Most women I speak to are surprised when I tell them that you can eat reasonably well, take a multivitamin every day, and still be deficient in several key minerals. Not because they're doing anything wrong — but because Irish soil, Irish food culture, and the realities of modern life create a perfect storm for mineral depletion that very few people talk about.

Minerals don't get the attention vitamins do. You'll see vitamin C and vitamin D on every shelf, in every health food shop, in every magazine article about wellness. But minerals are quietly doing some of the heaviest lifting in your body — and when they're low, the effects are wide-reaching, easy to miss, and very often misattributed to stress, ageing, or simply "being tired".

Here are the five minerals I see showing up as deficient most consistently in the women I work with — and what you can do about it.

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1. Magnesium

Magnesium is involved in over 300 enzymatic reactions in the body. Sleep. Mood. Muscle function. Blood pressure. Blood sugar regulation. Hormone balance. Energy production. There is almost no system in your body that doesn't rely on adequate magnesium — which makes it all the more significant that it is one of the most commonly depleted minerals in the modern Western diet.

Why Irish women are particularly low

Modern food processing strips magnesium from grains. Intensive farming has reduced magnesium levels in soil compared to a generation ago. And critically — stress depletes magnesium rapidly. Cortisol, the stress hormone, causes your kidneys to excrete more magnesium. The more stressed you are, the more magnesium you lose. The more magnesium you lose, the harder it is to manage stress. It is one of the most vicious cycles in nutritional medicine.

Symptoms that might indicate low magnesium

• Poor sleep or difficulty staying asleep
• Muscle cramps, twitches or restless legs
• Anxiety or a constant feeling of low-level tension
• Headaches or migraines
• Constipation
• Fatigue that doesn't resolve with rest
• PMS or worsening perimenopause symptoms
• Water retention

What to do

Not all magnesium supplements are equal — this is important. Magnesium oxide, the cheapest and most widely available form, absorbs at roughly 4%. Your body excretes most of it before it can do anything useful. Magnesium glycinate is the form I recommend most frequently — it is highly bioavailable, gentle on the stomach, and particularly effective for sleep, anxiety and muscle function. Magnesium malate is better suited if fatigue and muscle pain are the dominant symptoms.

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2. Iron

Iron deficiency is the most common nutritional deficiency in the world — and women are disproportionately affected. Menstruation, pregnancy, and the demands of modern life on an often under-nourished body create a recurring cycle of depletion that many women simply accept as normal.

The challenge with iron is that you can be significantly deficient — with ferritin levels low enough to explain profound fatigue, poor concentration, hair loss and breathlessness — and still return a "normal" result on a standard blood test, because standard tests measure serum iron rather than stored iron (ferritin). Many GPs only test serum iron. Many women are told they are fine when they are not.

Symptoms that might indicate low iron

• Persistent fatigue that doesn't improve with sleep
• Pale skin, particularly around the inner eyelids
• Cold hands and feet
• Hair thinning or hair loss
• Shortness of breath with light activity
• A sore or swollen tongue
• Difficulty concentrating
• Rapid or irregular heartbeat
• Premature greying of hair

What to do

Ask your GP specifically for a ferritin test — not just a full blood count. Ferritin measures your iron stores, and it is a far more meaningful number than serum iron alone. If your ferritin is below 50–70ng/mL you are likely experiencing symptoms, even if your GP considers it technically "in range".

If supplementation is recommended, iron bisglycinate is significantly gentler than iron sulphate and far less likely to cause constipation. Always take with vitamin C to enhance absorption, and never alongside calcium or with tea or coffee.

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3. Selenium

This is the deficiency Irish women are least likely to have heard of — and one of the most geographically specific. Ireland's soil is genuinely, measurably low in selenium. This is not a theoretical risk. It is a documented fact that affects the selenium content of virtually every vegetable, grain, and animal product grown on Irish soil.

Selenium is a trace mineral with an outsized role in health. It is a critical component of several antioxidant enzymes that protect cells from oxidative damage, it supports thyroid function (the thyroid requires more selenium per gram of tissue than any other organ), and there is a substantial and growing body of evidence linking adequate selenium status with reduced cancer risk.

Symptoms that might indicate low selenium

• Persistent fatigue and brain fog
• Hair loss or brittle hair
• Weakened immune function — getting every cold going
• Slow metabolism or difficulty losing weight
• Thyroid symptoms including unexplained weight gain, cold intolerance or hair thinning

What to do

The simplest and most effective solution for selenium deficiency in Ireland is two to three Brazil nuts per day. A single Brazil nut contains roughly 70–90mcg of selenium — close to the full recommended daily intake. This is one of the very rare cases in nutrition where a whole food solution is genuinely as effective as supplementation.

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4. Zinc

Zinc is involved in over 200 enzyme reactions. It supports immune function, wound healing, skin health, hormone production, fertility, taste and smell, and DNA synthesis. It is also one of the minerals most consistently low in women following plant-forward or reduced-meat diets — because the zinc in plant foods is significantly less bioavailable than the zinc in animal products.

The challenge with zinc deficiency is that it is notoriously difficult to detect through standard blood testing. Plasma zinc levels are tightly regulated and don't drop meaningfully until deficiency is quite advanced. Symptom assessment is often more clinically useful than blood testing for catching zinc insufficiency early.

Symptoms that might indicate low zinc

• Frequent colds or infections
• Slow wound healing
• Acne or skin breakouts that don't respond to topical treatment
• White spots on fingernails
• Loss of taste or smell
• Dry or rough skin
• Hair thinning
• Hormonal imbalances

What to do

Zinc bisglycinate and zinc picolinate are the most absorbable forms. A standard supplementation dose is 15–25mg per day. One important note: high-dose zinc supplementation over time can deplete copper, as the two minerals compete for absorption. If supplementing zinc for more than a few weeks, ensure you are also getting adequate copper — either through diet (shellfish, nuts, seeds, dark chocolate) or by choosing a supplement that includes both.

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5. Iodine

Iodine is essential for the production of thyroid hormones — and without adequate thyroid hormones, almost everything slows down. Metabolism. Energy. Brain function. Temperature regulation. Mood. The connection between iodine deficiency and thyroid dysfunction is so well established that iodine deficiency remains the most common preventable cause of thyroid disease worldwide.

Surveys consistently show that iodine status in the Irish population is lower than it should be — particularly in women of reproductive age and in those who have reduced their intake of dairy and seafood. The shift away from dairy as a primary food source has coincided with a noticeable increase in thyroid-related presentations in clinical practice.

Symptoms that might indicate low iodine

• Unexplained weight gain
• Fatigue and sluggishness that sleep doesn't fix
• Feeling cold all the time
• Brain fog
• Hair loss or coarse, dry hair
• Dry skin
• Heavy or irregular periods
• Swelling in the neck

What to do

The most reliable dietary sources of iodine are dairy products, seafood (particularly white fish and shellfish), and seaweed. If you have moved away from dairy and don't eat much fish, it is worth having your thyroid function tested and discussing iodine status with your GP or a registered nutritional therapist.

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The common thread

What do these five minerals have in common? They are all depleted by stress. They are all affected by the quality of the soil our food is grown in. They are all less available in processed foods than in whole foods. And they are all significantly under-tested in routine healthcare — meaning that even women who do see their GP regularly may be carrying significant deficiencies that have never been identified.

The good news is that all five are addressable — through targeted supplementation, dietary changes, and a clear understanding of what your body actually needs.

Julie Piper Roche is a Nutritional Therapist and Personal Trainer based in Ireland, and founder of The Supplement Coach. She holds a BSc (Hons) in Nutritional Therapy from the Institute for Optimum Nutrition (ION) and a Diploma in Nutritional Therapy from the IINH. The information in this article is for educational purposes only and does not constitute medical advice. Always consult your GP or a qualified healthcare practitioner before starting a supplement programme.