Magnesium is involved in over 300 biochemical reactions — more than any other mineral — and studies suggest that up to 70% of adults don't consume the recommended amount. This widespread insufficiency has consequences that range from the common (muscle cramps, poor sleep, headaches) to the clinically significant (hypertension, insulin resistance, increased cardiovascular risk), yet it receives a fraction of the attention given to vitamin D or iron deficiency.
What Magnesium Does
Magnesium's functions span virtually every major biological system. It's an essential cofactor for ATP synthesis — the process by which cells produce energy — meaning that magnesium deficiency impairs energy production at a cellular level before any symptoms are apparent. It regulates calcium movement into muscle cells, which is how it controls muscle contraction and relaxation. It supports nerve signal transmission, blood glucose regulation, blood pressure through its vasodilatory effects on blood vessel walls, and protein synthesis. It's required for vitamin D activation — without adequate magnesium, vitamin D cannot be converted into its active form regardless of supplementation. And it's a cofactor for GABA synthesis — the inhibitory neurotransmitter that promotes calm and supports sleep.
Signs of Magnesium Insufficiency
Severe magnesium deficiency is relatively rare in otherwise healthy people. Mild-to-moderate insufficiency — which population surveys suggest is common — produces subtler signs that are easily attributed to other causes: persistent muscle tension and cramps (particularly leg cramps at night), difficulty sleeping and staying asleep, increased anxiety or irritability, migraines and tension headaches, fatigue, and constipation. Many people address these symptoms individually (sleep aids, muscle creams, headache medication) without considering magnesium status as a contributing factor.
Food Sources
The richest dietary sources of magnesium include: dark chocolate (70%+ cocoa — approximately 65mg per 28g serving), pumpkin seeds (approximately 150mg per 30g — one of the single best sources per serving), spinach (approximately 78mg per 100g cooked), black beans (approximately 60mg per 100g cooked), quinoa (approximately 64mg per 100g cooked), almonds (approximately 76mg per 30g), avocado (approximately 29mg per half), whole grains, and oily fish. The UK recommended intake is 300mg for men and 270mg for women — achievable through diet but easily missed when the diet is low in vegetables, legumes, and whole grains.
Processing reduces magnesium content significantly. White bread provides approximately 25mg per 100g versus 80mg in whole grain bread. Refined cereals provide less than half the magnesium of the whole grain they're made from. This is one reason that the shift toward ultra-processed food consumption has coincided with reduced population magnesium intake.
Supplementation
Magnesium supplementation is among the safest and best-evidenced supplement interventions for several common complaints. The form matters: magnesium oxide is cheap and widely available but poorly absorbed. Magnesium glycinate (or bisglycinate) is the best-tolerated and best-absorbed form for general use. Magnesium threonate specifically has evidence for crossing the blood-brain barrier and may be particularly relevant for cognitive and sleep applications. Magnesium citrate is intermediate in absorption and also has a gentle laxative effect — useful for constipation, less so for those without it. A dose of 200–400mg in the evening is the most common approach, and for sleep quality in particular, taking it before bed has the strongest evidence base.
Get These Nutrients Through Vanda's Kitchen
Understanding magnesium deficiency is the first step. The practical next step is ensuring your daily diet actually delivers the nutrients your body needs. For City of London workers, Vanda's Kitchen's freshly prepared Filipino-inspired lunch provides a genuinely nutritious alternative to the processed options that dominate the EC4 lunch scene. Our food is built around lean proteins, fresh vegetables, and complex carbohydrates — a natural source of the nutrients that magnesium deficiency research identifies as important.
Our certified halal, 100% nut-free kitchen near St Paul's Cathedral delivers to offices across the City. Every item is freshly prepared and fully allergen-labelled. For a genuinely nutritious working lunch, see our healthy office lunch delivery guide and view our team lunch options.
For related reading, see zinc and immunity guide and vitamin D deficiency guide. WhatsApp us or order for your team today.
Fresh, Nutritious Food at Vanda's Kitchen
Vanda's Kitchen near St Paul's Cathedral EC4 provides one of the most nutritionally complete and allergen-safe food options in the City of London. Our Filipino-inspired menu is built around lean proteins, fresh vegetables, and complex carbohydrates — the nutritional combination that supports sustained energy, cognitive performance, and the various health outcomes covered in this article. Our food is certified halal, prepared in a 100% nut-free kitchen, and fully allergen-labelled, making it appropriate for the broadest range of dietary requirements in London's diverse workforce.
For City professionals who want genuinely nutritious daily lunches without leaving the office, our Freedom Tray delivery service provides fresh, labelled food to your desk from our EC4 kitchen. Our Selfridges Food Hall presence confirms the quality standard we maintain. To order for your team or to discuss corporate delivery, view our team lunch options, WhatsApp us, or send an enquiry. Read our healthy office lunch delivery guide for more on what we offer.