Wicked Winter Health Myths

winter mythsWe’ve heard them all – those silly theories about how winter affects our health: You’ll catch a cold if you go outside with wet hair!  Turkey will make you sleepy. Are these wicked winter health myths true? Let’s debunk some health myths we’ve all wondered about.

Being Cold will Give You A Cold

Folklore says getting chilled, such as going outside with wet hair or getting your feet wet in the winter, will cause you to catch a cold. Researchers have published theories that both substantiate and disprove this folklore. For example, some studies have proposed that crowding of people in warm indoor places is what facilitates more rapid and frequent transfer of cold viruses in winter months. Other studies argue changes in the nasal passage when the body is cold allow the cold virus to invade and multiply causing illness. But, a research team at Yale reported what may be the most interesting theory. They reported that warm cells infected with the common cold virus were more likely to successfully undergo cell suicide, thus stopping the virus from replicating, while cells in colder temperatures were not as likely to self-destruct. In other words, being cold may lower your body’s ability to fight off a cold. Perhaps this old folklore has some truth behind it.

We All Put On Winter Weight

We would all love to blame our desire to fatten-up in the winter on an evolutionary drive to survive the cold, but that is likely not to be true. Fact: Cold weather actually stimulates higher caloric burning by your body. A 2013 study in the Journal of Clinical Investigation announced that frequent cold exposure increases energy expenditure and may counteract obesity. Sounds like we could all be thinner by taking a walk outside in the winter during our mid-day breaks. What’s causing the weight gain? It’s more likely the comfort foods, dreary days that make you feel anchored to the couch, and holiday stress that causes us to put on weight in the winter. According to a study published in Nutrition Review, holiday weight gain (the 6 weeks between American Thanksgiving and Christmas) accounted for half of our annual weight gain.

Turkey Makes You Sleepy

That post-festive feast coma is usually blamed on the turkey, as it is a good source of tryptophan. Tryptophan is an amino acid – the building blocks of proteins. The body uses tryptophan to make serotonin and melatonin. Serotonin is a neurotransmitter, which according to scientists, has some effects on sleep. However, the tryptophan in turkey is not enough to induce drowsiness. In fact, chicken contains comparable amounts of tryptophan as turkey, suggesting that if it’s tryptophan making us feel sluggish after our holiday feast, than we should also feel sluggish after eating chicken at a summer barbeque. The tryptophan in turkey is also a precursor to melatonin, a sleep-associated hormone. Melatonin helps people fall asleep and maintains the body’s internal clock. Truthfully, our drowsiness after a big feast is probably not caused by tryptophan at all. Our drowsiness after a holiday feast is likely caused by a combination of things: over stuffing ourselves with high fat and protein foods causing our body to divert resources to digestion; the sugar spike from dessert; topped-up with the drowsy sensation alcoholic drinks cause.

References:

Roberts SB and J Mayer. Holiday Weight Gain: Fact or Fiction? Nutr Rev 2000 Dec;58(12):378-9. http://www.ncbi.nlm.nih.gov/pubmed/11206847

Anouk J, et al. Cold acclimation recruits human brown fat and increases nonshivering thermogenesis. J Clin Invest. 2013;123(8):3395–3403 http://www.jci.org/articles/view/68993

Cold Viruses Thrive in Frosty Conditions. Nature May 20, 2013. http://www.nature.com/news/cold-viruses-thrive-in-frosty-conditions-1.13025

(Note: Research study not yet published in clinical journal, only reported in conference).

Johnson C, Eccles R. (2005) Acute cooling of the feet and the onset of common cold symptoms. Family Practice 22: 608-613. http://fampra.oxfordjournals.org/content/22/6/608

Eccles R. An explanation for the seasonality of acute upper respiratory tract viral infections. Acta Otolaryngologica (Stockholm) 2002; 122:183-191.http://www.ncbi.nlm.nih.gov/pubmed/11936911