Minerals in food are inorganic nutrients your body needs but cannot produce on its own. They serve as building materials for bones, help regulate fluid balance, support muscle and nerve function, and act as components of hormones and enzymes. Unlike vitamins, minerals hold their chemical structure through cooking and digestion, though how much your body actually absorbs depends on several factors.
Two Categories: Macrominerals and Trace Minerals
Dietary minerals split into two groups based on how much your body requires each day. Macrominerals are needed in larger amounts, typically hundreds of milligrams. Trace minerals are needed in much smaller quantities, sometimes just micrograms.
The seven macrominerals are calcium, phosphorus, magnesium, sodium, potassium, chloride, and sulfur. The trace minerals include iron, zinc, selenium, iodine, copper, manganese, fluoride, and cobalt. Both groups are equally important for health. “Trace” refers only to the quantity needed, not to significance.
What Each Major Mineral Does
Calcium is the mineral most people associate with bones, and for good reason. Combined with phosphorus, it forms hydroxyapatite, the hard structural material in bones and tooth enamel. About 85% of the phosphorus in your body sits in your bones and teeth, with the remaining 15% spread through blood and soft tissues, where it helps store energy, build cell membranes, and regulate how genes are read. Dairy products, meats, poultry, fish, eggs, nuts, legumes, and grains all supply phosphorus.
Magnesium supports hundreds of enzyme reactions and plays a role in blood pressure regulation, blood sugar control, and bone density. Good sources include nuts, seeds, whole grains, and leafy greens.
Electrolyte Minerals
Sodium, potassium, and chloride function as electrolytes, controlling the movement of water in and out of your cells. Sodium is the dominant electrolyte outside your cells, determining the volume and pressure of that fluid. Potassium is the dominant electrolyte inside your cells, where it maintains membrane stability and acid-base balance.
Most dietary sodium comes paired with chloride as table salt, and it’s concentrated in bread, grains, meat products, and condiments. Potassium sources are more varied: fruits, vegetables, and legumes supply about 26% of the average person’s potassium intake, with milk products, meat, coffee, and potatoes each contributing meaningful amounts as well.
Key Trace Minerals and Their Food Sources
Iron is essential for carrying oxygen in your blood. It exists in two dietary forms: heme iron from animal foods and non-heme iron from plants. About 25% of heme iron gets absorbed from a meal, compared to 17% or less for non-heme iron. Red meat, poultry (especially darker cuts like thighs and drumsticks), fish, and shellfish are rich in heme iron. Plant sources of non-heme iron include legumes, dark leafy greens, nuts, seeds, whole grains, and dried fruits.
Zinc supports immune function, wound healing, and your senses of taste and smell. It’s found in meat, shellfish, legumes, nuts, and seeds. Selenium, concentrated in Brazil nuts, seafood, and organ meats, helps protect cells from damage and supports thyroid function.
Iodine is needed to produce thyroid hormones, which regulate metabolism and are critical for brain development in fetuses and infants. Seaweed is one of the richest food sources. Three ounces of baked cod provides about 146 micrograms, a cup of nonfat milk supplies around 84 micrograms, and a quarter teaspoon of iodized table salt delivers roughly 78 micrograms. Dairy, eggs, and seafood round out the main sources.
What Affects How Well You Absorb Minerals
Eating a mineral-rich food doesn’t guarantee your body takes it all in. Several compounds in food can block absorption, and a few can enhance it.
Phytates, the stored form of phosphorus found in seeds, nuts, legumes, and the outer bran of whole grains, bind to iron, zinc, magnesium, and calcium in the gut, carrying them out before they can be absorbed. One review found that phytates reduced non-heme iron absorption to anywhere between 1% and 23%, a wide range depending on the meal. Oxalates, found in spinach, Swiss chard, beets, almonds, and potatoes, bind specifically to calcium and prevent it from being absorbed. This is why spinach, despite its high calcium content on paper, is not actually a great calcium source for your body.
On the enhancer side, vitamin C is the only dietary factor besides animal tissue shown to promote iron absorption. It works by creating a more acidic environment in the stomach, keeping iron in a form that intestinal cells can take up. Pairing a squeeze of lemon juice or bell peppers with a bean dish is a practical example. That said, the effect is strongest when tested with a single meal in isolation. Across a full day’s diet, the boost is less dramatic.
Eating calcium-rich foods alongside oxalate-rich foods can also be strategic: the oxalates bind to calcium in the stomach before reaching the intestine, which reduces oxalate absorption into the bloodstream. This is more relevant for people concerned about kidney stones than for maximizing calcium intake.
How Cooking Changes Mineral Content
Minerals are chemically stable, so heat itself doesn’t destroy them. The issue is water. Boiling, stewing, and braising allow minerals to leach out of food and into the cooking liquid. Dry-heat methods and shorter cooking times preserve more of the original mineral content.
Steaming retains minerals far better than boiling. Studies on zucchini, for example, showed mineral retention rates between 78% and 118% with steaming, meaning most minerals stayed in the food. Potatoes are more vulnerable because they’re typically peeled and cut into pieces before cooking, increasing the surface area exposed to water. Shredding potatoes before boiling reduced potassium and other minerals by about 75%, while cubing them before boiling caused a 45% loss. Cooking potatoes with the skin on and in larger pieces limits this significantly.
Grain refining also strips minerals. When whole grains are processed into white flour, the mineral-dense bran and germ are removed. This is why whole grain bread, brown rice, and other minimally processed grains deliver more magnesium, zinc, and iron than their refined counterparts.
Signs You’re Not Getting Enough
Iron deficiency is the most common mineral deficiency worldwide. Symptoms include persistent fatigue, pale skin, weakness, shortness of breath during activity, and poor tolerance of cold temperatures. People who menstruate, pregnant individuals, and those on exclusively plant-based diets are at higher risk.
Zinc deficiency can show up as slow wound healing, frequent infections, reduced sense of taste or smell, hair loss, poor appetite, and skin lesions. It’s more common in people who eat little meat or shellfish, and in those whose diets are heavy in phytate-rich grains and legumes without strategies to improve absorption.
Low magnesium over time is linked to high blood pressure, weakened bones, and impaired blood sugar regulation. Because magnesium is widespread in foods like nuts, seeds, and whole grains, deficiency tends to reflect an overall dietary pattern rather than a single missing food.
Can You Get Too Much?
Getting excessive minerals from food alone is rare for most people. The risk increases with supplements. The Food and Nutrition Board has set tolerable upper intake levels for adults: 2,500 mg per day for calcium, 45 mg for iron, 40 mg for zinc, 1,100 micrograms for iodine, and 400 micrograms for selenium. For magnesium, the upper limit of 350 mg applies only to supplements, not to magnesium from food and water.
Too much iron can cause nausea and organ damage over time. Excess calcium from supplements has been associated with kidney stones. Selenium toxicity, though uncommon, can cause hair loss, brittle nails, and neurological symptoms. These thresholds are difficult to exceed through diet alone, which is one reason whole foods are generally a safer source of minerals than high-dose supplements.