How to Avoid Getting the Flu and Colds During Winter

Most people understand that, as winter approaches, so does the chance of catching the flu or a cold.  As a result, they stock up on over-the-counter medications like NyQuil, Ibuprofen, Sudafed, Mucinex, and generic cold medicine.  However, they fail to question why colds and flu are more common in the winter months; they just accept it.  Are you one of them?

I’d like for you to contemplate exactly why more people get sick during the winter months.  Does cold weather somehow cause bacteria to divide faster and viruses to replicate at a higher rate, making them more abundant in our surroundings?  No, it does not.

Does cold weather somehow weaken your body, making it more susceptible to microbial invasion?  No, not cold in itself.  Your body maintains its temperature around 98.6 degrees Fahrenheit whether you feel cold or hot.

Having ruled out these false beliefs, the next step is to think about what changes occur in our environment and/or habits as winter approaches, that may open us up to infection.

Here is a list of pertinent factors, off the top of my head:


  1. Temperatures drop
  2. People spend more time indoors
  3. People wear more layers of clothing, covering more of their body
  4. Days are shorter
  5. The sun’s rays are less direct as they reach Earth’s surface
  6. More cloud cover
  7. More rain & snow
  8. Less availability of seasonal fruits & vegetables
  9. Holiday celebrations – eating high calorie foods
  10. For some, holiday stress, depression

So, which ones do you think are responsible for the increase in colds and flu during the winter?

To me, numbers 3-6 are the main culprit.  These factors, altogether, result in less sun UV ray exposure to the skin.  The sun’s UV rays are needed in order for your skin to synthesize vitamin D.  Without adequate vitamin D levels, the body is more prone to disease.

Vitamin D’s main function is to enable calcium absorption in the gut to maintain balanced serum calcium and phosphate levels to ensure proper mineralization of bone, and provide calcium ions for proper neuromuscular function.

Other critical roles of vitamin D include modulation of cell growth, immune function, and reduction of inflammation.

Note:  Vitamin D itself is biologically inactive and must undergo conversion into 25(OH)D in the liver and then into the active form 1, 25 (OH2)D in the kidneys.  Serum 25(OH)D is the best indicator of your vitamin D levels and is what is measured in blood tests.

Could it be that the drop in vitamin D levels from decreased exposure to sunlight during the winter months somehow creates conditions in the body where bacteria and viruses can thrive, explaining why more people get sick in the winter?

It makes logical sense.

According to the National Institute of Health, season, time of day, length of day, cloud cover, smog, skin melanin content, and sunscreen are among the factors that affect UV radiation exposure and vitamin D synthesis.

Laboratory and animal evidence as well as epidemiologic data suggest that vitamin D status could affect cancer risk. Strong biological and mechanistic bases indicate that vitamin D plays a role in the prevention of colon, prostate, and breast cancers.  How it does this is uncertain.  If vitamin D affords these powerful protective health benefits, it is plausible that it can do the same for the colds and flu.  In fact, a study done in Japan showed that schoolchildren taking 1,200 units of vitamin D per day during the winter time reduced their risk of getting influenza A infection by about 40 percent.

The factors that affect UV radiation exposure and research to date on the amount of sun exposure needed to maintain adequate vitamin D levels make it difficult to provide general guidelines; however, the conventional belief is that approximately 5–30 minutes of sun exposure between 10 AM and 3 PM (when the sun’s rays are strongest) at least twice a week to the arms, legs, or back without sunscreen usually lead to sufficient vitamin D synthesis.

Optimal levels of serum 25(OH)D are between 50-70 ng/ml; anything below 50 is considered deficient.

So, what can you do to avoid experiencing a drop in vitamin D during Winter? (and reduce your chances of getting a cold or the flu)

Here are my suggestions:

1.  Increase your intake of Vitamin-D containing foods.  There are not many foods that contain Vitamin D, but they include sardines, mackerel, salmon, mushrooms, and cod liver oil (my favorite).

2.  Supplement with Vitamin D.  The Institute of Medicine recommends

  • 600 IU of vitamin D a day for everyone ages 1 to 70
  • 800 IU of vitamin D a day for those 71 and older

However, some people, especially natural healthcare advocates believe that these numbers are inadequate.  They believe that 3,000 IU of vitamin D per day is a better recommendation (for those with low Vitamin D levels – less than 20 ng/ml) in order to achieve appreciable therapeutic effect; the main reason being that much of oral Vitamin D does not make it into your cells; perhaps as much as 75%.  Since vitamin D is fat soluble, it helps to take your vitamin D after a meal rich in saturated fats, or better yet with fish oil.

3.  Deliberately expose large areas of your skin to the sun during the winter months (not your face, though because it gets enough exposure and is more susceptible to wrinkling from UVA rays).  Expose your trunk (back and front) and legs, primarily.  Remember, the sun’s rays are weaker during winter so 20-25 minutes at least 2x/ week is a good rule of thumb; being careful not to get sun burned.

If it is too cold outside, find an area in your home where the sun shines through a window onto your floor.  Open the window (most windows are UV tinted to block out UV rays, which you don’t want), place a mat on the floor where the sunlight lands and sun bathe on it.  Again, make sure to cover your face.

Another option, especially if you are in area that gets long bouts of rain, snow or overcast skies is to use an Indoor UVB Lamp.  This can be enough to encourage vitamin D synthesis when ambient light is low.

Other steps to take to avoid getting the flu during the winter:

Being aware of what’s around you and being conscious of what you are doing; i.e., being vigilant, can go a long way towards avoiding contracting a cold or the flu.

Here are my recommendations:

1.  Wash your hands frequently throughout the day.  Use warm running water, soap, and rub your hands vigorously under the running water, paying close attention to the fingertips and between the fingers.  Do for at least 1 minute.

2.  Avoid directly touching frequently handled items in public:  all doorknobs, levers and handles (especially bathroom door knobs), toilet flush handles, telephone handsets, chair backs, elevator buttons — anything in public that is meant to be touched or grabbed.  The same goes for currency — coins, bills.  These items have high concentration of germs.  Use a glove or napkin when handling them.

3.  Watch out for glasses and silverware in restaurants.  Potentially sick waiters/ waitresses handle them.  It annoys me when I see a waiter pick up a bunch of drinking glasses by sticking his/her fingers inside and pinching them together; or grabbing spoons and forks on their “business” end when setting a table.  Where were those fingers just a few minutes ago?, I wonder.  Also, I have seen on many occasions waiters delivering bowls of soup to a table where the soup touches their thumb as they  grasp the soup bowl.  This is a good way to get food-borne illness.

4.  Avoid touching your eyes and mucous membranes.  These areas are highly vascularized and don’t have the protection of a skin layer, making them ideal entry points for pathogens.

5.  Be especially vigilant whenever you are in the vicinity of large groups of people— busy stores, classes, lectures, restaurants, sidewalks.  If there is a lot of coughing and sneezing going on, consider breathing through a thin scarf.  Whenever someone sneezes, an invisible mist hangs in the air for several seconds; the fine droplets of lung fluid may contain transmittable viruses and/or bacteria and you can walk right into it without even knowing it.

6.  Use a humidifier at night and pour some eucalyptus oil into it.  Also, get a handkerchief and sprinkle a few drops of eucalyptus oil on it, keep it in your pocket and breathe the fumes periodically.  Eucalyptus has antibacterial properties, and it wouldn’t hurt to make it difficult for pathogens to settle in your body.

7.  Take anti-viral foods and immune-strengthening supplements.  My recommendations are high dose Vitamin C, garlic, onions, mushroom extract, elderberry extract (Sambucol) and zinc.

Now, isn’t it worthwhile to practice these behaviors and make it through the winter months without a day looking like this poor guy?sick

In summary, there are simple yet powerful and effective strategies you can implement that can guard you against the flu and colds during the winter.  The old adage “An ounce of prevention is worth a pound of cure” says it all.

Posted in Nutrition.