THE FOOD · INVESTIGATION
Minerals:
the vitamins'
quieter
cousins.
Vitamins get all the attention.
Minerals just quietly keep the lights on.
Ask someone to name a vitamin and they'll usually fire one back immediately. Vitamin C. Vitamin D. Maybe B12 if they've been tired lately.
Ask someone to name a mineral, and there's a longer pause. Iron, probably. Maybe calcium. After that, things get vague — despite the fact that the nutrition label on nearly everything in your kitchen lists sodium, potassium, calcium and iron right alongside the vitamins, in the same box, with the same percentages.
Minerals never got the marketing. There's no "mineral C" cold-and-flu aisle, no minerals-gummies industry, no minerals equivalent of the sunshine vitamin story.
are they doing
down there on the label?
Let's give them the same treatment.
What even
is a mineral?
Minerals are inorganic elements your body needs in small amounts to function — things like calcium, iron, magnesium, zinc, potassium, sodium and iodine.
That word "inorganic" is the whole difference between minerals and vitamins.
Vitamins are organic molecules, built around carbon, made by plants, animals or fungi, and vulnerable to being broken down by heat, light or air. Minerals are elements, straight from the periodic table — absorbed by plant roots from the soil, or eaten by the animals that ate those plants, and passed along the food chain to you, structurally unchanged.
by overcooking it.
You cannot destroy an element.
Cooking can leach minerals out of food into the cooking water, which is why the broth from boiled vegetables isn't nutritionally empty. But the mineral itself, once it exists, exists. Nothing in your kitchen can chemically break it apart.
Once inside your body, minerals get to work on some fairly load-bearing tasks: building bone, carrying oxygen in your blood, sending nerve signals, keeping your heart beating in rhythm, and holding the right amount of water inside and outside your cells.
Quiet, in other words, is not the same as minor.
Why do some get
"macro" and others
just "trace"?
Nutrition science splits essential minerals into two groups, and the split has nothing to do with how important a mineral is.
It's purely about quantity — how much of it your body actually needs.
optional. It means small.
The macrominerals are the ones you need in relatively large amounts — over 100 milligrams a day, sometimes much more.
The trace minerals — iron, zinc, iodine, selenium, copper, manganese and a handful of others — are needed in amounts small enough to measure in micrograms or milligrams, sometimes a thousand times less than a macromineral.
And yet a trace-level shortfall in iron or iodine can affect a person's entire life — their energy, their cognitive development, their pregnancy outcomes. Size of the dose and size of the consequence are not the same measurement.
MACRO AND TRACE, SIDE BY SIDE
Same job description.
Very different dosage.
Macrominerals
Needed in gram or multi-hundred-milligram amounts daily. Structural and electrical: bone, fluid balance, nerve and muscle signalling.
Trace minerals
Needed in milligram or microgram amounts. Highly specific jobs: oxygen transport, immune function, thyroid hormone production.
Neither column is the "important" one. A severe sodium imbalance can be fatal within hours. A long-term iodine shortfall can quietly reshape a child's cognitive development before anyone notices a symptom. Both are minerals. Neither is optional.
So what happens
when you don't
get enough?
Because minerals do such different jobs, a shortfall in one looks nothing like a shortfall in another.
Can cause fatigue, pale skin and reduced oxygen delivery — the world's most common nutrient deficiency.
Long-term shortfalls can weaken bone density over years, since the body borrows calcium from bone to keep blood levels stable.
Can impair thyroid function and, during pregnancy, affect a baby's brain development.
Can weaken immune function and dull taste and smell.
Can affect muscle and nerve function and heart rhythm.
Can disrupt muscle contraction and, in severe cases, heart rhythm.
Six minerals, six completely different failure modes.
A NUMBER THAT DEPENDS ON YOU
Not everyone
needs the same
amount.
Most mineral reference values are single numbers. Iron's isn't, and the reason why says a lot about how personal nutrition actually is.
the recommended daily iron intake for women of reproductive age
Roughly double the 8mg recommended for adult men — because regular menstrual blood loss means regularly replacing lost iron.Iron deficiency is, by a wide margin, the most common nutrient deficiency on the planet, affecting an estimated two billion people worldwide according to the World Health Organization — disproportionately women, young children and people who eat little or no meat, since iron from plant foods is absorbed far less efficiently than iron from animal foods.
So a genuinely useful question isn't:
"Am I getting enough of every mineral, generically?"It's:
"Given who I actually am — my sex, my diet, my life stage — which of these am I actually at risk of running short on?"MEET A FEW OF THEM
Okay, so what are these
minerals actually doing?
There are around twenty essential minerals in total. You don't need to memorise all of them — I certainly didn't set out to.
But a handful of them come with genuinely interesting stories.
So let's meet six.
CALCIUM
More bank vault than bone.
Calcium is best known for building bones and teeth, and that's genuinely most of what it does — about 99% of the calcium in your body is stored there.
The other 1% is doing something arguably more urgent: circulating in your blood, where it's needed for muscle contraction, nerve signalling and blood clotting.
If your blood calcium dips, your body can pull calcium out of bone to correct it — a short-term fix that, repeated over years without enough dietary calcium coming in, can leave bones weaker.
Dairy is the obvious source, but leafy greens, tofu set with calcium, fortified plant milks and small bones in tinned fish all count too. Vitamin D matters here as well — it's what lets your gut actually absorb the calcium you eat.
IRON
Two kinds, two absorption rates.
Iron's main job is riding inside haemoglobin, the molecule in your red blood cells that actually carries oxygen from your lungs to the rest of you.
Not all dietary iron behaves the same way. Heme iron, found in meat, poultry and fish, is absorbed efficiently — often 15 to 35% of what you eat. Non-heme iron, found in beans, lentils, spinach and fortified grains, is absorbed far less efficiently, often under 10%.
Vitamin C converts non-heme iron into a form the gut absorbs more easily — which is the actual mechanism behind the old "spinach and orange juice" advice, not a coincidence.
Coffee and tea do the opposite: their tannins bind to non-heme iron and reduce absorption, which is why the advice for people managing low iron is often to leave a gap between meals and their morning cup.
MAGNESIUM
The quiet cofactor.
Magnesium doesn't do one dramatic thing. It does hundreds of small ones — it's a required cofactor for more than 300 enzyme reactions, including ones involved in energy production, muscle and nerve function, and building the structural framework of bone.
True magnesium deficiency is uncommon in otherwise healthy people, since your kidneys are good at conserving it. But intakes below the recommended level are fairly common, particularly in diets low in the foods that carry it: nuts, seeds, whole grains, legumes and leafy greens.
ZINC
The one people reach for when they're sick.
Zinc plays a genuine role in immune function, wound healing, and the senses of taste and smell — which is why a zinc deficiency can leave food tasting strangely flat.
It's also the mineral behind those zinc lozenges people reach for the moment a cold starts.
A 2024 Cochrane review found weak, low-certainty evidence that zinc might shorten a cold by around a day or two when taken early, with no meaningful effect on preventing colds in the first place, and a real chance of nausea or an unpleasant taste as side effects.
Zinc from plant foods is also less available to the body than zinc from meat and shellfish, since compounds called phytates in grains and legumes bind to it — a genuine reason vegetarian and vegan diets are usually planned with a bit more attention to zinc sources.
POTASSIUM
Not actually a banana exclusive.
Potassium keeps fluid balanced across your cells and is essential for nerve signals and muscle contraction — including the muscle that happens to be your heart.
The banana reputation isn't wrong, exactly. It's just incomplete.
So do beans, lentils, leafy greens, oranges and yoghurt. The World Health Organization recommends adults get at least 3,510mg of potassium a day — and most people, across most countries studied, fall short of that while simultaneously eating more sodium than recommended. We'll come back to that imbalance shortly.
IODINE
The public health success story nobody talks about.
Iodine has exactly one job, but it's an important one: your thyroid needs it to make the hormones that regulate metabolism in essentially every cell in your body.
It's also, quietly, one of nutrition's great success stories. In the early twentieth century, goitre — a visibly swollen thyroid caused by iodine deficiency — was common enough in parts of the inland United States that the region became known as the "goitre belt." The fix was almost absurdly simple: add iodine to table salt.
Which makes it a slightly awkward moment for today's specialty salts. Sea salt, kosher salt and Himalayan pink salt are often not iodised, and as they've displaced ordinary table salt in a lot of kitchens, iodine intake has quietly drifted down in some populations — a reminder that even a solved problem can come back if nobody's watching it.
THE QUESTION I ACTUALLY CAME FOR
Okay, but do I need
a mineral supplement?
So minerals are essential, they behave nothing like each other, and running low on some of them — iron and iodine especially — is genuinely common.
Which brings us to the question underneath most of this article.
But minerals raise
the stakes a bit.
The logic is familiar by now:
With minerals, that last step deserves a bit more scrutiny than it does with most vitamins.
THE FUEL-TANK ANALOGY, WITH A CATCH
It's still a lot like filling up your car.
Once the tank is full, more fuel doesn't help. But unlike some vitamins, several minerals — iron especially — have no efficient exit route once you've absorbed too much. Your body has no good way to actively excrete excess iron, so it accumulates in organs like the liver and heart instead of simply washing out.
Which is exactly why "just in case" is a worse argument for minerals than it is for most vitamins.
SO I WENT LOOKING
What does the evidence
actually say?
One of the largest tests of mineral supplementation is the Women's Health Initiative, which followed over 36,000 postmenopausal women given calcium and vitamin D supplements for around seven years.
Calcium and vitamin D supplementation modestly increased hip bone density, but did not significantly lower the overall risk of hip fracture across the study population — and it increased the risk of kidney stones.
That's not a verdict that calcium doesn't matter. It matters enormously if you're not getting enough of it from food. It's a verdict that adding more, once you're already covered, isn't the guaranteed upside it's often sold as — and, in this case, came with a genuine downside attached.
"mineral supplements don't work."
It means the same distinction from the vitamin conversation applies here, with slightly higher stakes.
So when do mineral
supplements actually
make sense?
Pregnancy — iron and iodine needs both rise
Heavy menstrual periods
Vegan or vegetarian diets, particularly for iron, zinc and iodine
A documented deficiency confirmed by bloodwork
Older age, particularly for calcium alongside vitamin D
Living somewhere with iodine-poor soil and little iodised salt or seafood in the diet
The less useful question is:
"Should I take a mineral supplement, generically?"The more useful one is:
"Is there a specific mineral, and a specific reason, behind this particular bottle?"Bloodwork answers that question far better than guessing does.
THE MINERAL WE LOVE TO HATE
A quick word
about sodium.
Sodium spends most of its cultural life as a warning label. Which makes it easy to forget that it's also an essential mineral, needed for fluid balance and nerve signalling, exactly like the others in this article.
that sodium exists.
The World Health Organization recommends adults keep sodium under 2,000mg a day — about a teaspoon of salt — while most people, across most countries measured, consume well beyond that. Very little of it comes from the salt shaker on the table. Most of it is already baked into bread, sauces, cured meat and restaurant food before it ever reaches you.
Which puts sodium and potassium in an odd, connected spot: too much of one mineral and too little of another, working against each other on the same outcome — blood pressure — in most of the populations that have been studied.
And, as the iodine story showed, sodium isn't even just sodium: for a lot of people, it's also their main source of iodine. Cut salt entirely without thinking about where else iodine comes from, and you can accidentally solve one problem by creating another.
BACK TO WHERE WE STARTED
Remember that blank
spot on the label?
The mineral section of a nutrition label looked, at first glance, like an afterthought under the vitamins.
It isn't telling you:
to the real nutrients."
It's telling you something closer to:
That's the other half of the story.
SO, WHAT DID I ACTUALLY LEARN?
Small on the label.
Not small in the body..
I started this thinking minerals were the smaller, quieter half of the label — the part next to the vitamins that nobody really talks about.
They're not smaller. They're just built differently: elements instead of molecules, absorbed instead of synthesised, with at least one of them — iron — genuinely more risky to over-supplement than most of the vitamins I looked at earlier.
Eat a variety of whole foods — plants and animal foods both bring different minerals to the table.
Know which ones apply to your specific situation — iron for menstruating women and plant-based eaters, iodine for anyone who's cut salt without a second thought.
Let bloodwork, not guesswork, decide whether a supplement is actually correcting something.
Not because minerals are dangerous. Most of them, in ordinary food amounts, are about as far from dangerous as nutrition gets.
Not a boring footnote on the label.
Not something to megadose "just in case."
And not something to fear, either.
AND MAYBE THAT'S THE PART I WAS LOOKING FOR
Understanding gives us
better questions to ask.
I don't think the lesson of minerals is that we need to learn twenty new names and their reference values.
I think it's that the boring-looking part of the label was quietly doing just as much work as the exciting part.
"Am I getting enough of every mineral?"
becomes"Which of these actually applies to me, given my body and my diet?"
"Is there a documented reason for this particular supplement?"
"Am I quietly under-eating potassium while over-eating sodium, like most people?"
And if the honest answer to most of those is "I'm probably fine"?
to being background information.
Because nutrition is supposed to exist within our lives.
Not become a periodic table we have to memorise before breakfast.
I came into this expecting a footnote. I'm leaving with a slightly different opinion of table salt, a genuine appreciation for whatever nutritionist first paired spinach with orange juice, and a little more respect for the boring half of the label.
Vitamins and minerals both. Neither one is the sidekick.
READ THE EVIDENCE
Sources
- National Institutes of Health, Office of Dietary Supplements. Fact sheets for calcium, iron, magnesium, zinc, potassium, iodine and sodium.
- World Health Organization. Guideline: Sodium Intake for Adults and Children; Guideline: Potassium Intake for Adults and Children.
- World Health Organization. Iron Deficiency Anaemia: Assessment, Prevention and Control.
- European Food Safety Authority. Dietary Reference Values for calcium, iron, magnesium, zinc, iodine, potassium and sodium.
- Jackson, R. D., et al. (2006). Calcium Plus Vitamin D Supplementation and the Risk of Fractures. New England Journal of Medicine (Women's Health Initiative).
- Nault, D., et al. (2024). Zinc for the Common Cold. Cochrane Database of Systematic Reviews.