Stay Well, Stay Sharp with Vitamin D

beach chairs and umbrella on the beachDuring the summer you probably forget all about the colds, sore throats, and viruses that strike you and your family every winter.

Why do people get sick more in the winter? It used to be thought it was from getting cold, lack of fresh air, or from being in closed buildings.

Many experts now believe people get sick in the winter from having low levels of vitamin D.  That makes sense since most of the US population is lacking in this essential nutrient.

Vitamin D — What’s It Good For?

Vitamin D is technically not a vitamin, it’s a pre-hormone that’s created when your skin is exposed to sunlight.

It’s the only nutrient that’s created from sunlight. I love that we can create nutrients from the sun — just like plants!

Vitamin D is close to being nature’s cure-all. It’s a fantastic immune system booster.

It’s been found to be protective against cancer, diabetes, heart disease, high blood pressure, high cholesterol, and osteoporosis. 

Studies have shown it can lift your mood, banish depression, improve memory, and increase problem-solving ability. Inadequate levels may contribute to the depression many people feel in the winter.

Over 2,000 genes have vitamin D receptors. Lack of vitamin D can lead to cancer because without it, cells don’t get the message to stop reproducing.

Here’s a chart that compares the healthy benefits of adequate vitamin D levels versus the health risk of low levels.

vitamin d health chart

3 Reasons Why You’re Probably Deficient

It’s estimated that 80-90% of adults in North America have inadequate levels of vitamin D.

Getting 20 minutes of sun exposure on large surface areas of your body, such as arms or legs, twice a week is said to do the trick. But this must be without sunscreen, in the right latitude, and at the right time of year.

Here are some things that can interfere with vitamin D formation.


Even if you are outside a lot when the sun is shining, wearing sunscreen prevents vitamin D formation.

I live in southern Arizona where the sun almost always shines and I spend time outside every day. However, since I wear sunscreen I found that I was still vitamin D deficient! I now take a vitamin D supplement every day and wear sunscreen some of the time.


Draw a line across the US from Los Angeles to Atlanta. If you live north of this line, the sun’s rays are too weak to trigger vitamin D production except during the summer.

Time for some fun science! Here’s a way to tell if the sun’s rays are strong enough. Go outside, stand in the sun, and look at your shadow.

The more direct the sun’s rays are, the shorter your shadow will be.

shadow lengths

A good rule of thumb is that if your shadow is your height or longer, the sun’s rays strike at too great an angle to promote vitamin D formation.

Skin Color

Our different skin tones evolved depending on how much sunshine our ancestors were exposed to.

Light-skinned people from very northern areas evolved to utilize sunshine more efficiently. If you have dark skin, you need even more sun exposure to get adequate exposure levels, up to one hour a day.

Alternative Sources 

Some foods, like milk, are fortified with vitamin D, but it’s the D2 form not D3. D2 isn’t very well utilized, so don’t count on fortified food sources to meet your requirements.

The D3 version is found in fatty fish, but you’d have to eat 5 sardines a day to get enough.

Below is an excellent discussion about vitamin D between Diane Sawyer and Dr. Mehmet Oz of The Dr. Oz Show.

Diane had her vitamin D levels tested and was surprised to find that she is one of the 100,000,000 Americans who are deficient.

Diane takes one for the team and downs a spoonful of cod liver oil, an old-fashioned vitamin D source. She clearly finds it disgusting, but like a good journalist takes it in stride while she finishes the interview.

Cod liver oil may have been all our grandmothers had to offer, but now there are more advanced and pleasant ways to supplement.   

The Next Step — Know Your Levels, Then Supplement

Vitamin D deficiency symptoms — muscle pain, weak bones, low energy, lowered immunity, depression, mood swings, and sleep problems — can be mistaken for many other health problems.

The only way to know for sure if you need vitamin D is to have a blood test to check your 25-hydroxy level. You can see your doctor to order the test but you don’t have to.

You can also purchase a vitamin D test online through True Health Labs. I think this is one of the greatest concepts ever!

True Health Labs lets you arrange to have this (and many other tests) done at a local lab without your doctor’s involvement. Medical tests done this way often save up to 80% of what you’d pay if you went through your doctor.

This is a fantastic way to save money if you aren’t covered by insurance or haven’t met your deductible. Many people prefer doing this to have more control over their health or retain their privacy.

Truth Health Labs provided this chart, so you know what your results should look like.

vitamin d test results

Now is the time to start paying attention to your vitamin D levels to keep your immune system strong enough to fight off any sicknesses this winter.

It is also one of the smartest things you can do to keep your brain in top working order to avoid feeling blue, lethargic, or depressed during the winter months.

Want to boost your memory, focus, clarity and mood? Find help in the Be Brain Fit Store.

If you want your brain to be healthy and sharp, learn how to treat it right.


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