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Could Vitamin D Keep You Healthy This Winter?

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Despite increasing scientific scrutiny of the benefits of vitamin D, there is still mystery and confusion about this essential nutrient. Part of the complexity is due to the fact that vitamin D is not simply a nutrient. It functions as a hormone and affects virtually every cell in the body.

Because the skin manufactures vitamin D only after exposure to sunlight, circulating levels often drop during winter months. That's why grandmothers used to dose their families with cod liver oil rich in vitamin D as a winter tonic.

Science is still trying to figure out whether the grandmothers were right. As so often happens, the studies are inconclusive. Some controlled studies show that children given vitamin D supplements have fewer colds and other respiratory infections (Pediatrics, Sept. 2012). A recent study of adults examined whether 1000 IU daily of vitamin D prevented upper respiratory tract infections better than placebo and found it did not (Clinical Infectious Diseases, Nov. 15, 2013). Severe illness was less common among those taking vitamin D but overall there was no protection against colds and flu-like illnesses.

People who have higher levels of vitamin D circulating in their bloodstreams are less likely to experience other sorts of infections, however. One recent study found that overweight individuals undergoing gastric bypass surgery were three times more likely to suffer an infection following the surgery if their levels of vitamin D (25-hydroxyvitamin D) were below 30 ng/ml (JAMA Surgery, online Nov. 27, 2013). This is a significant concern, because obese people are much more likely to have low circulating levels of the vitamin (Journal of Epidemiology and Community Health, online, Nov. 6, 2013).

An epidemiological study found that Americans with 25-hydroxyvitamin D blood levels below 30 ng/ml had a 56 percent greater likelihood of coming down with pneumonia (PLoS One, Nov. 15, 2013). Low levels of this vitamin have also been linked to inflammation (including arthritis), cardiovascular disease, high cholesterol, diabetes, weight gain, infections, multiple sclerosis, depression or anxiety, cognitive decline and poor physical functioning (The Lancet Diabetes & Endocrinology, online Dec. 6, 2013).

In addition, adequate levels of vitamin D are associated with a reduced risk of falls and broken bones and with better hand and leg strength (Journal of the American Geriatric Society, Nov., 2013).

We have more details on the health benefits of vitamin D in our Guide to Vitamin D Deficiency. In it, we describe how to interpret tests of 25-hydroxyvitamin D as well as how to increase blood levels with supplements. 

We will have to wait for better studies to determine the best regimen for supplementing vitamin D for prevention of cognitive decline as well as heart disease. In the meantime, though, it makes sense to prevent winter deficiency of this critical vitamin. When we spoke recently with Dr. David Perlmutter, he pointed out that there is no one "best" dose for vitamin D; the amount needed to achieve a healthy blood level is highly individual. But since it is possible to test for vitamin D in the blood, the supplement can be tailored for the patient.

 

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Oh, now I get it! My mother used to give us cod liver oil when I was young. I still remember the taste. It is true that we were the healthiest kids and got fewer colds and only occasional 'grip', but it left me with a dislike for fish all my life.

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My husband use to get multiple flus, cold or other respiratory illnesses every winter. One year he started taking Vitamin D (1000 IU) and that winter he didn't get sick once. We both now take Vitamin D and we both get sick a lot less and recover much faster when we do. I have recommended this to others who have told me that they've had the same results after taking Vitamin D.

I haven't had any respiratory or throat infections since I've been taking Vitamin D-3 supplements, and getting some sun on my skin in the summer. And my asthma is much better, too. No colds, flu, pneumonia or anything else. I'll continue to take my Vitamin D-3, because I do believe that it is very helpful, for many reasons. There are no side effects and adverse reactions, like there is with drugs, either. That is a major plus.

My mom did NOT give us cod liver oil and we caught every flu bug, strep throat and cold going around. I have NOT had a cold or flu since March of 1985 and my son didn't have a cold or flu until he was about 13.

What made the difference? I got tested for allergies in '85 and learned about vitamin C. My son started out at 6 mo. old with supplemental vitamin C. He decided he was old enough to make his own decisions about vitamins as a teenager and chose not to take them. I stood down and waited. In less than three weeks he got his first cold. Not even a bad one, but he thought he was going to die! At age 35 he still takes his vitamins.

The test mentioned above that showed no results with 1000 mg was designed to fail. Every adult needs at least 5,000 iu of vitamin D-especially in the winter months. Many of us need several times that to get our levels up. It took many years to get my level up. My Dr. had me do sunlight firstly and it made NO difference. Then we started with the D supplement. My Dr. upped the dose every time I got tested and finally threw up his hands and said "double it!" No, that wasn't enough to get my level up either. Every body is different and you mus check your own levels.

One simply does NOT know what their level is without testing. If my level had been up I probably wouldn't have had a problem with cervical cancer. Vitamin C kept me from the usual problems of colds and flu but I needed the vitamin D to protect me from the real baddy.

When I take Vitamin D3, I get terrible headaches. I wish I could purchase Vitamin D2 over the counter. I can only get D2 with a prescription, but that requires yet another visit to the doctor.

Everyone should by now have noticed that whenever there is a "scientific" study to evaluate the efficacy of a supplement or vitamin, the dosages used in the study are so low as to be ridiculous. 400IU of vitamin E, 1,000 or even 400IU of vitamin D. Was D2 or D3 used?. Probably D2 which is not very effective in my opinion. Whenever you just "know" that your study is going to fail, the outcome is predetermined. I am 85, my wife is 88. We both take 5000IU of D3 daily. Neither of us have had a cold or any other respiratory ailment for over ten years.

The way I understand it, it's not so much how much Vit D one takes, but how much one needs to take to keep blood levels in the optimum range. From what is generally said, this is usually 5000iu D3. Without measuring blood levels in these studies, there is no way of knowing if the subjects have proper blood levels. At 1000 iu, however, one can almost rest assured that most do not. Also, Vit D apparently works in conjunction with K2 and Vit A.

It seems the reason many of these so called "trials" come up with disappointing results (disappointing to all except the drug companies) is because the supplements are looked at alone, instead of in conjunction with others needed for them to be effective as well as the amounts being way to small. Let's have a study giving folks with genetic high cholesterol given 2 mg of a statin and see what effect it has. I'll bet it won't work!

Or how about giving someone with pneumonia 10% of the effective antibiotic dose. I guess that would prove antibiotics don't work.

I do better when I take 5000 units of D-3, and double it in winter. I also take Vitamin K2 and magnesium for the sake of my bones. If I get lazy and don't take my supplements I seem to catch whatever germ my grandchildren bring home from day care.

Just read the article on Vitamin D2 on 2/21/14 which confused me.
Checking back here for a possible answer about D2 and D3, I am still confused.
This article states 25-hydroxyvitamin D. Which D is that? My bottle of D3 only says D3.
I guess I am dense and need some clarification please.
Thank you!

@mary;Simply. D3 is the D vitamin which is manufactured in the human skin by the action of the sun. D3 is Cholicalciferol and is 30-40% more bioavailable than D2. D2 is not found in free form in humans, D3 is. The reason that D2 is more commonly found and is generally used in supplements is because it is easier to synthesize and less expensive. It is found in plants and animal (and human) tissue. You can get more detailed info in your browser. Just type. "What is the difference between D2 and D3". Your bottle might say (as Cholicalciferol)

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