Three minerals—calcium, phosphorus, and magnesium—account for 98% of the body’s mineral content by weight. Calcium and phosphorus play basic roles in countless biochemical reactions at the cellular level. They are also the main components of the skeleton, and without magnesium many metabolic functions could not take place.
Phosphorus is in almost all animal and vegetable foods and is often found in foods that contain calcium. Milk and dairy products, fish bones (such as in canned salmon and sardines), and dark-green, leafy vegetables are the best sources of calcium. Magnesium, like phosphorus, is abundant in animal and plant cells.
Healthy children do not lack phosphorus and magnesium because these minerals are easily absorbed. By contrast, low calcium intakes are very common, especially among adolescent girls who shun milk and dairy foods to avoid fat calories. These girls risk osteoporosis, or thinning of the bones, starting as early as age 30. Nonfat milk, yogurt, and other dairy foods are excellent sources of calcium and do not add unwanted fat calories to the diet.
Mineral absorption is influenced by a number of factors, including certain hormones and vitamin levels. Infants absorb calcium more easily than adults do, and the rate of absorption is increased when other nutrients are around, including the milk sugar lactose, the amino acids lysine and arginine, and vitamin C (eg, calcium-fortified orange juice). Calcium absorption may be decreased by high dietary levels of phosphate, oxalate (in rhubarb and certain leafy green vegetables), or phytate compounds in fiber. Too much protein in the diet may increase the amount of calcium excreted in the urine and decrease the amount available for building bones.
Although we often hear about the importance of minerals like calcium, potassium, and foods high in iron, magnesium is frequently omitted from the conversation, yet it is a key mineral involved in numerous functions in the body. Magnesium plays an integral role in over 300 different enzymatic reactions in the body, with functions spanning the gamut from protein synthesis and blood sugar regulation to controlling blood pressure and conducting nerve and muscle impulses. It forms a major structural component of bones and teeth and acts as an electrolyte, helping transport calcium and potassium ions across cell membranes, which is necessary to maintain a heartbeat, nerve impulses, and muscle contractions.
Unfortunately, national data shows that nearly 50% of adults in the United States do not meet the recommended daily allowance (RDA) of magnesium, which is between 400-420 mg for men, depending on age. Endurance athletes are particularly prone to magnesium deficiencies due to the excess loss of magnesium in sweat, so if you work out a lot, your magnesium needs may be even higher. The good news is that there are plenty of healthy foods high in magnesium.
Regularly consuming foods high in magnesium can help ensure your body has a plentiful supply of this vital mineral. Keep reading for a list of the foods highest in magnesium and make room on your shopping list for a few of your favorites.
Nuts certainly have earned their well-deserved reputation of being nutritious superfoods, due to their rich content of many essential nutrients like omega-3 fatty acids and vitamin E. They are also good sources of magnesium. Brazil nuts are particularly high in magnesium, with 25% of the recommended daily allowance in a single ounce. Brazil nuts may be less popular than fan favorites like walnuts, but they have a delightfully creamy texture and mild flavor. Almonds and cashews also provide nearly 20% of the daily value of magnesium, and they are high in melatonin, so they may help you sleep at night.
Avocados, which are technically a fruit, are packed with vitamin E and the heart-healthy monounsaturated fats that help make the Mediterranean Diet so effective at reducing the risk of various lifestyle diseases. An avocado contains about 60mg of magnesium or 15% of the recommended daily allowance. Try adding avocados to salads, sandwiches, omelets, or even smoothies. They add a lush creaminess and provide plenty of satiety because of their fat and fiber.
Several whole grains are high in magnesium. Brown rice and buckwheat, for example, provide 86mg per cup, which is 20% of the recommended daily allowance. They also provide sustaining complex carbohydrates, B vitamins, and some fiber. Quinoa, which is usually grouped with whole grains but is actually a seed, is also packed with magnesium. One cup of cooked quinoa has nearly 30% of the RDA.
Lima beans are slightly sweet, starchy, rich legumes that work well with salads, succotash, and healthy soups. They are quite high in magnesium. One cup of cooked lima beans contains 126mg of magnesium, which is 30% of the recommended daily allowance. Other legumes are also good sources of magnesium. White beans have nearly as much magnesium as lima beans and are also one of the best dietary sources of potassium. Black-eyes peas, kidney beans, chickpeas, and lentils are rich in magnesium. Legumes are also packed with fiber, B vitamins, complex carbohydrates, and antioxidants.
Tofu is a great plant-based source of protein for vegans and vegetarians. It’s also rich in nutrients like calcium, selenium, iron, and manganese. It also contains healthy phytonutrients and antioxidants shown to support prostate health. Tofu is also quite high in magnesium. One cup of firm tofu has 146mg of magnesium, which is an impressive 35% of the recommended daily allowance. Moreover, the absorption of magnesium is enhanced when consumed with protein, so tofu may be one of the best dietary sources of magnesium.
Tuna and other fatty fish are among the best dietary sources of omega-3 fatty acids, which reduce inflammation in the body and support cardiovascular and brain function. They also provide vitamin D, a steroid hormone that is crucial for bone health and mood regulation. Tuna also happens to be a good source of magnesium. A 6-ounce fillet provides 109mg (26% of the RDA). Mackerel and pollock are also good sources of magnesium, and since fish is high in protein, magnesium absorption is enhanced in any of these options.
Spinach and other dark leafy green vegetables hit nearly all of the marks when it comes to nutrient content, which is why they are considered to be among the healthiest vegetables. Dark leafy greens contain water, fiber, B vitamins, vitamins A and K, iron, calcium, and yes, magnesium. One cup of cooked spinach contains an impressive 157mg of magnesium, which is nearly 40% of the recommended daily allowance. Swiss chard is right up there with 36% of the RDA in the same-sized serving. Kale, collard greens, and turnip greens are also high in magnesium.
Pumpkin and Squash Seeds
Squash and pumpkin seeds are some of the best sources of zinc, among other key nutrients like omega-3 fatty acids, foods high in biotin, and antioxidants. One ounce of either pumpkin seeds or squash seeds contains 156mg of magnesium (37% RDA). Flax seeds and chia seeds are also high in magnesium, but hemp seeds actually top the chart, with a whopping 47% of the RDA in a single ounce. Consider using hemp protein powder in protein shakes or homemade protein balls.
Bananas may be most heralded for their high potassium content, but they also contain vitamin C and prebiotic fiber, which feeds your beneficial gut bacteria. One medium banana has about 40mg of magnesium, so consider having a banana as a pre-workout snack to give your body the electrolytes you need in case you work up a heavy sweat.
Non-fat or low-fat yogurt is a good source of magnesium. One cup has about 47mg. Yogurt is also a good source of zinc, an essential mineral that supports your immune system. Dairy products also can help you sleep well at night, as they provide melatonin and tryptophan, an amino acid that can encourage sleepiness.
Who doesn’t want another reason to enjoy some dark chocolate? You’re in luck. Not only is dark chocolate an excellent source of antioxidants, but it also is high in magnesium. A one-ounce serving of dark chocolate has 65mg (15% RDA) of magnesium.
Calcium and Lactose in Common Foods
|Calcium Content||Lactose Content|
|Soymilk, fortified, 1 cup||200–300 mg||0|
|Sardines, with edible bones, 3 oz.||270 mg||0|
|Salmon, canned, with edible bones, 3 oz.||205 mg||0|
|Broccoli, raw, 1 cup||90 mg||0|
|Orange, 1 medium||50 mg||0|
|Pinto beans, 1/2 cup||40 mg||0|
|Tuna, canned, 3 oz.||10 mg||0|
|Lettuce greens, 1/2 cup||10 mg||0|
|Yogurt, plain, low-fat, 1 cup||415 mg||5g|
|Milk, reduced fat, 1 cup||295 mg||11g|
|Swiss cheese, 1 oz.||270 mg||1g|
|Ice cream, 1/2 cup||85 mg||6g|
|Cottage cheese, 1/2 cup||75 mg||2-3g|
Calcium is absorbed and used only when there is enough vitamin D in the body. A balanced diet should provide an adequate supply of vitamin D from sources such as eggs and liver. Sunlight also helps the body naturally absorb vitamin D, and with enough exposure to the sun, food sources may not be necessary.
Some people with lactose intolerance may think they are not getting enough calcium and vitamin D in their diet. Consultation with a doctor or dietitian may be helpful in deciding whether dietary supplements are needed. Taking vitamins or minerals of the wrong kind or in the wrong amounts can be harmful. A dietitian can help plan meals that will provide the most nutrients with the least chance of causing discomfort.