Alma

Essential Vitamins and Minerals: What They Do and Where to Get Them

A complete guide to the vitamins and minerals your body depends on — with the best food sources, daily requirements, and signs you might be low.

Summary

The most commonly deficient vitamins and minerals in the US are vitamin D (42% of adults are low), vitamin B12 (especially in vegans/vegetarians and people over 50), iron (particularly in women under 50), magnesium (nearly 50% fall short), and potassium. Most deficiencies are fixable through diet — the right foods can cover almost every vitamin and mineral your body needs.

What are the most important vitamins and minerals?

There are 13 essential vitamins and about 16 essential minerals. Rather than listing all of them, here are the ones that matter most — because they're either hardest to get from food or most commonly deficient:

Most important vitamins

  • Vitamin D: Bone health, immune function, mood regulation. Most people don't get nearly enough from food — sunlight exposure and/or supplements fill the gap. Best food sources: fatty fish (salmon, sardines), egg yolks, fortified milk and orange juice.
  • Vitamin B12: Nerve function, red blood cell formation, energy. Found almost exclusively in animal products. Vegans need to supplement. Best food sources: beef, clams, fortified plant milks, nutritional yeast.
  • Vitamin C: Collagen synthesis, immune support, iron absorption. Easy to get from food but depleted by smoking and stress. Best food sources: bell peppers (red has 3x more than oranges), kiwi, broccoli, citrus.
  • Folate / Folic Acid (B9): DNA synthesis, essential in pregnancy. Best food sources: dark leafy greens (spinach, romaine), lentils, asparagus, fortified grains.
  • Vitamin K: Blood clotting and bone mineralization. K1 from plants, K2 from fermented foods and some animal products. Best sources: kale, spinach, broccoli, natto (fermented soy).

Most important minerals

  • Iron: Oxygen transport in blood. Deficiency is the most common nutritional deficiency worldwide. Heme iron from meat absorbs far better than non-heme iron from plants. Best sources: beef, chicken liver, oysters, lentils (with vitamin C to improve absorption).
  • Magnesium: Involved in 300+ enzymatic reactions — muscle function, sleep, blood sugar regulation. Best sources: pumpkin seeds (37% DV per oz), dark chocolate, almonds, spinach, black beans.
  • Potassium: Blood pressure, muscle contraction, nerve signals. Most Americans get far below the 4,700mg target. Best sources: potatoes, sweet potatoes, avocado, salmon, bananas.
  • Calcium: Bones, muscle contraction, nerve transmission. Best sources: dairy, fortified plant milks, canned sardines with bones, kale, tofu made with calcium sulfate.
  • Zinc: Immune function, wound healing, taste and smell. Best sources: oysters (the richest source), beef, pumpkin seeds, hemp seeds.

If you eat a varied whole-food diet with plenty of vegetables, legumes, and some animal products, you'll cover most of these without tracking. The exceptions: vitamin D (almost impossible from food alone) and vitamin B12 (if you don't eat animal products).

What foods are highest in iron?

Iron deficiency is the most common micronutrient deficiency in the world, and it hits women particularly hard due to menstruation. Here's how to get enough:

Heme iron (animal sources — highest absorption rate at 15–35%)

  • Chicken liver (3 oz): 11mg — 61% DV. One of the most nutrient-dense foods period.
  • Oysters (3 oz): 8mg — 44% DV
  • Beef (3 oz, ground): 2.2mg — 12% DV
  • Canned sardines (3 oz): 2.5mg

Non-heme iron (plant sources — 2–20% absorption rate)

  • Lentils (1 cup, cooked): 6.6mg — 37% DV
  • Tofu (3.5 oz): 3.6mg — 20% DV
  • Spinach (1 cup, cooked): 6.4mg — 36% DV (but low absorption due to oxalates)
  • White beans (1 cup): 8mg — 44% DV
  • Pumpkin seeds (1 oz): 2.5mg

Key trick: Eating vitamin C alongside plant-based iron foods increases absorption by 2–4x. Squeeze lemon on lentils, add bell pepper to beans, pair spinach with tomatoes. Conversely, coffee and tea consumed within an hour of a meal can inhibit iron absorption by 50–90%.

What are the best food sources of vitamin D?

Vitamin D is the hardest vitamin to get from food alone. Sunlight exposure triggers production in your skin, but if you live above 37° latitude (roughly the level of San Francisco or Washington DC), your skin makes very little vitamin D from October through March.

Best food sources of vitamin D:

  • Swordfish (3 oz): 566 IU — 71% DV
  • Salmon (3 oz, cooked): 447 IU — 56% DV. Wild-caught has significantly more than farmed.
  • Canned tuna (3 oz): 154 IU — 19% DV
  • Fortified cow's milk (1 cup): 115–130 IU — 15–17% DV
  • Fortified orange juice (1 cup): 100 IU
  • Egg yolks (1 large): 44 IU — 6% DV. Pasture-raised hens produce yolks with 3–4x more vitamin D.
  • UV-treated mushrooms: The only significant plant source. "Maitake mushrooms exposed to UV light" can provide up to 943 IU per 3 oz serving. Check the label — not all mushrooms are UV-treated.

The daily recommended vitamin D intake is 600 IU for adults, but many experts (and the Endocrine Society) recommend 1,500–2,000 IU for optimal blood levels. A standard supplement (1,000–2,000 IU vitamin D3) is a reasonable insurance policy for most people.

Which vitamins and minerals are most people actually deficient in?

Based on NHANES data (the largest ongoing nutrition survey of Americans):

  • Vitamin D: 42% of US adults are deficient (below 20 ng/mL). Rates are higher in people with darker skin, those who live in northern climates, and people who spend little time outdoors.
  • Potassium: Only 3% of Americans meet the adequate intake of 4,700mg/day. Processed food diets are low in potassium; only whole foods (especially fruits and vegetables) provide adequate amounts.
  • Magnesium: Nearly 48% of Americans fall short of the RDA. Magnesium is found in whole grains, legumes, nuts, and seeds — all foods that are underrepresented in typical Western diets.
  • Vitamin E: 90% of Americans don't meet the RDA. Best sources are nuts, seeds, and plant oils — not foods most people prioritize.
  • Calcium: About 38% of adults don't meet calcium recommendations, particularly women over 50 and those who avoid dairy.
  • Iron: 10% of women of childbearing age are iron deficient. Almost never a problem in men eating varied diets.
  • Vitamin B12: More common in vegetarians, vegans, and adults over 50 (stomach acid declines with age, reducing B12 absorption).

The pattern is consistent: processed food diets fail on micronutrients because the manufacturing process strips most vitamins and minerals out, and enrichment only adds back a handful.

How Alma Helps

Alma tracks 25 vitamins and minerals in your meals every day — including all the commonly deficient ones. Your weekly Alma Score reflects not just calories and macros but how well you're covering your micronutrient needs across the board.