Millions in UK ‘missing out’ on ‘crucial’ vitamin that boosts immune system

Britons may be consuming sufficient calories yet still falling short on essential nutrients required for both immediate and long-term health and wellbeing, according to a new report, Dietary Deficits and Future Health and Wellness Fallouts, from the Health and Food Supplements Information Service (HSIS). Experts have warned that millions could be experiencing “hidden hunger” — a term describing nutrient deficiencies that can silently impact health even when individuals appear to be eating adequately.

Public health nutritionist Dr Emma Derbyshire, from the Health and Food Supplements Information Service, said: “The report just published found that 93% of adults believe their diet could be healthier, while more than six in ten say the cost-of-living crisis has affected their food choices. And while 60% of adults claim they try to hit their five-a-day target of fruit and veg, official government dietary surveys suggest fewer than one in five actually achieve it.”

Health professionals warn the implications will be wide-reaching, with nutritional deficiencies affecting immune function, energy levels, bone density, cardiovascular and brain health, and even mental performance. Specialists suggest that escalating food prices are steering many households away from nutrient-dense options towards cheaper, more satisfying alternatives.

Dr Derbyshire said: “The HSIS report highlights significant shortfalls across several essential nutrients – including vitamin D, folate, calcium, iron, iodine, selenium, potassium and omega-3 fatty acids. Importantly, these nutrients do not work in isolation. Shortfalls can interact and compound one another.

“For example, vitamin D is needed for calcium absorption, magnesium helps activate vitamin D, while vitamin C improves iron uptake. This means one deficiency may trigger a wider nutritional domino effect across the body.”

Doctor’s top nutrients Britons may be falling short on

Dr Derbyshire said: “Vitamin D remains one of the UK’s biggest nutritional concerns, particularly during autumn and winter when sunlight exposure drops. It plays a crucial role in immune defence, muscle function and bone health.”

Specialists recommend combining sensible sun exposure with foods such as eggs, mushrooms and oily fish, while noting that many adults could benefit from a daily multivitamin and multimineral supplement containing vitamin D, or a dedicated vitamin D supplement.

Dr Derbyshire continued: “Iron is another major concern, particularly among women and teenagers. Around 34% of women aged 19–64 have iron intakes below recommended levels. Low iron levels can contribute to tiredness, poor concentration and low mood. Pairing plant-based iron sources such as lentils or spinach with vitamin C-rich foods like kiwi, peppers, or strawberries may help improve absorption.

“Omega-3 fatty acids linked to heart and brain health are lacking in many people’s diets. Sardines and mackerel are among the richest sources, while walnuts and chia seeds can help boost plant omega-3 intakes. If you don’t like oily fish, then bridge those dietary gaps with an omega-3 or fish oil supplement.

“Consumers are right to be worried about their diets as the government’s own diet research highlights that our nutrient intakes haven’t improved for years and – in many cases – continue to get worse. Any single nutrient gap is of concern, but the pattern of shortfalls we’ve seen is particularly worrying for future health.

“To help bridge nutritional gaps, a multivitamin and multimineral supplement provides a useful self-care nutritional safety net alongside a balanced diet.

“Targeted supplements such as vitamin D, omega-3 fish oils and iron may also benefit some groups, particularly during periods of low sun exposure or increased nutritional need.”