Identify vitamin and mineral deficiencies by comparing your daily intake to RDA targets. Find gaps and get food source recommendations.
Micronutrient gaps are more common than they first appear, especially when food variety is limited or calories are restricted. This calculator compares your estimated intake against the Recommended Dietary Allowance (RDA) or Adequate Intake (AI) for your age and sex, then flags nutrients that fall meaningfully below target.
The goal is not to diagnose deficiency from a single worksheet. It is to help you spot likely shortfalls, compare them with common upper-limit cautions, and decide whether food changes or a targeted supplement conversation is worth considering.
Blind supplementation can waste money and, for some nutrients, push intake above safe upper limits. This tool identifies the gaps first so you can decide whether food changes or focused supplementation makes the most sense.
Gap = RDA Target – Daily Intake Gap Percentage = (Gap ÷ RDA Target) × 100 Status Classification: • Critically Low: <50% of RDA • Below Target: 50–99% of RDA • Adequate: 100–200% of RDA • High: >200% of RDA (check upper limits)
Result: 5 gaps found: Vitamin D (40%), Calcium (46%), Potassium (43%), Iron (67%), Vitamin C (93%)
For a 31–50 year old female: Vitamin D intake of 8 mcg vs RDA of 15 mcg = 53% (Below Target). Calcium 600 mg vs RDA 1,000 mg = 60% (Below Target). Potassium 2,000 mg vs AI 2,600 mg = 77% (Below Target). Iron 12 mg vs RDA 18 mg = 67% (Below Target). Vitamin C 70 mg vs RDA 75 mg = 93% (Below Target, but close). These are the five shortfalls highlighted by the worksheet.
Women of reproductive age: iron (due to menstruation), folate (critical before pregnancy), calcium (lower dairy intake). Older adults: vitamin D (reduced skin synthesis), B12 (reduced stomach acid absorption), calcium. Vegetarians/vegans: B12 (no plant sources), iron (lower bioavailability), zinc, omega-3. Athletes: iron (increased losses), magnesium (sweat losses), vitamin D (if indoor training). Dieters: nearly all micronutrients due to reduced food intake.
Fatigue can indicate iron, B12, vitamin D, or magnesium deficiency. Muscle cramps suggest magnesium or potassium. Frequent illness may indicate vitamin C, D, or zinc deficiency. Hair loss can be linked to iron, zinc, or biotin deficiency. Bone pain suggests vitamin D deficiency. Mouth sores can indicate B vitamins. These symptoms overlap with many conditions, so blood testing is needed for diagnosis.
Not all nutrients are equally absorbed. Heme iron (from meat) is absorbed at 15–35%, while non-heme iron (plants) is absorbed at 2–20%. Calcium from dairy is absorbed at ~30%, from spinach only ~5% (due to oxalates). Vitamin C enhances iron absorption, while coffee/tea inhibit it. Vitamin D aids calcium absorption. These interactions matter when planning how to close nutrient gaps.
Last updated:
This worksheet compares estimated daily intake against age- and sex-specific DRI targets (RDA or AI) and classifies each nutrient by percent of target. The gap bands are a planning aid, not a diagnosis. Food suggestions are intentionally general and are meant to help close common shortfalls with diet first, then targeted supplements if needed.
RDA (Recommended Dietary Allowance) is the amount sufficient to meet the needs of 97–98% of healthy individuals, based on strong scientific evidence. AI (Adequate Intake) is used when insufficient evidence exists for an RDA — it's an estimated adequate amount based on observed intakes. Both are valid targets, but AI has more uncertainty. Potassium, for example, uses AI rather than RDA.
Shortfalls are common, but they vary by nutrient and by diet pattern. Vitamin D, potassium, magnesium, calcium, and iron are frequent areas to check, especially when calories are restricted or food variety is low.
Yes. Fat-soluble vitamins (A, D, E, K) accumulate in body fat and can reach toxic levels. Excess vitamin A causes liver damage; excess iron can cause organ damage. The Tolerable Upper Intake Level (UL) is the maximum daily amount unlikely to cause harm. Most people won't exceed ULs from food alone, but supplements can push you over.
A multivitamin can serve as "insurance" for common gaps, but it's not a replacement for a balanced diet. Many multivitamins contain inadequate amounts of the most-needed nutrients (vitamin D, magnesium, potassium) while providing excess of others. Targeted supplementation based on identified gaps is more effective and cost-efficient.
Vitamin D (very few food sources; mostly from sun exposure), potassium (requires very high vegetable/fruit intake), magnesium (soil depletion has reduced content in foods), and omega-3 fatty acids (requires regular fatty fish consumption). Vitamin B12 is impossible to get on a strict vegan diet without supplementation.
Significantly. Below 1,500 kcal/day, it becomes very difficult to meet all micronutrient needs from food alone. Below 1,200 kcal, deficiencies are nearly guaranteed without supplementation. This is why crash diets and very low-calorie diets often cause fatigue, hair loss, and weakened immunity — common signs of micronutrient deficiencies.