.
A whole food wrapped up in a capsule, rather than an isolated iodine supplement.

Seakura dry their seaweed, grind it into powder and package it in capsules, making it possible to consume iodine even without eating seaweed- simply by taking a supplement made of concentrated seaweed.

Most people will not eat fresh seaweed (or fresh which has been frozen) on a regular, daily basis, and the availability is rather limited as well.
The solution for all those people who do not eat fresh/frozen seaweed is to consume dried Ulva seaweed as a supplement.

There is no doubt that this is the right, natural way to consume iodine.
From whole foods alone.
Given the availability of the supplement, the fact that this is a whole food and not an isolated mineral, today this is the way I recommend that my patients consume iodine.
Ulva seaweed, as a whole food, apart from the iodine, also contains a large quantity of magnesium and other minerals and of course hundreds of anti-inflammatory, anti-cancer materials and various vitamins.

It’s grown under organic conditions without animal by-products.
I am very cautious when selecting the products and supplements I recommend, and only do so following an in-depth, comprehensive examination insofar as is possible.
I visited Seakura’s facility, saw the large growing pools and learned about the unique method employed for purification of the sea water pumped into the pools in which the Ulva seaweed is grown.
I was extremely impressed both by the company and by the product quality.
The facility contains unique ecological technology for growing seaweed in a controlled manner on land.
The company exports most of their seaweed to other countries and fulfills the stringent standard required for heavy metals, pesticides and biological pollutants.
I was particularly pleased to see that there is finally an iodine supplement which is not synthetic and which gets this important mineral from whole food, clean from toxins (not zero toxins but the least amount possible in our unclean world).

I recommend this Ulva seaweed supplement for every pregnant, nursing woman and for all vegetarians/vegans.

Recommendations by the health authorities world-wide refer to consumption of at least 150 micrograms of iodine per day for adults.
For pregnant women the indications are for at least 220 micrograms of iodine daily, and for nursing women health authorities recommend at least 290 micrograms of iodine daily.
Each Ulva seaweed capsule contains 150 micrograms of iodine, so the regular dose (for men, or for women who are neither pregnant nor nursing) is one capsule daily.
During pregnancy and nursing the dose is two capsules daily.
I have recommended that all women of childbearing age take one Ulva seaweed capsule daily, in order to begin pregnancy with a sufficient store of iodine.

With one small act you can ensure a supply of iodine from a natural source, whole and free of toxins, and thus ensure maximization of the newborn’s cognitive abilities.

In my opinion, Ulva seaweed should be an integral part of every pregnant and nursing woman’s toolbox, as well as a part of the supplements taken by vegetarians/vegans or anyone who eats very little fish (regular fish eaters get iodine from fish).

Following research on the world of iodine and iodine supplements, the Israeli product of whole Ulva seaweed, as a whole food containing iodine in the concentrations recommended by health authorities, is, in my opinion, the most natural and highest quality iodine supplement available, not only in Israel but world-wide.

The Ulva seaweed nutritional supplement may be purchased at various health food stores and at a reduced price through Rambam Medicine Center.

Yours,
Gil Yosef Shachar MD