Phosphorus
What it does and why you need it
Phosphorus is the second most abundant mineral in the body after calcium. About 85 per cent is in bone, paired with calcium in the hydroxyapatite mineral that gives bone its strength. The remainder sits in soft tissue, in cell membranes (phospholipids), in DNA and RNA, and in the ATP that powers every cell's metabolism. Most people meet the requirement from food without thinking about it.
Best food sources
Values per 100g from USDA SR Legacy and McCance and Widdowson 7th edition; the site's food entries currently store macros only.
| Food | Typical UK portion | Phosphorus per portion | % adult RNI |
|---|---|---|---|
| Cheddar cheese | 30g | around 160mg | 29% |
| Salmon, cooked | 100g | around 250mg | 45% |
| Beef, lean cut, cooked | 100g | around 175mg | 32% |
| Milk | 200ml | around 190mg | 35% |
| Egg, whole | One medium, around 50g | around 100mg | 18% |
| Lentils, cooked | 150g | around 270mg | 49% |
| Peanuts | 30g | around 115mg | 21% |
UK reference intake by age and sex
UK Reference Nutrient Intake (RNI) for phosphorus is set by SACN (1991). UK RNI matches calcium RNI broadly (the body's bone mineral needs both).
| Group | Daily phosphorus (mg) |
|---|---|
| Babies, 0 to 12 months | 400 |
| Children, 1 to 3 years | 270 |
| Children, 4 to 6 years | 350 |
| Children, 7 to 10 years | 450 |
| Adolescents, 11 to 18 years | 775 |
| Adults, 19 years and over | 550 |
| Pregnancy | No increment |
| Breastfeeding | 990 (an increment of 440) |
Deficiency signs and who is at risk
Phosphorus deficiency from diet is essentially absent in the UK. Low blood phosphate has medical causes (severe alcohol withdrawal, certain antacid use, refeeding syndrome after starvation, some kidney conditions) rather than diet.
Signs of low blood phosphate include muscle weakness, bone pain, fatigue, and irritability; severe cases cause heart and respiratory muscle weakness and require hospital treatment.
Too much: safe upper limit
Phosphorus from food is not a realistic concern for healthy adults.
NHS supplement guidance: taking 250mg or less of phosphorus from supplements daily is unlikely to cause any harm. Very high intakes (especially from phosphate-rich soft drinks combined with low calcium intake) have been linked in observational studies to reduced bone density.
People with chronic kidney disease need to restrict phosphorus, on personalised advice from a renal team.
Supplements and UK guidance
Routine phosphorus supplementation is not needed and is essentially never recommended for healthy adults. The dietary supply is generous and reliable.
Related
Sources and references
- NHS. Vitamins and minerals: Others. nhs.uk/conditions/vitamins-and-minerals/others.
- SACN. Dietary Reference Values for Food Energy and Nutrients for the United Kingdom. Department of Health Report 41 (1991).
- Public Health England. McCance and Widdowson's The Composition of Foods, 7th summary edition (2015).
This page is reference information for UK shoppers. It is not medical advice.