Feeling S.A.D? Can nutrition help seasonal affective disorder?

As the nights draw in and the temperature starts to drop, many of us will occasionally feel a bit sluggish and experience the “winter blues”. However, for some people, the onset of autumn and winter can bring significant changes to mood and behaviour. For those who experience season affective disorder (S.A.D.), the changing seasons can dramatically affect mood and for many, it can be debilitating enough to have an impact on daily life.

What is S.A.D.? 

S.A.D., sometimes known as “winter depression” is a subset of depression that occurs annually, every autumn and winter when the days get shorter and darker, with full remission in spring/summer. Less commonly, some people find they experience S.A.D. in reverse – with depressive symptoms occurring in summer.

Common signs and symptoms of S.A.D. can include:

Persistent sad, anxious or “empty” mood
Loss of interest or pleasure in hobbies and activities  
Lack of energy
Poor concentration and memory
Social withdrawal (hibernation)
Changes to appetite, usually overeating
Sleep problems, often oversleeping
Physical aches and pains with no clear physical cause
Lowered immune function

What causes S.A.D.?  

The exact causes are not known, but the condition is thought to be related to a reduction in daylight exposure. One theory suggests that shorter daylight hours in winter may trigger depression in vulnerable individuals due to prolonged secretion of the sleep hormone melatonin, which is ordinarily inhibited by sunlight. Elevated levels of melatonin throughout the day can cause disturbance to our sleep-wake cycle (or circadian rhythm) and contribute to many of the symptoms of S.A.D. Another theory is that light exposure can affect mood directly, with certain cells in the retina sensitive to light, particularly blue light, influencing mood-regulating brain areas.

Other factors may include genetic predisposition and a family history of mood disorder, psychological stress, and low levels of the feel-good neurotransmitter, serotonin. S.A.D. is more common in regions situated further from the equator, characterised by more significant variations in daylight hours across different seasons. In the UK, about 3 people in every 100 have significant winter depression.

Women are more likely to experience SAD than men, with onset typically occurring in early adulthood, suggesting an association with times of peak hormone production.

Vitamin D deficiency may exacerbate the symptoms of winter-pattern S.A.D. because vitamin D has been shown to promote serotonin activity. The body produces vitamin D when exposed to ultraviolet (UV) sunlight on the skin. With less daylight in the winter, and reduced UV levels, people with SAD may have lower vitamin D levels, further reducing serotonin activity.

What is the conventional treatment for SAD?

The National Institute of Health and Care Excellence (NICO) recommends that S.A.D. should be treated in the same way as other types of depression, such as talking therapies and anti-depressant medication. Using a light box (a specialist device containing very bright fluorescent tubes) has been found to be an effective treatment for S.A.D. because it increases exposure to light during the winter months.

Nutrition and lifestyle support for S.A.D.

Increase sunlight exposure – spending as much time as you can outdoors in autumn and winter can increase your exposure to sunlight, which is associated with increased serotonin levels and improved mood.

Exercise - regular physical activity has been shown to alleviate symptoms of depression and boost serotonin levels, which may help counteract the symptoms of S.A.D. Even better if you exercise outdoors!

Stress management – the practice of mindfulness-based stress reduction techniques or relaxation exercises, such as yoga and meditation, can help to manage stress levels and improve coping skills.

Balance your blood sugar – although those with S.A.D. often crave carbohydrates, this could be compounding the problem. Eating foods that are high in sugar and simple, refined carbohydrates leads to rapid fluctuations in blood sugar levels, which can have a significant impact on the brain and its neurotransmitters. Typical symptoms of imbalanced blood sugar levels are low mood, anxiety, brain fog and fatigue. 

Avoiding these foods, and ensuring plenty of fibre, healthy fats and protein-rich foods with every meal and snack will help to balance blood sugar levels.

Boost serotonin – increasing foods rich in the amino acid tryptophan, such as eggs, cheese, poultry, nuts, seeds and tofu can help to support production of serotonin. 5-HTP (5-Hydroxytryptophan) is a natural precursor to serotonin, which is formed in the body from tryptophan and is also available in supplement form.

B vitamins -

These nutrients collectively play crucial roles in neurological function and mood regulation. Deficiencies in these vitamins have been linked to an increased incidence of depression.

Vitamin C - 

This essential antioxidant is also implicated mood regulation. Research suggests that vitamin C deficiency may lead to heightened depressive symptoms and that supplementation can help to alleviate these symptoms.

Vitamin D - 

Insufficient sunlight exposure during autumn and winter, and subsequent low levels of vitamin D may contribute to the onset of S.A.D. Individuals with vitamin D deficiency are reportedly 3.5 times more prone to developing depression.

Omega-3 -

Supplementing with the essential fatty acids EPA and DHA, often inadequate in the Western diet, has shown benefits to healthy mood balance.

Magnesium -

Another nutrient that is often deficient in the typical Western diet, this powerful mineral is used in both mood balance and energy production.