Food · lesson 3 of 12
The nutrients people actually run low on
The genuine, common shortfalls — and what deficiency really does.
7 min read · reviewed October 2026
Most people in wealthy countries get plenty of calories — and still under-consume a short, predictable list of micronutrients. These aren't exotic; they're the everyday gaps that show up again and again in dietary surveys.
Roughly what fraction of adults in the US/Europe have vitamin D levels below the commonly recommended sufficiency threshold? (slider = percent)
Somewhere between 5 and 90 %.
Reveal the answer →
~40% (estimates vary widely)
Estimates depend heavily on the cutoff used, the season, latitude, and skin tone — published figures range from roughly a quarter to well over half of adults below sufficiency, with ~40% a defensible middle estimate for many populations. The point isn't the exact number: vitamin D shortfall is genuinely common, driven by indoor life, sunscreen, higher latitudes, and the fact that very few foods contain meaningful amounts.
The common shortfalls — and what deficiency does
Skin makes it from sunlight, but modern indoor life and northern latitudes leave many short. Low D impairs calcium absorption and bone health, and is linked to weaker immune function and low mood. Few foods supply much — fatty fish, egg yolk, fortified dairy.
A large share of adults fall below the requirement. Refining strips it from grains, and modern diets lean processed. Shortfall shows as muscle cramps, poor sleep, fatigue, and worse stress tolerance. Sources: leafy greens, nuts, seeds, legumes, whole grains, dark chocolate.
The marine omega-3s most people barely eat unless they have oily fish regularly. They're structural fats for brain and eye, and anti-inflammatory. Plant ALA (flax, walnuts) converts to EPA/DHA only poorly. Sources: salmon, sardines, mackerel; algae oil for vegans.
Most people get far less than the target — the flip side of eating too few fruits and vegetables (and too much sodium). Adequate potassium supports healthy blood pressure. Sources: potatoes, beans, leafy greens, bananas, yogurt, tomato.
Technically not a micronutrient, but the single most under-eaten thing on the plate — most adults get about half the target. It feeds gut bacteria, steadies blood sugar, and supports heart health. Sources: legumes, whole grains, vegetables, fruit, nuts.
Found almost only in animal foods, so vegans and vegetarians are at real risk — and absorption drops with age, making older adults vulnerable even on a mixed diet. Deficiency causes fatigue, nerve problems, and a specific anemia. Sources: meat, fish, eggs, dairy; fortified foods or a supplement for plant-based eaters.
The most common deficiency worldwide. Menstruating women are especially at risk from monthly losses. Low iron causes fatigue, breathlessness, and poor concentration before it becomes anemia. Sources: red meat, shellfish (heme); beans, lentils, fortified grains, spinach (non-heme).
Calcium — many fall short, risking weaker bones long-term (dairy, fortified plant milks, leafy greens, tofu). Choline — newly recognized as widely under-consumed; vital for brain and liver (eggs, liver, soy). Iodine — needed for thyroid hormones; intake has slipped as people use less iodized salt and more sea/specialty salts (iodized salt, seafood, dairy).
Of US adults fall short of the magnesium requirement from food alone — one of the most consistently under-consumed minerals.
Source: US dietary intake surveys (NHANES-based estimates)
Formulate rolls up your logged foods and supplements into a coverage view, so you can spot your own gaps instead of guessing from a generic list.