What Are Nutrients and How Do You Get Them From Food?

Nutrients are the substances your body uses for energy, growth, repair, and regulation. You get them by eating a varied diet and, if you want to know whether you're actually meeting your needs, by tracking what you eat against nutrient targets. The practical split is macronutrients (protein, carbohydrates, fat) versus micronutrients (vitamins and minerals). This explainer covers both, the main food sources, and how to compare foods by nutrient density instead of calories alone.

Macronutrients vs. micronutrients

Category	What it includes	What it does	Typical sources
Macronutrients	Protein, carbohydrates, fat	Provide energy and raw material for tissue	Meat, fish, beans, grains, oils, dairy
Micronutrients	Vitamins and minerals	Enable reactions, support immunity, bones, blood, nerves	Fruits, vegetables, whole grains, animal products

Macronutrients are needed in large amounts and are measured in grams. Micronutrients are needed in small amounts and are measured in milligrams or micrograms. Most nutrition trackers stop at macros; the deeper value is in the micronutrient side, which is where gaps usually hide.

Key vitamins, roles, and food sources

Vitamin A — vision, skin, immune function. Liver, carrots, sweet potato, spinach.
Vitamin C — collagen, antioxidant, iron absorption. Citrus, bell peppers, broccoli, strawberries.
Vitamin D — calcium absorption, bone and muscle. Fatty fish, egg yolks, fortified milk; sunlight also matters.
Vitamin E — antioxidant. Nuts, seeds, vegetable oils, spinach.
Vitamin K — blood clotting, bone. Kale, spinach, broccoli, Brussels sprouts.
B vitamins (B1, B2, B3, B6, B12, folate) — energy metabolism, red blood cells, nerves. Whole grains, legumes, eggs, meat, leafy greens. B12 is mainly in animal products.
Calcium — bones, teeth, muscle and nerve function. Dairy, fortified plant milks, tofu, leafy greens.
Iron — oxygen transport in blood. Red meat, lentils, beans, spinach; pair with vitamin C for better absorption.
Zinc — immunity, wound healing. Meat, shellfish, legumes, seeds.
Magnesium — muscle and nerve function, blood sugar. Nuts, seeds, whole grains, leafy greens.
Potassium — fluid balance, blood pressure. Bananas, potatoes, beans, yogurt.

How to read a nutrition label or food data

Check the serving size first. All numbers below it refer to that amount, not the whole package.
Scan the macros. Protein, total carbohydrate (with fiber and sugars broken out), and fat.
Look at the micronutrient rows. Vitamins and minerals are listed as a percentage of a daily value (%DV). 5% or less is low; 20% or more is high.
Note what's missing. Labels only list a subset of nutrients. A food database that tracks 30+ nutrients will show more than the package does.
Compare like with like. Two foods only compare fairly at the same serving size.

Comparing foods by nutrient density, not just calories

Calories tell you energy; nutrient density tells you what you get for those calories. A simple method:

Pick a fixed amount, such as 100 grams or one cup.
List the nutrients each food provides at that amount.
Favor the food that delivers more vitamins, minerals, fiber, and protein for a similar calorie count.

Example: 100 g of white rice and 100 g of cooked lentils are in a similar calorie range, but lentils add substantially more fiber, iron, and folate. That's a nutrient-density win, not a calorie win.

Common nutrient gaps and simple foods that fill them

Fiber — most people fall short. Fill it with beans, lentils, oats, whole grains, berries, and vegetables.
Vitamin D — limited in food. Fatty fish, egg yolks, and fortified milk or plant milk help; sunlight is the other source.
Iron — especially relevant for menstruating people and vegetarians. Lentils, beans, spinach, and fortified cereals; combine with vitamin C.
Calcium — dairy, fortified plant milks, tofu, and leafy greens.
Potassium — bananas, potatoes, beans, and yogurt.

Tracking it in practice

If you want to see your own intake rather than estimate it, a tracker that logs meals and compares them against targets makes the gaps visible. MyFoodData, for example, states that it tracks 30+ nutrients and offers free barcode scanning, recipe and day-plan entry, and verified food badges, with a free account and no credit card required. Premium removes ads and adds features such as unlimited photo scanning, voice entry, and profile sharing. Use whatever tool fits, but the underlying method is the same: log what you eat, compare against targets, and adjust the foods that fall short.