Winter is in full force in the Midwest right now. The fun and excitement of the holiday season is over and the days are short but the nights are long and cold. A winter storm dropped about 8 inches of snow in my town over the weekend, and another storm is on the way for this weekend. Yuck!! Does anybody have a spare bedroom somewhere warm and sunny?

Now is a great time to talk about vitamin D levels, since many of us in the cold, snowy northern hemisphere aren’t able to spend enough time in the sun to get our vitamin D levels up into ideal range. Guess what also happens when vitamin D levels drop? Seasonal Affective Disorder rates go up! Many people develop mood changes in the winter including sadness, low energy levels, sleeping more than normal, agitation and anxiety, difficulty concentrating, and even overeating carbs in a short-term attempt to increase serotonin.

There are several theories as to what causes seasonal affective disorder (SAD). Some possibilities are that low levels of sunlight cause reduced levels of serotonin and higher levels of melatonin during the day. Light therapy has been very effective in helping patients with SAD, probably by increasing serotonin and decreasing melatonin levels during the day. (Melatonin is important at night to help us sleep.). Lower activity levels in the winter might also increase depressive symptoms. Exercise has been shown to be very effective in improving depression.

But back to vitamin D. Studies have shown that people with low levels of vitamin D have an increased risk of depression. A study from Sweden showed that people who had attempted suicide had lower vitamin D levels than non-suicidal people. They also had higher levels of inflammatory chemicals, called cytokines. Vitamin D can reduce these inflammatory chemicals.

So how do we know if we have enough vitamin D? Vitamin D levels are considered normal between 30 to 100 ng/ml. I personally think that the normal range should start at 50ng/ml, based on research that showed that nursing moms needed levels above 50 to get vitamin D into breast milk (so levels below 50 will result in vitamin D deficiency in their babies). Some experts recommend levels around 80 ng/ml for fighting or preventing cancer. Of course, many health insurance companies may not cover testing vitamin D levels but there are less expensive options that can be done from your own home. You can order a finger stick vitamin D test from the Vitamin D Counsel for only $58 (link is posted below).

So how much vitamin D does someone need to correct a deficiency? A lot more than the Recommended Daily Allowance of 400-800 iu/day! When I still did OB, many of my patients were taking 10,000 iu/day and still their levels were below 50. The over the counter vitamin D is actually better than the prescription one, and it’s way cheaper, too. If you do choose to use high dose vitamin D, you should check a level to make sure you aren’t getting too much.

The Vitamin D Counsel also has an extensive collection of articles on all aspects of the health benefits of Vitamin D. Please consider becoming a member or otherwise support this fantastic organization. Vitamin D is involved in thousands of chemical reactions in the human body. I believe that normalizing vitamin D levels can not only help improve Seasonal Affective Disorder, but all sorts of other chronic health issues.

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Dr. Bonnett has over 20 years of experience in general medicine, mostly working with female patients. For over a decade, she has researched and used natural hormone replacement to help women optimize function and well-being. She can help bridge the gap between cutting-edge science and applying that science to help real people regain health.

Dr. Valerie Bonnett | Restorative Health & Wellness for Women


"Many women suffer from loss or imbalance of natural hormones. Hormone loss or imbalance can cause major symptoms such as hot flashes, night sweats, insomnia, mood symptoms, and even memory issues. Hormone loss and imbalance is also associated with major medical problems such as heart disease, high blood pressure, and even increased cancer risk. Some women lose most of their hormones around the time of menopause, but many women have hormonal imbalance much earlier....even going back to their teens. Hormonal imbalance can cause emotional imbalance. Many women get placed on meds for depression and anxiety....when they would do better getting their hormones back to normal!" ~ Dr. Valerie Bonnett

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