By Dr. Mercola
It’s been estimated1 that as many as 20 percent of Americans are affected by Seasonal Affective Disorder (SAD) each winter, suffering from the blues, fatigue, and in some cases, more serious depression as sunlight grows scarce.
What differentiates SAD from regular depression is that a full remission occurs in the spring and summer months.
Scientists generally recommend full-spectrum light therapy over SSRIs like Prozac or Zoloft for this condition, as it has virtually no side effects and is much cheaper than prescription drugs, and I wholeheartedly agree with this recommendation.
The fact that SAD and the winter blues occur when the days begin to darken and sunlight is at a minimum is not a coincidence. Your health and mood is intricately tied to exposure to sunlight. For example, your serotonin levels (the hormone typically associated with elevating your mood) rise when you're exposed to bright light.
Your melatonin level also rises and falls (inversely) with light and darkness. When it's dark, your melatonin levels increase, which is why you may feel tired when the sun starts to set (and in the heart of winter, this may be at as early as 4:00 p.m.).
Light and darkness also control your biological clock, or circadian rhythm, which impacts hormones that regulate your appetite and metabolism.
As noted by Medicine Net,2 “Keeping your home and workplace as sunny and bright as you can help. It also helps to spend more time outdoors and to get regular exercise.”
Maintaining Mental Wellness During Winter Months
Vitamin D deficiency has long been associated with Seasonal Affective Disorder3 (SAD), as well as more chronic depression.4 For example, one double-blind randomized trial5 published in 2008 concluded that:
“It appears to be a relation between serum levels of 25(OH)D and symptoms of depression. Supplementation with high doses of vitamin D seems to ameliorate these symptoms indicating a possible causal relationship.”
Light can be shed on this connection when you consider that vitamin D receptors appear in a wide variety of brain tissue, and activated vitamin D receptors increase nerve growth in your brain. It’s therefore important for all-around brain function and mental health.
Sara Hayden, a mental health therapist at TFP Therapeutic Services in Ontario, Canada, recommends the following vitamin D-boosting strategies to address the wintertime blues:6
- Vitamin D3 supplements (avoid vitamin D2, which is what most doctors still prescribe, as it might do more harm than good in the long term)
- Full-spectrum light bulbs and/or light box
- Get outdoors as much as possible whenever the sun is out
To this, I would add using a tanning bed with an electronic ballast (to avoid the potentially harmful EMF fields generated by magnetic ballast systems. If you hear a loud buzzing noise while in a tanning bed, it has a magnetic ballast system.)
I believe this may be a more ideal way to optimize your vitamin D, allowing you to minimize the amount of oral vitamin D you need to take. If you do opt for a supplement, remember to take vitamin K2 and magnesium in conjunction with it.
Since vitamin D is fat soluble, taking some form of healthy fat with it will also help optimize absorption. Vitamin A, zinc, and boron are other important cofactors that interact with vitamin D.
Vitamin D Deficiency Is Extremely Common
Vitamin D deficiency is very common, and should be a top consideration when you’re looking for a solution to flagging mood and energy—especially if it occurs during fall and winter months.
British National Diet and Nutrition surveys from 2008/2009 to 2011/2012 indicate that 25 percent of British adults have low vitamin D status.7
In the US, the statistics paint an even bleaker picture. The National Health and Nutrition Examination Survey found that 50 percent of children aged one to five years and 70 percent of children between the ages of six and 11, are deficient or insufficient in vitamin D.
Ninety-five percent of US senior citizens are also thought to be deficient, not only because they tend to spend a lot of time indoors but also because they produce less vitamin D in response to sun exposure (a person over the age of 70 produces about 30 percent less vitamin D than a younger person with the same sun exposure).8
One of the leading vitamin D researchers, Dr. Michael Holick, estimates that 50 percent of the general population is at risk of vitamin D deficiency and insufficiency.
A recent report9 issued by the British National Institute for Health and Care Excellence (NICE) suggests children should be given free vitamin D supplements to address “a hidden epidemic of deficiency” that is driving disease statistics.
NICE also urges supermarkets to stock low-cost vitamin D supplements, and to promote them to high-risk groups, such as pregnant women, seniors, and people with darker complexion.
The Importance of Vitamin D Testing
Ideally, you’ll want to get your vitamin D level tested before you start taking supplemental vitamin D. This will help you fine-tune your dosage over time. This time of year, after several months of minimal sun exposure, is an ideal time to test your vitamin D levels to get an idea of what your levels are at their lowest.
GrassrootsHealth has a helpful chart showing the average adult dose required to reach healthy vitamin D levels based upon your measured starting point. The clinically relevant level you’re looking for is between 50-70 ng/ml, and for optimal all-around health, you’ll want to maintain this level year-round.
In the summer, this is best done by getting plenty of sensible sun exposure. This is my personal strategy, and despite not taking a vitamin D supplement for over five years, I’ve been able to maintain a level in the 70 ng/ml range.
Blue Light Has Beneficial Effect on Mood
Previous research has shown that while daylight as a whole is beneficial to fight off the winter blues, different colors of light can affect your body in different ways. Blue light has been found to be particularly beneficial for boosting your mood—more so than red or green light. According to one 2010 study,10 blue light appears to play a key role in your brain's ability to process emotions, and its results suggest that spending more time in blue-enriched light could help prevent SAD.
It may be even more effective than the bright white light currently used in light boxes to treat SAD and other forms of depression. Blue light is prevalent in outdoor light, so your body absorbs the most during the summer and much less in the winter. Because of this, the researchers suggested that adding blue light to indoor lighting, as opposed to the standard yellow lights typically used, may help boost mood and productivity year-round, and especially during the winter. Keep in mind, however, that blue light at night should be avoided and there are yellow glasses that help filter out the blue wavelengths that if viewed before bedtime can impair your sleep.
As I’ve discussed before, one of the reasons for insomnia and poor sleep is due to excessive exposure to blue light-emitting technologies such as TV and computer screens. The blue light depresses melatonin production, thereby preventing you from feeling sleepy. In a previous interview, researcher Dan Pardi explains the peculiar effect blue light has on your brain, which sheds further light on why it’s so important to expose yourself to blue light during daytime hours, and why you need to avoid it at night:
"[R]ods and cones in the eye... are specialized cells that can transduce a photo signal into a nerve signal... In the mid-90s, a different type of cell was discovered... [called] intrinsically photosensitive Retinal Ganglion Cells (ipRGC). It does the same thing as rods and cones: it transduced light to a nerve signal. But instead of the signal going to your visual cortex, it goes to your master clock. Those cells are most responsive to blue light.
If you can block blue light, you can actually create something called circadian darkness or virtual darkness. What that means is that you can see, but your brain doesn't think that it's daytime; your brain thinks that it's in darkness. That is actually a practical solution for living with artificial light in our modern world... With more awareness, future digital devices will adjust lighting in the evening to automatically dim and emit amber/red light [instead of blue]. This is much better for healthy circadian rhythms and sleep quality."
Additional Tips for Beating the Winter Blues
Light is a major factor in overcoming SAD, but you can also help boost your mood naturally during the dark, cold winter by:
- Exercising: Regular physical activity has been found to work better than antidepressant drugs. In fact, it’s one of the most powerful strategies available to prevent and treat depression and boost your mood.
- Going to sleep early, and/or addressing insomnia. You were designed to go to sleep when the sun sets and wake up when the sun rises. If you stray too far from this biological pattern you will disrupt delicate hormonal cycles in your body, which can affect both your mood and your health. The link between depression and lack of sleep is well established. Of the approximately 18 million Americans with depression, more than half of them struggle with insomnia. In one study, 87 percent of depression patients who resolved their insomnia had major improvements to their depression, with symptoms disappearing after eight weeks.
While there are individual differences, as a general rule, you’ll want to aim for about eight hours of sleep per night. If you don't already have a fitness tracker that records your sleep, I would encourage you to get one. It’s difficult to change a habit when you’re not monitoring it, and chances are you’re not getting nearly as much sleep as you think you do. Using a sleep tracker can help motivate you to get to bed earlier so you can get eight hours of sleep. Jawbone’s Up311 is among the most advanced fitness tracker to date and should be out in early 2015, but there’s an explosion of fitness trackers coming, so even more advanced ones are sure to follow. The Apple Watch,12 which is set to launch this year is one example. I have reviewed many of them and Jawbone is one of the best.
- Avoiding processed foods. A factor that cannot be overlooked is your diet. Foods have an immense impact on your mood and ability to cope, and eating a diet of fresh, whole foods as described in my nutrition plan will best support your mental health. Refined sugar and processed fructose are known to have a very detrimental impact on your brain function and mental health in general. There's a great book on this subject, The Sugar Blues written by William Dufty more than 30 years ago, which delves into this topic in great detail. Cutting out artificial sweeteners will also eliminate your chances of suffering their toxic effects.
- Optimizing your gut health.Fermented foods such as fermented vegetables are also important for optimal mental health, as they are key for optimizing your gut health. Many fail to realize that your gut is literally your second brain, and can significantly influence your mind, mood, and behavior. Your gut actually produces more mood-regulating serotonin than your brain does.
- Increasing high-quality, animal-based omega-3 fats. Your brain consists of about 60 percent fat, DHA specifically, so you need a constant input of essential omega-3 fats for your brain to work properly. In fact, one 2009 study13 showed that people with lower blood levels of omega-3s were more likely to have symptoms of depression and a more negative outlook while those with higher blood levels demonstrated the opposite emotional states.