Seasonal transitions

Symptoms of Seasonal Affective Disorder are significant distress, depression, moodiness, and loss of energy. Photo by Asdrubal luna

The human body undergoes changes seasonally that scientists are only recently able to observe. The human brain and our genes respond to fall and winter differently than they do to spring and summer. Scientists have discovered that a quarter of our genes turn on or off depending on the season. During the winter, all of your genes that involve immunity fire up to fight off infections like the flu. These same genes are turned off by the body in the summer when catching an infection is less likely. Scientists believe these genes are turned off by the body because having your immune system working at a higher rate requires more energy.


During fall and winter, we have fewer daylight hours, and we are less active during the colder months. Getting less sunlight can affect our vitamin D levels. Vitamin D (often called the sunshine vitamin) levels can affect our overall health. Symptoms of low vitamin D levels are getting sick often, fatigue, chronic bone pain, depression, gut issues, wounds that won’t heal, and brittle bones. Vitamin D is essential in the body and helps improve calcium absorption. When you are low on vitamin D, your body takes it from your main vitamin D calcium supply, your bones. I recommend taking a good vitamin D supplement during the winter months.


It is important to understand that vitamin D is a fat-soluble vitamin that should be taken with vitamin K. Vitamin D ensures the calcium levels in your blood are high enough to meet your needs. Vitamin K regulates a protein called osteocalcin, which provides for the accumulation of calcium in your bones and teeth. Without osteocalcin, the calcium in your body would not make it into your bones. Instead, it would remain in your blood vessels and soft tissues and result in calcification of soft tissues and blood vessel calcification. This can lead to heart disease and kidney disease.

Osteocalcin also stimulates adiponectin which is a strong metabolism stimulator that helps maintain normal weight in humans. It is believed that low vitamin K levels in the population are a contributing factor to the obesity epidemic.

Taking both vitamin D3 and K2 supplements therefore improves overall health and long-term wellness.


During the fall and winter our eating habits change as well. We tend to crave stews, soups, root vegetables, and more carbohydrates — or anything warm. Gone are the cold crisp salads from summer. Our big eating holidays are during the fall and winter when people tend to eat more and exercise less. The result is usually a few added pounds if you are not mindful of your eating.

Some people suffer from Seasonal Affective Disorder, which affects people when it gets colder outside and the days are shorter with less daylight. Some of us want to spend more time in bed because the brain does not register that is time to get up when it is still dark outside. Symptoms of SAD are significant distress, depression, moodiness, and loss of energy. One way to treat SAD is with light therapy.

What all this means, is we are wired to slow down, sleep a bit more, and enjoy our family and friends. Don’t worry if you miss one workout during the week to sleep in — you really do need that extra sleep this time of year.

Catherine Benton is a nutritionist and life coach who lives in San Francisco. She is the co-founder and co-owner of Personalized Nutrition Solutions. Email: [email protected]

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