Seasonal affective disorder or SAD, Sunlight and it’s affect on Vitamin D intake – The Winter Blues.
SAD is sometimes known as “winter depression” because the symptoms are more apparent and tend to be more severe during the winter.
Symptoms of SAD can include:
- a persistent low mood
- a loss of pleasure or interest in normal everyday activities
- feelings of despair, guilt and worthlessness
- feeling lethargic (lacking in energy) and sleepy during the day
- sleeping for longer than normal and finding it hard to get up in the morning
- craving carbohydrates and gaining weight
The exact cause of SAD isn’t fully understood, but it’s often linked to reduced exposure to sunlight during the shorter autumn and winter days.
The main theory is that a lack of sunlight might stop a part of the brain called the hypothalamus working properly, which may affect the:
- production of melatonin – melatonin is a hormone that makes you feel sleepy; in people with SAD, the body may produce it in higher than normal levels
- production of serotonin – serotonin is a hormone that affects your mood, appetite and sleep; a lack of sunlight may lead to lower serotonin levels, which is linked to feelings of depression
- body’s internal clock (circadian rhythm) –your body uses sunlight to time various important functions, such as when you wake up, so lower light levels during the winter may disrupt your body clock and lead to symptoms of SAD
The main treatments are:
- lifestyle measures, including getting as much natural sunlight as possible, exercising regularly and managing your stress levels
- light therapy – where a special lamp called a light box is used to simulate exposure to sunlight
SAD and the associated link with the lack of sunlight also has a knock on effect to the lack of vitamin D, so if you shun the sun, suffer from milk allergies, or adhere to a strict vegan diet you may be at risk of vitamin deficiency. Known as the sunshine vitamin, vitamin D is produced by the body in response to skin being exposed to sunlight. It is also occurs naturally in a few foods — including some fish, fish liver oils, and egg yolks — and in fortified dairy and grain products.
Vitamin D is essential for strong bones, because it helps the body use calcium from the diet. Traditionally, vitamin D deficiency has been associated with rickets, a disease in which the bone tissue doesn’t properly mineralize, leading to soft bones and skeletal deformities. But increasingly, research is revealing the importance of vitamin D in protecting against a host of health problems including cardio vascular disease, childhood asthma and cancer.
How Does Sunlight Give You Vitamin D?
Most people get some vitamin D from sunlight. When the sun shines on your bare skin, your body makes its own vitamin D but you probably need to absorb more than that. Fair-skinned people might get enough in 5-10 minutes on a sunny day, a few times a week. But cloudy days, the low light of winter, and the use of sun block (important to avoid skin cancer and skin aging) all interfere. Older people and those with darker skin tones don’t make as much from sun exposure. Experts say it’s better to rely on food and supplements to get your daily dose of Vitamin D.
Dining With Vitamin D
Many of the foods we eat have no naturally occurring vitamin D, however, fish such as salmon, swordfish, or mackerel is one big exception — and can provide a healthy amount of vitamin D in one serving. Other fatty fish such as tuna and sardines have some “D,” but in much lower amounts. Small amounts are found in egg yolk, beef liver, and fortified foods like cereal and milk.
If we can all get a daily dose of our Vitamin D in our diet throughout the Winter months it’ll see us through until we start to see the sun again in Spring, and don’t forget the benefits of a good brisk walk in the Winter sun.