So, what can you do now to support your mood through the darker months? We asked three experts – a psychiatrist, a GP and a nutritionist – to share their best advice.
What causes SAD?
Scientist don’t yet know the exact cause, but current research highlights a strong link to a lack of sunlight. After all, light is our body’s strongest circadian cue, influencing sleep-wake cycles and hormone production. Less light exposure means more melatonin (the sleep hormone) and less serotonin (the ‘happy hormone’). “Sunlight exposure directly impacts serotonin levels,” adds Rotaru. “Studies show we tend to have higher serotonin on bright, sunny days, regardless of temperature.”
There are also behavioural factors at play. “In colder, darker months, people tend to go out less, exercise less and socialise less. That withdrawal can create a cycle that deepens low mood,” Rotaru adds.
7 tips to support your mood this winter
1. Hack your serotonin with food
While nutrition can’t cure SAD, it can help stabilise mood and energy. Registered nutritionist Zara Hiridjee says it all starts with serotonin production.
“Serotonin is synthesised from the amino acid tryptophan, found in foods like eggs, turkey, salmon, tofu and nuts,” she explains. “But tryptophan has to cross the blood-brain barrier, where it competes with other amino acids. If you eat protein alone, the competition is high, and relatively little tryptophan gets through. Pairing it with complex carbohydrates – say, scrambled eggs on wholegrain toast, or salmon and quinoa salad – it changes the balance of circulating amino acids, allowing more tryptophan to enter the brain.”
2. Feed your gut and balance your blood sugar
About 90% of serotonin is produced in the gut, so a diverse diet matters. “Aim for 20-30 different plant foods per week to encourage the gut bacteria to produce short-chain fatty acids and neurotransmitter precursors that can positively influence mood,” says Hiridjee. “That includes beans, lentils, nuts, seeds, vegetables and wholegrains. Adding fermented foods like kefir or sauerkraut also supports healthy bacteria.”
Blood sugar stability is equally important. “If you start the day with something high in refined carbohydrates, say a croissant or white toast, you’ll get a rapid glucose spike, followed by a sharp dip,” Hiridjee warns. “That dip can trigger fatigue, irritability, cravings and even anxiety-like symptoms. To avoid that rollercoaster, meals should combine complex carbohydrates, protein and healthy fats like oats with Greek yoghurt, berries and nuts; or a wholegrain wrap with hummus, vegetables and chicken. Fibre is critical too, it slows digestion, feeds the microbiome and supports more stable energy release.”
3. Prioritise vitamin D and other key nutrients
From October to March in the UK, the body can’t make vitamin D from sunlight. “Low vitamin D is linked to fatigue and low mood,” says Hiridjee. “I recommend most people start with a safe daily dose of 10micrograms (400 IU), though some people may benefit from more depending on their individual needs.”
Omega-3 fatty acids from oily fish like salmon or sardines also supports brain cell function, while B vitamins (particularly B6, folate and B12) are crucial for neurotransmitter pathways. Magnesium, zinc and iron contribute to resilience against fatigue and low mood, too.
4. Step outside for light and movement
Light is the most powerful external cue for our circadian rhythm, our body’s internal clock. With changes in light exposure, this impacts our body’s melatonin production, meaning that our sleep/wake cycle is disrupted.
“This can affect your mood due to changes in our energy levels and ability to concentrate,” explains Rotaru. “Sunlight exposure on the skin produces that Vitamin D, that plays an active role in brain health and serotonin activity.”
Outdoor light is many times stronger than indoor lighting, even on a grey day. “Even aiming for 30 minutes of daily exercise, five days a week can help to uplift mood,” says Dr Semiya Aziz, GP and founder of Say-GP. “Outdoor activities provide the double benefit of encompassing both movement and exposure to light, which in turn can limit SAD symptoms.”
It doesn’t have to be vigorous: even daily short walks, stretches or gentle activity can help to lift energy.
5. Brighten mornings with light therapy
Light therapy is one of the most evidence-based interventions for SAD. Special lamps, delivering at least 10,000 lux, mimic daylight and can reduce symptoms when used for 20-30 minutes each morning.
“Start using a SAD lamp in early autumn, before symptoms peak,” advises Dr Aziz. “Make sure you choose a lamp specifically designed for SAD with the standard kite mark and not just any old lamp. Always check with your GP first about SAD lamps, especially if you suffer with eye problems, medical conditions or take certain medications.”
Some people also find dawn-simulating alarm clocks, which gradually increase light in the bedroom, useful for regulating sleep.
6. Reset your body clock with routine
Sleep disruption is a common feature of SAD. “Routine is key,” says Dr Aziz, who recommends:
• Going to bed and waking up at the same time daily.
• Avoiding screens for at least an hour before bed.
• Keeping the bedroom cool, dark and quiet.
• Limit caffeine intake after 12pm and avoid alcohol near bedtime.
• Create a calming routine like reading, stretching, warm shower or listening to a podcast.
Lifestyle changes can make a big difference, but sometimes professional help is necessary. Aziz stresses: “See your GP if symptoms are severe, if they interfere with your daily life, or if you feel hopeless or have thoughts of self-harm. It’s also important to rule out other causes such as thyroid issues or vitamin D deficiency.”
Treatment options include light therapy, medication and talking therapies such as Cognitive Behavioural Therapy (CBT). “BT therapists support their client to re-engage with activities that are meaningful and have a positive impact, create and maintain a routine as well as challenge any negative thinking,” Rotaru adds.
Small changes now can build resilience for months ahead. As Hiridjee puts it: “There’s no single superfood or shortcut. It’s about consistent patterns – Mediterranean-style eating, daily daylight, steady routines. Together, these create a buffer against the winter slump and help protect your mood.”
Further reading…
How to beat the winter blues
Healthy, mood-boosting recipes
Best Vitamin D supplements, tried and tested
