Magnesium is the fourth most common and abundant mineral present in the human body after calcium, potassium, and sodium. Magnesium is not synthesized by the body and hence it must be continuously refilled and replenished through diet or foods and water intake to prevent deficiency.
Functions of Magnesium
Magnesium acts as a cofactor in more than 300 enzyme systems. It is involved in regulation of various biochemical reactions including muscle and nerve transmission, protein synthesis, signal transduction, neuromuscular conduction, blood glucose control, and regulation of blood pressure. Some of the examples of magnesium-dependent enzymes are hexokinase, Na+/K+ -ATPase, protein kinase, creatine kinase, and cyclases. Another important role of magnesium is for the structural function of proteins, mitochondria, or nucleic acids. It is also required for synthesis of DNA and RNA, and for aerobic and anaerobic energy production in oxidative phosphorylation and glycolysis, indirectly as a part of magnesium-ATP complex or directly as an enzyme activator.
Magnesium also plays important role in the active transport of calcium and potassium ions across the cell membrane. It also contributes to the development of bone structure and is necessary for the adenosine-triphosphate-dependent synthesis of glutathione, important intracellular antioxidant.
More than half of the total body magnesium is stored in bone and the remaining 40% is located either extra- and intracellularly. Magnesium is considered as an important electrolyte in the human metabolism after sodium, potassium, and calcium.
Adequate intake of magnesium is associated with lower risk of diabetes, atherosclerosis, stroke, heart failure, and hypertension.
Deficiency of Magnesium
The deficiency of magnesium, i.e. hypomagnesemia is defined as the serum magnesium concentration lower than 0.75 mmol/L. The early signs of deficiency are non-specific which includes lethargy, loss of appetite, nausea, fatigue, vomiting, and weakness. Further, it might lead to symptoms such as increased neuromuscular excitability such as carpopedal spasm, tremor, muscle cramps, generalized seizures, and tetany. It can also cause cardiac arrhythmias.
The conditions which might lead to hypomagnesemia are alcoholism, malabsorption (Crohn’s disease, coeliac disease, ulcerative colitis, and short bowel syndrome), poorly-controlled diabetes, endocrine causes (hyperparathyroidism, aldosteronism, and hyperthyroidism), renal disease, and medication. Most often hypomagnesemia is associated with other electrolyte abnormalities, namely hypokalemia, and hypocalcemia.
Recommended Dietary Allowances for Magnesium
The recommended dietary allowances for magnesium are:
- 1 to 3 years: 80 mg/ day.
- 4 to 8 years: 130 mg/ day.
- 9 to 13 years: 240 mg/ day.
From 14 years onwards, the requirements are different according to gender.
- 14 to 18 years: Male-410 mg/day; female: 360 mg/day.
- Above 19 years: Male – 400-420 mg/ day; female- 310-320 mg/ day.
- Pregnancy: 350-400 mg/d day.
- Lactation: 310-360 mg/ day.
Magnesium Rich Food Sources
The best food sources of magnesium are nuts and seeds, whole grains, dark green vegetables, and legumes. It can be added to some of the breakfast cereals and fortified foods.
Let us discuss some of the high magnesium content foods.
- Whole grains: Whole grains are excellent sources of many nutrients including magnesium, such as wheat, oats, barley, and pseudocereals like buckwheat and quinoa. Whole grains are also rich in B vitamins, manganese, selenium, and fiber. 1 cup oatmeal contains 58mg of magnesium. One slice of whole wheat bread contains 23mg of magnesium.
- Nuts: The nuts are nutritious and are tasty too. The nuts which are high in magnesium content are almonds, cashew, peanuts, and Brazil nuts. The nuts are known for their anti-inflammatory properties and are also beneficial for heart and have good satiety value. One ounce of dry roasted almonds contains 80 mg of magnesium. One ounce of cashews contains 74 mg of magnesium. One-fourth cup of oil roasted peanuts contains 63 mg of magnesium.
- Seeds: The type of seeds that contain high magnesium content include flaxseeds, pumpkin seeds, sesame seeds, and chia seeds. The seeds are rich in other nutrients also such as fiber, iron, MUFA and omega-3 fatty acids. Sunflower seeds in dry roasted form provide 512 mg of magnesium from 1 cup. Similarly, 1 cup of sesame seeds contains 101mg of magnesium.
- Legumes: The family of legumes includes beans, lentils, peas, chickpeas, and soybeans. In addition to magnesium, they are also rich in many other nutrients. Legumes have a low glycemic index, hence they are involved in lowering cholesterol, improve your blood sugar levels and decrease the risk of heart problems. They are also a good source of fiber. 1 cup black-eyed peas provide 92mg and kidney beans provide 70mg of magnesium, respectively.
- Fatty fish: The type of fatty fish that are high in magnesium include salmon, halibut, and mackerel. Fishes are also good sources of potassium, B vitamins, proteins, omega-3 fatty acids, and other nutrients. 4 ounces of raw shrimp provides 48mg of magnesium. 3 ounces of cooked halibut contains 24 mg of magnesium.
- Banana: Banana is known for its potassium content which is beneficial in lowering blood pressure and reduces the risk of heart disease. But they are also a good source of magnesium. Other nutrients that banana can provide include vitamin C, vitamin B6, manganese, and fiber. One medium banana will provide you with 32 mg of magnesium.
- Green leafy vegetables: Leafy vegetables are an excellent source of many nutrients such as vitamin A, vitamin C, vitamin K, iron, manganese, and magnesium. They also contain plant compounds that are helpful in protecting the cells from damage and might reduce the risk of cancer. A half cup of boiled spinach contains 78 mg of magnesium.
- Tofu: Tofu is rich in protein content and other nutrients such as calcium, iron, manganese, and selenium. A 100 g of tofu has 53mg of magnesium. Tofu is said to protect the cell lining of the arteries and reduce the risk of stomach cancer. 1 cup soymilk contains 61mg of magnesium.
Food processing such as refining of grains tends to remove the nutrient-rich germ and bran and hence, lower the magnesium content. About 30-40% of daily magnesium is typically absorbed by the body.
Tips on increasing magnesium intakes
- You should include a variety of vegetables, fruits, whole grains, fat-free milk and milk products, and oils in your diet.
- Add on a variety of protein foods including lean meats, seafood, eggs, poultry, legumes, nuts, seeds, and soy products.
- You should limit the intake of saturated and trans fats, added sugars, and sodium.
Finally, stay within your daily requirements for calories.
Stay fit, happy, and healthy!!!