Picture used for illustrative purposes.

Daily multivitamin pill intake may not actually lower risk of death and help healthy adults live longer, a new study suggests.

Researchers from the US National Cancer Institute assessed data from nearly 400,000 healthy adults followed for more than 20 years.

The study found no association between a regular multivitamin use and lower risk of death.

Many adults regularly take multivitamins hoping the habit would improve their health, however, the exact benefits and harms of taking them daily remain unclear, the study, published in the journal Jama Network Open, said.

Some reports suggested a third of all US adults take multivitamins hoping it would prevent any potential disease in the future.

Existing research probing the link between their intake and mortality are limited by short follow-up times.

To overcome this, the new study analysed data from three large, geographically diverse studies involving over 390,000 US adults who were followed for over two decades.

The study participants were generally healthy, with no history of cancer or other chronic diseases, researchers said.

With such a large data sample, the new research could mitigate the effects of likely biases that may have influenced previous studies.

For instance, in the previous studies, sicker participants may have already been more likely to increase their use of multivitamins.

And people with healthier lifestyles in general may have been assessed in earlier research as multivitamin takers.

The new long-term analysis showed that people who took daily multivitamins did not have a clearly lowered risk of death from any cause compared to those who did not take the pills.

Researchers did not find any differences in mortality from cancer, heart disease, or cerebrovascular diseases among those who took multivitamins every day.

The analysis also accounted for other factors such as race and ethnicity, education, and diet quality.

“In this cohort study of 390 124 US adults without a history of major chronic diseases, we did not find evidence to support improved longevity among healthy adults who regularly take multivitamins,” researchers wrote.

“However, we cannot preclude the possibility that daily MV use may be associated with other health outcomes related to aging,” they added.

On the other hand, children’s multivitamins on sale in Tesco, Boots and other major stores are “misleading” parents, experts have warned, after research found the vast majority fail to provide enough vitamin D.

Oxford and Southampton university experts studied more than 67 children’s multivitamin products on the high street and found vitamin D doses varied but only around a third met recommended daily levels.

Vitamin D is an essential nutrient which the body gets from sunlight and diet, and deficiencies in childhood can lead to rickets, a condition that causes bone malformations, weakness and stunted growth.

Producing the vitamin from sunlight is also harder in the winter months and for people with darker skin, and Public Health England recommends children aged one to four take a daily 10-microgram (400IU) supplement.

Many parents may expect that by opting for a multivitamin they’ll be able to meet all their children’s needs, but the latest study shows that belief could be misplaced.

The researchers selected children’s multivitamin products on sale at Asda, Boots, Holland and Barrett, Lloyds Pharmacy, Morrisons, Ocado, Sainsbury’s, Tesco, and Superdrug.

For children under six months of age, only one multivitamin contained more than 340IU/day vitamin D. Only a third of products for children older than six months provided the recommended 400IU per day of vitamin D, the experts said.

They also compared 24 vitamin D products that specifically said they were for healthy bones, but even some of these contained as little as 50IU of vitamin D.

It comes after analysis of NHS data showed hospital admissions related to vitamin D deficiency rose by 34 per cent last year, with more than 100,000 cases across England.

“There is a wide range of both multivitamins and vitamin D supplements available for children in the UK, yet most of these do not provide the recommended 400IU/day,” the authors wrote in the journal Archives of Disease in Childhood.

The researchers also looked at specific vitamin D supplements marketed as being for healthy bones.

While they had more vitamin D than the multivitamins, the researchers found only around two-thirds of products provided the full 400IU recommended intake and some had as little as 50IU of Vitamin D.

It comes after analysis of NHS figures showed that there were more than 100,000 hospital admissions in England for vitamin D deficiency last year – a rise of 34 per cent.

A healthy UK diet still provides less than 10 per cent of necessary vitamin D, and as young people spend more time indoors supplementation becomes more important than ever, Dr Benjamin Jacobs, of the Royal College of Paediatrics and Child Health, said.

Dr Jacobs said it was “highly concerning” that so many supplements fall short of recommended levels.

“These products are misleading parents who think they are protecting their children from serious conditions such as rickets, poor growth and muscle weakness,” he added.

However, health supplement groups said their products are not intended to provide 100 per cent of a child’s nutrients, and lower concentration products allowed young children to be given a smaller dose.

“Food supplements are meant to supplement the diet, not replace the nutrients obtained from foods,” Dr Carrie Ruxton, from HSIS, the industry-funded health and food supplements information service, said.

“Many of the supplements in this survey would actually bridge the dietary gap topping up intake towards the recommended 10 micrograms daily,” she added.

The Independent