<h2>Practice points</h2><ul><li>Magnesium is important for normal healthy muscle contraction. Supplementation may relieve muscle cramps and spasms which occur due to deficiency</li><li>Calcium deficiency may contribute to muscle pain and spasm</li><li>Any persistent muscle pain of unknown origin should be investigated by GP</li><li>Muscle injuries usually repair relatively quickly, whereas tendons and ligaments may take weeks or months to return to normal16</li></ul><h2>Description</h2><ul><li>Cramps have been described as the sudden, uncomfortable squeezing or contraction of a muscle1</li><li>The most common causes of muscle pain are tension, stress, overuse and minor injuries. This type of pain is usually localized, affecting just a few muscles or a small part of the body2</li><li>People who exercise can experience muscle cramps and spasms3,4 due to a variety of reasons such as dehydration, electrolyte deficits, muscle overuse and fatigue, and low magnesium levels3,4,5,6</li></ul>

<h2>Primary recommendations</h2><h2>MAGNESIUM</h2>Mechanism of action<ul><li>Magnesium is essential for muscle electrical potential.5 It is required for the transport of potassium and calcium across the cell membranes, and helps effect conduction of nerve impulses and muscle contraction11,12</li><li>Magnesium is an essential cofactor for more than 300 enzymes involved in biosynthetic processes and energy metabolism5</li></ul>Characteristics<ul><li>Magnesium helps maintain healthy muscle contraction, and helps relieve muscle cramps and spasms which occur due to deficiency5,6</li><li>Magnesium deficiency may be associated with muscle weakness and cramping, and structural damage to muscle fibres.4 Signs of deficiency include muscle spasm, tremor and tetany6</li><li>Approximately 50% of magnesium in the body is distributed between muscle and soft tissue1,11</li><li>Stressors such as exercise may deplete magnesium.9 Strenuous exercise increases magnesium requirements by 10-20%10</li><li>Signs of severe magnesium deficiency include hypocalcaemia, hypokalaemia, retention of sodium, low circulating levels of parathyroid hormone (PTH), neurological and muscular symptoms (tremor, muscle spasms, tetany), loss of appetite, nausea, vomiting, and personality changes11</li><li>Good dietary sources of magnesium include legumes, wholegrain cereals, nuts, dark green leafy vegetables, cocoa, soy flour, seeds, nuts, mineral water and hard water14</li></ul>ResearchBioavailability of different forms of magnesiumA randomised, double blind placebo-controlled trial with 46 participants looked at the bioavailability of magnesium citrate, chelate and oxide. Both the chelate and citrate forms of magnesium showed greater absorption at 60 days (based on 24hr urinary excretion) versus the magnesium oxide (p± 0.033), with magnesium citrate giving greater serum magnesium concentration.13Dosage and formulationCitrate and amino acid chelate forms of magnesium have shown greater bioavailability than oxide.13 Dosage range is typically 300-600 mg/d.Adverse effectsThe most common adverse effect is diarrhoea. This is more likely at higher doses &gt;350 mg/d. Divide doses to reduce risk and maximise bioavailability.14Interactions<ul><li>Amphotericin B may cause a decrease in serum magnesium. Supplementation may be beneficial</li><li>Antiarrhythmic and antihypertensive drugs: magnesium may have an additive effect. Supplementation may be beneficial</li><li> Loop and thiazide diuretics may cause a decrease in serum magnesium. Supplementation may be beneficial</li><li>Proton pump inhibitors may decrease magnesium absorption. Supplementation may be beneficial</li><li>Warfarin: theoretically, magnesium may reduce efficacy</li></ul>

Primary

<h2>Secondary recommendations</h2><h2>CALCIUM</h2><ul><li>Calcium is required for proper muscle function including contraction and nerve conduction14 </li><li>Deficiency signs and symptoms include muscle pain and spasm14 </li><li>Good dietary sources include dairy products, fortified soy products, fish with bones (especially salmon and sardines), tofu, broccoli, collard greens, mustard greens, bok choy, and blackstrap molasses14 </li><li>Bioavailability: Several plant constituents, such as oxalic acid found in spinach and rhubarb, may inhibit calcium absorption.14,15 Phytic acid, found in seeds, may also inhibit calcium absorption15</li></ul>

Secondary

<h2>Diet and lifestyle</h2><ul><li>Healthy muscle activity and repair requires a wide range of nutrients including protein, magnesium, calcium, iron, zinc, vitamin D and B vitamins3</li><li>A balanced diet such as the Mediterranean diet offers a wide range of nutrients7</li><li>Consider stretching to relieve muscle cramping and improve flexibility8</li><li>Drink plenty of fluids while exercising8</li></ul>

Diet & lifestyle

<h2>References</h2>1. Van Nguyen. Magnesium supplementation in the reduction of muscle cramps: A systematic literature review. The Australian Journal of Pharmacy 2013; 94:80-83 2. Mayo Clinic. Symptoms: Muscle Pain. http://www.mayoclinic.org/symptoms/muscle-pain/basics/causes/sym-20050866. (Accessed 11/4/16) 3. American Dietetic Association, position of the American Dietetic Association, Dietitians of Canada, and the American College of Sports Medicine: Nutrition and Athletic Performance. J Am Diet Assoc. 2009;1-9:509-527 4. Jeunkendrup A and Gleeson M. Sport Nutrition Second Edition, United States of America: Library of Congress in publication data, 2010 5. EFSA. Scientifi c opinion on the substantiation of health claims related to magnesium and electrolyte balance (ID 238), energy-yielding metabolism (ID 240, 247, 248), neurotransmission and muscle contraction including heart muscle (ID 241, 242), cell division (ID 365), maintenance of bone (ID 239), maintenance of teeth (ID 239), blood coagulation (ID 357) and protein synthesis (ID 364) pursuant to Article 13(1) of Regulation (EC) No 1924/20061. EFSA Journal 2009; 7(9):1216. (accessed 27/11/2014) 6. Mason, P. Dietary supplements fourth edition. London: Pharmaceutical press, 2013 7. Oberg, E. ‘Wellness, lifestyle and preventive medicine’. In Sarris J and Wardle J. Clinical Naturopathy 2e, an evidence based guide to practice. Australia: Churchill Livingstone, 2014:578. US National Library of Medicine Medline Plus. Muscle Cramps. Available at https://www.nlm.nih.gov/medlineplus/musclecramps.html Accessed 16.5.16 9. Driskell, J and Wolinsky I. Nutritional concerns in recreation, exercise and sport. USA:CRC Press, 2009:133 10. Burke B and Deakin V. Clinical Sports Nutrition 4th ed. Australia: McGraw-Hill, 2010:274 11. Murray MT. Magnesium. In Encyclopaedia of Nutritional Supplements. USA: Prima Publishing, 1996:159-172 12. Higdon,J and Drake VJ. An evidence based approach to vitamins and minerals 2nd Edition. Germany, Thieme, 2012. 13. Walker AF et al. Mg citrate found more bioavailable than other Mg preparations in a randomised, double-blind study. Magnesium Research, 2003;16(3):183-191 14. Braun L, Cohen M. Herbs &amp; Natural Supplements. 4th edition. Chatswood: Elsevier, 2015 15. Weaver, CM &amp; Heaney, RP. ‘Calcium’ in Ross C et al. Modern Nutrition in Health and Disease 11th ed. Calcium. USA: Lippincott Williams &amp; Wilkins, 2014 16. Doherty, M et al. ‘Musculoskeletal disorders’. In Boon NA et al. (eds) Davidson’s Principles and Practice of Medicine 20th ed. Philadelphia: Churchill Livingstone, 2006:1065-1144

Muscle cramps

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