Overlooked Gaps: Micronutrients Many Americans Tend to Under-Consume

Vitamin D supports calcium absorption, bone density, immune function, and muscle health. Despite its importance, the majority of Americans don't get enough — a pattern driven largely by limited sun exposure (especially in northern states during winter) and a food supply that doesn't naturally contain high amounts of it.

Food sources: Fatty fish such as salmon, tuna, and sardines are among the best natural sources. Egg yolks and beef liver contribute smaller amounts. Most Americans get vitamin D primarily through fortified foods — including cow's milk, many plant-based milks, and some orange juices and breakfast cereals.

People with darker skin tones, those who spend most of their time indoors, and older adults are at elevated risk for low vitamin D levels and may benefit from discussing supplementation with a healthcare provider.

Calcium is essential for bone structure, muscle contraction, nerve signaling, and blood clotting. It is the most abundant mineral in the human body, yet surveys indicate many Americans — particularly women, adolescents, and older adults — consume less than recommended amounts.

Food sources: Dairy products (milk, yogurt, cheese) are the most concentrated sources in the American diet. Non-dairy options include calcium-set tofu, canned fish with soft bones (like sardines or salmon), white beans, and fortified plant-based milks. Leafy greens such as bok choy, kale, and broccoli provide calcium, though some greens like spinach contain compounds called oxalates that reduce absorption.

Calcium and vitamin D work in tandem — adequate vitamin D is needed for the body to absorb calcium effectively, making both nutrients worth addressing together.

Potassium is an electrolyte that helps regulate blood pressure, supports fluid balance, and is needed for normal heart and muscle function. Federal dietary guidelines consistently identify potassium as a nutrient of public health concern due to widespread under-consumption.

Food sources: Potassium is broadly present in whole plant foods. Bananas are well-known sources, but they're far from the only option — sweet potatoes, white potatoes (with skin), white beans, lentils, avocados, winter squash, spinach, and tomato products are all rich sources. Many Americans under-consume potassium largely because they eat relatively little produce and legumes overall.

High-sodium, low-potassium diets are associated with greater cardiovascular risk. Shifting the balance by eating more potassium-rich whole foods — rather than focusing solely on reducing sodium — is a practical strategy supported by dietary research.

Magnesium participates in more than 300 enzymatic reactions, including energy production, protein synthesis, blood sugar regulation, and nerve function. It also plays a role in bone health. Despite its central importance, about half of Americans consume less magnesium than recommended, according to national nutrition data.

Food sources: Nuts and seeds — particularly pumpkin seeds, almonds, cashews, and peanuts — are excellent sources. Legumes, whole grains (such as quinoa and brown rice), dark leafy greens, and dark chocolate also contribute meaningful amounts. Refined grain products lose a significant portion of magnesium during processing, which helps explain why diets heavy in white bread and processed foods tend to run low.

Iron is essential for producing hemoglobin, the protein in red blood cells that carries oxygen throughout the body. Iron deficiency is the most common micronutrient deficiency worldwide, and certain American populations — including women of childbearing age, pregnant women, young children, and frequent blood donors — face the greatest risk.

Food sources: Iron comes in two forms. Heme iron, found in red meat, poultry, and seafood, is absorbed more readily by the body. Non-heme iron is found in plant foods such as lentils, kidney beans, tofu, fortified cereals, and spinach, but is absorbed less efficiently. Pairing non-heme iron sources with foods high in vitamin C — such as bell peppers, citrus, or tomatoes — can significantly enhance absorption.

Pregnant individuals have substantially higher iron needs and should discuss requirements with their obstetric care provider rather than self-supplementing.

Vitamin A is a fat-soluble vitamin that supports vision (especially in low light), immune function, and skin and cell health. While outright vitamin A deficiency is rare in the United States, national surveys suggest that many Americans consume less than optimal amounts, particularly from plant-based precursor forms.

Food sources: Preformed vitamin A (retinol) is found in animal products — liver, dairy, and eggs. Plant foods provide beta-carotene and other carotenoids, which the body converts to vitamin A. Orange and yellow vegetables (carrots, sweet potatoes, winter squash) and dark leafy greens (kale, spinach, collard greens) are among the richest plant-based sources. Because vitamin A is fat-soluble, consuming carotenoid-rich foods alongside a small amount of dietary fat improves absorption.