Research
Nutrient Needs by Life Stage: A UK Reference Table for Women
UK Reference Nutrient Intakes (RNIs) for women change by life stage: iron requirements fall by 41% after menopause once periods stop, calcium and zinc rise while breastfeeding, and vitamin D is the one nutrient that stays fixed at 10 micrograms a day throughout. This table consolidates 11 nutrients across teens, 19 to 50, 50 plus, pregnancy and breastfeeding from the UK's official Dietary Reference Values, so the guidance scattered across individual supplement pages sits in one place. Information only, not medical advice; speak to a GP or pharmacist before changing what you take.
Figures as of 2026-08-04. Primary source: Department of Health, Dietary Reference Values for Food Energy and Nutrients for the United Kingdom (COMA, 1991); SACN, Vitamin D and Health (2016).
Reference Nutrient Intakes by life stage
| Nutrient | Teens (11-18) | 19-50 | 50+ | Pregnancy | Breastfeeding |
|---|---|---|---|---|---|
| Iron (mg/day) | 14.8 | 14.8 | 8.7 | 14.8* | 14.8* |
| Calcium (mg/day) | 800 | 700 | 700 | 700* | 1,250 |
| Magnesium (mg/day) | 300 | 270 | 270 | 270* | 320 |
| Zinc (mg/day) | 7 | 7 | 7 | 7* | 9.5–13.0 |
| Iodine (µg/day) | 140 | 140 | 140 | 140* | 140* |
| Folate (µg/day (dietary)) | 200 | 200 | 200 | 300 | 260 |
| Vitamin B12 (µg/day) | 1.5 | 1.5 | 1.5 | 1.5* | 2.0 |
| Vitamin C (mg/day) | 40 | 40 | 40 | 50 | 70 |
| Vitamin A (µg/day (retinol equivalent)) | 600 | 600 | 600 | 700 | 950 |
| Vitamin D (µg/day) | 10 | 10 | 10 | 10 | 10 |
| Selenium (µg/day) | 60 | 60 | 60 | 60* | 75 |
* marks a life stage where the 1991 Dietary Reference Values set no separate RNI (the 19-50 figure applies unchanged). Where a range is shown for breastfeeding, it reflects the 0-4 month and 4+ month figures differing.
What changes, and why
Iron: Drops by 41% at 50+ once monthly periods stop. No separate pregnancy/breastfeeding RNI is set in the 1991 values (marked *); the NHS notes many pregnant women are still advised iron by a midwife based on blood tests, not this table alone.
Calcium: Breastfeeding adds 550 mg/day to cover milk output; pregnancy has no separate RNI (marked *, assumed met by increased absorption efficiency).
Zinc: Breastfeeding adds 6.0 mg/day in the first 4 months, 2.5 mg/day after.
Iodine: The 1991 UK values set no separate pregnancy/breastfeeding RNI for iodine (marked *). This is a known gap: newer international bodies (WHO among them) recommend higher intakes in pregnancy and breastfeeding than the UK 1991 figure reflects. Discuss iodine intake with a GP or midwife rather than relying on this table alone.
Folate: This is DIETARY folate, not the separate NHS folic acid SUPPLEMENT advice: 400 µg/day before conception and until 12 weeks of pregnancy, to reduce the risk of neural tube defects. The two figures measure different things and are not interchangeable.
Vitamin C: The pregnancy +10 mg only applies in the last trimester.
Vitamin A: The NHS advises pregnant women avoid supplements containing vitamin A (retinol) and liver, as high intakes are linked to harm to the baby, regardless of this RNI figure. See NHS pregnancy vitamins guidance.
Vitamin D: Fixed at 10 µg/day across every life stage since SACN's 2016 revision, including pregnancy and breastfeeding: the one nutrient on this table where the target does not change.
NHS pregnancy supplement advice (separate from the RNI table above)
The NHS advises a 400 microgram folic acid supplement before conception until 12 weeks of pregnancy, and a 10 microgram vitamin D supplement throughout pregnancy and while breastfeeding. These are specific supplement recommendations, not the dietary RNI figures in the table above, and apply regardless of diet.
Common questions
Why does the iron requirement drop so much after 50?
The UK Reference Nutrient Intake (RNI) for iron is 14.8 mg/day for women aged 19 to 50, set that high specifically to cover average menstrual blood loss. Once periods stop at menopause, the figure drops to 8.7 mg/day, the same as the adult male RNI. It's one of the clearest examples of a nutrient target that is genuinely tied to life stage, not just age.
Is the RNI the same as "how much I should take in a supplement"?
No. The RNI is a population planning figure covering total intake from food AND any supplements, set to meet the needs of 97.5% of a group, not a personal target. Most women get some of these nutrients from diet already. See our cost-per-effective-dose tools to check what a specific product actually provides against these figures.
Why does folate show two different numbers for pregnancy?
They measure different things. The 300 µg/day figure on this table is the dietary folate RNI (COMA 1991), covering folate from food and fortified sources across pregnancy. The separate, better-known NHS advice is a 400 microgram FOLIC ACID SUPPLEMENT specifically before conception and until 12 weeks of pregnancy, aimed at reducing neural tube defect risk. Both are correct; they are not interchangeable, and the supplement advice is time-limited where the dietary RNI is not.
Do these figures apply to vegans and vegetarians?
The RNIs are set for the whole population regardless of diet, so the target amount is the same. What changes is how easily a diet meets it: iron and zinc from plant sources are less readily absorbed than from meat, and B12 has no reliable plant source, which is why NHS guidance specifically flags B12 supplementation for anyone on a vegan diet. The target number here doesn't change; the practical route to it does.
Methodology and sources
Every figure in the table traces to the Department of Health's 1991 Dietary Reference Values (set by COMA, the Committee on Medical Aspects of Food and Nutrition Policy), the standing UK reference since no full re-issue has followed. The one exception is vitamin D, superseded fleet-wide by SACN's 2016 Vitamin D and Health report, which set a single 10 microgram RNI for everyone over one year old, including pregnancy and breastfeeding. Figures are cross-checked against the British Nutrition Foundation's own consolidated summary of the same two documents (reviewed May 2021).
What this table is not: a personal recommendation, a substitute for a blood test, or an upper safe limit (the RNI is a target, not a ceiling). Anyone with a diagnosed deficiency, on medication, pregnant, or with an existing health condition should get personal guidance from a GP, midwife or pharmacist rather than reading this table as an instruction.
Primary source: Department of Health, Dietary Reference Values for Food Energy and Nutrients for the United Kingdom (COMA, 1991); SACN, Vitamin D and Health (2016).
Cite this table
Source: Her Vitals, Nutrient Needs by Life Stage: A UK Reference Table for Women, https://hervitals.co.uk/research/nutrient-needs-by-life-stage-uk/ (accessed 2026-08-04). Read more
See the individual pillar pages for iron, magnesium and vitamin D, our pregnancy supplements guide, and the perimenopause and menopause guide for how these targets apply in practice. The free supplement tools let you check a specific product's dose against these figures.
Editor, Her Vitals
Oliver leads Her Vitals's editorial coverage of women's life-stage health and supplements. He curates and reviews existing branded products across trying to conceive, pregnancy, postnatal, perimenopause, menopause and the senior years, weighing what the evidence supports against guidance from bodies such as EFSA, the NHS and NICE, and is clear that the content is information rather than medical advice.
Last reviewed: 4 August 2026
Reviewed by Oliver Mackman, Editor. Editorial review against published guidance; not a clinical review.