Micronutrient of the Week: Magnesium

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Your Good Farm in-house nutritionist. Here to bring you essential information on nutrition, diet and permaculture gardening - in a bite size, easy to understand, science-backed way.

Micronutrient of the Week: Magnesium

Magnesium is one of the most critical and most depleted minerals in modern diets. It is required for hundreds of biochemical reactions that regulate energy production, nervous system function, muscle contraction, blood sugar control and bone health. Yet many people fall short without realising it.

Over the coming months, we will explore individual micronutrients through a food-first, functional lens, starting with magnesium.

What are micronutrients?

Micronutrients, including vitamins, minerals, trace elements, and phytonutrients, are required in small amounts but are essential for metabolism, hormone production, immune function, detoxification, and cellular repair. They act like a lock-and-key system, enabling thousands of biochemical reactions that support energy production, nervous system signalling, blood sugar regulation, and cellular resilience. Even a single micronutrient deficiency can impair metabolic efficiency.

Many micronutrients also function as antioxidants, protecting cells from oxidative stress, while others influence inflammation, gene expression, and mitochondrial function, which are key determinants of long-term health. Inadequate intake of these nutrients is increasingly linked to chronic disease and accelerated biological ageing.

What does nutrient density mean?

Nutrient density refers to the concentration of micronutrients in a given food. A nutrient-dense diet emphasizes foods rich in these nutrients, focusing on fresh, local, and regenerative produce, including fruits, vegetables, spices, nuts, seeds whole-animal foods, and quality dairy, with diversity as a guiding principle.

In contrast, diets high in ultra-processed foods leave the body micronutrient-deficient, promoting inflammation, metabolic dysfunction and biological ageing.

Magnesium’s role

Magnesium is involved in over 300 enzymatic reactions and supports:

• Energy production through ATP synthesis
• Nervous system regulation
• Muscle contraction and relaxation
• Blood sugar and insulin signalling
• Stress response and adrenal function
• Bone mineralisation
• Sleep quality and circadian rhythm
• Hormone production and detoxification pathways

Low magnesium status can affect multiple physiological systems simultaneously.

Why deficiency is common

Magnesium depletion is widespread due to several factors common in modern life.

Depleted soils

Intensive farming practices have reduced mineral content in soil, lowering the magnesium content of plant foods.

Chronic stress

Stress increases magnesium excretion and cellular demand.

Refined diets

Processed foods are low in magnesium, while sugar, caffeine and alcohol increase losses.

Increased physiological demand

Pregnancy, breastfeeding, intense exercise, illness and ageing increase magnesium requirements.

Common signs of low magnesium

Deficiency often presents subtly and is frequently overlooked.

• Muscle cramps, twitching or tension
• Headaches or migraines
• Poor sleep or restless legs
• Anxiety or nervous system overactivation
• Constipation
• Fatigue or reduced stress tolerance
• Sugar cravings

Serum magnesium levels may remain normal despite intracellular depletion.

Magnesium-rich foods

Food should always form the foundation of intake.

Good sources of magnesium include:

• Dark leafy greens such as spinach, silverbeet and kale
• Pumpkin and sunflower seeds
• Sea vegetables such as spirulina
• Almonds, cashews and Brazil nuts
• Avocado
• Legumes including lentils, chickpeas and black beans
• Whole grains such as quinoa, buckwheat and brown rice
• Cacao and dark chocolate at 70 per cent or higher
• Mineral-rich water

Absorption improves when magnesium-rich foods are eaten as part of a balanced, whole-food diet with adequate protein.

Supporting absorption

Magnesium status, and micronutrient status more broadly, depends on more than intake alone. How food is grown, prepared and consumed significantly affects absorption.

Food quality

Choosing fresh, locally grown produce from farmers who use regenerative practices supports higher micronutrient intake. Regenerative farming prioritises soil health, increasing mineral availability, microbial diversity and, ultimately, plant nutrient density. Healthier soil produces more nutrient-dense food.

The shorter the time between harvest and consumption, the higher the micronutrient content. Once a plant is harvested, nutrient levels begin to decline, particularly in fragile vitamins, phytonutrients and antioxidants.

Preparation

Legumes, grains, nuts and seeds naturally contain compounds such as phytates and lectins that can inhibit mineral absorption. Traditional preparation methods such as soaking, sprouting and fermenting reduce these inhibitors and improve mineral bioavailability.

Lifestyle factors

• Excess caffeine and alcohol increase magnesium loss
• Gut inflammation reduces absorption
• Poor blood sugar control increases urinary excretion
• Vitamin D and vitamin B6 support magnesium utilisation

Addressing these factors improves the effectiveness of both food and supplementation.

How to soak grains properly

Soaking grains mimics traditional food preparation.

Basic method:

1.   Rinse whole grains such as brown rice, quinoa or oats.

2.   Soak in warm water for 12 to 24 hours.

3.   Add an acidic medium to activate phytase enzymes.
Use one tablespoon of apple cider vinegar, lemon juice or whey per cup of dry grain.

4.   Drain and rinse thoroughly.

5.   Cook as usual using fresh water.

This process reduces phytate content, improves digestibility and increases the availability of minerals such as magnesium, iron and zinc. Soaking applies to grains, legumes, nuts and seeds.

Supplement forms: not all magnesium is equal

Supplementation may be useful during periods of increased demand or depletion. However, not all forms of magnesium are absorbed or utilised equally, and the choice of form should reflect the desired therapeutic outcome. Always flip the product and read the ingredient list.

• Magnesium oxide
  Poorly absorbed and primarily acts as an osmotic laxative. Generally unsuitable for correcting deficiency.
• Magnesium carbonate / gluconate
  Typically less effective than chelated forms, with lower and more variable absorption.
• Magnesium citrate
  Moderately absorbed and commonly used to support bowel regularity. Less ideal for nervous system or long-term repletion.
• Magnesium glycinate (bisglycinate)
  Highly bioavailable and well tolerated. Commonly used to support sleep quality, muscle relaxation and stress regulation.
• Magnesium malate
  Often favoured for energy production and muscle support, as malate plays a role in the Krebs cycle. May be helpful for muscle pain or fatigue.
• Magnesium threonate
  Able to cross the blood–brain barrier and may support cognitive function and neurological health.
• Topical magnesium (sprays, oils, creams)
  May assist with local muscle relaxation. Systemic absorption appears variable and less predictable.
• Epsom salt baths (magnesium sulfate)
  Magnesium has traditionally been used to support muscle relaxation and stress relief. Its benefits are thought to arise mainly from local effects on the muscles and calming the nervous system, rather than from significant systemic absorption. Magnesium baths may be a helpful complement to dietary sources and oral supplementation.

Magnesium is foundational to metabolic health, nervous system regulation and overall physiological resilience. Adequate intake supports energy production, stress tolerance and long-term healthspan, key pillars of longevity.

If there is a specific micronutrient you would like us to explore in future articles, we would love to hear from you. Please share your suggestions or feedback in the comments below.

Disclaimer

This article is for general educational purposes only and does not replace personalised medical or nutritional advice. Individual requirements vary depending on health status, life stage and medication use. Consult a qualified healthcare practitioner before supplementing, particularly during pregnancy, breastfeeding or when managing a medical condition.

References and Further Reading

1.   Institute of Medicine (US).
Dietary Reference Intakes for Calcium and Vitamin D. National Academies Press, 2011.

2.   Rosique-Esteban, N., et al.
“Dietary Magnesium Intake Is Associated with Reduced Risk of Metabolic Syndrome.”
Journal of Nutrition, 2018.

3.   Volpe, S. L.
“Magnesium in Disease Prevention and Overall Health.”
Advances in Nutrition, 2013.

4.   de Baaij, J. H. F., et al.
“Magnesium in Man: Implications for Health and Disease.”
Physiological Reviews, 2015.

5.   DiNicolantonio, J. J., et al.
“Subclinical Magnesium Deficiency: A Principal Driver of Cardiovascular Disease and a Public Health Crisis.”
Open Heart, 2018.

6.   Lynch, B. J., & Wharton, C. M.
“Magnesium Intake and Health Outcomes.”
Nutrition Reviews, 2021.

7.   Cordain, L.
The Paleo Diet. Wiley, 2010.

8.   Montgomery, D. R.
Dirt: The Erosion of Civilizations. University of California Press, 2012.

9.   Lal, R.
“Regenerative Agriculture for Food and Climate.”
Journal of Soil and Water Conservation, 2020.

10.        Welch, R. M., & Graham, R. D.
“Breeding Crops for Enhanced Micronutrient Content.”
Food and Nutrition Bulletin, 2004.

11.        Foster-Powell, K., Holt, S. H. A., & Brand-Miller, J. C.
“International Table of Glycemic Index and Glycemic Load Values.”
American Journal of Clinical Nutrition, 2002.

12.        Hurrell, R. F., & Egli, I.
“Iron Bioavailability and Dietary Reference Values.”
American Journal of Clinical Nutrition, 2010.

13.        Reddy, N. R., et al.
“Effect of Food Processing on Reduction of Phytates.”
Food Science and Nutrition, 1982.

14.        Gibson, R. S., et al.
“Strategies to Combat Zinc Deficiency through Diet.”
Nutrition Research Reviews, 2018.

15.        National Health and Medical Research Council (NHMRC).
Nutrient Reference Values for Australia and New Zealand.