Every nutrient, and exactly how much you need

Carbohydrates are the body's primary and preferred energy source, and the only fuel the brain and red blood cells use efficiently. The RDA is 130 g/day for adults and children, set to cover the brain's glucose needs, while the acceptable range is 45 to 65 percent of daily calories. Quality matters: whole grains, fruits, vegetables, and legumes are preferred over refined starches and added sugars.

Dietary fiber is the part of plant foods the body cannot digest. It supports regular bowel movements, feeds beneficial gut bacteria, helps lower cholesterol and blood sugar, and promotes fullness. Values are set as Adequate Intakes based on 14 g of fiber per 1000 calories, which works out to about 38 g/day for adult men and 25 g/day for adult women, dropping after age 50.

Protein supplies the amino acids the body uses to build and repair muscle, skin, and organs, and to make enzymes, hormones, and antibodies. The RDA is 0.8 g per kg of body weight for adults, and the acceptable range is 10 to 35 percent of daily calories. Active people, older adults, and those recovering from illness often need more.

Fat is a concentrated energy source that carries the fat-soluble vitamins A, D, E, and K, supplies essential fatty acids, and helps make cell membranes and hormones. There is no RDA for total fat in adults, only an acceptable range of 20 to 35 percent of daily calories; the emphasis is on replacing saturated fat with unsaturated fats. Infants have an Adequate Intake because fat is critical for early growth.

Water makes up about 60 percent of body weight and is essential for temperature regulation, nutrient transport, joint lubrication, and waste removal. The Adequate Intake for total water is about 3.7 liters/day for men and 2.7 liters/day for women, counting water from all beverages and foods. Roughly 80 percent of intake comes from drinks and 20 percent from food.

Biotin, also known as vitamin B7, is a water-soluble vitamin that acts as a coenzyme for carboxylase enzymes, which are essential for metabolizing fats, carbohydrates, and proteins. It also plays a role in gene regulation. Biotin is found in a wide range of foods and is made by gut bacteria, so deficiency is uncommon.

Choline is an essential, water-soluble nutrient often grouped with the B vitamins. The body makes some on its own, but not enough, so it must also come from the diet. It is needed to build cell membranes, to make the neurotransmitter acetylcholine, and for methylation and fat transport in the liver. Adequate choline is especially important during pregnancy for fetal brain development.

Folate is a water-soluble B vitamin (vitamin B9) needed to make DNA and to divide cells. Natural folate is found in foods, while folic acid is the synthetic form in supplements and fortified foods. Because folic acid is absorbed more efficiently, intakes are measured in micrograms of dietary folate equivalents (mcg DFE). Adequate folate before and during early pregnancy sharply lowers the risk of neural tube defects.

Niacin is a water-soluble B vitamin essential for turning food into energy. Requirements are expressed in milligrams of niacin equivalents (mg NE) because the body can also make niacin from the amino acid tryptophan.

Pantothenic acid, or vitamin B5, is a water-soluble vitamin found in nearly all plant and animal foods. It is a building block of coenzyme A and acyl carrier protein, essential for making and breaking down fats and for releasing energy from carbohydrates, fats, and proteins. Because it is so widespread, deficiency is very rare.

Riboflavin is a water-soluble B vitamin at the center of energy production from food. It also helps the body use other B vitamins and acts in antioxidant defense.

Thiamin is a water-soluble B vitamin that helps convert the food you eat into energy. It is essential for normal nerve, muscle, and heart function.

Vitamin A is a fat-soluble vitamin that comes as preformed retinol from animal foods and as provitamin A carotenoids like beta-carotene from plants. It is essential for normal vision, immune defense, and healthy growth.

Vitamin B12, also called cobalamin, is a water-soluble vitamin required for red blood cell formation, DNA synthesis, and normal nerve function. It occurs naturally only in animal foods and in fortified products. Absorption depends on stomach acid and intrinsic factor, so many older adults and people with certain conditions absorb it poorly even when intake is adequate.

Vitamin B6 is a water-soluble vitamin whose most active form is pyridoxal 5'-phosphate (PLP). It serves as a coenzyme for more than 100 enzyme reactions, most of them in protein and amino acid metabolism, and it supports hemoglobin, neurotransmitters, and immune function. Because it is water-soluble, the body stores little, so a regular dietary supply is needed.

Vitamin C is a water-soluble vitamin and antioxidant that the body cannot make or store, so it must come from the diet. It is needed to build collagen and to support immune defenses.

Vitamin D is a fat-soluble vitamin that the body can also make in skin exposed to sunlight. It is essential for calcium absorption and for building and maintaining strong bones.

Vitamin E is a fat-soluble antioxidant that protects cell membranes from damage by free radicals. Alpha-tocopherol is the only form the human body maintains and uses to meet requirements.

Vitamin K is a fat-soluble vitamin best known for its essential role in blood clotting. It also helps build and maintain healthy bones by activating proteins that bind calcium.

Calcium is the most abundant mineral in the body, with about 99 percent stored in bones and teeth, where it provides structure and hardness. The remaining 1 percent is essential for muscle function, nerve transmission, blood clotting, and hormone secretion. Because the body cannot make calcium, needs must be met through diet, and requirements rise in adolescence and again in later life to protect bone.

Chloride is the major negatively charged ion in the fluid outside cells, where it works with sodium to maintain fluid balance and normal cell function. It is also needed to make stomach acid for digestion and helps maintain acid-base balance. Because most dietary chloride comes together with sodium as salt, intake tracks closely with sodium, and its needs are set as Adequate Intakes.

Chromium, in its trivalent (chromium III) form, is a trace mineral that appears to enhance the action of insulin and thereby influence carbohydrate, fat, and protein metabolism. Because evidence was insufficient to set an RDA, intake targets are given as Adequate Intake (AI) values. Notably, chromium requirements decline after age 50, and no upper limit has been established. Hexavalent chromium, an industrial pollutant, is toxic and unrelated to the dietary form.

Copper is an essential trace mineral that acts as a cofactor for enzymes involved in energy production, iron metabolism, connective tissue formation, and the nervous system. It works closely with iron and is needed to move iron into red blood cells. Because copper and zinc compete for absorption, very high zinc intakes can trigger copper deficiency. Requirements are small and measured in micrograms.

Iodine is an essential trace mineral that the thyroid gland uses to make thyroid hormones, which regulate metabolism and are critical for brain and skeletal development, especially during pregnancy and infancy. Iodine deficiency remains a leading preventable cause of intellectual disability worldwide. Iodized salt and dairy are major dietary sources. Requirements are set as an RDA in micrograms and rise sharply during pregnancy.

Iron is an essential trace mineral central to hemoglobin, the protein in red blood cells that carries oxygen from the lungs to the tissues. It also supports myoglobin, energy metabolism, and many enzymes. The body tightly regulates iron because it has no active way to excrete excess. Needs differ sharply by sex and life stage: menstruating women lose iron monthly and require far more than men, while pregnancy raises demand higher still.

Magnesium is a cofactor for more than 300 enzyme systems that regulate protein synthesis, muscle and nerve function, blood glucose control, and blood pressure. It is needed to produce energy and to build DNA and bone. About half of the body's magnesium is stored in bone, and many people fall short of the recommended intake through diet alone.

Manganese is an essential trace mineral that serves as a cofactor for enzymes involved in metabolism, bone formation, and antioxidant defense. It is needed for the processing of carbohydrates, amino acids, and cholesterol. Because the evidence was insufficient to set an RDA, intake targets are given as Adequate Intake (AI) values. Deficiency is very rare because manganese is widespread in plant foods.

Molybdenum is an essential trace mineral that serves as a cofactor for four enzymes, including those that break down sulfur-containing amino acids and process toxic byproducts. Requirements are very small, set as an RDA in micrograms, and dietary deficiency is essentially unknown in healthy people because molybdenum is widely available in legumes, grains, and nuts. The same requirement applies to adult men and women.

Phosphorus is the second most abundant mineral in the body after calcium, with about 85 percent found in bones and teeth as calcium phosphate. It is a core component of DNA, RNA, cell membranes, and the energy molecule ATP, and it helps regulate acid-base balance. Phosphorus is widespread in the food supply, so dietary deficiency is rare in healthy people.

Potassium is the main positively charged ion inside cells and is essential for normal fluid balance, nerve transmission, and muscle contraction, including the heartbeat. Adequate potassium helps blunt the blood-pressure-raising effect of sodium and is associated with reduced risk of stroke and kidney stones. Its intake levels are set as Adequate Intakes because the data are not sufficient to set an RDA.

Selenium is an essential trace mineral that is a structural component of selenoproteins, which function in antioxidant defense, thyroid hormone metabolism, DNA synthesis, and reproduction. The selenium content of food depends heavily on the selenium level of the soil where crops are grown or animals are raised. Requirements are set as an RDA in micrograms, with the same value for adult men and women.

Sodium is an essential electrolyte that maintains fluid volume outside cells and supports nerve and muscle function. Only a small amount is required, and true deficiency is rare, while the far more common problem is excess: most people consume well above what they need, which raises blood pressure and cardiovascular risk. Intake levels are set as Adequate Intakes, paired with a Chronic Disease Risk Reduction level.

Zinc is an essential trace mineral required for the activity of hundreds of enzymes and for protein and DNA synthesis. It is critical for immune function, wound healing, growth, and the senses of taste and smell. The body has no specialized zinc storage system, so a regular dietary supply is needed. Because plant compounds like phytate bind zinc, vegetarians and vegans may absorb less of it.

Added sugars are sugars and syrups added to foods and drinks during processing or preparation, unlike the natural sugars in fruit and milk. They add calories with little nutrition and are linked to weight gain, tooth decay, and heart disease. The Dietary Guidelines advise keeping added sugars to less than 10 percent of daily calories, and the American Heart Association suggests tighter limits of about 25 g/day for women and 36 g/day for men.

Caffeine is a natural stimulant found in coffee, tea, cacao, and many soft and energy drinks. It boosts alertness and can improve exercise performance, but too much causes jitters, insomnia, and a racing heart. The FDA cites up to 400 mg/day as generally safe for healthy adults, and health authorities advise pregnant people to limit intake to about 200 mg/day.

Dietary cholesterol is a waxy substance found only in animal foods. The body also makes its own cholesterol, so none is required from food. The 2020-2025 Dietary Guidelines set no strict numerical limit but advise keeping intake as low as possible within a healthy eating pattern. The older guideline of 300 mg/day is still a useful reference point.

Saturated fat is a type of fat found mainly in animal products and some tropical oils that is solid at room temperature. High intake raises LDL (bad) cholesterol and heart disease risk. The Dietary Guidelines advise keeping saturated fat to less than 10 percent of daily calories and replacing it with unsaturated fats.

Alanine is a non-essential amino acid the body makes easily. It plays a central role in moving energy around the body, especially by helping the liver make glucose during exercise and fasting.

Arginine is a conditionally essential amino acid, meaning the body usually makes enough but may need extra from food during illness, injury, or rapid growth. It is the direct precursor to nitric oxide, which relaxes blood vessels.

Aspartic acid, or aspartate, is a non-essential amino acid the body makes readily. It helps produce energy, clears ammonia through the urea cycle, and acts as a neurotransmitter.

Cysteine is a conditionally essential, sulfur-containing amino acid the body makes from methionine. It is the key ingredient in glutathione, the body's master antioxidant, and its sulfur bonds give shape to proteins like keratin in hair and nails.

Cystine is simply two cysteine molecules joined by a sulfur bond, the stable form cysteine takes in many proteins. It gives strength to keratin in hair, skin, and nails and helps maintain the shape of many proteins.

Glutamic acid, or glutamate, is a non-essential amino acid the body makes readily. It is one of the most abundant amino acids in food and the brain's main excitatory neurotransmitter, and it gives foods their savory umami taste.

Glycine is the smallest amino acid and conditionally essential, meaning the body makes it but may not make enough during growth or high demand. It makes up about a third of collagen and helps build creatine and the antioxidant glutathione.

Histidine is an essential amino acid, meaning the body cannot make enough of it and it must come from food. It is a building block of protein and a precursor to histamine, and it helps form hemoglobin and buffer the blood.

Isoleucine is an essential amino acid and one of the three branched-chain amino acids (BCAAs). The body cannot make it, so it must come from food, where it supports muscle repair and energy use during exercise.

Leucine is an essential amino acid and the most anabolic of the three branched-chain amino acids. The body cannot make it, so it must come from food, and it is the key signal that switches on muscle protein synthesis.

Lysine is an essential amino acid that the body cannot make, so it must come from food. It is needed to build proteins, form collagen, and absorb calcium, and it is the amino acid most often limiting in grain-based diets.

Methionine is an essential amino acid that the body cannot make, so it must come from food. It starts nearly every protein chain, donates methyl groups for many reactions, and can be used to make cysteine, so the two are measured together as the sulfur amino acids.

Phenylalanine is an essential amino acid that the body cannot make, so it must come from food. It builds proteins and is the precursor to tyrosine, which in turn makes dopamine, norepinephrine, and adrenaline, so the two are measured together as the aromatic amino acids.

Proline is a conditionally essential amino acid the body normally makes on its own. It is a major building block of collagen and gives that protein its structural strength, so it is important for skin, joints, and wound healing.

Serine is a non-essential amino acid the body makes from other compounds. It is important for building proteins, cell membranes, and DNA, and it supports the nervous system.

Threonine is an essential amino acid that the body cannot make, so it must come from food. It helps build proteins and is especially concentrated in collagen, elastin, and the mucus that protects the gut lining.

Tryptophan is an essential amino acid that the body cannot make, so it must come from food. It builds proteins and is the precursor to serotonin and melatonin, the messengers that regulate mood and sleep, and it also helps make niacin (vitamin B3).

Tyrosine is a conditionally essential amino acid the body makes from phenylalanine. It is the raw material for dopamine, norepinephrine, and adrenaline, as well as thyroid hormones and the pigment melanin.

Valine is an essential amino acid and one of the three branched-chain amino acids (BCAAs). The body cannot make it, so it must come from food, where it supports muscle repair, energy during exercise, and nervous system function.

Alpha-linolenic acid (ALA) is the essential plant omega-3 fat, meaning the body cannot make it and must get it from food. It is found in flaxseed, chia, walnuts, and canola oil, and the body can partly convert it into the longer-chain omega-3s EPA and DHA.

Arachidonic acid is a long-chain omega-6 fat the body makes from linoleic acid and also gets from meat, eggs, and fish. It is a major building block of cell membranes and the source of signaling molecules involved in inflammation, immunity, and muscle repair.

Capric acid is a medium-chain saturated fatty acid, one of the fats in MCT oil. It is found in coconut oil, palm kernel oil, and dairy fat.

Caprylic acid is a medium-chain saturated fatty acid and the shortest of the common MCTs used in MCT oil. It is found in coconut oil, palm kernel oil, and dairy fat.

Dihomo-gamma-linolenic acid (DGLA) is a long-chain omega-6 fat the body makes from GLA. It is notable because it produces anti-inflammatory signaling molecules, in contrast to the pro-inflammatory products of its relative arachidonic acid.

DHA (docosahexaenoic acid) is a long-chain omega-3 fat and a major structural building block of the brain, nervous system, and the retina of the eye. It is found in oily fish and algae, and it is especially important during pregnancy and infancy.

DPA (docosapentaenoic acid) is a long-chain omega-3 fat that sits between EPA and DHA in the body's omega-3 pathway. It is found in fish and some meats and appears to share the heart and anti-inflammatory benefits of the better-known omega-3s.

Eicosenoic acid is a long-chain monounsaturated omega-9 fatty acid with a 20-carbon backbone. It appears in small amounts in many plant oils, nuts, and some fish.

EPA (eicosapentaenoic acid) is a long-chain omega-3 fat found mainly in oily fish and algae. It is best known for helping calm inflammation and supporting heart health, and it works closely with DHA.

Erucic acid is a long-chain monounsaturated omega-9 fatty acid found naturally in rapeseed, mustard, and other Brassica plants. Because of historical safety concerns, food-use rapeseed (canola) has been bred to contain very little of it.

Gamma-linolenic acid (GLA) is an omega-6 fat the body normally makes from linoleic acid. Unlike most omega-6 fats, it can have anti-inflammatory effects, and it is found in evening primrose, borage, and blackcurrant seed oils.

Lauric acid is a saturated fatty acid and the main fat in coconut oil and palm kernel oil. It is often grouped near the medium-chain fats but behaves in some ways like a longer-chain saturated fat.

Linoleic acid (LA) is the essential omega-6 fat, meaning the body cannot make it and must get it from food. It is the most common polyunsaturated fat in the diet, abundant in vegetable oils, nuts, and seeds, and it is vital for skin and cell membranes.

Monounsaturated fats are dietary fats whose fatty acids have a single double bond in their carbon chain. They are liquid at room temperature and are considered one of the heart-healthier types of fat.

Myristic acid is a saturated fatty acid found mainly in dairy fat, coconut oil, and palm kernel oil. Gram for gram, it is one of the strongest saturated fats at raising LDL cholesterol.

Oleic acid is the most common monounsaturated fatty acid in the diet and an omega-9 fat. It is the main fatty acid in olive oil and is found in many nuts and seeds.

Omega-3 is a family of polyunsaturated fats that are important for the heart, brain, and eyes and help calm inflammation. The main dietary members are ALA from plants and EPA and DHA from fish and algae.

Omega-6 is a family of polyunsaturated fats found mainly in vegetable oils, nuts, and seeds. The main member, linoleic acid, is essential, and omega-6 fats are important for skin, cell membranes, and cell signaling.

Palmitic acid is the most common saturated fatty acid in the diet and in the human body. It is abundant in meat, dairy, and palm oil, and it tends to raise LDL cholesterol.

Polyunsaturated fats are dietary fats with two or more double bonds in their carbon chain. They include the two essential fat families, omega-3 and omega-6, and are liquid at room temperature and considered heart-healthy.

Stearic acid is a long-chain saturated fatty acid found in meat, cocoa butter, and some vegetable fats. Unlike most saturated fats, it appears to have a relatively neutral effect on LDL cholesterol.