Using Ozempic or Mounjaro? These key nutrients may be harder to get

People using weight-loss injections such as Ozempic and Mounjaro may be more likely to miss out on essential nutrients, according to a review of several studies.

These medicines, known as GLP-1 treatments, suppress appetite and slow the passage of food through the stomach, which can help people eat less and lose weight.

However, smaller portions can also make it more difficult to get enough vitamins and minerals.

Researchers at the Harvard T.H. Chan School of Public Health and the University of Copenhagen highlighted those concerns in an analysis of earlier studies, leading to calls for stronger nutritional guidance.

The review flagged possible shortfalls in vitamin B12, a nutrient needed for healthy nerve function. It also found that 43% of people taking GLP-1 medicines were not getting enough protein and fibre.

The researchers said: “As GLP-1 prescriptions reach millions of patients across diverse and often under-resourced clinical settings, integrating nutrition into this care model is not just advisable; it is urgent.”

Another review found that 13.6% of more than 480,000 adults using GLP-1 drugs had a vitamin D deficiency after a year of treatment.

The findings do not mean everyone taking a weight-loss injection will develop a deficiency, but experts say food quality still matters when appetite is reduced.

The British Nutrition Foundation advises people taking weight-loss medication to prioritise foods that deliver plenty of nutrients without adding many calories.

The organisation recommends choosing nutrient-rich foods that provide more vitamins, minerals and fibre per calorie, such as wholegrains, lean protein foods, fruit, vegetables and dairy or fortified alternatives.

“A small handful of unsalted nuts is a great swap for a chocolate biscuit.”

The foundation also suggests paying attention to calcium, iodine and vitamin B12.

It says dairy products such as milk, yoghurt and cheese, or fortified plant alternatives, provide calcium, iodine and vitamin B12, which are important for bone and overall health.

Other sources include canned fish with bones, such as sardines, leafy green vegetables like kale, and fortified cereals.

Experts also advise considering a daily vitamin D supplement during the darker months in the UK, when sunlight levels are lower.