Minerals in Food

Unlike vitamins, which are made by plants and animals, minerals originate from the earth. They are naturally occurring elements found in soil and water and enter the food supply through plants, animals, and the environment. Eating a variety of foods from all food groups—fruits, vegetables, grains, protein foods, and dairy—is the best way to obtain essential minerals such as calcium, iron, potassium, magnesium, and zinc.

From Soil to Plant

Minerals in plant foods come directly from the soil, water, and fertilizers used during growth. Plant roots absorb dissolved minerals from the soil, and these minerals become part of the plant’s structure and function.

For example:

• Calcium is absorbed by plants and incorporated into cell walls, helping provide structure and firmness. Oranges store calcium in their fruit and peel, while leafy greens such as kale and broccoli contain calcium in their leaves. ^[1]
• Magnesium is a key component of chlorophyll, the compound that gives plants their green color and enables photosynthesis.  ^[2]
• Iron supports plant growth and metabolism.

The mineral content of plant foods depends on the soil’s mineral composition and environmental conditions during growth.

From Ocean to Seafood

Seafood is another important source of minerals because fish and shellfish obtain nutrients directly from ocean water and marine ecosystems.

For example:

• Iodine is naturally abundant in seawater and is concentrated in many marine foods (especially seaweed and saltwater fish).    ^[3]
• Zinc, selenium, and magnesium are also commonly present in marine foods.  ^{[4]  [5]}

Because oceans contain dissolved minerals, seafood is often a rich and reliable source of several essential nutrients.

From Plants to Animals

Animal foods such as beef, poultry, pork, and dairy products contain minerals because animals obtain them from:

• The plants they eat
• The water they drink
• Mineral supplements added to animal feed

These minerals are incorporated into animal tissues. For example:

• Iron is found in higher amounts in red meat
• Zinc is abundant in many animal proteins
• Calcium and phosphorus are key components of bones and dairy products

Milk provides iodine, an essential mineral for thyroid health. Some iodine comes naturally from the cow’s diet, while additional amounts may come from iodine-containing sanitizers used during dairy production.

Regional and Environmental Influences

The mineral content of foods and water can vary based on geographic location and environmental conditions.

• Iodine levels tend to be higher in coastal regions where soils and water contain more iodine, while inland areas may have lower levels.  ^[6]
• Fluoride is naturally present in some groundwater sources, leading to higher intake in certain regions. In some communities, fluoride is added to public water supplies to support dental health.  ^[7]
• Selenium content in foods also varies widely depending on soil composition. Some regions, such as parts of the United States, have selenium-rich soils, while other areas of the world have low selenium levels. As a result, plant foods grown in selenium-poor soils—and the animals that consume them—contain less selenium, which can affect overall intake in those populations.  ^[8]

These regional differences help explain why mineral intake can vary across populations.

From Earth to You

Minerals move through the food chain—from soil and water to plants, then to animals, and ultimately to humans. Unlike vitamins, minerals cannot be destroyed by heat, light, or cooking, but they can be lost during food preparation if they leach into cooking water or are removed with parts of the food.

In summary, minerals originate in the earth and enter the diet through various pathways. Choosing a wide range of whole foods helps ensure an adequate intake of essential minerals needed for health.