7–10 minutes
Woman’s war with her salt
How come most of women I see have thyroid issues? how much iodine is actually in a tablespoon of table Salt that we consume?
That question somehow ended up at connecting dots of Gandhi’s Dandi March, Japanese diet and why women are still being told their symptoms are just stress. This is how most of my rabbit holes go.
The math, and where it breaks down
So. The math first, because it helps to understand the big picture.
A tablespoon of table Salt is about 17–18 grams. For eg. Tata Salt carries 34–35 ppm of iodine and it is above the 15 ppm consumer minimum. That is roughly 578 µg of iodine per tablespoon. Our daily requirement is 150 µg as per FDA. Looks like we are fine, right? But the issue is that nobody uses a full tablespoon in a day. Typical our daily cooking uses maybe 5–6 grams to the maximum of 10 grams. That gives us 170–210 µg on paper.
ON PAPER.
Here’s the part that is not mentioned on the packaging. Iodine is volatile. It evaporates. It is susceptible to heat. Pressure cooking is the thing most Indian kitchens run on daily. This destroys up to 51% of the iodine in your salt before it reaches your mouth. Boiling loses 37–40%. Even steaming and microwaving (idli, dhokla) loses around 20% and 23% respectively.
Adding salt toward the end of cooking, not at the beginning. could help to an extent. Keeping the salt in an opaque (away from sunlight), airtight container (like a ceramic or dark plastic jar) helps to prevent it from the loss of iodine.
Iodine is only the raw material
Iodine is not secreted in the body. It has to be outsourced. But even if you get the iodine in, that’s not the end of the story.
The thyroid is not a simple input and output machine. Iodine enters the thyroid via a transporter called NIS (sodium-iodide symporter). This transporter runs on the difference in sodium concentration between the inside and outside of a cell. There is a pump called the Na⁺/K⁺-ATPase pump, running 24 hours a day in every single cell in your body, maintaining the concentration gradient. This pump is what makes the transport possible.
Thyroid hormones (T3 & T4) control how fast that pump spins across your entire body simultaneously. When the thyroid fails, the pump slows. Everything slows. Weight, temperature, heart rate, thinking.
I keep on thinking this. The thyroid doesn’t just regulate one thing. It regulates the thing that regulates everything else.
Iodine is only the raw material. Once inside the thyroid, it also needs selenium to convert T4 (inactive) into T3 (active). It needs iron to power the enzyme that attaches iodine to thyroglobulin in the first place. It also needs zinc to allow T3 to enter the cell nucleus and actually work. Sounds complex right? Basically it needs selenium, iron and zinc to function well.
Remove any one of these and the whole chain fails even if you have perfect iodine intake. This is the part that doesn’t make sense when we hear the the standard eat iodized salt ads or even double iodized salts.
I think, who have thyroid issues would have got the advise of not to consume the cruciferous vegetables like cauliflower, cabbage. Because the goitrogens from raw cruciferous vegetables blocking iodine at the very point of entry. Some studies say that fluoride (maybe in the water or other sources) suppresses the NIS transporter itself. Strict vegetarian diets too that remove the other major iodine sources fish, shellfish, dairy, eggs. Iodized salt was supposed to be the solution. It was necessary.
The history
India is a coastal nation. We had sophisticated salt-making traditions long before the British arrived. Odisha salt, Tamil marine salt, Rajasthan’s Sambhar Lake, Gujarat’s salt pans. Natural unrefined salt both from coastal and rock sources. It carried trace minerals including iodine from the ocean environment. Hope so. I couldn’t trace literatures back.
In 1765, Robert Clive made salt a monopoly. The Salt Act made producing own salt a criminal offense punishable by imprisonment. A physical barrier, the Great Hedge of India was built thousands of kilometers long, guarded by over 12,000 armed officers, to stop desperate people from smuggling cheaper salt across internal borders. Salt prices rose over 300%. (Kindly read the book –Uppuveli for better understanding)
And then this is the part that stays with me when goitre appeared in epidemic proportions across India, the most influential British medical voice on the subject, Dr. Robert McCarrison, rejected the iodine deficiency explanation. By the 1920s, the USA and Switzerland had already proven that iodized salt eliminated goitre. McCarrison refused to accept it. They did leave a huge impact on us.
Because accepting the iodine explanation would mean accepting that British salt policy had caused mass disease across the subcontinent for years and years.
After independence, surveys found that 226 out of 267 districts were endemic to iodine deficiency. India only began the National Goitre Control Programme in 1962. Universal salt iodization was mandated in 1986. After 10 years, goitre prevalence declined measurably and the IQ levels of schoolchildren improved. Currently, this program called as National Iodine Deficiency Disorders Control Programme (NIDDCP).
Even now, majority of rural households wash their salt before cooking. A habit from when British-era salt was dirty and impure. Unknowingly washing out the iodine that was supposed to protect their thyroids.
When Gandhi walked 388 kilometres to pick up a handful of salt from the sea, he was reclaiming a mineral that had been deliberately priced out of reach of the poorest people for 150 years.
Japanese Diet
While India was being systematically stripped of its iodine, somewhere on the other side of the world, Japanese women were eating seaweed or iodine rich every single day.
The average Japanese woman consumes somewhere between 1,000 and 3,000 µg of iodine daily against our recommended 150 µg. Not from supplements. These mostly from kombu in dashi, wakame in miso soup, nori in everyday meals. Seaweed is not a superfood trend there (It’s just food. I know it is not easy for us to include this in our diet).
Japanese women also have among the highest life expectancy. Researchers have spent decades trying to isolate which variable is doing the work on the iodine, the selenium-rich fish alongside it, the fermented foods, the overall dietary pattern, the gut microbiome shaped by generations of the same diet. The honest answer is probably all of it. It is not simple to extract one element and transplant it.
But the iodine piece is real. There’s a growing body of research suggesting that iodine plays a role in breast cell health beyond the thyroid, which in turn explain why women with chronic iodine deficiency show higher breast cancer risk. Yet to be further explored.
What the Japanese reference actually tells me is not eat more seaweed (though that’s not a bad idea) but they also manage the excess iodine with Soya products (goitrogens) . It’s that 150 µg as a daily target was built on the assumption that this is what a healthy adult needs to avoid deficiency. Not what optimal looks like for a woman’s body across her lifetime. The floor was set. The ceiling was never seriously explored in women as it is complex. Maybe, that’s why most of studies are on male. Yet thyroid in male is underexplored.
India’s 11% hypothyroidism rate is among the highest in the world. Japan’s is among the lowest. The colonial history explains a lot of the gap. But the gap itself is worth sitting with.
Ellu urundai was not accidental
The thing I keep returning to is that ellu urundai was not accidental.
Sesame (common names as til, ellu) carries selenium, zinc, iron, calcium, magnesium, lignans with phytoestrogenic activity, and healthy fats. All in one seed. The thyroid gland contains the highest selenium concentration of any organ in the body. Without selenium, iodine is useless even if it is present abundant. And sesame, combined with jaggery, delivers selenium and iron together in the same handful.
Gingelly oil carries sesamin and sesamolin with anti-inflammatory properties. The oil usually taken with parupu podi or even with kali of different millets. Maybe Jyothika promoted this more than ever one could.
These combinations were not randomly developed. They were developed by women, for women based on thousands of years of observations. Now, the science is catching up.
What’s the connection of sesame with Peter Gregory ? Yet to be explored!!!
Where this ends up
This was started with me questioning on iodine content in a salt packet. This ended up thinking about biology, colonial policy and politics, the Great Hedge of India, and why traditional South Indian. How these food might have been quietly thyroid medicine for centuries without anyone naming it as such?
This is where I find interesting about agricultural systems and food systems. The surface question is almost never the actual question I think. Maybe the actual question almost always connects us to something structural and deep.
The salt was always political (Uppuveli says too). The thyroid is related to female. And ellu urundai was always more than a snack.
Cheers!
Disclaimer: Not a medical advice
PS: Hoping to explore more for X² Club
Check out the previous post: #DecodeAgri26: The Clean Farming, Layers!, Thaai Kizhavi (2026) Movie Review
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Sunandhini R
