Dietary minerals are inorganic elements, originating from the earth, which are required by the body for a wide range of biological functions. Unlike vitamins, minerals do not provide energy directly but act as structural components and regulators of cellular processes. They play roles in nerve transmission, muscle contraction, maintaining fluid balance, and building skeletal tissue. Since the human body cannot produce these elements, they must be consistently obtained through the consumption of foods and beverages.
Primary Sources of Major Minerals
Major minerals, or macrominerals, are those the body requires in amounts greater than 100 milligrams per day. Calcium is the most abundant mineral, known for building strong bones and teeth, and is sourced extensively from dairy products like milk, yogurt, and cheese. For individuals avoiding dairy, alternatives include fortified tofu, canned fish eaten with the bones, and leafy green vegetables.
Potassium and sodium are electrolytes that work together to maintain fluid balance, nerve transmission, and muscle contraction. Potassium is widely found in fresh fruits and vegetables, including bananas, potatoes, melons, and legumes. Sodium is primarily obtained through common table salt and processed foods.
Magnesium is involved in numerous biochemical reactions, including protein synthesis and nerve function. It is readily available in:
- Nuts and seeds
- Whole grains
- Legumes
- Dark leafy greens
Phosphorus, another structural mineral found in bones and cell membranes, is supplied by protein-rich foods like meat, fish, poultry, eggs, and milk.
Essential Sources of Trace Minerals
Trace minerals, or microminerals, are equally important but needed in much smaller quantities, typically less than 100 milligrams daily. Iron is necessary for oxygen transport as a component of hemoglobin in red blood cells. It is found in high concentrations in organ meats, red meats, and shellfish. Plant-based sources include legumes, dried fruits, and dark leafy greens, which are often fortified in cereals and breads.
Zinc supports immune function, wound healing, and DNA synthesis, concentrated in shellfish like oysters, beef, and pumpkin seeds. Iodine is required for the production of thyroid hormones, primarily sourced from seafood, seaweed, and iodized salt. Selenium acts as an antioxidant and is found in grains, meat, and seafood, with Brazil nuts being a dense source. Copper aids in iron metabolism and energy production, available in organ meats, nuts, seeds, and whole grains.
Maximizing Mineral Absorption
Obtaining minerals from food is only the first step; the body must also efficiently absorb them, a process called bioavailability. Certain food components can inhibit mineral uptake, such as phytates found in whole grains and legumes, and oxalates present in foods like spinach and rhubarb, which bind to minerals like calcium and iron. Tannins in tea and coffee can also interfere with the absorption of iron.
Conversely, some nutrients enhance mineral absorption. Vitamin C significantly improves the absorption of non-heme iron (the form found in plant-based foods) by converting it into a more readily absorbable state. Vitamin D is essential for maximizing the body’s ability to absorb calcium and phosphorus to support bone health. Consuming mineral-rich foods alongside these enhancing vitamins improves the body’s utilization of the nutrient.
When to Consider Mineral Supplements
A balanced and varied diet is sufficient to meet mineral requirements for most healthy adults. However, certain life stages or dietary restrictions can increase the risk of specific deficiencies, making supplementation a practical consideration. Women who are pregnant or planning to conceive often require extra iron and folic acid, and those with heavy menstrual periods may benefit from an iron supplement.
Individuals following strict diets, such as vegans, may need to supplement minerals like iron, zinc, and iodine, as these are often more bioavailable or abundant in animal products. People with malabsorption disorders, such as celiac disease, or those recovering from gastric bypass surgery, may also struggle to absorb sufficient minerals from food alone. High-dose supplements should only be taken under the guidance of a healthcare professional, as excessive intake can lead to toxicity.