Micronutrients: Vitamins, Minerals, and Electrolytes
Linas JuozėnasShare
Micronutrients
Understand the vitamins and minerals that help your body use food, maintain tissues and keep moving.
A meal provides much more than fuel. It supplies substances that help cells carry out chemical reactions, blood transport oxygen, bones renew themselves and nerves communicate with muscles. Vitamins and minerals participate in this work throughout life.
Understanding them makes ordinary decisions easier: choosing useful food combinations, checking a fortified drink, planning a restricted diet or deciding whether a supplement has a clear purpose.
This guide brings those decisions together. It explains the main nutrients, the overlap between minerals and electrolytes, and the difference between meeting a need and simply taking more.
Requirements may be measured in milligrams or micrograms, but adequate provision matters.
Food variety, enough total food, absorption and any fortified products shape intake.
Prevention or treatment of a shortfall is different from assuming a larger dose improves performance.
What micronutrients are—and how they work
Micronutrients are vitamins and minerals required in relatively small quantities. Their functions include supporting normal growth, metabolism and health.[1] They do not supply calories, although several help the body release and use energy from carbohydrate, fat and protein.
Vitamins are organic compounds with specific biological functions. Minerals are elements, such as calcium, iron and zinc, that the body uses in structures and physiological processes. Neither category is interchangeable with the other.
Electrolytes overlap with minerals
An electrolyte forms electrically charged particles, or ions, in a solution. In body fluids, sodium, potassium, calcium and magnesium ions are important examples. Chloride, phosphate and bicarbonate also contribute to fluid chemistry and physiological regulation.
“Electrolyte” therefore describes a chemical role. It is not a separate collection of nutrients that must always come from a sports drink. Several minerals discussed in this article are also electrolytes.
Essential does not mean unlimited
A nutrient can be necessary for a process without a larger intake making that process progressively better. Once needs are met, another dose may add little benefit, and some nutrients can cause harm in excess.
The practical aim is dependable adequacy: enough of each required nutrient in a pattern that also supplies energy, protein, fats and other components of food. A vitamin tablet cannot replace the food needed to sustain daily life.
Requirements, label values and upper limits answer different questions
Requirements vary with age, life stage and other circumstances. EFSA's dietary reference values help professionals assess and plan nutrition for healthy populations; they are not exact personal prescriptions.[2]
Reference intake
A population reference intake aims to cover nearly all healthy people in a defined group. An adequate intake is used when evidence does not support deriving that value.
Label percentage
On EU labels, a percentage of the nutrient reference value provides a standard comparison. It does not measure your absorption or prove that your whole diet meets your needs.[3]
Upper intake level
A tolerable upper intake level concerns sustained intake unlikely to cause harm. It is a safety boundary, not an amount to aim for. Its scope can differ between nutrients.[4]
Check the unit and the actual serving
One milligram, written mg, equals 1,000 micrograms, written µg or mcg. Confusing these units creates a thousandfold error. The figure for a capsule may also differ from the figure for the manufacturer's suggested daily serving.
Use labels to compare like with like. If a drink lists calcium per 100 mL, the amount you receive depends on how much you drink. If several products contain the same vitamin, consider their combined contribution.
Intake below a reference value on one day does not diagnose a deficiency. Conversely, a large label percentage does not prove that a product is necessary or suitable. Clinical treatment can involve different amounts and requires its own plan.
Fat-soluble vitamins have distinct functions and cautions
These vitamins are handled alongside dietary fat during absorption. Their storage and turnover differ; grouping them together does not mean that they accumulate equally or share the same toxicity risk.
Meals containing some fat can help with absorption. There is no need to turn an ordinary meal into a high-fat meal or buy a combined supplement solely because these vitamins share a category.
| Vitamin | What it supports | Useful food sources and context |
|---|---|---|
| A | Vision, immune function and normal growth. | Carrots, sweet potatoes and leafy greens supply provitamin A carotenoids. Eggs and dairy provide preformed vitamin A.[5] |
| D | Calcium absorption and bone mineralisation. | Fortified foods, egg yolks and certain UV-exposed mushrooms contribute. Skin can produce vitamin D with suitable UVB exposure, but production varies.[6] |
| E | Protection of cell membranes from oxidative damage. | Nuts, seeds and vegetable oils are useful sources. A biological antioxidant role does not establish a benefit from high-dose supplements.[7] |
| K | Activation of proteins involved in blood clotting and bone metabolism. | Leafy vegetables provide K1. Some fermented foods, particularly natto, supply K2 forms; amounts vary.[8] |
The form and amount matter
Preformed vitamin A and food carotenoids do not have identical risk profiles. Excess preformed vitamin A is especially concerning during pregnancy. High-dose beta-carotene supplements also have recognised risks in smokers and some other exposed groups; ordinary vegetables are not equivalent to those supplements.[5]
Large supplemental vitamin E intakes can increase bleeding risk. Vitamin K requires particular attention with medicines such as warfarin: consistent intake and coordinated care matter more than simply avoiding green vegetables.[7][8]
Food storage in the body is a reserve, not proof that deficiency cannot occur. Poor absorption and restricted intake can still create problems.
B vitamins support metabolism, cells and nerves
The B vitamins have related but different jobs. Several become parts of coenzymes: small molecules that help enzymes carry out reactions. Others are especially important in DNA synthesis, blood-cell formation or nerve function.
A product described as a “B complex” combines nutrients; it does not establish that you need additional amounts of all eight. Useful sources are spread across everyday foods.
| Vitamin | Examples of its work | Foods to consider |
|---|---|---|
| B1 · Thiamin | Helps reactions involved in energy metabolism and normal cellular function. | Whole grains, legumes and seeds.[9] |
| B2 · Riboflavin | Forms coenzymes involved in energy production and cellular processes. | Milk, yoghurt, eggs, almonds and suitably fortified foods.[10] |
| B3 · Niacin | Contributes to NAD and NADP, which participate in metabolic reactions. | Peanuts, other nuts, legumes and grains. The body also makes niacin from the amino acid tryptophan.[11] |
| B5 · Pantothenic acid | Helps form coenzyme A, important in processing fats and other molecules. | Widely distributed; examples include mushrooms, sunflower seeds, eggs and whole grains.[12] |
| B6 | Supports amino-acid metabolism, neurotransmitter synthesis and haemoglobin formation. | Chickpeas, potatoes, bananas and fortified products.[13] |
| B7 · Biotin | Helps enzymes process fats, glucose and amino acids. | Cooked eggs, nuts, seeds and sweet potatoes.[14] |
| B9 · Folate | Supports DNA synthesis and cell division. | Legumes, leafy vegetables and foods fortified with folic acid. Fortification varies by product and country.[15] |
| B12 | Supports nerve function, DNA synthesis and red blood cells. | Dairy, eggs and reliably fortified foods; a vegan diet needs planned B12 provision.[16] |
Water-soluble does not mean harmless at any dose
Although many excess B vitamins are excreted, this does not make every large dose safe. Sustained high B6 intake can damage peripheral nerves. EFSA's adult upper intake level is 12 mg/day from all sources, including during pregnancy and lactation; it is not a recommended target.[17]
Biotin supplements can interfere with certain laboratory tests. Tell the clinician or laboratory about products you take, including hair-and-nail formulas, so they can give appropriate preparation instructions.[14]
B12 is another reason to avoid blanket rules about storage: the body can hold reserves for years. Feeling well after a short period of low intake therefore does not establish that a diet will remain adequate.
Support connective tissues with regular food sources
Vitamin C is needed to make collagen, contributes to antioxidant protection and supports normal immune function. It also improves absorption of non-haem iron from plant foods.[18]
Peppers, citrus fruit, berries, kiwi and broccoli can contribute. Prolonged storage and cooking can reduce vitamin C; steaming or microwaving may limit some losses. Including both raw and cooked produce is a practical approach.
Severe, prolonged deficiency causes scurvy. This is different from assuming that every episode of tiredness or every cold indicates a need for a large dose. High supplemental amounts can cause diarrhoea and abdominal discomfort.
Make a useful pairing
Add peppers to a bean salad, serve fruit alongside a lentil meal, or include broccoli with tofu. These are ordinary food combinations that connect a nutrient's role with something you can prepare and enjoy.
You do not need to calculate the vitamin C content of every bite. Build repeatable opportunities to eat suitable produce, using options that fit your budget, season and preferences.
The major minerals serve much more than one purpose
“Major” refers to the amount required, not to a ranking of importance. Calcium, phosphorus, magnesium, sodium, potassium and chloride all contribute to normal function.
| Mineral | Examples of its role | Practical sources or considerations |
|---|---|---|
| Calcium | Bone and tooth structure; muscle, nerve and clotting functions. | Dairy, calcium-fortified alternatives and calcium-set tofu. Check the product and portion.[19] |
| Phosphorus | Bone mineral, cell membranes and ATP, a molecule used in cellular energy transfer. | Legumes, dairy, nuts and whole grains. It is widely available in food.[20] |
| Magnesium | Enzyme activity, energy metabolism and normal nerve and muscle function. | Legumes, whole grains, leafy vegetables, nuts and seeds.[21] |
| Potassium | Fluid balance within cells and electrical gradients used by nerves and muscles. | Potatoes, beans, vegetables, fruit and yoghurt; bananas are one option among many.[22] |
| Sodium and chloride | Fluid and electrolyte regulation. | Table salt supplies both. Prepared foods can provide substantial amounts even when little salt is added at the table.[23] |
Keep the whole person in view
Kidneys regulate the handling of several minerals. Kidney disease can change what is appropriate, especially for potassium and phosphorus. Potassium-containing salt substitutes or supplements should not be adopted automatically when kidney function or medicines affect potassium balance.[22][20]
Magnesium in supplements can cause diarrhoea, and impaired kidney function increases the risk from excessive intake. The weight of a magnesium compound is not necessarily the amount of elemental magnesium it supplies; compare the declared nutrient amount.[21]
Routine meals offer several minerals at once. A bean-and-buckwheat bowl, for example, need not be assigned to one “mineral category.” Its value comes from the combination and the rest of the diet.
Trace minerals need reliable sources and proportionate intake
The word “trace” can make these nutrients sound optional. They are required in smaller amounts, but too little or too much can still matter. Iron receives its own discussion in the next section; the examples below show other important roles.
Zinc
Zinc supports enzyme activity, wound healing, immune function and taste. Legumes, nuts and seeds contribute, although phytate in plant foods can reduce absorption. Soaking or fermentation can improve availability in some foods.[24]
Repeated high-dose zinc can reduce copper absorption. More zinc is not automatically better for immunity.
Copper
Copper-containing enzymes participate in iron metabolism, connective-tissue formation and other processes. Nuts, seeds, whole grains and cocoa are useful food sources.[25]
The interaction with zinc illustrates why adding large amounts of one mineral can create a problem elsewhere.
Iodine
Iodine is needed for thyroid hormones. Iodised salt, dairy, eggs and appropriately fortified foods can contribute, but amounts vary. Check labels rather than assuming every salt or plant drink contains iodine.[26]
Seaweed, particularly kelp, can contain very large and variable amounts. Both insufficient and excessive iodine can disturb thyroid function.
Selenium
Selenium is part of proteins involved in thyroid-hormone metabolism and protection against oxidative damage. Eggs, grains and other foods contribute; plant-food content depends partly on growing conditions.[27]
Brazil nuts may contain substantial, variable amounts. They are not a precise daily dose. Excess selenium can damage hair and nails, the same features often used to advertise supplements.
Variety is useful; guessing large doses is less useful
A varied pattern spreads intake across foods and meals. If you remove a regular source—such as dairy—or rely on a very limited menu, identify what will replace the nutrients it supplied.
Choosing iodised salt within a suitable salt intake is different from increasing salt consumption to obtain iodine. A small dietary adjustment should fit the rest of the plan.
Iron and B12 deserve attention for different reasons
Iron: assess the cause of a shortfall
Iron is part of haemoglobin and myoglobin, proteins involved in oxygen transport and use. Legumes, tofu, seeds and fortified foods provide non-haem iron. Pairing them with vitamin-C-rich foods can improve absorption.[28]
Iron deficiency can occur before anaemia develops; anaemia also has causes other than iron deficiency. Menstrual blood loss, low intake, impaired absorption or other blood loss can be relevant. Ferritin helps assess stores but can rise with inflammation, so results need context.
Tiredness alone does not identify iron deficiency. Unnecessary iron can cause adverse effects, while treating a low result without considering its cause can leave the underlying problem unresolved.
B12: plan ahead of symptoms
Low B12 can affect blood cells and nerves, and neurological problems can occur without anaemia. Inadequate intake and impaired absorption are different problems that may need different treatment.[16]
For vegan diets, the German Nutrition Society recommends B12 supplementation alongside a well-planned diet. Fermented foods and unfortified nutritional yeast are not dependable substitutes for a verified source.[29]
Use assessment to answer a question
New or persistent fatigue, tingling, reduced exercise tolerance or other concerning changes deserve appropriate assessment. They have multiple possible explanations. Bring information about your usual diet and supplements so the assessment can connect symptoms, intake and relevant tests.
Bone health depends on a pattern of support
Bone is living tissue that is continually renewed. Adequate calcium contributes to its mineral structure, but a normal blood calcium result does not establish that dietary calcium intake or bone strength is adequate.[19]
Include dependable calcium sources regularly. When using plant alternatives, check fortification. Spinach contains calcium, but its oxalate content makes absorption relatively poor; it should not be your main calcium strategy.
Vitamin D needs vary with circumstances
Severe vitamin D deficiency can cause osteomalacia in adults and rickets in children. Osteoporosis is a different, multifactorial condition; vitamin D alone does not explain or treat every loss of bone strength.[6]
Season, latitude, skin characteristics and time outdoors affect skin production. There is no universal safe number of minutes in the sun that guarantees adequacy. Use local nutritional guidance and individual circumstances when planning food or supplements.
Excess supplemental vitamin D can raise blood calcium to harmful levels. The ability to buy a high-strength product does not establish a reason to take it.
Testing should have a purpose
The Endocrine Society's 2024 guideline advises against routine vitamin D screening in generally healthy adults without an established indication. This does not apply to every clinical situation or mean that dietary provision can be ignored.[30]
Food, suitable physical activity, recovery and any necessary medical care work together. A supplement should address its intended part of that picture.
What a food contains is only part of the story
Bioavailability describes how much of a nutrient becomes available for the body to use. The food matrix, nutrient form, meal composition and digestive health can influence it. This is one reason two foods with similar label values need not behave identically.
Use simple combinations
A lentil meal with peppers or broccoli brings iron and vitamin C together. A dressing containing some oil can accompany leafy vegetables. A calcium-fortified drink can add a dependable source to a breakfast that otherwise provides little calcium.
These examples are useful meal-building ideas, not rules requiring every food to be eaten in a perfect combination. Overall adequacy and repeatable habits remain the priority.
Preparation can change availability
Some plant compounds bind minerals. For zinc, soaking and fermentation can reduce the effect of phytate in certain foods.[24] This is not a reason to abandon legumes, seeds or whole grains: they also provide valuable nutrients.
Cooking can reduce some vitamins while making foods easier to eat and digest. Include different preparations according to preference and tolerance rather than assuming that raw food is always nutritionally superior.
Check what changed when you changed products
Two oat drinks may differ in calcium, B12, vitamin D and iodine. The same applies to yoghurts, breakfast cereals and nutritional yeast. “Plant-based,” “organic” or “natural” does not specify fortification.
Look for the named nutrients, amount per serving and realistic contribution to your day. Keep preparation and storage instructions in view. If digestive disease or surgery affects absorption, a food-content calculation alone may be insufficient.
Electrolyte balance is not the same as drinking more
Sodium and potassium help maintain electrical gradients across cell membranes; calcium is involved in muscle activation and signalling. These are normal physiological functions, not evidence that every workout requires an electrolyte supplement.
Replace losses without forcing excess fluid
Sweat losses vary with the person, activity and conditions. For prolonged exercise or substantial sweating, an individual plan may include sodium as well as fluid. Ordinary meals and water often cover less demanding activity.[31]
Drinking beyond the body's needs can dilute blood sodium and contribute to exercise-associated hyponatraemia. A sports drink or salt tablet does not make unlimited drinking safe. Neither thirst nor urine colour is a precise stand-alone measurement of electrolyte status.
Choose the drink for its purpose
Sports drinks commonly combine carbohydrate and fluid, and may supply useful sodium. A sugar-free electrolyte product can supply minerals while contributing little fuel. Check the amount in the actual prepared serving.[32]
Oral rehydration solutions, or ORS, have a different primary purpose: replacing fluid and salts lost through diarrhoeal illness. Their ingredient proportions are designed for that setting. Prepare a commercial ORS exactly as directed; an ordinary sports drink is not an equivalent formulation.[33]
Cramps do not identify a missing mineral
Exercise-associated cramps have multiple contributing factors, including fatigue and altered neuromuscular control. Research does not support explaining every cramp by dehydration or low sodium, potassium or magnesium.[34]
Review training demands, pacing, preparation and the circumstances of the episode. Repeated, unexplained or severe cramps deserve assessment rather than repeated trials of larger mineral doses.
Everyday salt advice and heavy sweat loss are different contexts
WHO's general adult recommendation is less than 2 g sodium per day, equivalent to less than 5 g salt across all foods.[23] This is public-health guidance, not an individual replacement calculation for a long event in heat.
A sport-specific plan should consider the actual demands and any medical advice. Sudden confusion, collapse or seizures during or after exercise require urgent medical assessment; do not assume that the answer is simply more water.
Activity calls for adequate nutrition, not automatic megadoses
Training can change food needs, sweat losses and the practical opportunities to eat. It does not create one universal “athlete dose” of every vitamin and mineral.
Start with enough food
A demanding programme combined with chronically inadequate energy intake can create health and performance problems. The IOC describes relative energy deficiency in sport as harmful effects associated with problematic low energy availability in female and male athletes.[35]
Taking a multivitamin does not replace the missing energy. Review meals, portions, recovery and training demands when fatigue, declining performance or recurrent injuries appear.
Direct attention where there is a reason
An endurance athlete with heavy menstrual bleeding, a person excluding major food groups, or someone with recurrent bone stress injuries may need a more focused assessment. The useful question is which need or risk has been identified.
The Australian Institute of Sport treats micronutrient supplements such as iron, calcium and vitamin D as products for specific situations and protocols, not blanket requirements for all active people.[32]
Separate food benefits from supplement promises
Vegetables, fruit, legumes and nuts remain useful foods. Their vitamin content does not mean that isolating a large amount of an antioxidant reproduces all the benefits of the diet.
When evaluating a supplement claim, ask who was studied, whether they were deficient, what amount was used and what improved. Correcting a deficiency and improving performance in a well-nourished athlete are different outcomes.
A sports dietitian can connect nutritional planning with training, food preferences and relevant clinical findings. The aim is a plan that supports the actual person doing the activity.
Some circumstances call for more deliberate planning
Pregnancy planning and pregnancy
Folic acid has a specific preventive role before and during early pregnancy. CDC guidance recommends 400 micrograms daily for women who could become pregnant to help prevent neural tube defects.[36] Individual circumstances may require a different prescribed plan; check local maternity guidance early.
Pregnancy changes several nutrient needs, but it does not mean that every vitamin or mineral should be doubled. Review existing products with the maternity-care team, particularly high-dose formulas and products containing preformed vitamin A.
Vegan diets and other exclusions
Plan reliable B12 supplementation for a vegan diet, and review calcium, iodine, iron, zinc and vitamin D provision. The DGE emphasises both supplementation of B12 and attention to potentially critical nutrients.[29]
An allergy or intolerance can require a similar replacement exercise. If a food disappears, identify what it supplied and choose suitable alternatives rather than assuming another product with the same culinary use has the same nutrition.
Age, appetite and absorption
Later life can bring changes in appetite, access to meals and absorption. Some older adults have difficulty absorbing food-bound B12.[16] A smaller appetite makes dependable meals and appropriate individual support particularly useful.
Persistent digestive problems, surgery affecting absorption, kidney disease and some medicines can also change the plan. These are reasons to connect dietary advice with care, rather than rely on a standard supplement bundle.
Practical help matters too: affordable groceries, suitable textures, help with preparation and enjoyable shared meals can make nutritional guidance possible to follow.
Build a routine with clear sources and purposeful supplements
A useful routine does not require memorising every nutrient table. Begin with what you actually eat, identify the gaps that matter and make the next step manageable.
-
Look at a representative few days.
Include busy days and rest days. Notice missing meals, limited variety and food groups that rarely appear.
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Name dependable sources.
Identify your usual calcium foods, iron-containing foods, vegetables, fruit, grains, legumes, nuts or seeds. Check B12 and iodine provision when your dietary pattern makes them less straightforward.
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Make one practical improvement.
Add a suitable fortified product, prepare a legume dish, keep frozen vegetables available or arrange a reliable lunch. Choose something you can repeat.
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Give each supplement a reason.
Record the nutrient, amount, purpose and review plan. Consider other products containing it, your medicines and any relevant professional guidance.
-
Review the result.
Ask whether intake is more dependable, symptoms need assessment or a prescribed course needs follow-up. Keep the plan responsive to changes in health and daily life.
Read across the products you use
A multivitamin, magnesium blend, energy drink and hair-and-nail formula can contain overlapping nutrients. Product names do not reveal the full contents. Add up the declared amounts of anything repeated rather than assessing each label in isolation.
EFSA upper limits are nutrient-specific and may apply to total intake or particular added forms. When no upper limit has been established, that may reflect limited data; it does not prove that unlimited intake is safe.[4]
Use food combinations that fit ordinary life
Examples include oats with a suitably fortified drink and fruit; lentils with buckwheat and peppers; yoghurt or a suitable alternative with nuts; or tofu with potatoes and broccoli. Their contribution depends on portions and product choices. These are meal ideas, not calculated complete menus.
Frozen vegetables, canned legumes and simple repeatable meals can reduce cost and preparation time. Variety can develop across a week; every plate does not need every nutrient.
Let tests answer an appropriate question
Testing is most useful when selected and interpreted in context. A clinician may connect symptoms, diet, health history and relevant measurements. Avoid treating a broad commercial nutrient panel as a complete map of health.
Keep supplements safely stored and labelled. If you are following treatment for a diagnosed deficiency, use the agreed dose and follow-up rather than adapting an educational reference range into your own treatment course.
Clear answers for everyday decisions
Do vitamins give me energy?
They provide no calories. Some help the body use energy from food; more vitamins do not replace adequate meals or guarantee greater energy.
Are water-soluble vitamins always safe in large amounts?
No. B6 can damage nerves at excessive sustained intakes, and biotin can interfere with certain laboratory tests. Solubility is not a safety guarantee.
Does a colourful diet cover everything?
Colour and variety help, but they do not guarantee B12, iodine, calcium or vitamin D provision. Check the nutrients your pattern might supply less reliably.
Should I take iron whenever I feel tired?
No. Fatigue has many causes. Iron supplementation should address an appropriate indication, with attention to why iron is low when deficiency is found.
Does every cramp mean I need magnesium?
No. Exercise cramps have several possible contributors, including fatigue. Repeated or unexplained episodes deserve a broader assessment.
Do I need an electrolyte drink for every workout?
No. Consider duration, conditions, losses and meals. Longer or demanding activity may justify a specific fluid, sodium and fuel plan.
Is a sports drink the same as oral rehydration solution?
No. They have different formulations and primary uses. Use properly prepared ORS when that is the appropriate treatment for illness-related fluid loss.
Is 100% of the label reference value a personal prescription?
No. It is a standard comparison. Your circumstances, total diet, serving size and the purpose of the product still matter.
Should all healthy adults have routine vitamin D blood tests?
No. Routine screening is not recommended for generally healthy adults without an established indication. Testing can still be appropriate in specific clinical circumstances.
Can supplements replace a varied diet?
They can supply specific nutrients when useful. They cannot supply everything provided by adequate meals, including their energy, protein, fibre and enjoyment.
Sources and scope
Evidence and guidance checked: 5 September 2026. The references link to official nutrient information, European reference-value assessments, public-health guidance and professional research.
This is an adult educational guide. Food examples are illustrative, not calculated menus. Intake references are not diagnostic thresholds or treatment instructions; individual care and local guidance can require a different approach.
- World Health Organization. Micronutrients. Public-health overview; accessed September 2026.Definition and importance of vitamins and minerals. Return to text ↑
- European Food Safety Authority. Dietary reference values. Reference-value overview; reviewed August 2024.Purpose and interpretation of population reference values. Not personal treatment targets. Return to text ↑
- European Parliament and Council. Regulation (EU) No 1169/2011: food information to consumers. Articles 32–33 and Annex XIII.Reference quantities and nutrient reference values used in food labelling. Return to text ↑
- European Food Safety Authority. Overview on Tolerable Upper Intake Levels. Summary report, version 11, August 2025.Nutrient-specific upper limits and their scope. A limit is not an intake target. Return to text ↑
- NIH Office of Dietary Supplements. Vitamin A and Carotenoids: Consumer Fact Sheet. Official nutrient information; accessed September 2026.Functions, food sources and differences between preformed vitamin A and carotenoid supplements. Return to text ↑
- NIH Office of Dietary Supplements. Vitamin D: Fact Sheet for Health Professionals. Official nutrient information; accessed September 2026.Food and skin sources, skeletal roles, deficiency and excessive supplemental intake. Return to text ↑
- NIH Office of Dietary Supplements. Vitamin E: Fact Sheet for Health Professionals. Official nutrient information; accessed September 2026.Antioxidant function, food sources and risks from high supplemental intake. Return to text ↑
- NIH Office of Dietary Supplements. Vitamin K: Fact Sheet for Health Professionals. Official nutrient information; accessed September 2026.K1 and K2 sources and interactions with vitamin K antagonist medicines. Return to text ↑
- NIH Office of Dietary Supplements. Thiamin: Fact Sheet for Health Professionals. Official nutrient information; accessed September 2026.B1 functions and food sources. Return to text ↑
- NIH Office of Dietary Supplements. Riboflavin: Fact Sheet for Health Professionals. Official nutrient information; accessed September 2026.B2 coenzymes and food sources. Return to text ↑
- NIH Office of Dietary Supplements. Niacin: Fact Sheet for Health Professionals. Official nutrient information; accessed September 2026.NAD and NADP, food sources and conversion from tryptophan. Return to text ↑
- NIH Office of Dietary Supplements. Pantothenic Acid: Fact Sheet for Health Professionals. Official nutrient information; accessed September 2026.Coenzyme A and dietary sources of B5. Return to text ↑
- NIH Office of Dietary Supplements. Vitamin B6: Fact Sheet for Health Professionals. Official nutrient information; accessed September 2026.Metabolic functions and food sources. European upper-limit advice is cited separately. Return to text ↑
- NIH Office of Dietary Supplements. Biotin: Fact Sheet for Health Professionals. Official nutrient information; accessed September 2026.Enzyme functions, food sources and interference with some laboratory tests. Return to text ↑
- NIH Office of Dietary Supplements. Folate: Fact Sheet for Health Professionals. Official nutrient information; accessed September 2026.Cell division, food folates and folic acid in fortified foods or supplements. Return to text ↑
- NIH Office of Dietary Supplements. Vitamin B12: Fact Sheet for Health Professionals. Official nutrient information; accessed September 2026.Blood and nerve functions, long-term stores, dietary sources and absorption problems. Return to text ↑
- EFSA NDA Panel. Scientific opinion on the tolerable upper intake level for vitamin B6. EFSA Journal. 2023;21(5):8006. DOI: 10.2903/j.efsa.2023.8006.Adult upper limit of 12 mg/day, derived with peripheral neuropathy as the critical adverse effect. Return to text ↑
- NIH Office of Dietary Supplements. Vitamin C: Consumer Fact Sheet. Official nutrient information; accessed September 2026.Collagen, food sources, iron absorption, preparation and excessive intake. Return to text ↑
- NIH Office of Dietary Supplements. Calcium: Fact Sheet for Health Professionals. Official nutrient information; accessed September 2026.Skeletal and physiological roles, food sources and absorption differences. Return to text ↑
- NIH Office of Dietary Supplements. Phosphorus: Fact Sheet for Health Professionals. Official nutrient information; accessed September 2026.Bone, membranes, ATP and the relevance of kidney disease. Return to text ↑
- NIH Office of Dietary Supplements. Magnesium: Fact Sheet for Health Professionals. Official nutrient information; accessed September 2026.Metabolic roles, foods, elemental amounts and supplement-related adverse effects. Return to text ↑
- NIH Office of Dietary Supplements. Potassium: Fact Sheet for Health Professionals. Official nutrient information; accessed September 2026.Cellular and fluid functions, foods, kidney handling and medication-related considerations. Return to text ↑
- World Health Organization. Sodium reduction. Public-health guidance, 11 May 2026.General population guidance on sodium and salt; not an individual exercise-replacement protocol. Return to text ↑
- NIH Office of Dietary Supplements. Zinc: Fact Sheet for Health Professionals. Official nutrient information; accessed September 2026.Functions, plant-food bioavailability and copper depletion from excessive zinc. Return to text ↑
- NIH Office of Dietary Supplements. Copper: Fact Sheet for Health Professionals. Official nutrient information; accessed September 2026.Enzyme functions, iron metabolism and food sources. Return to text ↑
- NIH Office of Dietary Supplements. Iodine: Fact Sheet for Health Professionals. Official nutrient information; accessed September 2026.Thyroid function, variable food sources, iodised salt and seaweed-related excess. Return to text ↑
- NIH Office of Dietary Supplements. Selenium: Fact Sheet for Health Professionals. Official nutrient information; accessed September 2026.Selenoproteins, variable food content and excessive intake. Return to text ↑
- NIH Office of Dietary Supplements. Iron: Fact Sheet for Health Professionals. Official nutrient information; accessed September 2026.Oxygen-related functions, iron deficiency, absorption and interpretation of ferritin. Return to text ↑
- German Nutrition Society. Update of the DGE position on vegan diet. Ernährungs Umschau International. 2024;71(7):60–84.B12 supplementation and potentially critical nutrients in vegan diets. Return to text ↑
- Endocrine Society. Vitamin D for the Prevention of Disease. Clinical practice guideline, 2024.Routine screening is discouraged in healthy adults without an established indication; individual clinical needs remain relevant. Return to text ↑
- National Athletic Trainers’ Association. Fluid replacement guidance for physically active people. Official position-statement summary, 6 October 2017.Page title shortened. Individual hydration planning and risks of excessive fluid intake. Return to text ↑
- Australian Institute of Sport. Group A: sports foods and medical supplements. Sports Supplement Framework; accessed September 2026.Specified uses of sports drinks and medical supplements; classification is not a recommendation for everyone. Return to text ↑
- Government of Canada. Oral rehydration solutions. Public-health guidance, 15 May 2024.Purpose and preparation of ORS for diarrhoeal illness. Sports drinks have a different formulation. Return to text ↑
- Miller KC, McDermott BP, Yeargin SW, et al. Exercise-associated muscle cramps: pathophysiology, treatment and prevention. Journal of Athletic Training. 2022;57(1):5–15. DOI: 10.4085/1062-6050-0696.20.Title shortened. Evidence review of multiple contributors to cramps and individual prevention strategies. Return to text ↑
- Mountjoy M, Ackerman KE, Bailey DM, et al. 2023 IOC consensus statement on Relative Energy Deficiency in Sport. British Journal of Sports Medicine. 2023;57:1073–1097. DOI: 10.1136/bjsports-2023-106994.Title shortened. Health and performance effects of problematic low energy availability in female and male athletes. Return to text ↑
- Centers for Disease Control and Prevention. About Folic Acid. Public-health guidance, 15 July 2026.400 micrograms daily for women who could become pregnant; individual higher-risk plans require clinical guidance. Return to text ↑