As the clocks go back on Sunday 26th October 2025, the shorter days of autumn and winter mean less sunlight exposure, making it harder for people in the UK to maintain adequate vitamin D levels. With limited daylight, the body struggles to produce this essential nutrient naturally, increasing the risk of deficiency. Registered nutritionist Lily Keeling, recipe development manager at Green Chef, a recipe box delivery service, shares her advice on maintaining healthy levels through diet during the darker months.

Why vitamin D matters

Vitamin D is crucial for healthy bones, teeth, and muscles because it helps the body regulate and absorb calcium effectively. “Vitamin D is a key nutrient for maintaining healthy teeth, bones and muscles because it helps your body to regulate and absorb calcium more effectively,” says Keeling. A deficiency can lead to fatigue, muscle aches, and bone discomfort. Most people need around 10 micrograms of vitamin D daily, but the average UK diet provides less than three micrograms, and this gap widens in winter.

Rising interest in vitamin D foods

Public interest in vitamin D is growing, with around 27,000 monthly Google searches for “vitamin D foods.” While sunlight remains the primary source between April and September, Keeling notes that dietary adjustments are necessary in colder months and advises checking food packaging for nutrient information.

Foods naturally rich in vitamin D include:

• Oily fish such as mackerel and salmon
• Egg yolks
• Mushrooms
• Fortified milk alternatives like soy and almond milk

Practical ways to increase intake

Keeling highlights mushrooms as one of the simplest ways to raise vitamin D intake. “The simplest way to increase your vitamin D levels through your diet is by increasing your mushroom intake,” she explains. She recommends portobello, button, or chestnut mushrooms grown in sunlight or under UV lamps, as indicated on packaging. A portion of 80 to 100 grams, which equals one large portobello, 11 to 14 button, or four to five chestnut mushrooms, can meet daily vitamin D requirements.

Fortified milk alternatives offer another effective solution. “You can also increase your intake by carefully choosing milk alternatives that have been fortified with vitamin D and calcium,” Keeling adds. While UK cow’s milk is typically not fortified, soy or almond milk often contains added vitamin D, making them practical options for boosting levels with minimal changes to routine.

Health implications and simple choices

For those who eat oily fish, options such as mackerel and salmon remain excellent sources. However, Keeling’s tips focus on accessible, plant-based alternatives suitable for most households. Mushrooms and fortified milk alternatives are easy to incorporate into daily meals and require little effort, making them ideal for people looking to improve their nutrient intake during the winter months.

Low vitamin D levels can lead to symptoms like fatigue and muscle aches, and long-term deficiency may affect bone health. By adding vitamin D-rich foods and checking product labels, individuals can support overall wellbeing throughout the colder season.

As daylight hours decrease, Keeling’s advice provides simple ways to maintain good health through diet. Incorporating mushrooms and fortified milk alternatives into regular meals can help the public stay energised and resilient through winter. For personalised recommendations, consulting a nutritionist or reviewing nutrient labels can help ensure optimal vitamin D intake.