Vitamin D deficiency affects millions in the US and UK

Health experts are highlighting the prevalence and symptoms of vitamin D deficiency in the United States and the United Kingdom. In the US, an estimated 35 percent of adults suffer from a deficiency, which can lead to muscle weakness, cramps, fatigue, and low mood. Severe or long-term deficiency may cause osteomalacia, a condition where bones become soft and weak, and can increase the risk of osteoporosis.

In the UK, approximately one in six people have sub-optimal vitamin D levels. Experts note that during autumn and winter, insufficient UVB exposure makes it difficult to synthesize the vitamin through the skin. Clinical nutritionists suggest that everyone in the UK should consider a daily 10 microgram supplement during these months.

Beyond bone and muscle health, vitamin D plays a role in immune system support and mood regulation. Insufficient levels may contribute to seasonal affective disorder (SAD), a form of depression linked to reduced light exposure. Certain groups, including women, people with darker skin tones, and those with limited sunlight exposure, may benefit from year-round supplementation.