Micronutrients You Might Not Be Getting Enough Of

Vitamin D supports calcium absorption, bone density, immune function, and mood regulation. The body can synthesize it from sun exposure, but many Americans — particularly those in northern states, people who work indoors, and individuals with darker skin tones — don't produce adequate amounts year-round.

Dietary sources are limited but include fatty fish (salmon, mackerel, sardines), egg yolks, and fortified foods such as milk and some orange juices. Because food sources alone are often insufficient, vitamin D is one of the nutrients a doctor may specifically test for and recommend supplementing — but dosage should be guided by a professional, not assumed.

Magnesium participates in more than 300 enzymatic reactions in the body, including those governing muscle contraction, blood sugar regulation, and protein synthesis. Despite this, surveys suggest a significant portion of Americans consume less than the recommended amount.

Magnesium is found in leafy green vegetables (spinach, Swiss chard), legumes, nuts and seeds (especially pumpkin seeds and almonds), whole grains, and dark chocolate. Heavily processed diets that displace these foods tend to be lower in magnesium. Getting more variety from plant-based whole foods is often enough to improve intake meaningfully.

Potassium helps regulate fluid balance, nerve signals, and muscle contractions, including the heartbeat. It also plays a role in counteracting the blood-pressure-raising effects of sodium — relevant given that most Americans consume significantly more sodium than potassium.

Bananas are the food most people associate with potassium, but they're far from the richest source. Beans, lentils, potatoes (especially with the skin), avocados, leafy greens, and dairy products all provide substantial amounts. Shifting toward a diet with more whole plant foods naturally moves potassium intake in the right direction.

Calcium is best known for bone and tooth health, but it also supports muscle function and nerve transmission. While dairy is the most widely recognized source, it's not the only one — and those who avoid dairy may miss this nutrient entirely without deliberate planning.

Good non-dairy sources include fortified plant milks, canned fish with edible bones (sardines, salmon), tofu made with calcium sulfate, almonds, chia seeds, and dark leafy greens like kale and bok choy. Note that some leafy greens (notably spinach) contain oxalates that reduce calcium absorption, so variety matters here too.

Vitamin B12 is essential for red blood cell production, neurological function, and DNA synthesis. It's found almost exclusively in animal products, which puts people following vegetarian or vegan diets at meaningful risk for deficiency. Older adults are also vulnerable because the stomach's ability to absorb B12 from food decreases with age.

Reliable sources include meat, poultry, fish, eggs, and dairy. For those avoiding animal products, fortified foods — certain plant milks, breakfast cereals, and nutritional yeast — are the primary dietary options. Supplementation is often recommended for vegans and older adults; a healthcare provider can assess what's appropriate.

Iron is central to the production of hemoglobin, the protein in red blood cells that carries oxygen. Iron-deficiency anemia is one of the most common nutritional deficiencies worldwide, disproportionately affecting women of childbearing age and people who eat little or no meat.

There are two forms: heme iron (from animal sources, absorbed more efficiently) and non-heme iron (from plant sources). Red meat, poultry, and seafood provide heme iron. Legumes, tofu, fortified cereals, pumpkin seeds, and dark leafy greens provide non-heme iron. Eating non-heme iron sources alongside vitamin C-rich foods meaningfully improves absorption — for example, adding bell pepper or citrus to a bean dish.

Iodine is necessary for thyroid hormone production, which governs metabolism, growth, and development. While iodine deficiency is less common in the U.S. than in some parts of the world — largely because iodized table salt became widespread — it remains a concern, particularly as people shift away from table salt toward sea salt or specialty salts (which are often not iodized).

Seafood and dairy are among the most reliable food sources. Eggs and some grains also contribute. People who follow plant-based diets and use non-iodized salt should pay particular attention to this nutrient. Seaweed contains iodine but in highly variable amounts, making it an unreliable sole source.