Nutrition guide
Vitamins and multivitamins.
How vitamins work, when supplements can help, and why a broad multivitamin is not a universal health intervention.
4 min read
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Vitamins & minerals
Explore related questions, products and evidence in this collection.
Vitamins & minerals
Explore related questions, products and evidence in this collection.
Nutrition guide
Vitamin D.
What vitamin D does for bone health, what supplementation trials do not show, and why more is not automatically better.
10 min read
Nutrition guide
Magnesium.
A mineral involved in hundreds of body processes, with supplement claims that need to be separated from deficiency treatment and medication use.
8 min read
Practical supplement guide
Should you take vitamins with food?
How food, formulation and other medicines can change the answer, with examples of vitamin D, iron and calcium.
4 min read
Supplement storage guide
How should vitamins and mineral supplements be stored?
Sunlight, bathrooms, refrigeration and expiry dates depend on the product in the bottle.
5 min read
Nutrition guide
Folate and folic acid.
What vitamin B9 does, how folate and folic acid differ, and why timing matters in pregnancy.
5 min read
Nutrition guide
Vitamin B12.
Why B12 matters for nerves and blood cells, where it comes from, and why absorption matters.
9 min read
Nutrition guide
Vitamin B1 (thiamin).
What this B vitamin does, where it is found and how to interpret supplement claims.
3 min read
Nutrition guide
Vitamin B2 (riboflavin).
What this B vitamin does, where it is found and how to interpret supplement claims.
3 min read
Nutrition guide
Vitamin B3 (niacin).
What this B vitamin does, where it is found and how to interpret supplement claims.
5 min read
Nutrition guide
Vitamin B5 (pantothenic acid).
What this B vitamin does, where it is found and how to interpret supplement claims.
3 min read
Nutrition guide
Vitamin B6: food, mood claims and nerve safety
How to understand B6 in foods and supplements, what mood research actually found, and why labels can add up.
7 min read
Nutrition guide
Biotin (vitamin B7).
What this B vitamin does, where it is found and how to interpret supplement claims.
4 min read
Nutrition guide
Iron: food, low iron, anaemia and supplements
Why iron matters, what a low result can mean and how to weigh supplements and their risks.
13 min read
Nutrition guide
Zinc.
What this mineral does, food sources and how to interpret supplement claims.
5 min read
Nutrition guide
Iodine.
What this mineral does, food sources and how to interpret supplement claims.
3 min read
Nutrition guide
Selenium.
What this mineral does, food sources and how to interpret supplement claims.
5 min read
Nutrition guide
Copper.
What this mineral does, food sources and how to interpret supplement claims.
4 min read
Nutrition guide
Vitamin E: food, supplements and cancer evidence
What vitamin E does, why food and high-dose supplements are different, and what the SELECT trial found.
4 min read
Nutrition guide
Vitamin C and colds: what does the evidence show?
Food, deficiency and the difference between preventing a cold and shortening its symptoms.
4 min read
Nutrition guide
Vitamin A: forms, food and supplement risks
Explore the forms in food and supplements, what research shows, and the questions that matter in everyday use.
7 min read
Nutrition guide
Vitamin A in food: retinol, beta-carotene and absorption
Follow the different paths from animal foods and plants to the vitamin A your body uses.
5 min read
Nutrition guide
How to read vitamin A labels and spot overlapping supplements
Retinol, beta-carotene, RAE, IU and percentages explained with a worked label.
7 min read
Nutrition guide
Vitamin A in pregnancy and planning: food, supplements and retinoids
Why the form matters, how to read prenatal labels, and when a retinoid medicine needs urgent attention.
6 min read
Nutrition guide
Vitamin A interactions: orlistat, retinoids and other supplements
Why one medicine can reduce absorption while other products may increase the risk of excess.
6 min read
Nutrition guide
Too much vitamin A: accidental exposure, symptoms and excess
Why one possible overdose and repeated high intake need different questions—and where to get help.
5 min read
Nutrition guide
Vitamin A and night vision: deficiency, eye health and what to check
Why vitamin A matters in dim light, what else can affect sight and how deficiency is assessed.
5 min read
Evidence guide
AREDS and AREDS2: do eye supplements help macular degeneration?
What the two trials found, who they studied and why eye-supplement labels need a closer look.
7 min read
Evidence guide
Beta-carotene, smoking and cancer: what two trials found
ATBC and CARET tested supplements, not vegetables. Here is what they found and what the numbers mean.
5 min read
Nutrition guide
Vitamin A for children: food, deficiency and measles
Why children need vitamin A, why guidance differs and when a child needs medical help.
6 min read
Nutrition guide
Vitamin A, retinol and skin: food, skincare and retinoid medicines
What differs between a vitamin supplement, a retinol serum and retinoid medicines—and what the studies show.
5 min read
Nutrition guide
Vitamin A and immunity: do supplements prevent infections?
What the immune system needs, why deficiency matters and what infection studies can—and cannot—tell us.
4 min read
Question guide
How vitamin A moves through your body
Follow the different routes from a carrot or cod liver oil to the intestine, liver, eye and other tissues.
5 min read
Question guide
Can you boost your immune system with peptides or vitamins?
What immune support can mean, what everyday habits and vaccines do, and how to judge product claims.
3 min read
Practical health guide
Vitamin B6, B12 and nerve symptoms: too much or too little?
Why deficiency and supplement excess can cause similar symptoms, and what to take to a healthcare appointment.
4 min read
Practical health guide
Nitrous oxide, vitamin B12 and nerve symptoms: what is the connection?
Why tingling or weakness after laughing gas deserves attention, even when a B12 result looks normal.
3 min read
Practical health guide
Vitamin B12 tests: what do B12, MMA and homocysteine results mean?
Why a blood number is one part of the story, and why symptoms, supplements and the reason for testing matter.
5 min read