Micronutrients: The Vitamins and Minerals Most Young Adults Fall Short On

Vitamin D plays a central role in calcium absorption, immune function, and mood regulation. Despite its importance, it is one of the most widespread deficiencies in the US, particularly among people who spend most of their time indoors, have darker skin tones, or live at higher latitudes where sun exposure is limited.

The body produces vitamin D when skin is exposed to UVB sunlight, but dietary sources matter too. Fatty fish (such as salmon and sardines), egg yolks, and fortified foods like dairy and some plant-based milks all contribute. If sun exposure is consistently low, a healthcare provider may recommend a supplement after testing blood levels.

Iron is essential for producing hemoglobin, the protein in red blood cells that carries oxygen throughout your body. Low iron can cause fatigue, difficulty concentrating, and weakened immune response. Young women who menstruate are at higher risk due to monthly blood loss, but iron shortfalls affect men too, particularly those eating little or no meat.

There are two types: heme iron (found in animal products like beef, chicken, and fish) and non-heme iron (found in legumes, tofu, fortified cereals, and dark leafy greens). Non-heme iron is less readily absorbed, but consuming it alongside a vitamin C source — such as bell peppers, citrus, or tomatoes — can meaningfully improve uptake. For more on how nutrients interact, see our macronutrients explainer.

Magnesium is involved in over 300 enzymatic reactions in the body, including energy production, muscle function, nerve transmission, and blood sugar regulation. Despite this, national dietary surveys consistently show that a large share of Americans do not meet recommended intakes.

Refined and processed foods — which make up a significant portion of many young adults' diets — are stripped of magnesium during processing. Reliable food sources include pumpkin seeds, almonds, black beans, whole grains, and dark chocolate. Since magnesium is found predominantly in plant foods, increasing vegetable and legume intake is a straightforward way to raise levels naturally.

Calcium is the most abundant mineral in the human body and is critical for building and maintaining bone density — a process that peaks in early adulthood. Getting enough calcium during your twenties is an investment in long-term skeletal health, since bone mass accumulated in these years helps reduce fracture risk later in life.

Dairy products are well-known sources, but calcium is also found in fortified plant milks, tofu made with calcium sulfate, canned fish with soft bones (like sardines), and leafy greens such as kale and bok choy. Note that spinach contains calcium but also oxalates, which limit how much the body can absorb — variety across sources is helpful.

Potassium helps regulate fluid balance, supports muscle contractions, and plays a key role in maintaining healthy blood pressure. Most Americans consume far less than the recommended amount — not because potassium is hard to find, but because it is concentrated in whole fruits, vegetables, and legumes that tend to be underrepresented in typical diets.

Bananas are the most famous source, but white potatoes, sweet potatoes, avocado, lentils, and kidney beans are all excellent options and often more affordable. Reducing sodium intake alongside increasing potassium has been linked in research to better cardiovascular outcomes — though individual needs vary, and any concerns should be discussed with a doctor, particularly for those with kidney conditions.