Magnesium

Why you're almost certainly not getting enough

It is possible to eat three meals a day, take a daily multivitamin, and still be running chronically low on magnesium. Not because you are careless about your diet, but because several forces in modern life conspire against it simultaneously — and most people are unaware of any of them.

The first is the food supply itself. When whole grain wheat is refined into white flour, roughly 80 per cent of its magnesium is removed. The bran and germ, where magnesium is concentrated, are discarded as the by-product of a process designed to produce a whiter, finer, longer-lasting product. The fortification that follows replaces some vitamins — notably iron and B vitamins — but magnesium is not among them. What you get in white bread, white rice, or white pasta is a fraction of the mineral content the original grain contained.

The second is sugar. For every molecule of glucose the body metabolises, magnesium is required as a cofactor. A high-sugar diet therefore increases the body's demand for magnesium at precisely the same time that it is delivering very little of it. High sugar intake also increases urinary magnesium excretion — the body simply passes more of it out.

The third, and least understood, is modern stress. Cortisol — the primary stress hormone — drives magnesium out through the kidneys. The more chronic stress you carry, the faster you deplete your magnesium reserves. And the lower your magnesium, the more reactive your nervous system becomes to stress. This is not a metaphor. It is a documented biochemical loop.

What magnesium actually does

Magnesium is not a single-purpose nutrient. It functions as a cofactor in the enzyme systems that produce ATP — the molecule that powers every cell in the body. Without adequate magnesium, energy production falters at the cellular level. This is why magnesium deficiency so often presents as fatigue that sleep does not fix.

It regulates calcium movement in nerve cells. When calcium floods into a nerve cell, the nerve fires. Magnesium moderates this — it is, in effect, the brake on your nervous system. Without it, nerves become hyperexcitable: you feel anxious, irritable, or on edge without a clear cause. Muscles cramp. Eyes twitch. The heart, which is also a muscle governed by nerve signals, can develop palpitations or irregular rhythm.

It plays a central role in insulin signalling and glucose metabolism. Magnesium-deficient individuals are significantly more likely to develop insulin resistance — a finding that has been replicated across dozens of population studies. Low magnesium and poor blood sugar control reinforce each other in the same way that low magnesium and high stress do.

Sixty per cent of the body's magnesium is stored in bone. It is a structural component of the skeleton — not an optional mineral that floats through the bloodstream but a material that the bones are actually built from. Long-term low intake is a silent contributor to poor bone density, independent of calcium.

What's robbing you

The following are the primary magnesium depleters in modern life. Most people encounter several of them daily.

Ultra-processed food and refined grains — the dominant feature of the modern diet. As above, refining removes the majority of magnesium. A diet built around bread, pasta, breakfast cereal, snack bars, and packaged ready meals is structurally low in magnesium regardless of calorie adequacy.

Sugar and fructose — both increase urinary magnesium excretion and increase the body's demand for it during metabolism. A high-sugar diet is a magnesium-depleting diet.

Alcohol — a diuretic that substantially increases magnesium excretion in urine. Regular alcohol consumption, even at moderate levels, consistently lowers magnesium status in population studies.

Chronic stress and cortisol — as above. Cortisol directly increases renal magnesium excretion. People under sustained psychological or physical stress have measurably lower magnesium levels than those who are not.

Proton pump inhibitors (PPIs) — omeprazole, lansoprazole, esomeprazole, pantoprazole. These reduce stomach acid required for magnesium absorption. Long-term use causes hypomagnesaemia in a significant proportion of patients; this is now a documented drug interaction listed in UK prescribing guidance.

Thiazide diuretics — prescribed for high blood pressure and oedema. They dramatically increase urinary magnesium loss as a side effect. Patients on long-term thiazides should have their magnesium monitored.

Caffeine — a mild diuretic that increases urinary excretion. The effect is modest compared to alcohol or diuretic medications, but is worth noting for heavy coffee drinkers.

Your top 8 food sources

The following are selected for both magnesium density and practical everyday use. All figures are per standard serving of the whole, minimally processed food.

How much you need

Standard blood tests measure serum magnesium — the magnesium floating in your blood — but this represents only about 1 per cent of total body magnesium. Serum levels can read as normal while intracellular magnesium is significantly depleted. If your symptoms suggest low magnesium and a blood test comes back normal, that result does not rule out functional deficiency.

Smart pairings — what helps and what hinders

Putting it together

The practical goal is not to count milligrams at every meal. It is to build a pattern of eating where magnesium-rich foods appear consistently — in roughly the same way that the modern diet has consistently removed them.

A tablespoon of ground flaxseed on morning oatmeal. A handful of soaked pumpkin seeds as an afternoon snack instead of a cereal bar. Spinach with dinner rather than iceberg lettuce. Black beans in a soup or stew once or twice a week. Quinoa instead of white rice when it works. Chia seeds soaked overnight for breakfast. Almonds in a bag for when hunger arrives somewhere inconvenient.

None of these are transformations. They are replacements — swapping the refined for the whole, the stripped for the intact. Done consistently, they add up to a diet that is working with your biology rather than against it.