Vitamin deficiency statistics vary sharply by nutrient, age group, measurement threshold, geography, and survey year. Recent UK data show vitamin D deficiency ranging from 10% among children aged 4–10 to 23% among 11–18-year-olds, while U.S. estimates for vitamin B12 deficiency are generally lower when stricter biomarker cutoffs are used. Worldwide, vitamin A deficiency remains a major concern for young children in low- and middle-income countries.
Contents
- Vitamin D in the UK
- Seasonal and socioeconomic differences
- Folate status in the UK
- Vitamin B12 in U.S. adults
- Vitamin A worldwide and in the United States
- Other U.S. biomarker estimates
- Risk of multiple deficiencies
Vitamin D in the UK
The UK National Diet and Nutrition Survey report for 2019–2023 defines vitamin D deficiency as serum 25-hydroxyvitamin D below 25 nmol/L. Using that threshold, prevalence differed substantially by age:
| UK group | Below 25 nmol/L | Measurement period |
|---|---|---|
| Children aged 4–10 | 10% | 2019–2023 |
| Children aged 11–18 | 23% | 2019–2023 |
| Adults aged 19–64 | 18% | 2019–2023 |
| Adults aged 65 and over | 12% | 2019–2023 |
The highest estimate in this comparison was among children aged 11–18: 23% had serum 25-hydroxyvitamin D below the UK deficiency threshold. The estimate was 10% for children aged 4–10, 18% for adults aged 19–64, and 12% for adults aged 65 and over. These figures describe measured biomarker status during 2019–2023; they are not a diagnosis rate or a count of people treated for deficiency.
Among adults aged 19–64, deficiency prevalence appeared to be 3 percentage points higher in men than women. The report notes that this difference was not statistically tested, so it should be treated as an observed survey difference rather than evidence of a confirmed sex disparity.
The same UK report identifies serum 25-hydroxyvitamin D below 25 nmol/L as the deficiency threshold and records the government recommendation that everyone take 10 micrograms of vitamin D daily from October through March. The recommendation is a public-health policy measure, whereas the prevalence estimates above are biomarker measurements.
Source: National Diet and Nutrition Survey 2019 to 2023: report.
Seasonal and socioeconomic differences
Vitamin D status in the UK also changed with season. Across UK age and sex groups aged 11 years and over, the share below 25 nmol/L was 21% to 38% in January–March. In July–September, the corresponding share fell to 0% to 10%. These are ranges across groups, not a single national estimate for every person aged 11 and over.
The seasonal contrast matters when comparing surveys or individual results. A January–March estimate and a July–September estimate can describe different points in the same annual cycle, even when the age and sex categories are otherwise similar. The figures do not establish that season alone caused each individual difference, but they show a consistent pattern of lower measured status in the first quarter than in the third quarter across the reported groups.
Socioeconomic differences were also visible among English adults aged 19–64. In the most deprived deprivation quintile, 34% had vitamin D below 25 nmol/L. The other four deprivation quintiles ranged from 9% to 17% below that threshold. The gap between the most deprived quintile and the highest value reported for the other four quintiles was at least 17 percentage points.
Household income showed a related association with measured vitamin D status. Among UK adults aged 19–64, vitamin D status increased by 1 nmol/L for every £10,000 increase in equivalised household income. Among UK women aged 19–64, the reported increase was 2 nmol/L for every £10,000 increase. These are associations in the survey data, not evidence that a specific income change directly causes a specific biomarker change.
Source: National Diet and Nutrition Survey 2019 to 2023: report.
Folate status in the UK
The UK survey used more than one folate measure and threshold, so the results should not be combined as though they represented one definition of deficiency. Red-blood-cell folate below 305 nmol/L was the deficiency threshold for the following estimates from 2019–2023:
- 12% of children aged 11–18 were below 305 nmol/L.
- 4% of adults aged 19–64 were below 305 nmol/L.
- 7% of women aged 16–49 were below 305 nmol/L.
- Among children aged 11–18, 17% of girls and 7% of boys were below 305 nmol/L.
The survey also reported a higher red-blood-cell folate threshold associated with increased neural-tube-defect risk. At below 748 nmol/L, 83% of UK women aged 16–49 were below the threshold. This is a risk-associated population threshold, not the same as the clinical deficiency threshold of 305 nmol/L.
Serum folate produced another set of results. Using serum folate below 7 nmol/L as the clinical deficiency threshold, 8% of children aged 4–10, 24% of children aged 11–18, 14% of adults aged 19–64, and 7% of adults aged 65 and over were below the threshold. The 24% estimate among 11–18-year-olds was the highest in this serum-folate comparison.
Because red-blood-cell folate and serum folate reflect different measurements, their percentages are not interchangeable. The results are most useful when each value is read with its specimen type, threshold, age group, and 2019–2023 measurement period.
Source: National Diet and Nutrition Survey 2019 to 2023: report.
Vitamin B12 in U.S. adults
The U.S. National Health and Nutrition Examination Survey (NHANES) estimates show why vitamin B12 statistics depend heavily on the cutoff used. In NHANES 2007–2018, approximately 3.6% of U.S. adults aged 19 and over had vitamin B12 deficiency below 200 pg/mL (148 pmol/L). Among adults aged 60 and over, the estimate was approximately 3.7%.
At the broader insufficiency cutoff of below 300 pg/mL (221 pmol/L), approximately 12.5% of adults aged 19 and over and 12.3% of adults aged 60 and over were below the threshold. The difference between the deficiency and insufficiency estimates illustrates why two credible percentages can describe the same population without measuring the same condition.
Earlier NHANES 1999–2004 data reported that 3% of U.S. adults aged 19 and over had serum B12 below 200 pg/mL, while 26% were below 350 pg/mL. These earlier figures should be kept separate from the 2007–2018 estimates because they use a different survey period and, for the broader result, a different cutoff.
The source also summarizes studies using other biomarkers and thresholds. Approximately 21% of U.S. adults older than 60 had an abnormal result on at least one vitamin B12 biomarker in one cited analysis. Reported deficiency among community-dwelling older adults ranged from 3% to 43%, depending on the serum cutoff used. In a cited study of older adults entering long-term care, 14% were below 211 pg/mL (156 pmol/L), while 38% were below 407 pg/mL (300 pmol/L).
The long-term-care figures are from a cited study rather than a national estimate, and the source does not specify a measurement period for those cited results. They should not be generalized to all older adults in the United States.
Source: Vitamin B12 – Health Professional Fact Sheet.
Vitamin A worldwide and in the United States
Vitamin A deficiency has a markedly different geographic pattern. A pooled analysis estimated that 29% of children aged 6 months to 5 years across 138 low- and middle-income countries had vitamin A deficiency in 2013. The estimate was 48% in sub-Saharan Africa and 44% in South Asia. These are estimates for young children in the specified regions and year, not current global measurements for every age group.
Among pregnant women in low-income countries, vitamin A deficiency was estimated at 10% to 20%; the source gives no single measurement year for this cited estimate. For child deaths in low- and middle-income countries during 2013, vitamin A deficiency was estimated to contribute to 94,500 deaths from diarrhea and 11,200 deaths from measles. More than 95% of deaths attributable to vitamin A deficiency occurred in sub-Saharan Africa and Asia.
The U.S. picture was substantially lower in the cited national biomarker data. Less than 1% of the U.S. population had serum retinol below 20 mcg/dL, the indicator used for vitamin A deficiency, in NHANES 2003–2006. The low U.S. estimate and the much higher regional estimates for children in sub-Saharan Africa and South Asia describe different populations, years, and public-health contexts.
Source: Vitamin A and Carotenoids – Health Professional Fact Sheet.
Other U.S. biomarker estimates
The CDC’s Second National Report on Biochemical Indicators of Diet and Nutrition in the U.S. Population 2012 Executive Summary reported several deficiency estimates from NHANES biomarker data. The survey periods and age ranges differ by nutrient:
| Nutrient and measure | Population | Prevalence | Period |
|---|---|---|---|
| Vitamin B6, serum pyridoxal-5’-phosphate below 20 nmol/L | U.S. persons aged 1+ | 10.5% | NHANES 2003–2006 |
| Vitamin D, serum 25-hydroxyvitamin D below 30 nmol/L | U.S. persons aged 1+ | 8.1% | NHANES 2003–2006 |
| Vitamin C, serum ascorbic acid below 11.4 µmol/L | U.S. persons aged 6+ | 6% | NHANES 2003–2006 |
| Vitamin B12, serum cobalamin below 200 pg/mL | U.S. persons aged over 1 | 2% | NHANES 2003–2006 |
| Vitamin A, serum retinol below 20 µg/dL | U.S. persons aged 6+ | Below 1% | NHANES 2003–2006 |
Within the same vitamin B12 summary, children and adolescents had a prevalence below 1%, while older U.S. adults had a prevalence of 4%. The age-specific values use the same cited NHANES period but should still be read as subgroup estimates, not as a universal risk for every person in those age categories.
These U.S. figures are historical biomarker estimates from 2003–2006. They should not be presented as current prevalence without a newer measurement period.
Risk of multiple deficiencies
Single-nutrient statistics can understate the number of people with broader nutritional risk. A study using NHANES data found that 31% of the U.S. population aged over 9 years was at risk of at least one vitamin deficiency or anemia category. Within that total, 23% were at risk of deficiency in one vitamin or anemia category, and 6.3% were at risk in two vitamins or anemia categories.
The source abstract does not state the study period for these estimates. They therefore provide an NHANES-based picture of concurrent micronutrient risk, but not a dated current estimate. “At risk” also differs from confirmed biochemical deficiency: it describes the study’s risk classification across vitamin and anemia categories.
Source: Risk of Deficiency in Multiple Concurrent Micronutrients in Children and Adults in the United States.