A KEY vitamin is linked to both reduced bowel cancer risk and improved outcomes for those who already have it, say researchers. While it's available in supplement form, Brits can enjoy it for free over the coming months. Vitamin D plays a crucial role in maintaining overall health, particularly bone health, by aiding in the absorption of calcium and phosphorus, which are essential for bone formation and maintenance. It also supports immune function, muscle function, and potentially influences other aspects of health, including mood and cardiovascular health. Now, a new study published in the journal Nutrients has linked vitamin D levels with lower risk of bowel cancer - which has been on the rise in younger adults. Reviewing data from 50 different studies on vitamin D and bowel cancer, researchers found those with the highest dietary intake of vitamin D (80 ng/ml) had a 25 per cent decrease in bowel cancer, compared to those with the lowest amount (10 ng/ml). Data from the Nurses' Health Study - a US study that investigated the risk factors for the top chronic diseases in women - revealed women with the highest vitamin D intake had a 58 per cent lower risk of bowel cancer, compared to those with the lowest intake. The study authors wrote: "Maintaining optimal vitamin D levels and adequate dietary intake is crucial in preventing bowel cancer and improving patient prognosis." Vitamin D may provide anti-cancer benefits by combating the inflammation that can trigger changes that become cancer. It may also help kill cancer cells and inhibit tumour growth by boosting the body's immune system, the researchers said. In the study, the Hungarian experts also highlighted how vulnerable many people are of having vitamin D deficiency. They wrote: "Urban populations, where air pollution and sense infrastructure limit sunlight exposure, are at greater risk." They added this risk is especially high among European populations. "Approximately 40 per cent of Europeans are considered vitamin D deficient, with 13 per cent classified as severely deficient," they wrote. During winter (January to March), it's estimated that approximately 40 per cent of people aged 19-64 and 29.3 per cent of people aged 65 and over in the UK have low vitamin D levels, according to National Institute for Health and Care Excellence (NICE). The body creates vitamin D when exposed to sunlight. But during the autumn and winter months in the UK, because the sun isn't strong enough for the body to make vitamin D, Brits are advised to take a vitamin D supplement - pregnant and breastfeeding women especially. What to remember when taking vitamin D supplements Between late March/early April to the end of September, most people can make all the vitamin D they need through sunlight on their skin and from a balanced diet. The Department of Health and Social Care recommends adults and children over four take a daily supplement containing 10 micrograms of vitamin D throughout the year if they: are not often outdoors – for example, if they're frail or houseboundare in an institution like a care homeusually wear clothes that cover up most of their skin when outdoors People with dark skin – for example people who have an African, African-Caribbean or south Asian background – may also not make enough vitamin D from sunlight, so should consider taking a daily supplement containing 10 micrograms of vitamin D throughout the year. The Department of Health and Social Care also recommends babies from birth to one year of age should have a daily supplement containing 8.5 to 10 micrograms of vitamin D throughout the year if they are: breastfedformula-fed and are having less than 500ml (about a pint) of infant formula a day, as infant formula is already fortified with vitamin D Children aged one to four years old should be given a daily supplement containing 10 micrograms of vitamin D throughout the year. You can buy vitamin D supplements or vitamin drops containing vitamin D (for under fives) at most pharmacies and supermarkets for as little as 2p a pill - Nutrition Geeks's Vitamin D3 4000iu + K2, for example, is £9.99 for 365 tablets. Taking too many vitamin D supplements over a long period of time can cause too much calcium to build up in the body (hypercalcaemia). This can weaken the bones and damage the kidneys and the heart. For people who choose to take vitamin D supplements, 10 micrograms a day is enough. Don't take more than 100 micrograms (4,000 IU) of vitamin D a day as it could be harmful, warns the NHS. This applies to adults, including pregnant and breastfeeding women and the elderly, and children aged 11 to 17 years. Children aged one to 10 years should not have more than 50 micrograms (2,000 IU) a day. Infants under 12 months should not have more than 25 micrograms (1,000 IU) a day.