New survey finds lower levels of vitamins and iodine in UK milk
11 Apr 2025
A new survey of cows’ milk on sale in UK supermarkets has found that it contains lower levels of vitamin B12, riboflavin and iodine compared to nearly 30 years ago.
In 1996 a 200ml glass of milk provided about half of the 1.5 µg required vitamin B12 intake for adults – known as the Reference Nutrient Intake.
However, updated values used in the government’s latest National Diet and Nutrition Survey suggest this amount of milk now supplies only around a quarter of that daily requirement.
The survey was run by the Quadram Institute’s Food and Nutrition National Bioscience Research Infrastructure (FN-NBRI) and funded by the Department of Health and Social Care and the Biotechnology and Biological Sciences Research Council, part of UK Research & Innovation (UKRI).
Samples from the most popular brands of cows’ milk from 10 different supermarket chains were combined and analysed to provide representative average nutrient levels for skimmed, semi-skimmed and whole fat milk, both pasteurised and UHT.
The research was carried out in 2022 and 2023, in summer and winter to examine seasonal differences in the amount of nutrients.
Dairy products are the largest contributors to the UK population’s intake of vitamin B12, riboflavin (vitamin B2) and iodine, according to the National Diet and Nutrition Survey.
The Quadram study suggested that levels in milk of vitamin B12 – which helps make blood cells, DNA and maintains the health of nerve cells – were 50% lower on average compared to 1996.
For both summer and winter seasons, the 2023 analysis demonstrated that all pasteurised milk samples were between 0.3 to 0.5μg per 100g – markedly lower than the 0.7 to 0.9μg per 100g recorded in 1996.
Also, UHT milk samples showed lower average levels of vitamin B12 compared to pasteurised milk in both the 1996 and 2023 analyses.
However, researchers cautioned that change in values did not necessarily reflect a decrease in the actual vitamin B12 content but might be due to adjustments in the analytical methods used.
Additionally, less than 10% of the adult population qualifies as vitamin B12 deficient, based on serum vitamin B12 levels reported by the survey.
Pic: Cottonbro
