Nutrition
Vitamins, minerals and supplements: official reference intakes, upper limits and what clinical trials actually show.
- Do Multivitamins Work? What the Large Trials Actually Show
What randomised trials (Physicians' Health Study II, COSMOS) and the US Preventive Services Task Force found about multivitamins for cancer, heart disease, memory and lifespan.
- Folate and Folic Acid: Pregnancy, Reference Intakes and Upper Limits
Folate versus folic acid, dietary folate equivalents, reference intakes, the pregnancy recommendation to prevent neural tube defects, fortification and the upper limit.
- Food First: How to Read Reference Intakes, RDAs and Label Percentages
RDA, EAR, AI, PRI, RNI and UL explained; why US, EU and UK values differ; and how to read %DV and %NRV on food and supplement labels.
- How to Choose a Multivitamin: A Label-Reading Guide Without Brands
A practical, brand-free guide to choosing a multivitamin: whether you need one, reading Supplement Facts and NRV labels, upper limits, iron, vitamin A, third-party testing (USP, NSF).
- Iodine: The Overlooked Mineral in Pregnancy and Plant-Based Diets
Iodine reference intakes, why salt iodisation matters, sources in countries without it, risks for pregnancy and vegans, seaweed and kelp warnings, and the upper limit.
- Iron: Needs, Anaemia, Absorption and Why Supplements Need Care
Iron reference intakes for men, women and pregnancy, haem and non-haem iron, iron deficiency anaemia, testing, the upper limit and the risks of unneeded supplements.
- Magnesium: Needs, Food Sources, and the Evidence on Sleep and Cramps
Magnesium reference intakes, food sources, who is at risk of low levels, what trials show for cramps, blood pressure and sleep, and the 350 mg supplement upper limit.
- Omega-3 Fatty Acids: Not a Vitamin, and What Fish Oil Trials Show
Omega-3s (ALA, EPA, DHA) are essential fats, not vitamins. Reference intakes, fish advice, and what VITAL, REDUCE-IT and Cochrane reviews found about supplements.
- Upper Limits: When Vitamin and Mineral Supplements Can Harm
What tolerable upper intake levels are, a US and EU table of upper limits for common vitamins and minerals, the nutrients most often taken in excess, and drug interactions.
- Vitamin B12: Needs, Deficiency Risks for Vegans and Older Adults
Vitamin B12 reference intakes, food sources, who is at risk of deficiency (vegans, older adults, pernicious anaemia, metformin), symptoms and how it is diagnosed.
- Vitamin C: Daily Needs, Colds, and What High Doses Really Do
Vitamin C reference intakes, food sources, the Cochrane evidence on colds, who is at risk of deficiency, the 2,000 mg upper limit and the kidney stone question.
- Vitamin D: How Much You Need, Who Is Short, and What Trials Show
Vitamin D reference intakes (US, EU, UK), upper limits, blood levels, who is at risk of deficiency, and what large trials such as VITAL found about supplements.
- Who May Need Supplements: Pregnancy, Babies, Vegans and Older Adults
The groups for whom health authorities recommend specific supplements: pregnancy, infants and young children, vegans, older adults, people with little sun exposure and medical conditions.
